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Biomedical subjects

S Williams

Publications and source records attributed to S Williams.

At least 235 records · Page 13Linked to original sources
PubMed1999

Breast cancer in Maori and non-Maori women.

BACKGROUND: Breast cancer is more common in Maori than in non-Maori women under the age of 40 years and is equally common in older women, despite Maori being generally of lower socioeconomic status and having had a higher fertility rate than non-Maori. METHODS: Data from a nationwide population-based case-control study of breast cancer in New Zealand women aged 25-54 years were used to compare the age-adjusted distribution of reproductive and other risk factors for breast cancer in self-identified Maori and non-Maori women from the control group. Separate analyses also were carried out for women aged 25-39 years and for those aged 40-54 years. The risk of breast cancer according to the proportion of Maori ancestry was estimated using multiple logistic regression simultaneously adjusting for several risk factors. RESULTS: Significant differences were found between self-identified Maori and non-Maori women in the age-adjusted frequencies for education level, socioeconomic status, age at first full-term pregnancy, parity, and duration of breastfeeding; the profile in all instances suggesting a lower risk of breast cancer for Maori than for non-Maori. There were no significant differences with respect to age at menarche, surgery for benign breast disease or a family history of breast cancer. Significantly more Maori than non-Maori were in the highest quartile of recent body mass index. Women self-identified as Maori has an approximately twofold higher risk of breast cancer than non-Maori women. CONCLUSIONS: Maori have high rates of breast cancer despite having a more favourable profile than non-Maori for most identified risk factors.

Adult↗
PubMed1999

Patient classification systems, Part 2: The third generation.

In Part 1 (July/August 1999), the authors reviewed the evolution of patient classification systems over four generations of progress, discussed issues of system credibility, and presented a third-generation patient classification system (3PCS) to address the shortcomings of current systems. In this article, an actual implementation of a 3PCS is presented by the authors in collaboration with system users. The development, implementation, and evaluation of the 3PCS, as well as the overall advantages, are discussed. Finally, the authors share lessons learned and thoughts for the future.

Holistic Health↗
PubMed1999

Determining the angle of screw placement for internal fixation of calcaneal fractures.

OBJECTIVE: This study was designed to determine the angle off the perpendicular to the lateral calcaneal wall at which a screw would need to be angled to avoid entering the subtalar joint medially. It also determined the distance inferior to the articular surface at which a screw would need to be placed to avoid that penetration if the screw was placed perpendicular to the lateral calcaneal wall. METHODS: Eight specimens were dissected and the calcaneus was removed. The measurements were taken from portions of the subtalar joint. RESULTS: To avoid medial penetration, a screw at the anterior portion of the posterior facet would need to be angled 5 degrees plantar medially or placed 1.5 millimeters below the edge of the articular surface. In the midportion, placements are 20 degrees or 10 millimeters; posteriorly, placements are 32 degrees or 15 millimeters. CONCLUSION: This study shows that using a lateral approach, it is possible to position internal fixation screws without disrupting the articular surfaces of the medial subtalar joint.

Ankle Injuries↗
PubMed1999

Tobacco smoking among fourth form school students in Wellington, New Zealand, 1991-97.

OBJECTIVE: To investigate trends in smoking and associated demographic factors among fourth form (14-15 years) school students. METHOD: In 1991, all 35 secondary schools in Wellington, New Zealand, were invited to participate; 15 took part. Smoking behaviours were assessed biennially by self-report. Trends were examined among 5,834 students, using multilevel regression. RESULTS: When adjusted for sex, ethnicity and their interaction, the baseline (1991) prevalence of smoking within the past month was 18% (95% CI 10-29) rising to 28% (95% CI 15-46) in 1997. The comparable baseline prevalence of daily smoking was 8% (95% CI 3-21) rising to 15% (95% CI 4-40) in 1997. Smoking was more common among girls than boys and most common among Maori girls, for whom the adjusted odds of current and daily smoking were, respectively, 3.40 times (95% CI 2.56-4.52) and 5.00 times (95% CI 3.64-6.87) those of Europeans. School socio-economic status and sex composition added to the explanatory power of the model for daily smoking, but had negligible effect on the odds ratios for sex and ethnic group. CONCLUSIONS AND IMPLICATIONS: The suggested rise in the prevalence of smoking has implications for future adult smoking rates and health costs. Under-representation of socio-economically disadvantaged schools may have produced conservative estimates. The increased odds of smoking among girls and Maori confirm the need to develop interventions appropriate for these groups.

Adolescent↗
PubMed1999

Trauma to primary teeth of South African pre-school children.

A clinical survey of 1466 children of typical South African communities showed a prevalence rate of primary tooth trauma of 15%. Trauma was least common at age 1-2 years (10.7%) and most common at 4-5 years (20.6%). The commonest trauma seen was fracture of enamel only (71.8%) followed by fracture of dentine (11.2%), tooth loss (8.2%) and discolouration without other sign of injury (5.6%).

Age Distribution↗
PubMed1999

Characterization of an immunogenic glycocalyx on the surfaces of Cryptosporidium parvum oocysts and sporozoites.

Ruthenium red staining of Cryptosporidium parvum oocysts revealed the presence of a carbohydrate matrix on their outer bilayers that is characteristic of a glycocalyx. Surface labeling of intact oocysts identified material of high molecular weight (>10(6)) that reacted positively with sera from cryptosporidium-infected patients and with immunoglobulin A monoclonal antibodies.

Animals↗
PubMed1999

Attitudes towards general practice and primary care: a survey of senior house officers in accident and emergency.

OBJECTIVES: The attitudes and knowledge of hospital based staff about the capabilities of general practice may be important obstacles to continuity of care and the quality of communication at the primary-secondary care interface. However, little research has sought to investigate such factors or how they change over time. The study aims to assess how senior house officers (SHOs) in accident and emergency (A&E) departments perceive general practice, and to test how attitudes change during their six months' tenure. METHODS: Questionnaires were sent to all A&E SHOs working in the 27 A&E departments in South Thames region. At the end of the first month and at the end of the sixth months SHOs were asked to respond using 100 mm visual analogue scales to statements about the quality of general practitioner (GP) services in their area and their attitudes towards treating primary care patients in A&E. RESULTS: After sending reminders, 135 (79%) SHOs responded to the questionnaire at the end of the first month, and 115 (67%) responded to the questionnaire at the end of the sixth month; 104 (61%) responded to both. Statements relating to GP accessibility within and outside normal working hours, perceptions of patients' satisfaction with GP services, GPs' effectiveness in educating patients about use of services, and the frustrations and lack of reward of treating primary care patients scored most negatively. The overall trend was for attitudes to become more negative during SHOs' period of employment in A&E, particularly for those intent on hospital specialist careers or those working within London hospitals. CONCLUSIONS: The findings indicate the extent to which attitudes become more entrenched over time. This may lead to care that is more hospital focused. These issues need to be addressed if quality improvement is to occur across the A&E-primary care interface.

Attitude of Health Personnel↗
PubMed1999

Training and supervision needs and experience: a longitudinal, cross-sectional survey of accident and emergency department senior house officers.

The aim of this study was to investigate senior house officers' (SHOs) perceptions about their training needs, satisfaction with teaching and supervision, and the relationship this has with psychological distress levels. All 171 SHOs employed within 27 accident and emergency (A&E) departments in the South Thames region were sent questionnaires at the start of their attachments in A&E, at the end of months four and six. The questionnaires asked SHOs to rate on visual analogue scales their perceived need for further training for 23 clinical and practical activities relevant to A&E practice. At the end of the fourth month SHOs were asked to indicate who had provided them with the most valuable teaching and supervision, indicate their satisfaction levels with training received, and suggest ways to improve teaching and supervision. SHOs' psychological distress levels were measured in all three questionnaires. Overall, satisfaction with supervision and training was mixed. SHOs perceived greatest need for further training in areas encountered less frequently in A&E. Registrars were the most valued providers of supervision and teaching. Increased numbers of middle grade staff and protected study time were suggested as ways to improve supervision and teaching. SHOs with higher scores for training need at the end of their attachment in A&E expressed significantly less satisfaction with training and higher psychological distress levels. The variation between SHOs' perceptions of training needs indicates the importance of tailoring training and supervision to individual requirements.

Cross-Sectional Studies↗
PubMed1999

Undergraduate students' misconceptions about respiratory physiology.

Approximately 700 undergraduates studying physiology at community colleges, a liberal arts college, and universities were surveyed to determine the prevalence of our misconceptions about respiratory phenomena. A misconception about the changes in breathing frequency and tidal volume (physiological variables whose changes can be directly sensed) that result in increased minute ventilation was found to be present in this population with comparable prevalence (approximately 60%) to that seen in a previous study. Three other misconceptions involving phenomena that cannot be experienced directly and therefore were most likely learned in some educational setting were found to be of varying prevalence. Nearly 90% of the students exhibited a misconception about the relationship between arterial oxygen partial pressure and hemoglobin saturation. Sixty-six percent of the students believed that increasing alveolar oxygen partial pressure leads to a decrease in alveolar carbon dioxide partial pressure. Nearly 33% of the population misunderstood the relationship between metabolism and ventilation. The possible origins of these respiratory misconceptions are discussed and suggestions for how to prevent and/or remediate them are proposed.

Adolescent↗
PubMed1999

Dental caries in pre-school children: associations with social class, toothbrushing habit and consumption of sugars and sugar-containing foods. Further analysis of data from the National Diet and Nutrition Survey of children aged 1.5-4.5 years.

This project examined the relative significance of dietary sugars, toothbrushing frequency and social class as predictors of caries experience (caries vs. no caries) among 1,450 British pre-school children who took part in the National Diet and Nutrition Survey. This cross-sectional survey was based on a representative sample of children aged 1.5-4.5 years studied in 1992/3. Children were classified into four groups according to social class and toothbrushing habit. Diet/caries associations were examined for biscuits and cakes, sugar confectionery, chocolate confectionery and soft drinks, and the percentage of energy from non-milk extrinsic sugars, using data on amount and frequency of consumption from 4-day weighed dietary records. In stepwise logistic regressions, the strength of the association between social class and caries experience was twice that between toothbrushing and caries, and nearly three times that between sugar confectionery and caries (other dietary variables were not significant). The association of caries with sugar confectionery (both in amount and frequency) was only present among children whose teeth were brushed less than twice a day. Toothbrushing frequency appeared to have a stronger impact on caries prevention in non-manual compared with manual children. Household expenditure on confectionery was associated with caries only among children from the manual group. The findings suggest the hypothesis that regular brushing (twice a day) with a fluoride toothpaste may have greater impact on caries in young children than restricting sugary foods.

Age Factors↗
PubMed1999

Alcohol's possible covert role: brain dysfunction, paraphilias, and sexually aggressive behaviors.

A number of studies have suggested a relationship between sexually anomalous behavior and brain dysfunction. However, in most cases, the etiology of this dysfunction remains elusive. In this paper, alcohol exposure in utero (fetal alcohol syndrome) is offered as one possible explanation for the neurophysiological abnormalities that appear to characterize a notable proportion of individuals within the paraphilic and sexually aggressive populations. It is noteworthy that the teratogenic effects of alcohol upon humans and animals often leads to a number of the behavioral and physiological abnormalities exhibited by some of these individuals.

Aggression↗
PubMed1999

Connective tissue growth factor mediates transforming growth factor beta-induced collagen synthesis: down-regulation by cAMP.

Connective tissue growth factor (CTGF) is a cysteine-rich peptide synthesized and secreted by fibroblastic cells after activation with transforming growth factor beta (TGF-beta) that acts as a downstream mediator of TGF-beta-induced fibroblast proliferation. We performed in vitro and in vivo studies to determine whether CTGF is also essential for TGF-beta-induced fibroblast collagen synthesis. In vitro studies with normal rat kidney (NRK) fibroblasts demonstrated CTGF potently induces collagen synthesis and transfection with an antisense CTGF gene blocked TGF-beta stimulated collagen synthesis. Moreover, TGF-beta-induced collagen synthesis in both NRK and human foreskin fibroblasts was effectively blocked with specific anti-CTGF antibodies and by suppressing TGF-beta-induced CTGF gene expression by elevating intracellular cAMP levels with either membrane-permeable 8-Br-cAMP or an adenylyl cyclase activator, cholera toxin (CTX). cAMP also inhibited collagen synthesis induced by CTGF itself, in contrast to its previously reported lack of effect on CTGF-induced DNA synthesis. In animal assays, CTX injected intradermally in transgenic mice suppressed TGF-beta activation of a human CTGF promoter/lacZ reporter transgene. Both 8-Br-cAMP and CTX blocked TGF-beta-induced collagen deposition in a wound chamber model of fibrosis in rats. CTX also reduced dermal granulation tissue fibroblast population increases induced by TGF-beta in neonatal mice, but not increases induced by CTGF or TGF-beta combined with CTGF. Our data indicate that CTGF mediates TGF-beta-induced fibroblast collagen synthesis and that in vivo blockade of CTGF synthesis or action reduces TGF-beta-induced granulation tissue formation by inhibiting both collagen synthesis and fibroblast accumulation.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1999

Mouse cytosolic class 3 aldehyde dehydrogenase (Aldh3a1): gene structure and regulation of constitutive and dioxin-inducible expression.

The mouse cytosolic aldehyde dehydrogenase ALDH3A1 (encoded by the Aldh3a1 gene) has previously been shown in cell culture to be markedly inducible by 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD; dioxin), downregulated by the metabolism of functional CYP1A1/1A2 enzymes, and upregulated by a gene on Chr 7 that leads to endogenous oxidative stress. In order to study the regulation of Aldh3a1 gene expression, we isolated two overlapping genomic sequences from a B6/CBA mouse genomic library that included the entire Aldh3a1 gene, along with considerable 5' and 3' flanking sequences. The Aldh3a1 gene was shown to span approximately 10 kb and comprise 11 exons including a noncoding first exon. The sequence of 3.18 kb upstream of exon 1 reveals numerous consensus transcription factor-binding sites, some of which were shown to be important in the positive and negative control of Aldh3a1 gene expression; these include seven aromatic hydrocarbon response elements (AHREs), an electrophile response element (EPRE), and AP-1, C/EBP beta, c/EBP alpha, NF-kappaB, Sp1, and NF-1 putative binding sites. Deletion fusion constructs containing regions of the Aldh3a1 gene 5' flanking sequence, ligated to chloramphenicol experiments suggested that the 5' flanking region of the gene contains a strong promoter, at least four functional AHREs appear to act cooperatively in causing dioxin-mediated upregulation, and a putative negative regulatory element (NRE) controls basal gene expression independent of dioxin inducibility. The dioxin-mediated upregulation of Aldh3a1 expression in mouse hepatoma Hepa-1c1c7 cell cultures was shown to depend exclusively on the aromatic hydrocarbon receptor. acetyltransferase (CAT) or luciferase (LUC) reporter genes, were studied. Transient transfection experiments suggested that the 5' flanking region of the gene contains a strong promoter, at least four functional AHREs appear to act cooperatively in causing dioxin-mediated upregulation, and a putative negative regulatory element (NRE) controls basal gene expression independent of dioxin inducibility. The dioxin-mediated upregulation of Aldh3a1 expression in mouse hepatoma Hepa-1c1c7 cell cultures was shown to depend exclusively on the aromatic hydrocarbon receptor.

Aldehyde Dehydrogenase↗
PubMed1999

Variation in plasma cholesterol response to dietary change.

BACKGROUND AND AIMS: Previous studies have suggested that some individuals show an appreciably larger change in total cholesterol in response to dietary change (hyper-responders) than others (minimal responders), and also that some people are more likely to respond consistently. We have examined the role of individual dietary compliance in determining total cholesterol response to changes in the nature of dietary fat. METHODS AND RESULTS: Participants completed a randomised double dietary crossover trial with a diet high in saturated fat and a diet high in polyunsaturated fat. Each period continued for four weeks without washouts. Plasma lipoproteins were measured at the end of each period. Dietary compliance was assessed by change in the reported polyunsaturated:saturated fat ratio calculated from three-day diet records, and change in polyunsaturated fat intake, determined by change in plasma triglyceride linoleate. A wide range of individual responses was observed with no evidence of two distinct populations of hyper- and minimal responders. Variation in response to the three crossovers appeared to be due mainly to variation in compliance. CONCLUSIONS: The results of this study do not support earlier suggestions of two separate populations of hyper and minimal responders to change in the nature of dietary fat, rather there is a graded range of response. In a free-living population, the extent to which individuals comply with dietary advice varies considerably and this contributes to the magnitude of cholesterol response as well as consistency on repeated dietary challenges.

Adult↗
PubMed1999

Do nursing home residents make greater demands on GPs? A prospective comparative study.

BACKGROUND: The number of people residing in nursing homes has increased. General practitioners (GPs) receive an increased capitation fee for elderly patients in recognition of their higher consultation rate. However, there is no distinction between elderly patients residing in nursing homes and those in the community. AIM: To determine whether nursing home residents receive greater general practice input than people residing in the community. METHOD: Prospective comparative study of all 345 residents of eight nursing homes in Glasgow and a 2:1 age, sex, and GP matched comparison group residing in the community. A comparison of contacts with primary care over three months in terms of frequency, nature, length, and outcome was carried out. RESULTS: Nursing home residents received more total contacts with primary care staff (P < 0.0001) and more face-to-face consultations with GPs (P < 0.0001). They were more likely to be seen as an emergency (P < 0.01) but were no more likely to be referred to hospital, and were less likely to be followed-up by their GP (P < 0.0001). Although individual consultations with nursing home residents were shorter than those with the community group (P < 0.0001), the overall time spent consulting with them was longer (P < 0.001). This equated to an additional 28 minutes of time per patient per annum. Some of this time would have been offset by less time spent travelling, since 61% of nursing home consultations were done during the same visit as other consultations, compared with only 3% of community consultations (P < 0.0001). CONCLUSION: Our study suggests that nursing home residents do require a greater input from general practice than people of the same age and sex who are residing in the community. While consideration may be given to greater financial reimbursement of GPs who provide medical care to nursing home residents, consideration should also be given to restructuring the medical cover for nursing home residents. This would result in a greater scope for proactive and preventive interventions and for consulting with several patients during one visit.

Aged↗
PubMed1999

Design, development and performance of a novel multidose dry-powder inhaler.

The authors describe the design and development of a breath-actuated multidose dry-powder inhaler and summarize the in vitro and in vivo data demonstrating its robustness and performance in the laboratory and during clinical use. Drugs for the treatment of asthma--including budesonide, beclomethasone dipropionate and salbutamol--when formulated with lactose powder as a carrier and dispensed via this device, have exhibited clinical efficacy and safety profiles comparable with standard pressurized metered-dose inhalers and dry-powder formulations.

Anti-Asthmatic Agents↗