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Biomedical subjects

S Chambers

Publications and source records attributed to S Chambers.

At least 37 records · Page 2Linked to original sources
PubMed1998

Demonstration of a method to characterize and develop airway access devices for total liquid ventilation.

Devices are being developed to carry out perfluorocarbon total liquid ventilation (TLV) in adult-sized animals or patients. A limiting factor in the clinical application of TLV lies in the ability to administer adequate tidal volumes of oxygenated perfluorocarbon through airway access devices. A single number, the M-number, is demonstrated in this paper as a systematic method for ranking the flow characteristics of currently available airway access devices, such as endotracheal or tracheostomy tubes, and for designing new airway access devices exclusively for TLV. The M-number of several commonly used endotracheal and tracheostomy tubes is determined as a demonstration of the use of the M-number. Two nomograms are presented based on the M-number, and a description for their use in the clinical and laboratory settings is given.

Adult↗
PubMed1998

Shigella outbreak in a school associated with eating canteen food and person to person spread.

In June 1993 an outbreak of Shigella sonnei infection at a primary school in south east England affected 42% of 327 pupils and staff. Attack rates of diarrhoea and fever were 33% for children aged 4 to 8 years, and 8% for those aged 8 to 12 years (p < 0.00001). Illness was associated with eating canteen food (relative risk 5.9; 95% confidence interval 3.4, -10.3). All strains examined were S. sonnei phage type 3, with the same antibiogram (ttSTSS), and were indistinguishable using colicin typing and biotyping (colicin type 9, E8) and pulse field gel electrophoresis. Molecular epidemiology suggested but could not confirm that the outbreak strain was introduced into the school population from the community.

Adult↗
PubMed1997

Helicobacter pylori eradication using a 7-day regimen of low-dose clarithromycin, lansoprazole and amoxycillin.

AIM: To evaluate the efficacy of a 7-day regimen of clarithromycin 250 mg b.d., amoxycillin 1 g b.d., and lansoprazole 30 mg b.d. as a treatment for Helicobacter pylori infection. METHODS: H. pylori status of dyspeptic patients was assessed by 13C-urea breath test and at endoscopy by histology, culture and rapid urease testing of gastric biopsies. Fifty-one H. pylori-positive patients were treated with the above regimen. H. pylori status was reassessed by 13C-urea breath test not less than 28 days after completing treatment. Adverse events and compliance were evaluated. RESULTS: On an intention-to-treat basis. H. pylori infection was cured in 77% (95% CI: 65-88%) of patients. Minor side-effects including diarrhoea, nausea and taste disturbance were reported by 64% of patients. Ninety-five per cent of patients consumed > 95% of tablets. Metronidazole resistance was 29% but all cultures were sensitive to amoxycillin and clarithromycin. CONCLUSION: This 7-day treatment with low-dose clarithromycin was moderately effective in curing H. pylori infection. Although compliance was excellent, there was a high frequency of minor adverse events.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1996

The RpoN-box motif of the RNA polymerase sigma factor sigma N plays a role in promoter recognition.

The RNA polymerase sigma factor sigma N (sigma 54) is characterized by the presence, near the C-terminal end of the protein, of a highly conserved sequence of 10 amino acids (ARRTVAKYRE) that has been termed the RpoN box. In order to examine the function of this motif, which is predicted to adopt an alpha-helical structure, we have isolated a number of mutations that alter residues within the box and examined the properties of the sigma N derivatives encoded by them. Certain mutations that alter charged and potentially exposed residues within the motif result in transcriptionally inactive proteins with impaired promoter recognition but no impairment in core RNA polymerase binding. We therefore suggest that the RpoN box could play a direct or indirect role in recognition of the -24, -12 promoter consensus that is characteristic of sigma N-dependent genes.

Amino Acid Sequence↗
PubMed1996

A seven-day Helicobacter pylori treatment regimen using clarithromycin, omeprazole and tripotassium dicitrato bismuthate.

AIM: To evaluate clarithromycin 500 mg t.d.s., tripotassium dicitrato bismuthate 240 mg b.d. and omeprazole 20 mg b.d. for 7 days as a Helicobacter pylori treatment regimen. METHODS: The H. pylori status of dyspeptic patients undergoing endoscopy was assessed by histology, culture and rapid urease testing of biopsies and by 13C-urea breath test. Fifty patients who were H. pylori-positive were treated with the above treatment regimen for 7 days. Those patients with active duodenal ulcers present at endoscopy were given omeprazole 20 mg nocte for a further 21 days. Not less than 28 days after completing treatment, all tests were repeated to reassess H. pylori status. Bacterial sensitivity of H. pylori cultures was determined and patients recorded any side-effects. RESULTS: On an intention-to-treat basis, H. pylori infection was cured in 90% (95% CI: 78-96%) of patients. Taste disturbance was experienced by 35% patients. Compliance was excellent, with 96% patients taking more than 95% of tablets. Metronidazole resistance was 41% but all cultures were sensitive to clarithromycin. CONCLUSIONS: This 7-day treatment achieved a high level of cure of H. pylori infection with relatively minor side-effects. It may have a role to play, particularly where there is a high level of metronidazole resistance.

Adult↗
PubMed1996

Rollerblading injuries in young people.

OBJECTIVE: To study injuries in young people associated with the use of rollerblades, draw comparisons with skateboarding and rollerskating injuries, and suggest strategies for injury prevention. METHODOLOGY: Injuries associated with the use of rollerblades, skateboards and rollerskates in young people aged < or = 14 years recorded on the Victorian Injury Surveillance System database since its inception in 1989 were examined to identify secular trends. All injuries associated with these pastimes recorded on the database by three sentinel hospitals during a 1 year period were examined in detail. Medical notes were perused to verify features of the event and obtain further information. A semi-structured telephone interview of a sample of 10-14 year old rollerbladers, the most commonly injured age-group, was carried out to obtain more specific information. RESULTS: There has been a marked increase in the absolute numbers of injuries associated with the use of rollerblades since 1989. In 1992, they were most common in the 10-14 year age group, which sustained 59% of all injuries; 47% of injuries were fractures of the forearm and wrist. Of a sample of 33 of those injured in the 10-14 year age group, 10 (30%) had been using rollerblades for the first time. There is some evidence to suggest a concomitant fall in skateboarding injuries. CONCLUSIONS: Injury surveillance data collected in Melbourne suggest an increasingly important contribution by rollerblading to the pattern of injury seen in young people. Preventive strategies require further evaluation but could include learning basic techniques in a controlled setting, separation from road traffic and the wearing of helmets and wrist, elbow and knee guards.

Adolescent↗
PubMed1996

Clinical and ultrasound prediction of macrosomia in diabetic pregnancy.

OBJECTIVE: To study prospectively the prediction power, at different gestations, of clinical and ultrasound measurements for fetal size in diabetic pregnancy. SETTING: A large combined obstetric diabetic clinic in a teaching hospital. PARTICIPANTS: One hundred and eighty-one pregnancies in which women had scans at least two of three specific time points and who were delivered of singletons after 34 weeks: 73% were pre-gestational insulin-dependent diabetics, the others were pre-gestational White class A or gestational diabetics. INTERVENTIONS: Clinical estimates of fundal height and fetal size and ultrasound estimates of abdominal circumference and head circumference were routinely carried out at gestational ages of 28, 34 and 38 weeks or before delivery. MAIN OUTCOME MEASURES: Standardised birthweight, corrected for gestation and parity. The relation with clinical and ultrasound measurements was investigated using multiple linear regression and the capability of the measurements to predict macrosomic births (> 95th centile of normals) using receiver-operator characteristic curves. RESULTS: All measurements are poor predictors of eventual standardised birthweight. Prediction improves with closeness to delivery. Prediction is significantly improved by adding ultrasound to clinical information, but at 34 weeks or later this only contributes 8% of the variance. There is no difference in the prediction power for macrosomia between clinical and ultrasound measurements. CONCLUSIONS: Even regular serial scanning and clinical examination will not always diagnose the macrosomic fetus in diabetic pregnancy. In our hands, clinical examination is as predictive as ultrasound measurements. Ultrasound does add to clinical prediction power but only to a small extent. Ultrasound should be used in a selected way, as defined by clinical findings, and with recognition and understanding of the errors and biases involved.

Birth Weight↗
PubMed1995

Evidence for 5-hydroxytryptamine1A receptor involvement in the control of prolactin secretion in man.

The effects of pindolol pretreatment (2 days) on prolactin and cortisol responses to a single dose of (+)-fenfluramine (30 mg po) were examined in nine healthy male volunteers. Pindolol pretreatment attenuated the (+)-fenfluramine-induced increase in prolactin concentrations but failed to affect the (+)-fenfluramine-induced cortisol increase. These data provide evidence in support of 5-HT1A receptor involvement in the regulation of prolactin secretion but question its importance in the regulation of cortisol secretion in man.

Adult↗
PubMed1995

The use of anti-D to improve post-transfusion platelet response: a randomized trial.

Patients undergoing induction chemotherapy for acute leukaemia often become refractory to platelet transfusions. Increased clearance of transfused platelets due to alloimmune destruction has been identified as one of the primary mechanisms contributing to this refractory state. We performed a double-blind randomized trial to determine whether the administration of anti-D to Rh-positive individuals could prevent the refractory state and improve post-transfusion platelet response. Rh-positive patients with acute leukaemia undergoing induction chemotherapy and requiring platelet transfusions were allocated to weekly intravenous anti-D (20 micrograms/kg) or placebo. Platelets and red cell concentrates were administered according to standardized transfusion guidelines. Outcome measures included platelet transfusion utilization, red cell utilization, platelet recovery 18-24 h post-infusion, and the percentage of patients refractory to platelet transfusion. There were 43 patients studied: 21 received anti-D and 22 saline placebo. The mean number of platelet concentrates required per day of observation was 0.59 (SD 0.22) in the anti-D group and 0.61 (SD 0.22) in the placebo group, P = 0.86. No difference was detected between groups in terms of platelet recovery post-infusion, refractoriness to platelet transfusion or frequency of infection (P = 0.97). Red cell concentrate utilization was significantly increased in the anti-D group compared to the placebo group, 0.58 units per day versus 0.37 units per day respectively, P = 0.005. We conclude that the use of anti-D did not improve post-transfusion platelet response in Rh positive patients with acute leukaemia, but did result in an increased need for red cell transfusion.

Acute Disease↗
PubMed1995

Seroprevalence of Helicobacter pylori in residents of a hospital for people with severe learning difficulties.

OBJECTIVE: To assess the seroprevalence of Helicobacter pylori among the residents of a hospital for people with severe learning difficulties. DESIGN: Retrospective analysis of stored sera from the hospital residents and control sera from the local, non-residential population. METHODS: H. pylori immunoglobulin G antibody was measured in 424 hospital residents using an enzyme-linked immunosorbent assay, taking an antibody level of > 10 units/ml as evidence of H. pylori infection. The results were compared with 267 age- and sex-matched controls. RESULTS: Seropositivity rates were significantly higher in the hospital residents than in controls for all ages. This was most marked among those under 40 years of age (87 versus 24% H. pylori-positive for residents and controls, respectively; P < 0.001). The overall seropositivity rates were 87 and 43% for residents and controls, respectively (P < 0.001). CONCLUSIONS: This English study of H. pylori seroprevalence in an institutionalized population is the largest to date and confirms the very high seropositivity rates found by previous studies in Australia. Our findings may have significance for the future health of these patients and for the possible modes of transmission of H. pylori.

Adolescent↗
PubMed1994

A case control study to determine risk factors for campylobacter infection in Christchurch in the summer of 1992-3.

AIM: This study was designed to determine the risk factors for acquiring campylobacter infection in Christchurch in the summer of 1992/3. METHODS: A case control study was conducted of 100 cases and controls from urban areas matched for age and sex. Cases and controls were interviewed by telephone using a questionnaire and results analysed using the Epi Info statistical computer programme. RESULTS: Eighty one percent of both cases and controls had recently consumed poultry. Eating poultry at a friends house (OR = 3.18, CI 1.0, 10.73, p = 0.03), at a barbecue (OR = 3.00, CI 0.99, 9.34, p = 0.03) or eating undercooked chicken (OR = 4.94, CI 1.03, 23.62, p = 0.05) was a risk whereas eating at home was protective (OR = 0.36, CI 0.14, 0.9, p = 0.02). Other factors associated with increased risk were drinking water from a nonurban supply (OR = 2.7, CI 0.89, 8.33, p = 0.09) or consumption of chicken bought fresh (OR = 1.8, CI 0.85, 3.82, p = 0.10). CONCLUSION: Poorly cooked or handled chicken is a significant source of human campylobacter infection. Morbidity may be reduced by increased public awareness and improvement of cooking practices.

Adolescent↗
PubMed1994

Atopic children with cystic fibrosis have increased urinary leukotriene E4 concentrations and more severe pulmonary disease.

BACKGROUND: We investigated the hypothesis that cysteinyl leukotriene (LT) production is altered in atopic patients with cystic fibrosis (CF). METHODS: Urinary LTE4 was measured in two groups of children with CF: atopic (ACF group, n = 22) and nonatopic (NACF group, n = 13); and in two groups of unaffected children, those with atopic asthma (AA group, n = 11) and nonatopic normal control subjects (NN group, n = 12). RESULTS: Atopic groups excreted significantly more urinary LTE4 (geometric means [95% confidence intervals] in picomoles per millimole creatinine), ACF group: 104 (73-147) and AA group: 195 (136-282) compared with NACF group: 19 (9-39) and NN group: 27 (15-48). The ACF group had significantly more airflow obstruction than the NACF group, with forced expiratory volume in 1 second (percent predicted, mean +/- SD) in ACF: 58 +/- 21 versus NACF: 81 +/- 23, and forced vital capacity (percent predicted, mean +/- SD) 72 +/- 17 versus 87 +/- 23, respectively. There were significant correlations between the degree of airflow obstruction, bronchodilator responsiveness, and urinary LTE4 concentration within the entire CF group. We used multiple regression analysis to assess the respective influence of age, atopy, sensitization to Aspergillus fumigatus, and colonization with Pseudomonas aeruginosa on urinary LTE4 concentration. The atopic state was the only significant variable associated with urinary LTE4 production in subjects with CF. CONCLUSIONS: The similarities in urinary LTE4 between ACF and AA groups suggest that the atopic state is the prime determinant of urinary LTE4 excretion. Enhanced cysteinyl LT production associated with atopy in CF may increase the severity of pulmonary disease.

Adolescent↗
PubMed1994

Clinical effects of buspirone on intractable self-injury in adults with mental retardation.

OBJECTIVE: The efficacy of buspirone in controlling self-injurious behavior was examined in five individuals with mental retardation. Buspirone was used alone in two individuals and as an adjunct to thioridazine in the other three. METHOD: Standard behavioral observation methods were used to collect data on the number of self-injurious responses of the individuals during baseline and several doses of buspirone in an open trial. RESULTS: When compared with baseline levels, all five individuals showed some response to buspirone, with reductions in self-injury ranging from 13% to 72%, depending on the dose. The most effective dose of buspirone was 30 mg/day for three individuals and 52.5 mg/day for the other two. These individuals were maintained for 6 to 33 weeks on their most effective dose. Coexistent symptoms of anxiety did not predict a favorable response to buspirone therapy. CONCLUSIONS: Buspirone showed a mixed but generally favorable response in controlling intractable self-injury in this and four previous studies reporting similar cases. However, the drug should not be endorsed as a proved treatment for self-injury until similar results have been obtained from well-controlled studies of its efficacy.

Adult↗
PubMed1993

To each according to need: a community-based approach to allocating health care resources.

OBJECTIVE: To develop a method of allocating publicly funded health care resources among communities according to their relative levels of need for health care independent of their current patterns of use. DESIGN: For each health care program population mean levels of resource allocation were calculated and were adjusted for age and sex to produce a national age- and sex-adjusted share of program resources. Indices of relative need for health care (for most programs the standardized mortality ratio) were derived from existing data on aspects of illness and death and were then used to weight the age- and sex-adjusted shares for between-community differences in health risks and health care needs. SETTING: The populations of the 49 counties in Ontario were used as the communities among which resources were allocated. Health care expenditures in 1988-89 by the Ontario Ministry of Health were used as the "budget." MAIN RESULTS: Age- and sex-adjusted resource allocations weighted for between-community differences in health care needs differed from allocations based on population size, in certain cases by up to 100%. CONCLUSION: Existing data can be used to propose allocations of health care resources that relate to relative levels of need for care across communities.

Canada↗
PubMed1992

Demonstration of the distribution of coxsackie virus RNA in neonatal mice by non-isotopic in situ hybridization.

A simple method for the demonstration of Coxsackie virus RNA by in situ hybridization is described. Oligonucleotides complimentary to conserved sequences of Coxsackie B genome were synthesised and labelled with digoxigenin using commercially available reagents. In addition to detecting all five Coxsackie B strains examined, six strains of Coxsackie A were also demonstrated by these probes. Using one of the oligonucleotides separately it was possible to distinguish Coxsackie A strains from the strains of Coxsackie B virus examined. This study demonstrates the presence of viral RNA in mice tissues showing morphological evidence of damage, confirming the suspected tropisms of these viruses. The method described is directly applicable to the study of the presence of these viruses in human tissue from diseases where a viral aetiology is suspected.

Animals↗