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Biomedical subjects

J A Bell

Publications and source records attributed to J A Bell.

197 records · Page 11Linked to original sources
PubMedDate not supplied

Utilization of prenatal cytogenetic diagnosis in women of advanced maternal age in Australia, 1979-1982.

This paper reports the results of a complete national survey to measure utilization rates of prenatal cytogenetic diagnosis (P.C.D.) in women of advanced maternal age in Australia. P.C.D. has been available throughout Australia for the last decade. Every laboratory in Australia providing a P.C.D. service for the years 1979-1982 took part in this study. Utilization rates (both National and State rates) by ages of mothers, are presented. Big interstate differences exist. The 1982 National P.C.D. utilization rate for pregnant women who were 40 years of age and over was 38.8 per cent, and this rate has shown an average annual increase of 9 per cent. In those four States which offered P.C.D. to pregnant women of 35 years or over the median utilization rate was 20 per cent. These Australian rates indicate an under-utilization of P.C.D. services with (in 1982) 50-80 per cent of 'at risk' women not being tested. Factors which influence this are discussed.

Adult↗
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Functional corticotropin-releasing factor receptors in neonatal rat spinal cord.

The present study localized corticotropin-releasing factor (CRF) receptors and studied the action of CRF in the neonatal rat spinal cord preparation. Lumbar CRF receptors were present in highest concentrations in laminae I and II with progressively lower concentrations in lamina IX and intermediate and central zones respectively. CRF directly and indirectly depolarized lumbar motoneurons in a concentration-related manner and the putative receptor antagonist, alpha helical oCRF(9-41), partially blocked the depolarizing response to CRF. The electrophysiological responses to CRF and the distribution of receptors within the spinal cord suggest that CRF may play a physiological role in regulating spinal cord reflex function.

Animals↗
PubMedDate not supplied

Use of site-directed mutagenesis to obtain isomorphous heavy-atom derivatives for protein crystallography: cysteine-containing mutants of phage T4 lysozyme.

Five different cysteine-containing mutants of the lysozyme from bacteriophage T4 were used to explore the feasibility of using site-directed mutagenesis to generate isomorphous heavy-atom derivatives for protein crystallography. Cysteines 54 and 97, present in wild-type lysozyme, can be readily reacted with mercuric ion to produce an excellent isomorphous heavy-atom derivative. Mutants with an additional cysteine at position 86, 146, 153 or 157, or with Cys 97 replaced by Val, were engineered by site-directed mutagenesis. The mutant lysozyme Thr 157----Cys reacts with mercuric chloride to give an excellent new derivative although Cys 157 is only approximately 60% substituted with the heavy atom. The cysteine at position 146 is largely buried but reacts readily with mercuric chloride. In this case the isomorphism is poor and the resultant derivative is of marginal quality. Cys 153 reacts rapidly with mercuric ion but the derivative crystals do not diffract. The mutant Pro 86----Cys does not yield a particularly good heavy-atom derivative. This is due in part to a loss of isomorphism associated with the mutation. In addition, Cys 86 shows very little reactivity towards mercurials even though it is fully exposed to solvent. The mutation Cys 97----Val was used to explore the possibility of creating an independent derivative by deleting a heavy-atom site already present in wild-type lysozyme. In all cases that were tested, the quality of the heavy-atom derivative was improved by using as an isomorphous pair mercury-substituted mutant versus non-substituted mutant rather than mercury-substituted mutant versus (non-substituted) wild-type lysozyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
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Ascorbic acid protects neurons from injury induced by glutamate and NMDA.

We have previously shown that redox phenomena regulate the function of the NMDA receptor in the brain and that ascorbic acid (AA) behaves as a receptor antagonist. Here we examined the potential neuroprotective effects of AA against toxicity induced by NMDA and glutamate in rat cerebral cortical neurones in cultures. AA completely protected against injury induced by 100 microM NMDA and markedly reduced cell death induced by 500 microM NMDA or 50 microM glutamate. Dehydroascorbic acid (DHAA) did not provide significant neuroprotection. Hence, we propose that AA may serve in the CNS as a neuroprotectant.

Animals↗
PubMedDate not supplied

Validation of two anxiety scales in a university primary care clinic.

Psychometric scales for the assessment of anxiety disorders have not been validated in primary care settings. We undertook a study to validate two brief, self-administered anxiety scales, Sheehan's Patient-Rated Anxiety Scale and Beck's Cognition Checklist, in a university primary care clinic. The two scales were compared with a diagnostic standard, the Structured Clinical Interview for the revised third edition of the Diagnostic and Statistical Manual (SCID). Of 87 randomly selected patients, 25 had an anxiety disorder by the SCID. Anxious patients scored statistically higher on both scales than nonanxious persons on both the Beck and Sheehan scales. Based on receiver operating characteristics curve analysis, we found that these two scales correctly classified 72% to 77% of anxious patients. Of the two scales, the Sheehan scale performed better, with a specificity of 94% and positive predictive value of 75%. Our results suggest that these instruments may be useful in the assessment of the anxiety disorders in medical populations.

Academic Medical Centers↗
PubMedDate not supplied

One peer review organization's experience in developing hospital peer groups.

The Health Care Quality Improvement Initiative is moving Medicare's quality improvement activities from review and action on individual cases to the analysis of patterns of care. A primary source for pattern analysis is the mortality data presented in the Medicare Hospital Information release. One of the requirements set forth by the Health Care Financing Administration is that peer review organizations classify hospitals into peer groups in order to compare mortality rates within and among groups. It is hoped that this type of analysis will lead to a better understanding of the relationship between process and outcome for a variety of medical conditions. This report describes the experience of one peer review organization in establishing hospital peer groups.

Centers for Medicare and Medicaid Services, U.S.↗
PubMedDate not supplied

A cross-validation study for predictors of scores on state board examinations.

Regression equations were computed and cross-validated for predicting nurses' scores on each of the five state board examinations (SBEs). Scores on five National League for Nursing (NLN) achievement tests of 101 nurses who graduated from a baccalaureate program between 1968 and 1972 were used as predictor variables. Stepwise regression analysis was used to compute the equations which were, in turn, used to predict the SBE scores for an independent sample of nurses who graduated in 1973. Cross-validation correlations between the predicted and actual obtained scores of the 1973 graduates ranged from .64 to .81. For each equation, the NLN test scores in Nursing of Children and Obstetric Nursing were consistently the best indicators of performance on the SBEs. Additionally, a factor analysis indicated that the SBEs do not measure independent entities, but that all five examinations have high loadings on the same factor. The results suggest that nursing programs should develop and validate prediction equations to assist nurses in preparing for SBEs.

Achievement↗
PubMedDate not supplied

The significance of p53 autoantibodies in the serum of patients with breast cancer.

Serum p53 autoantibodies were studied in 82 patients with Stage 1 or 2 breast cancer using an ELISA assay. Tissue expression of p53 in these patients was also examined. High levels of serum p53 autoantibodies were detected in 48% (39/82) patients, while 23% (19/82) were tissue positive. Patients with high serum p53 autoantibodies levels were not significantly different to those with low levels with respect to, tissue p53, tumour grade, size, stage or oestrogen receptor status. Tissue immunoreactivity for p53 was significantly associated with tumour grade and negative oestrogen receptor status. Patients in both groups were followed for a median of over five years but the presence of p53 autoantibodies in serum was not prognostic with respect to disease free interval or survival. In this study detection of p53 autoantibodies in serum does not correlate with any of the usual tumour related prognostic factors, nor does it correlate with clinical outcome.

Antibodies, Neoplasm↗
PubMedDate not supplied

Male breast cancer: pathological and immunohistochemical features.

BACKGROUND: male breast cancer is uncommon and studies regarding the potential clinical relevance of the histopathological and immunohistochemical features are infrequently reported. MATERIALS AND METHODS: We investigated the biological characteristics of forty-one male patients with invasive breast cancer by assessing histopathological and multiple immunohistochemical features. RESULTS: The majority were no special type (ductal) (37/41), lobular cancer was not seen. 73% were histological grade 3, 93% were positive for oestrogen receptor and 73% for progesterone receptor. The proportion of cancers positive for c-ebB-2 (45%), EGFR (20%), p53 (58%), MiB1 (40%), NCRC11 (78%), were similar to reports for female breast cancer. Nonsignificant associations between poor survival outcome and grade 3 tumours, and positive tissue staining for MiB1 and p53 were seen. CONCLUSION: While there ar similarities in the biological features of breast cancer in males and females, some differences were identified. Male breast cancer is more likely to be grade 3 tumours and hormone receptor positive.

Biomarkers, Tumor↗