Structure- and machine learning-guided engineering demonstrate that a non-canonical disulfide in an anti-PD-1 rabbit antibody does not impede antibody developability

Rabbits produce robust antibody responses and have unique features in their antibody repertoire that make them an attractive alternative to rodents for in vivo discovery. However, the frequent occurrence of a non-canonical disulfide bond between complementarity-determining region (CDR) H1 (C35a) and CDRH2 (C50) is often seen as a liability for therapeutic antibody development, despite limited reports of its effect on antibody binding, function, and stability. Here, we describe the discovery and humanization of a human-mouse cross-reactive anti-programmed cell death 1 (PD-1) monoclonal rabbit antibody, termed h1340.CC, which possesses this non-canonical disulfide bond. Initial removal of the non-canonical disulfide resulted in a loss of PD-1 affinity and cross-reactivity, which led us to explore protein engineering approaches to recover these. First, guided by the sequence of a related clone and the crystal structure of h1340.CC in complex with PD-1, we generated variant h1340.SA.LV with a potency and cross-reactivity similar to h1340.CC, but only partially recovered affinity. Side-by-side developability assessment of both h1340.CC and h1340.SA.LV indicate that they possess similar, favorable properties. Next, and prompted by recent developments in machine learning (ML)-guided protein engineering, we used an unbiased ML- and structure-guided approach to rapidly and efficiently generate a different variant with recovered affinity. Our case study thus indicates that, while the non-canonical inter-CDR disulfide bond found in rabbit antibodies does not necessarily constitute an obstacle to therapeutic antibody development, combining structure- and ML-guided approaches can provide a fast and efficient way to improve antibody properties and remove potential liabilities.

Translatability of In Vitro Stress for Predicting Deamidation and Oxidation Biotransformation on Biotherapeutics

Biotransformation leading to single residue modifications (e.g., deamidation, oxidation) can contribute to decreased efficacy/potency, poor pharmacokinetics, and/or toxicity/immunogenicity for protein therapeutics. Identifying and characterizing such liabilities in vivo are emerging needs for biologics drug discovery. In vitro stress assays involving PBS for deamidation or AAPH for oxidation are commonly used for predicting liabilities in manufacturing and storage and are sometimes considered a predictive tool for in vivo liabilities. However, reports discussing their in vivo translatability are limited. Herein, we introduce a mass spectrometry workflow that characterizes in vivo oxidation and deamidation in pharmacokinetically relevant compartments for diverse protein therapeutic modalities. The workflow has low bias of <10% in quantitating degradation in the relevant pharmacokinetic concentration range for monkey and rabbit serum/plasma (1-100 μg/mL) and allows for high sequence coverage (∼85%) for discovery/monitoring of amino acid modifications. For oxidation and deamidation, the assay was precise, with percent coefficient of variation of <8% at 1-100 μg/mL and ≤6% method-induced artifacts. A high degree of in vitro and in vivo correlation was observed for deamidation on the six diverse protein therapeutics (seven liability sites) tested. In vivo translatability for oxidation liabilities were not observed for the 11 molecules tested using in vitro AAPH stress. One of the molecules dosed in eyes resulted in a false positive and a false negative prediction for in vivo oxidation following AAPH stress. Finally, peroxide stress was also tested but resulted in limited success (1 out of 4 molecules) in predicting oxidation liabilities.

The effects of heparin, aspirin, and maternal clinical factors on the rate of nonreportable cell-free DNA results: a retrospective cohort study

BACKGROUND

Technological advances in the analysis of cell-free DNA in maternal serum have allowed expanded prenatal screening possibilities for fetal aneuploidies. The sensitivity and positive predictive value of the assay are partly dependent on the amount of cell-free DNA present in maternal circulation. Thus, it is important to know what fetal and maternal factors influence the level of cell-free DNA in maternal circulation. Maternal heparin use has been associated with an increase in nonreportable cell-free DNA results because of a low fetal fraction in some, but not all, previous studies. In addition, there are likely additional factors that affect cell-free DNA that remain uncharacterized.

OBJECTIVE

This study aimed to determine whether heparins, low-dose aspirin, and maternal clinical factors affect the rate of nonreportable cell-free DNA testing results.

STUDY DESIGN

A retrospective cohort study was conducted using pregnant people receiving cell-free fetal DNA testing from January 1, 2014, to June 30, 2018. Data were collected on patient demographics, medical comorbidities, medication use, and cell-free DNA test results. Univariate and multivariate analyses were performed to determine which factors were independently associated with the rate of nonreportable results.

RESULTS

From an original sample of 1117 pregnant people, 743 met the inclusion criteria. Maternal weight (odds ratio, 1.02), heparin use (odds ratio, 12.06), aspirin use (odds ratio, 4.70), chronic hypertension (odds ratio, 5.26), pregestational diabetes mellitus (odds ratio, 2.46), and autoimmune disease (odds ratio, 3.59) were significantly associated with an increased rate of nonreportable results in the univariate analysis. Moreover, the association was present for maternal weight (odds ratio, 1.02), heparin use (odds ratio, 21.87),and aspirin use (odds ratio, 2.85) in the multivariate analysis.

CONCLUSION

The previously seen association between maternal heparin use and an increase in nonreportable cell-free DNA results was confirmed. Furthermore, there seems to be an increase in nonreportable results in pregnant people taking low-dose aspirin. Providers should consider the effect of these medications when counseling patients on prenatal genetic screening options.

Endoscopic Botulinum toxin as a treatment for delayed gastric emptying following oesophagogastrectomy

INTRODUCTION

The incidence of delayed gastric emptying (DGE) following oesophagogastrectomy with gastric conduit reconstruction is reported to be between 1.7% and 50%. This variation is due to differing practices of intraoperative pylorus drainage procedures, which increase the risk of postoperative biliary reflux and dumping syndrome, resulting in significant morbidity. The aim of our study was to establish rates of DGE in people undergoing oesophagogastrectomy without routine intraoperative drainage procedures, and to evaluate outcomes of postoperative endoscopically administered Botulinum toxin into the pylorus (EBP) for people with DGE resistant to systemic pharmacological treatment.

METHODS

All patients undergoing oesophagogastrectomy between 1 January 2016 and 31 March 2018 at our unit were included. No intraoperative pyloric drainage procedures were performed, and DGE resistant to systemic pharmacotherapy was managed with EBP.

RESULTS

Ninety-seven patients were included. Postoperatively, 29 patients (30%) were diagnosed with DGE resistant to pharmacotherapy. Of these, 16 (16.5%) were diagnosed within 30 days of surgery. The median pre-procedure nasogastric tube aspirate was 780ml; following EBP, this fell to 125ml (p<0.001). Median delay from surgery to EBP in this cohort was 13 days (IQR 7-16 days). Six patients required a second course of EBP, with 100% successful resolution of DGE before discharge. There were no procedural complications.

CONCLUSIONS

This is the largest series of patients without routine intraoperative drainage procedures. Only 30% of patients developed DGE resistant to pharmacotherapy, which was managed safely with EBP in the postoperative period, thus minimising the risk of biliary reflux in people who would otherwise be at risk following prophylactic pylorus drainage procedures.

Skin barrier lipid enzyme activity in Netherton patients is associated with protease activity and ceramide abnormalities

Individuals with Netherton syndrome (NTS) have increased serine protease activity, which strongly impacts the barrier function of the skin epidermis and leads to skin inflammation. Here, we investigated how serine protease activity in NTS correlates with changes in the stratum corneum (SC) ceramides, which are crucial components of the skin barrier. We examined two key enzymes involved in epidermal ceramide biosynthesis, β-glucocerebrosidase (GBA) and acid-sphingomyelinase (ASM). We compared in situ expression levels and activities of GBA and ASM between NTS patients and controls and correlated the expression and activities with i) SC ceramide profiles, ii) in situ serine protease activity, and iii) clinical presentation of patients. Using activity-based probe labeling, we visualized and localized active epidermal GBA, and a newly developed in situ zymography method enabled us to visualize and localize active ASM. Reduction in active GBA in NTS patients coincided with increased ASM activity, particularly in areas with increased serine protease activity. NTS patients with scaly erythroderma exhibited more pronounced anomalies in GBA and ASM activities than patients with ichthyosis linearis circumflexa. They also displayed a stronger increase in SC ceramides processed via ASM. We conclude that changes in the localization of active GBA and ASM correlate with i) altered SC ceramide composition in NTS patients, ii) local serine protease activity, and iii) the clinical manifestation of NTS.

Cryptococcosis in pregnancy and the postpartum period: Case series and systematic review with recommendations for management

Cryptococcal meningitis causes 15% of AIDS-related deaths. Optimal management and clinical outcomes of pregnant women with cryptococcosis are limited to case reports, as pregnant women are often excluded from research. Amongst pregnant women with asymptomatic cryptococcosis, no treatment guidelines exist. We prospectively identified HIV-infected women who were pregnant or recently pregnant with cryptococcosis, screened during a series of meningitis research studies in Uganda from 2012 to 2018. Among 571 women screened for cryptococcosis, 13 were pregnant, one was breastfeeding, three were within 14 days postpartum, and two had recently miscarried. Of these 19 women (3.3%), 12 had cryptococcal meningitis, six had cryptococcal antigenemia, and one had a history of cryptococcal meningitis and was receiving secondary prophylaxis. All women with meningitis received amphotericin B deoxycholate (0.7-1.0 mg/kg). Five were exposed to 200-800 mg fluconazole during pregnancy. Of these five, three delivered healthy babies with no gross physical abnormalities at birth, one succumbed to meningitis, and one outcome was unknown. Maternal meningitis survival rate at hospital discharge was 75% (9/12), and neonatal/fetal survival rate was 44% (4/9) for those mothers who survived. Miscarriages and stillbirths were common (n = 4). Of six women with cryptococcal antigenemia, two received fluconazole, one received weekly amphotericin B, and three had unknown treatment courses. All women with antigenemia survived, and none developed clinical meningitis. We report good maternal outcomes but poor fetal outcomes for cryptococcal meningitis using amphotericin B, without fluconazole in the first trimester, and weekly amphotericin B in place of fluconazole for cryptococcal antigenemia.

Physiological Characteristics of Musical Theatre Performers and the Effect on Cardiorespiratory Demand Whilst Singing and Dancing

AIMS

Musical theatre (MT) combines acting, singing, and dancing within a performance. The purpose of the current study was two-fold: 1) to report on the cardiorespiratory fitness of pre-professional MT dancers, and 2) to examine the cardiorespiratory demand of singing whilst dancing.

METHODS

Twenty-one participants (16 females, 5 males; age 20±1.23 yrs; height 169.1±9.24 cm; weight 62.7±10.56) in their final year of pre-professional training volunteered for the study. All participants performed a maximal aerobic capacity test on a treadmill using a portable breath-by-breath gas analyser. Nine participants completed a 4-minute section from Chorus Line twice, singing and dancing and just dancing, in a randomised order whilst wearing the same portable gas analyser. Blood lactate was measured at the end of each trial.

RESULTS

Male participants had significantly greater peak oxygen consumption (M vs F, 67.6±2.30 vs 55.6±4.42 mL/kg/min, p<0.001) and anaerobic threshold (% of peak VO2) (54.6±4.04% vs 43.1±3.68%, p<0.001), whilst maximum heart rate and heart rate at anaerobic threshold were similar. The physiological demands of dancing vs singing + dancing were similar, with the exception of the singing + dancing trial having significantly reduced mean breathing frequency and increased lactate (p<0.01).

CONCLUSIONS

MT dancers' aerobic capacity is greater than that observed in other theatre-based dance genres. The observed breathing frequency and lactate differences in the Chorus Line trails could be due to singing reducing breathing frequency, thereby influencing cardiorespiratory recovery mechanics and subsequently blood lactate levels.

First case of a dog infected with Aspergillus (Phialosimplex) caninus in Australasia

Case history: A 2-year-old Rottweiler dog from Perth (WA, Australia) was referred for assessment of a chronic productive cough and weight loss.Clinical findings: Severely enlarged bilateral superficial cervical lymph nodes and severely enlarged abdominal organs were present. The body condition score was poor and there was moderate muscle wasting. Thoracic and abdominal computed tomography images revealed severe diffuse enlargement of thoracic and abdominal lymph nodes, hepatomegaly and diffuse splenomegaly. A diffuse bronchial pattern with severe multifocal saccular bronchiectasis was identified in the lungs.Diagnostic findings: Fungal organisms were seen within macrophages on cytological preparations and on histopathological sections of biopsies of the superficial cervical lymph node. Macrophages contained intracytoplasmic, non-filamentous round-to-ovoid organisms, which varied in size from 5-30 µm in diameter with variable morphology. Budding was not observed, and no hyphae were present. Fungal culture of lymph node tissue resulted in growth of Aspergillus (Phialosimplex) caninus which was confirmed by amplification and sequencing of a segment of the 16S-23S rRNA internal transcribed spacer. Concurrent bacterial bronchitis was diagnosed on culture of broncho-alveolar fluid.Diagnosis: Disseminated aspergillosis caused by Aspergillus caninus.Clinical relevance: This is believed to be the first report of infection caused by A. caninus in a dog in Australasia. The dog was treated with itraconazole for 7 months and was still alive 7 months after the start of treatment.

Cerebral Oximetry for Detecting High-mortality Risk Patients with Cryptococcal Meningitis

Background

Cryptococcus is the commonest cause of adult meningitis in Africa, with 50%–70% experiencing increased intracranial pressure. Cerebral oximetry is a noninvasive near-infrared spectroscopy technology to monitor percent regional cerebral tissue oxygenation (rSO₂). We assessed if cerebral oximetry predicts meningitis mortality.

Methods

We performed cerebral oximetry within 14 days of cryptococcal meningitis diagnosis on 121 Ugandans from April 2016 to September 2017. We evaluated baseline rSO₂ association with mortality by multivariable logistic regression and correlation with other clinical factors. We compared groups formed by initial rSO₂ <30% vs ≥30% for longitudinal change with mixed effects models. We measured change in %rSO₂ before and after lumbar puncture (LP).

Results

The median initial rSO₂ (interquartile range) was 36% (29%–42%), and it was <30% in 29% (35/121). For 30-day mortality, the unadjusted odds ratio (per 5% increase in rSO₂) was 0.73 (95% confidence interval [CI], 0.58 to 0.91; P = .005). Those with initial rSO₂ <30% had 3.4 (95% CI, 1.5 to 8.0) higher odds of 30-day mortality than those with initial rSO₂ ≥30%. Hemoglobin correlated with initial rSO₂ (rho = .54; P < .001), but rSO₂ did not correlate with pulse oximetry, intracranial pressure, cerebral perfusion pressure, or quantitative cerebrospinal fluid culture, and rSO₂ was unchanged pre/post–lumbar punctures. The longitudinal rSO₂ measurements change was 15% (95% CI, 12% to 18%) lower in the group with initial rSO₂ <30%.

Conclusions

Individuals with cryptococcal meningitis and low cerebral oximetry (rSO₂ < 30%) have high mortality. Cerebral oximetry may be useful as a prognostic marker of mortality. Targeted interventions to improve rSO₂ should be tested in trials to try to decrease mortality in meningitis.

New tele-diagnostic model using volume sweep imaging for rural areas

Advances in information and communications technologies provide a new opportunity to improve the access to healthcare in remote rural areas (RA) where there is a lack of infrastructure and medical experts. This paper implements a new model for tele-ultrasound (US) based on volumetric sweep imaging protocols specially designed for the acquisition of US. Non-physician health personnel from the RA are trained on the use of these protocols in a few days. The operator utilizes the medical box (MB), a specially designed telecommunication system, to guide, compress, encrypt and transmit the US sweeps through the cloud to the radiologist who performs the diagnosis remotely. The report is automatically sent back to the MB. The system was able to send US volumetric images with poor connectivity conditions in 6 minutes on average. These results of implementing this tele-ultrasound model in RAs are encouraging and support future validations.

Animal and human health is unlikely to be at risk when generations of sheep graze bauxite residue (Alkaloam®)-amended pastures

Bauxite residue (Alkaloam®) applied to pasture has been shown significantly to improve pasture production on sub-fertile soil, such as those found in south-west Western Australia, because it increases soil pH. There are concerns that animals grazing Alkaloam-amended pasture may suffer ill health through heavy metal accumulation in tissues, and that this effect could be amplified over generations. There are additional concerns that eating exposed animals, or direct exposure to Alkaloam, may be detrimental to human health. Although some literature exists there are no studies that address these issues when the application of Alkaloam occurred several years (20) before grazing. This investigation examined the heavy metal and trace element accumulation in the tissues of Dorper lambs (1 year old) and their dams, Dorper ewes (4–5 years old) grazing Alkaloam-amended pasture. The experiment was conducted on two sites grazed in the Peel region of Western Australia: one site in Coolup, the Control site (Site C), that had had no application of Alkaloam and one site in Wagerup, the Treatment site (Site T), that had had 20 tonnes per hectare of Alkaloam applied in 1993. Both sites had uniform soil and pasture type during the growing season. Samples of soil and pasture were collected at each site. Differences in trace element concentrations, pH and conductivity between sites were determined. Ten ewes and 10 lambs were randomly selected at each site, removed and killed on the same day for gross examination of the kidney, liver and lung tissue. Samples of the tissues were collected for histopathological examination and chemical analysis to determine concentrations of trace elements. Depending on the concentration of trace elements in each sample, a logistical regression with binomial regression or an ANOVA was performed to determine differences in concentrations between ages, sites and any interactions between age and site. Sheep from Site T had significantly higher concentrations of copper, manganese and molybdenum, whereas sheep from Site C had significantly higher concentrations of cobalt, iron, lead, nickel, selenium, strontium and zinc in tissues. Ewes had significantly higher concentrations of barium, cadmium, cobalt, iron and strontium whereas lambs had significantly higher concentrations of copper, manganese and molybdenum in tissues. Ewes had higher concentrations of cadmium in the kidney compared with lambs, and ewes from Site C had significantly higher concentrations than ewes from Site T. Ewes and lambs from Site C had significantly higher concentrations of selenium in the liver compared with ewes and lambs from Site T. Concentrations of heavy metals (As, Hg, Pb, Th and U) were low in tissues of all sheep. The results show that whereas there were different elemental tissue concentrations between sites and between ages of sheep, there were no detrimental trace element imbalances or accumulation of heavy metals that would cause ill health in any of the sheep that could be associated with the application of Alkaloam to pasture. It is unlikely that humans will suffer any ill effects as a consequence of eating exposed animals. This result supports the premise that bauxite residue can be safely applied to pasture to significantly improve pasture and animal production where animals graze pasture growing on sub-fertile soil.

Alemtuzumab in T-cell large granular lymphocytic leukaemia: interim results from a single-arm, open-label, phase 2 study

Background

T-cell large granular lymphocytic leukemia (T-LGL) is a lymphoproliferative disease presenting with immune-mediated cytopenias and characterized by clonal expansion of cytotoxic CD3⁺CD8⁺ lymphocytes. Methotrexate, cyclosporine, or cyclophosphamide improve cytopenias in 50% of patients as first therapy, but the activity of an anti-CD52 monoclonal antibody, alemtuzumab, is not defined in T-LGL.

Methods

Twenty-five consecutive subjects with T-LGL were enrolled from October 2006 to March 2015 at the National Institutes of Health (www.clinicaltrials.gov-NCT00345345). Alemtuzumab was administered at 10 mg/day intravenously for 10 days. The primary endpoint was haematologic response at 3 months. Analysis was intention to treat. Here we report the protocol specified interim benchmark of a phase II clinical trial using alemtuzumab in T-LGL.

Findings

In this heterogeneous, previously treated cohort, 14/25 (56%; 95% CI, 37–73%) subjects had a haematological response at 3 months. In T-LGL cases not associated with myelodysplasia or marrow transplantation, the response rate was 14/19 (74%; 95% CI, 51–86%). First dose infusion reactions were common which improved with symptomatic therapy. EBV and CMV reactivations were common and subclinical. In only 2 patients pre-emptive anti-CMV therapy was instituted. There were no cases of EBV or CMV disease. Alemtuzumab induced sustained reduction of absolute clonal population of T-cytotoxic lymphocytes, as identified by TCRBV-receptor phenotype, but the abnormal clone serendipitously persisted in responders. STAT3 mutations in the SH2 domain, identified in ten subjects, did not correlate with response. When compared with healthy volunteers, T-LGL subjects showed a distinct plasma cytokine and JAK-STAT signature prior to treatment, but neither correlated to response.

Interpretation

This is the largest and only prospective cohort of T-LGL subjects treated with alemtuzumab yet reported. The high activity with a single course of a lymphocytotoxic agent in a mainly relapsed and refractory suggests that haematologic response outcomes can be accomplished without the need for continued use of oral immunosuppression.

Funding

This research was supported by the Intramural Research Program of the NIH, National Heart, Lung, and Blood Institute.

WITHDRAWN: Corrigendum to "The pathology and pathogenicity of a novel Haemoproteus spp. infection in wild Little Penguins (Eudyptula minor)" [Vet. Parasitol. 197 (1-2) (2013) 74-84]

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.vetpar.2014.07.021. The duplicate article has therefore been withdrawn.

An unidentified lipid prevalent in tumors

An unidentified lipid was found in five different tumor sources. It was not found in liver, bone marrow or plasma from tumor-bearing animals, nor in the extracellular fluid supporting growth of Ehrlich ascites cells. The polarity of the unidentified component was similar to that of a glyceryl ether diester, and it was isolated in milligram amounts by preparative thinlayer chromatography. Neither methyl esters of fatty acids, vinyl ether diesters nor quinones were found in the structural makeup of this lipid. Thin-layer chromatography of the purified unidentified tumor lipid on Ag-impregnated silica layers revealed two main components of intermediary unsaturation. Saponification of the unidentified tumor lipid, when water washing was omitted, yielded two components that migrated at R(f)'s identical to those of free fatty acids and dihydroxy glyceryl monoethers. Neither acetate-1-(14)C nor palmitic-1-(14)C acid (single injections) was found to be incorporated into the unidentified lipid of a mature rat tumor.

Rituximab administration within 6 months of T cell-depleted allogeneic SCT is associated with prolonged life-threatening cytopenias

The monoclonal anti-CD20 antibody Rituximab (RTX) is increasingly used in allogeneic stem cell transplantation (SCT) to treat lymphoproliferative disorders and chronic graft-versus-host disease (GVHD). RTX administration can be complicated by delayed and prolonged neutropenia, but the mechanism is unclear. We report the occurrence of profound cytopenias following RTX given in the conditioning regimen or early after T cell-deplete SCT to treat B cell lymphoproliferative disorders or chronic GVHD (cGVHD). Between 2006 and 2009, 102 patients (median age: 43 years, range: 13-68 years), received a myeloablative matched-sibling T cell-deplete SCT for lymphoid or myeloid hematologic disorders. Neutropenia occurring within 4 weeks of treatment developed in 16 of 17 patients given RTX within the first 190 days after SCT. Fourteen patients developed severe neutropenia (count <0.5 K/μL) lasting up to 10 months and 12 required hospitalization to treat severe neutropenic infections. Six of the 14 patients died of infection complicating GVHD treatment. Recovery of lymphocytes and immunoglobulins was also delayed, with a significantly lower absolute lymphocyte counts (ALC) at 9 months and 12 months post-SCT compared to patients with cGVHD not treated with early RTX (P < .02). In contrast, patients receiving RTX 1 year after SCT experienced only moderate neutropenia 3 to 5 months after treatment lasting 10 to 20 days while maintaining absolute neutrophil count (ANC) >1.0 × 10⁹/L. Although RTX rapidly controlled cGVHD, we conclude that its administration early after T cell-deplete SCT is associated with prolonged profound and life-threatening cytopenias, and should be avoided.

MRI demonstrates the extension of juxta-articular venous malformation of the knee and correlates with joint changes

OBJECTIVE

Juxta-articular venous malformations (VMs) are uncommon, but may cause early arthropathy of the knee in children and adolescents. We sought to describe the prevalence, extent and initial magnetic resonance imaging (MRI) features of knee arthropathy in children with VM adjacent to the knee joint.

METHODS

Thirty-five patients with VM adjacent to the knee who had MRI performed between 2000 and 2009 were identified through a keyword search of the radiology information system.

RESULTS

VM extended to the joint in 17 of the 35 patients (5.4-21.5 years, mean 11.8 years). Most of these 17 patients had joint changes (15/17, 88%), most commonly haemosiderin deposition (14/17, 82%). Other findings included the presence of subchondral bone lesions (eight, 47%), cartilage loss (six, 35%), synovial thickening (six, 35%), marrow oedema (six, 35%), joint effusion (five, 29%), subchondral cysts (five, 29%) and one loose body (6%). VM location and size did not correlate with the degree of articular involvement. Joint changes were present in focal as well as non-discrete VM.

CONCLUSION

We found that the frequency of arthropathy increased with extension of VM into the joint itself. This finding stresses the importance of early MRI evaluation of all juxta-articular VM.

Treat the patient not the blood test: the implications of an increase in cardiac troponin after prolonged endurance exercise

Collapse after prolonged endurance exercise is common and usually benign. This case study reports a triathlete who suffered a vaso-vagal associated collapsed after exercise. Misdiagnosis of myocardial injury in the presence of elevated cardiac troponins and ECG anomalies led to inappropriate management and highlights the difficulty in treating the collapsed athlete following arduous exercise.

Spontaneous atrial fibrillation in a freestyle skier

A male freestyle skier was found to have atrial fibrillation during a routine physiological assessment. This was found to be associated with the consumption of an unusually large amount of alcohol. Athletes should be counselled about the potential dangers of alcohol consumption before exhaustive exercise.

The upper limit of physiological cardiac hypertrophy in elite male and female athletes: the British experience

Establishment of upper normal limits of physiological hypertrophy in response to physical training is important in the differentiation of physiological and pathological left ventricular hypertrophy. The genetic differences that exist in the adaptive response of the heart to physical training and the causes of sudden cardiac death in young athletes indicate the need for population-specific normal values. Between September 1994 and December 2001, 442 (306 male, 136 female) elite British athletes from 13 sports were profiled. Standard two-dimensional guided M-mode and Doppler echocardiography were employed to evaluate left ventricular morphology and function. Eleven (2.5%) athletes, competing in a range of sports including judo, skiing, cycling, triathlon, rugby and tennis, presented with a wall thickness >13 mm, commensurate with a diagnosis of hypertrophic cardiomyopathy. Eighteen (5.8%) male athletes presented with a left ventricular internal diameter during diastole (LVIDd) >60 mm, with an upper limit of 65 mm. Of the 136 female athletes, none where found to have a maximum wall thickness >11 mm. Left ventricular internal diameter was <60 mm in all female athletes. Systolic and diastolic function were within normal limits for all athletes. Upper normal limits for left ventricular wall thickness and LVIDd are 14 mm and 65 mm for elite male British athletes, and 11 mm and 60 mm for elite female British athletes. Values in excess of these should be viewed with caution and should prompt further investigation to identify the underlying mechanism.

Reducing conduct problems among children of battered women

This study was an experimental evaluation of an intervention designed to reduce conduct problems among children of battered women. Participants were 36 families (mothers and children) in which the mother had sought shelter because of relationship violence and had at least 1 child (4-9 years old) with clinical levels of conduct problems. The intervention consisted of 2 primary components: (a) providing instrumental and emotional support and (b) teaching child management skills to mothers. Families were randomly assigned to either the intervention condition or the existing services comparison condition and were assessed on 5 occasions over 16 months after shelter departure. Compared with families receiving existing services, children in the intervention condition improved at a faster rate, the proportion of children displaying clinical levels of conduct problems was greatly diminished, and mothers displayed greater improvements in child management skills.

Release of biologically active TGF-beta from airway smooth muscle cells induces autocrine synthesis of collagen

In severe or chronic asthma, there is an increase in airway smooth muscle cell (ASMC) mass as well as an increase in connective tissue proteins in the smooth muscle layer of airways. Transforming growth factor-beta (TGF-beta) exists in three isoforms in mammals and is a potent regulator of connective tissue protein synthesis. Using immunohistochemistry, we had previously demonstrated that ASMCs contain large quantities of TGF-beta1-3. In this study, we demonstrate that bovine ASMC-derived TGF-beta associates with the TGF-beta latency binding protein-1 (LTBP-1) expressed by the same cells. The TGF-beta associated with LTBP-1 localizes TGF-beta extracellularly. Furthermore, plasmin, a serine protease, regulates the secretion of a biologically active form of TGF-beta by ASMCs as well as the release of extracellular TGF-beta. The biologically active TGF-beta released by plasmin induces ASMCs to synthesize collagen I in an autocrine manner. The autocrine induction of collagen expression by ASMCs may contribute to the irreversible fibrosis and remodeling seen in the airways of some asthmatics.

Structure and in vitro function of human subcutaneous small arteries in mild heart failure

The structure and function of subcutaneous small arteries from patients with mild heart failure (n = 27) 6-43 mo after myocardial infarction were compared with vessels from healthy control subjects (n = 10). Patients were randomized to treatment with placebo or the angiotensin-converting enzyme inhibitor ramipril starting 3-10 days after myocardial infarction. Dissected arterial vessels were mounted on a wire myograph for measurement of morphology and isometric tension. Morphology was not different in arteries from the three groups. Responses to norepinephrine, angiotensin II, and electrical field stimulation were similar in arteries from placebo-treated patients with mild heart failure and control subjects. Similarly, endothelium-dependent and -independent relaxation was normal in arteries from patients with mild heart failure. Ramipril therapy was associated with functional alterations: vasoconstrictor responses to norepinephrine and angiotensin II were significantly enhanced compared with placebo (P < 0.001). These data suggest that vascular structure and function are not different in vitro in subcutaneous arteries from placebo-treated patients with mild heart failure. Angiotensin-converting enzyme inhibitor therapy is associated with enhanced vasoconstriction to norepinephrine and angiotensin II, which may reflect upregulation of receptor-mediated events.

Influence of isradipine and spirapril on left ventricular hypertrophy and resistance arteries

Left ventricular hypertrophy is a common clinical feature in hypertensive patients and may be associated with structural changes in vessel morphology. In an open prospective trial, we evaluated 14 patients with previously untreated hypertension (163 +/- 2/104 +/- 2 mm Hg) and an echocardiographically determined left ventricular mass index of 141.6 +/- 5.2 g/m2, indicating left ventricular hypertrophy. We obtained a gluteal skin biopsy sample before starting treatment to investigate subcutaneous small-artery (approximately 200 to 400 microns diameter) morphology and function. Patients then received antihypertensive treatment with a combination of spirapril (3 or 6 mg) and isradipine (2.5 or 5 mg). Echocardiographic recordings were made after 6 months and 1 year, and a final biopsy was taken after 1 year. After 1 year, blood pressure was significantly reduced to 142 +/- 3/ 90 +/- 1 mm Hg (P < .001), and left ventricular mass index decreased significantly to 105.3 +/- 5.8 g/m2 (P < .001). Baseline media-lumen ratio (7.64 +/- 0.48%) was not markedly reduced (7.21 +/- 0.55%), although a decrease occurred in 7 of 12 evaluable patients. Norepinephrine-induced vasoconstriction was markedly reduced after 1 year. In conclusion, a significant regression of left ventricular hypertrophy was obtained after 1 year of treatment with spirapril and isradipine, whereas a similar reduction in medial thickness relative to lumen diameter of subcutaneous small arteries could not be observed in all patients. Reversal of structural changes in resistance vessels may require a longer treatment period in patients with proven left ventricular hypertrophy.

Effect of antihypertensive treatment on small arteries of patients with previously untreated essential hypertension

In a double-blind randomized trial, the effects of treatment with an angiotensin-converting enzyme (ACE) inhibitor (perindopril) and a beta-blocker (atenolol) on small artery structure were compared in previously untreated essential hypertensive patients. Subjects (diastolic blood pressure > or = 100 and < or = 120 mm Hg) were randomly assigned to treatment for 12 months with either perindopril (n = 13, 4 to 8 mg/d) or atenolol (n = 12, 50 to 100 mg/d); the dosage was adjusted upward and in some cases combined (n = 5, perindopril; n = 2, atenolol) with thiazide diuretic to achieve target blood pressure (diastolic blood pressure below 90 mm Hg). Before and at the end of treatment, gluteal biopsies were taken under local anesthetic; from these biopsies, two small arteries were dissected and mounted on a myograph for morphometry. The reduction in blood pressure with atenolol (drop in mean blood pressure 28.4 +/- 1.8 mm Hg) was greater than with perindopril (20.6 +/- 1.8 mm Hg, P < .05). Perindopril treatment caused an increase in small artery diameter (231 +/- 14 to 274 +/- 13 microns, P < .05) and a reduction in the ratio of media thickness to lumen diameter (7.94 +/- 0.65% to 5.96 +/- 0.42%, P < .05), whereas atenolol had no effect (246 +/- 14 to 231 +/- 13 microns and 7.14 +/- 0.47% to 6.79 +/- 0.45%, respectively). The change in small artery morphology caused by perindopril was not accompanied by any change in media cross-sectional area, suggesting that the change was due to "remodeling."(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of small artery sensitivity and morphology in pressurized and wire-mounted preparations

Two in vitro techniques, the pressurized flow chamber and the wire myograph, commonly employed to study the structure and function of small arteries, were compared. Mesenteric arteries from Wistar-Kyoto (WKY) rats were studied at a transmural pressure (44 +/- 1 mmHg) at which they elicit optimum contraction in each system. Differences in morphological parameters were minor, but there was a marked difference in the vasoconstrictor response of arteries mounted in the wire myograph and pressure system. Endothelium-intact pressurized arteries were significantly more sensitive to norepinephrine and constricted to angiotensin II, whereas wire-mounted vessels did not. These differences in agonist-induced contraction remained after removal of the endothelium. Blockade of amine uptake mechanisms indicated that the difference in norepinephrine sensitivity between the systems resulted from an enhanced influence of neuronal amine uptake in wire-mounted arteries. These data demonstrate that the technique employed has important functional implications for the study of small artery responses in vitro and that the results of investigations into the pathophysiology of small arteries are dependent on the method used and must be interpreted with caution.

Neurotransmission in Human Resistance Arteries: Contribution of α1- and α2- Adrenoceptors but Not P2- Purinoceptors

The contribution of postjunctional alpha 1- and alpha 2-adrenoceptors and P2-purinoceptors to the neuroeffector response was examined in isolated segments of human subcutaneous resistance arteries. Electrical field stimulation (EFS, 20 V, 0.2 ms, 1-25 Hz) elicited a maximum contractile response which was 38.2 +/- 1.6% of that elicited by exogenously applied (5 microM) noradrenaline (n = 56). Tetrodotoxin (1 microM), used to inhibit neurotransmission, reduced the electrically evoked response to 24.7 +/- 4.4% (n = 10) of the control response. The alpha 1-adrenoceptor antagonist prazosin (1 microM) reduced the maximum EFS contractile response to 64.8 +/- 5.5% of the control response (n = 17). Application of the alpha 2-adrenoceptor antagonist yohimbine (0.1 microM) reduced the maximum EFS response to 68.2 +/- 8.2% of the control response (n = 9). In the presence of prazosin plus yohimbine at the above-mentioned concentrations the maximum response to EFS was reduced to 47.6 +/- 6.7% (n = 11). Responses following alpha-blockade were not statistically different from those in the presence of tetrodotoxin, but the mean responses indicate that a non-adrenergic component to the EFS response cannot be discounted. Desensitisation of P 2-purinoceptors with alpha, beta-methylene ATP had no effect on responses to EFS; therefore under the conditions studied these receptors do not appear to be involved in neurotransmission. These results confirm the presence of postjunctional alpha 1- and alpha 2-adrenoceptors in human resistance arteries and for the first time demonstrate that the postjunctional alpha 2-adrenoceptor is important in modulating vascular responses elicited by intramural sympathetic nerve fibres.

Arterial neuroeffector responses in early and mature spontaneously hypertensive rats

Intramural sympathetic neuroeffector responses and presynaptic regulation of neurotransmission by amine uptake and alpha 2-adrenergic receptors were examined in young (5-week-old) and mature (12-week-old) spontaneously hypertensive rats (SHR) and were compared with those of age-matched Wistar-Kyoto (WKY) control rats. Electrical field stimulation (20 V, 0.2-msec pulse width, 3-second pulse train each minute, 5-100 Hz) elicited contractile responses from isolated mesenteric arteries mounted in a myograph. There was a significant difference between the sensitivity of arteries to electrical field stimulation in the two age groups, with arteries from 12-week-old rats being more sensitive than arteries from 5-week-old animals. Also, there was a significant age-strain interaction: the sensitivity of arteries from SHR to electrical field stimulation increased dramatically with age compared with that of WKY rat arteries. Cocaine significantly increased the sensitivity to electrical field stimulation after inhibition of presynaptic alpha 2-adrenergic receptors, and had a significantly greater effect in arteries from 5-week-old SHR compared with WKY controls. This would reflect an overactive neuronal amine uptake mechanism in young SHR. At 12 weeks there was no significant interstrain difference in the effect of cocaine. Yohimbine increased the sensitivity to electrical field stimulation both before and after inhibition of neuronal amine uptake, but there was no difference in its effect with age or strain. Therefore, although sensitivity to sympathetic nerve stimulation varies with age in the SHR, there is no evidence that this can be ascribed to alpha 2-adrenergic receptor function.

Pulmonary vascular smooth muscle: biochemical and mechanical developmental changes

To evaluate the developmental changes in pulmonary vascular smooth muscle contractile protein content, mechanical properties, and their contribution to the high resistance characteristic of the fetal and immediate neonatal period, we studied pulmonary vessels of fetal, newborn, and adult sheep, as well as newborn and adult pigs. Strips of the second- through fifth-generation vessels were dissected, and their content of tissue total smooth muscle cell protein, myosin, and actin-to-myosin ratio were measured; the mechanical properties of the second-generation vascular strips were also studied. For all ages the smooth muscle protein and myosin content of the second-generation vessels were significantly greater than for the lower pulmonary vascular orders (P less than 0.05). The myosin content in fetal sheep (0.77 +/- 0.03 micrograms/mg wet tissue) was similar to that of the newborn (0.79 +/- 0.04) and adult (0.86 +/- 0.05). However, the smooth muscle protein content (7.94 +/- 0.21 micrograms/mg wet tissue) and the actin-to-myosin ratio of the pulmonary vascular tissue of the fetus (1.00 +/- 0.04) were lower (P less than 0.01) in the fetal than in the newborn (9.16 +/- 0.26 and 1.60 +/- 0.12) and adult (9.38 +/- 0.3 and 1.60 +/- 0.11, respectively). No differences were observed for these parameters between the newborn and adult pig. Stress (16.5 +/- 1.7 mN/mm2) and the maximum shortening capacity (13.0 +/- 1.5% of optimal length) in the newborn pulmonary vascular strips were significantly greater than for the fetus (6.8 +/- 1.4 and 5.9 +/- 1.0, respectively) but similar to those of the adult sheep.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous growth of the motor system in the axolotl

During growth of the axolotl, motor neurons, and muscle fibres are added to the motor system. By double labelling neurons with tritiated thymidine and retrogradely transported HRP, we show that some motor neurons are born at postembryonic stages. Further analysis of motor neurons with the aid of HRP reveals this population of newly born cells relatively frequently in small (5-7 cm long) axolotls, but only rarely in large (7-13 cm long) axolotls. Evidence is presented that suggests that these immature cells are in the process of migrating from close to the ependyma out to the ventral horn. HRP transport also reveals growth cones of advancing axons within spinal nerves in animals up to 6 cm in length. Cell counts by light and electron microscopic methods show that muscle fibres are generated throughout larval life in the iliotibialis, a typical limb muscle. This analysis provides data consistent with the notion that new muscle fibres are added from a localised growth zone situated at the superficial edge of the muscle. These results are discussed in terms of the correlation between continuous growth of the motor system and the ability of the axolotl to functionally repair lesions to the peripheral nervous system.

Effect of admission nutritional status on length of hospital stay

Malnutrition is a large problem among patients admitted to U.S. hospitals and is an area of increasing concern for GI health care professionals. We conducted a prospective assessment of the admission nutritional status of 500 consecutive patients admitted to the Huntington Veterans Affairs Medical Center. Admission nutritional status was compared to the length of hospital stay (LOS). Nutritional status was calculated based on three equally weighted and easily obtained parameters--serum albumin, total peripheral blood lymphocyte counts and unintentional weight loss over time. A significant difference (p less than 0.01) was noted for the LOS between patients with normal, mildly abnormal and moderately abnormal nutritional status as compared with the patients with severe malnutrition. The length of hospital stay progressively increased with deterioration of nutritional status. The GI practitioner is in a key position to assess nutritional status of hospitalized patients. If malnutrition can be documented on hospital admission, attempts can be made to reverse the malnutrition and hopefully diminish LOS.

The pattern of innervation in serially duplicated axolotl limbs: further evidence for the existence of local pathway cues?

The innervation of the biceps muscle was examined in regenerated and vitamin A-induced serially duplicated axolotl forelimbs using retrograde transport of horseradish peroxidase. The regenerated biceps muscle becomes innervated by motor neurones in the same position in the spinal cord as the normal biceps motor pool. In previous experiments in which the innervation of a second copy of a proximal limb muscle was examined in serially duplicated limbs (Stephens, Holder & Maden, 1985), the duplicate muscle was found to become innervated by motor neurones that would normally have innervated distal muscles. In the present study, the innervation of the second copy of biceps was examined under conditions designed to encourage nerve sprouting from ‘correct’ biceps axons. Following either partial limb denervation or denervation coupled with removal of the proximal biceps, the second copy of the muscle was still innervated by inappropriate motor neurones, which again would normally innervate distal limb muscles. These results are interpreted as evidence for the necessity for an appropriate local environment for axonal growth to allow reformation of a correct pattern of motor innervation in the regenerated limb.