128 results on '"Carlson, D."'
Search Results
2. New materials for improving catches of horseflies (Diptera: Tabanidae) in Nzi traps.
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Mihok, S. and Carlson, D. A.
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HORSEFLIES , *SYNTHETIC textiles , *DIPTERA , *MOSQUITO nets , *ULTRAVIOLET radiation - Abstract
New materials in 85 configurations were tested relative to standard fabric Nzi traps to improve catches of tabanids based on artificial visual cues that mimic those used in nature for locating hosts or water. Colour‐fast synthetic fabrics and photo‐selective horticultural mesh were tested to facilitate insecticide impregnation and for improved durability. Many plastics were explored to document how flies react to polarized and visible vs. ultraviolet light. Lastly, sticky horizontal, linearly polarizing ground‐level shiny plastic targets were tested for capturing water‐seeking tabanids relative to traps and vertical fabric targets. Based on the capture of 281 786 female Tabanidae (Tabanus Linnaeus, Hybomitra Enderlein, Chrysops Meigen), four alternative formats provided higher catches and/or durability. They were substituting: (1) phthalogen turquoise for phthalogen blue, (2) solution‐dyed fabrics for blue and black cotton, (3) clear/white horticultural mesh for mosquito netting, and (4) clear, reflective plastic for some or all netting. A Sunbrella/BioNet fabric trap (portable) and a blue‐black Plexiglas®/netting trap (fixed applications) consistently performed best (1.5–3 × higher catches). Ground‐level targets captured many male and gravid female Hybomitra but were ineffective for Tabanus. Traps and vertical fabric or transparent sticky targets captured mainly unfed females. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
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3. Procedural sedation: providing the missing definition.
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Green, S. M., Irwin, M. G., Mason, K. P., Absalom, A, Alcaino, E, Andolfatto, G, Babl, F, Barbi, E, Carlson, D, Rezende Costa, L, Costa, P. S. S., Leroy, P, Roback, M. G., Roelofse, J, Yuen, V, and International Committee for the Advancement of Procedural Sedation
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DEFINITIONS ,POSITIVE pressure ventilation - Abstract
Keywords: procedural sedation; definition; consensus EN procedural sedation definition consensus 598 601 4 04/05/21 20210501 NES 210501 Surprisingly, there is no generally accepted definition for the practice of procedural sedation. Sedation states within the purview of the above definition include minimal sedation, moderate sedation, dissociative sedation and deep sedation. Similarly, whereas awareness/recall should not occur during general anaesthesia, for procedural sedation it is, by definition, very likely with minimal or moderate sedation and possible with deep sedation. [Extracted from the article]
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- 2021
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4. An international multidisciplinary consensus statement on fasting before procedural sedation in adults and children.
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Green, S. M., Leroy, P. L., Roback, M. G., Irwin, M. G., Andolfatto, G., Babl, F. E., Barbi, E., Costa, L. R., Absalom, A., Carlson, D. W., Krauss, B. S., Roelofse, J., Yuen, V. M., Alcaino, E., Costa, P. S., Mason, K. P., and International Committee for the Advancement of Procedural Sedation
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FASTING ,RESEARCH ,CONSCIOUS sedation ,RESEARCH methodology ,EVALUATION research ,MEDICAL cooperation ,MEDICAL protocols ,COMPARATIVE studies ,RESEARCH funding ,DELPHI method ,ALGORITHMS - Abstract
The multidisciplinary International Committee for the Advancement of Procedural Sedation presents the first fasting and aspiration prevention recommendations specific to procedural sedation, based on an extensive review of the literature. These were developed using Delphi methodology and assessment of the robustness of the available evidence. The literature evidence is clear that fasting, as currently practiced, often substantially exceeds recommended time thresholds and has known adverse consequences, for example, irritability, dehydration and hypoglycaemia. Fasting does not guarantee an empty stomach, and there is no observed association between aspiration and compliance with common fasting guidelines. The probability of clinically important aspiration during procedural sedation is negligible. In the post-1984 literature there are no published reports of aspiration-associated mortality in children, no reports of death in healthy adults (ASA physical status 1 or 2) and just nine reported deaths in adults of ASA physical status 3 or above. Current concerns about aspiration are out of proportion to the actual risk. Given the lower observed frequency of aspiration and mortality than during general anaesthesia, and the theoretical basis for assuming a lesser risk, fasting strategies in procedural sedation can reasonably be less restrictive. We present a consensus-derived algorithm in which each patient is first risk-stratified during their pre-sedation assessment, using evidence-based factors relating to patient characteristics, comorbidities, the nature of the procedure and the nature of the anticipated sedation technique. Graded fasting precautions for liquids and solids are then recommended for elective procedures based upon this categorisation of negligible, mild or moderate aspiration risk. This consensus statement can serve as a resource to practitioners and policymakers who perform and oversee procedural sedation in patients of all ages, worldwide. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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5. An Updated View on Water Masses on the pan‐West Greenland Continental Shelf and Their Link to Proglacial Fjords.
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Rysgaard, S., Boone, W., Carlson, D., Sejr, M. K., Bendtsen, J., Juul‐Pedersen, T., Lund, H., Meire, L., and Mortensen, J.
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TERRITORIAL waters ,HYDROGRAPHY ,WATER masses ,SALINITY - Abstract
The accelerated melt of the Greenland Ice Sheet has been linked to a sudden increase in the presence of warm subsurface coastal water in west Greenland. Yet pathways of warm coastal water along the entire west Greenland coast have remained largely unstudied. Here we present the first, near‐synoptic hydrographic observations at both the continental slope and fjord entrances of the west Greenland coastal system from Cape Farewell (59°N) to Melville Bay (75°N) in summer 2016. We observed a distinct north‐south division in the water mass distribution in west Greenland, approximately partitioned by the northern part of Davis Strait, and a division between the continental slope and fjord entrances. Waters from the regional southern freshwater source with origin in the East Greenland Current that rounds Cape Farewell are not observed to enter Baffin Bay. The regional heat source transported by the west Greenland Current is blocked by Southwest Greenland Coastal Water in the south but the deep connections in the north allow warm deep Subpolar Mode Water to enter fjords. Furthermore, we observed cold and relative saline Baffin Bay Polar Water over the inner part of the banks, periodically reaching as far south as 64°N, suggesting the presence of an undescribed southward current at the Southwest Greenland continental shelf. Key Points: The regional southern freshwater source transported northward along the Greenland west coast did not enter Baffin Bay during summer 2016North of Davis Strait, warm deep Subpolar Mode Water may enter the deep silled fjords unobstructedBaffin Bay Polar Water is observed on the Southwest Greenland coast as far south as 64°N suggesting a seasonal southward coastal current [ABSTRACT FROM AUTHOR]
- Published
- 2020
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6. Inter‐rater agreement of novel high‐resolution impedance manometry metrics: Bolus flow time and esophageal impedance integral ratio.
- Author
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Carlson, D. A., Lin, Z., Kou, W., and Pandolfino, J. E.
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IMPEDANCE spectroscopy , *MANOMETERS , *MEDIAN (Mathematics) , *CONFIDENCE intervals , *STATISTICAL correlation ,ESOPHAGEAL atresia - Abstract
Abstract: Background: Novel high‐resolution impedance manometry (HRIM) metrics of bolus flow time (BFT) and esophageal impedance integral (EII) ratio have demonstrated clinical utility, though the reliability of their analysis has not been assessed. We aimed to evaluate the inter‐rater agreement of the BFT and EII ratio. Methods: HRIM studies including five upright, liquid swallows from 40 adult patients were analyzed by two raters using a customized MATLAB program to generate the BFT and EII ratio. Inter‐rater agreement was assessed using the intraclass correlation coefficient (ICC) for median values generated per patient and also for all 200 swallows. Key Results: The ICC (95% confidence interval, CI) for BFT was 0.873 (0.759‐0.933) for median values and 0.838 (0.778‐0.881) for all swallows. The ICC (95% CI) for EII ratio was 0.983 (0.968‐0.991) for median values and 0.905 (0.875‐0.928) for all swallows. Median values for both BFT and EII ratio were similar between the two raters (P‐values .05). Conclusions and Inferences: The BFT and EII ratio can be reliably calculated as supported by generally excellent inter‐rater agreement. Thus, broader utilization of these measures appears feasible and would facilitate further evaluation of their clinical utility. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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7. Evaluating the reliability and construct validity of the Eckardt symptom score as a measure of achalasia severity.
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Taft, T. H., Carlson, D. A., Triggs, J., Craft, J., Starkey, K., Yadlapati, R., Gregory, D., and Pandolfino, J. E.
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ESOPHAGEAL achalasia , *DEGLUTITION disorders , *WEIGHT loss , *THERAPEUTICS ,ESOPHAGEAL atresia - Abstract
Abstract: Background: Achalasia is a disease of mechanical esophageal dysfunction characterized by dysphagia, chest pain, regurgitation, and malnutrition. The Eckardt symptom score (ESS) is the gold standard self‐report assessment tool. Current guidelines outline a three‐step approach to patient reported outcomes measure design. Developed prior to these policies, the ESS has not undergone rigorous testing of its reliability and validity. Methods: Adult achalasia patients retrospectively identified via a patient registry were grouped based on treatment history. Patients were grouped PREPOST (completed ESS, GERDQ, brief esophageal dysphagia questionnaire, NIH PROMIS Global Health, high resolution manometry, timed barium esophagram prior to treatment and after) and POST (completed measures only after treatment). Clinical characteristics, treatment type and date were obtained via medical record. Standardized psychometric analyses for reliability and construct validity were performed. Key Results: 107 patients identified; 83 POST and 24 PREPOST. The ESS has fair internal consistency and split‐half reliability with a single factor structure. Dysphagia accounts for half the variance in ESS, while chest pain and weight loss account for 10% each. Pre‐post‐surgical assessment demonstrates improvements in ESS, except for weight loss. Effect sizes range from 0.24 to 2.53, with greatest change in regurgitation. Validity of the ESS is supported by modest correlations with GERDQ, HRQOL, and physiological data. Conclusions & Inferences: The ESS demonstrates fair reliability and validity, with a single factor structure mostly explained by dysphagia. Based on psychometric findings, weight loss and chest pain items may be decreasing ESS reliability and validity. Further assessment of the ESS under FDA guidelines is warranted. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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8. Jackhammer esophagus: Assessing the balance between prepeak and postpeak contractile integral.
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Xiao, Y., Carlson, D. A., Lin, Z., Alhalel, N., and Pandolfino, J. E.
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ESOPHAGEAL motility disorders , *ESOPHAGUS diseases , *PERISTALSIS , *DEGLUTITION disorders , *CHEST pain , *PATIENTS - Abstract
Abstract: Background: We hypothesized that symptoms in Jackhammer esophagus (JH) are associated with an imbalance between the prepeak and postpeak phases of contraction. Thus, we developed a method to distinguish the contractile integral components of prepeak and postpeak phase contractile activity to determine the contribution of each phase and their association with dysphagia. Methods: Patients diagnosed with JH were enrolled and compared to controls. The first five intact swallows during manometry were analyzed. A single swallow was divided into a prepeak and postpeak phase. The contractile integral of each phase and its corresponding time‐controlled integral were computed. All metrics were compared between controls and JH patients subcategorized by the impaction dysphagia question (IDQ) score with cut‐off of 6. Key Results: Thirty eight JH patients and 71 controls were included. Twelve JH patients had IDQ ≤ 6 and 26 with IDQ > 6. JH patients had higher contractile integral in both phases, and a higher ratio between postpeak to prepeak contractile integral independent of duration. Similarly, JH patients with an IDQ > 6 had higher contractile metrics than those with IDQ ≤ 6. There was a correlation between the IDQ score and the ratio within the postpeak to prepeak contractile integral (
r = .375). Conclusions: Abnormalities in contractile integral of the postpeak phase are more significant in JH with higher dysphagia scores Although the total postpeak contractile integral was higher in symptomatic patients, this was associated with longer duration of postpeak activity suggesting that dysphagia patients with JH have a defect in the postpeak phase of peristalsis. [ABSTRACT FROM AUTHOR]- Published
- 2018
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9. Validation of the oesophageal hypervigilance and anxiety scale for chronic oesophageal disease.
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Taft, T. H., Triggs, J. R., Carlson, D. A., Guadagnoli, L., Tomasino, K. N., Keefer, L., and Pandolfino, J. E.
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GASTROESOPHAGEAL reflux ,ANXIETY ,QUALITY of life ,PRINCIPAL components analysis ,ESOPHAGEAL motility - Abstract
Summary: Background: Oesophageal hypervigilance and anxiety can drive symptom experience in chronic oesophageal conditions, including gastro‐oesophageal reflux disease, achalasia and functional oesophageal disorders. To date, no validated self‐report measure exists to evaluate oesophageal hypervigilance and anxiety. Aims: This study aims to develop a brief and reliable questionnaire assessing these constructs, the oesophageal hypervigilance and anxiety scale (EHAS). Methods: Questions for the EHAS were drawn from 4 existing validated measures that assessed hypervigilance and anxiety adapted for the oesophagus. Patients who previously underwent high‐resolution manometry testing at a university‐based oesophageal motility clinic were retrospectively identified. Patients were included in the analysis if they completed the EHAS as well as questionnaires assessing symptom severity and health‐related quality of life at the time of the high‐resolution manometry. Results: Nine hundred and eighty‐two patients aged 18‐85 completed the study. The EHAS demonstrates excellent internal consistency (α = 0.93) and split‐half reliability (Guttman = 0.87). Inter‐item correlations indicated multicollinearity was not achieved; thus, no items were removed from the original 15‐item scale. Principal components factor analysis revealed two subscales measuring symptom‐specific anxiety and symptom‐specific hypervigilance. Construct validity for total and subscale scores was supported by positive correlations with symptom severity and negative correlations with health‐related quality of life. Conclusions: The EHAS is a 15‐item scale assessing oesophageal hypervigilance and symptom‐specfic anxiety. The EHAS could be useful in evaluating the role of these constructs in several oesophageal conditions in which hypersensitivity, hypervigilance and anxiety may contribute to symptoms and impact treatment outcomes. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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10. A triple-blind, placebo-controlled randomised trial of the ilioinguinal-transversus abdominis plane (I-TAP) nerve block for elective caesarean section.
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Staker, J. J., Liu, D., Church, R., Carlson, D. J., Panahkhahi, M., Lim, A., and LeCong, T.
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NERVE block ,CESAREAN section ,RANDOMIZED controlled trials ,ANALGESIA ,SPINAL anesthesia ,PLACEBOS ,THERAPEUTIC use of narcotics ,ABDOMINAL muscles ,ANALGESICS ,ANESTHESIA in obstetrics ,COMPARATIVE studies ,FENTANYL ,LOCAL anesthetics ,LONGITUDINAL method ,RESEARCH methodology ,MEDICAL cooperation ,NARCOTICS ,PATIENT satisfaction ,PATIENT-controlled analgesia ,RESEARCH ,EVALUATION research ,PAIN measurement ,BUPIVACAINE ,THERAPEUTICS - Abstract
This study investigated the efficacy of a new ilioinguinal-transversus abdominis plane block when used as a component of multimodal analgesia. We conducted a prospective, triple-blind, placebo-controlled randomised study of 100 women undergoing elective caesarean section. All women had spinal anaesthesia with hyperbaric bupivacaine, 15 μg fentanyl and 150 μg morphine, as well as 100 mg diclofenac and 1.5 g paracetamol rectally. Women were randomly allocated to receive the ilioinguinal-transversus abdominis plane block or a sham block at the end of surgery. The primary outcome was the difference in fentanyl patient-controlled analgesia dose at 24 h. Secondary outcomes included postoperative pain scores, adverse effects and maternal satisfaction. The cumulative mean (95%CI) fentanyl dose at 24 h was 71.9 (55.6-92.7) μg in the ilioinguinal-transversus abdominis group compared with 179.1 (138.5-231.4) μg in the control group (p < 0.001). Visual analogue scale pain scores averaged across time-points were 1.9 (1.5-2.3) mm vs. 5.0 (4.3-5.9) mm (p = 0.006) at rest, and 4.7 (4.1-5.5) mm vs. 11.3 (9.9-13.0) mm (p = 0.001) on movement, respectively. Post-hoc analysis showed that the ilioinguinal-transversus abdominis group was less likely to use ≥ 1000 μg fentanyl compared with the control group (2% vs. 16%; p = 0.016). There were no differences in opioid-related side-effects or maternal satisfaction with analgesia. The addition of the ilioinguinal-transversus abdominis plane block provides superior analgesia to our usual multimodal analgesic regimen. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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11. Esophageal provocation tests: Are they useful to improve diagnostic yield of high resolution manometry?
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Carlson, D. A. and Roman, S.
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ESOPHAGEAL motility disorders , *PROVOCATION tests (Medicine) , *MANOMETERS , *GASTROESOPHAGEAL reflux , *FUNDOPLICATION , *DIAGNOSIS - Abstract
Abstract: High resolution manometry (HRM) is the gold standard to diagnose esophageal motility disorders but has some limitations. The inclusion of provocative tests might enhance the diagnostic yield of HRM. These tests are easy to perform and to add to the regular manometry protocol. Multiple rapid swallows (MRS; 5 2‐mL swallows) is useful to assess the contractile reserve and deglutitive inhibition. The optimal number of MRS to perform might be 3 as suggested by Mauro et al. in this issue of
Neurogastroenterology & Motility . The absence of contractile reserve might be associated with gastro‐esophageal reflux disease and with an increased risk of post fundoplication dysphagia. Single viscous and solid swallows might enhance the detection of esophageal motility disorders but are not significantly associated with symptom occurrence. Test meal has the advantage to represent a real‐life scenario and is promising to depict significant motility findings responsible for esophageal symptoms. Post‐prandial recording might also be of interest to diagnose rumination and belching disorders. The best indication of rapid drink challenge test (free drinking of 200 mL) is currently the diagnosis of esophago‐gastric junction obstruction. Finally, abdominal compression might be an option to evaluate response of esophageal peristalsis in a context of outflow resistance as proposed by Brink et al. in this issue. These provocative maneuvers appear to provide a complementary role in the evaluation of esophageal motility but require prospective studies to determine the validity of the findings and whether they will lead to changes in clinical practice. [ABSTRACT FROM AUTHOR]- Published
- 2018
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12. The relationship between esophageal acid exposure and the esophageal response to volumetric distention.
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Carlson, D. A., Craft, J., Tye, M., Lin, Z., Kahrilas, P. J., Pandolfino, J. E., and Kathpalia, P.
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ESOPHAGOGASTRIC junction diseases , *GASTROESOPHAGEAL reflux in children , *PERISTALSIS , *AEROPHAGY , *ESOPHAGEAL motility disorders - Abstract
Abstract: Background: Increased esophagogastric junction (EGJ) distensibility is thought to contribute to gastroesophageal reflux disease (GERD). Using the functional lumen imaging probe (FLIP), we aimed to assess the esophageal response to distension among patients undergoing esophageal pH monitoring. Methods: 25 patients (ages 22‐73; 13 females) who underwent ambulatory wireless esophageal pH testing while off proton‐pump inhibitors were evaluated with FLIP during sedated upper endoscopy. Esophageal reflux was quantified by total percent acid exposure time (AET; <6% was considered normal). FLIP studies were analyzed using a customized program generate FLIP topography plots to identify esophageal contractility patterns and to calculate the EGJ‐distensibility index (DI). Reflux symptoms were assessed with the GERDQ. Values reflect median (interquartile range). Results: Among all patients, the AET was 7.2% (3.7‐11.1) and EGJ‐DI was 4.2 (2.5‐7.6) mm2/mm Hg. Repetitive antegrade contractions (RACs) were induced in 19/25 (76%) of patients; AET was lower among patients with (6.1%, 3‐7.8) than without (14.9, 8.5‐22.3) RACs (
P = .009). Correlation was weak and insignificant between AET and EGJ‐DI, GERDQ and AET, and GERDQ and EGJ‐DI. Patients with abnormal AET (n = 16) and normal AET (n = 9) had similar EGJ‐DI, 4.6 mm2/mm Hg (2.9‐9.2) vs 3.2 (2.2‐5.1),P = .207 and GERDQ,P = .138. Conclusions: Abnormal esophageal acid exposure was associated with an impaired contractile response to volume distention of the esophagus. This supports that acid exposure is dependent on acid clearance mechanisms. [ABSTRACT FROM AUTHOR]- Published
- 2018
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13. Abnormal esophageal acid exposure on high‐dose proton pump inhibitor therapy is common in systemic sclerosis patients.
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Stern, E. K., Carlson, D. A., Falmagne, S., Hoffmann, A. D., Carns, M., Pandolfino, J. E., Hinchcliff, M., and Brenner, D. M.
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ESOPHAGEAL motility disorders , *SYSTEMIC scleroderma , *PROTON pump inhibitors , *ENDOSCOPY , *BOLUS (Digestion) , *PATIENTS , *THERAPEUTICS - Abstract
Abstract: Background: Esophageal dysfunction and gastro‐esophageal reflux disease (GERD) are common among patients with systemic sclerosis (SSc). Although high‐dose proton pump inhibitors (PPIs) typically normalize esophageal acid exposure, the effectiveness of PPI therapy has not been systematically studied in SSc patients. The aim of this study was to characterize reflux in SSc patients on high‐dose PPI using esophageal pH‐impedance testing. Methods: In this case‐controlled retrospective analysis, 38 patients fulfilling 2013 American College of Rheumatology SSc criteria who underwent esophageal pH‐impedance testing on twice‐daily PPI between January 2014 and March 2017 at a tertiary referral center were compared with a control‐cohort of 38 non‐SSc patients matched for PPI formulation and dose, hiatal hernia size, age, and gender. Patient clinical characteristics, including endoscopy and high‐resolution manometry findings, were assessed via chart review. Key Results: On pH‐impedance, SSc patients had higher acid exposure times (AETs) than controls. Sixty‐one percent of the SSc patients and 18% of the control patients had a total AET ≥4.5% (
P < .001). Systemic sclerosis patients also had significantly longer AETs, longer median bolus clearance, and lower nocturnal impedance values. Conclusions & Inferences: Abnormal esophageal acid exposure despite high‐dose PPI therapy was common among patients with SSc. The lack of increased reflux episodes in the SSc patients, and longer bolus clearance times and lower nocturnal impedance, supports ineffective clearance as the potential mechanism. Systemic sclerosis patients may require adjunctive therapies to PPIs to control acid reflux. [ABSTRACT FROM AUTHOR]- Published
- 2018
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14. High-resolution manometry assessment of the lower esophageal sphincter after-contraction: Normative values and clinical correlation.
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Carlson, D. A., Kahrilas, P. J., Tye, M., Listernick, Z., Ritter, K., Wong, I., Xiao, Y., Bul, V., and Pandolfino, J. E.
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ESOPHAGOGASTRIC junction , *ESOPHAGEAL motility , *DEGLUTITION disorders , *PERISTALSIS , *LIKERT scale , *DIAGNOSIS - Abstract
Background The Chicago Classification v3.0 proposed extending the distal contractile integral ( DCI) measurement domain to include the lower esophageal sphincter ( LES) to enhance the detection of esophageal hypercontractility. However, normative and clinical data for this approach are unreported. We aimed to describe the application of an extended DCI measurement in asymptomatic controls and patients. Methods High-resolution manometry ( HRM) of 65 asymptomatic controls and 72 patients with normal motility were evaluated retrospectively. Dysphagia and chest pain symptoms were assessed using the brief esophageal dysphagia questionnaire ( BEDQ); ≥10 was considered abnormal. HRM studies of 10 supine swallows were evaluated via the standard DCI and an extended DCI measurement domain ( DCI+) to include the lower esophageal sphincter ( LES) during and after the peristaltic wave. The DCI-increment was calculated as the DCI+ minus DCI. Key Results Among controls, the median (5-95th percentile) DCI+ was 1915 (1359-6921) mm Hg/cm/s and DCI-increment was 534 (126-1488) mm Hg/cm/s. Two patients (3%) had ≥2 swallows with DCI+ >8000 mm Hg/cm/s and seven (10%) patients had at least one swallow with DCI+ >8000 mm Hg/cm/s, ie, had potential motility reclassification by application of DCI+. Seven of these nine patients (78%) were evaluated for dysphagia or chest pain, but only 3/9 (33%) had an abnormal BEDQ. Conclusions and Inferences Extension of the DCI measurement domain may aid quantifying hypercontractility that involves the LES. However, adjusting management strategies based on reclassification of patients with otherwise normal motility should be cautiously considered. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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15. Assessing the pre- and postpeak phases in a swallow using esophageal pressure topography.
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Xiao, Y., Carlson, D. A., Lin, Z., Rinella, N., Sifrim, D., and Pandolfino, J. E.
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ESOPHAGEAL physiology , *ESOPHAGEAL motility , *MANOMETERS , *DEGLUTITION - Abstract
Background The current paradigm of measuring esophageal contractile vigor assesses the entirety of a pressure wave using a single measurement, the distal contractile integral (DCI). We hypothesize that an assessment identifying separate phases of the contractile pressure wave before and after the pressure peak may help distinguish abnormalities in patients presenting with chest pain and dysphagia. The aim of the present study was to develop a technique to assess the individual phases and report on the values in healthy controls. Methods Seventy-one healthy controls were enrolled. High-resolution manometry studies of five intact liquid swallows in both supine and upright positions were analyzed using a customized MATLAB program to divide swallows into a prepeak phase and postpeak phase, and compute the contractile integral of both phases. The contractile integrals were also controlled by duration over each phase. Key Results The composite DCI measurement in healthy controls appears to be weighted toward slightly higher contractile activity during postpeak phase based on postpeak to prepeak ratios in both the supine and upright position (1.50 and 1.49, respectively). The contribution of postpeak phase on the composite DCI was weakened when controlled by time (0.92 and 0.96 in both supine and upright position, respectively). Conclusions and Inferences We developed a novel measurement focused on separating the prepeak and postpeak components of the peristaltic contractile activity during swallowing. Using this technique, it appears that overall contractile activity is higher during postpeak phase and this is related to the longer time component during this phase. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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16. High-resolution impedance manometry parameters enhance the esophageal motility evaluation in non-obstructive dysphagia patients without a major Chicago Classification motility disorder.
- Author
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Carlson, D. A., Omari, T., Lin, Z., Rommel, N., Starkey, K., Kahrilas, P. J., Tack, J., and Pandolfino, J. E.
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DEGLUTITION disorders , *PATIENTS , *GASTROESOPHAGEAL reflux , *QUESTIONNAIRES , *EVALUATION - Abstract
Background High-resolution impedance manometry ( HRIM) allows evaluation of esophageal bolus retention, flow, and pressurization. We aimed to perform a collaborative analysis of HRIM metrics to evaluate patients with non-obstructive dysphagia. Methods Fourteen asymptomatic controls (58% female; ages 20-50) and 41 patients (63% female; ages 24-82), 18 evaluated for dysphagia and 23 for reflux (non-dysphagia patients), with esophageal motility diagnoses of normal motility or ineffective esophageal motility, were evaluated with HRIM and a global dysphagia symptom score (Brief Esophageal Dysphagia Questionnaire). HRIM was analyzed to assess Chicago Classification metrics, automated pressure-flow metrics, the esophageal impedance integral ( EII) ratio, and the bolus flow time ( BFT). Key Results Significant symptom-metric correlations were detected only with basal EGJ pressure, EII ratio, and BFT. The EII ratio, BFT, and impedance ratio differed between controls and dysphagia patients, while the EII ratio in the upright position was the only measure that differentiated dysphagia from non-dysphagia patients. Conclusions & Inferences The EII ratio and BFT appear to offer an improved diagnostic evaluation in patients with non-obstructive dysphagia without a major esophageal motility disorder. Bolus retention as measured with the EII ratio appears to carry the strongest association with dysphagia, and thus may aid in the characterization of symptomatic patients with otherwise normal manometry. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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17. Evaluation of esophageal distensibility in eosinophilic esophagitis: an update and comparison of functional lumen imaging probe analytic methods.
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Carlson, D. A., Lin, Z., Hirano, I., Gonsalves, N., Zalewski, A., and Pandolfino, J. E.
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DIAGNOSIS of esophageal cancer , *ESOPHAGEAL tumors , *EOSINOPHILIC esophagitis , *EOSINOPHIL disorders , *ESOPHAGEAL abnormalities , *DIAGNOSIS - Abstract
Background Distensibility evaluation of the esophageal body using the functional lumen imaging probe ( FLIP) offers an objective measure to characterize patients with eosinophilic esophagitis (EoE), though this analysis may be limited by unrecognized catheter movement and esophageal contractility. The aims of this study were to report novel FLIP analytic methods of esophageal distensibility measurement in EoE and to assess the effect of contractility. Methods Nine healthy controls (six female; ages 20-49) and 20 EoE patients (four female; ages 19-64; grouped by degree of distension-mediated contractility identified on FLIP) were evaluated with a 16-cm FLIP device during step-wise balloon distension during upper endoscopy. A distensibility plateau ( DP) was generated using multiple methods to identify the narrowest esophageal body diameter: (i) wavelet decomposition ( WD), (ii) maximal diameter ( MD), and (iii) FLIP Analytics software. Key Results Distensibility was reduced in EoE patients compared with controls using the WD ( p = 0.002) and MD ( p = 0.001) methods; a trend was detected using the FLIP Analytics method ( p = 0.055). Significant intra-subject differences were detected between methods among both patients and controls ( p-values <0.001 to 0.025); the difference was more pronounced among subjects with a greater degree of contractility. DP was <19 mm among 7/9 controls with FLIP Analytics, 6/9 controls with WD, and 0/9 controls using the MD method. Conclusions & Inferences Distension-mediated contractility affects distensibility measurement with the FLIP. Using software-based algorithms, particularly with a method that identifies the maximal-achieved diameters ( MD), may improve objective distensibility measurement for clinical research and practice. [ABSTRACT FROM AUTHOR]
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- 2016
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18. The association between systemic sclerosis disease manifestations and esophageal high-resolution manometry parameters.
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Kimmel, J. N., Carlson, D. A., Hinchcliff, M., Carns, M. A., Aren, K. A., Lee, J., and Pandolfino, J. E.
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SYSTEMIC scleroderma , *ESOPHAGEAL motility , *MANOMETERS , *INTERSTITIAL lung diseases , *DEGLUTITION disorders - Abstract
Background We aimed to evaluate the associations between systemic sclerosis ( SSc)-related systemic manifestations and esophageal function using high-resolution manometry ( HRM). Methods Patients with SSc that had undergone HRM between 1/2004 and 9/2014 were identified and HRMs were analyzed according to the Chicago Classification. Clinical characteristics were identified via retrospective chart review and compared among motility diagnoses while adjusting for age, gender, race, and SSc-disease duration. Key Results Seventy-nine patients (85% female, ages 25-77) were included. Clinical characteristics were compared between patients with absent contractility ( AC, n = 40), ineffective esophageal motility ( IEM; n = 15), and normal motility ( n = 19); the five remaining patients met criteria for other motility diagnoses. Groups differed in severity of skin involvement measured by the modified Rodnan skin score (0-51): AC (adjusted mean 12.6), IEM (4.4), normal (4.3), p = 0.043. Pulmonary function tests [percent predicted FVC and DLCO) were lower in AC (adjusted mean, FVC: 70.3, DLCO 51.1), than IEM ( FVC: 92.0; DLCO: 76.9) and normal motility ( FVC: 80.0; DLCO: 67.2), p values 0.057 ( FVC) and 0.007 ( DLCO). Groups did not differ by SSc-disease duration, autoantibodies, or reported symptoms of dysphagia or reflux. Conclusions & Inferences In patients with SSc, absent esophageal contractility on HRM was associated with increased skin disease severity and worse lung function. Obtaining HRM to identify SSc patients with more severe esophageal dysfunction could be considered to enable implementation of management strategies in patients potentially at risk for increased morbidity and mortality. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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19. Esophageal diverticula are associated with propagating peristalsis: a study utilizing high-resolution manometry.
- Author
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Carlson, D. A., Gluskin, A. B., Mogni, B., Koo, J., Sood, R., Lin, Z., and Pandolfino, J. E.
- Subjects
- *
ESOPHAGEAL achalasia , *DIVERTICULOSIS , *ESOPHAGEAL diverticula , *TOPOGRAPHY , *ESOPHAGOGASTRIC junction - Abstract
Background Esophageal diverticula have been associated with esophageal motility disorders, most commonly achalasia. We aimed to evaluate high-resolution manometry ( HRM) motility diagnoses and pressurization patterns in patients with esophageal diverticula. Methods Patients were retrospectively identified for distal esophageal diverticula and previously completed HRM. High-resolution manometries were analyzed according to the Chicago Classification, and the pressure slope of the compartmentalization phase (time between upper esophageal sphincter closure and the transition zone) of esophageal bolus transit was measured. Pressure slopes were also measured in 10 asymptomatic volunteers (controls) for comparison. Key Results Nineteen patients (ages 31-83) were included. Eight (42%) patients had normal motility, five (26%) had esophagogastric junction outflow obstruction, and two (11%) had jackhammer esophagus; four patients had other motility diagnoses including only one patient with achalasia. A total of six patients (32%) had at least one hypercontractile swallow. Greater compartmentalization phase pressure slopes were observed in patients at the mid-esophageal body in both supine (median [interquartile range]: 1.9 mmHg/s [0.9, 3.6]) and upright (1.1 [0.1, 3.1]) positions than in controls (supine: −1.3 [−2.4, −0.11], p = 0.001; upright; −0.71 [−2.1, −0.02], p = 0.005). Conclusions & Inferences Propagating peristalsis, often with hypercontractility, was commonly seen in our cohort of patients with esophageal diverticula. Abnormal compartmentalization phase pressurization may indicate a relationship of abnormal esophageal wall mechanics and/or compliance with diverticula; however whether these findings are causal or reactionary remains unclear. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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20. High-resolution impedance manometry measurement of bolus flow time in achalasia and its correlation with dysphagia.
- Author
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Lin, Z., Carlson, D. A., Dykstra, K., Sternbach, J., Hungness, E., Kahrilas, P. J., Ciolino, J. D., and Pandolfino, J. E.
- Subjects
- *
ESOPHAGEAL achalasia , *DEGLUTITION disorders , *ESOPHAGUS , *ESOPHAGOGASTRIC junction , *TOPOGRAPHY - Abstract
Background We assessed whether a high-resolution impedance manometry ( HRIM) metric, bolus flow time ( BFT) across the esophagogastric junction ( EGJ), was abnormal in achalasia patients subtyped by the Chicago Classification and compared BFT to other HRM metrics. Methods HRIM studies were performed in 60 achalasia patients (14 type I, 36 type II and 10 type III) and 15 healthy controls. Studies were analyzed with a MATLAB program to calculate BFT using a virtual HRIM sleeve. Integrated relaxation pressure ( IRP) and basal end-expiratory EGJ pressure were also calculated. The relationship between BFT and dysphagia symptom scores was assessed using the impaction dysphagia questionnaire ( IDQ). Key Results Median BFT was significantly lower in achalasia patients (0.5 s, range 0.0-3.5 s) compared to controls (3.5 s, range 2.0-5.0 s; p < 0.05). BFT was significantly lower in types I and II than in type III achalasia in both the supine and upright positions ( p < 0.0001). BFT was the only HRIM metric significantly associated with IDQ score in both the supine ( R2 = 0.20, p = 0.0046) and upright positions ( R2 = 0.27, p = 0.0002). Conclusions & Inferences BFT was significantly reduced in all subtypes of achalasia and complementary to the IRP as a diagnostic discriminant in equivocal achalasia cases. Additionally, BFT had a more robust correlation with dysphagia severity compared to other metrics of EGJ function. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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21. Utilizing functional lumen imaging probe topography to evaluate esophageal contractility during volumetric distention: a pilot study.
- Author
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Carlson, D. A., Lin, Z., Rogers, M. C., Lin, C. Y., Kahrilas, P. J., and Pandolfino, J. E.
- Subjects
- *
ESOPHAGEAL motility , *PERISTALSIS , *MUSCLE contraction , *ESOPHAGEAL motility disorders , *PILOT projects , *DIAGNOSIS - Abstract
Background The functional lumen imaging probe ( FLIP) measures luminal cross-sectional area and pressure during volumetric distension. By applying novel customized software to produce FLIP topography plots, organized esophageal contractility can be visualized and analyzed. We aimed to describe the stimulus thresholds and contractile characteristics for distension-induced esophageal body contractility using FLIP topography in normal controls. Methods Ten healthy controls were evaluated during endoscopy with FLIP. During stepwise bag distension, simultaneous intra-bag pressure and luminal diameter measurements were obtained and exported to a MatLab program to generate FLIP topography plots. The distension volume, intra-bag pressure, and maximum esophageal body diameters were measured for the onset and cessation of repetitive antegrade contractions ( RACs). Contraction duration, interval, magnitude, and velocity were measured at 8 and 3-cm proximal to the esophagogastric junction. Key Results Eight of ten subjects demonstrated RACs at a median onset volume of 29 mL ( IQR: 25-38.8), median intra-bag pressure of 10.7 mmHg ( IQR: 8.6-15.9), and median maximum esophageal body diameter of 18.5 mm ( IQR: 17.5-19.6). Cessation of RACs occurred prior to completion of the distension protocol in three of the eight subjects exhibiting RACs. Values of the RAC-associated contractile metrics were also generated to characterize these events. Conclusions & Inferences Distension-induced esophageal contractions can be assessed utilizing FLIP topography. RACs are a common finding in asymptomatic controls in response to volume distention and have similar characteristics to secondary peristalsis and repetitive rapid swallows. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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22. High voltage GaN-on-silicon HEMT.
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Boles, T., Varmazis, C., Carlson, D., Palacios, T., Turner, G. W., and Molnar, R. J.
- Abstract
M/A-COM Technology Solutions has continued in the joint development efforts sponsored by the Department of Energy with MIT main campus and MIT Lincoln Labs to develop GaN on silicon three terminal high voltage/high current HEMT switching devices. The first year developmental goals were for a three terminal structure that has a reverse breakdown characteristic of >1200 V and is capable of switching 10 amperes of current. An average three terminal breakdown of 1322 V was achieved on a single finger 250 µm GaN on silicon HEMT device utilizing a source connected field plate with a 4.5 µm drain region overlap. An individual device breakdown on a single finger 250 µm GaN on silicon HEMT device with a SCFP of >1630 V was measured at a current of 250 µA (1mA/mm) - One of the highest yet reported for GaN on silicon in the industry. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]
- Published
- 2013
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23. AlGaAs anode heterojunction PIN diodes.
- Author
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Boles, T., Brogle, J., Hoag, D., and Carlson, D.
- Abstract
This paper describes the development of a heterojunction AlGaAs/GaAs PIN diode as a revolutionary improvement as compared to the homojunction GaAs PIN diode commonly used in microwave systems for commercial and military applications. In a heterojunction device the injected carriers from the junction are confined by the bandgap discontinuity between the AlGaAs/GaAs layers. This confinement effectively reduces the series resistance within the I-region of a PIN diode. Simulations of both single and double heterojunction PIN diodes predict a significant improvement in the return loss and insertion loss as compared to an equivalent GaAs PIN structure. In particular, the single heterojunction PIN diode, when simulated at a bias of 10 mA, indicates a factor of two reduction in high frequency insertion loss. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]
- Published
- 2013
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24. >1200 V GaN-on-silicon Schottky diode.
- Author
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Boles, T., Varmazis, C., Carlson, D., Palacios, T., Turner, G. W., and Molnar, R. J.
- Abstract
M/A-COM Technology Solutions has continuing joint development efforts sponsored by the Department of Energy with MIT main campus and MIT Lincoln Laboratory to develop GaN on silicon two and three terminal high voltage/high current switching devices. The initial developmental goals were for a Schottky diode that has a reverse breakdown blocking voltage of >600 V and is capable of handling 10 A of forward current. A comparison of the M/A-COM Technology Solutions lateral GaN Schottky diode on-resistance as a function of reverse breakdown voltage for a number of both lateral and vertical GaN Schottky diode geometries taken from the literature is presented. The substrates employed for all of these data points are either sapphire, SiC, silicon, and even one study which utilized single crystal GaN. Also included in this plot are theoretical limits for the basic materials typically used in GaN Schottky diode construction. It can be seen that the reverse breakdown results of approximately 1500 V for M/A-COM Technology Solutions lateral anode connected field GaN Schottky diodes on silicon substrates compare extremely favorably with the reported performance of the state-of-the-art devices, regardless of substrate material or design geometry. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]
- Published
- 2013
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25. Localizing the contractile deceleration point (CDP) in patients with abnormal esophageal pressure topography.
- Author
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Lin, Z., Pandolfino, J. E., Xiao, Y., Carlson, D., Bidari, K., Escobar, G., and Kahrilas, P. J.
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GASTROINTESTINAL motility ,ESOPHAGUS ,PERISTALSIS ,ESOPHAGOGASTRIC junction ,ALGORITHMS ,ANATOMY - Abstract
Background The contractile deceleration point (CDP) is an important landmark for interpreting esophageal pressure topography (EPT) plots. Previous analysis in normal subjects confirmed that the CDP could be localized using an algorithm that found the time during peristalsis at which a maximal length of the distal esophagus was contracting concurrently (tML method). This study aimed to test the tML method for localizing CDP in patients with abnormal motility. Methods High-resolution manometry studies of 75 patients with normal and disordered peristalsis were analyzed. Two experts, JEP and YX, used the original tangent-intersection method to score CDP coordinates for the first two swallows of each study. Alternative computerized algorithms tested against the expert were: (i) the tML method, (ii & iii) the intercept between the leading edge of the 30-mmHg isobaric contour and a line 2.0 cm (or 10% of esophageal length) proximal to the esophagogastric junction (EGJ) at rest, or (iv) the 'tML-3 cm' method, which added the stipulation that the CDP be within 3 cm of the EGJ. Key Results All tested algorithms were highly correlated with the expert. However, the tMl-3 cm method was better in the sense that it eliminated outliers (>1 s discrepancy with the expert) that occurred with the other methods usually attributable to weak distal peristalsis. Conclusions & Inferences Optimal automated CDP localization was achieved in both normal and a spectrum of abnormal motility using the tML method with the added stipulation that the CDP be restricted to within the distal 3 cm of the EGJ at rest. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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26. Refining the criterion for an abnormal Integrated Relaxation Pressure in esophageal pressure topography based on the pattern of esophageal contractility using a classification and regression tree model.
- Author
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Lin, Z., Kahrilas, P. J., Roman, S., Boris, L., Carlson, D., and Pandolfino, J. E.
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ESOPHAGEAL achalasia ,MEDICAL geography ,ESOPHAGOGASTRIC junction ,GASTROINTESTINAL motility ,CONTRACTILITY (Biology) - Abstract
Background The Integrated Relaxation Pressure (IRP) is the esophageal pressure topography (EPT) metric used for assessing the adequacy of esophagogastric junction (EGJ) relaxation in the Chicago Classification of motility disorders. However, because the IRP value is also influenced by distal esophageal contractility, we hypothesized that its normal limits should vary with different patterns of contractility. Methods Five hundred and twenty two selected EPT studies were used to compare the accuracy of alternative analysis paradigms to that of a motility expert (the 'gold standard'). Chicago Classification metrics were scored manually and used as inputs for MATLAB™ programs that utilized either strict algorithm-based interpretation (fixed abnormal IRP threshold of 15 mmHg) or a classification and regression tree (CART) model that selected variable IRP thresholds depending on the associated esophageal contractility. Key Results The sensitivity of the CART model for achalasia (93%) was better than that of the algorithm-based approach (85%) on account of using variable IRP thresholds that ranged from a low value of >10 mmHg to distinguish type I achalasia from absent peristalsis to a high value of >17 mmHg to distinguish type III achalasia from distal esophageal spasm. Additionally, type II achalasia was diagnosed solely by panesophageal pressurization without the IRP entering the algorithm. Conclusions & Inferences Automated interpretation of EPT studies more closely mimics that of a motility expert when IRP thresholds for impaired EGJ relaxation are adjusted depending on the pattern of associated esophageal contractility. The range of IRP cutoffs suggested by the CART model ranged from 10 to 17 mmHg. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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27. Effects of quinoa hull meal on piglet performance and intestinal epithelial physiology.
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Carlson, D., Fernandez, J. A., Poulsen, H. D., Nielsen, B., and Jacobsen, S.-E.
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- *
SWINE nutrition , *PIGLETS , *QUINOA , *FEED additives , *EPITHELIAL cells , *GLUCOSE transporters , *SEROTONIN , *INTESTINAL physiology - Abstract
Summary Saponin-containing feed additives have shown positive effects on pig performance. Quinoa hull has high saponin content and may be of interest as a feed additive. This study aimed to evaluate quinoa hull meal (QHM) as a feed additive in a pig diet. The effects of QHM were assessed for three dosages of South American (SA) origin (100, 300 and 500 mg/kg) and one dosage of Danish (DK) quinoa (300 mg/kg). In addition, the effect of dietary SA-QHM and SA-QHM-extract on jejunal epithelial physiology was studied ex vivo in Ussing chambers. The experiment included 400 piglets weaned at 28 ± 2 days of age and the experimental period was 4 weeks. Piglets were weighed initially and finally and feed intake registered. The ex vivo studies were performed with epithelium from 40 pigs receiving control or SA-QHM. Epithelium from each pig was placed into eight Ussing chambers, where four concentrations of SA-QHM-extract were added. Epithelial permeability, Na+-dependent glucose transport and serotonin (5-HT) and theophylline-induced secretion were measured. The results showed that QHM had no influence on piglet's growth (p = 0.41) or feed intake (p = 0.17). In spite of a large difference in saponin content between SA-QHM and DK-QHM (28.7% and 2.0% w/w respectively) the source did not affect pig performance. The ex vivo studies revealed no effect (p > 0.05) of adding QHM-extract into the medium. The permeability and glucose induced absorption were highest (p = 0.003 and p = 0.04 respectively) in epithelium from pigs that consumed 100 or 300 mg/kg SA-QHM. The secretory response to 5-HT was not affected (p = 0.59) by dietary treatments, but the theophylline-induced secretion decreased (p = 0.02) with increasing dietary SA-QHM. The changes in epithelial physiology measured ex vivo did not affect animal performance in vivo in this study. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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28. Determination by HPLC fluorescence analysis of the natural enantiomers of sex pheromones in the New World screwworm fly, Cochliomyia hominivorax.
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Akasaka, K., Carlson, D. A., Ohtaka, T., Ohrui, H., Mori, K., and Berkebile, D. R.
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- *
SCREWWORM , *PHEROMONES , *ENANTIOMERS , *HIGH performance liquid chromatography , *FLIES , *CELL polarity - Abstract
Bioassays of six racemic synthesized candidate sex pheromone compounds against male New World screwworm Cochliomyia hominivorax (Coquerel) flies showed that the most potent bioactivity was found with 6-acetoxy-19-methylnonacosane and 7-acetoxy-15-methylnonacosane compared with four other isomeric acetoxy nonacosanes and a larger aliphatic ketone. As all these methyl-branched compounds have two asymmetric carbons and four possible enantiomers, characterization of the natural enantiomers was essential. All four enantiomers for the two most bioactive isomers of the natural sex pheromone were synthesized for bioassay. Hydrolysis and derivatization of these enantiomers with different fluorescent reagents was followed by column-switched high-performance liquid chromatography. The use of two linked, reversed-phase columns of different polarity held at sub-ambient temperatures allowed good separation of each enantiomer. This analysis applied to natural material was successful, as (6 R,19 R)-6-acetoxy-19-methylnonanocosane, and (7 R,15 R)- and (7 R,15 S)-7-acetoxy-15-methylnonanocosane were detected in extracts of recently colonized female flies. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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29. Application of the Sleeping Beauty transposon system to avian cells.
- Author
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Kong, B.-W., Carlson, D. F., Fahrenkrug, S. C., and Foster, D. N.
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TRANSPOSONS , *DRUG resistance in microorganisms , *GENE transfection , *CHICKENS , *EMBRYOS - Abstract
We have for the first time assessed the ability of the Sleeping Beauty (SB) transposon system to enhance transgenesis in chicken and turkey cells. The efficiency of transgenesis with a transposon encoding an antibiotic resistance gene was dramatically enhanced 15- to 35-fold when transposase was supplied by co-transfection of immortalized chicken and turkey cells with a construct encoding SB. In contrast, transgenesis of primary chicken embryo fibroblast (CEF) cells was not significantly increased by providing transposase, suggesting that the benefits of transposon–transgenesis in primary avian cells will require the application of more efficient transfection methods, further enhanced SB transposase or an alternative transposon system. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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30. Tsetse and other biting fly responses to Nzi traps baited with octenol, phenols and acetone.
- Author
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MIHOK, S., CARLSON, D. A., and NDEGWA, P. N.
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TSETSE-flies , *STABLE fly , *INSECT traps , *PHENOLS , *ACETONE , *ENTOMOLOGY research - Abstract
Octenol (1-octen-3-ol), acetone, 4-methylphenol, 3-n-propylphenol, and other potential attractants (human urine, stable fly faeces), as well as guiacol, creosol (potential repellents), were tested as baits for biting flies in North America using standard phthalogen blue IF3GM cotton Nzi traps, or similar commercial polyester traps. Baits were tested during the summers of 2001–04 at a residence in Canada and during January–August 2001 at a dairy in the U.S.A. Behaviour in the presence of octenol was also studied by intercepting flies approaching a trap through the use of transparent adhesive film. Analogous bait and/or trap comparisons were conducted in natural settings in June 1996 in Kenya and in September–December 1997 in Ethiopia. In Canada, catches of five of six common tabanids ( Tabanus similis Macquart, Tabanus quinquevittatus Wiedemann, Hybomitra lasiophthalma [Macquart], Chrysops univittatus Macquart, Chrysops aberrans Philip) and the stable fly Stomoxys calcitrans L. were increased significantly by 1.2–2.1 times with octenol (1.5 mg/h). Catches of T. quinquevittatus and S. calcitrans were 3.5–3.6 times higher on a sticky enclosure surrounding a trap baited with octenol. No other baits or bait combinations had an effect on trap catches in North America. In Ethiopia, standard Nzi traps baited with a combination of acetone, octenol and cattle urine caught 1.8–9.9 times as many Stomoxys as similarly baited epsilon, pyramidal, NG2G, S3, biconical and canopy traps, in order of decreasing catch. When baits were compared, catches in Nzi traps of six stable fly species, including S. calcitrans, were not affected by octenol (released at approximately 1 mg/h), or cattle urine (140 mg/h), used alone or in combination with acetone (890 mg/h). Acetone alone, however, significantly increased the catches of common Stomoxys such as Stomoxys niger niger Macquart, Stomoxys taeniatus Bigot, and S. calcitrans by 2.4, 1.6 and 1.9 times, respectively. Catches of Glossina pallidipes Austen were increased significantly in traps baited with acetone, urine or octenol, or any combination, relative to those in unbaited traps (1.4–3.6x). Catches of Glossina morsitans submorsitans Newstead were increased significantly by 1.5–1.7 times, but only when baits were used individually. Unlike other studies with East African tsetse, catches of both tsetse species with the complete bait combination (acetone, urine and octenol) did not differ from those in unbaited traps. Experiments with an incomplete ring of electric nets surrounding a Nzi trap, and a new approach using a sticky enclosure made from transparent adhesive film, revealed diverse responses to artificial objects and baits among biting flies. In Kenya, daily trap efficiency estimates for traps baited with either carbon dioxide (6 L/min) or a combination of acetone, cattle urine and octenol were 21–27% for G. pallidipes, 7–36% for Glossina longipennis Corti, 27–33% for S. n. niger, and 19–33% for Stomoxys niger bilineatus Grünberg, assuming 100% electrocution efficiency. Actual trap efficiencies may have been lower, given observed outside : inside electric net catch ratios of 0.6 : 1.6. Observed ratios averaged 54% of expected values, with 10 of 15 possible ratios less than the minimum possible value of 1.0. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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31. Candidate sex pheromones of the New World screwworm Cochliomyia hominivorax.
- Author
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CARLSON, D. A., BERKEBILE, D. R., SKODA, S. R., MORI, K., and MIHOK, S.
- Subjects
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PHEROMONES , *SCREWWORM , *BLOWFLIES , *KETONES , *ANIMAL sexual behavior , *TARTARIC acid - Abstract
Five novel homologous acetate derivatives of long-chain secondary alcohols and a related ketone were tested for their efficacy as contact mating stimulants for Cochliomyia hominivorax Coquerel (Diptera: Calliphoridae). Full copulatory behaviour at a high percentage was found in tests with racemic 6-acetoxy-19-methylnonacosane at 2.5–20 μg using fertile males from three strains. Males of two strains responded nearly as well to 7-acetoxy-15-methylnonacosane, but an older strain first colonized in 1992 did not respond to this compound. Few or no copulatory responses were obtained to the other secondary alcohol acetates and a related ketone. These two acetate derivatives are the first sex pheromones identified in a calliphorid fly. The threshold of response was also tested, but could not be pinpointed. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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32. Assessment of zinc and copper status in weaned piglets in relation to dietary zinc and copper supply.
- Author
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Carlson, D., Beattie, J. H., and Poulsen, H. D.
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REQUIREMENTS for animal nutrition , *COPPER in animal nutrition , *ZINC , *PIGLETS , *INTESTINAL mucosa , *ALKALINE phosphatase , *MESSENGER RNA - Abstract
The aim of the study was to determine the effect of weaning and the effect of increasing dietary zinc concentrations on the zinc and copper status of weaned piglets (study 1) and to study the effect of high concentrations of dietary zinc and/or copper on zinc and copper status of weaned piglets (study 2). Study 1 included 54 piglets (six litters of nine piglets). One piglet from every litter was killed 1 day before weaning. The remaining 48 piglets were allocated at weaning (28 days) to four dietary zinc treatments (100, 250, 1000 or 2500 ppm) and subsequently killed 1–2, 5–6 or 14–15 days after weaning. Study 2 included 48 piglets (six litters of eight piglets) allocated to four dietary treatments, consisting of low or high dietary zinc (100 or 2500 ppm) in combination with low or high dietary copper (20 or 175 ppm). All piglets in study 2 were killed 5–7 days after weaning. In both studies, the trace mineral status was assessed by zinc and copper concentrations and alkaline phosphatase (AP) activity in plasma and mucosal tissue. In study 2, lymphocyte metallothionein (MT) mRNA and intestinal mucosa MT mRNA concentrations were included as zinc status markers. The results showed that the zinc status, measured as zinc in plasma and mucosa, was not affected by weaning of the piglets. Plasma copper concentrations decreased during the first 2 weeks after weaning. High dietary copper concentrations did not affect the concentration of copper in plasma, but increased the concentration of copper in mucosa and the concentration of zinc in plasma. The dietary zinc treatments increased the zinc concentration in plasma as well as the zinc and MT mRNA concentration in mucosa. Lymphocyte MT mRNA concentrations did not reflect the differences in dietary zinc supplementation. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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33. Sex pheromone of the tsetse species, Glossina austeni: isolation and identification of natural hydrocarbons, and bioassay of synthesized compounds.
- Author
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Carlson, D. A., Mramba, F., Sutton, B. D., Bernier, U. R., Geden, C. J., and K. Mori
- Subjects
- *
TSETSE-flies , *PHEROMONES , *SEX recognition (Zoology) , *HORMONES , *CHROMATOGRAPHIC analysis , *ORGANIC compounds - Abstract
Copulatory responses of male Glossina austeni (Newstead) (Diptera: Glossinidae), that were elicited after contact with frozen female tsetse, were not observed after solvent washing of cuticular lipids. Chromatographic analysis of extracts from laboratory-reared and field-collected G. austeni females yielded natural hydrocarbons that were highly stimulatory to males. Most of this activity was produced by compounds in the alkene fraction. Gas chromatograms (GC) contained five natural alkenes; these were separated by preparative GC for bioassays conducted in Tanzania. The two major alkenes were identified using gas chromatography–mass spectrometry (GC–MS) to be 13,17-dimethyltritriacont-1-ene and 13,17-dimethylpentatriacont-1-ene, after the samples had undergone derivatization using dimethyl disulphide and saturation with deuterium. These alkenes and natural alkanes were quantified from G. austeni of both sexes from laboratory and field samples to confirm that their presence was consistent in this species. Trials of synthetic samples resulted in the order of biological activity for the stereoisomers of 13,17-dimethyltritriacont-1-ene as follows: S, R-33:1 > R, S- 33:1 > S, S-33:1 > R, R-33:1. Dose–response data showed an ED50 at 5 µg per treated, solvent-washed male decoy. Of the four stereoisomers of 13,17-dimethylpentatriacont-1-ene, R, R-35:1 showed the most activity. This is the first report of alkene-induced sexual activity in males of the genus Glossina. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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34. Additional dietary zinc for weaning piglets is associated with elevated concentrations of serum IGF-I.
- Author
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Carlson, D., Poulsen, H. D., and Vestergaard, M.
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ZINC , *PIGLETS , *SERUM , *SOIL composition , *INGESTION , *ANIMAL nutrition - Abstract
Two experiments were performed in order to study how weaning and post-weaning dietary zinc level affect serum IGF-I. Further, whether the growth-enhancing effect of 2500 ppm of dietary zinc (Zn2500) and/or 175 ppm of dietary copper (Cu175) in post-weaning diets is associated with elevated serum IGF-I levels in piglets was studied. Experiment 1 included 54 piglets (six litters of nine piglets). One piglet from every litter was assigned to a control group (blood sampled 1 day before weaning). At weaning the remaining eight piglets from every litter were allocated randomly to four dietary treatments with increasing zinc inclusions (Zn100, Zn250, Zn1000, Zn2500). In exp. 2, 48 piglets (six litters of eight piglets) were allocated to four dietary treatments (Zn100, Zn100Cu175, Zn2500, Zn2500Cu175). All piglets in exp. 1 were blood sampled at )1, 1–2, 5–6 or 14–15 days after weaning and in exp. 2 blood samples were taken from all pigs 5–7 days after weaning. Feed intake was recorded per pen (two piglets) and weight gain was recorded for every piglet. Just after weaning feed intake was very low, piglets lost weight and serum IGF-I decreased in exp. 1. However, the piglets fed 2500 ppm of zinc reached pre-weaning levels of serum IGF-I at 14–15 days post-weaning, whereas piglets receiving lower zinc levels showed no changes in serum IGF-I. In exp. 2, additional dietary zinc in weaning diets for piglets was found to be associated with increased feed intake, improved growth rate and increased serum IGF-I. High levels of dietary copper did not affect any of these measurements. Zinc-induced rise in serum IGF-I was partly due to increased feed intake. After correcting for differences in feed intake, zinc significantly increased serum IGF-I. However, to completely separate effects of feed intake from effects of zinc status, pair-feeding should be considered in future studies. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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35. General competencies are intrinsic to emergency medicine training: a multicenter study.
- Author
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Reisdorff EJ, Hayes OW, Reynolds B, Wilkinson KC, Overton DT, Wagner MJ, Kowalenko T, Portelli D, Walker G, and Carlson D
- Published
- 2003
36. Tgf-beta1, Tgf-beta2, Tgf-beta3 and Msx2 expression is elevated during frontonasal suture morphogenesis and during active postnatal facial growth.
- Author
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Adab, K, Sayne, J R, Carlson, D S, and Opperman, L A
- Subjects
RNA analysis ,ANIMAL experimentation ,COMPARATIVE studies ,FACIAL bone growth ,GENE expression ,GROWTH factors ,IMMUNOHISTOCHEMISTRY ,RESEARCH methodology ,MEDICAL cooperation ,MORPHOGENESIS ,NASAL bone ,POLYMERASE chain reaction ,PROTEINS ,RATS ,RESEARCH ,SKULL ,DNA-binding proteins ,EVALUATION research ,REVERSE transcriptase polymerase chain reaction ,FRONTAL bone - Abstract
Objectives: It is hypothesized that regulation of facial suture morphogenesis is similar to that of cranial sutures, with expression of similar regulatory molecules, governing suture formation and patency. The present study was designed to characterize the morphology of the frontonasal (FN) suture of the rat at different developmental stages and to investigate the presence and temporal-spatial expression of transforming growth factor-beta 1 (Tgf-beta1), Tgf-beta2, Tgf-beta3 and Msx2 mRNA within these structures.Setting and Sample Population: The Department of Biomedical Sciences at Texas A&M University System Health Science Center, Baylor College of Dentistry, Dallas, TX USA. Histological sections and RNA isolated from FN suture tissues of Sprague-Dawley rats, aged embryonic day 16 through postnatal day 20.Method: Sections were examined after immunohistochemical staining. Gene expression was determined by densitometric analysis of RT-PCR products run on agarose gels.Results: FN sutures develop slightly later than cranial sutures and show increased complexity over time when compared to cranial sutures. FN sutures were closely associated with the nasal capsular cartilage, with intervening layers of perichondrium and periosteum. The pattern of expression of Tgf-betas within the FN suture tissues was similar to that seen in the cranial sutures. However, mRNA and protein of the Tgf-betas were differentially expressed over time compared to cranial sutures. In FN sutures, Tgf-beta mRNA levels were elevated both during the period of suture morphogenesis and during active bone growth from the suture in the early postnatal period. Msx2 mRNA expression was elevated in both the prenatal and postnatal periods, similar to Tgf-beta mRNA expression.Conclusion: Tgf-beta and Msx2 are present in facial sutures similar to cranial sutures, but are differentially expressed over time, perhaps reflecting different bone growth rates from these sutures. [ABSTRACT FROM AUTHOR]- Published
- 2002
- Full Text
- View/download PDF
37. Femur length and trisomy 21: impact of gestational age on screening efficiency.
- Author
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Snijders, R. J. M., Platt, L. D., Greene, N., Carlson, D., Krakow, D., Gregory, K., and Bradley, K.
- Subjects
DOWN syndrome ,FEMUR ,PRENATAL diagnosis ,GESTATIONAL age - Abstract
This study assesses two methods used to define relatively short femur in screening for trisomy 21 and examines changes in performance of screening with gestational age. Retrospective analysis of data on menstrual age, femur length (FL) and biparietal diameter (BPD) in 49 trisomy 21 pregnancies and 6069 normal controls. Reference ranges were derived for BPD/FL versus menstrual age and for FL versus BPD. Two methods of defining short femur (BPD/FL and observed-to-expected FL ratio) were examined for false-positive rates and detection rates for trisomy 21 at different gestational ages. In the control group the BPD/FL ratio and its standard deviation decreased with menstrual age. Trisomy 21 was associated with a significantly higher BPD/FL ratio (P < 0.001) and the deviation increased significantly with menstrual age (P < 0.05). Eleven percent of 28 fetuses examined at 15–17 weeks had a BPD/FL above the 95th centile compared with 24% of 21 fetuses examined at 18–20 weeks (P = 0.40). The median observed-to-expected FL ratio in the control group was 1.0 throughout the gestational age range but the standard deviation decreased significantly with menstrual age (P < 0.01). Trisomy 21 was associated with a significantly reduced observed-to-expected FL ratio (P < 0.001) and the deviation increased significantly with menstrual age (P < 0.05). A fixed cut-off of 0.91 for observed-to-expected FL ratio provided a false-positive rate of 12% at 15–17 weeks compared with 6% at 18–20 weeks of gestation (P < 0.001) with detection rates of 29 and 38%, respectively (P = 0.73). Irrespective of the definition used to define the condition, relatively short femur is a poor marker for trisomy 21 particularly when the assessment takes place before 18 weeks of gestation. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
38. Characterization and specificity of a high titre polyclonal goat anti-murine IL-1 antibody.
- Author
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Scheetz, M. E., Carlson, D. G., Bobbitt, J. L., Butler, L. D., and Zuckerman, S. H.
- Subjects
- *
IMMUNOGLOBULINS , *GOATS , *IMMUNIZATION , *CELL lines , *MACROPHAGES , *MOLECULAR weights - Abstract
The immunization of goats with an HPLC-purified IL-1 preparation derived from the supernatants of LPS-induced P388D1 cultures has resulted in the derivation of a high titre antiserum specific for murine IL-1. This antiserum exhibits a 50% inhibition of an IL-1-dependent thymocyte costimulation assay at a reciprocal dilution of 30,000 and antibody activity is still detected at 100,000-fold dilution. The goat anti-murine IL-1 serum is specific for murine IL-1 synthesized by several murine macrophage cell lines and does not neutralize human, rabbit or porcine (catabolin) IL-1. The antiserum also inhibits antigen-induced proliferation of the D10.G4 helper T-cell line. In addition to the reaction against IL-1, the antiserum also detects three additional peptides with molecular weights between 20,000 and 30,000. [ABSTRACT FROM AUTHOR]
- Published
- 1986
39. HIGH PERFORMANCE MESFET POWER AMPLIFIERS FOR HIGH VOLUME APPLICATION IN Ka BAND.
- Author
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Mondal, J., Carlson, D., Pulver, C., Vickberg, M., and Geddes, J.
- Subjects
- *
RADIO frequency , *ELECTRIC power , *RADIO measurements , *FREQUENCIES of oscillating systems , *RADIO waves - Abstract
A very repeatable MBE power MMIC process has been developed for low-cost and high-volume Ka-band applications. The RF yield under power drive has reached more than 60%. The power out in a balanced configuration was 300 mW with 18% power added efficiency at 30 GHz. [ABSTRACT FROM AUTHOR]
- Published
- 1991
- Full Text
- View/download PDF
40. Electrophoretic analysis of four high molecular weight sialoglycoproteins produced by metastatic human colon carcinoma cells.
- Author
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Irimura, T., Carlson, D. A., and Ota, D. M.
- Published
- 1988
- Full Text
- View/download PDF
41. Sex pheromone perception by males of the tsetse fly, Glossina morsitans morsitans.
- Author
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LANGLEY, P. A., HUYTON, P. M., and CARLSON, D. A.
- Published
- 1987
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42. The role of sex pheromones in initiation of copulatory behaviour by male tsetse flies, Glossina morsitans morsitans.
- Author
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HUYTON, P. M., LANGLEY, P. A., CARLSON, D. A., and COATES, T. W.
- Published
- 1980
- Full Text
- View/download PDF
43. Specificity of contact sex pheromones in tsetse flies, Glossina spp.
- Author
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HUYTON, P. M., LANGLEY, P. A., CARLSON, D. A., and SCHWARZ, M.
- Published
- 1980
- Full Text
- View/download PDF
44. Anodic Proton Injection in Glasses.
- Author
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CARLSON, D. E.
- Published
- 1974
- Full Text
- View/download PDF
45. Ion Depletion of Glass at a Blocking Anode: I, Theory and Experimental Results for Alkali Silicate Glasses.
- Author
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CARLSON, D. E.
- Published
- 1974
- Full Text
- View/download PDF
46. Ion Depletion of Glass at a Blocking Anode: II, Properties of Ion-Depleted Glasses.
- Author
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CARLSON, D. E., HANG, K. W., and STOCKDALE, G. F.
- Published
- 1974
- Full Text
- View/download PDF
47. Bacillary angiomatosis in an HIV-positive patient. Good response to Dapsone.
- Author
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Fernandez-Bussy, R. A., Alonso, A. B., Carlson, D., Ramonda, S., Salerni, G., and Reeves, G.
- Subjects
ANGIOMATOSIS ,HIV ,DAPSONE ,LEPROSTATIC agents ,AZIDOTHYMIDINE ,CLINICAL indications - Abstract
Object Report the case of a 25 year old HIV patient who developed bacillary angiomatosis. Setting Department of Dermatology, Centenary Hospital, Rosario, Argentina. Objective The patient failed to respond to the standard treatment with erythromycin. Result The patient showed improved by the administration of Dapsone along with Zidovudine. Conclusion This case is reported both because it is a rarely seen disease as well as because a good therapeutic response is obtained. [ABSTRACT FROM AUTHOR]
- Published
- 1995
- Full Text
- View/download PDF
48. Cuticular hydrocarbons from six species of tephritid fruit flies.
- Author
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Carlson, D. A. and Yocom, S. R.
- Published
- 1986
- Full Text
- View/download PDF
49. Evaluation of serum visceral protein levels as indicators of nitrogen balance in thermally injured patients.
- Author
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Carlson, Dawn E., Cioffi, William G., Mason, Arthur D., Mcmanus, William F., Pruitt, Basil A., Carlson, D E, Cioffi, W G Jr, Mason, A D Jr, McManus, W F, and Pruitt, B A Jr
- Published
- 1991
- Full Text
- View/download PDF
50. Attempted suicide and immigration in Perth, Western Australia, 1969-1978.
- Author
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Burvill, P. W., Armstrong, B. K., and Carlson, D. J.
- Published
- 1983
- Full Text
- View/download PDF
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