Microwave-assisted activation and modulator removal in zirconium MOFs for buffer-free CWA hydrolysis.

A novel, facile and efficient method was developed for the activation of acetic acid modulated zirconium MOFs. The protocol involves briefly heating the material in water using microwave irradiation. MOF-808, DUT-84 and UiO-66 were all activated in this manner to remove the modulator and organic solvent from the framework post synthesis, with retention of MOF integrity post activation. The degree of activation was characterised by the use of TGA and NMR. The catalytic activity of the activated MOFs and their non-activated counterparts was investigated for chemical warfare agent (CWA) hydrolysis. Upon activation, an increase in the rate of hydrolysis was observed in the degradation of CWA simulant dimethyl 4-nitrophenyl phosphate (DMNP). MOF-808 and DUT-84 were also screened as catalysts for the hydrolysis of the V-series agent VM, with remarkable half-lives obtained for MOF-808 in the absence of any buffers. Currently employed MOF activation procedures involve the use of additional organic solvents post synthesis; we believe this method to be ideally efficacious for the organic desolvation of zirconium MOFs and removing modulator additives.

The short-term cost of falls, poisonings and scalds occurring at home in children under 5†years old in England: multicentre longitudinal study.

BACKGROUND: Childhood falls, poisonings and scalds, occurring predominantly in the home, are an important public health problem, yet there is limited evidence on the costs of these injuries to individuals and society. OBJECTIVES: To estimate National Health Service (NHS) and child and family costs of falls, poisonings and scalds. METHODS: We undertook a multicentre longitudinal study of falls, poisonings and scalds in children under 5 years old, set in acute NHS Trusts across four UK study centres. Data from parental self-reported questionnaires on health service resource use, family costs and expenditure were combined with unit cost data from published sources to calculate average cost for participants and injury mechanism. RESULTS: 344 parents completed resource use questionnaires until their child recovered from their injury or until 12 months, whichever came soonest. Most injuries were minor, with >95% recovering within 2 weeks, and 99% within 1 month of the injury. 61% emergency department (ED) attendees were not admitted, 35% admitted for ≤1 day and 4% admitted for ≥2 days. The typical healthcare cost of an admission for ≥2 days was estimated at £2000-3000, for an admission for ≤1 day was £700-1000 and for an ED attendance without admission was £100-180. Family costs were considerable and varied across injury mechanisms. Of all injuries, scalds accrued highest healthcare and family costs. CONCLUSIONS: Falls, poisonings and scalds incur considerable short-term healthcare and family costs. These data can inform injury prevention policy and commissioning of preventive services.

An investigation of EEG, genetic and cognitive markers of treatment response to antidepressant medication in patients with major depressive disorder: a pilot study.

The aim of this study was to investigate if biomarkers in QEEG, genetic and neuropsychological measures are suitable for the prediction of antidepressant treatment outcome in depression. Twenty-five patients diagnosed with major depressive disorder were assessed twice, pretreatment and at 8-wk follow-up, on a variety of QEEG and neuropsychological tasks. Additionally, cheek swab samples were collected to assess genetic predictors of treatment outcome. The primary outcome measure was the absolute decrease on the HAM-D rating scale. Regression models were built in order to investigate which markers contribute most to the decrease in absolute HAM-D scores. Patients who had a better clinical outcome were characterized by a decrease in the amplitude of the Auditory Oddball N1 at baseline. The 'Met/Met' variant of the COMT gene was the best genetic predictor of treatment outcome. Impaired verbal memory performance was the best cognitive predictor. Raised frontal Theta power was the best EEG predictor of change in HAM-D scores. A tentative integrative model showed that a combination of N1 amplitude at Pz and verbal memory performance accounted for the largest part of the explained variance. These markers may serve as new biomarkers suitable for the prediction of antidepressant treatment outcome.

Mixed treatment comparison with multiple outcomes reported inconsistently across trials: evaluation of antivirals for treatment of influenza A and B.

We present a mixed treatment meta-analysis of antivirals for treatment of influenza, where some trials report summary measures on at least one of the two outcomes: time to alleviation of fever and time to alleviation of symptoms. The synthesis is further complicated by the variety of summary measures reported: mean time, median time and proportion symptom free at the end of follow-up. We compare several models using the deviance information criteria and the contribution of different evidence sources to the residual deviance to aid model selection. A Weibull model with exchangeable treatment effects that are independent for each outcome but have a common random effect mean for the two outcomes gives the best fit according to these criteria. This model allows us to summarize treatment effect on two outcomes in a single summary measure and draw conclusions as to the most effective treatment. Amantadine and Oseltamivir were the most effective treatments, with the probability of being most effective of 0.56 and 0.37, respectively. Amantadine reduces the duration of symptoms by an estimated 2.8 days, and Oseltamivir 2.6 days, compared with placebo. The models provide flexible methods for synthesis of evidence on multiple treatments in the absence of head-to-head trial data, when different summary measures are used and either different clinical outcomes are reported or where the same outcomes are reported at different or multiple time points.

Chemical coding and central projections of gastric vagal afferent neurons.

Vagal afferents that innervate gastric muscle or mucosa transmit distinct sensory information from their endings to the nucleus of the tractus solitarius (NTS). While these afferent subtypes are functionally distinct, no neurochemical correlate has been described and it is unknown whether they terminate in different central locations. This study aimed to identify gastric vagal afferent subtypes in the nodose ganglion (NG) of ferrets, their terminal areas in NTS and neurochemistry for isolectin-B4 (IB4) and calcitonin gene-related peptide (CGRP). Vagal afferents were traced from gastric muscle or mucosa and IB4 and CGRP labelling assessed in NG and NTS. 7 +/- 1% and 6 +/- 1% of NG neurons were traced from gastric muscle or mucosa respectively; these were more likely to label for CGRP or for both CGRP and IB4 than other NG neurons (P < 0.01). Muscular afferents were also less likely than others to label with IB4 (P < 0.001). Less than 1% of NG neurons were traced from both muscle and mucosa. Central terminals of both afferent subtypes occurred in the subnucleus gelatinosus of the NTS, but did not overlap completely. This region also labelled for CGRP and IB4. We conclude that while vagal afferents from gastric muscle and mucosa differ little in their chemical coding for CGRP and IB4, they can be traced selectively from their peripheral endings to NG and to overlapping and distinct regions of NTS. Thus, there is an anatomical substrate for convergent NTS integration for both types of afferent input.

Use of evidence in economic decision models: practical issues and methodological challenges.

This paper outlines the current 'state of play' regarding the use of evidence in decision modelling and highlights both practical issues and methodological challenges related to identifying, combining and reporting evidence to inform decision model parameters and structure. Based on discussions at two MRC HSRC-funded workshops consisting of 37 experts from a range of disciplines (i.e. decision-makers, health economists, information specialists, operations researchers and statisticians), it aims to derive a multi-disciplinary standpoint on the appropriate use of evidence in economic decision models and, where applicable, offer some suggestions for good modelling practice. Gaps in the established methodology knowledge base are identified for future research.

The contribution of apolipoprotein E alleles on cognitive performance and dynamic neural activity over six decades.

Neuroimaging shows brain-functional differences due to apolipoprotein E (APOE) polymorphisms may exist decades before the increased risk period for Alzheimer's disease, but little is known about their effect on cognition and brain function in children and young adults. This study assessed 415 healthy epsilon2 and epsilon4 carriers and matched epsilon3/epsilon3 controls, spanning ages 6-65, on a range of cognitive tests. Subjects were also compared on a new dynamical measure of EEG activity during a visual working memory task using alphabetical stimuli. epsilon4 subjects had better verbal fluency compared to epsilon3, an effect that was strongest in 51-65 year-olds. No epsilon4 deficits in cognition were found. In 6-15 year-olds, there were differences in total spatio-temporal wave activity between epsilon3 and epsilon4 subjects in the theta band, approximately 200ms post-stimulus. Differences in brain function in younger epsilon4 subjects and superior verbal fluency across the entire age range suggest that the APOE epsilon4 allele is an example of antagonistic pleiotropy.

Meta-analysis of mixed treatment comparisons at multiple follow-up times.

Mixed treatment comparisons (MTC) meta-analysis is a methodology for making inferences on relative treatment effects based on a synthesis of both direct and indirect evidence on multiple treatment contrasts. This is particularly useful in the context of cost-effectiveness analysis and medical decision making. Here, we extend these methods to a more complex situation where trials report results at one or more, different yet fixed, follow-up times. These methods are applied to an illustrative data set combining evidence on healing rates under six different treatments for gastro-esophageal reflux disease (GERD). A series of Bayesian hierarchical models based on piece-wise exponential hazards is developed that borrow strength across the MTC networks and also across time points. These include models for absolute and relative treatment effects, models with fixed or random effects over time, random walk models, and models with homogeneous or heterogeneous between-trials variation. The deviance information criterion (DIC) is used to guide model development and selection. Models for absolute treatment effects generate materially different rankings of the treatments than models that separate the trial-specific baselines from the relative treatment effects. The extent of between-trials heterogeneity in treatment effects depends on treatment contrast. In discussion we note that models of this type have a very wide potential application.

The impact of diabetes on current revascularisation practice and clinical outcome in patients with critical lower limb ischaemia.

OBJECTIVE: To compare current revascularisation practice and outcome in diabetic and non-diabetic patients presenting with critical limb ischaemia (CLI) to a single vascular surgeon. METHODS: Data for 113 patients presenting with CLI were collected prospectively over a 3-year period. Forty-four (39%) were diabetic. Treatment was classified as percutaneous angioplasty, arterial reconstruction, primary major amputation, and conservative therapy. Main outcome measures were 30-day mortality, major amputation, survival, and amputation-free survival. RESULTS: Diabetic patients were more likely to present with gangrene, give a history of angina, be treated with nitrates and statins, and have lower cholesterol levels. No significant differences were found in the initial treatment options between diabetics and non-diabetics: angioplasty 39 vs 26%, surgical revascularisation 34 vs 33%, primary major amputation 9% vs 17%, and conservative treatment 11 vs 19% (p = ns in all). There were eight deaths (7%) within 30-days. At follow-up (1-44 months, median 14 months), rates of major amputation and death for the entire population were 23 and 8%, respectively. The 12-month cumulative survival and amputation-free survival rates were 90 and 72%, respectively. When comparing diabetic to non-diabetic patients, there were no significant differences in the 30-day mortality (6.8 vs 7.2%, p = 0.4), cumulative survival (93 vs 89% at 12 months, log-rank test: 0.00, p = 0.9), amputation-free survival (71 vs 73% at 12 months, log-rank test: 0.00, p = 0.99), and major amputation rates (22.7 vs 23.1% at 12 months, p = 0.96). Similarly, there were no differences in limb salvage rates between diabetic and non-diabetic patients undergoing revascularisation procedures (78 vs 90% at 12 months, log-rank test: 2.04, p = 0.15). CONCLUSIONS: In current practice, an aggressive multidisciplinary approach in diabetic patients presenting with CLI leads to similar limb salvage, amputation-free survival, mortality, and major amputation rates to those seen in non-diabetic patients. The presence of diabetes should not deter clinicians from attempting revascularisation by means of angioplasty or surgical reconstruction.

The cost-effectiveness of influenza vaccination of healthy adults 50-64 years of age.

Influenza can cause significant morbidity and mortality. Influenza vaccination is an effective and safe strategy in the prevention of influenza. Currently the National Health Service (NHS) vaccinates 'at-risk' individuals only. This definition includes everyone over 65 years of age but excludes individuals 50-64 years of age unless they have an additional risk factor, such as underlying heart disease or lung disease. In order to examine the cost-effectiveness of an extension of the vaccination policy to include this age group we constructed an economic model to estimate the costs and benefits of vaccination from both a health service and a societal perspective. Data to populate the model was obtained from the literature and the outcome measure used was the quality adjusted life year (QALY). Influenza vaccination prevented an estimated 4508 cases (95% CI: 2431-7606) per 100,000 vaccinees per influenza season for a net cost to the NHS of pound653,221 (95% CI: 354,575-1,072,257). The net cost increased to pound1,139,069 (95% CI 27,052-2,030,473) when non-NHS costs were included and the estimated cost-per-QALY were pound6174 and pound10,766 for NHS and all costs respectively. Extension of the current immunisation policy has the potential to generate a significant health benefit at a comparatively low cost.

The cost of clinically significant urinary storage symptoms for community dwelling adults in the UK.

OBJECTIVES: To estimate the cost of clinically significant urinary storage symptoms (CSUSS), including costs borne by the National Health Service (NHS) and individuals, in terms of the use of goods and services in community-dwelling adults. SUBJECTS AND METHODS: The subjects were community-dwelling adults aged >/= 40 years and living in Leicestershire. The prevalence of CSUSS was estimated using a postal questionnaire with a randomly selected sample of 23 182 respondents. The costs associated with CSUSS were estimated using home interviews with 613 cases with and 523 subjects without CSUSS. Cases were defined on the basis of urinary symptoms of leakage, urgency, frequency and nocturia. Willingness-to-pay was used to measure intangible costs as an indicator of the value of alleviating symptoms. RESULTS: The estimated total annual cost to the NHS for treating CSUSS cases in community-dwelling adults was pound 536 million at 1999/2000 prices ( pound 303 million and pound 233 million for men and women, respectively). The total value of costs borne by individuals was estimated to be pound 207 million ( pound 29 million and pound 178 million for men and women, respectively). This gives total annual costs related to the use of services of pound 743 million. There were large intangible costs borne by individuals estimated to be pound 669 million ( pound 301 and pound 368 million for men and women) for the UK in terms of willingness-to-pay. CONCLUSIONS: The costs of CSUSS in the community amounted to approximately 1.1% of overall NHS spending for 1999/2000. Personally borne and intangible costs are also large and important components of the costs of CSUSS. There are large gender differences in the proportion of costs borne by the NHS, i.e. 91% of male and 57% of female costs.

The post-operative mortality of ruptured abdominal aortic aneurysm repair.

INTRODUCTION: Late peri-operative death after ruptured abdominal aortic aneurysm (RAAA) repair is usually due to multiple-organ failure. The aim of this study was to identify any factors that are associated with mortality in this group of patients. METHODS: A retrospective case-note review of a single decade's operative experience of RAAA repair in a single centre. Only those patients with confirmed rupture at laparotomy were included. Sixty-three pre- intra- and post-operative variables were recorded where possible for each patient who survived surgery and the initial 24-hours post-operatively. Multi-variate analysis was performed using stepwise logistic regression. The P-POSSUM, RAAA-POSSUM, RAAA-POSSUM (physiology only), V-POSSUM, and V-POSSUM (physiology only) models were all compared to determine how each performed in these patients. RESULTS: Two hundred and twenty-three cases of confirmed RAAA were identified, of whom 139 survived the operation and initial 24-hours post-operatively. In-hospital mortality in this group of patients was 32.4%. Variables significantly associated with mortality after multi-variate analysis, were low intra-operative systolic blood pressure, the presence of a consultant anaesthetist at the initial operation and the development of cardiac, renal or gastro-intestinal complications. All POSSUM models except the V-POSSUM and P-POSSUM (physiology only) models demonstrated no significant lack of fit in this dataset. DISCUSSION: Factors associated with delayed peri-operative death after RAAA are not the same as those previously found to be associated with overall peri-operative mortality after RAAA repair.

Meta-analysis of randomized clinical trials comparing open and laparoscopic inguinal hernia repair.

BACKGROUND: The aim was to conduct a meta-analysis of the randomized evidence to determine the relative merits of laparoscopic (LIHR) and open (OIHR) inguinal hernia repair. METHODS: A search of the Medline, Embase, Science Citation Index, Current Contents and PubMed databases identified all randomized clinical trials that compared OIHR and LIHR and were published in the English language between January 1990 and the end of October 2000. The meta-analysis was prepared in accordance with the Quality of Reporting of Meta-analyses (QUOROM) statement. The six outcome variables analysed were operating time, time to discharge from hospital, return to normal activity and return to work, postoperative complications and recurrence rate. Random effects meta-analyses were performed using odds ratios and weighted mean differences. RESULTS: Twenty-nine trials were considered suitable for meta-analysis. Some 3017 hernias were repaired laparoscopically and 2972 hernias were repaired using an open method in 5588 patients. For four of the six outcomes the summary point estimates favoured LIHR over OIHR; there was a significant reduction of 38 per cent in the relative odds of postoperative complications (odds ratio 0.62 (95 per cent confidence interval (c.i.) 0.46 to 0.84); P = 0.002), 4.73 (95 per cent c.i. 3.51 to 5.96) days in time to return to normal activity (P < 0.001), 6.96 (95 per cent c.i. 5.34 to 8.58) days in time to return to work (P < 0.001) and 3.43 (95 per cent c.i. 0.35 to 6.50) h in time to discharge from hospital (P = 0.029). There was a significant increase of 15.20 (95 per cent c.i. 7.78 to 22.63) min in the mean operating time for LIHR (P < 0.001). The relative odds of short-term recurrence were increased by 50 per cent for LIHR compared with OIHR, although this result was not statistically significant (odds ratio 1.51 (95 per cent c.i. 0.81 to 2.79); P = 0.194). CONCLUSION: LIHR was associated with earlier discharge from hospital, quicker return to normal activity and work, and significantly fewer postoperative complications than OIHR. However, the operating time was significantly longer and there was a trend towards an increase in the relative odds of recurrence after laparoscopic repair.

Trial introduction of the Willis dropped ovary technique for spaying cattle in northern Australia.

OBJECTIVE: To compare the Willis dropped ovary technique with traditional spaying methods in extensive beef cattle herds in northern Australia. PROCEDURE: Three field trials were conducted simultaneously at different sites in northern Australia in 1996-97. Brahman and Brahman-Shorthorn cross heifers (n = 219, 2 years, 250 to 378 kg) and cows (n = 211, 3 to 16 years, 256 to 540 kg) were allocated by stratified randomisation to three treatments: spaying using the Willis dropped ovary technique (WDOT); spaying using traditional paralumbar and vaginal methods; and unspayed. Following these procedures, these nonpregnant, nonlactating cattle were then exposed to bulls (4 per 100 females) under extensive rangeland conditions for 12 months during which time weight, body condition, pregnancy and ovarian function were monitored and compared. RESULTS: Pregnancy rates varied from 60 to 90% for entire heifers and 80 to 100% for entire cows depending on site. The traditional spay methods were 100% successful in preventing pregnancy; the WDOT was 92 to 97% effective, depending on operator experience. The number of deaths was the same or higher in Willis spayed animals than other groups. Weight changes were similar in all groups at the three sites over the trial period. The time taken to spay using the WDOT was similar to or less than that required for the traditional methods. Uterine abnormalities were not observed in animals spayed with the WDOT, there were however 30 (12.4%) animals where excision of the ovary was incomplete; the still-attached ovarian remnant presumably accounting for the three pregnant animals in this group. CONCLUSION: The WDOT suffers from requiring a high degree of skill in transrectal ovarian manipulation. There were more deaths and more pregnancies than with traditional spay methods. More experienced operators can be expected to achieve lower mortalities, better contraception and higher processing rates. Pregnancy will occur as a consequence of ovarian remnants unless care is taken to ensure removal of the entire ovary.

Total costs and predictors of costs in individuals with early inflammatory polyarthritis: a community-based prospective study.

OBJECTIVE: To estimate the health service, non-health service and total costs and predictors of costs in individuals with early inflammatory polyarthritis (IP). METHODS: We conducted a prospective longitudinal study over a 6-month period. The participants were a random sample of 133 individuals who had enrolled with the community-based Norfolk Arthritis Register (NOAR) database between 1994 and 1999. The main outcome measures were the mean (per person) 6-month health service cost, non-health-service cost and total cost associated with IP. RESULTS: One hundred and fifteen of the 133 individuals who were recruited into the study completed 6 months of follow-up. The mean 6-month total cost was estimated to be 2800 pounds sterling per person, of which 14% was health service costs and the remainder non-health-service costs. Higher total costs were associated with lower health status and rheumatoid factor positivity. CONCLUSIONS: Early IP has a considerable impact on both the health-care system and, more importantly, society. Non-health-service costs (i.e. costs incurred by the individual with the disease, their family and friends) account for a substantial proportion (86%) of the total costs associated with early IP.

Bull selection and use in northern Australia. 5. Social behaviour and management.

Calf output of bulls was derived using DNA typing for paternity following multiple-sire mating at two sites in northern Australia. At Swan's Lagoon Beef Cattle Research Station, 12, mixed-age, Brahman cross bulls were continuously mated with an average of 325 females in a 22km2 open-savannah paddock. Water was available in two troughs. Behaviour of the bulls and location of cows were monitored. At Kamilaroi Station, 2- to 2.5-year-old Brahman bulls were introduced to the study. Twenty-four bulls (HIGH%) were mated in an 84km2 paddock for 3.5 months to 411 heifers in 1995/1995 and for 4.5 months to 350 heifers and 320 first-lactation cows in 1995/1996. A second group of 10 bulls (LOW%) selected on reproductive soundness was mated concurrently in a neighbouring 60km2 paddock to 411 heifers in 1995/1995 and to 350 heifers and 298 first-lactation cows in 1995/1996. In each paddock in both years, 300-350 females were expected to cycle during mating. Both paddocks were flat and semi-forested and water was available only at troughs. At both sites, detailed physical and reproductive examinations of all bulls were conducted prior to and post-mating.Calf output of individual bulls was highly variable but repeatable (r=0.6-0.7) between years. Up to 90% of the 270-380 calves resulting from each mating were sired by between 6 and 8 bulls. Reducing from 3.7 to 2.8% bulls:females at Swan's Lagoon did not delay conceptions. At Kamilaroi, reproductively sound bulls achieved an estimated 5-6 conceptions per week over the peak mating period when sufficient cycling females were available. Differences in pregnancy rates between paddocks appeared due to differences in nutrition and it appeared that conceptions were not delayed with LOW% vs. HIGH% bulls. Variance between bulls in calf output was substantially lower when fewer bulls were used. Bull attrition occurred each year in the HIGH% paddock but not in the LOW% paddock. Calf output was unrelated to body condition of bulls. Seven of the 12 bulls in one 2-year period at Swan's Lagoon appeared to restrict their movement range to 250-750ha for 90-100% of the time. These ranges expanded when the bull:female ratio was reduced. Only one of the nine bulls remained within a 500ha home range for at least 85% of the time during peak mating in 1998 at 2.8% bulls:females. In previous years with 3.7% bulls:females, up to eight of the 12 bulls had remained within a 500ha home range for 85% of the time. Bull behaviour related to high calf output included restricted movement range, grazing with females at a majority of observations, stable social behaviour, and social dominance. These observations demonstrate that multiple-sire mating of reproductively sound Brahman and Brahman-derived bulls at 2.5% of cycling females will not jeopardise herd fertility under extensive management in northern Australia.

Decision analytical economic modelling within a Bayesian framework: application to prophylactic antibiotics use for caesarean section.

Economic evaluation of health care interventions based on decision analytic modelling can generate valuable information for health policy decision makers. However, the usefulness of the results obtained depends on the quality of the data input into the model; that is, the accuracy of the estimates for the costs, effectiveness, and transition probabilities between the different health states of the model. The aim of this paper is to review the use of Bayesian decision models in economic evaluation and to demonstrate how the individual components required for decision analytical modelling (i.e., systematic review incorporating meta-analyses, estimation of transition probabilities, evaluation of the model, and sensitivity analysis) may be addressed simultaneously in one coherent Bayesian model evaluated using Markov Chain Monte Carlo simulation implemented in the specialist Bayesian statistics software WinBUGS. To illustrate the method described, a simple probabilistic decision model is developed to evaluate the cost implications of using prophylactic antibiotics in caesarean section to reduce the incidence of wound infection. The advantages of using the Bayesian statistical approach outlined compared to the conventional classical approaches to decision analysis include the ability to: (i) perform all necessary analyses, including all intermediate analyses (e.g., meta-analyses) required to derive model parameters, in a single coherent model; (ii) incorporate expert opinion either directly or regarding the relative credibility of different data sources; (iii) use the actual posterior distributions for parameters of interest (opposed to making distributional assumptions necessary for the classical formulation); and (iv) incorporate uncertainty for all model parameters.

GABA(B)R expressed on vagal afferent neurones inhibit gastric mechanosensitivity in ferret proximal stomach.

GABA(B)-receptor (GABA(B)R) agonists reduce transient lower esophageal sphincter relaxation (TLESR) and reflux episodes through an action on vagal pathways. In this study, we determined whether GABA(B)R are expressed on vagal afferent neurones and whether they modulate distension-evoked discharge of vagal afferents in the isolated stomach. Vagal mehanoreceptor activity was recorded following distensions of the isolated ferret proximal stomach before and after perfusion with the GABA(B)R-selective agonists baclofen and 3-aminopropylphosphinic acid (3-APPiA). Retrograde labeling and immunohistochemistry were used to identify GABA(B)R located on vagal afferent neurones in the nodose ganglia. Vagal afferent fibers responded to isovolumetric gastric distension with an increase in discharge. The GABA(B)-receptor agonists baclofen (5 x 10(-5) M) and 3-APPiA (10(-6) to 10(-5) M) but not muscimol (GABA(A)-selective agonist: 1.3 x 10(-5) M) significantly decreased afferent distension-response curves. The effect of baclofen (5 x 10(-5) M) was reversed by the GABA(B)-receptor antagonist CGP 62349 (10(-5) M). Over 93% of retrogradely labeled gastric vagal afferents in the nodose ganglia expressed immunoreactivity for the GABA(B)R. GABA(B)R expressed on vagal afferent fibers directly inhibit gastric mechanosensory activity. This is likely a contributing mechanism to the efficacy of GABA(B)-receptor agonists in reducing TLESR and reflux episodes in vivo.

Glycoconjugates on the surface of epididymal spermatozoa in a marsupial, the brushtail possum, Trichosurus vulpecula.

Variation in localization and distribution of saccharides on the sperm surface of a marsupial, the brushtail possum, Trichosurus vulpecula, was compared between spermatozoa from the caput and cauda epididymides. Spermatozoa were subjected to the following treatments: (i) unfixed and fixed spermatozoa were stained with fluorescein-labelled lectins; (ii) unfixed spermatozoa were incubated with lectins for determination of agglutination; and (iii) spermatozoa were incubated with detergent to remove the plasmalemma, the glycoproteins were separated on SDS-PAGE and western blots were stained with biotinylated lectins. Many of the fluorescein isothiocyanate (FITC)-labelled lectins bound selectively to the sperm surface, and marked differences were found in lectin staining affinity between caput and cauda epididymal spermatozoa. Incubation of spermatozoa from the cauda epididymidis with neuraminidase reversed many of the differences in staining of the cauda epididymal spermatozoa, indicating masking of some terminal saccharides by sialic acid. Agglutination of spermatozoa from the caput epididymidis occurred after incubation with Concanavalin A (ConA) and soybean agglutinin (SBA), but agglutination was less extensive for spermatozoa from the cauda epididymidis. Western blot analysis indicated several ConA-positive bands in caput sperm extracts, but fewer positive bands in the cauda sperm extracts, whereas SBA stained four bands from caput but none from the cauda epididymal spermatozoa. These results demonstrate extensive glycosylation of the surface proteins of spermatozoa from the caput epididymidis and significant differences in spermatozoa from the cauda epididymidis. In general, the findings indicate similar glycosylation of the surface of marsupial spermatozoa to those from eutherian mammals despite marked differences in their morphology and early divergence of marsupials from eutherian mammals. It would appear that this situation differs markedly from that in sub-mammalian vertebrates.