Consumers' Perspectives and Experiences of Prebiotics and Probiotics for Gut Health in Chronic Kidney Disease

OBJECTIVES

Nutrition supplementation, including prebiotics and probiotics, is a therapeutic strategy for modulating the gut microbiome in chronic kidney disease (CKD). However, the acceptability of gut-targeted supplements in this population remains largely unexplored. This study aims to describe the perceptions of nutrition supplementation, and the acceptability and experiences of pre- and probiotics in adults with Stage 3-4 CKD.

DESIGN AND METHODS

Semi-structured interview study of adults with Stage 3-4 CKD (n = 30), aged 41-80 (mean 68) years, who completed a 12-month prebiotic and probiotic intervention or placebo, were interviewed between January and March 2019. Interviews were transcribed verbatim and analyzed thematically.

RESULTS

Five themes were identified: integrating and sustaining routine supplementation (flexibility in prescription of prebiotics and probiotics, fitting in with regular routines); striving for health benefits (hoping to improve kidney health, hoping to improve general health, confirming health benefits); facilitating pre- and probiotic supplementation (perceiving pre- and probiotics as safe, side-effects from taking pre- and probiotics); empowering knowledge (valuing the opportunity to increase knowledge of gut health); and considerations for future use (questioning credibility of health claims, average palatability of prebiotic powder, cost concerns).

CONCLUSIONS

Adults with Stage 3-4 CKD found pre- and probiotic supplements to be acceptable and complementary gut-targeted supplements. Individual preferences for nutrition supplementation should be considered alongside health knowledge to enhance uptake and adherence in practice.

Diet Quality and Protein-Bound Uraemic Toxins: Investigation of Novel Risk Factors and the Role of Microbiome in Chronic Kidney Disease

OBJECTIVE

This study aims to explore the associations between diet quality, uraemic toxins, and gastrointestinal microbiota in the chronic kidney disease (CKD) population.

METHODS

This is a baseline cross-sectional study of adults with CKD participating in a randomized controlled trial of prebiotic and probiotic supplementation. Dietary intake was measured using a seven-day diet history method, administered by a specialist dietitian. Diet quality was assessed using plant-based diet index (PDI) (overall PDI, healthy PDI, and unhealthy PDI), food group analysis, protein intake, fiber intake, and dietary protein-to-fiber ratio. Serum uraemic toxins (free and total; indoxyl sulfate and p-cresyl sulfate) were determined by ultraperformance liquid chromatography. Gastrointestinal microbiota richness, diversity, composition, and functional capacity were analyzed via metagenomic sequencing.

RESULTS

Sixty-eight adults [median age: 70 (interquartile range: 58-75) years, 66% male] with an estimated glomerular filtration rate of 34 ± 11 mL/min/1.73 m² were included, with 40 participants completing the optional fecal substudy. Dietary fiber intake was associated with lower levels of total indoxyl sulfate, whereas the healthy plant-based diet index was associated with lower levels of free p-cresyl sulfate. A higher protein-to-fiber ratio was associated with an increased relative abundance of unclassified members of order Oscillospirales. Intake of vegetables and whole grains was correlated with Subdoligranulum formicile, whereas an unclassified Prevotella species was correlated with potatoes and food items considered discretionary, including sweet drinks, sweet desserts, and animal fats.

CONCLUSIONS

Diet quality may influence uraemic toxin generation and gut microbiota diversity, composition, and function in adults with CKD. Well-designed dietary intervention studies targeting the production of uraemic toxins and exploring the impact on gut microbiome are warranted in the CKD population.

The Impact of Systematic Review Automation Tools on Methodological Quality and Time Taken to Complete Systematic Review Tasks: Case Study

BACKGROUND

Systematic reviews (SRs) are considered the highest level of evidence to answer research questions; however, they are time and resource intensive.

OBJECTIVE

When comparing SR tasks done manually, using standard methods, versus those same SR tasks done using automated tools, (1) what is the difference in time to complete the SR task and (2) what is the impact on the error rate of the SR task?

METHODS

A case study compared specific tasks done during the conduct of an SR on prebiotic, probiotic, and synbiotic supplementation in chronic kidney disease. Two participants (manual team) conducted the SR using current methods, comprising a total of 16 tasks. Another two participants (automation team) conducted the tasks where a systematic review automation (SRA) tool was available, comprising of a total of six tasks. The time taken and error rate of the six tasks that were completed by both teams were compared.

RESULTS

The approximate time for the manual team to produce a draft of the background, methods, and results sections of the SR was 126 hours. For the six tasks in which times were compared, the manual team spent 2493 minutes (42 hours) on the tasks, compared to 708 minutes (12 hours) spent by the automation team. The manual team had a higher error rate in two of the six tasks-regarding Task 5: Run the systematic search, the manual team made eight errors versus three errors made by the automation team; regarding Task 12: Assess the risk of bias, 25 assessments differed from a reference standard for the manual team compared to 20 differences for the automation team. The manual team had a lower error rate in one of the six tasks-regarding Task 6: Deduplicate search results, the manual team removed one unique study and missed zero duplicates versus the automation team who removed two unique studies and missed seven duplicates. Error rates were similar for the two remaining compared tasks-regarding Task 7: Screen the titles and abstracts and Task 9: Screen the full text, zero relevant studies were excluded by both teams. One task could not be compared between groups-Task 8: Find the full text.

CONCLUSIONS

For the majority of SR tasks where an SRA tool was used, the time required to complete that task was reduced for novice researchers while methodological quality was maintained.

MO590GUT HEALTH INTERVENTIONS IN CHRONIC KIDNEY DISEASE: ACCEPTABILITY AND FEASIBILITY OF OF SYNBIOTIC SUPPLEMENTATION

Background and Aims

Synbiotics, co-administered prebiotics and probiotics, have emerged over the last decade as an innocuous intervention targeting the microbial generation of the uraemic toxins, indoxyl sulphate (IS) and p-cresyl sulphate (PCS). However, most trials to date are of short duration (2-24 weeks). In order to inform translation into clinical practice, it is imperative to consider the efficacy of synbiotic supplementation as a long-term intervention. The aims of this study were to evaluate the feasibility and acceptability (including symptoms and adherence) of long-term synbiotic supplementation in adults with chronic kidney disease (CKD), as well as explore the perspectives of these patients on nutrition supplementation for gut health, including strategies to optimise adherence in practice.

Method

SYNERGY II was a double-blind randomised controlled trial in adults (>18years) with stage 3-4 CKD over 12 months. The intervention comprised of daily prebiotic powder (2 x 10g/day resistant starch) and probiotic supplementation (single sachet of 6g/day multi strain 4.5x1011CFU) or placebo control (waxy maize powder and a sachet of maltodextrin). Adherence to nutrition supplementation was defined as participants consuming >80% of the prescribed sachets/powder. Symptoms were monitored via Gastrointestinal Symptom Rating Scale (GSRS) and Bristol Stool Score (BSS). Semi-structured interviews were conducted in person or by telephone with a sample of 30 participants at the completion of the intervention. The interviews explored experiences and perspectives regarding frequencies, timing and difficulties experienced with each aspect of the intervention and overall perceptions of the intervention as a strategy to improve gut health.

Results

Sixty-eight participants [66% male, median age 70 (IQR 58-75) years] were consented and randomised to either intervention or control groups, with a mean estimated glomerular filtration rate of 34 ± 11 mL/min/1.73m2. A total of 56 participants (82%) completed the 12-month intervention with no differences in withdrawals between groups (p=0.6). One participant from each group withdrew at week 2, citing palatability of the study product as the reason for withdrawal. Overall adherence to study supplementation was excellent in both intervention and placebo groups [median intake 92.1% (85.9-95.2%) placebo versus 89.5% (84.4-94.5%) synbiotic; P=0.4)]. Overall, there was no significant change from baseline to end of study visit for mean BSS (3.6 ± 1.4 to 3.6 ± 1.4 placebo versus 3.6 ± 1.1 to 4.1 ± 1.2 synbiotic, P=0.13), mean bowel movements (1.3 ± 0.6 to 1.6 ± 0.9 placebo versus 1.3 ± 0.6 to 1.8 ± 1.0 synbiotic, P=0.70) or GSRS [1.3 (1.1 - 1.9) to 1.3 (1.1 - 1.5) placebo versus 1.1 (1.1 - 1.5) to 1.3 (1.1 - 1.5) synbiotic, P=0.83]. Acceptability components described by participants were appreciating convenience and improving health and well-being. Participants discussed the following feasibility components: integrating easily into lifestyle and social accountability. Tablets or capsules were the preferred supplement formulation with a probiotic drink made from a SCOBY (synbiotic culture of bacteria and yeast) the least preferred.

Conclusion

Among adults with stage 3-4 CKD, synbiotic supplementation is a well-tolerated and acceptable form of nutrition supplementation. People with CKD would prefer nutrition supplements to be formulated as a tablet or capsule, which is an important consideration when translating into clinical practice.

FC 082DIET QUALITY, PROTEIN-BOUND URAEMIC TOXINS AND GASTROINTESTINAL MICROBIOME IN CHRONIC KIDNEY DISEASE

Background and Aims

Individuals with chronic kidney disease (CKD) have significantly increased risk of cardiovascular mortality which is only partially explained by Framingham risk factors. There is a growing body of evidence linking the gut-derived uraemic toxins indoxyl sulphate (IS) and p-cresyl sulphate (PCS) with accelerated kidney disease progression and cardiovascular burden in CKD. Whilst the effect of specific nutrients on uraemic toxin generation has been explored, few studies have characterised the impact of diet quality on the gastrointestinal microbiome in the CKD population. This study aims to explore the associations between dietary quality, protein-bound uraemic toxins and gastrointestinal microbiome in adults with CKD.

Method

This was a baseline cross-sectional study of adults with stage 3 to 4 CKD who were enrolled in a randomised controlled trial of prebiotic and probiotic supplementation. Habitual dietary intake was measured using a 7-day diet history method by a specialist Dietitian. Diet quality was assessed using food group analysis; protein intake, fibre intake, dietary protein:fibre ratio and adherence to plant-based diet index (PDI) (overall PDI, healthy PDI, unhealthy PDI). Serum uraemic toxins (free and total; IS and PCS) were determined by ultra-performance liquid chromatography. Metagenomic sequencing was used to determine gastrointestinal microbiota richness, diversity, composition and functional capacity.

Results

There were 68 CKD patients [66% male, median age 70 (IQR 58-75) years] with a mean estimated glomerular filtration rate of 34 ± 11 mL/min/1.73m2. Greater adherence to a hPDI was associated with lower levels of free PCS [-0.021 µmol/L (95% CI -0.042 to -0.001)], while a higher intake of dietary fibre intake was associated with lower levels of free IS [-0.022 µmol/L (95% CI -0.043 to -0.001)]. Compositionally, the gastrointestinal microbiota of this cohort was dominated by members of the phyla Firmicutes and Bacteroidetes. Supervised analysis at the species level demonstrated that 21% of variance in gastrointestinal microbial composition could be attributed to protein:fibre ratio (F=1.27, p=0.04). Further, a higher protein:fibre ratio was associated with an increased relative abundance of unclassified members of order Oscillospirales. Subdoligranulum formicile was correlated with dietary intake of vegetables and wholegrains while an unclassified Prevotella species was correlated with food items considered discretionary including sweet drinks, sweet desserts, animal fats and potatoes.

Conclusion

The study suggests that habitual diets that are higher in fibre and plant-based foods may positively influence uraemic toxin levels and gut microbiota diversity and composition in adults with CKD. These findings provide rationale for well-designed dietary intervention studies targeting the production of uraemic toxins and exploring the impact on gut microbiome in the CKD population.

A Renal Clinician's Guide to the Gut Microbiota

It is increasingly recognized that the gut microbiota plays a role in the progression of chronic diseases and that diet may confer health benefits by altering the gut microbiota composition. This is of particular relevance for chronic kidney disease (CKD), as the gut is a source of uremic retention solutes, which accumulate as a result of impaired kidney function and can exert nephrotoxic and other harmful effects. Kidney dysfunction is also associated with changes in the composition of the gut microbiota and the gastrointestinal tract. Diet modulates the gut microbiota, and there is much interest in the use of prebiotics, probiotics, and synbiotics as dietary therapies in CKD, as well as dietary patterns that beneficially alter the microbiota. This review provides an overview of the gut microbiota and its measurement, its relevance in the context of CKD, and the current state of knowledge regarding dietary manipulation of the microbiota.

Prebiotic, Probiotic, and Synbiotic Supplementation in Chronic Kidney Disease: A Systematic Review and Meta-analysis

OBJECTIVE

Gut dysbiosis has been implicated in the pathogenesis of chronic kidney disease (CKD). Restoring gut microbiota with prebiotic, probiotic, and synbiotic supplementation has emerged as a potential therapeutic intervention but has not been systematically evaluated in the CKD population.

DESIGN AND METHODS

This is a systematic review. A structured search of MEDLINE, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, and the International Clinical Trials Register Search Portal was conducted for articles published since inception until July 2017. Included studies were randomized controlled trials investigating the effects of prebiotic, probiotic, and/or synbiotic supplementation (>1 week) on uremic toxins, microbiota profile, and clinical and patient-centered outcomes in adults and children with CKD.

RESULTS

Sixteen studies investigating 645 adults met the inclusion criteria; 5 investigated prebiotics, 6 probiotics, and 5 synbiotics. The quality of the studies (Grades of Recommendation, Assessment, Development and Evaluation) ranged from moderate to very low. Prebiotic, probiotic, and synbiotic supplementation may have led to little or no difference in serum urea (9 studies, 345 participants: mean difference [MD] -0.30 mmol/L, 95% confidence interval [CI] -2.20 to 1.61, P = .76, I² = 53%), indoxyl sulfate (4 studies, 144 participants: MD -0.02 mg/dL, 95% CI -0.09 to 0.05, P = .61, I² = 0%), and p-cresyl sulfate (4 studies, 144 participants: MD -0.13 mg/dL, 95% CI -0.41 to 0.15, P = .35, I² = 0%). Prebiotic supplementation may have slightly reduced serum urea concentration (4 studies, 105 participants: MD -2.23 mmol/L, 95% CI -3.83 to -0.64, P = .006, I² = 11). Of the 2 studies investigating microbiota changes, synbiotic interventions significantly increased Bifidobacterium. Supplement effects on clinical outcomes were uncertain.

CONCLUSIONS

There is limited evidence to support the use of prebiotics, probiotics, and/or synbiotics in CKD management.

Inhibition of myostatin protects against diet-induced obesity by enhancing fatty acid oxidation and promoting a brown adipose phenotype in mice

AIMS/HYPOTHESIS

Although myostatin-null (Mstn (-/-)) mice fail to accumulate fat in adipose tissue when fed a high-fat diet (HFD), little is known about the molecular mechanism(s) behind this phenomenon. We therefore sought to identify the signalling pathways through which myostatin regulates accumulation and/or utilisation of fat.

METHODS

Wild-type, Mstn (-/-) and wild-type mice treated with soluble activin type IIB receptor (sActRIIB) were fed a control chow diet or an HFD for 12 weeks. Changes in gene expression were measured by microarray and quantitative PCR. Histological changes in white adipose tissue were assessed together with peripheral tissue fatty acid oxidation and changes in circulating hormones following HFD feeding.

RESULTS

Our results demonstrate that inactivation of myostatin results in reduced fat accumulation in mice on an HFD. Molecular analysis revealed that metabolic benefits, due to lack of myostatin, are mediated through at least two independent mechanisms. First, lack of myostatin increased fatty acid oxidation in peripheral tissues through induction of enzymes involved in lipolysis and in fatty acid oxidation in mitochondria. Second, inactivation of myostatin also enhanced brown adipose formation in white adipose tissue of Mstn (-/-) mice. Consistent with the above, treatment of HFD-fed wild-type mice with the myostatin antagonist, sActRIIB, reduced the obesity phenotype.

CONCLUSIONS/INTERPRETATION

We conclude that absence of myostatin results in enhanced peripheral tissue fatty acid oxidation and increased thermogenesis, culminating in increased fat utilisation and reduced adipose tissue mass. Taken together, our data suggest that anti-myostatin therapeutics could be beneficial in alleviating obesity.

Myostatin-deficient mice exhibit reduced insulin resistance through activating the AMP-activated protein kinase signalling pathway

AIMS/HYPOTHESIS

Myostatin-null mice (Mstn(-/-)) have reduced body fat and increased tolerance to glucose. To date the molecular mechanisms through which myostatin regulates body fat content and insulin sensitivity are not known. Therefore, the aim of the current study was to identify signalling pathways through which myostatin regulates insulin sensitivity.

METHODS

Wild-type (WT) mice and Mstn(-/-) mice were fed either a control chow diet or a high fat diet (HFD) for 12 weeks. Glucose tolerance testing and insulin stimulated glucose uptake by M. extensor digitorum longus (EDL) were used as variables to determine insulin sensitivity. Quantitative PCR, Western blotting and enzyme assays were used to monitor AMP-activated protein kinase (AMPK) levels and activity.

RESULTS

Mstn(-/-) mice exhibited reduced fat accumulation and peripheral insulin resistance when compared with WT mice, even when they were fed an HFD. Furthermore, treatment with a myostatin antagonist also increased insulin sensitivity during HFD. Consistent with increased insulin sensitivity, we also detected elevated levels of GLUT4, AKT, p-AKT and insulin receptor substrate-1 in Mstn(-/-) muscles. Molecular analysis showed that there is increased expression and activity of AMPK in Mstn(-/-) muscles. Furthermore, we also observed an increase in the AMPK downstream target genes, Sirt1 and Pgc-1α (also known as Ppargc1a), in skeletal muscle of Mstn(-/-) mice.

CONCLUSIONS/INTERPRETATION

We conclude that myostatin inactivation leads to increased AMPK levels and activity resulting in increased insulin sensitivity of skeletal muscle. We propose that, by regulating AMPK in skeletal muscle and adipose tissues, myostatin plays a major role in regulating insulin signalling.

Scottish Stroke Research Network: the first three years

Research networks were introduced in the UK to facilitate and improve clinical research and stroke was seen as a priority topic for local research network development. The Scottish Stroke Research Network (SSRN) is one of 11 stroke research networks in the UK. In this article we review the progress of the Scottish Stroke Research Network in the three years since inception. Between 2006-2009 the number of active hospital research sites has increased from 10 to 22 expanding to involve 20 stroke research nurses. There was a corresponding 58% increase in recruitment of participants into stroke studies, from 376 in 2006/07 to 594 in 2008/09. The majority (17/20) of our current studies are interventional. Data from one of these, the CLOTs trial (Clots in Legs Or sTocking after Stroke), demonstrates that the annual recruitment in Scotland increased from a median of 94 (range 6-122) patients per year in the six years before the SSRN, to 140 (135-158) patients per year after SSRN involvement. We currently screen about 50% of Scottish stroke patients and approximately 5% of Scottish stroke patients are participating in research studies that we support. The SSRN has made good progress in the first three years. Increasing the recruitment of screened patients remains a challenge.

Listening to people with intellectual disabilities who misuse alcohol and drugs

There is a dearth of research that has explored alcohol/drug use and misuse by people with intellectual disabilities. The aims of the present study were twofold: (1) to examine the insights of 10 people with intellectual disabilities into the reasons why they may misuse alcohol or drugs, and what impact this behaviour may have on them; and (2) to explore the services that they receive. Ten individuals with intellectual disabilities who were deemed to be misusing alcohol/drugs were purposively selected and interviewed. One overarching theme of the reasons for such misuse was labelled as 'self-medicating against life's negative experiences'. This was divided into two sub-themes: 'psychological trauma' and 'social distance from the community'. All the participants reported that their main source of support came from intellectual disability services, acting in both educational and liaison roles. Although seven of the individuals were referred to mainstream addiction services, they perceived this service as negative. In order to address these underlying problems, better access to a wider range of specialist services is required. Intellectual disability and mainstream addiction service providers also need to be more effective in the prevention and treatment of substance misuse by employing techniques such as motivational interviewing.

Oxidative modification of triacylglycerol-rich lipoproteins

Lipoprotein oxidation is thought to play a pivotal role in the evolution of atherosclerosis. Low-density lipoprotein (LDL) is the main source of oxidized lipid in the arterial wall. Oxidation of LDL alters its properties in a number of ways, making it more atherogenic, but oxidation of other lipoprotein classes may also be important. Common mechanisms are likely to contribute to the oxidation of all lipoprotein classes, with enzyme-mediated oxidation likely to be most important. Antioxidant content, fatty acid composition, particle size and the presence of seeding hydroperoxides also influence oxidative reactions. Larger triglyceride-rich lipoproteins are less likely to enter the arterial wall than LDL, but when oxidized will deliver a greater oxidant load to the arterial wall.

Quality of care in family planning clinics in Jamaica. Do clients and providers agree?

This paper uses data from 199 providers and 20 simulated clients collected at 50 public sector and Non Governmental Organization (NGO) health facilities islandwide in 1995 to compare the two groups' views on quality of care of family planning services. Each of the five components of quality of care studied can be improved in Jamaica. Nearly two-thirds of the simulated clients felt able to freely choose a contraceptive method; however, more adequate and appropriate information needs to be imparted to clients through improved counselling, including promotion of dual method use (against STD/HIV/AIDS and conception). The requirement that a woman must be menstruating to receive services has inadvertently resulted in many clients going away empty-handed (without counselling or condoms) when they visit family planning clinics. While providers generally treat clients well, training and service delivery practices need to be revised to improve the technical competence of providers. All of the providers would recommend these clinics to others, compared to a little over half of the simulated clients. Both the providers and simulated clients said that privacy should be strengthened, particularly in small facilities in rural areas. Many of these aspects of quality of care are being improved in Jamaica's public sector health facilities. Managers can learn more about quality of care by seeking the knowledge, opinions and experiences of both providers and clients.

Physiological responses to mixing in large scale bioreactors

Escherichia coli fed-batch cultivations at 22 m3 scale were compared to corresponding laboratory scale processes and cultivations using a scale-down reactor furnished with a high-glucose concentration zone to mimic the conditions in a feed zone of the large bioreactor. Formate accumulated in the large reactor, indicating the existence of oxygen limitation zones. It is suggested that the reduced biomass yield at large scale partly is due to repeated production/re-assimilation of acetate from overflow metabolism and mixed acid fermentation products due to local moving zones with oxygen limitation. The conditions that generated mixed-acid fermentation in the scale-down reactor also induced a number of stress responses, monitored by analysis of mRNA of selected stress induced genes. The stress responses were relaxed when the cells returned to the substrate limited and oxygen sufficient compartment of the reactor. Corresponding analysis in the large reactor showed that the concentration of mRNA of four stress induced genes was lowest at the sampling port most distant from the feed zone. It is assumed that repeated induction/relaxation of stress responses in a large bioreactor may contribute to altered physiological properties of the cells grown in large-scale bioreactor. Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.

Transmission of viral disease in the operating room setting

The transmission of viral disease in the operating room is an evolving problem. Advances in transfusion medicine have made blood supply safer than ever, whereas changes in transfusion practice have minimized the amount of blood transfused. The epidemiology of viral infection is changing in both the general population and among healthcare workers. Vaccination and prevention hold the key to future risk reduction for patients and providers.

The procedural validity of retrospective case note diagnosis

OBJECTIVE

Deriving diagnoses from retrospective case note examination is a common practice in psychiatric research. The Operational Criteria (OPCRIT) diagnostic checklist is essentially a checklist built up of operational criteria defined by a comprehensive glossary and is designed to assign reliable diagnoses from case notes. However, the validity of such a procedure compared with procedures involving prospective assessment has never been tested. We examined the procedural validity of the OPCRIT diagnostic system in relation to four other diagnostic procedures mostly employing prospectively gathered information.

METHOD

Three experienced psychopathology raters rated the case notes and clinical abstracts, using the OPCRIT method of diagnostic assignment, of 50 subjects who had participated in an early procedural validity study as an adjunct to the DSM-IV Field Trial for psychotic disorders. The setting was the Early Psychosis Prevention and Intervention Centre (EPPIC), which focuses on first episode psychosis.

RESULTS

The pairwise concordance with the other procedures for DSM-III-R diagnoses assigned by OPCRIT using ratings derived from either the clinical abstracts or the case notes was found to be only poor to moderate when compared with the pairwise concordance of the four other procedures. The per cent agreement between OPCRIT clinical abstracts diagnoses and the other procedures ranged from 49% to 60% with kappa values between 0.30 and 0.45, and for OPCRIT case note diagnoses and the other procedures the per cent agreement range was between 44% and 57% and the kappa values were between 0.35 and 0.49.

CONCLUSIONS

The procedural validity of diagnoses assigned via the application of checklists of operational criteria to case notes and clinical abstracts alone is unacceptably poor. Such sources need to be buttressed by other data, particularly direct patient interview and informant material.

Preventative mental health care: accessing the target population

OBJECTIVE

Preventative approaches to mental illness are becoming a focus of clinical and research settings. To date, however, few clinical programs have been established with this primary aim. This descriptive paper summarises patterns of referral to one service providing clinical care for young people known to be at high risk of developing a psychotic illness.

METHODS AND RESULTS

A 20-month survey of referrals to the service revealed that most patients had a prolonged and circuitous route to assessment. Additionally, a lengthy time period elapsed between the onset of symptoms and initiation of help seeking.

CONCLUSIONS

Information arising from this survey may influence the development of strategies to improve access to this service and others aimed at the prevention of psychosis. Further, this information may affect the development of generalised preventative mental health services for young people.

Development of a Scottish physical activity questionnaire: a tool for use in physical activity interventions

OBJECTIVES

Three studies were undertaken to establish the reliability and validity of the Scottish physical activity questionnaire (SPAQ), developed to aid seven day recall of leisure and occupational physical activity.

METHODS

To establish reliability, SPAQs (n = 34) were completed on a Monday and the following Wednesday. Thus each questionnaire measured four identical days. To establish concurrent validity, 94 participants completed a SPAQ and an adapted stage of exercise behaviour change questionnaire. Responses to SPAQ were then analysed by stage of exercise behaviour change. In a further study of criterion validity, 30 volunteers wore a Caltrac motion sensor for four consecutive days, after which they completed a SPAQ.

RESULTS

In the first study, total physical activity had a coefficient of repeatability (R) of 53 minutes. Occupational physical activity showed a similar variance (R = 54.6 minutes) but leisure physical activity was more reliable (R = 29.3 minutes). The main variation in occupational physical activity was found to be walking (R = 39.8 minutes). In study 2, a one way analysis of variance showed the expected relation between physical activity and stage of exercise behaviour change, confirming the concurrent validity of SPAQ with the stage of exercise behaviour change model. In study 3, several erroneous recordings affected both SPAQ and the Caltrac results (kcal). After relevant corrections had been made, the correlation between the two measurement devices was 0.52 (p < 0.05).

CONCLUSIONS

SPAQ has been shown to be reliable and to hold strong concurrent validity and limited criterion validity. The main limitation in SPAQ appears to be the measurement of occupational walking. It is therefore recommended that further work be conducted to refine the measurement of this physical activity component. It is evident nonetheless that SPAQ can be used with confidence to measure outcomes in physical activity interventions when account is taken of its limitations.

Relative neuroprotective effects of dizocilpine and isoflurane during focal cerebral ischemia in the rat

Both dizocilpine (MK-801) and isoflurane antagonize glutamatergic neurotransmission. In this study, we examined the relative neuroprotective effects of these drugs administered in equianesthetic doses before the onset of focal cerebral ischemia. Rats were anesthetized with 1.0%-1.5% isoflurane and surgically prepared for filament occlusion of the middle cerebral artery (MCAO). After preparation, one group (n = 22) remained anesthetized with 0.7% isoflurane. Another group (n = 18) was given dizocilpine (1 mg/kg intraperitoneally), and isoflurane was discontinued. The third group (n = 18) was allowed to awaken immediately after the onset of ischemia. MCAO persisted for 75 min. Epidural temperature was controlled at 37.5 degrees C during ischemia and the first 22 h of recovery. A 7-day recovery interval was allowed. Total infarction volumes (mean +/- SD) were less for the dizocilpine group (100 +/- 65 mm3) versus the awake group (182 +/- 36 mm3; P = 0.001). Infarction volumes did not differ significantly between the isoflurane group (142 +/- 81 mm3) and either the dizocilpine (P = 0.11) or the awake group (P = 0.15). Isoflurane was examined at doses used clinically but smaller than those found to reduce N-methyl-D-aspartate (NMDA)-mediated injury in vitro. This study supports the hypothesis that NMDA receptor activation is injurious during focal ischemia and that amelioration of focal ischemic brain damage by NMDA receptor antagonists persists under normothermic conditions.

IMPLICATIONS

Rats underwent focal cerebral ischemia with rigid maintenance of brain normothermia. The glutamate receptor antagonist dizocilpine was effective in reducing cerebral infarction size during persistent conditions of brain normothermia. In contrast, isoflurane administered at equianesthetic doses did not reduce infarction size. This study supports the hypothesis that N-methyl-D-aspartate receptor activation is injurious during focal ischemia and that amelioration of focal ischemic brain damage by N-methyl-D-aspartate receptor antagonists persists under normothermic conditions.

A series of non-quinoline cysLT1 receptor antagonists: SAR study on pyridyl analogs of Singulair

The structure-activity relationship of a series of styrylpyridine analogs of MK-0476 (montelukast, Singulair) is described. This work has led to the identification of a number of potent and orally active cysLT1 receptor (LTD4 receptor) antagonists including 2ab (L-733,321) as an optimized candidate.

Identification, purification, and characterization of a soluble interleukin (IL)-13-binding protein. Evidence that it is distinct from the cloned Il-13 receptor and Il-4 receptor alpha-chains

Interleukin-4 (IL-4) and interleukin-13 (IL-13) are structurally and functionally related cytokines which play an important role in the regulation of the immune response to infection. The functional similarity of IL-4 and IL-13 can be explained, at least in part, by the common components that form their cell surface receptors, namely the IL-4 receptor alpha-chain (IL-4Ralpha) and the IL-13 receptor alpha-chain (IL-13Ralpha). Soluble forms of the IL-4Ralpha have also been described and implicated in modulating the effect of IL-4. In this paper we describe the presence of a 45,000-50,000 Mr IL-13-binding protein (IL-13BP) in the serum and urine of mice. This protein binds IL-13 with a 100-300-fold higher affinity (KD = 20-90 pM) than does the cloned IL-13Ralpha (KD = 3-10 nM). In addition to this functional difference, the IL-13BP appears to be structurally and antigenically distinct from the IL-13Ralpha. Finally, unlike the cloned receptor, the IL-13BP acts as a potent inhibitor of IL-13 binding to its cell surface receptor, raising the possibility that it may be used to modulate the effects of IL-13 in vivo.

Leptin can induce proliferation, differentiation, and functional activation of hemopoietic cells

Many cytokines exert their biological effect through members of the hemopoietin receptor family. Using degenerate oligonucleotides to the common WSXWS motif, we have cloned from human hemopoietic cell cDNA libraries various forms of the receptor that was recently shown to bind the obesity hormone, leptin. mRNAs encoding long and short forms of the human leptin receptor were found to be coexpressed in a range of human and murine hemopoietic organs, and a subset of cells from these tissues bound leptin at the cell surface. Ectopic expression in murine Ba/F3 and M1 cell lines revealed that the long, but not the short, form of the leptin receptor can signal proliferation and differentiation, respectively. In cultures of murine or human marrow cells, human leptin exhibited no capacity to stimulate cell survival or proliferation, but it enhanced cytokine production and phagocytosis of Leishmania parasites by murine peritoneal macrophages. Our data provide evidence that, in addition to its role in fat regulation, leptin may also be able to regulate aspects of hemopoiesis and macrophage function.

The effects of plasma and brain magnesium concentrations on lidocaine-induced seizures in the rat

Lidocaine and MgSO4 are often coadministered to patients with pregnancy-induced hypertension. This study examined whether MgSO4 alters the lidocaine-seizure threshold in the rat and, if so, whether systemic MgSO4 administration is as effective as intracerebroventricular MgSO4 infusion. In Experiment 1, rats were administered 50% MgSO4 or 0.9% NaCl intravenously (IV) (20 microL/h) for 5 days. In Experiment 2, rats were administered 0.9% NaCl, 0.8% MgSO4, or 2.0% MgSO4 (10 microL/h) via intracerebroventricular infusion for 24 h. All rats then underwent continuous IV lidocaine infusion until onset of electroencephalographic seizures. In Experiment 1, plasma [Mg2+] was greater in the MgSO4 group (5.1 +/- 1.5 mg/dL vs 1.8 +/- 0.3 mg/dL) but neither the dose of lidocaine required to induce seizures (MgSO4 = 19 +/- 2 mg/kg; saline = 23 +/- 5 mg/kg) nor brain [Mg2+] (MgSO4 = 794 +/- 17 micrograms/g; saline = 788 +/- 33 micrograms/g) were changed. In Experiment 2, intracerebroventricular MgSO4 increased both brain [Mg2+] (2% MgSO4 = 923 +/- 79 micrograms/g; saline = 788 +/- 35 micrograms/g) and the lidocaine seizure dose (2% MgSO4 = 39 +/- 7 mg/kg; saline = 26 +/- 3 mg/kg). Although intracerebroventricular administration of MgSO4 produces an anticonvulsant effect, chronic hypermagnesemia does not alter whole brain [Mg2+] and therefore offers no protection from lidocaine-induced seizures in this model.

The prevalence of prodromal features of schizophrenia in adolescence: a preliminary survey

In most cases of schizophrenia the onset of frank psychosis is preceded by a period of prodromal features. This period has been relatively neglected by researchers and is potentially important in promoting early intervention. The prevalence of DSM-III-R schizophrenia prodrome symptoms was assessed as part (n = 657) of a large (n = 2525) questionnaire-based survey of high school students. Individual symptoms were highly prevalent and the prevalence of DSM-III-R prodromes ranged from 10 - 15% to 50%. Despite methodological weaknesses, the data suggest that DSM-III-R prodromal features are extremely prevalent among older adolescents and unlikely to be specific for subsequent schizophrenia. Clinically these features cannot be regarded as sufficient evidence of early schizophrenia and more accurate predictors of incipient schizophrenia need to be defined.

Interactions between NMDA and AMPA glutamate receptor antagonists during halothane anesthesia in the rat

There is increasing evidence that pharmacologic antagonism of glutamatergic neurotransmission can potentiate the anesthetic effects of drugs such as halothane. The purpose of this study was to examine the anesthetic interaction between glutamate receptor antagonists. A competitive NMDA receptor antagonist (CGS 19755) and an AMPA receptor antagonist (NBQX) were administered either alone or in combination prior to determination of the minimum alveolar concentration (MAC) for halothane in the rat. CGS 19755 caused a dose-dependent maximum reduction in halothane MAC of approximately 80%. Doses of NBQX, which were low enough to cause no change in MAC when administered alone, substantially reduced MAC when administered with subanesthetic doses of CGS 19755. This effect decreased as the dose of CGS 19755 was increased. Finally, halothane MAC was reduced to zero when NBQX, in a dose sufficient to reduce halothane MAC by approximately 35% if given alone, was added to a pharmacodynamically similar dose of CGS 19755. Although MAC is believed to predominantly reflect nocioception at the spinal cord level, the results suggests that pharmacologic blockade of glutamatergic neurotransmission is sufficient to result in deep levels of anesthesia. Further, the effect of combinations of NMDA and AMPA receptor antagonists on halothane MAC is consistent with an in vivo physiologic interaction between the NMDA and AMPA receptors.

Glycine receptor antagonism. Effects of ACEA-1021 on the minimum alveolar concentration for halothane in the rat

BACKGROUND

Glycine and glutamate binding sites are allosterically coupled at the N-methyl-D-aspartate (NMDA) receptor complex. Previous studies have shown that antagonism of glutamate at the NMDA receptor reduces the minimum alveolar concentration (MAC) for volatile anesthetics. 5-Nitro-6,7-dichloro-2,3-quinoxalinedione (ACEA-1021) is a competitive antagonist at the glycine recognition site of the NMDA receptor. The purpose of this study was to determine whether glycine receptor antagonism also reduces volatile anesthetic requirements in the rat.

METHODS

In experiment 1, Sprague-Dawley rats were anesthetized with halothane in 50% O2-balance N2 and their lungs mechanically ventilated. They were randomly assigned to one of three groups according to the dose of ACEA-1021 administered (0, 20, or 40 mg/kg intravenously; n = 6). The bolus dose of ACEA-1021 was followed by a continuous intravenous infusion of vehicle or ACEA-1021 at 14 mg.kg-1.h-1. Halothane MAC was then determined by the tail-clamp method. In experiment 2, awake rats were randomly assigned to groups according to the same dosages of ACEA-1021 as in experiment 1. Arterial CO2 tension and mean arterial pressure were recorded before and 5 and 30 min after the start of the infusion. The infusion was then stopped, and the time to recovery of the righting reflex was recorded.

RESULTS

In experiment 1, ACEA-1021 decreased halothane MAC (mean +/- SD) in a dose-dependent manner (control, 0.95 +/- 0.15 vol%; ACEA-1021 20 mg/kg, 0.50 +/- 0.14 vol%; ACEA-1021 40 mg/kg, 0.14 +/- 0.16 vol%; P < 0.01). In experiment 2, arterial CO2 tension was increased by ACEA-1021 (control, 38 +/- 3 mmHg; ACEA-1021 20 mg/kg, 43 +/- 3 mmHg; ACEA-1021 40 mg/kg, 48 +/- 2 mmHg; P < 0.01). Mean arterial pressure was not affected by any dose of ACEA-1021. The righting reflex was abolished in rats receiving ACEA-1021 40 mg/kg only and recovered 30 +/- 7 min after discontinuation of the infusion.

CONCLUSIONS

Halothane MAC reduction by glycine receptor antagonism was greater than that previously observed for antagonism of glutamate at the NMDA or AMPA receptor. In rats receiving ACEA-1021 only, minimal hemodynamic depression and moderate hypoventilation were observed. Antagonism of glycine at the NMDA receptor recognition site offers a potential mechanism of action of anesthesia.

Minimum alveolar concentration for halothane in the rat is resistant to effects of forebrain ischemia and reperfusion

BACKGROUND

Because glutamate antagonists can substantially alter the minimum alveolar concentration (MAC) of volatile anesthetics, glutamate has been implicated as an important neurotransmitter in processes contributing to the anesthetic state. Cerebral ischemia profoundly alters glutamatergic neurotransmission and thus may also alter halothane MAC.

METHODS

Fasted rats were surgically prepared for forebrain ischemia. One half of the animals served as operative shams (n = 24). Remaining rats underwent 10 min of bilateral carotid occlusion combined with systemic hypotension (n = 24). In animals in both groups brain circulation was restored for 1 h, 24 h, or 7 days (n = 8). At each of these intervals, MAC for halothane was determined by the tail-clamp method. Histologic damage in the hippocampus, cortex, caudoputamen, and thalamus was measured in animals allowed to survive 7 days.

RESULTS

Blood pressure, arterial blood gas tensions and pH, pericranial temperature, and plasma glucose values measured immediately before ischemia were similar among groups. Neither ischemia nor duration of reperfusion significantly altered halothane MAC as compared with operative shams (sham 1 h = 0.9 +/- 0.1 vol%, 24 h = 1.0 +/- 0.1 vol%, 7 days = 1.0 +/- 0.2 vol%; ischemia 1 h = 0.9 +/- 0.1 vol%, 24 h = 0.9 +/- 0.1 vol%, 7 days = 1.0 +/- 0.2 vol%). Histologic damage in the hippocampus and caudoputamen was severe in the ischemic group of animals. Mild injury was observed in the motor and cingulate cortex as well as the thalamus. There was no evidence of histologic injury in sham-operated animals.

CONCLUSIONS

The absence of effect of ischemic forebrain injury on halothane MAC is consistent with findings made in other models of supratentorial cerebral injury. These results support the contention that anatomic foci for motor responses elicited during MAC determination are localized at levels caudal to the forebrain.

Glutamatergic antagonism: effects on lidocaine-induced seizures in the rat

We tested the hypothesis that glutamate receptor antagonists increase the dose of lidocaine required to induce seizure activity. Sprague-Dawley rats were anesthetized with halothane in 40% O2/balance N2 and mechanically ventilated. After surgical preparation, halothane was discontinued. Normocapnia, normoxia, and normothermia were maintained. The electroencephalogram (EEG) and arterial blood pressure were monitored continuously. Rats were then randomized to one of six groups (control, one of three intravenous [i.v.] bolus doses of the competitive glutamate N-methyl-D-aspartate [NMDA] receptor antagonist CGS 19755, or one of two i.v. bolus and continuous infusion regimens of the competitive glutamate alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid [AMPA] receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo-(F)quinoxalline [NBQX]). Thirty minutes after onset of CGS 19755 or NBQX administration (end-tidal halothane < 0.2%), rats received a continuous i.v. infusion of 1.5% lidocaine until EEG seizures occurred. The duration of the infusion (min) and total lidocaine dose (mg/kg) administered were recorded. CGS 19755 increased the lidocaine seizure threshold in a log-linear dose-dependent fashion (P < 10(-6)). The largest dose of CGS 19755 (112.5 mg/kg) increased the time to initial EEG seizure activity more than twofold (e.g., control = 12.6 +/- 2.6 min; CGS 19755 = 28.6 +/- 6.9 min). The effect of AMPA receptor antagonism was less obvious because treatment resulted in an EEG morphology dissimilar to that observed in the CGS 19755 or control groups. Our findings indicate that competitive NMDA receptor antagonists (e.g., CGS 19755) increase the dose of lidocaine required for seizures.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of Plasmalyte 148 and 0.9% saline for intra-operative fluid replacement

Thirty patients undergoing major hepatobiliary or pancreatic surgery were randomly allocated to receive either 0.9% saline or Plasmalyte 148 (a balanced salt solution), at 15 ml.kg-1.h-1. Arterial blood gas analysis was performed before and after surgery. Plasma biochemistry (Na+, K+, Cl-, lactate) measurements were made before and after surgery and at 24 h after surgery. The patients receiving 0.9% saline had significantly increased chloride concentrations (p < 0.01), decreased standard bicarbonate concentrations (p < 0.01) and increased base deficit (p < 0.01) compared to those receiving Plasmalyte 148. There were no significant changes in plasma sodium or potassium or blood lactate concentrations in either group. The exclusive use of 0.9% saline intra-operatively can produce a temporary hyperchloraemic acidosis which could be given false pathological significance. In addition it may exacerbate an acidosis resulting from an actual pathological state. The use of a balanced salt solution such as Plasmalyte 148 may avoid these complications.

Does early administration of epidural analgesia affect obstetric outcome in nulliparous women who are in spontaneous labor?

BACKGROUND

Some studies suggest that epidural analgesia prolongs labor and increases the incidence of cesarean section, especially if it is administered before 5 cm cervical dilation. The purpose of the current study was to determine whether early administration of epidural analgesia affects obstetric outcome in nulliparous women who are in spontaneous labor.

METHODS

Informed consent was obtained from 344 healthy nulliparous women with a singleton fetus in a vertex presentation, who requested epidural analgesia during spontaneous labor at at least 36 weeks' gestation. Each patient was randomized to receive either early or late epidural analgesia. Randomization occurred only after the following conditions were met: (1) the patient requested pain relief at that moment, (2) a lumbar epidural catheter had been placed, and (3) the cervix was at least 3 cm but less than 5 cm dilated. Patients in the early group immediately received epidural bupivacaine analgesia. Patients in the late group received 10 mg nalbuphine intravenously. Late-group patients did not receive epidural analgesia until they achieved a cervical dilation of at least 5 cm or until at least 1 h had elapsed after a second dose of nalbuphine. Ten of the 344 patients were excluded because of a protocol violation or voluntary withdrawal from the study.

RESULTS

Early administration of epidural analgesia did not increase the incidence of oxytocin augmentation, prolong the interval between randomization and the diagnosis of complete cervical dilation, or increase the incidence of malposition of the vertex at delivery. Also, early administration of epidural analgesia did not result in an increased incidence of cesarean section or instrumental vaginal delivery. Seventeen (10%) of 172 women in the early group and 13 (8%) of 162 women in the late group underwent cesarean section (relative risk for the early group 1.22; 95% confidence interval 0.62-2.40). Patients in the early group had lower pain scores between 30 and 150 min after randomization. Infants in the late group had lower umbilical arterial and venous blood pH and higher umbilical venous blood carbon dioxide tension measurements at delivery.

CONCLUSIONS

Early administration of epidural analgesia did not prolong labor, increase the incidence of oxytocin augmentation, or increase the incidence of operative delivery, when compared with intravenous nalbuphine followed by late administration of epidural analgesia, in nulliparous women who were in spontaneous labor at term.

Laryngotracheal stenosis: a serious complication of percutaneous tracheostomy

Tracheostomy in patients requiring prolonged artificial ventilation in intensive care is increasingly being performed by a percutaneous dilatational technique, in preference to the standard surgical method. Since its introduction numerous series have reported favourably on its general safety in the short-term, but there have been few reports of longer term follow-up of patients. We present four cases of laryngotracheal stenosis, a previously unreported complication associated with the technique, and discuss the relevance of these to the future practice of percutaneous tracheostomy.

Sevoflurane and halothane reduce focal ischemic brain damage in the rat. Possible influence on thermoregulation

BACKGROUND

There has been little systematic examination concerning the comparative effects of the anesthetized versus the awake state on outcome from cerebral ischemia. This experiment evaluated infarct volume and neurologic function in rats subjected to temporary focal ischemia while anesthetized with either sevoflurane or halothane. Outcome in these animals was compared to that observed in rats maintained unanesthetized during a similar ischemic insult.

METHODS

All rats were anesthetized with halothane and surgically prepared for filament occlusion of the middle cerebral artery. After preparation, one group (Halothane) remained anesthetized with approximately 1.4 MAC halothane. In another group (Sevoflurane), halothane was discontinued and substituted with sevoflurane, which was administered until electroencephalographic burst suppression was evident (approximately 1.4 MAC). The final group (Awake) was allowed to awaken immediately after the onset of ischemia. Middle cerebral artery occlusion persisted for 90 min in all groups. The middle cerebral artery filament then was removed, and a 96-h survival interval was allowed. Neurologic function and infarct volume were determined. Recent evidence indicates that transient mild hyperthermia occurs in awake rats undergoing filament occlusion of the middle cerebral artery. To examine the potential role of mild hyperthermia in this experiment, a second experiment was performed in which rats anesthetized with halothane underwent 90-min focal ischemia, with pericranial temperatures held at either 38.0 degrees C or 39.2 degrees C.

RESULTS

Intraischemic mean arterial pressure was 20-25 mmHg lower in the two anesthetized groups compared with awake animals. Despite this finding, cortical infarct volumes (mean +/- SD; Halothane, 17 +/- 32 mm3; Sevoflurane, 36 +/- 57 mm3; Awake, 115 +/- 104 mm3; Sevoflurane, 36 +/- 57 mm3; Awake, 115 +/- 104 mm3) and subcortical infarct volumes (mean +/- SD; Halothane, 39 +/- 57 mm3; Sevoflurane, 50 +/- 29 mm3; Awake, 88 +/- 46 mm3) were reduced in both groups of anesthetized rats. This reduction correlated with improved neurologic function. The rats in whom the pericranial temperature was maintained at 39.2 degrees C had a larger total infarct volume (218 +/- 81 mm3) and increased neurologic deficits when compared to those in whom the pericranial temperature was maintained at 38.0 degrees C (total infarct volume, 75 +/- 77 mm3).

CONCLUSIONS

Both halothane and sevoflurane substantially reduced damage in this focal ischemia model when compared to outcome resulting from the same insult induced in awake rats. The reduction in intraischemic mean arterial pressure caused by the anesthetics did not seem contributory to outcome. Brain temperature differences among the groups were not defined. Because small differences in pericranial temperature were shown to have major effects on outcome, further work is required to determine if differences in brain temperature explain the observed protective effects of these anesthetics.

A dangerous lack of understanding

In the past, inadequate information on the effects of maternal alcohol consumption on the fetus meant that not enough emphasis was placed on this topic in prenatal and preconceptual teaching. Today, fetal alcohol syndrome is a widely accepted diagnosis in the medical community. Health professionals now stress the importance of abstinence from alcohol during pregnancy, especially during the first trimester. Unfortunately, a surprising number of adults have but a meagre knowledge of the risks. This dangerous lack of understanding represents a failure in health promotion.

Rat MAbs to the product of the c-erbB-2 proto-oncogene for diagnosis and therapy in breast cancer

The product of the c-erbB-2 protooncogene (p185) is a member of the EGF receptor family of transmembrane tyrosine kinases. Amplification of this gene and overexpression of the product has been observed in adenocarcinomas and has been correlated with poor prognosis in patients with breast and ovarian cancer. The very low levels of expression of p185 by normal adult tissues makes the receptor an almost tumor-specific target. We have prepared rat monoclonal antibodies against five distinct epitopes on the external domain of the c-erbB-2 product overexpressed by the breast cancer line BT474. The antibodies bind to the protein core of p185 and stain specifically the membranes in frozen sections of tumors overexpressing the c-erbB-2 product. Three of the antibodies, ICR12 (epitope A), ICR54, and ICR55 (epitope E), also stain the cell membrane in formalin-fixed, paraffin-embedded sections and bind to p185 in Western blots. An investigation of the stability of the antigen-antibody complexes indicates that the majority are not readily internalized by SKOV3 cells growing in vitro. Antibodies ICR12 (IgG2a) and ICR55 (IgG2a), which are directed against separate epitopes on the c-erbB-2 p185, are both of high affinity and immunoreactivity (> 75%) and localize specifically and stably to xenografted breast and ovarian carcinomas growing in athymic mice when labeled with 125I (up to 13% injected dose/g, ICR12 and ICR55) or a range of other radionuclides (up to 20% id/g, ICR12). We conclude that these antibodies may be useful as therapeutic vehicles for targeting radionuclides (imaging and therapy) or enzymes for activating prodrugs (ADEPT).

AMPA receptor competitive antagonism reduces halothane MAC in rats

Various subtypes of receptors have been identified for glutamate, an excitatory neurotransmitter. Previous studies have shown that antagonism of glutamate at the NMDA receptors reduces minimum alveolar concentration (MAC) for volatile anesthetics. NBQX (2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline) is a selective antagonist at the glutamatergic AMPA receptor. The purpose of this experiment was to determine whether AMPA receptor antagonism influences halothane MAC in the rat. Sprague-Dawley rats were anesthetized with halothane in 50% O2/balance N2, tracheally intubated and the lungs were mechanically ventilated. Increasing doses of NBQX were intravenously infused in three groups while the control group was infused with vehicle (D5W). Halothane MAC was then determined by the tail-clamp method. Halothane MAC was log-linearly related to plasma NBQX concentrations (MAC = 0.125 (In plasma concentration NBQX) + 1.035, r2 = 0.77). A maximal 58% reduction of halothane MAC was achieved with an NBQX loading dose of 42 mg/kg followed by a continuous infusion rate of 36 mg x kg-1 x h-1 (control = 1.02 +/- 0.07%; NBQX = 0.43 +/- 0.12%; P < .01). Larger doses of NBQX were not possible because of the poor aqueous solubility of this compound. In a separate experiment, awake rats were randomly assigned to groups based on the dose of NBQX infused. Pa(CO2) and mean arterial pressure were measured at time 0 and at 5 and 30 min after start of NBQX infusion. The infusion was then stopped. Time until recovery of the righting reflex was recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and determinants of caesarean section in Jamaica

The prevalence and determinants of primary caesarean section in Jamaica were estimated from a survey of women aged 14-49 years. Among 2328 women reporting 2395 live hospital births during the period January 1984 to May 1989, the prevalence of caesarean section was 4.1%. Repeat caesarean sections accounted for 1.3% of the hospital births during that period. Of the medical complications studied, prolonged labour and/or cephalopelvic disproportion carried the highest risks of primary caesarean section, followed by breech presentation, maternal diabetes, a high birth-weight baby, maternal hypertension, and a low birth-weight baby. The risk of primary caesarean section increased with maternal age, decreased with parity, was higher for urban than for rural residents, and was higher for births in private versus government hospitals.

Epidural fentanyl does not influence intravenous PCA requirements in the post-caesarean patient

Forty ASA physical status I or II patients scheduled for elective Caesarean delivery were studied to determine the effect of epidural fentanyl on post-Caesarean delivery analgesic requirements as administered by intravenous patient-controlled analgesia (PCA). Following delivery of the infant, under epidural anaesthesia with lidocaine 2% with 1/200,000 epinephrine, patients were randomly assigned to receive either 10 ml of preservative-free normal saline via the epidural catheter or 100 micrograms of fentanyl with 8 ml preservative-free normal saline in a double-blinded fashion. On arrival in the post-anesthesia recovery room (PAR), patients were provided with intravenous PCA meperidine 12.5 mg every eight minutes as needed. Patients were visited at intervals over the next 24 hr to determine if any differences in narcotic requirements, demands for narcotics, or severity of pain were noted. No differences were observed in any values between the groups. It is concluded that a single bolus of epidural fentanyl does not provide an advantage for postoperative pain relief in this patient population.

Cytogenetic analysis of Day-4 embryos from PMSG/hCG-treated prepuberal gilts

Prepuberal gilts were treated with pregnant mare serum gonadotropin (PMSG) to study the effects of its dosage on ovulation rate, fertilization rate after artificial insemination, embryo viability, and rate of development and incidence of chromosome abnormalities in Day-4 embryos. Gilts received 750 IU, 1250 IU or 1500 IU of PMSG, followed 72 h later by 500 IU human chorionic gonadotropin (hCG). Gilts were inseminated 28 to 30 h following the hCG injection, and resulting embryos were collected on Day 4 post ovulation. Ovulation rate was higher in the 1250 IU group than in the 1500 IU group or the 750 IU group. The 1500 IU dose caused excessive stimulation of the ovary, resulting in the occurrence of large (>10mm diameter) unovulated follicles, reduced fertilization rate and low embryo recovery rate. There was no difference in the incidence of chromosome abnormalities among the three groups, although the 1500 IU group had higher embryonic mortality than the two lower dose groups. A dose of 1250 IU PMSG increased ovulation rate above that achieved by 750 IU and, therefore, increased the number of oocytes or embryos available for transfer or for other studies, without sacrificing embryo viability or increasing the incidence of chromosome abnormalities.