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Biomedical subjects

R McMahon

Publications and source records attributed to R McMahon.

At least 19 recordsLinked to original sources
PubMed1992

Short-term intraindividual variability in hemostasis factors. The ARIC Study. Atherosclerosis Risk in Communities Intraindividual Variability Study.

Recent epidemiologic studies found that there is a strong association of hemostatic factors with ischemic heart disease. The Atherosclerosis Risk in Communities (ARIC) Intraindividual Variability (IIV) Study was conducted to estimate the various components of variation in hemostasis factors measured in the ARIC Study and to estimate the measures of repeatability of these factors. A total of 39 subjects (16 men, 23 women) were studied. Each had blood collected three times, with a 1- to 2-week interval between each visit. The contributions of between-person variability, within-person (biologic) variability, and processing and assay variability were estimated. Then the reliability coefficient R was estimated as the proportion of total variance accounted for by between-person variance. The reliability coefficient can be interpreted as the correlation between measures made at repeat visits. Among the various analytes, the reliability coefficients were quite high for activated partial thromboplastin time and plasma factor VIII (R = 0.92, 0.86, respectively). Low repeatability was obtained for antithrombin III activity and protein C (R = 0.42, 0.56, respectively). The lack of repeatability for these variables derives mostly from the processing (field center and laboratory) variation. Other analytes--fibrinogen, plasma factor VII, and von Willebrand factor--were intermediate in repeatability. In comparing the analyte-specific high-level to low-level groups, no substantial difference of within-person plus method coefficient of variation between the two groups was found for any analyte except for factor VIII, whereas the corresponding variance components for most analytes were higher for the higher analyte level. Reliability coefficients from this ARIC IIV study are generally higher than those found in other studies, and this is related to the relative variations in populations studied and to the time between measurements.

Antithrombin III↗
PubMed1992

Skin problems beneath the breasts of in-patients: the knowledge, opinions and practice of nurses.

A survey of knowledge and nursing practice in relation to sub-mammary skin problems was conducted among ward sisters and primary nurses in one district health authority. Respondents identified a number of characteristics as predisposing factors, with obesity and poor hygiene being mentioned most frequently. A very wide selection of nursing interventions was recommended, with nurses who mentioned pharmacologically active topical preparations reporting a significantly greater number of recurrences among patients than those who relied on less sophisticated regimes. Nurses expressed a variety of opinions about the effect that this condition has on patients, ranging from no effect at all to pain and discomfort. These findings highlight the lack of a coherent strategy for treating this problem and support the continuation of a research programme examining sub-mammary skin problems and the nursing response to them.

Attitude of Health Personnel↗
PubMed1992

Long-term effect of retrobulbar hematomas on the vision of cynomolgus monkeys.

Using the monkey model previously developed, we investigated the long-term effects of retrobulbar hematoma-induced retinal ischemia on functional vision and retinal histology. In this experimental model, ischemic periods of up to 120 minutes did not cause permanent visual deficits, as measured by flashed evoked visual potentials. Similarly, retinal histology showed no evidence of ischemic injury. From this we conclude that blindness after blepharoplasty is not due to retrobulbar hematomas alone and that additional predisposing factors are involved. The most likely additional factor is preexisting occult vascular ocular pathology.

Animals↗
PubMed1990

Power and collegial relations among nurses on wards adopting primary nursing and hierarchical ward management structures.

Power and collegial relations among nurses on a number of hospital wards were analysed using a mixed methodology. Half the wards had adopted primary nursing whilst the rest continued with hierarchical management structures. Nurses' interactions were recorded as they worked, as were those that occurred during the shift handover period. The nurses' own perceptions of their collegial relations were measured using a 'Likert scale' type of questionnaire. Qualitative analysis of the observational data suggested that genuine differences in the nature of the power relations existed between the laterally and hierarchically managed wards. Some of the nurses on the primary nursing wards were observed to identify and discuss solutions to their patients' nursing problems, whereas these were either not followed-up or referred to other health care workers on the traditionally managed wards. Statistical analysis of the questionnaires suggested that nurses on the primary nursing wards found their collegial communication to be significantly more collaborative than that of the nurses on the hierarchical wards. Comparison between specialties did not reveal a statistical difference.

Attitude of Health Personnel↗
PubMed1988

Enzymatic analysis of total- and HDL-cholesterol: comparison with the standardized Liebermann-Burchard method used by the Lipid Research Clinics program.

We compared two enzymatic cholesterol methods with the standardized chemical method used in the Lipid Research Clinic's (LRC) program. The methods were used to measure total cholesterol and high density lipoprotein (HDL) cholesterol in heparin-MnCl2 supernatants of 1,812 sera collected over a 16-mth period from subjects who were sampled as part of the Hispanic Health and Nutrition Examination Survey. Thirty percent of the subjects had fasted for 12 h or more before venepuncture. The enzymatic total cholesterol values were 1.4-1.8% lower than the LRC method and both enzymatic methods correlated highly with the LRC method (r greater than 0.97). The enzymatic HDL cholesterol values were 2.4 and 6.4% higher than the LRC method, and the correlation between the enzymatic and LRC methods was greater than 0.93. The differences between the enzymatic and LRC methods were the same in samples from fasting and non-fasting subjects.

Cholesterol↗
PubMed1988

The '24-hour reality orientation' type of approach to the confused elderly: a minimum standard for care.

The use of the two principle types of reality orientation with the confused elderly has been the subject of research by nurses, psychiatrists and psychologists. Reviews of this research suggest that the effects of these therapies on patient outcomes are extremely limited. However, a number of writers advocate their use on the grounds that their implementation results in more individualized care by nurses. This argument is rejected in favour of the demonstrated effect of introducing individualized care from a basis in nursing theory. Nursing theory also provides the remit for nurses to control the physical and interpersonal environment of the confused elderly patient. By examining moral principles as they are applied to nursing, it is argued that the nature of that environmental control should be towards a 24-hour reality orientation type approach. This should be implemented in an individualized way and should form the basis of a minimum standard of care for this client group.

Aged↗
PubMed1986

Predictive parameters of successful varicocele repair.

A total of 130 men presenting with oligospermia and clinically identifiable scrotal varicoceles was evaluated, treated surgically and followed for 1 year for pregnancy rate. The treatment outcome was compared to an age-matched cohort of 83 oligospermic men who had received empirical medical therapy with clomiphene citrate (25 mg. per day) for the same 1-year interval. This study was done to contrast treatment modalities in infertility and not as a strict control. Only eugonadotropic patients in both groups were used for comparison. In the varicocele group the over-all pregnancy rate was 38.5 per cent. Four variables (a lack of testicular atrophy, sperm density greater than 50 million per ejaculate, sperm motility 60 per cent or more and serum follicle-stimulating hormone values less than 300 ng. per ml.) proved to be accurate preoperative predictors of postoperative pregnancy success. Four other variables (varicocele size and laterality, sperm forward progression greater than 2 and normal sperm morphology 60 per cent or more) did not yield statistically significant rates of improvement in pregnancy postoperatively. The pregnancy rate of the eugonadotropic patients undergoing varicocele repair was 45.8 per cent. Despite statistical similarity in patient age, sperm density and mean gonadotropin levels the medically treated patients had a pregnancy rate of only 25.5 per cent, significantly lower than the surgically treated patients. In summary, patients with an identifiable varicocele had a greater chance of achieving a pregnancy following surgical correction than did those treated with empirical drug therapy. In addition, certain preoperative variables in the physical and laboratory analyses appeared to portend a greater surgical response.

Adult↗