Development and validation of Join Clinical Trial Questionnaire (JoinCT)

AIM

Participant recruitment has always been a major challenge in clinical trials. This study aimed to develop and validate the Join Clinical Trial Questionnaire (JoinCT), exploring the willingness to join a clinical trial and associated factors in patients.

METHODS

This questionnaire development study involved four phases: (i) exploring and understanding the subject matter, (ii) questionnaire development, (iii) content validity testing, and lastly, (iv) field-testing of the questionnaire. For the field-testing phase, a cross-sectional self-administered survey of JoinCT was conducted among cancer patients with various socio-demographic backgrounds and medical conditions. Besides content validity, Cronbach's alpha was used to evaluate the internal consistency of domains, and confirmatory factor analysis was used to evaluate the model fit of the JoinCT framework.

RESULTS

A total of 389 respondents participated in the survey. Based on the results obtained from a field data collection phase, JoinCT consisted of four independent variables domains, namely "knowledge", "perception of benefits", "perception of risks", and "confidence". The only dependent variable was the willingness to participate in a clinical trial. The minimum Cronbach's alpha was 0.937, and the model fit for the overall framework of JoinCT is also excellent with Comparative Fit Index (> 0.90), root mean square error approximation (< 0.08), and Standardized Root Mean Square Residual (< 0.08).

CONCLUSIONS

The Join Clinical Trial Questionnaire (JoinCT) was successfully validated with excellent reliability and validity, and a good model fit. The main factors that contribute to willingness to participate in clinical trials are knowledge, perception of benefits, perception of risks, and confidence.

Association of underlying untreated cardiovascular risk factors with mortality and functional outcome in ischaemic stroke patients

OBJECTIVES

The study aimed to determine the prevalence of untreated pharmacologically modifiable cardiovascular risk factors (PMRF) among patients with ischaemic stroke and the association with in-hospital mortality and functional outcome.

METHODS

We analysed the data from ischaemic stroke cases admitted to Sarawak General Hospital between June 2013 and June 2021. We matched the underlying PMRFs with prior medications and categorised them as treated, untreated, or no PMRF. We calculated the prevalence and assessed the association between untreated PMRFs and in-hospital mortality or favourable functional outcome (FFO) at discharge, which was adjusted for age, sex, and other covariates in multivariable models.

RESULTS

We included 1963 patients [65.4% male, 59.8 (SD 13.4) years]; 43.8% who had at least one untreated PMRF had triple the odds of in-hospital mortality [adjusted OR (aOR) 2.86, (95%CI 1.44, 5.70)], whereas 30.2% who had all PMRFs treated showed no significant association. Untreated hypertension [aOR 2.19 (95%CI 1.21, 3.98)], treated [aOR 3.02 (95%CI 1.32, 6.92)], and untreated atrial fibrillation [aOR 1.89 (95%CI 1.18, 3.03)] were significantly associated with more in-hospital death, whereas treated prior stroke was associated with fewer in-hospital death [aOR 0.31 (95%CI 0.11, 0.84)]. Treated diabetes [aOR 0.66 (95%CI 0.49, 0.88)] and untreated prior stroke [aOR 0.53 (95%CI 0.33, 0.83)] were associated with fewer FFO.

CONCLUSION

The high prevalence of untreated underlying PMRFs was significantly associated with poorer outcomes among Malaysian patients with ischaemic stroke in Sarawak. Efforts are needed to promote early screening and treatment of cardiovascular risk factors to reduce the burdens and improve stroke outcomes in this region.

Risk of serious adverse events after the BNT162b2, CoronaVac, and ChAdOx1 vaccines in Malaysia: A self-controlled case series study

BACKGROUND

Rapid deployment of COVID-19 vaccines is challenging for safety surveillance, especially on adverse events of special interest (AESIs) that were not identified during the pre-licensure studies. This study evaluated the risk of hospitalisations for predefined diagnoses among the vaccinated population in Malaysia.

METHODS

Hospital admissions for selected diagnoses between 1 February 2021 and 30 September 2021 were linked to the national COVID-19 immunisation register. We conducted self-controlled case-series study by identifying individuals who received COVID-19 vaccine and diagnosis of thrombocytopenia, venous thromboembolism, myocardial infarction, myocarditis/pericarditis, arrhythmia, stroke, Bell's Palsy, and convulsion/seizure. The incidence of events was assessed in risk period of 21 days postvaccination relative to the control period. We used conditional Poisson regression to calculate the incidence rate ratio (IRR) and 95% confidence interval (CI) with adjustment for calendar period.

RESULTS

There was no increase in the risk for myocarditis/pericarditis, Bell's Palsy, stroke, and myocardial infarction in the 21 days following either dose of BNT162b2, CoronaVac, and ChAdOx1 vaccines. A small increased risk of venous thromboembolism (IRR 1.24; 95% CI 1.02, 1.49), arrhythmia (IRR 1.16, 95% CI 1.07, 1.26), and convulsion/seizure (IRR 1.26; 95% CI 1.07, 1.48) was observed among BNT162b2 recipients. No association between CoronaVac vaccine was found with all events except arrhythmia (IRR 1.15; 95% CI 1.01, 1.30). ChAdOx1 vaccine showed significant association for thrombocytopenia (IRR 2.67; 95% CI 1.21, 5.89) and venous thromboembolism (IRR 2.22; 95% CI 1.17, 4.21).

CONCLUSION

This study shows acceptable safety profiles of COVID-19 vaccines among recipients of BNT162b2, CoronaVac, and ChAdOx1 vaccines. This information can be used together with effectiveness data for risk-benefit analysis of the vaccination program. Further surveillance with more data is required to assess AESIs following COVID-19 vaccination in short- and long-term.

Efficacy of Ivermectin Treatment on Disease Progression Among Adults With Mild to Moderate COVID-19 and Comorbidities: The I-TECH Randomized Clinical Trial

IMPORTANCE

Ivermectin, an inexpensive and widely available antiparasitic drug, is prescribed to treat COVID-19. Evidence-based data to recommend either for or against the use of ivermectin are needed.

OBJECTIVE

To determine the efficacy of ivermectin in preventing progression to severe disease among high-risk patients with COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

The Ivermectin Treatment Efficacy in COVID-19 High-Risk Patients (I-TECH) study was an open-label randomized clinical trial conducted at 20 public hospitals and a COVID-19 quarantine center in Malaysia between May 31 and October 25, 2021. Within the first week of patients' symptom onset, the study enrolled patients 50 years and older with laboratory-confirmed COVID-19, comorbidities, and mild to moderate disease.

INTERVENTIONS

Patients were randomized in a 1:1 ratio to receive either oral ivermectin, 0.4 mg/kg body weight daily for 5 days, plus standard of care (n = 241) or standard of care alone (n = 249). The standard of care consisted of symptomatic therapy and monitoring for signs of early deterioration based on clinical findings, laboratory test results, and chest imaging.

MAIN OUTCOMES AND MEASURES

The primary outcome was the proportion of patients who progressed to severe disease, defined as the hypoxic stage requiring supplemental oxygen to maintain pulse oximetry oxygen saturation of 95% or higher. Secondary outcomes of the trial included the rates of mechanical ventilation, intensive care unit admission, 28-day in-hospital mortality, and adverse events.

RESULTS

Among 490 patients included in the primary analysis (mean [SD] age, 62.5 [8.7] years; 267 women [54.5%]), 52 of 241 patients (21.6%) in the ivermectin group and 43 of 249 patients (17.3%) in the control group progressed to severe disease (relative risk [RR], 1.25; 95% CI, 0.87-1.80; P = .25). For all prespecified secondary outcomes, there were no significant differences between groups. Mechanical ventilation occurred in 4 (1.7%) vs 10 (4.0%) (RR, 0.41; 95% CI, 0.13-1.30; P = .17), intensive care unit admission in 6 (2.4%) vs 8 (3.2%) (RR, 0.78; 95% CI, 0.27-2.20; P = .79), and 28-day in-hospital death in 3 (1.2%) vs 10 (4.0%) (RR, 0.31; 95% CI, 0.09-1.11; P = .09). The most common adverse event reported was diarrhea (14 [5.8%] in the ivermectin group and 4 [1.6%] in the control group).

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial of high-risk patients with mild to moderate COVID-19, ivermectin treatment during early illness did not prevent progression to severe disease. The study findings do not support the use of ivermectin for patients with COVID-19.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04920942.

Implication of current ASE/EACVI left ventricular diastolic function classification in predicting 2-year MACE in asymptomatic patients with diabetes and hypertension

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health Malaysia

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes. Substantial number of patients were classified as indeterminate diastolic function based on the current ASE/EACVI guidelines. The implication of current diastolic function classification in predicting MACE among diabetic patients is not well established.

Purpose

To assess prognostic impact of current guidelines-based diastolic function classification, and determine predictors of 2-year MACE based on individual LVDD parameters.

Methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients had no prior cardiovascular events, had preserved left ventricular (LV) ejection fraction on echocardiography and sinus rhythm on ECG at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LV diastolic function. The 2016 ASE/EACVI guidelines were applied to classify diastolic function. All patients were followed up until 2 years to assess MACE.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 ± 7.45 years; mean duration of type 2 diabetes was 10.5 ± 5.41 years. 80 (72.1%) patients were classified as having normal diastolic function (nDF); 24 (21.6%) patients were classified as indeterminate diastolic function (iDF); 7 patients (6.3%) were classified as LVDD. Patients with LVDD had significantly higher LV mass index (LVMI) (mean 121.72 ± 23.28g/m2 vs 116.62 ± 24.66g/m2 in iDF vs 102.50 ± 22.89g/m2 in nDF, p = 0.003); higher left atrial volume index (LAVI) (mean 41.24 ± 10.28ml/m2 vs 30.55 ± 10.07ml/m2 in iDF vs 25.75 ± 6.30ml/m2 in nDF, p &lt; 0.001); lower lateral e’ velocity (mean 6.35 ± 2.05cm/s vs 7.37 ± 1.73cm/s in iDF vs 8.59 ± 2.13cm/s in nDF, p = 0.003); higher septal E/e’ ratio (mean 14.89 ± 3.29 vs 12.16 ± 3.99 in iDF vs 9.99 ± 2.35 in nDF, p = 0.001); higher average septal-lateral E/e’ ratio (mean 14.22 ± 3.77 vs 11.34 ± 3.74 in iDF vs 9.04 ± 2.10 in nDF, p &lt; 0.001).

Among these 111 patients, 10 patients (9%) reported MACE at 2 years. The risk of 2-year MACE is elevated in both indeterminate diastolic function[hazards ratio (HR) 3.80, p = 0.023] and LVDD (HR 37.78, p = 0.002). BMI (HR 1.25, p = 0.004), and systolic blood pressure (HR 1.07, p &lt; 0.001) were found to be associated with 2-year MACE.

Conclusions

LVDD and indeterminate diastolic function were correlated with increased MACE at 2 years. BMI and systolic blood pressure were predictors of increased risk of MACE at 2 years. Further investigation with larger sample size is warranted.

Implication of Current ASE/EACVI Left Ventricular Diastolic Function Classification in Predicting 2-Year MACE in Asymptomatic Patients with Diabetes and Hypertension

Background

Left ventricular diastolic dysfunction (LVDD) has been shown to be more prevalent in patients with diabetes, and once progress to overt heart failure, carry worse clinical outcomes. Substantial number of patients were classified as indeterminate DF based on the current ASE/EACVI guidelines. The implication of current DF classification in predicting MACE among diabetic patients is not well established.

Purpose

To assess prognostic impact of current guidelines-based DF classification, and determine predictors of 2-year MACE based on individual LVDD parameters.

Methods

A total of 111 patients with diabetes and hypertension who attended diabetic clinic follow-up at the primary healthcare settings were enrolled. All patients had no prior cardiovascular events, had preserved left ventricular (LV) ejection fraction on echocardiography and sinus rhythm on ECG at screening. Echocardiography was performed to obtain parameters of LV dimensions, LV volumes and LVDD. The 2016 ASE/EACVI guidelines were applied to classify DF. All patients were followed up until 2 years to assess MACE.

Results

There were 65 (58.6%) female patients. Mean age was 59.86 (7.45); mean duration of DM was 10.5 (5.41). 80 (72.1%) patients were classified as having normal DF (nDF); 24 (21.6%) patients were classified as indeterminate DF (iDF); 7 patients (6.3%) were classified as LVDD. Patients with LVDD had significantly higher LV mass index (LVMI) (mean 121.72±23.28g/m2 vs 116.62±24.66g/m2 in iDF vs 102.50±22.89g/m2 in nDF); higher left atrial volume index (LAVI) (mean 41.24±10.28ml/m2 vs 30.55±10.07ml/m2 in iDF vs 25.75±6.30ml/m2 in nDF); lower lateral e' velocity (mean 6.35±2.05cm/s vs 7.37±1.73cm/s in iDF vs 8.59±2.13cm/s in nDF); higher septal E/e' ratio (mean 14.89±3.29 vs 12.16±3.99 in iDF vs 9.99±2.35 in nDF); higher average septal-lateral E/e' ratio (mean 14.22±3.77 vs 11.34±3.74 in iDF vs 9.04±2.10 in nDF).

Among these 111 patients, 10 patients (9%) reported MACE at 2 years. The risk of 2-year MACE is elevated in both iDF [odds ratio (OR) 3.80, 95% CI 0.87–16.54, p=0.075] and LVDD [OR 7.60, 95% CI 1.11–52.02, p=0.039]. LVMI (OR 1.027, 95% CI 1.004– 1.051, p=0.023), LAVI (OR 1.092, 95% CI 1.017–1.172), and average septal-lateral E/e' ratio (OR 1.276, 95% CI 1.047–1.557, p=0.016) significantly correlated with 2-year MACE.

Conclusions

LVDD is correlated with increased MACE at 2 years. LVMI, LAVI and average septal-lateral E/e' ratio were predictors of increased risk of MACE at 2 years. Further investigation with larger sample size is warranted.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health Malaysia

COVID-19 testing strategy in response to infection among healthcare workers in a large non-COVID-designated hospital

Sarawak General Hospital, which is the only public access tertiary referral center in Sarawak State for all clinical specialties, was designated a hybrid hospital to treat both COVID-19 and non-COVID-19 patients. During the initial surge of patients admitted with COVID-19, there was also a corresponding increase in health-care workers (HCWs) detected with COVID-19 infection. The latter being isolated, and the large number of staff members that had come into contact with COVID-19 being quarantined from work, placed further strain on the health-care services. The staff mass screening strategy was a policy decision made by the hospital in response to infection among HCWs, and it aimed to reduce in-hospital transmission (particularly among asymptomatic staff), mitigate workforce depletion due to quarantining, and protect the health-care workforce. In this study, we assessed the detection rate of COVID-19 infection from staff mass testing over a five-week period, and described our experience of adopting this surveillance screening strategy alongside ongoing contact tracing and symptomatic screening strategies. Although it was thought that such periodic staff surveillance might be helpful in protecting the health-care workforce within a short period, the long-term implications, especially in settings with limited resources, is significant and therefore explored in this paper. Our findings might provide an evidence-based reference for the future planning of an optimal strategy with the least compromise in care for a larger proportion of non-COVID-19 patients amid efforts against COVID-19 in a large non-COVID-designated hospital with hybrid status.

A hospital-based study on ischaemic stroke characteristics, management, and outcomes in Sarawak: Where do we stand?

BACKGROUND

Located on the Borneo Island, Sarawak is the largest state of Malaysia and has a population distinctive from Peninsular Malaysia. The ischaemic stroke data in Sarawak had not been reported despite the growing number of patients annually. We aimed to investigate patient characteristics, management, and outcomes of ischaemic stroke in Sarawak and benchmark the results with national and international published data.

METHODS

We included ischaemic stroke cases admitted to Sarawak General Hospital between June 2013 and August 2018 from Malaysia National Stroke Registry. We performed descriptive analyses on patient demographics, cardiovascular risk factors, prior medications, smoking status, arrival time, thrombolysis rate, Get With The Guidelines (GWTG)-Stroke measures, and outcomes at discharge. We also numerically compared the results from Sarawak with the published data from selected national and international cohorts.

RESULTS

We analysed 1435 ischaemic stroke cases. The mean age was 60.1±13.2 years old; 64.9% were male; median baseline National Institute of Health Stroke Scale was seven points. Hypertension was the most prevalent risk factor of ischaemic stroke; 12.7% had recurrent stroke; 13.7% were active smokers. The intravenous thrombolysis rate was 18.8%. We achieved 80-90% in three GWTG-Stroke performance measures and 90-98% in four additional quality measures in our ischaemic stroke management. At discharge, 57% had modified Rankin Scale of 0-2; 6.7% died during hospitalisation. When compared with selected national and international data, patients in Sarawak were the youngest; Sarawak had more male and more first-ever stroke. Thrombolysis rate in Sarawak was higher compared with most studies in the comparison. Functional outcome at discharge in Sarawak was better than national cohort but still lagging behind when compared with the developed countries. In-hospital mortality rate in Sarawak was slightly lower than the national data but higher when compared with other countries.

CONCLUSION

Our study described characteristics, management, and outcomes of ischaemic stroke in Sarawak. We achieved high compliance with most of GTWG-Stroke performance and quality indicators. Sarawak had better outcomes than the national results on ischaemic stroke. However, there is still room for improvement when compared with other countries. Actions are needed to reduce the cardiovascular burdens for stroke prevention, enhance healthcare resources for stroke care, and improve intravenous thrombolysis treatment in Sarawak.

Disabling working environments and mental health: A commentary

Employment is a fundamental Social Determinant of Health known to have large impacts on mental health and other health outcomes. Across many countries of the world, people with disabilities are much more likely to be unemployed and looking for work than those without disabilities. The deprivation of employment opportunities is likely to have notable impacts on the health of people with disabilities. In this commentary, we outline the concept of "disabling working environments," which are defined as the range of experiences that affect the likelihood of people with disabilities in obtaining and maintaining quality employment which may then affect a disabled person's health. Disabling working environments are comprised of the following three mutually reinforcing components: 1) Differential selection into work; 2) Selection into certain types of jobs and exposure to poor psychosocial working environments when in employment, and; 3) Differential selection out of work (e.g., leaving employment at an earlier age than those who do not have a disability). We argue that policy and intervention design should consider the life course effects of employment on the mental health of people with disabilities.

Pilot study on functional performance and acceptability of two new synthetic adhesive male condoms (Wondaleaf): a randomized cross-over trial

OBJECTIVES

This study compared the condom failure rate, safety and acceptability of two new synthetic adhesive male condoms, Wondaleaf-Cap® (WLC) and Wondaleaf-On-Man® (WLM), with a marketed latex external condom Durex®-Together (DT).

STUDY DESIGN

We enrolled healthy married, monogamous, heterosexual condom users in a randomized controlled, cross-over, pilot trial in Malaysia. We randomized participants to six groups with different condom use-orders of the experimental WLC and WLM and control latex condom for four episodes for vaginal sex over 1 month for each condom type. We summarized the clinical and non-clinical failure rate, safety and acceptability of each condom type using descriptive statistics. We tested differences in condom failure and acceptability using generalized estimating equations and repeated measure ANOVA respectively.

RESULTS

We screened 75 couples and randomized 50 eligible couples. Two couples withdrew before receiving any condom. The remaining used 576 condoms with 192 uses for each condom variant. Clinical failure rates of WLC, WLM and DT were 1.04%, 0% and 0.52%, respectively. Non-clinical failure rates of WLC, WLM and DT were 2.08%, 3.12% and 1.04%, respectively. Removal was found more painful with Wondaleaf products than the DT. Preferences of participants for WLC, WLM and DT were 33.3%, 29.2% and 25%, respectively. Overall, WLC and DT had greater acceptances among male participants than WLM.

CONCLUSION

Results of this pilot study support that use of synthetic adhesive male condoms is associated with failure rates similar to those seen with existing latex, and with greater acceptability. A larger study to ascertain non-inferiority is underway.

IMPLICATIONS

The availability of synthetic adhesive male condoms may increase the acceptability of condom use. However, removal pain and clinical performance requires further study.

Comparison of effectiveness and time-efficiency between multimedia and conventional counselling on metered-dose inhaler technique education

INTRODUCTION

This study aimed to evaluate whether multimedia counselling (MC) using a touchscreen computer is as effective and time-efficient as conventional counselling (CC) in promoting correct metered-dose inhaler (MDI) technique, with or without the valved holding chamber (VHC).

METHODS

Participants in the MDI-only and MDI-with-VHC groups were randomly assigned to the MC group or CC group. No blinding was imposed. Inhalation technique was assessed using checklists before and after counselling. Time spent on counselling was determined for all participants, while time taken to perfect the technique was determined only for participants who achieved perfect technique within one hour.

RESULTS

The CC group had more elderly participants than the MC group, but the difference was not significant. MDI-only and MDI-with-VHC users showed significant improvement in their inhaler technique after multimedia (44.5 ± 28.0% and 44.1 ± 14.4%, respectively) and conventional counselling (36.8 ± 20.5% and 37.0 ± 14.6%, respectively). No significant difference in MDI technique enhancement was found between the two groups. Although no significant difference was found between the MC and CC groups with regard to the time spent on counselling and the time taken to perfect the technique, the average time spent on counselling was longer for MDI-only users. MDI-only users had 13.5 times the odds of failing to achieve perfect technique compared to MDI-with-VHC users (95% confidence interval 1.50-121.32, p = 0.020).

CONCLUSION

MC and CC significantly improved MDI technique. Both methods showed comparable short-term effectiveness and time-efficiency in MDI technique education. VHC was beneficial, especially for MDI-users with hand-lung coordination problems.

Nafcillin Resistant Staphylococcus Aureus A Possible Community Origin

An increased incidence in nafcillin (semisynthetic penicillins) resistantStaphylococcus aureus(SR-SA), which peaked in January 1980, was noted in Columbus Children's Hospital (CCH), Columbus, Ohio. To investigate the source of this outbreak, we reviewed the susceptibility patterns ofS. aureusstrains isolated at CCH for a 12-month period (July 1979 to June 1980). A total of 773 isolates from 706 patients were investigated with a total of 40 patients colonized or infected with SR-SA, approximately 25% of which were diagnosed in the ambulatory clinics. These patients did not have any apparent previous contact with the inpatient unit or inpatient personnel. Eight nosocomial infections were also uncovered. The first appeared in December 1979. Our studies suggested that some SR-SA isolates may have originated in the community and these organisms may not be exclusive to the hospital environment, as was felt to be the case previously. We also determined that the baseline incidence for our hospital of SR-SA was approximately 2% of total S.aureusisolates. Only 35% of the SR-SA demonstrated resistance to multiple antibiotics. This report indicates that community and nosocomial 5.aureusisolates should be monitored for nafcillin resistance. Vancomycin susceptibility should be tested on all isolates and reported for SR-SA in life-threatening infections.

The role of body-on-a-chip devices in drug and toxicity studies

High-quality, in vitro screening tools are essential in identifying promising compounds during drug development. Tests with currently used cell-based assays provide an indication of a compound's potential therapeutic benefits to the target tissue, but not to the whole body. Data obtained with animal models often cannot be extrapolated to humans. Multicompartment microfluidic-based devices, particularly those that are physical representations of physiologically based pharmacokinetic (PBPK) models, may contribute to improving the drug development process. These scaled-down devices, termed micro cell culture analogs (μCCAs) or body-on-a-chip devices, can simulate multitissue interactions under near-physiological fluid flow conditions and with realistic tissue-to-tissue size ratios. Because the device can be used with both animal and human cells, it can facilitate cross-species extrapolation. Used in conjunction with PBPK models, the devices permit an estimation of effective concentrations that can be used for studies with animal models or predict the human response. The devices also provide a means for relatively high-throughput screening of drug combinations and, when utilized with a patient's tissue sample, an opportunity for individualized medicine. Here we review efforts made toward the development of microfabricated cell culture systems and give examples that demonstrate their potential use in drug development, such as identifying synergistic drug interactions as well as simulating multiorgan metabolic interactions. In addition to their use in drug development, the devices also can be used to estimate the toxicity of chemicals as occupational hazards and environmental contaminants.

Sensory afferent and hypoxia-mediated activation of nucleus tractus solitarius neurons that project to the rostral ventrolateral medulla

The nucleus tractus solitarius (nTS) of the brainstem receives sensory afferent inputs, processes that information, and sends projections to a variety of brain regions responsible for influencing autonomic and respiratory output. The nTS sends direct projections to the rostral ventrolateral medulla (RVLM), an area important for cardiorespiratory reflexes and homeostasis. Since the net reflex effect of nTS processing ultimately depends on the properties of output neurons, we determined the characteristics of these RVLM-projecting nTS neurons using electrophysiological and immunohistochemical techniques. RVLM-projecting nTS neurons were identified by retrograde tracers. Patch clamp analysis in the horizontal brainstem nTS slice demonstrated that RVLM-projecting nTS cells exhibit constant latency solitary tract evoked excitatory postsynaptic currents (EPSCs), suggesting they receive strong monosynaptic contacts from visceral afferents. Three distinct patterns of action potential firing, associated with different underlying potassium currents, were observed in RVLM-projecting cells. Following activation of the chemoreflex in conscious animals by 3 h of acute hypoxia, 11.2+/-1.9% of the RVLM-projecting nTS neurons were activated, as indicated by positive Fos-immunoreactivity. Very few RVLM-projecting nTS cells were catecholaminergic. Taken together, these data suggest that RVLM projecting nTS neurons receive strong monosynaptic inputs from sensory afferents and a subpopulation participates in the chemoreflex pathway.

Three-dimensional integrated microfluidic architectures enabled through electrically switchable nanocapillary array membranes

The extension of microfluidic devices to three dimensions requires innovative methods to interface fluidic layers. Externally controllable interconnects employing nanocapillary array membranes (NCAMs) have been exploited to produce hybrid three-dimensional fluidic architectures capable of performing linked sequential chemical manipulations of great power and utility. Because the solution Debye length, kappa(-1), is of the order of the channel diameter, a, in the nanopores, fluidic transfer is controlled through applied bias, polarity and density of the immobile nanopore surface charge, solution ionic strength and the impedance of the nanopore relative to the microfluidic channels. Analyte transport between vertically separated microchannels can be saturated at two stable transfer levels, corresponding to reverse and forward bias. These NCAM-mediated integrated microfluidic architectures have been used to achieve highly reproducible and tunable injections down to attoliter volumes, sample stacking for preconcentration, preparative analyte band collection from an electrophoretic separation, and an actively-tunable size-dependent transport in hybrid structures with grafted polymers displaying thermally-regulated swelling behavior. The synthetic elaboration of the nanopore interior has also been used to great effect to realize molecular separations of high efficiency. All of these manipulations depend critically on the transport properties of individual nanocapillaries, and the study of transport in single nanopores has recently attracted significant attention. Both computation and experimental studies have utilized single nanopores as test beds to understand the fundamental chemical and physical properties of chemistry and fluid flow at nanometer length scales.

Tracing the source of 3,3'-dichlorobiphenyl found in samples collected in and around Halifax Harbour

3,3'-dichlorobiphenyl (IUPAC No. 11), a chlorobiphenyl (CB) that is not generally analysed in environmental studies of CBs, is found, sometimes at high concentrations, in water, suspended particulate material, biota and sediments from Halifax Harbour, NS, Canada. The results presented demonstrate the need for investigations of non-Aroclor CBs like CB 11. Not only can they have rather elevated environmental concentrations like those reported here for CB 11, but they also can be members of the more toxic non-ortho class of CBs and thus important from a toxicity standpoint. The focus of this paper was to investigate the possible sources of CB 11, a trace constituent of commercial mixtures, but dominant in various environmental compartments of Halifax Harbour.

Population structure of Atlantic salmon (Salmo salarL.): a range-wide perspective from microsatellite DNA variation

Atlantic salmon (n = 1682) from 27 anadromous river populations and two nonanadromous strains ranging from south-central Maine, USA to northern Spain were genotyped at 12 microsatellite DNA loci. This suite of moderate to highly polymorphic loci revealed 266 alleles (5-37/locus) range-wide. Statistically significant allelic and genotypic heterogeneity was observed across loci between all but one pairwise comparison. Significant isolation by distance was found within and between North American and European populations, indicating reduced gene flow at all geographical scales examined. North American Atlantic salmon populations had fewer alleles, fewer unique alleles (though at a higher frequency) and a shallower phylogenetic structure than European Atlantic salmon populations. We believe these characteristics result from the differing glacial histories of the two continents, as the North American range of Atlantic salmon was glaciated more recently and more uniformly than the European range. Genotypic assignment tests based on maximum-likelihood provided 100% correct classification to continent of origin and averaged nearly 83% correct classification to province of origin across continents. This multilocus method, which may be enhanced with additional polymorphic loci, provides fishery managers the highest degree of correct assignment to management unit of any technique currently available.

Intraspecific phylogeography of Lasmigona subviridis (Bivalvia: Unionidae): conservation implications of range discontinuity

A nucleotide sequence analysis of the first internal transcribed spacer region (ITS-1) between the 5.8S and 18S ribosomal DNA genes (640 bp) and cytochrome c oxidase subunit I (COI) of mitochondrial DNA (mtDNA) (576 bp) was conducted for the freshwater bivalve Lasmigona subviridis and three congeners to determine the utility of these regions in identifying phylogeographic and phylogenetic structure. Sequence analysis of the ITS-1 region indicated a zone of discontinuity in the genetic population structure between a group of L. subviridis populations inhabiting the Susquehanna and Potomac Rivers and more southern populations. Moreover, haplotype patterns resulting from variation in the COI region suggested an absence of gene exchange between tributaries within two different river drainages, as well as between adjacent rivers systems. The authors recommend that the northern and southern populations, which are reproductively isolated and constitute evolutionarily significant lineages, be managed as separate conservation units. Results from the COI region suggest that, in some cases, unionid relocations should be avoided between tributaries of the same drainage because these populations may have been reproductively isolated for thousands of generations. Therefore, unionid bivalves distributed among discontinuous habitats (e.g. Atlantic slope drainages) potentially should be considered evolutionarily distinct. The DNA sequence divergences observed in the nuclear and mtDNA regions among the Lasmigona species were congruent, although the level of divergence in the COI region was up to three times greater. The genus Lasmigona, as represented by the four species surveyed in this study, may not be monophyletic.

Treating urinary incontinence in the elderly population: accepting the challenge

Health care professionals who choose to treat the elderly have a responsibility to be knowledgeable about incontinence. The elderly present challenging and complex problems that may require a collaborative approach from a dedicated team, to include family members, home health nurses, continence nurses, physical therapists, as well as primary care physicians, geriatricians, urologists, and gynecologists. The elderly patient should be reminded that they are a member of that team and their commitment and participation will facilitate successful outcomes.

Estimating analytical variances in measurement of polycyclic aromatic hydrocarbons and application to monitoring contaminants in American lobster (Homarus americanus)

A method is presented for estimating replicate polycyclic aromatic hydrocarbon (PAH) concentrations in American lobster (Homarus americanus) digestive gland tissue based on recoveries of added perdeuterated surrogates from a single satisfactory analysis. PAH concentrations demonstrated a large interanimal variance, even in specimens captured at the same time in the same place. Principal component analysis showed that the variability of the total system of biological variables (carapace length, lobster weight, and digestive gland weight) could be adequately summarized by the first principal component alone in each data set. Ranks provide ordered classification of individuals, allowing data analysis by statistical methods for continuous variables (i.e., analysis of variance). PAH concentrations in individual lobsters were generally highly sensitive to animal size, sex, and fishing area. Efficient monitoring would result from analyzing individual animals of a single sex from a study area, using as small a geographical study area as possible, measuring a single biological variable, and using individual specimens of as narrow a size range as possible.

Rapid screening of fish tissue for polychlorinated dibenzo-p-dioxins and dibenzofurans

A rapid, simple method for screening polychlorinated dibenzo-p-dioxin and dibenzofuran classes in shellfish tissue at pg g-1 wet mass concentrations is described. The method does not require a clean room facility and is based on saponification followed by extraction into hexane, clean-up using gel-permeation chromatography and sulfuric acid treatment, and measurement using capillary gas chromatography-low resolution mass spectrometry with selected ion monitoring. Selected ion monitoring using multiple ions eliminates interferences not removed by clean-up or chromatography. The detector response factor is constant for isomers within a class, e.g., tetrachlorodibenzo-p-dioxin isomers gave a mean response of 0.977 +/- 0.075 area counts fg-1, but varied significantly between classes. Thus one isomer serves as a 'standard' for all members of its class. Recoveries of added polychlorinated dibenzo-p-dioxins and dibenzofurans (20-500 pg g-1 wet mass) averaged 95.6 +/- 6.9 and 99.0 +/- 5.7%, respectively. The limits of detection (five times the noise level) are 20 pg g-1 tetrachlorodibenzo-p-dioxins and dibenzofurans, 20 pg g-1 pentachlorodibenzo-p-dioxins and dibenzofurans, 40 pg g-1 hexachlorodibenzo-p-dioxins and dibenzofurans, 40 pg g-1 heptachlorodibenzo-p-dioxins and dibenzofurans, and 100 pg g-1 octachlorodibenzo-p-dioxin and dibenzofuran. Above the limits of detection, the method gave results for polychlorinated dibenzo-p-dioxin and dibenzofuran classes in shellfish tissue comparable to those obtained by gas chromatography-high resolution mass spectrometry.

The influence of early nutrition and environmental rearing on brain growth and behaviour

Preweaning malnutrition permanently reduced brain size and cellular content but in spite of changes in the adrenocotical stress response no learning deficit was observed. Differential rearing environments did not influence the effects of malnutrition.

Hormonal regulation of fetal brain cell proliferation: presence in serum of a trophin responsive to pituitary growth hormone stimulation

Previous studies led us to hypothesize that brain growth was regulated by a growth hormone-dependent brain trophin. An in vitro bioassay system to assess this proposal was developed. Serum was shown to stimulate the uptake of tritiated thymidine into fetal brain cell DNA. This action could not be attributed to any nutrient contribution but was due to a non-dialyzable, heat-stable serum growth factor. The levels of the growth factor in serum were reduced after pituitary removal. When added in physiological concentration, growth hormone, prolactin, placental lactogen, insulin, nerve growth factor, thyroid and steroid hormones failed to stimulate the action of serum or to act synergistically with a serum component to stimulate DNA synthesis. Thyroxine, estradiol-17beta, and corticosterone inhibited serum activity. Administration of growth hormone to hypophysectomized rats restored serum levels to normal demonstrating that the serum growth factors was a mediating trophin responsive to pituitary growth hormone stimulation. The relationship of the brain trophin to other serum growth factors and its specificity of action remain to be defined. The present findings were in accordance with in vivo studies of hormonal influence on brain growth and support the proposal that fetal brain cell proliferation is stimulated by a serum trophin responsive to pituitary growth hormone.

The influence of protein restriction imposed at various stages of pregnancy on fetal and placental development

The effect of protein restriction on fetal and placental growth was investigated. Pregnant rats were maintained on an isocaloric diet containing either 23% or 5% protein. The diet was imposed either from days 1-21 of gestation or from days 7-21 of gestation. Fetal body development was assessed. Fetal brain and placental growth were determined by both analysis of organ DNA, RNA and protein and differential radiochemical labelling procedures. Maternal protein restriction inhibited fetal growth. Brain weight was reduced due to a significant decrease in cellular content. Brain cell size was significantly increased and may have accounted for the reduction in cell concentration. Placental growth was similarly impaired. These data demonstrate impaired fetal and placental growth following decreased maternal dietary protein intake. Severity of growth retardation increased with the duration of malnutrition. The results also suggest that malnutrition may affect the rate of development, causing premature cessation of cell division and early cell differentiation.