151 results on '"K. Linden"'
Search Results
2. An actinometric method to characterize performance of reflecting UVC reactors used for water treatment
- Author
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P. Sperle, A. Mirlach, K. Linden, U. Hübner, and J.E. Drewes
- Subjects
Environmental Engineering ,Ecological Modeling ,Pollution ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering - Published
- 2023
3. Intraventricular Flow Dynamics in Single Right Ventricle Patients with Real-Time Echocardiography and Computational Modeling Provide Additional Insight into Cardiac Function
- Author
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M. Neidlin, A. Grünwald, J. Korte, N. Wilmanns, C. Winkler, S. Gross-Hardt, U. Steinseifer, K. Linden, and U. Herberg
- Published
- 2022
4. Attitudes of German GP trainees regarding add-on training programs differ if in office or hospital training phase
- Author
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Dmg, Wild, K, Linden, T, Welchowski, D, Dehnen, and B, Weltermann
- Subjects
Adult ,Attitude ,Humans ,Internship and Residency ,Female ,Curriculum ,Hospitals - Abstract
Many residents are exposed to negative attitudes towards primary care during hospital training. Attractive add-on training programs exist, but it is unclear whether these need to be tailored to the location of training (hospital vs. office). We report differences in learner attitudes from a large German add-on training program.Between 2017 and 2020, a regional network offered 31 quarterly seminars to primary care residents. The seminars addressed medical content, practice management and mentoring. We elicited participants' satisfaction, perceived topic relevance, preferences for future seminars, work situation and employer support for participation. A proportionate odds model was used to assess predictors of ratings; results were stratified by training location (hospital vs. office).Most respondents were female (380/575 = 70.0%), aged between 26 and 40 (80.8%), and had on average 3.54 ± 1.64 years of residency training. The majority (83.8%) was working in an office and full-time (63.0%). Overall evaluations were positive (very satisfactory 72.1%). Comparing residents in the hospital phase vs. the office phase, overall seminar ratings of the perceived impact on the motivation for primary care did not differ (p = 0.73 vs. 0.18, respectively). Hospital-based residents were less likely to rate the topics as relevant (39.4% vs. 55.7%, p = 0.02) and had different preferences for future seminar topics (top 3: palliative care, emergencies and chronic care vs. billing, disease management and practice finances for hospital and office phase, respectively).Keeping primary care residents motivated may require education tailored to training location. Our findings may be of interest to teachers, administrators and policymakers.
- Published
- 2021
5. Formyl peptide receptor 2 orchestrates mucosal protection against Citrobacter rodentium infection
- Author
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S. Sharba, V. Venkatakrishnan, M. Padra, M. Winther, M. Gabl, M. Sundqvist, J. Wang, H. Forsman, and S. K. Linden
- Subjects
fpr2 ,mucin ,mucus ,colitis ,enteropathogenic escherichia coli ,lcsh:RC109-216 ,digestive system ,citrobacter rodentium ,lcsh:Infectious and parasitic diseases - Abstract
Citrobacter rodentium is an attaching and effacing intestinal murine pathogen which shares similar virulence strategies with the human pathogens enteropathogenic- and enterohemorrhagic Escherichia coli to infect their host. C. rodentium is spontaneously cleared by healthy wild-type (WT) mice whereas mice lacking Muc2 or specific immune regulatory genes demonstrate an impaired ability to combat the pathogen. Here we demonstrate that apical formyl peptide receptor 2 (Fpr2) expression increases in colonic epithelial cells during C. rodentium infection. Using a conventional inoculum dose of C. rodentium, both WT and Fpr2−/− mice were infected and displayed similar signs of disease, although Fpr2−/− mice recovered more slowly than WT mice. However, Fpr2−/− mice exhibited increased susceptibility to C. rodentium colonization in response to low dose infection: 100% of the Fpr2−/− and 30% of the WT mice became colonized and Fpr2−/− mice developed more severe colitis and more C. rodentium were in contact with the colonic epithelial cells. In line with the larger amount of C. rodentium detected in the spleen in Fpr2−/− mice, more C. rodentium and enteropathogenic Escherichia coli translocated across an in vitro mucosal surface to the basolateral compartment following FPR2 inhibitor treatment. Fpr2−/− mice also lacked the striated inner mucus layer that was present in WT mice. Fpr2−/− mice had decreased mucus production and different mucin O-glycosylation in the colon compared to WT mice, which may contribute to their defect inner mucus layer. Thus, Fpr2 contributes to protection against infection and influence mucus production, secretion and organization.
- Published
- 2019
6. Concurrent heavy use of general and oral health services among Finnish adults
- Author
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H, Salusjärvi-Juopperi, M, Tolvanen, J K, Linden, A, Nihtilä, and S, Lahti
- Subjects
Adult ,Male ,Adolescent ,Humans ,Female ,Oral Health ,Public Health ,Dental Health Services ,Finland - Abstract
The aim was to identify heavy users of public health (PHS) and public oral health (POHS) services and combined and concurrent users of these services.Numbers of 18+ year-old patients and their visits to POHS (12,124 patients) and PHS (28,479 patients) were collected from two patient registers in a Finnish town in 2013. The combined dataset consists of 32,481 patients. Using a highest decile criterion for both for POHS and PHS, those patients who had made 8 or more visits were categorised as heavy users. Patients who had made total of 10 or more visits to the POHS and/or PHS were categorised as combined heavy users. Patients who had made 8 or more visits to both the POHS and PHS were categorised as concurrent heavy users (195 patients).Heavy users of POHS were more often men and those of PHS more often women. Combined heavy users were likely to be women and to be older. The combined heavy users accounted for 40% of all visits of POHS and/or PHS. Among them 30% did not have any POHS visits and 4% did not have any PHS visits. Concurrent heavy use was rare, involving 0.06% of all patients, but made 3.4% of all visits.Of the patients making 10 or more POHS and/or PHS visits, only five percent were concurrent heavy users of both services. As many non-communicable diseases share common risk factors the combined heavy users of PHS should be directed to use POHS and vice versa.
- Published
- 2020
7. Src family kinase inhibitors blunt PACAP-induced PAC1 receptor endocytosis, phosphorylation of ERK, and the increase in cardiac neuron excitability
- Author
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Jean C. Hardwick, Anne K. Linden, Laura A. Merriam, Thomas R. Buttolph, Victor May, Rodney L. Parsons, John D. Tompkins, Todd A. Clason, and Beatrice M. Girard
- Subjects
Male ,0301 basic medicine ,MAPK/ERK pathway ,medicine.medical_specialty ,Physiology ,Guinea Pigs ,Adenylate kinase ,In Vitro Techniques ,Mitogen-activated protein kinase kinase ,Biology ,Cell Line ,Membrane Potentials ,03 medical and health sciences ,Internal medicine ,medicine ,Animals ,Humans ,Calcium Signaling ,Src family kinase ,Phosphorylation ,Extracellular Signal-Regulated MAP Kinases ,Receptor ,Protein Kinase Inhibitors ,ADCYAP1R1 ,Mitogen-Activated Protein Kinase Kinases ,Neurons ,Heart ,Cell Biology ,Endocytosis ,Cell biology ,Enzyme Activation ,Pyrimidines ,src-Family Kinases ,030104 developmental biology ,Endocrinology ,medicine.anatomical_structure ,Pituitary Adenylate Cyclase-Activating Polypeptide ,Female ,Neuron ,hormones, hormone substitutes, and hormone antagonists ,Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I ,Research Article - Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP, Adcyap1) activation of PAC1 receptors ( Adcyap1r1) significantly increases excitability of guinea pig cardiac neurons. This modulation of excitability is mediated in part by plasma membrane G protein-dependent activation of adenylyl cyclase and downstream signaling cascades. However, additional mechanisms responsible for the enhanced excitability are activated following internalization of the PAC1 receptor and endosomal signaling. Src family kinases play critical roles mediating endocytosis of many trophic factor and G protein-coupled receptors. The present study investigated whether Src family kinases also support the PACAP-induced PAC1 receptor internalization, phosphorylation of ERK, and enhanced neuronal excitability. Using human embryonic kidney cells stably expressing a green fluorescent protein-tagged PAC1 receptor, treatment with the Src family kinase inhibitor PP2 (10 µM) markedly reduced the PACAP-induced PAC1 receptor internalization, and in parallel, both PP2 and Src inhibitor 1 (Src-1, 2 µM) reduced ERK activation determined by Western blot analysis. In contrast, Src family kinase inhibitors did not eliminate a PACAP-induced rise in global calcium generated by inositol (1,4,5)-trisphosphate-induced release of calcium from endoplasmic reticulum stores. From confocal analysis of phosphorylated ERK immunostaining, PP2 treatment significantly attenuated PACAP activation of ERK in neurons within cardiac ganglia whole mount preparations. Intracellular recordings demonstrated that PP2 also significantly blunted a PACAP-induced increase in cardiac neuron excitability. These studies demonstrate Src-related kinase activity in PAC1 receptor internalization, activation of MEK/ERK signaling, and regulation of neuronal excitability. The present results provide further support for the importance of PAC1 receptor endosomal signaling as a key mechanism regulating cellular function.
- Published
- 2018
8. Pituitary Adenylate Cyclase-Activating Peptide in the Bed Nucleus of the Stria Terminalis Mediates Stress-Induced Reinstatement of Cocaine Seeking in Rats
- Author
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Olivia W Miles, Sayamwong E. Hammack, Victor May, Mark E. Bouton, Anne K. Linden, and Eric A. Thrailkill
- Subjects
Male ,0301 basic medicine ,Agonist ,endocrine system ,medicine.medical_specialty ,Microinjections ,medicine.drug_class ,Drug-Seeking Behavior ,Self Administration ,Extinction, Psychological ,03 medical and health sciences ,0302 clinical medicine ,Cocaine ,Recurrence ,Internal medicine ,medicine ,Animals ,Chronic stress ,Receptor ,Pharmacology ,Antagonist ,Extinction (psychology) ,Electric Stimulation ,Peptide Fragments ,Rats ,Behavior, Addictive ,Psychiatry and Mental health ,Stria terminalis ,Pituitary adenylate cyclase-activating peptide ,030104 developmental biology ,Endocrinology ,Pituitary Adenylate Cyclase-Activating Polypeptide ,Original Article ,Septal Nuclei ,Self-administration ,Psychology ,Stress, Psychological ,hormones, hormone substitutes, and hormone antagonists ,030217 neurology & neurosurgery - Abstract
Stressors often contribute to difficulties in maintaining behavior change following a period of abstinence, and may play a significant role in drug relapse. The activation of pituitary adenylate cyclase-activating peptide (PACAP) systems in the bed nucleus of the stria terminalis (BNST) mediates many consequences of chronic stressor exposure. Here we ask whether PACAP is also involved in producing reinstatement in a model of stress-induced relapse to drug taking. Rats self-administered cocaine for 1 h daily over 10 days that was followed by 20 days of extinction training in which lever pressing no longer produced cocaine. In experiment 1, quantitative PCR (qPCR) was performed at several stages to determine transcript levels of PACAP and corresponding receptors. Reinstatement of cocaine seeking was then tested after footshock exposure in different groups of rats that were pretreated with vehicle solution, a PAC1 receptor antagonist (experiment 2), or a PACAP agonist (experiment 3) without footshock. In experiment 1, cocaine self-administration increased BNST PACAP transcript levels similar to what we have previously reported with chronic stress. In experiment 2, intra-BNST infusions of the PAC1/VPAC2 antagonist, PACAP 6-38, prevented footshock-induced reinstatement of extinguished cocaine seeking. In experiment 3, intra-BNST PACAP infusion reinstated previously extinguished cocaine-seeking behavior in the absence of footshock. Cocaine self-administration elevated BNST PACAP, and BNST PACAP receptor activation was necessary and sufficient for stress-induced reinstatement of cocaine seeking. These data suggest that BNST PACAP systems may be viable targets for relapse prevention.
- Published
- 2017
9. Left Atrial Pediatric Reference Volumes Using Real-Time 3D-Echocardiography
- Author
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C. Winkler, F. Goldschmidt, Kai Thorsten Laser, Robert Dalla-Pozza, Ulrike Herberg, and K. Linden
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,business.industry ,Left atrial ,Internal medicine ,Cardiology ,Medicine ,Surgery ,Cardiology and Cardiovascular Medicine ,business ,Real time 3d echocardiography - Published
- 2017
10. Data-Driven Decision Support for the Diagnosis and Prognosis of Critical Heart Failures Based on 3D Echocardiography Data
- Author
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C. Winkler, Thomas Schultz, Johannes Breuer, Ulrike Herberg, and K. Linden
- Subjects
Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Decision support system ,business.industry ,medicine ,Surgery ,Cardiology and Cardiovascular Medicine ,Intensive care medicine ,business ,3d echocardiography ,Data-driven - Published
- 2017
11. Formyl peptide receptor 2 orchestrates mucosal protection against
- Author
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S, Sharba, V, Venkatakrishnan, M, Padra, M, Winther, M, Gabl, M, Sundqvist, J, Wang, H, Forsman, and S K, Linden
- Subjects
Male ,Mice, Knockout ,Fpr2 ,colitis ,Enterobacteriaceae Infections ,Mucins ,Epithelial Cells ,enteropathogenic Escherichia coli ,digestive system ,Receptors, Formyl Peptide ,Mice, Inbred C57BL ,Mice ,mucus ,Mucin ,Animals ,Citrobacter rodentium ,Intestinal Mucosa ,Research Paper - Abstract
Citrobacter rodentium is an attaching and effacing intestinal murine pathogen which shares similar virulence strategies with the human pathogens enteropathogenic- and enterohemorrhagic Escherichia coli to infect their host. C. rodentium is spontaneously cleared by healthy wild-type (WT) mice whereas mice lacking Muc2 or specific immune regulatory genes demonstrate an impaired ability to combat the pathogen. Here we demonstrate that apical formyl peptide receptor 2 (Fpr2) expression increases in colonic epithelial cells during C. rodentium infection. Using a conventional inoculum dose of C. rodentium, both WT and Fpr2−/− mice were infected and displayed similar signs of disease, although Fpr2−/− mice recovered more slowly than WT mice. However, Fpr2−/− mice exhibited increased susceptibility to C. rodentium colonization in response to low dose infection: 100% of the Fpr2−/− and 30% of the WT mice became colonized and Fpr2−/− mice developed more severe colitis and more C. rodentium were in contact with the colonic epithelial cells. In line with the larger amount of C. rodentium detected in the spleen in Fpr2−/− mice, more C. rodentium and enteropathogenic Escherichia coli translocated across an in vitro mucosal surface to the basolateral compartment following FPR2 inhibitor treatment. Fpr2−/− mice also lacked the striated inner mucus layer that was present in WT mice. Fpr2−/− mice had decreased mucus production and different mucin O-glycosylation in the colon compared to WT mice, which may contribute to their defect inner mucus layer. Thus, Fpr2 contributes to protection against infection and influence mucus production, secretion and organization.
- Published
- 2019
12. Disparities in Treatment for Gallbladder Carcinoma: Does Treatment Site Matter?
- Author
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A, Melillo, K, Linden, F, Spitz, U, Atabek, J, Gaughan, and Young K, Hong
- Subjects
Treatment Outcome ,Chemotherapy, Adjuvant ,Humans ,Cholecystectomy ,Gallbladder Neoplasms ,Propensity Score ,Neoplasm Staging - Abstract
Current treatment guidelines for gallbladder cancer range from simple cholecystectomy to regional hepatic resection. Treatment patterns for radical resection and adjuvant chemotherapy vary. We aim to determine if there is any disparity in treatment or difference in survival between academic versus community treatment centers.The National Cancer Database (NCDB) was queried from 2004 to 2014 for gallbladder carcinoma. Cases were stratified into treatment sites as "Community Cancer Center" (CCC) or "Academic Cancer Center" (ACC). Propensity score matching was performed for patient demographics, TNM stage, resection type, and administration of adjuvant chemotherapy. The primary outcome included 30-day mortality, 90-day mortality, and overall survival.There are similar frequencies of radical versus simple resection and administration of adjuvant chemotherapy between ACC and CCC. When propensity-matched for resection type, cases treated at ACC have lower 30-day mortality (4.1% vs. 6.9%) and 90-day mortality (13.2% vs. 18.5%) and increased 5-year overall survival (26.2% vs. 22.4%) (p 0.01). After propensity matching for adjuvant chemotherapy, cases at ACC have lower 30-day mortality (4.12% vs. 7.71%) and 90-day mortality (13.22% vs. 19.19%) and increased overall survival (13.6% vs. 11.0%) (p 0.01).While treatment patterns for gallbladder cancer at ACC and CCC were similar, there was a decrease in 30-day and 90-day mortality and improved overall survival associated with patients treated at ACC. Treatment site may have an impact in the surgical outcomes of gallbladder cancer patients. This disparity warrants further research.
- Published
- 2019
13. Bipolar lophotrichous Helicobacter suis combine extended and wrapped flagella bundles to exhibit multiple modes of motility
- Author
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Maira A, Constantino, Mehdi, Jabbarzadeh, Henry C, Fu, Zeli, Shen, James G, Fox, Freddy, Haesebrouck, Sara K, Linden, and Rama, Bansil
- Subjects
Flagella ,Swine ,Helicobacter heilmannii ,Animals ,Humans ,Models, Biological - Abstract
The swimming strategies of unipolar flagellated bacteria are well known but little is known about how bipolar bacteria swim. Here we examine the motility of Helicobacter suis, a bipolar gastric-ulcer-causing bacterium that infects pigs and humans. Phase-contrast microscopy of unlabeled bacteria reveals flagella bundles in two conformations, extended away from the body (E) or flipped backwards and wrapped (W) around the body. We captured videos of the transition between these two states and observed three different swimming modes in broth: with one bundle rotating wrapped around the body and the other extended (EW), both extended (EE), and both wrapped (WW). Only EW and WW modes were seen in porcine gastric mucin. The EW mode displayed ballistic trajectories while the other two displayed superdiffusive random walk trajectories with slower swimming speeds. Separation into these two categories was also observed by tracking the mean square displacement of thousands of trajectories at lower magnification. Using the Method of Regularized Stokeslets we numerically calculate the swimming dynamics of these three different swimming modes and obtain good qualitative agreement with the measurements, including the decreased speed of the less frequent modes. Our results suggest that the extended bundle dominates the swimming dynamics.
- Published
- 2018
14. Bipolar lophotrichous Helicobacter suis combine extended and wrapped flagella bundles to exhibit multiple modes of motility
- Author
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Maira A. Constantino, Mehdi Jabbarzadeh, Henry C. Fu, Zeli Shen, James G. Fox, Freddy Haesebrouck, Sara K. Linden, and Rama Bansil
- Subjects
3-DIMENSIONAL TRACKING ,lcsh:R ,INSTABILITY ,lcsh:Medicine ,Biology and Life Sciences ,CELL-SHAPE ,REGULARIZED STOKESLETS ,CHEMOTAXIS ,REVERSE ,BACTERIA ,ROTATION ,lcsh:Q ,MICRORHEOLOGY ,lcsh:Science ,human activities ,PARTICLE TRACKING - Abstract
The swimming strategies of unipolar flagellated bacteria are well known but little is known about how bipolar bacteria swim. Here we examine the motility of Helicobacter suis, a bipolar gastric-ulcer-causing bacterium that infects pigs and humans. Phase-contrast microscopy of unlabeled bacteria reveals flagella bundles in two conformations, extended away from the body (E) or flipped backwards and wrapped (W) around the body. We captured videos of the transition between these two states and observed three different swimming modes in broth: with one bundle rotating wrapped around the body and the other extended (EW), both extended (EE), and both wrapped (WW). Only EW and WW modes were seen in porcine gastric mucin. The EW mode displayed ballistic trajectories while the other two displayed superdiffusive random walk trajectories with slower swimming speeds. Separation into these two categories was also observed by tracking the mean square displacement of thousands of trajectories at lower magnification. Using the Method of Regularized Stokeslets we numerically calculate the swimming dynamics of these three different swimming modes and obtain good qualitative agreement with the measurements, including the decreased speed of the less frequent modes. Our results suggest that the extended bundle dominates the swimming dynamics.
- Published
- 2018
15. Person-centred, web-based support in pregnancy and early motherhood for women with Type 1 diabetes mellitus: a randomized controlled trial
- Author
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K, Linden, M, Berg, A, Adolfsson, and C, Sparud-Lundin
- Subjects
Adult ,Glycated Hemoglobin ,Internet ,Adolescent ,Maternal Health ,Pregnancy in Diabetics ,Social Support ,Prenatal Care ,Fear ,Hypoglycemia ,Self Efficacy ,Telemedicine ,Self Care ,Young Adult ,Diabetes Mellitus, Type 1 ,Treatment Outcome ,Pregnancy ,Patient-Centered Care ,Humans ,Female - Abstract
To report results from and explore use of a multicentre, parallel-group, unblinded, randomized controlled trial testing the effectiveness in terms of well-being and diabetes management of a person-centred, web-based support programme for women with Type 1 diabetes, in pregnancy and postpartum.Between 2011 and 2014, 174 pregnant women with Type 1 diabetes were randomly allocated (1:1) to web-based support and standard care (intervention group, n=83), or standard care (control group, n=91). The web-based support consisted of evidence-based information; a self-care diary for monitoring of daily activities; and peer support in a discussion forum. The primary outcomes (mean difference, measured at 6 months after childbirth) were well-being and diabetes management.No differences were found with regard to the primary outcome measure scores for general well-being [1.04 (95% CI -1.28 to 3.37); P=0.68] and self-efficacy of diabetes management [0.08 (95% CI -0.12 to 0.28); P= 0.75], after adjustment for baseline differences in the insulin administration method, nor with regard to the secondary outcome measures.At 6 months after childbirth, the web-based support plus standard care was not superior to standard care in terms of general well-being or self-efficacy of diabetes management. This might be explained by the low number of participants who had a high activity level. Few simultaneously active participants in the web-based programme and stressors in motherhood and diabetes postpartum were the main barriers to its use. Further intervention studies that offer web-based support are needed, with lessons learned from the present study. (Clinicaltrials.gov identification number: NCT015665824).
- Published
- 2017
16. Finnish Dentists Find Smoking Cessation Important but Seldom Offer Practical Support for Their Patients
- Author
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A, Grönholm, D, Litkey, J, Jokelainen, J, Keto, M, Pöyry, K, Linden, and A M, Heikkinen
- Subjects
Male ,Professional Role ,Attitude of Health Personnel ,Dentists ,Humans ,Female ,Smoking Cessation ,Self Report ,Finland ,Dentist-Patient Relations ,Practice Patterns, Dentists' - Abstract
To investigate Finnish dentists' smoking cessation related attitudes, consultation practices and familiarity with the local treatment guideline on smoking cessation.An online questionnaire was sent to 1740 dentists, which corresponds to 39% of dentists in Finland. A total of 456 dentists responded (response rate 26%), of whom 435 (95%) were clinicians. The dentists' smoking cessation practices were also compared to ones reported in a previous study in Finnish physicians.Dentists found smoking cessation important and often discussed and recommended quitting to the patients, but concrete withdrawal actions were seldom provided. The local treatment guideline on smoking cessation was actively utilized by 36% of the dentists. Adherence to the guideline was associated with higher rates of smoking cessation activities and success in them. Smoking cessation activity among dentists was significantly lower than in Finnish physicians. In accordance with the literature, among dentists, the most common barriers for smoking cessation were lack of time (44%) and education (42%).Although smoking cessation is discussed with patients, dentists are less active in taking concrete actions to support the patient on withdrawal. Adherence to the local treatment guideline was associated with better capabilities in dealing with tobacco withdrawal and a more active role in smoking cessation. The results suggest that more education on the local smoking cessation treatment guideline and cessation intervention is needed in order to overcome the remaining barriers to promoting effective smoking cessation in dental practice.
- Published
- 2017
17. Update on the MiniCLEAN Dark Matter Experiment
- Author
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E. Grace, Daniel McKinsey, R. Bourque, Jeff Griego, Jocelyn Monroe, S. Jaditz, I. T. Lawson, B. Wang, Y. Chen, Joseph A. Formaggio, Kevin J. Coakley, F. Giuliani, G. D. Orebi Gann, J. R. Klein, C. Kachulis, S. Seibert, E. Kearns, S. MacMullin, B. Buck, Keith Rielage, G. Perumpilly, John A. Oertel, K. J. Palladino, V. E. Guiseppe, A. LaTorre, Chao Zhang, E. Flores, J. Kelsey, J. Walding, M. Akashi-Ronquest, Natalia Guerrero, A. Hime, James Nikkel, M. Bodmer, Reyco Henning, A. Mastbaum, A. Butcher, J. Wang, Dongming Mei, T. Caldwell, S. K. Linden, D. Gastler, L. Rodriguez, Michael Gold, F. E. Lopez, R. W. Schnee, Massachusetts Institute of Technology. Department of Physics, MIT Kavli Institute for Astrophysics and Space Research, Buck, Benjamin R., Formaggio, Joseph A, Kelsey, James E, and Guerrero, Natalia M.
- Subjects
Photomultiplier ,Physics - Instrumentation and Detectors ,WIMP ,Physics::Instrumentation and Detectors ,Dark matter ,chemistry.chemical_element ,FOS: Physical sciences ,Physics and Astronomy(all) ,dark matter ,High Energy Physics - Experiment ,Nuclear physics ,Neon ,High Energy Physics - Experiment (hep-ex) ,Recoil ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Physics ,Scintillation ,Argon ,scintillation ,Detector ,liquid neon ,Instrumentation and Detectors (physics.ins-det) ,liquid argon ,chemistry ,solar neutrinos ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The direct search for dark matter is entering a period of increased sensitivity to the hypothetical Weakly Interacting Massive Particle (WIMP). One such technology that is being examined is a scintillation only noble liquid experiment, MiniCLEAN. MiniCLEAN utilizes over 500 kg of liquid cryogen to detect nuclear recoils from WIMP dark matter and serves as a demonstration for a future detector of order 50 to 100 tonnes. The liquid cryogen is interchangeable between argon and neon to study the A2 dependence of the potential signal and examine backgrounds. MiniCLEAN utilizes a unique modular design with spherical geometry to maximize the light yield using cold photomultiplier tubes in a single-phase detector. Pulse shape discrimination techniques are used to separate nuclear recoil signals from electron recoil backgrounds. MiniCLEAN will be spiked with additional 39Ar to demonstrate the effective reach of the pulse shape discrimination capability. Assembly of the experiment is underway at SNOLAB and an update on the project is given., Los Alamos National Laboratory, United States. Department of Energy. Office of Science, National Science Foundation (U.S.), National Institute of Standards and Technology (U.S.)
- Published
- 2015
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18. 26 Use of a one hour high sensitivity troponin t measurement in the initial assessment of patients presenting with cardiac chest pain to emergency departments in the belfast trust
- Author
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L Swales, N Johnston, G McKeeman, P Shortt, K Linden, M Carleton, J Collins, and S Davenport
- Subjects
medicine.medical_specialty ,biology ,business.industry ,Chest pain ,High Sensitivity Troponin T ,medicine.disease ,Triage ,Troponin ,Emergency medicine ,medicine ,biology.protein ,Myocardial infarction ,Cardiac chest pain ,medicine.symptom ,Medical diagnosis ,business ,Mace - Abstract
Aims To establish the safety and efficacy of a rapid one hour chest pain pathway using high sensitivity troponin T (HsTnT) to triage patients presenting with cardiac sounding chest pain to Emergency Departments (ED) in the Belfast Health and Social Care Trust (BHSCT). Methods Recent ESC guidelines support the use of HsTnT and a one hour pathway to safely “rule out” myocardial infarction (MI) in patients presenting to the ED with suspected cardiac chest pain. After an initial pilot study the BHSCT implemented a one hour pathway in July 2016 incorporating results of HsTnT levels at presentation and one hour, patient risk assessment and 12 lead ECG. Based on this the pathway triaged patients to a “rule out MI”, “observation” or “rule in MI” group. After introduction follow up data was collected on every patient presenting with chest pain between 1st July 2016 and 30th September 2016 to both ED’s within the BHSCT. Follow up data on final diagnosis, MACE, re-presentation to the ED and mortality was collected for a period of six months. Results Of the 1,454 patients included in the analysis (see figure 1) 594 (41%) were female and the average age was 62. 1,041 (71.6%) patients were triaged to the rule out group and there were no new cardiac diagnoses in this group at 90 days and no cardiac deaths at 6 months. 326 (22.4%) patients were triaged to the “observation” group and there were 4 (1.2%) cardiac deaths in this group at 6 months. Within the observation group a further 42 patients were diagnosed with MI (13% of observation group). 87 (6.0%) patients were triaged to the “rule in” group where 65 (74.7%) had a diagnosis of NSTEMI and 90% had a diagnosis requiring admission under cardiology. There were 6 (6.9%) cardiac deaths in the “rule in” group at 6 months. The negative predictive value for the rule out group was 99.6% and sensitivity 90.1%. The positive predictive value for the rule in group was 84% with a specificity for a cardiac diagnosis of 98.6%. Conclusion Implementation of a one hour troponin pathway in conjunction with clinical assessment is accurate and safe. Using the pathway meant that 77% of patients could be rapidly ruled ‘out’ or ‘in’ using the one hour pathway enabling timely decision making in the ED and safe discharge for 71% patients. In those patients for whom acute MI was ruled out, there were no cardiac deaths after six months follow up.
- Published
- 2017
19. Modellierung von PV Loops für LV basierend auf 3D-Echokardiografie
- Author
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J Breuer, K Linden, F Recker, U Herberg, and C. Winkler
- Published
- 2017
20. Incidence, prevalence, and management of MRSA bacteremia across patient populations—a review of recent developments in MRSA management and treatment
- Author
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Peter K. Linden, Ali Hassoun, and Bruce Friedman
- Subjects
0301 basic medicine ,Methicillin-Resistant Staphylococcus aureus ,medicine.medical_specialty ,Staphylococcus aureus ,medicine.drug_class ,Epidemiology ,030106 microbiology ,Antibiotics ,Prevalence ,Bacteremia ,Review ,MRSA ,MSSA ,Critical Care and Intensive Care Medicine ,medicine.disease_cause ,03 medical and health sciences ,Medicine ,Humans ,Intensive care medicine ,business.industry ,Incidence (epidemiology) ,Incidence ,lcsh:Medical emergencies. Critical care. Intensive care. First aid ,lcsh:RC86-88.9 ,biochemical phenomena, metabolism, and nutrition ,medicine.disease ,bacterial infections and mycoses ,Methicillin-resistant Staphylococcus aureus ,Management ,Anti-Bacterial Agents ,030104 developmental biology ,Infective endocarditis ,business - Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) infection is still a major global healthcare problem. Of concern is S. aureus bacteremia, which exhibits high rates of morbidity and mortality and can cause metastatic or complicated infections such as infective endocarditis or sepsis. MRSA is responsible for most global S. aureus bacteremia cases, and compared with methicillin-sensitive S. aureus, MRSA infection is associated with poorer clinical outcomes. S. aureus virulence is affected by the unique combination of toxin and immune-modulatory gene products, which may differ by geographic location and healthcare- or community-associated acquisition. Management of S. aureus bacteremia involves timely identification of the infecting strain and source of infection, proper choice of antibiotic treatment, and robust prevention strategies. Resistance and nonsusceptibility to first-line antimicrobials combined with a lack of equally effective alternatives complicates MRSA bacteremia treatment. This review describes trends in epidemiology and factors that influence the incidence of MRSA bacteremia. Current and developing diagnostic tools, treatments, and prevention strategies are also discussed.
- Published
- 2017
21. Pumpless extracorporeal CO2removal restores normocapnia and is associated with less regional perfusion in experimental acute lung injury
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R. Tolba, Jörg Zinserling, Thomas Muders, Dirk Varelmann, Christian Putensen, K. Linden, Hermann Wrigge, C. Kricklies, H. Luepschen, and Stefan Kreyer
- Subjects
Cardiac output ,business.industry ,Metabolic acidosis ,General Medicine ,Blood flow ,Lung injury ,medicine.disease ,Extracorporeal ,Hypoventilation ,Anesthesiology and Pain Medicine ,Anesthesia ,Medicine ,Normocapnia ,medicine.symptom ,business ,Perfusion - Abstract
Background Lung protective ventilation may lead to hypoventilation with subsequent hypercapnic acidosis (HA). If HA cannot be tolerated or occurs despite increasing respiratory rate or buffering, extracorporeal CO2-removal using a percutaneous extracorporeal lung assist (pECLA) is an option. We hypothesised that compensation of HA using pECLA impairs regional perfusion. To test this hypothesis we determined organ blood flows in a lung-injury model with combined hypercapnic and metabolic acidosis. Methods After induction of lung injury using hydrochloric acid (HCl) aspiration and metabolic acidosis by intravenous HCl infusion in nine pigs, an arterial-venous pECLA device was inserted. In randomised order, four treatments were tested: pECLA shunt (1) with and (2) without HA, and clamped pECLA shunt (3) with and (4) without HA. Regional blood flows were measured with the coloured microsphere technique. Results HA resulted in higher perfusion in adrenal glands, spleen and parts of splanchnic area (P
- Published
- 2013
22. 3D Real-Time Echocardiography Combined with Mini Pressure Wire Generate Reliable Pressure-Volume Loops in Small Hearts
- Author
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Georg D. Duerr, Dennis Ladage, Matthias Seehase, K. Linden, Oliver Dewald, Ulrike Herberg, Jonas Dörner, Stephanie Kleppe, Johannes Breuer, Eva Gatzweiler, and Guo, Yiru
- Subjects
Swine ,medicine.medical_treatment ,Hemodynamics ,lcsh:Medicine ,Blood Pressure ,030204 cardiovascular system & hematology ,Vascular Medicine ,Diagnostic Radiology ,0302 clinical medicine ,Ultrasound Imaging ,Medicine and Health Sciences ,Morphogenesis ,030212 general & internal medicine ,lcsh:Science ,Cardiac catheterization ,Mammals ,Multidisciplinary ,medicine.diagnostic_test ,Radiology and Imaging ,Heart ,Agriculture ,Hematology ,Congenital Heart Defects ,Esmolol ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Echocardiography ,Vertebrates ,Cardiology ,Ventricular pressure ,Anatomy ,medicine.drug ,Research Article ,Biotechnology ,Cardiac function curve ,medicine.medical_specialty ,Catheters ,Livestock ,Cardiac Ventricles ,Imaging Techniques ,Heart Ventricles ,Diastole ,Blood pressure ,Cardiac ventricles ,Congenital heart defects ,Research and Analysis Methods ,03 medical and health sciences ,Cardiac magnetic resonance imaging ,Diagnostic Medicine ,Internal medicine ,medicine ,Pressure ,Congenital Disorders ,Animals ,Birth Defects ,business.industry ,lcsh:R ,Organisms ,Biology and Life Sciences ,Amniotes ,Vascular resistance ,Cardiovascular Anatomy ,lcsh:Q ,Medical Devices and Equipment ,business ,Developmental Biology - Abstract
BACKGROUND: Pressure-volume loops (PVL) provide vital information regarding ventricular performance and pathophysiology in cardiac disease. Unfortunately, acquisition of PVL by conductance technology is not feasible in neonates and small children due to the available human catheter size and resulting invasiveness. The aim of the study was to validate the accuracy of PVL in small hearts using volume data obtained by real-time three-dimensional echocardiography (3DE) and simultaneously acquired pressure data. METHODS: In 17 piglets (weight range: 3.6–8.0 kg) left ventricular PVL were generated by 3DE and simultaneous recordings of ventricular pressure using a mini pressure wire (PVL3D). PVL3D were compared to conductance catheter measurements (PVLCond) under various hemodynamic conditions (baseline, alpha-adrenergic stimulation with phenylephrine, beta-adrenoreceptor-blockage using esmolol). In order to validate the accuracy of 3D volumetric data, cardiac magnetic resonance imaging (CMR) was performed in another 8 piglets. RESULTS: Correlation between CMR- and 3DE-derived volumes was good (enddiastolic volume: mean bias -0.03ml ±1.34ml). Computation of PVL3D in small hearts was feasible and comparable to results obtained by conductance technology. Bland-Altman analysis showed a low bias between PVL3D and PVLCond. Systolic and diastolic parameters were closely associated (Intraclass-Correlation Coefficient for: systolic myocardial elastance 0.95, arterial elastance 0.93, diastolic relaxation constant tau 0.90, indexed end-diastolic volume 0.98). Hemodynamic changes under different conditions were well detected by both methods (ICC 0.82 to 0.98). Inter- and intra-observer coefficients of variation were below 5% for all parameters. CONCLUSIONS: PVL3D generated from 3DE combined with mini pressure wire represent a novel, feasible and reliable method to assess different hemodynamic conditions of cardiac function in hearts comparable to neonate and infant size. This methodology may be integrated into clinical practice and cardiac catheterization programs and has the capability to contribute to clinical decision making even in small hearts.
- Published
- 2016
23. Comparison of stroke volumes assessed by three-dimensional echocardiography and transpulmonary thermodilution in a pediatric animal model
- Author
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Eva Gatzweiler, Dennis Ladage, Oliver Dewald, Matthias Seehase, Georg D. Duerr, Johannes Breuer, Andrea Pieper, K. Linden, and Ulrike Herberg
- Subjects
medicine.medical_specialty ,Time Factors ,Correlation coefficient ,Swine ,Systole ,Thermodilution ,Echocardiography, Three-Dimensional ,Hemodynamics ,Health Informatics ,030204 cardiovascular system & hematology ,Critical Care and Intensive Care Medicine ,Pediatrics ,Ventricular Function, Left ,Propanolamines ,03 medical and health sciences ,Phenylephrine ,Ventricular Dysfunction, Left ,0302 clinical medicine ,Animal model ,Heart Rate ,Internal medicine ,Heart rate ,medicine ,Animals ,Stroke ,Observer Variation ,business.industry ,Reproducibility of Results ,030208 emergency & critical care medicine ,Heart ,Stroke Volume ,Stroke volume ,Esmolol ,medicine.disease ,Anesthesiology and Pain Medicine ,Anesthesia ,Models, Animal ,Cardiology ,Female ,business ,medicine.drug - Abstract
To compare stroke volumes (SV) in small hearts assessed by real-time three-dimensional echocardiography (3DE) with SV measured by transpulmonary thermodilution (TPTD) and continuous pulse contour analysis (PC) under various hemodynamic conditions. In thirteen anesthetized piglets (range 3.6-7.1 kg) SV were measured by 3DE, TPTD and PC at baseline and during phenylephrine and esmolol administration. 3DE and TPTD measurements were done successively while SV calculated by PC was documented at the time of 3DE. 3DE and TPTD showed a good correlation (r2 = 0.74) and a bias of -1.3 ml (limits of agreement -4.1 to 1.5 ml). While TPTD measured higher SV than 3DE, both methods tracked SV changes with a concordance rate of 91 %. PC and 3DE showed a lower correlation coefficient of r2 = 0.57 and a bias of -2.1 ml (limits of agreement -5.9 to 1.8 ml). Inter- and intra-observer variability of SV measured by 3DE was good with a mean bias
- Published
- 2015
24. Voriconazole Pharmacokinetics in Liver Transplant Recipients
- Author
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Blair Capitano, Kelong Han, D. Blisard, M. Romkes, Amadeo Marcos, Peter K. Linden, H. J. Johnson, Shahid Husain, Brian A. Potoski, Raman Venkataramanan, David L. Paterson, and Eun J. Kwak
- Subjects
Adult ,Male ,medicine.medical_specialty ,Antifungal Agents ,Genotype ,Aspartate transaminase ,Pharmacology ,Gastroenterology ,Pharmacokinetics ,Internal medicine ,medicine ,Aspergillosis ,Humans ,Pharmacology (medical) ,Trough Concentration ,Prospective Studies ,Aged ,Volume of distribution ,Voriconazole ,biology ,Chemistry ,Middle Aged ,Triazoles ,Liver Transplantation ,Bioavailability ,Pyrimidines ,Infectious Diseases ,Area Under Curve ,biology.protein ,Trough level ,Female ,Liver function ,medicine.drug - Abstract
The objective of this study was to evaluate the pharmacokinetics of voriconazole and the potential correlations between pharmacokinetic parameters and patient variables in liver transplant patients on a fixed-dose prophylactic regimen. Multiple blood samples were collected within one dosing interval from 15 patients who were initiated on a prophylactic regimen of voriconazole at 200 mg enterally (tablets) twice daily starting immediately posttransplant. Voriconazole plasma concentrations were measured using high-pressure liquid chromatography (HPLC). Noncompartmental pharmacokinetic analysis was performed to estimate pharmacokinetic parameters. The mean apparent systemic clearance over bioavailability (CL/ F ), apparent steady-state volume of distribution over bioavailability ( V ss / F ), and half-life ( t 1/2 ) were 5.8 ± 5.5 liters/h, 94.5 ± 54.9 liters, and 15.7 ± 7.0 h, respectively. There was a good correlation between the area under the concentration-time curve from 0 h to infinity (AUC 0-∞ ) and trough voriconazole plasma concentrations. t 1/2 , maximum drug concentration in plasma ( C max ), trough level, AUC 0-∞ , area under the first moment of the concentration-time curve from 0 h to infinity (AUMC 0-∞ ), and mean residence time from 0 h to infinity (MRT 0-∞ ) were significantly correlated with postoperative time. t 1/2 , λ, AUC 0-∞ , and CL/ F were significantly correlated with indices of liver function (aspartate transaminase [AST], total bilirubin, and international normalized ratio [INR]). The C max , last concentration in plasma at 12 h ( C last ), AUMC 0-∞ , and MRT 0-∞ were significantly lower in the presence of deficient CYP2C19*2 alleles. Donor characteristics had no significant correlation with any of the pharmacokinetic parameters estimated. A fixed dosing regimen of voriconazole results in a highly variable exposure of voriconazole in liver transplant patients. Given that trough voriconazole concentration is a good measure of drug exposure (AUC), the voriconazole dose can be individualized based on trough concentration measurements in liver transplant patients.
- Published
- 2010
25. History of Solid Organ Transplantation and Organ Donation
- Author
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Peter K. Linden
- Subjects
medicine.medical_specialty ,Tissue and Organ Procurement ,Critical Care ,medicine.medical_treatment ,Liver transplantation ,Global Health ,Critical Care and Intensive Care Medicine ,History, 21st Century ,Tacrolimus ,Organ transplantation ,medicine ,Animals ,Humans ,Lung transplantation ,Organ donation ,Intensive care medicine ,History, Ancient ,Kidney transplantation ,Immunosuppression Therapy ,Heart transplantation ,business.industry ,Histocompatibility Testing ,Immunosuppression ,Organ Transplantation ,General Medicine ,History, 20th Century ,medicine.disease ,Kidney Transplantation ,United States ,Liver Transplantation ,Surgery ,Models, Animal ,Cyclosporine ,Heart Transplantation ,Pancreas Transplantation ,business ,Solid organ transplantation ,Immunosuppressive Agents ,Lung Transplantation - Abstract
Solid organ transplantation is one of the most remarkable and dramatic therapeutic advances in medicine during the past 60 years. This field has progressed initially from what can accurately be termed a "clinical experiment" to routine and reliable practice, which has proven to be clinically effective, life-saving and cost-effective. This remarkable evolution stems from a serial confluence of: cultural acceptance; legal and political evolution to facilitate organ donation, procurement and allocation; technical and cognitive advances in organ preservation, surgery, immunology, immunosuppression; and management of infectious diseases. Some of the major milestones of this multidisciplinary clinical science are reviewed in this article.
- Published
- 2009
26. Vancomycin resistance: are there better glycopeptides coming?
- Author
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Peter K. Linden
- Subjects
Microbiology (medical) ,medicine.medical_specialty ,Microbial Sensitivity Tests ,Gram-Positive Bacteria ,medicine.disease_cause ,Microbiology ,Antibiotic resistance ,Telavancin ,Vancomycin ,Virology ,medicine ,Humans ,Intensive care medicine ,Gram-Positive Bacterial Infections ,Clinical Trials as Topic ,biology ,Teicoplanin ,business.industry ,Oritavancin ,Glycopeptides ,Dalbavancin ,Vancomycin Resistance ,biochemical phenomena, metabolism, and nutrition ,biology.organism_classification ,Anti-Bacterial Agents ,Infectious Diseases ,Enterococcus ,Staphylococcus aureus ,business ,medicine.drug - Abstract
The appearance and dissemination of vancomycin resistance among clinically important Gram-positive bacteria was an important watershed in antimicrobial resistance trends that drastically narrows therapeutic options, particularly among the enterococci. Clinical resistance despite apparent susceptibility has also become an increasingly recognized issue with vancomycin treatment of methicillin-resistant Staphylococcus aureus pneumonia and endocarditis, which may be, in part, due to vancomycin-heteroresistant strains. The newly developed glycopeptides telavancin, dalbavancin and oritavancin have superior in vitro activity, enhanced bactericidality and unique pharmacokinetic properties compared with vancomycin and teicoplanin. Current clinical trial data show noninferiority to vancomycin or standard-of-care antistaphylococcal therapy for complicated skin-skin structure infections, and acceptable safety profiles. Although promising, whether or not these new compounds are clinically efficacious for the true therapeutic deficits created by in vitro and clinical vancomycin resistance is yet to be determined.
- Published
- 2008
27. Health Care–Associated Infection (HAI): A Critical Appraisal of the Emerging Threat—Proceedings of the HAI Summit
- Author
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In-Gyu Bae, Peter K. Linden, Lena M. Napolitano, Dennis L. Stevens, Richard G. Wunderink, Vance G. Fowler, Scott T. Micek, James J. Rahal, Robert A. Balk, Marin H. Kollef, Andrew F. Shorr, and Joseph S. Solomkin
- Subjects
Microbiology (medical) ,Healthcare associated infections ,medicine.medical_specialty ,animal structures ,Health care associated ,Antibiotic therapy ,Prevalence ,medicine ,Humans ,Intensive care medicine ,Cross Infection ,Infection Control ,geography ,Summit ,geography.geographical_feature_category ,business.industry ,virus diseases ,Bacterial Infections ,medicine.disease ,Pathogenic organism ,Quality of evidence ,Pneumonia ,Critical appraisal ,Infectious Diseases ,Mycoses ,business - Abstract
During the Health Care-Associated Pneumonia Summit conducted in June 2007, it was found that there is a need for educational efforts in several areas of health care-associated infections (HAI) that extend beyond pneumonia. This supplement to Clinical Infectious Diseases represents the proceedings of the HAI Summit, a diverse panel of clinical investigators whose goal was to assess the quality of evidence regarding issues surrounding HAI and to discuss potential implications for its diagnosis and treatment in the future.
- Published
- 2008
28. Noninvasive monitoring of cerebral perfusion pressure in patients with acute liver failure using transcranial doppler ultrasonography
- Author
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S Aggarwal, John F. Patzer, David M. Brooks, Peter K. Linden, and Yoogoo Kang
- Subjects
Adult ,Male ,Middle Cerebral Artery ,medicine.medical_specialty ,Adolescent ,Intracranial Pressure ,Ultrasonography, Doppler, Transcranial ,Diastole ,Blood Pressure ,Internal medicine ,medicine ,Humans ,Waveform ,Cerebral perfusion pressure ,Systole ,Aged ,Retrospective Studies ,Intracranial pressure ,Transplantation ,Hepatology ,business.industry ,musculoskeletal, neural, and ocular physiology ,Windkessel effect ,Liver Failure, Acute ,Middle Aged ,Blood pressure ,Cerebral blood flow ,Cerebrovascular Circulation ,Anesthesia ,cardiovascular system ,Cardiology ,Female ,Surgery ,business - Abstract
Elevated intracranial pressure (ICP) leads to loss of cerebral perfusion, cerebral herniation, and irreversible brain damage in patients with acute liver failure (ALF). Conventional techniques for monitoring ICP can be complicated by hemorrhage and infection. Transcranial doppler ultrasonography (TCD) is a noninvasive device which can continuously measure cerebral blood flow velocity, producing a velocity-time waveform that indirectly monitors changes in cerebral hemodynamics, including ICP. The primary goal of this study was to determine whether TCD waveform features could be used to differentiate ALF patients with respect to ICP or, equally important, cerebral perfusion pressure (CPP) levels. A retrospective study of 16 ALF subjects with simultaneous TCD, ICP, and CPP measurements yielded a total of 209 coupled ICP-CPP-TCD observations. The TCD waveforms were digitally scanned and seven points corresponding to a simplified linear waveform were identified. TCD waveform features including velocity, pulsatility index, resistive index, fraction of the cycle in systole, slopes, and angles associated with changes in the slope in each region, were calculated from the simplified waveform data. Paired ICP-TCD observations were divided into three groups (ICP20 mmHg, n = 102; 20or = ICP30 mmHg, n = 74; and ICPor = 30 mmHg, n = 33). Paired CPP-TCD observations were also divided into three groups (CPPor = 80 mmHg, n = 42; 80CPPor = 60 mmHg, n = 111; and CPP60 mmHg, n = 56). Stepwise linear discriminant analysis was used to identify TCD waveform features that discriminate between ICP groups and CPP groups. Four primary features were found to discriminate between ICP groups: the blood velocity at the start of the Windkessel effect, the slope of the Windkessel upstroke, the angle between the end systolic downstroke and start diastolic upstroke, and the fraction of time spent in systole. Likewise, 4 features were found to discriminate between the CPP groups: the slope of the Windkessel upstroke, the slope of the Windkessel downstroke, the slope of the diastolic downstroke, and the angle between the end systolic downstroke and start diastolic upstroke. The TCD waveform captures the cerebral hemodynamic state and can be used to predict dynamic changes in ICP or CPP in patients with ALF. The mean TCD waveforms for corresponding, correctly classified ICP and CPP groups are remarkably similar. However, this approach to predicting intracranial hypertension and CPP needs to be further refined and developed before clinical application is feasible.
- Published
- 2008
29. Guidelines for evaluation of new fever in critically ill adult patients: 2008 update from the American College of Critical Care Medicine and the Infectious Diseases Society of America
- Author
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David M. Nierman, Karen C. Carroll, Naomi P. O'Grady, Andre C. Kalil, John G. Bartlett, Henry Masur, William Pasculle, Dennis G. Maki, Peter K. Linden, Philip S. Barie, and Thomas P. Bleck
- Subjects
Adult ,medicine.medical_specialty ,Neurology ,Critical Care ,Fever ,MEDLINE ,Medical laboratory ,Critical Care and Intensive Care Medicine ,Communicable Diseases ,Body Temperature ,Scientific evidence ,law.invention ,law ,Intensive care ,Nominal group technique ,medicine ,Humans ,Intensive care medicine ,Societies, Medical ,Randomized Controlled Trials as Topic ,Cross Infection ,business.industry ,Intensive care unit ,United States ,Intensive Care Units ,Etiology ,business - Abstract
Objective: To update the practice parameters for the evaluation of adult patients who develop a new fever in the intensive care unit, for the purpose of guiding clinical practice. Participants: A task force of 11 experts in the disciplines related to critical care medicine and infectious diseases was convened from the membership of the Society of Critical Care Medicine and the Infectious Diseases Society of America. Specialties represented included critical care medicine, surgery, internal medicine, infectious diseases, neurology, and laboratory medicine/microbiology. Evidence: The task force members provided personal experience and determined the published literature (MEDLINE articles, textbooks, etc.) from which consensus was obtained. Published literature was reviewed and classified into one of four categories, according to study design and scientific value. Consensus Process: The task force met twice in person, several times by teleconference, and held multiple e-mail discussions during a 2-yr period to identify the pertinent literature and arrive at consensus recommendations. Consideration was given to the relationship between the weight of scientific evidence and the strength of the recommendation. Draft documents were composed and debated by the task force until consensus was reached by nominal group process. Conclusions: The panel concluded that, because fever can have many infectious and noninfectious etiologies, a new fever in a patient in the intensive care unit should trigger a careful clinical assessment rather than automatic orders for laboratory and radiologic tests. A cost-conscious approach to obtaining cultures and imaging studies should be undertaken if indicated after a clinical evaluation. The goal of such an approach is to determine, in a directed manner, whether infection is present so that additional testing can be avoided and therapeutic decisions can be made. (Crit Care Med 2008; 36:1330‐1349)
- Published
- 2008
30. Acquisition of Rectal Colonization by Vancomycin-Resistant Enterococcus among Intensive Care Unit Patients Treated with Piperacillin-Tazobactam versus Those Receiving Cefepime-Containing Antibiotic Regimens
- Author
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Brian A. Potoski, David L. Paterson, David C. Aron, Blair Capitano, Carlene A. Muto, Peter K. Linden, Magdaline Ndirangu, Curtis J. Donskey, and Robert A. Bonomo
- Subjects
Male ,medicine.medical_specialty ,medicine.drug_class ,Cefepime ,Antibiotics ,Penicillanic Acid ,Microbial Sensitivity Tests ,Clinical Therapeutics ,medicine.disease_cause ,Tazobactam ,law.invention ,law ,Internal medicine ,polycyclic compounds ,medicine ,Humans ,Pharmacology (medical) ,Vancomycin-resistant Enterococcus ,Gram-Positive Bacterial Infections ,Aged ,Antibacterial agent ,Piperacillin ,Pharmacology ,business.industry ,Rectum ,Vancomycin Resistance ,Middle Aged ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,Intensive care unit ,Anti-Bacterial Agents ,Cephalosporins ,Culture Media ,Surgery ,Intensive Care Units ,Piperacillin, Tazobactam Drug Combination ,Infectious Diseases ,Piperacillin/tazobactam ,Female ,business ,Enterococcus ,medicine.drug - Abstract
In contrast to expanded-spectrum cephalosporins, beta-lactam-beta-lactamase inhibitor combinations such as piperacillin-tazobactam have rarely been associated with vancomycin-resistant Enterococcus (VRE) colonization and infection. In mice, piperacillin-tazobactam has sufficient antienterococcal activity to inhibit the establishment of colonization during treatment, but this effect has not been confirmed in human patients. We prospectively evaluated the acquisition of rectal colonization by VRE among intensive care unit patients receiving antibiotic regimens containing piperacillin-tazobactam versus those receiving cefepime, an expanded-spectrum cephalosporin with minimal antienterococcal activity. Rectal swabs were obtained weekly and were cultured for VRE. For 146 patients with a negative rectal swab for VRE prior to therapy, there was no significant difference in the frequency of VRE acquisition between patients receiving piperacillin-tazobactam- and cefepime-containing regimens (19/72 [26.4%] and 23/74 [31.1%], respectively; P = 0.28). Of the 19 patients who acquired VRE in association with piperacillin-tazobactam, 10 (53%) developed the new detection of VRE during therapy. Patients initiated on treatment with cefepime-containing regimens were significantly more likely than those initiated on treatment with piperacillin-tazobactam-containing regimens to have received antibiotic therapy in the prior 30 days (55/74 [74.3%] and 22/72 [30.6%], respectively; P < 0.001). These findings suggest that piperacillin-tazobactam- and cefepime-containing antibiotic regimens may be associated with the frequent acquisition of VRE in real-world intensive care unit settings. Although piperacillin-tazobactam inhibits the establishment of VRE colonization in mice when exposure occurs during treatment, our data suggest that this agent may not prevent the acquisition of VRE in patients.
- Published
- 2008
31. Optimizing Therapy for Vancomycin-Resistant Enterococci (VRE)
- Author
-
Peter K. Linden
- Subjects
Pulmonary and Respiratory Medicine ,Drug resistance ,Tigecycline ,Critical Care and Intensive Care Medicine ,Microbiology ,chemistry.chemical_compound ,Antibiotic resistance ,Anti-Infective Agents ,Vancomycin ,Ampicillin ,Acetamides ,polycyclic compounds ,medicine ,Humans ,Gram-Positive Bacterial Infections ,Oxazolidinones ,Cross Infection ,biology ,business.industry ,Linezolid ,Drug Resistance, Microbial ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,biology.organism_classification ,Anti-Bacterial Agents ,Enterococcus ,chemistry ,Daptomycin ,business ,medicine.drug - Abstract
Enterococci are gram-positive, facultative bacteria with low intrinsic virulence but capable of causing a diverse variety of infections such as bacteremia with or without endocarditis, and intra-abdominal, wound, and genitourinary infection. During the past 2 decades the incidence of hospital-acquired enterococcal infection has significantly risen and is increasingly due to multidrug-resistant strains, primarily to the coacquisition of genetic determinants that encode for the stable expression of high-level beta-lactam, aminoglycoside, and glycopeptide resistance. Because enterococci constitute part of the normal colonizing flora, careful clinical interpretation of cultures that grow enterococci is paramount to avoid unnecessary and potentially deleterious antimicrobial therapy. Traditional antimicrobial treatment for ampicillin- and glycopeptide-susceptible enterococcal infection remains a penicillin-, ampicillin-, semisynthetic penicillin-based regimen, or vancomycin in a penicillin-intolerant individual. The need for a bactericidal combination with a cell-wall active agent combined with an aminoglycoside is most supported for native- or prosthetic valve endocarditis but is unproven for the majority of infections due to enterococci. The emergence of vancomycin-resistant enterococci prompted the clinical development of several novel and modified antimicrobial compounds approved for VRE infection (quinupristin-dalfopristin, linezolid) and several approved for non-VRE indications (daptomycin, tigecycline). There is a paucity of comparative clinical trial data with these new agents, although linezolid, based upon its efficacy and tolerability, appears to be the cornerstone of current treatment approaches. Despite a relatively short period of clinical use, enterococcal resistance has now been described for quinupristin-dalfopristin and linezolid and more recently even for daptomycin and tigecycline. Moreover, the optimal treatment of endocarditis due to VRE strains is unknown because, with the exception of daptomycin, current treatment options only yield bacteriostasis. Nonantimicrobial measures to treat VRE infection, such as foreign body removal and percutaneous or surgical drainage of close-spaced infection, reduce both the need for and the duration of anti-enterococcal treatment and the emergence of resistance to the newer antimicrobials.
- Published
- 2007
32. Pseudomonas aeruginosa infections in the Intensive Care Unit: can the adequacy of empirical β-lactam antibiotic therapy be improved?
- Author
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Kathleen A. Shutt, David L. Paterson, Shigeki Fujitani, Blair Capitano, Brian A. Potoski, Peter K. Linden, and Sunil V Bhat
- Subjects
Microbiology (medical) ,medicine.medical_specialty ,medicine.drug_class ,Cefepime ,Antibiotics ,beta-Lactams ,medicine.disease_cause ,Tazobactam ,law.invention ,Risk Factors ,law ,Drug Resistance, Bacterial ,medicine ,Humans ,Pseudomonas Infections ,Pharmacology (medical) ,Intensive care medicine ,Amikacin ,Retrospective Studies ,Cross Infection ,Pseudomonas aeruginosa ,business.industry ,General Medicine ,Intensive care unit ,Anti-Bacterial Agents ,Intensive Care Units ,Infectious Diseases ,Drug Therapy, Combination ,business ,Empiric therapy ,Algorithms ,medicine.drug ,Piperacillin - Abstract
Inadequate empirical antibiotic therapy for serious Pseudomonas aeruginosa infections has been linked to increased mortality. We performed a retrospective cohort study of consecutive patients with ventilator-associated pneumonia, bacteraemia or other sterile-site infections caused by P. aeruginosa occurring during Intensive Care Unit admissions. One hundred and fifty-eight episodes of serious infection with P. aeruginosa occurred in 140 patients. Empirical antibiotic therapy was microbiologically adequate in 67% of episodes of infection. Patients with P. aeruginosa isolates resistant to piperacillin/tazobactam or cefepime were more likely to have received these antibiotics in the month prior to the P. aeruginosa infection or to have had a Gram-negative bacillus resistant to these antibiotics isolated in the month prior to the P. aeruginosa infection. From these data, we have developed simple algorithms for empirical antibiotic choice in seriously ill patients with suspected P. aeruginosa infections based on prior antibiotic exposure and prior isolation of antibiotic-resistant organisms. Application of these algorithms would have improved the adequacy of empirical antibiotic therapy from 67% to 80-84%. Routine empirical addition of amikacin to the beta-lactam would have increased the adequacy of the antibiotics to 96%. We conclude that knowledge of the prior receipt of beta-lactam antibiotics with activity against P. aeruginosa and the isolation of Gram-negative bacilli resistant to such antibiotics in the recent past can readily increase the adequacy of empirical antibiotic therapy for suspected P. aeruginosa infections.
- Published
- 2007
33. Safety Profile of Meropenem
- Author
-
Peter K. Linden
- Subjects
medicine.medical_specialty ,Imipenem ,Carbapenem ,Toxicology ,Meropenem ,Internal medicine ,polycyclic compounds ,medicine ,Humans ,Pharmacology (medical) ,Intensive care medicine ,Adverse effect ,Antibacterial agent ,Pharmacology ,Clinical Trials as Topic ,Cilastatin ,business.industry ,Clindamycin ,Bacterial Infections ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,medicine.disease ,Anti-Bacterial Agents ,Thienamycins ,business ,Meningitis ,medicine.drug - Abstract
Meropenem is a broad-spectrum carbapenem antibacterial with potent antimicrobial activity against a broad range of Gram-negative, Gram-positive and anaerobic bacteria. The second parenteral carbapenem to be introduced worldwide, meropenem has been in clinical use since 1994. Two previous safety reviews have established that meropenem has a favourable and acceptable safety profile. This new review was conducted after the approval of meropenem in the US in 2005 for the treatment of patients with complicated skin and skin-structure infections, in addition to the previously approved indications of intra-abdominal infections and paediatric bacterial meningitis. The analysis includes the clinical trial data from the previous safety reviews, updated with expanded experience across a number of serious bacterial infections, including a large international study in patients with skin or skin-structure infections and further experience in patients with intra-abdominal infections and bacterial meningitis. A total of 6154 patients with 6308 meropenem exposures were compared with 4483 patients treated with comparator agents (4593 exposures), and the paediatric population base for which safety data are available has doubled to over 1000 patients. The data presented reinforce the favourable safety profile of meropenem. In general, the incidence and pattern of adverse events occurring with meropenem were similar to those of the first carbapenem, imipenem/cilastatin, and to those of the cephalosporin- and clindamycin-based regimens to which it had been compared. The most common adverse events reported for meropenem were diarrhoea (2.5%), rash (1.4%) and nausea/vomiting (1.2%). No adverse event occurred in more than 3% of patient exposures to meropenem, indicating a low overall frequency of adverse events as well as excellent gastrointestinal tolerability. Furthermore, no unexpected adverse events were identified, and the very low incidence of seizures in patients with meningitis was not considered to be drug related. In infections other than meningitis, the incidence of seizures considered by investigators to be related to meropenem treatment was 0.07%. In the new studies that updated the earlier safety data, no new cases of drug-related seizure were reported for any treatment or patient group (meningitis/non-meningitis infections). In conclusion, meropenem is well tolerated and has good CNS and gastrointestinal tolerability when used for the treatment of serious bacterial infections in a wide range of adult and paediatric patient populations.
- Published
- 2007
34. Messung kleiner Herzvolumina mit Transpulmonaler Thermodilution und 3D-Echokardiographie im Tiermodell
- Author
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D. Ladage, K. Linden, E. Gatzweiler, Georg D. Duerr, O. Dewald, M. Seehase, Ulrike Herberg, and Johannes Breuer
- Subjects
Pulmonary and Respiratory Medicine ,business.industry ,Medicine ,Surgery ,Cardiology and Cardiovascular Medicine ,Nuclear medicine ,business - Published
- 2015
35. Validation of Pressure Volume Relations Derived from 3D Real-Time Echocardiography and Mini Pressure Wire in Piglets
- Author
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M. Seehase, Ulrike Herberg, Johannes Breuer, O. Dewald, E. Gatzweiler, K. Linden, J. Dörner, G.D. Dürr, and D. Ladage
- Subjects
Pulmonary and Respiratory Medicine ,Cardiac function curve ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Diastole ,Hemodynamics ,Esmolol ,Pressure wire ,Cardiac magnetic resonance imaging ,Internal medicine ,Ventricular pressure ,Cardiology ,Medicine ,Pressure volume ,Surgery ,Cardiology and Cardiovascular Medicine ,business ,medicine.drug - Abstract
Background: Pressure-volume relations (PVR) provide vital information regarding ventricular performance and cardiac pathophysiology. However, in children acquisition of PVR by conductance-technology is - due to catheter size and invasiveness - restricted to an older age. Objectives: The aim of the study was to validate the accuracy of minimal invasive assessment of PVR in small hearts using volume data obtained by real-time three-dimensional echocardiography (3D) and simultaneously acquired pressure data. Methods: In 17 piglets (mean weight:5 0.9 ± 1.3 [range 3.6–8.0] kg) left ventricular PVR were generated by 3D in conjunction with simultaneously recording of left ventricular pressure using a mini pressure wire (PVR3D). PVR3D were compared with conductance catheter measurements (PVRCond) under various hemodynamic conditions: baseline, adrenergic stimulation (phenylephrine) and β-adrenoreceptor blockage (esmolol). In another 8 pigles, the accuracy of 3D volumetric data including volume changes over time was validated by cardiac magnetic resonance imaging (CMR) . Results: Computation of PVR3D was feasible, reproducible and comparable to results obtained by conductance technology . Bland-Altman analysis showed a low bias between PVR3D and PVRCond for systolic (systolic myocardial elastance, arterial elastance dp/dtmax) and diastolic parameters (Tau, enddiastolic PVR, dp/dtmin). The dynamic changes under different hemodynamics conditions correlated well between the two methods (Fig. 1). Comparision of CMR and 3DE revealed excellent correlation (r = 0.8829). Inter- and intraobserver- coefficients of variation were below 5% for all parameters . Conclusions: 3D echocardiography generated PVR represent a novel, feasible and reliable method to assess different conditions of cardiac function in small hearts. Due to its minimal invasive character this methodology may be implemented into daily practice and contribute to clinical decision making in this crucial age group.
- Published
- 2015
36. Zygomycosis in Solid Organ Transplant Recipients in a Tertiary Transplant Center and Review of the Literature
- Author
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John J. Fung, Shimon Kusne, Peter K. Linden, Nikolaos G. Almyroudis, Michael G. Rinaldi, and Deanna A. Sutton
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,Gastroenterology ,Organ transplantation ,Hospitals, University ,Postoperative Complications ,Zygomycosis ,Internal medicine ,medicine ,Humans ,Immunology and Allergy ,Pharmacology (medical) ,Disseminated disease ,Survival rate ,Mycosis ,Transplantation ,business.industry ,Incidence ,Mucormycosis ,Immunosuppression ,Organ Transplantation ,Pennsylvania ,medicine.disease ,Surgery ,Survival Rate ,business - Abstract
Zygomycetes are ubiquitous fungi that can cause invasive disease associated with high mortality. We report 10 solid organ transplant recipients with zygomycosis (incidence 2 per 1000) and reviewed 106 cases in the English-language literature. These included renal (n = 73), heart (n = 16), lung (n = 4), heart/lung (n = 2), liver (n = 19) and kidney/pancreas (n = 2) transplant recipients. All patients were receiving immunosuppression and the vast majority steroids. The clinical presentation included rhino-sino-orbital (n = 20), rhinocerebral (n = 16), pulmonary (n = 28), gastrointestinal (n = 13), cutaneous (n = 18), renal (n = 6) and disseminated disease (n = 15). Most frequently isolated genera were Rhizopus (73%) followed by Mucor (13%). The overall mortality was 49%. While rhino-sino-orbital disease had the best prognosis, rhinocerebral disease had high mortality (93%) comparable to disseminated disease. A favorable outcome was associated with limited, surgically accessible disease and early surgical intervention along with amphotericin B administration.
- Published
- 2006
37. Parenteral and Inhaled Colistin for Treatment of Ventilator-Associated Pneumonia
- Author
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Peter K. Linden and David L. Paterson
- Subjects
Microbiology (medical) ,medicine.medical_specialty ,medicine.drug_class ,Antibiotics ,medicine.disease_cause ,Administration, Inhalation ,Pneumonia, Bacterial ,medicine ,Humans ,Infusions, Parenteral ,Pseudomonas Infections ,Dosing ,Intensive care medicine ,Retrospective Studies ,Antibacterial agent ,Cross Infection ,Ventilators, Mechanical ,Acinetobacter ,biology ,Colistin ,business.industry ,Pseudomonas aeruginosa ,Bacterial pneumonia ,Ventilator-associated pneumonia ,biology.organism_classification ,medicine.disease ,Anti-Bacterial Agents ,Acinetobacter baumannii ,Treatment Outcome ,Infectious Diseases ,business ,Acinetobacter Infections ,medicine.drug - Abstract
The spectrum of available therapeutic options has become drastically narrowed in recent years, particularly for nosocomial multidrug-resistant gram-negative pathogens. This therapeutic void has created a resurgence of interest in colistin. In 5 published series since 1999, clinical response rates for pneumonia due to Pseudomonas aeruginosa or Acinetobacter baumannii treated with intravenous colistin have ranged from 25% to 62%, despite high severity of illness at baseline. De novo nephrotoxicity was observed in 8%-36% of patients, despite close attention to both appropriate dosing and duration of treatment. Neurotoxicity, which was commonly described in the old colistin era, has been exceedingly rare in recent experience. Aerosolized therapy as an adjunct to systemic treatment appears promising, but the current published data are much too limited to allow determination of the incremental benefit of the addition of aerosolized treatment to systemic treatment. Colistin is a reasonably safe last-line therapeutic alternative for pneumonia due to multi- or panresistant P. aeruginosa or A. baumannii.
- Published
- 2006
38. Epidemiological Profile of Linezolid‐Resistant Coagulase‐Negative Staphylococci
- Author
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Carla Baxter, Blair Capitano, Jennifer Adams, David L. Paterson, Brian A. Potoski, Anton Y. Peleg, Lloyd Clarke, Peter K. Linden, Kathleen A. Shutt, Dóra Szabó, and A. William Pasculle
- Subjects
Male ,Microbiology (medical) ,medicine.medical_specialty ,Micrococcaceae ,medicine.drug_class ,Antibiotics ,Microbial Sensitivity Tests ,medicine.disease_cause ,Microbiology ,chemistry.chemical_compound ,Anti-Infective Agents ,Risk Factors ,Acetamides ,Drug Resistance, Bacterial ,Epidemiology ,Staphylococcus epidermidis ,medicine ,Humans ,heterocyclic compounds ,Oxazolidinones ,Antibacterial agent ,biology ,business.industry ,Linezolid ,Middle Aged ,Staphylococcal Infections ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,biology.organism_classification ,Electrophoresis, Gel, Pulsed-Field ,Infectious Diseases ,chemistry ,bacteria ,Female ,Coagulase ,business ,Staphylococcus ,Enterococcus faecium - Abstract
Surveillance studies have shown that0.1% of coagulase-negative staphylococci are linezolid resistant; however, at our institution, 4% of such organisms were found to be resistant. We investigated the risk factors for and the epidemiological profile of linezolid-resistant coagulase-negative staphylococci.Susceptibility testing and pulsed-field gel electrophoresis were performed to analyze the genetic relatedness of both linezolid-resistant and linezolid-susceptible isolates. Clinical data were retrieved from medical records, and a case-case-control study was performed to identify unique risk factors for linezolid resistance.Isolates recovered from 25 patients with linezolid-resistant coagulase-negative staphylococci were examined; all but 1 of the isolates were identified as Staphylococcus epidermidis, and all but 1 had a minimum inhibitory concentration of linezolid of256 microg/mL. Pulsed-field gel electrophoresis showed that 21 (84%) of 25 linezolid-resistant isolates exhibited genetic relatedness, whereas linezolid-susceptible isolates were of diverse clones. Unique, independent predictors of linezolid resistance included receipt of linezolid in the 3 months preceding isolation of the coagulase-negative staphylococci (odds ratio, 20.6; 95% confidence interval, 5.8-73.0).Linezolid-resistant coagulase-negative staphylococci have emerged at our institution and are predominately of a single clone. We believe that the most likely scenario to explain this emergence is that person-to-person spread of linezolid-resistant coagulase-negative staphylococci led to establishment of skin colonization with the strain. Subsequent use of linezolid was followed by selection of the linezolid-resistant strain, which then became the dominant skin flora. The potential for a parallel scenario involving clonal dissemination followed by selection of linezolid-resistant methicillin-resistant Staphylococcus aureus is a real possibility.
- Published
- 2006
39. Effect of Granulocyte-Monocyte Colony-Stimulating Factor Therapy on Leukocyte Function and Clearance of Serious Infection in Nonneutropenic Patients
- Author
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Nicole Penkosky, Mark H Cohen-Melamed, Adrienne M. Dorrance, Peter K. Linden, Michael R. Pinsky, and Alan J. Rosenbloom
- Subjects
Adult ,Male ,Pulmonary and Respiratory Medicine ,Colony-Stimulating Factor Therapy ,Critical Care and Intensive Care Medicine ,Risk Assessment ,Severity of Illness Index ,Drug Administration Schedule ,Monocytes ,Proinflammatory cytokine ,Sepsis ,Reference Values ,Leukocytes ,medicine ,Humans ,Single-Blind Method ,Prospective Studies ,Infusions, Intravenous ,Aged ,Probability ,Dose-Response Relationship, Drug ,biology ,Tumor Necrosis Factor-alpha ,business.industry ,Monocyte ,Granulocyte-Macrophage Colony-Stimulating Factor ,Middle Aged ,Flow Cytometry ,medicine.disease ,Survival Analysis ,Up-Regulation ,Granulocyte colony-stimulating factor ,Systemic inflammatory response syndrome ,Treatment Outcome ,medicine.anatomical_structure ,Integrin alpha M ,Immunology ,biology.protein ,Female ,L-selectin ,Cardiology and Cardiovascular Medicine ,business ,Follow-Up Studies - Abstract
Study objective Impaired leukocyte function in patients with serious infections may increase mortality. Granulocyte-monocyte colony-stimulating factor (GM-CSF) broadly activates peripheral monocytes and neutrophils. We performed a clinical trial of GM-CSF in septic, hemodynamically stable patients to see whether GM-CSF treatment improved leukocyte function and mortality. Design Randomized, unblinded, placebo-controlled, prospective study. Setting A 600-bed academic tertiary care center with a 120-bed ICU census with a high proportion of immunocompromised, solid-organ transplant recipients. Patients Forty adult patients with infections meeting the criteria for the systemic inflammatory response syndrome but without hemodynamic instability or shock. Interventions Patients with sepsis and a documented infection were randomized to a 72-h infusion of GM-CSF (125 μg/m 2 ) or placebo. Measurements and main results GM-CSF infusion caused the up-regulation of the β 2 -integrin adhesion molecule CD11b and the appearance of the activated (“sticky” or “avid”) form of the molecule on circulating neutrophils and monocytes. CD11b density and avidity increases in response to the administration of tumor necrosis factor-α were blunted prior to treatment in these patients with serious infection. GM-CSF partially repaired this blunted response on both monocytes and neutrophils. It also caused the down-regulation of the adhesion molecule L-selectin on neutrophils and the up-regulation of human leukocyte antigen on monocytes. These changes were consistent with a broad activation of the circulating leukocyte pool. Although mortality and organ failure scores were similar in both groups, infection resolved significantly more often in patients receiving GM-CSF. Conclusions GM-CSF infusion up-regulated the functional markers of inflammation on circulating neutrophils and monocytes and was associated with both the clinical and microbiological resolution of infection. There was no detectable exacerbation of sepsis-related organ failure or other deleterious side effects with the administration of this proinflammatory agent to patients with serious infections.
- Published
- 2005
40. The Importance of Bactericidal Drugs: Future Directions in Infectious Disease
- Author
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Francis P. Tally, Kenneth V. I. Rolston, Manjari Joshi, George A. Pankey, Robert W. Finberg, Michael West, E. Patchen Dellinger, William A. Craig, Peter K. Linden, Michael J. Rybak, John C. Rotschafer, and Robert C. Moellering
- Subjects
Microbiology (medical) ,Blood Bactericidal Activity ,medicine.medical_specialty ,Bacteria ,business.industry ,medicine.drug_class ,Antibiotics ,medicine.disease ,Antimicrobial ,Communicable Diseases ,Anti-Bacterial Agents ,Animal data ,Infectious Diseases ,Infectious disease (medical specialty) ,Immunology ,medicine ,Animals ,Humans ,Endocarditis ,Intensive care medicine ,business ,Organism ,Antibacterial agent - Abstract
Background. Although a considerable amount of research has gone into the study of the role of bactericidal versus bacteriostatic antimicrobial agents in the treatment of different infectious diseases, there is no accepted standard of practice. Methods. A panel of infectious diseases specialists reviewed the available literature to try to define specific recommendations for clinical practice. Results. In infections of the central nervous system, the rapidity with which the organism is killed may be an important determinant, because of the serious damage that may occur during these clinical situations. The failure of bacteriostatic antibiotics to adequately treat endocarditis is well documented, both in human studies and in animal models. Conclusion. The bulk of the evidence supports the concept that, in treating endocarditis and meningitis, it is important to use antibacterial agents with in vitro bactericidal activity. This conclusion is based on both human and animal data. The data to support bactericidal drugs' superiority to bacteriostatic drugs do not exist for most other clinical situations, and animal models do not support this concept in some situations. Clinicians should be aware that drugs that are bacteriostatic for one organism may in fact be bactericidal for another organism or another strain of the same organism.
- Published
- 2004
41. Use of Parenteral Colistin for the Treatment of Serious Infection Due to Antimicrobial-Resistant Pseudomonas aeruginosa
- Author
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Shimon Kusne, Paulo Fontes, David L. Paterson, Kim C. Coley, David J. Kramer, and Peter K. Linden
- Subjects
Adult ,Male ,Microbiology (medical) ,medicine.medical_specialty ,Salvage therapy ,Microbial Sensitivity Tests ,Drug resistance ,medicine.disease_cause ,Internal medicine ,medicine ,Humans ,Infusions, Parenteral ,Pseudomonas Infections ,Aged ,Salvage Therapy ,Colistin ,business.industry ,Septic shock ,Pseudomonas aeruginosa ,Ventilator-associated pneumonia ,Drug Resistance, Microbial ,Middle Aged ,medicine.disease ,Anti-Bacterial Agents ,Surgery ,Intensive Care Units ,Pneumonia ,Treatment Outcome ,Infectious Diseases ,Bacteremia ,Female ,business ,medicine.drug - Abstract
Serious infection due to strains of Pseudomonas aeruginosa that exhibit resistance to all common antipseudomonal antimicrobials increasingly is a serious problem. Colistin was used as salvage therapy for 23 critically ill patients with multidrug-resistant P. aeruginosa infection. Twenty-two patients who had septic shock (n=14) and/or renal failure (n=21) received mechanical ventilatory support at baseline. The most common types of infection were pneumonia (n=18) and intra-abdominal infection (n=5). Colistin was administered for a median of 17 days (range, 7-36 days). Seven patients died during therapy, at a median of 17 days (range, 4-26 days) after initiation of treatment. A favorable clinical response was observed in 14 patients (61%); only 3 patients experienced relapse. Bacteremia was the only significant factor associated with treatment failure (P=.02). One patient manifested diffuse weakness that resolved after temporary cessation of colistin therapy. Colistin provides an important salvage therapeutic option for patients with otherwise untreatable serious P. aeruginosa infection.
- Published
- 2003
42. Reassessing the value of short-term mortality in sepsis: Comparing conventional approaches to modeling
- Author
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Peter K. Linden, Michael R. Pinsky, Derek C. Angus, Gilles Clermont, Kenneth G. Kalassian, Walter T. Linde-Zwirble, and Nagarajan Ramakrishnan
- Subjects
Male ,medicine.medical_specialty ,Resuscitation ,Time Factors ,Endpoint Determination ,Psychological intervention ,Critical Care and Intensive Care Medicine ,Sepsis ,Risk Factors ,Internal medicine ,Intensive care ,Humans ,Medicine ,Intensive care medicine ,Survival analysis ,APACHE ,Models, Statistical ,business.industry ,Liver Diseases ,Age Factors ,Middle Aged ,medicine.disease ,Survival Analysis ,Clinical trial ,Bacteremia ,Cohort ,Female ,Kidney Diseases ,Gram-Negative Bacterial Infections ,business - Abstract
Objective: Clinical trials of therapies for sepsis have been mostly unsuccessful in impacting mortality. This may be partly due to the use of insensitive mortality end points. We explored whether modeling survival was more sensitive than traditional end points in detecting mortality differences in cohorts of patients with sepsis. Design: Patients were stratified into seven a priori defined paired subgroups that reflected high and low mortality risk according to known clinical risk factors. We fitted an exponential survival model to the high- and low-risk cohort of each subgroup, providing estimates of the rate of dying, long-term survival, and excess day 1 mortality. Mortality in the high- and low-risk cohorts in each subgroup was compared using model parameters, fixed-point mortality, and Kaplan-Meier survival analysis. Setting: Eight intensive care units within a university teaching institution. Patients: One hundred thirty patients with severe sepsis or suspected Gram-negative bacteremia. Interventions: None. Measurements and Main Results: Overall mortality of the cohort was 58.5% at 28 days. The survival of the entire cohort was well described by an exponential model (r2 = .99). Modeling identified differences in high- and low-risk cohorts in five of the seven paired subgroups, while conventional end-points only detected differences in 2. Conclusions: Modeling survival was more sensitive than conventional end-points in identifying survival differences between high- and low-risk subgroups. We encourage further evaluation of modeling in the search for more sensitive mortality end points.
- Published
- 2003
43. Can enterococcal infections initiate sepsis syndrome?
- Author
-
Peter K. Linden
- Subjects
biology ,Septic shock ,Drotrecogin alfa ,Virulence ,Surgical wound ,biology.organism_classification ,medicine.disease ,Microbiology ,Sepsis ,Infectious Diseases ,Antibiotic resistance ,Enterococcus ,medicine ,Pathogen ,medicine.drug - Abstract
Enterococci are the third most common nosocomial bloodstream pathogen and frequently are the causative pathogen(s) of intra-abdominal, genitourinary, surgical wound, endovascular, or other serious infections. In addition to a diverse spectrum of intrinsic and acquired antimicrobial resistance mechanisms, some strains of enterococci exhibit numerous virulence factors that facilitate mucosal adherence, tissue invasiveness, endovascular attachment, and inflammation production. However, the opportunistic nature of enterococcal infection coupled with animal models of experimental enterococcal and mixed infection have caused many to question the independent capacity of this organism to incite severe sepsis or septic shock. Despite evidence suggesting that this organism possesses low intrinsic virulence, observational and interventional trials of enterococcal bacteremia and sepsis strongly support the notion that Enterococcus is capable of promulgating sepsis as a solitary or copathogen with more serious sequelae in the immunocompromised hosts. Monomicrobial enterococcal bacteremia appears to be increasing during the glycopeptide-resistant era, which bolsters the notion that pure enterococcal sepsis is a real entity.
- Published
- 2003
44. Invasive Aspergillosis in Liver Transplant Recipients: Outcome Comparison of Therapy with Amphotericin B Lipid Complex and a Historical Cohort Treated with Conventional Amphotericin B
- Author
-
Kim C. Coley, John J. Fung, Peter K. Linden, Paolo Fontes, and Shimon Kusne
- Subjects
Male ,Microbiology (medical) ,medicine.medical_specialty ,Antifungal Agents ,Chemistry, Pharmaceutical ,Salvage therapy ,Aspergillosis ,Gastroenterology ,Postoperative Complications ,Amphotericin B ,Internal medicine ,medicine ,Humans ,Mycosis ,Retrospective Studies ,Immunosuppression Therapy ,Drug Carriers ,business.industry ,Retrospective cohort study ,Odds ratio ,Middle Aged ,medicine.disease ,Lipids ,Survival Analysis ,Liver Transplantation ,Surgery ,Transplantation ,Treatment Outcome ,Infectious Diseases ,Cohort ,Female ,business ,medicine.drug - Abstract
Invasive aspergillosis (IA) in liver transplant recipients is associated with poor response rates and a very high mortality rate, despite administration of therapy with conventional amphotericin B. We conducted a single-center, retrospective study to compare the outcome of liver transplant recipients with IA who received amphotericin B lipid complex (ABLC) or conventional amphotericin B. IA was present in 12 ABLC-treated patients (definite, 4; probable, 8) and 29 amphotericin B recipients (definite, 11; probable, 18) in the historical cohort. The 60-day mortality rate was lower in the ABLC cohort: 4 (33%) of 12 patients versus 24 (83%) of 29 patients (P=.006). Only 1 of 4 ABLC recipients with definite IA died, compared with all 11 in the amphotericin B group. Sixty-day survival probability curves was significantly lower in the amphotericin B cohort (P=.008). ABLC therapy was the only independent mortality-protective variable (odds ratio, 0.31; 95% confidence interval, 0.07-0.44; P=.02). First-line or early salvage therapy for IA with ABLC was associated with significantly improved survival relative to a comparable historical group treated with amphotericin B.
- Published
- 2003
45. Trends in Risk Profiles for and Mortality Associated with Invasive Aspergillosis among Liver Transplant Recipients
- Author
-
Nina Singh, David L. Paterson, Shimon Kusne, Patricia Muñoz, Shahid Husain, Robin K. Avery, Peter K. Linden, Barbara D. Alexander, Chen M. Yu, Timothy L. Pruett, Richard Jacobs, Jan Tollemar, and Edward A. Dominguez
- Subjects
Adult ,Male ,Microbiology (medical) ,medicine.medical_specialty ,Adolescent ,Opportunistic infection ,medicine.medical_treatment ,Liver transplantation ,Aspergillosis ,Cohort Studies ,Postoperative Complications ,Risk Factors ,Internal medicine ,Humans ,Medicine ,Age of Onset ,Risk factor ,Mycosis ,Aged ,Transplantation ,business.industry ,Mortality rate ,Middle Aged ,medicine.disease ,Liver Transplantation ,Surgery ,Infectious Diseases ,Cohort ,Female ,business - Abstract
To discern whether the characteristics and outcome of invasive aspergillosis in liver transplant recipients have evolved during the past decade, 26 patients who underwent transplantation during 1990-1995 (known as "the earlier cohort") were compared with 20 patients who underwent transplantation during 1998-2001 (known as "the later cohort"). Twenty-three percent of the Aspergillus infections in the earlier cohort occurredor =90 days after transplantation, compared with 55% of such infections in the later cohort (P=.026). The earlier cohort was significantly more likely to have disseminated infection (P=.034) and central nervous system (CNS) involvement (P=.0004) than was the later cohort. The mortality rate was significantly higher for the earlier cohort (92%) than for the later cohort (60%; P=.012). Only disseminated infection (not the year of transplantation) approached statistical significance as an independent predictor of outcome. In the current era, invasive aspergillosis occurs later in the posttransplantation period, is less likely to be associated with CNS infection, and is associated with a lower mortality rate, compared with invasive aspergillosis in the early 1990s.
- Published
- 2003
46. Recursive Partioning Analysis to Predict Survival for Patients Receiving Cranial Re-irradiation for Brain Metastases
- Author
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Kristopher Dennis, N. Logie, Helen A. Shih, Alysa Fairchild, Y. Xu, Shilo Lefresne, Sunita Ghosh, D. Ciafone, K. Linden, Edward Chow, Natalie Pulenzas, Christina H. Son, Erin Wong, William W. Wong, and Rachel B. Jimenez
- Subjects
Re-Irradiation ,Cancer Research ,medicine.medical_specialty ,Radiation ,Oncology ,business.industry ,Medicine ,Radiology, Nuclear Medicine and imaging ,Radiology ,business - Published
- 2015
47. Association between the Presence of Enterococcal Virulence Factors Gelatinase, Hemolysin, and Enterococcal Surface Protein and Mortality among Patients with Bacteremia Due toEnterococcus faecalis
- Author
-
Robert R. Muder, David R. Snydman, Joseph W. Chow, Peter K. Linden, Nathan Shankar, Marilyn M. Wagener, Mary K. Hayden, Marcus J. Zervos, and Emanuel N. Vergis
- Subjects
Adult ,Male ,Microbiology (medical) ,Adolescent ,Drug Resistance ,Virulence ,Bacteremia ,Microbial Sensitivity Tests ,Drug resistance ,Enterococcus faecalis ,Microbiology ,Hemolysin Proteins ,fluids and secretions ,Bacterial Proteins ,medicine ,Humans ,Gelatinase ,Mortality ,Aged ,Aged, 80 and over ,biology ,Hemolysin ,Middle Aged ,biochemical phenomena, metabolism, and nutrition ,medicine.disease ,biology.organism_classification ,Streptococcaceae ,Anti-Bacterial Agents ,Infectious Diseases ,Enterococcus ,Gelatinases ,Female - Abstract
The potential virulence factors of enterococci include production of enterococcal surface protein (Esp), gelatinase, and hemolysin. Gelatinase- and hemolysin-producing strains of Enterococcus faecalis have been shown to be virulent in animal models of enterococcal infections. Esp production has been shown to enhance the persistence of E. faecalis in the urinary bladder. We determined the presence of the esp gene and production of gelatinase and hemolysin in 219 E. faecalis isolates from a larger prospective study of 398 patients with enterococcal bacteremia. Thirty-two percent of isolates carried the esp gene, 64% produced gelatinase, and 11% produced hemolysin. There was no significant association between 14-day mortality and any of the markers studied, singly or in combination.
- Published
- 2002
48. Transient splenial lesion in influenza A H1N1 2009 infection
- Author
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H. Tschampa, Lentze Ml, T. Rosenbaum, B. Köster, A.-M. Eis-Hübinger, K. Linden, Arne Simon, M. Born, Olga Moser, and Gudrun Fleischhack
- Subjects
Pathology ,medicine.medical_specialty ,business.industry ,viruses ,Encephalopathy ,Medizin ,virus diseases ,Splenium ,Context (language use) ,Fluid-attenuated inversion recovery ,Corpus callosum ,medicine.disease ,Lesion ,medicine ,Radiology, Nuclear Medicine and imaging ,medicine.symptom ,Splenial ,business ,Encephalitis - Abstract
Severe neurologic complications have been rarely reported during novel pandemic influenza A(H1N1) virus infections. We describe the case of an 10-year-old boy with new onset seizures and proven influenza A(H1N1) 2009 infection showing a reversible hyperintense lesion in the splenium of the corpus callosum on T2-weighted and FLAIR magnetic resonance images without contrast enhancement. Transient splenial lesions have been described in the context of virus encephalopathy and do not require specific treatment.
- Published
- 2011
49. Nutritional support of critically ill immuno-compromised patients
- Author
-
Peter K. Linden
- Subjects
Malnutrition ,medicine.medical_specialty ,Parenteral nutrition ,business.industry ,Critically ill ,Intensive care ,Medicine ,Clinical nutrition ,Pain management ,business ,medicine.disease ,Intensive care medicine ,Nutritional deficiency - Published
- 2014
50. Hyperbilirubinemia during Quinupristin-Dalfopristin Therapy in Liver Transplant Recipients: Correlation with Available Liver Biopsy Results
- Author
-
Peter K. Linden, François Bompart, George H. Talbot, and Sharon L. Gray
- Subjects
Adult ,Male ,medicine.medical_specialty ,Biopsy ,medicine.medical_treatment ,Dalfopristin ,Virginiamycin ,Gastroenterology ,Cholestasis ,Internal medicine ,Enterococcus faecalis ,polycyclic compounds ,medicine ,Humans ,Pharmacology (medical) ,Gram-Positive Bacterial Infections ,Aged ,Hyperbilirubinemia ,Retrospective Studies ,Antibacterial agent ,medicine.diagnostic_test ,business.industry ,Quinupristin ,Bilirubin ,Middle Aged ,biochemical phenomena, metabolism, and nutrition ,medicine.disease ,Liver Transplantation ,Surgery ,Transplantation ,Liver ,Liver biopsy ,Female ,Histopathology ,business - Abstract
Study Objective. To review the liver histopathology in transplant recipients who developed hyperbilirubinemia during therapy with quinupristin-dalfopristin, a new streptogramin antibiotic, and to ascertain whether objective histologic evidence of adverse drug effect could be correlated to serum bilirubin levels. Design. Retrospective analysis. Setting. University of Pittsburgh Medical Center. Patients. From a database of 34 liver recipients who received quinupristin-dalfopristin for vancomycin-resistant Enterococcus faecium infection who were prospectively enrolled in a multicenter, open-label, emergency-use protocol, the data for a subset of 25 patients who underwent one or more liver biopsies during therapy were reviewed for this study. Interventions. Quinupristin-dalfopristin was administered intravenously at 7.5 mg/kg every 8 hours. Available serum bilirubin levels from before, during, and 1 week after therapy were tabulated. Liver biopsy results obtained within 1 week before and during therapy were retrospectively reviewed. Histopathologic results were characterized and correlated to bilirubin level. Measurements and Main Results. Cholestatic changes were already present in 15 of 17 patients who underwent biopsy before therapy. During therapy, the most common findings from 40 biopsies (25 patients) were cholestasis (33 biopsies), acute rejection (10), and periportal inflammation (8). There was no evidence of drug-specific histopathologic injury. Conclusion. Hyperbilirubinemia in these patients was likely multifactorial and most frequently due to sepsis and prior graft injury.
- Published
- 2001
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