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Biomedical subjects

M Nelson

Publications and source records attributed to M Nelson.

At least 217 records · Page 12Linked to original sources
PubMed1997

Effect of calcium intake and physical activity level on bone mass and turnover in healthy, white, postmenopausal women.

Calcium intake and physical activity level (PAL) were assessed by questionnaire in 124 healthy women aged 52-62 y to determine the effect of calcium intake and PAL on bone mass and turnover. Four groups were identified according to their different reported calcium intakes and PALs. Bone mineral density (BMD) at the spine, hip, and left os calcis was measured together with total bone mineral content (TBMC) with dual-energy X-ray absorptiometry. Bone formation and resorption biochemical markers were measured in fasting samples of blood and urine. Women with the highest calcium intakes and PALs had the highest BMD at all sites compared with those with the lowest calcium intakes and PALs (P < 0.001). Calcium intake and PAL were positively correlated with BMD at all sites. Bone turnover markers did not explain the variation in bone mass between groups. In stepwise-multiple-regression analysis only calcium intake, physical activity, age, or weight remained as independent predictors of BMD and TBMC. When subjects were divided by past PALs, calcium intake and PAL were second to age and weight in their influence on spinal and hip BMD, but remained influential on the os calcis and whole body. We conclude that current high calcium intakes and PALs influence BMD at the os calcis and TBMC and protect bone mass in women 5-12 y postmenopausal at all measured sites, including the spine and hip. This finding does not exclude the possibility of past influences of calcium and activity on bone mass.

Biomarkers↗
PubMed1997

Feasibility of conducting cardiovascular outcome research in Australian general practice: results from the ANBP2 pilot study. Australian National Blood Pressure Study.

1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was > or = 160 mmHg systolic or > or = 90 mmHg diastolic if systolic BP was > or = 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82,000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP > or = 160/90 mmHg. Forty-seven per cent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.

Aged↗
PubMed1997

Antenatal screening for HPA-1a by flow cytometry.

Pregnant women who attended antenatal clinics at King George V Hospital, the Birth Centre or were referred by obstetricians from February 19 July, 1996 were screened for the platelet antigen HPA-1a by flow cytometry. Forty out of 2,300 (1.7%) were found to be negative for this antigen. Of the 28 women followed throughout their pregnancy, none developed antibody to HPA-1a. Platelet counts performed on samples from 17 babies born to 17 of these mothers were all normal. This study proves the simplicity and rapidity of flow cytometry for platelet antigen screening. The results were comparable with the Solid Phase Red Cell Adherence (SPRCA) method and with PCR. The lack of a plentiful supply of specific antibody and the rarity of fetomaternal alloimmune thrombocytopenia (FMAIT) argue against the introduction of routine screening for maternal HPA-1a status at the present time.

Adolescent↗
PubMed1997

Validation in London of a physical activity questionnaire for use in a study of postmenopausal osteopaenia.

STUDY OBJECTIVE: To determine the validity of a self administered physical activity questionnaire to be used as part of a screening device for postmenopausal osteopaenia (with additional questions on medical history and calcium intake). DESIGN: A questionnaire was posted to 86 perimenopausal women to enquire about weekly hours spent in non-sedentary activity at work, in the household, and during leisure hours. Subjects who returned the questionnaire were visited at home and asked to complete a four day activity diary and subsequently to undertake a submaximal estimate of VO2 MAX, carried out using a treadmill ergometer. They were interviewed to clarify questionnaire and diary entries. Questionnaire validity was assessed in comparison with the diary estimates of hours of activity and with VO2 MAX. PARTICIPANTS: A total of 86 perimenopausal women aged 43-54 years were randomly selected from a GP list in Hammersmith, London. Thirty five women (41%) returned the questionnaire. They were visited at home, given the diary to complete, and invited to attend the physiology laboratory for VO2 MAX measurements. Twenty six of the 35 (74%) completed the study and were included in the final analysis. MAIN RESULTS: Women spent an average of 51 hours per week in non-sedentary activities. Questionnaire and diary yielded similar results (51.05 versus 51.30 h/wk), and there was a good correlation between diary and questionnaire estimates of total weekly hours of non-sedentary activity (r = 0.45, p < 0.05). Other significant correlations were for standing (r = 0.69, p < 0.01), leisure activities (r = 0.66, p < 0.01), and for light household activities (r = 0.42, p < 0.05). Correlations were better for employed than non-employed subjects. In relation to the diary, the questionnaire correctly classified 60% into the top or bottom half of the distribution activity. Sensitivity and specificity of the questionnaire were both equal to 61.5%. CONCLUSIONS: The questionnaire is useful for classifying subjects according to their level of activity, especially when administered in conjunction with an interview. The four day diary provided a useful reference measure and a focus for discussing activity patterns during an interview related to the questionnaire responses.

Activities of Daily Living↗
PubMed1997

Building the dream team: don't make it a nightmare.

This article covers the often overlooked area of team management concepts through a discussion of what many companies have done to implement these new concepts successfully. It describes the basics of how to and also explains why people resist the process of implementation. The main topics are (1) team formation, (2) pitfalls to avoid, and (3) team measurement.

Conflict, Psychological↗
PubMed1997

Nutrient recycling systems of Biosphere 2. Litterfall, decomposition, and wastewater recycling: results from the 1991-1993 closure experiment.

Important aspects of nutrient recycling in Biosphere 2 were plant litterfall/leaf decomposition in the terrestrial biomes and sewage and wastewater processing by a constructed wetland system. During the second year of closure, annual litterfall ranged from 1317 +/- 283 g/m2 in the lowland rainforest to 141 +/- 58 g/m2 in the desert sand dune area. Litterfall patterns followed different seasonal regimes in the biomes. Leaf decomposition averaged 90%/year in Biosphere 2, with the smallest leaf loss in the desert biome. For maintenance of soil fertility in the agricultural area, inedible crop material and domestic animal manure was composted, and human waste products and wastewater from people, labs, and domestic animals was processed in a 41-m2 constructed wetland. The wetland produced 1200 kg of fodder and remaining nutrients were returned to the soils via irrigation water.

Biomass↗
PubMed1997

The benefits of continuous performance measurement.

Performance measurement is fast becoming a way of life for health care providers in this age of increased accountability and outcomes reporting. Health care organizations are well advised to carefully select measures and measurement tools to adequately meet the demands of others in a cost-effective and beneficial manner. A strategic plan and implementation of an effective performance measurement system will help to guide an organization to evaluate key processes and implement changes to improve patient care. In February 1997, the Joint Commission announced new accreditation requirements for hospital and long-term care organizations; these organizations must enroll in an acceptable performance measurement system by the end of 1997 and prepare to submit data to the Joint Commission for at least two clinical measures within the first quarter of 1999.

Cost-Benefit Analysis↗
PubMed1997

Clinical audit--linking continuing medical education (CME) and practice assessment (PA).

The Quality Assurance (QA) Program of the Royal Australian College Of General Practitioners has required doctors to engage in practice assessment (PA) activities. Clinical audit is one of these activities and has been used as an assessment tool in the Graduate Diploma in Family Medicine at Monash University, in impact evaluation of educational programs as well as a means of pooling morbidity data for research purposes and peer review. Examples of these uses of clinical audit are cited, with discussion in greater detail in relation to a dermatology course, cardiovascular risk factor detection and ongoing management of congestive cardiac failure. Doctors participating in these audit activities have almost invariably described them as a valuable reflective educational exercise with changes in clinical practice occurring after the audit in a number of instances.

Australia↗
PubMed1997

Expression of p53 protein in actinic keratosis, adjacent, normal-appearing, and non-sun-exposed human skin.

Nonmelanoma skin cancer, including both squamous cell carcinoma and basal cell carcinoma, is a significant and increasing health problem in the United States. The precursor lesion of cutaneous squamous cell carcinoma, actinic keratosis (AK), is a major risk factor for nonmelanoma skin cancer, and it is also a marker of long-term sun exposure. AKs themselves can serve as biomarkers in chemopreventive studies, but in addition, they may contain phenotypic and genetic alterations that are related to the process of UV-induced skin carcinogenesis. One of these alterations, the tumor suppressor gene p53, is altered early in UV-induced skin carcinogenesis in humans. p53 protein expression was measured by immunohistochemistry in biopsies from AKs, tissue immediately adjacent to AKs (AK-adjacent), normal-appearing upper medial arm skin, and non-sun-exposed skin from 19 subjects. There was a significant difference and a progressively increasing mean p53 labeling index in total epidermis (basal and suprabasal layers) between upper medial arm skin (0.9 +/- 1.8%) and AK-adjacent (12.1 +/- 14.4%; P = 0.0004) and between AK (27.7 +/- 21.3%) and AK-adjacent skin (P = 0.04), whereas upper medial arm skin was marginally different from non-sun-exposed skin (0.1 +/- 0.2; P = 0.05). This pattern of p53 expression was also seen when epidermis was separated into basal and suprabasal layers. We conclude that epidermal p53 protein expression is associated with histological evidence of chronic sun damage.

Aged↗
PubMed1997

New computer-based tools for empiric antibiotic decision support.

Since 1995 we have been developing a decision-support model, called Q-ID, which uses a series of infectious disease knowledge bases to make recommendations for empirical treatment or to check the appropriateness of current antibiotic therapy. From disease manifestations and risk factors, a differential diagnosis for the patient is generated by a diagnostic medical expert system. The resulting probability of each: disease is multiplied by the expected benefit in improved mortality and morbidity from optimal antibiotic treatment of each disease. To generate empirical treatment recommendations, site-specific data on sensitivity to antibiotics of each organism is used as an estimate of the likelihood of achieving maximum benefit for each disease on the patient's differential. Combining this data with drug and patient specific factors, the model recommends the antibiotic(s) most likely to produce the optimal benefit in this patient with the least risk and expense. In this paper the model is described, excerpts from each of the knowledge bases are presented, and performance of the model in a real case is shown for illustration.

Aged↗
PubMed1997

Der(16)t(1;16)(q21;q13) as a secondary structural aberration in yet a third sarcoma, extraskeletal myxoid chondrosarcoma.

Cytogenetic analysis of an extraskeletal myxoid chondrosarcoma revealed a der(16)t(1;16)(q21;q13) in addition to the t(9;22)(q22;12) described as characteristic for this chondrosarcoma clinicohistopathologic subtype. An identical der(16) has been identified as the most common secondary structural aberration in Ewing's sarcoma and alveolar rhabdomyosarcoma.

Chondrosarcoma↗
PubMed1997

Laboratory diagnosis of plague.

In response to an outbreak of a plague-like disease in India, the Public Health Laboratory Service (PHLS) in the UK distributed advice on the isolation and identification of Yersinia pestis. Some of the procedures outlined were evaluated using a number of isolates of Y. pestis, complemented with in-house techniques detecting virulence genes or their products. These laboratory investigations are limited in that they are either only indicative or they take too long (48 hours or more), and thus represent a serious delay to the patient. Successful patient management must be based on a case history, and therapy should be started immediately. Laboratory diagnosis will subsequently rule out most pathogens which cause similar infections, yet will still require confirmation by a reference laboratory.

Bacteriological Techniques↗
PubMed1996

Activation of multiple mitogen-activated protein kinase signal transduction pathways by the endothelin B receptor requires the cytoplasmic tail.

Endothelin is a 21-amino acid peptide with remarkably diverse biological properties, including potent vasoconstriction, induction of mitogenesis, and a role in the development of blood vessels. In the present study, stimulation of the endothelin B receptor was found to activate three distinct mitogen-activated protein kinase signal transduction pathways, the extracellular regulated kinase (ERK) 2, c-Jun N-terminal kinase 1 (JNK), and p38 kinase. These mitogen-activated protein kinase isozymes are thought to mediate very different biological outcomes, suggesting that the observed pattern of kinases activation may be important for the diverse biological properties of endothelin. The cytoplasmic tail of the endothelin B receptor was found to be required for activation of all three mitogen-activated protein kinases and stimulation of intracellular calcium levels. An endothelin B receptor truncated at the C-terminal tail was not able to stimulate the mitogen-activated protein kinases or increase cytosolic free calcium. Furthermore, ectopic expression of the cytoplasmic tail attenuated signaling through the wild type receptor. The observed ERK activation appeared to be mediated by heterotrimeric G proteins, since ectopic expression of a transducin alpha-subunit inhibited endothelin-stimulated ERK activation. The data suggest that the cytosolic tail of the endothelin B receptor is involved in calcium mobilization and mitogen-activated protein kinase activation via a G protein-dependent mechanism.

Animals↗