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Transcatheter mitral valve repair (TMVr) has emerged as a safe and effective alternative to conventional surgery in patients with primary and secondary mitral regurgitation, especially those at high surgical risk. This review summarises alternative indications for TMVr outside of the traditional criteria derived from the major randomised trials and focusses on less common mitral valve anatomies such as commissural prolapse and bileaflet prolapse, patients with mitral annuloplasty rings, as well as acutely unwell patients with papillary muscle rupture and/or cardiogenic shock. Specific technical challenges involved in treating such patient groups are summarised and described., (Copyright © 2023 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Background: Several surgical and percutaneous treatments are available for patients with aortic valve disease., Aim: To establish whether trends in aortic valve replacements (AVR) in Australia reflect recent evidence., Methods: Using the Australian Institute of Health and Welfare data, this study calculated all AVR and balloon aortic valvuloplasty (BAV) procedures conducted in all Australian hospitals from 2004 to 2019. Linear regression analysis was performed to determine whether age-adjusted rates had changed over the study period., Results: There were 80 883 AVR performed. Of these, 66% were men and 64% were aged >70 years. Absolute rates of AVR increased from 3631 to 7277 with a significant 22% age-adjusted rise seen (1.9% increase per year (+0.26 per 100 000 per year; 95% confidence interval 0.19-0.34); P < 0.001). This trend was more pronounced in men than women and in those aged >80 years (+0.23 per 100 000 per year; P < 0.001). Proportion of mechanical AVR implanted fell from 38.4% to 8.6% (P < 0.001). A total of 2683 transcatheter aortic valve implantation (TAVI) procedures was performed in 2019, representing a 52% annual increase from 2014. BAV increased from 66 procedures in 2004 to 862 in 2019., Conclusion: Rates of AVR have increased significantly over the past 16 years, particularly in the elderly. Despite international guideline recommendations, fewer mechanical AVR are being used in younger cohorts. The uptake in TAVI rates might reflect evidence that suggests it is a safe alternative, at least in the medium term. BAV has also seen a resurgence during this time period., (© 2021 Royal Australasian College of Physicians.)

Coronary artery calcification is prevalent in coronary heart disease with its progression being predictive of future adverse cardiac events. Its presence is considered to be a marker of interventional procedural complexity. Several adjunctive percutaneous coronary intervention tools, such as modifying balloons, atherectomy devices and intravascular lithotripsy, now exist to successfully treat calcified lesions. In this state-of-the-art review, a step-wise progression of strategies is described to modify coronary plaque, from well-recognised techniques to techniques that should only be considered when standard manoeuvres have proven unsuccessful. Technology has advanced greatly over the past few decades and we discuss how future technologies might shape percutaneous intervention., (Copyright © 2022 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Background: COVID-19 has presented a unique set of psychological stressors for healthcare professionals. There is currently a dearth of literature establishing the impact amongst intensive care workers, who may be at the greatest risk. This study aimed to establish the prevalence of anxiety, depression and post-traumatic stress disorder amongst a cohort of intensive care workers within the United Kingdom., Methods: A questionnaire was designed to incorporate validated screening tools for depression (Patient Health Questionnaire, PHQ-9) anxiety (Generalised Anxiety Disorder Scale, GAD-7), and post-traumatic stress disorder (Impact of Event Scale-Revised, IES-R). All intensive care workers at the Countess of Chester Hospital (UK) were eligible. Data was collected between 17th June and 8th July 2020., Results: The majority of the 131 respondents were nurses (52.7% [69/131]) or doctors (32.8% [43/141]). Almost one-third (29.8% [39/131]) reported a significant or extreme impact of COVID-19 on their mental health. In total, 16%(21/131) had symptoms of moderate depression, 11.5%(15/131) moderately severe depression and 6.1%(8/131) severe depression. Females had significantly higher mean PHQ-9 scores than males (8.8 and 5.7 respectively, p = 0.009). Furthermore, 18.3% (24/131) had moderate anxiety with 14.5% (19/131) having severe anxiety. Mean GAD-7 scores were higher amongst females than males (8.7 and 6.3 respectively, p = 0.028). Additionally, 28.2% (37/131) reported symptoms consistent with a diagnosis of PTSD (IES-R ≥ 33). Despite these findings, only 3.1% (4/131) of staff accessed trust mental health support., Conclusion: The impact of COVID-19 on intensive care workers is significant and warrants specific focus and attention in order to preserve this key sector of the workforce., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Intensive Care Society 2021.)

A 53-year-old man with a background of acute myelomonocytic leukemia in remission presented with pleurisy. Repeat transthoracic echocardiography over several weeks revealed thickening left ventricular walls and decreasing systolic function. He died of decompensated heart failure due to cardiac myeloid sarcoma, with autopsy revealing an enlarged heart weighing >1 kg. ( Level of Difficulty: Intermediate. )., (© 2021 The Authors.)

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited., Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19., Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020., Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108)., Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%)., Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively., Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions., Trial Registration: ClinicalTrials.gov Identifier: NCT02735707.

Objectives: Determine whether an ultrathin biodegradable polymer sirolimus-eluting stent ('Orsiro'-BP-SES) has clinical benefits over second-generation durable polymer drug-eluting stents (DP-DES)., Methods: We conducted a prospective systematic review and meta-analysis of randomised clinical trials comparing Orsiro BP-SES against DP-DES (PROSPERO Registration: CRD42019147136). The primary outcome was target lesion failure (TLF): composite of cardiac death, target vessel myocardial infarction (TVMI) and clinically indicated target lesion revascularisation (TLR)) evaluated at the longest available follow-up., Results: Nine trials randomised 11 302 patients to either Orsiro BP-SES or DP-DES. At mean weighted follow-up of 2.8 years, the primary outcome (TLF) occurred in 501 of 6089 (8.2%) participants with BP-SES compared with 495 of 5213 (9.5%) participants with DP-DES. This equates to an absolute risk reduction of 1.3% in TLF in favour of Orsiro BP-SES (OR 0.82; 95% CI 0.69 to 0.98; p=0.03). This was driven by a reduction in TVMI (OR 0.80; 95% CI 0.65 to 0.98; p=0.03). There were no significant differences in other clinical endpoints: cardiac death, TLR and stent thrombosis., Conclusion: The Orsiro BP-SES shows promising clinical outcomes in patients undergoing percutaneous coronary intervention compared with contemporary second-generation DES at a short to medium term follow-up. More research is warranted to evaluate performance over a longer follow-up period and in different clinical and lesion subsets., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

A 77-year-old woman with obstructive sleep apnea presented with a 3-week history of leg swelling and dyspnea on exertion. She had a dry cough and lost 10 kg over the past 2 years. Examination revealed elevated jugular venous pressure, reduced air entry in the left lower-lung field, and pedal edema. Imaging with chest computed tomography revealed a giant pedunculated left atrial myxoma to be the cause of her severe pulmonary hypertension, which was reversible with treatment.

Background: Rotational atherectomy (RA) has been used in percutaneous coronary intervention (PCI) for 30 years. With advances in technology, this observational study looks at how rates of RA have changed over the past decade in Australia in relation to PCI and coronary artery bypass graft (CABG) rates., Methods: Retrospective analysis of RA, PCI, and CABG rates per Australian state from Australian Government Department of Human Services' data on Medicare items from 2007 to 2017 was carried out., Results: There were 149 RA procedures in 2007, increasing to 452 in 2017. Rotational atherectomy accounted for 0.67% of PCI procedures in 2007, increasing to 1.48% in 2018 (+0.81%, 95% confidence interval [CI] = [0.64%-0.91%]; P  < .001). Most of this increase has come from procedures in New South Wales (441% increase). Australian PCI rate increased from 22 301 to 30 480. Rate of CABG decreased from 5418 to 5206., Conclusions: From 2007 to 2017, rates of RA trebled in Australia. This is despite stable rates of PCI and a fall in rates of CABG. There are several clinical explanations for this trend., Competing Interests: Declaration of conflicting interests:The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: BG reports receiving proctorship fees for the WATCHMAN™ device (Boston Scientific Corporation). No other potential conflict of interest relevant to this article was reported.

Background: Pulmonary valve infective endocarditis is a rare diagnosis that is usually associated with immunocompromised states or structurally abnormal hearts. It is unusual for it to occur in structurally normal hearts or to cause recurrent symptoms after targeted antibiotics. Although guidelines suggest follow-up with repeat echocardiography and inflammatory marker surveillance, this case demonstrates that these are not always useful investigations, and instead imaging of the chest may be more appropriate., Case Presentation: We describe a case of a 74-year-old man who presented with respiratory symptoms and was originally misdiagnosed with pneumonia but later found to have a large pulmonary valve vegetation caused by Streptococcus mitis. Despite initially responding to antibiotic therapy, the vegetation continued to cause pulmonary emboli and cavitating lung abscesses months later, necessitating pulmonary valve replacement., Conclusions: This case demonstrates that pulmonary valve endocarditis can present atypically with recurrent respiratory symptoms, and in such cases, echocardiography should be considered to investigate for right-sided infective endocarditis. In addition, despite correct treatment, with normalization of inflammatory markers and improvement in vegetation size, infective endocarditis can continue to cause systemic symptoms. Finally, clinicians should consider chest computed tomography routinely as part of right-sided infective endocarditis follow-up.

The heterogeneity of an individual patient's tumor has been linked to treatment resistance, but quantitative biomarkers to rapidly and reproducibly evaluate heterogeneity in a clinical setting are currently lacking. Using established tools available in a College of American Pathologists-accredited and Clinical Laboratory Improvement Amendments-certified clinical laboratory, we quantified digital pathology features on 9,225 individual circulating tumor cells (CTC) from 179 unique metastatic castration-resistant prostate cancer (mCRPC) patients to define phenotypically distinct cell types. Heterogeneity was quantified on the basis of the diversity of cell types in individual patient samples using the Shannon index and associated with overall survival (OS) in the 145 specimens collected prior to initiation of the second or later lines of therapy. Low CTC phenotypic heterogeneity was associated with better OS in patients treated with androgen receptor signaling inhibitors (ARSI), whereas high heterogeneity was associated with better OS in patients treated with taxane chemotherapy. Overall, the results show that quantifying CTC phenotypic heterogeneity can help inform the choice between ARSI and taxanes in mCRPC patients. Cancer Res; 77(20); 5687-98. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Background: Fetal alcohol spectrum disorder, the leading known cause of mental retardation, is caused by alcohol exposure during pregnancy. One mechanism of ethanol (EtOH) teratogenicity is the disruption of the functions of L1 cell adhesion molecule (L1). These functions include enhancement of neurite outgrowth, trafficking through lipid rafts, and signal transduction. Recent data have shown that choline supplementation of rat pups reduces the effects of EtOH on neurobehavior. We sought to determine whether choline could prevent the effect of EtOH on L1 function using a simple experimental system., Methods: Cerebellar granule neurons (CGN) from postnatal day 6 rat pups were cultured with and without supplemental choline, and the effects on L1 signaling, lipid raft distribution, and neurite outgrowth were measured in the presence or absence of EtOH., Results: Choline significantly reduced the effect of EtOH on L1 signaling, the distribution of L1 in lipid rafts and L1-mediated neurite outgrowth. However, choline supplemented EtOH-exposed cultures remained significantly different than controls., Conclusions: Choline pretreatment of CGN significantly reduces the disruption of L1 function by EtOH, but does not completely return L1 function to baseline. This experimental system will enable discovery of the mechanism of the neuroprotective effect of choline., (Copyright © 2014 by the Research Society on Alcoholism.)

Background: Chlorhexidine is a skin disinfectant that reduces skin and mucous membrane bacterial colonization and inhibits organism growth. Despite numerous studies assessing chlorhexidine safety in term infants, residual concerns have limited its use in hospitalized neonates, especially low-birth-weight preterm infants. The aim of this study was to assess the potential neurotoxicity of chlorhexidine on the developing central nervous system using a well-established in vitro model of neurite outgrowth that includes laminin and L1 cell adhesion molecule (L1) as neurite outgrowth-promoting substrates., Methods: Cerebellar granule neurons are plated on poly L-lysine, L1, or laminin. Chlorhexidine, hexachlorophene, or their excipients are added to the media. Neurons are grown for 24 h, fixed, and neurite length is measured., Results: Chlorhexidine significantly reduced the length of neurites grown on L1 but not on laminin. Chlorhexidine concentrations as low as 125 ng/ml statistically significantly reduced neurite length on L1. Hexachlorophene did not affect neurite length., Conclusion: Chlorhexidine at concentrations detected in the blood following topical applications in preterm infants specifically inhibited L1-mediated neurite outgrowth of cerebellar granule neurons. It is now vital to determine whether the blood-brain barrier is permeable to chlorhexidine in preterm infants.

Each year the production of seasonal influenza vaccines requires antigen standards to be available for the potency assessment of vaccine batches. These are calibrated and assigned a value for haemagglutinin (HA) content. The calibration of an antigen standard is carried out in a collaborative study amongst a small number of national regulatory laboratories which are designated by WHO as Essential Regulatory Laboratories (ERLs) for the purposes of influenza vaccine standardisation. The calibration involves two steps; first the determination of HA protein in a primary liquid standard by measurement of total protein in a purified influenza virus preparation followed by determination of the proportion of HA as determined by PAGE analysis of the sample; and second, the calibration of the freeze-dried reference antigen against the primary standard by single radial immunodiffusion (SRD) assay. Here we describe a collaborative study to assess the effect of adding a deglycosylation step prior to the SDS-PAGE analysis for the assessment of relative HA content. We found that while the final agreed HA value of the samples tested was not significantly different with or without deglycosylation, the deglycosylation step greatly improved between-laboratory agreement., (Copyright © 2012 The International Alliance for Biological Standardization. All rights reserved.)

Acetyl-L-carnitine (ALCAR) is an endogenous metabolic intermediate that facilitates the influx and efflux of acetyl groups across the mitochondrial inner membrane. Exogenously administered ALCAR has been used as a nutritional supplement and also as an experimental drug with reported neuroprotective properties and effects on brain metabolism. The aim of this study was to determine oxidative metabolism of ALCAR in the immature rat forebrain. Metabolism was studied in 21-22 day-old rat brain at 15, 60 and 120 min after an intraperitoneal injection of [2-(13)C]acetyl-L-carnitine. The amount, pattern, and fractional enrichment of (13)C-labeled metabolites were determined by ex vivo(13)C-NMR spectroscopy. Metabolism of the acetyl moiety from [2-(13)C]ALCAR via the tricarboxylic acid cycle led to incorporation of label into the C4, C3 and C2 positions of glutamate (GLU), glutamine (GLN) and GABA. Labeling patterns indicated that [2-(13)C]ALCAR was metabolized by both neurons and glia; however, the percent enrichment was higher in GLN and GABA than in GLU, demonstrating high metabolism in astrocytes and GABAergic neurons. Incorporation of label into the C3 position of alanine, both C3 and C2 positions of lactate, and the C1 and C5 positions of glutamate and glutamine demonstrated that [2-(13)C]ALCAR was actively metabolized via the pyruvate recycling pathway. The enrichment of metabolites with (13)C from metabolism of ALCAR was highest in alanine C3 (11%) and lactate C3 (10%), with considerable enrichment in GABA C4 (8%), GLN C3 (approximately 4%) and GLN C5 (5%). Overall, our (13)C-NMR studies reveal that the acetyl moiety of ALCAR is metabolized for energy in both astrocytes and neurons and the label incorporated into the neurotransmitters glutamate and GABA. Cycling ratios showed prolonged cycling of carbon from the acetyl moiety of ALCAR in the tricarboxylic acid cycle. Labeling of compounds formed from metabolism of [2-(13)C]ALCAR via the pyruvate recycling pathway was higher than values reported for other precursors and may reflect high activity of this pathway in the developing brain. This is, to our knowledge, the first study to determine the extent and pathways of ALCAR metabolism for energy and neurotransmitter biosynthesis in the brain.

Background: The clinical presentation of pregnancy-associated malaria, or PAM, depends crucially on the particular epidemiological settings. This can potentially lead to an underestimation of its overall burden on the female population, especially in regions prone to epidemic outbreaks and where malaria transmission is generally low., Methods: Here, by re-examining historical data, it is demonstrated how excess female mortality can be used to evaluate the burden of PAM. A simple mathematical model is then developed to highlight the contrasting signatures of PAM within the endemicity spectrum and to show how PAM is influenced by the intensity and stability of transmission., Results: Both the data and the model show that maternal malaria has a huge impact on the female population. This is particularly pronounced in low-transmission settings during epidemic outbreaks where excess female mortality/morbidity can by far exceed that of a similar endemic setting., Conclusion: The results presented here call for active intervention measures not only in highly endemic regions but also, or in particular, in areas where malaria transmission is low and seasonal.

The enzyme aspartate aminotransferase (AAT) has a number of key roles in astrocytes and neurons in brain. An understanding of the regulation of AAT is important since AAT is involved in many aspects of glutamate metabolism including the synthesis of neurotransmitter glutamate. Mitochondrial AAT binds to a protein and lipids on the inner mitochondrial membrane and also forms a number of transient hetero-enzyme complexes with other enzymes. These complexes serve to facilitate metabolism by essentially channeling substrates and cofactors to other enzymes within the complex. The association and dissociation of transiently formed hetero-enzyme complexes may modulate enzyme activity in "real time" since these complexes are dynamically influenced by changes in the concentration of a number of key metabolites. The influence of several effectors that modulate AAT activity, either directly, or by altering the binding of AAT to mitochondrial lipids, or the association/dissociation into transient hetero-enzyme complexes was determined. The addition of palmitate, malate, citrate, glutamate, bovine serum albumin and Mg(2+) modulated AAT activity differently in synaptic and nonsynaptic mitochondria from brain. These findings suggest that AAT activity and also glutamate metabolism, may be regulated in part, by metabolites that influence binding of the enzyme to lipids or proteins in the inner mitochondrial membrane and/or the association/dissociation of transient hetero-enzyme complexes. This may have a role in the compartmentation of glutamate metabolism in brain.

Nasal potential difference (NPD) has served as a non-invasive diagnostic method for cystic fibrosis (CF) a disease of chloride channel expression and function in secretory epithelia. Investigators have also used NPD to demonstrate ion transport abnormalities in newborns with respiratory distress. Standard perfusates for diagnostic NPD studies include the use of amiloride, replacement of chloride with gluconate, cAMP agonists, and nucleotides such as ATP. The pH of these perfusates may also be relevant to NPD studies as we have previously shown that the respiratory epithelia in mammals express CLC-2, which is a pH sensitive chloride channel. We hypothesized that acidic pH might activate chloride secretion in vivo if CLC-2 is present in human respiratory epithelia. Our objective was to determine the effect of acidic pH on NPD measurements and the frequency of expression of CLC-2 in normal subjects. Healthy adults were recruited and CLC-2 protein expression was detected in 20 of 29 primary nasal epithelial cell cultures. Acidic pH stimulated NPD responses in 33% of subjects. These findings suggest that pH sensitive alternative pathways are available for modulation in human respiratory epithelia and that NPD protocols should standardize pH of perfusates., (2006; 41:151-157. (c) 2005 Wiley-Liss, Inc.)

Epithelial Cl(-) channels mediate Cl(-) and fluid secretion in the lung. In cystic fibrosis, aberrant Cl(-) secretion is one of the major causes for lung fluid imbalance. Regulation of Cl(-) channels is therefore an important issue in the lung. IFN-gamma regulates Na(+) and Cl(-) channels and fluid transport in the lung, but the mechanisms involved in these regulations are not clear. In expression studies, we found that IFN-gamma increased ClC-2 transcripts in Calu-3 cells. Studies of the promoter identified a minimal promoter which interacts with transcription factors Sp1 and Sp3. However, reporter gene assays showed that IFN-gamma did not activate the promoter. Instead, IFN-gamma significantly increased ClC-2 transcript stability. Using Ussing chamber experiments, we demonstrate that IFN-gamma activates a pH-regulated and Cd(2+)-sensitive short circuit current, characteristic properties of the ClC-2 Cl(-) channel. These data suggest that IFN-gamma activates ClC-2 channel activity in lung epithelial cells via mRNA stabilization.

Background: Cystic fibrosis (CF) lung disease manifest by impaired chloride secretion leads to eventual respiratory failure. Candidate genes that may modify CF lung disease severity include alternative chloride channels. The objectives of this study are to identify single nucleotide polymorphisms (SNPs) in the airway epithelial chloride channel, CLC-2, and correlate these polymorphisms with CF lung disease., Methods: The CLC-2 promoter, intron 1 and exon 20 were examined for SNPs in adult CF dF508/dF508 homozygotes with mild and severe lung disease (forced expiratory volume at one second (FEV1) > 70% and < 40%)., Results: PCR amplification of genomic CLC-2 and sequence analysis revealed 1 polymorphism in the hClC -2 promoter, 4 in intron 1, and none in exon 20. Fisher's analysis within this data set, did not demonstrate a significant relationship between the severity of lung disease and SNPs in the CLC-2 gene., Conclusions: CLC-2 is not a key modifier gene of CF lung phenotype. Further studies evaluating other phenotypes associated with CF may be useful in the future to assess the ability of CLC-2 to modify CF disease severity.

Normal lung morphogenesis is dependent on chloride-driven fluid transport. The molecular identity of essential fetal lung chloride channel(s) has not been elucidated. CLC-2 is a chloride channel, which is expressed on the apical surface of the developing respiratory epithelium. CLC-2-like pH-dependent chloride secretion exists in fetal airway cells. We used a 14-day fetal rat lung submersion culture model to examine the role of CLC-2 in lung development. In this model, the excised fetal lung continues to grow, secrete fluid, and become progressively cystic in morphology (26). We inhibited CLC-2 expression in these explants, using antisense oligonucleotides, and found that lung cyst morphology was disrupted. In addition, transepithelial voltage (V(t)) of lung explants transfected with antisense CLC-2 was inhibited with V(t) = -1.5 +/- 0.2 mV (means + SE) compared with -3.7 +/- 0.3 mV (means + SE) for mock-transfected controls and -3.3 +/- 0.3 mV (means + SE) for nonsense oligodeoxynucleotide-transfected controls. This suggests that CLC-2 is important for fetal lung fluid production and that it may play a role in normal lung morphogenesis.

Background & Aims: Enteric infections have been implicated in the pathogenesis of both food intolerance and autoimmune diseases secondary to the impairment of the intestinal barrier. On the basis of our recent discovery of zonulin, a modulator of small-intestinal tight junctions, we asked whether microorganisms might induce zonulin secretion and increased small-intestinal permeability., Methods: Both ex vivo mammalian small intestines and intestinal cell monolayers were exposed to either pathogenic or nonpathogenic enterobacteria. Zonulin production and changes in paracellular permeability were monitored in Ussing chambers and micro-snapwells. Zonula occludens 1 protein redistribution after bacteria colonization was evaluated on cell monolayers., Results: Small intestines exposed to enteric bacteria secreted zonulin. This secretion was independent of either the species of the small intestines or the virulence of the microorganisms tested, occurred only on the luminal aspect of the bacteria-exposed small-intestinal mucosa, and was followed by a decrease in small-intestinal tissue resistance (transepithelial electrical resistance). The transepithelial electrical resistance decrement was secondary to the zonulin-induced tight junction disassembly, as also shown by the disengagement of the protein zonula occludens 1 protein from the tight junctional complex., Conclusions: This zonulin-driven opening of the paracellular pathway may represent a defensive mechanism, which flushes out microorganisms and contributes to the host response against bacterial colonization of the small intestine.

The mentoring connections that we have experienced in our school of nursing have eased difficult situations and have promoted self-awareness, personal and professional growth, and leadership behaviors. Various circumstances result in behaviors reflective of issues of culture, race, self-esteem and knowledge, values, ethics, experience, and conflict management. Some of these issues are related to oppressed group behavior, inadequate communication and conflict resolution skills, lack of exposure to diverse academic and professional experiences, and a need to learn management of feelings in effective ways. As faculty, administrators, students, and alumni, we struggle with those issues, knowing that resolution of them is beyond the traditional modes of teaching-learning, academic relationships and professional socialization. We wish that we and our students and alumni will experience an increased connectedness to the school and profession. We also wish that we might, as a result of our mentor connections, individually and collectively develop self-determination, self-esteem and confidence, leadership skills, and inner directness. The Mentor Connection Program was initiated in response to these strong wishes and has been a motivating framework for the reciprocal growth in us all. As for the future, we will continue our research and evaluation studies, refine the matching criteria, support and expand the mentoring dyads, strengthen faculty-faculty mentoring relationships, and seek funding resources for expansion and research. We are seeing the positive effects of active mentoring on students, faculty, and alumni on issues related to teaching and learning, support, hardiness, and self-reflection. Mentors produce leaders. Nursing's collective leadership will, we believe, depend to a large extent on our mentoring relationships with each other.

Background: L-Glutamine is the principal energy source for small intestinal enterocytes. Diminution of intestinal function, mucosal atrophy, and increased bacterial translocation have been noted during total parenteral nutrition (TPN). In a rat model of glutamine starvation, we previously showed that luminal glutamine is essential for optimal intestinal function. In this study, we examined the effect of apical vs basolateral glutamine on bacterial translocation in a Caco-2 cell culture system and bacteria-induced tissue injury in a weanling rabbit ileal loop model., Methods: Caco-2 cells were grown in a transwell system. After confluence, apical and basolateral chambers received defined media, and glutamine deprivation was carried out over a 4- to 48-hour period. Escherichia coli transcytosis and structure/function studies were then performed. In a second series of experiments, the effect of intraluminal glutamine supplementation was evaluated in an E. coli-induced tissue injury model in weanling rabbit ileal loops., Results: Expression of disaccharidases, glucoamylase, and Na+/K(+)-adenosine 5'-triphosphatase (ATPase) were significantly reduced when cells were deprived of glutamine from the apical side, and there was increased bacterial translocation across the monolayer. Transepithelial epithelial resistance (TEER) across the monolayer was also reduced in the glutamine-free cultures. Glutamine replenishment over 24 to 48 hours restored the original functions. Basolateral deprivation had a smaller effect on the Caco-2 cells. Typical necrotic mucosal injury caused by E. coli in the ileal loops was blocked by co-infiltration of the loops with glutamine., Conclusions: This study demonstrates for the first time that the supply of glutamine from the apical side is of critical importance for maintaining optimal structure and function of the enterocytes. The effects are not acute or energy related. These observations have important clinical implications in the management of patients under critical care, including premature infants and patients receiving TPN, for whom lack of glutamine from the luminal side could produce mucosal dysfunction, resulting ultimately in severe atrophic/necrotic complications.

Necrotizing enterocolitis (NEC) is a serious gastrointestinal disorder of preterm infants. Other than an association with prematurity and gastrointestinal feeding, no single factor or mechanism has been consistently linked to this disease. We have previously demonstrated that Escherichia coli isolates obtained from the stool of infants with NEC caused NEC-like injury in a weanling rabbit ileal loop model; this injury, in turn, could be blocked by coinfection with selected Gram(+) bacteria (Enterococcus faecium) isolated from asymptomatic controls. Using Caco-2 cells in a trans-well system, we now demonstrate that the same E. coli isolates can cross epithelial cell monolayers in the absence of ultrastructural change or damage. These results with E. coli contrast with those seen with Salmonella typhimurium, which passed through the monolayer at a higher rate and were associated with striking ultrastructural damage. Transcytosis of E. coli was reduced 3-5-fold in the presence of E. faecium previously shown to block NEC-like injury in the loop model. There was a mild increase in the rate of E. coli transcytosis when studies were conducted with younger, undifferentiated cells; these immature cells had no brush border, had decreased production of brush border-specific enzymes, but retained well defined tight junctions, as demonstrated by transepithelial electrical resistance and electron microscopy. A further reduction/ complete blockage of E. coli transcytosis was observed when E. faecium was used as the coinfectant in studies with these undifferentiated cells. We hypothesize that the ability of E. coli to cross epithelial cell layer is a critical initial step in the cascade of events which lead ultimately to NEC; blockage or reduction in E. coli transcytosis in the presence of certain Gram(+) organisms may play a significant role in prevention of NEC.

Neoplastic and nonneoplastic tissue from human uterine cervixes was stained immunohistochemically for three epithelial antigens--epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and cytoplasmic keratin. Anti-EMA serum stained four of 21 nonneoplastic cases and all cases of cervical intraepithelial neoplasia (CIN) (25) and invasive carcinoma (16); CEA was positive in six of ten of the nonneoplastic specimens, 19 of 23 CIN specimens, and six of seven invasive carcinomas tested. Cytoplasmic keratin did not survive fixation in formal saline and for this antigen tissue had to be fixed in methacarn; all the tissues examined were positive.

The smears preceding the histologic diagnosis of cervical intraepithelial neoplasia (CIN 3) were examined in 100 consecutive cases from an intensively screened population. In 60 patients, negative cytology has been recorded prior to the development of dysplasia; in 27 this had occurred within two years of the histologic diagnosis. These findings suggest that the transition time from epithelial normality to CIN 3 may be shorter than has been generally assumed; therefore, the intensity and frequency of screening should be reviewed.