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Biomedical subjects

M Walker

Publications and source records attributed to M Walker.

At least 289 records · Page 16Linked to original sources
PubMed1996

Career streaming: a model of career development.

1. A career is an individually perceived sequence of attitudes and behaviors associated with work related experiences and activities over the span of the person's life. 2. Every career ultimately reaches some sort of a plateau--a position from which someone is unlikely to advance to a higher level of responsibility in their career. The danger is they will become unmotivated and apathetic. 3. One method proposed for keeping employees challenged and interested is career streaming--a model of career development for employees within a defined professional field. The challenge is to provide a range of levels with defined skills for each level. The model developed for an occupational health service is provided as an example.

Career Mobility↗
PubMed1996

Acute rejection of marrow grafts in patients transplanted from a partially mismatched related donor: clinical and immunologic characteristics.

Bone marrow transplantation (BMT) from a partially mismatched related donor (PMRD) provides a treatment option for patients lacking a matched sibling donor. T lymphocyte depletion of the graft reduces the risk of severe graft-versus-host disease, but may increase the risk of graft failure. We evaluated the pattern of acute graft rejection in eight patients receiving PMRD BMT with respect to the conditioning therapy, diagnosis, age and sex of donor and recipient, degree of HLA mismatch, and peripheral blood immunophenotype at the time of graft failure. All grafts were partially depleted of T lymphocytes. Marrow grafts infused into patients who experienced acute rejection did not differ significantly in nucleated cell dose, degree of T lymphocyte depletion, T cell dose, or CFU-GM/kg infused, from those received by 31 patients who showed durable engraftment. In three of four patients who rejected their grafts, and had sufficient peripheral blood cells for immunophenotyping, a CD3+CD8+ T lymphocyte phenotype was predominant at the time of acute rejection. In one patient rejection was associated with a predominant population of CD3+CD4+ T lymphocytes. Rejection was significantly associated with chronic myelogeneous leukemia and in patients mismatched by more than two antigens.

Adult↗
PubMed1996

DNA ploidy on cytologic and tissue sections of breast lumps. A comparison using image analysis.

OBJECTIVE: Ploidy correlation between cytologic and histologic breast specimens would permit preoperative measurement of ploidy and may assist in patient management. STUDY DESIGN: DNA indices were measured on fine needle aspirates (FNAs) of 50 breast lumps and the results compared with ploidy of histologic specimens from the same lump. RESULTS: Thirty-six of 50 were histologically malignant, and 14/50 were benign. The mean DNA index of malignant tissue sections was 1.23 (range, 0.61-2.62) and on corresponding cytology was 1.49 (range, 0.79-3.18). Fourteen benign tissue sections had a mean DNA index of 0.94 (range, 0.51-1.37) and a mean DNA index of 1.06 (range, 0.74-2.13) on cytology. DNA indices of FNAs and corresponding tissue sections revealed a correlation between the two (Pearson's correlation coefficient = .386, P value = .006). CONCLUSION: Our results show that the DNA indices are comparable using image analysis on FNAs and tissue sections on the same surgical breast specimens. This demonstrates that ploidy can be achieved on cytologic breast material and may have a role in the preoperative assessment of breast cancers.

Breast Neoplasms↗
PubMed1995

Marital status, change in marital status, and mortality in middle-aged British men.

The effects of marital status and change in marital status on mortality among middle-aged British men were examined in a prospective cohort study, the British Regional Heart Study. This is a nationally representative cohort of men selected at random from general medical practices in 24 towns in England, Wales, and Scotland. It comprises 7,735 men aged 40-59 recruited in 1978-1980 and followed up for 11.5 years. Marital status and a wide range of biologic and lifestyle variables were measured at screening, and changes in marital status were assessed after 5 years. Single (never-married) men had an increased risk of cardiovascular disease mortality (relative risk (RR) = 1.5, 95% confidence interval (CI) 1.0-2.2) and noncancer, noncardiovascular mortality (RR = 1.8, 95% CI 1.1-3.3) after adjustment for potentially confounding variables: age, social class, smoking, recall of ischemic heart disease, recall of diabetes mellitus, use of antihypertensive drugs, body mass index, physical activity, alcohol intake, employment status, systolic blood pressure, blood cholesterol, and forced expiratory volume in 1 second. Divorced/separated men were not at increased risk of mortality, and widowed men were only at increased risk of other non-cardiovascular disease mortality (RR = 2.4, 95% CI 1.1-5.3). There was no effect of marital status on cancer mortality. Men who divorced during the follow-up period were at increased risk of both cardiovascular disease mortality (RR = 1.9, 95% CI 0.9-3.9) and other non-cardiovascular disease mortality (RR = 4.0, 95% CI 1.5-10.6), but men who became widowed during this time were not at increased risk. The excess mortality among single and recently divorced men was not explained by poor health or by exposure to a wide range of risk factors. It is unlikely that selection bias, chance, or artifact is responsible for the general relation between marital status and mortality. Variable and incomplete control for confounding by socioeconomic status and risk factors for common diseases may explain some of the inconsistencies observed between studies and between different categories of unmarried men (i.e., never-married, widowed, and divorced). It is possible that the social support offered by marriage exerts a protective effect for some men.

Adult↗
PubMed1995

Birth weight and blood pressure: cross sectional and longitudinal relations in childhood.

OBJECTIVE: To examine cross sectional and longitudinal relations between birth weight and blood pressure in childhood. DESIGN: Cross sectional study of primary school children aged 9-11 years, with analysis in relation to previous measurements at 5-7 years in a subgroup. SETTING: 20 primary schools in Guildford and Carlisle. SUBJECTS: 1511 children measured at 9-11 years (response rate 79%), including 549 who had been measured at 5-7 years. MAIN OUTCOME MEASURES: Blood pressure at 9-11 years, change in blood pressure between 5-7 and 9-11 years, birth weight (based on maternal recall), and placental weight (based on birth records). RESULTS: At 9-11 years birth weight was inversely related both to systolic blood pressure (regression coefficient -2.80 mm Hg/kg; 95% confidence interval -3.84 to -1.76) and to diastolic blood pressure (regression coefficient -1.42 mm Hg/kg; -2.14 to -0.70) once current height and body mass index were taken into account. Placental weight was inversely related to blood pressure after adjustment for current height and body mass index but placental ratio (placental weight to birth weight) was unrelated to blood pressure. Between 5-7 and 9-11 years systolic blood pressure rose more rapidly in children of lower birth weight (regression coefficient -1.71 mm Hg/kg; -3.35 to -0.07). This effect seemed to be stronger in girls. CONCLUSIONS: Birth weight rather than placental ratio is the early life factor most importantly related to blood pressure in childhood. The results support the possibility of "amplification" of the relation between birth weight and blood pressure, particularly in girls.

Aging↗
PubMed1995

Low serum total cholesterol concentrations and mortality in middle aged British men.

OBJECTIVE: To examine the relation between low serum total cholesterol concentrations and causes of mortality. DESIGN: Cohort study of men followed up for an average of 14.8 years (range 13.5-16.0 years). SETTING: One general practice in each of 24 British towns. SUBJECTS: 7735 men aged 40-59 at screening selected at random from the 24 general practices. MAIN OUTCOME MEASURES: Deaths from all causes, cardiovascular causes, cancer, and non-cardiovascular, non-cancer causes. RESULTS: During the mean follow up period of 14.8 years there were 1257 deaths from all causes, 640 cardiovascular deaths, 433 cancer deaths, and 184 deaths from other causes. Low serum cholesterol concentrations (< 4.8 mmol/l), present in 5% (n = 410) of the men, were associated with the highest mortality from all causes, largely due to a significant increase in cancer deaths (age adjusted relative risk 1.6 (95% confidence interval 1.1 to 2.3); < 4.8 v 4.8-5.9 mmol/l) and in other non-cardiovascular deaths (age adjusted relative risk 1.9 (1.1 to 3.1)). Low serum cholesterol concentration was associated with an increased prevalence of several diseases and indicators of ill health and with lifestyle characteristics such as smoking and heavy drinking. After adjustment for these factors in the multivariate analysis the increased risk for cancer was attenuated (relative risk 1.4 (0.9 to 2.0) and the inverse association with other non-cardiovascular, non-cancer causes was no longer significant (relative risk 1.5 (0.9 to 2.6); < 4.8 v 4.8-5.9 mmol/l). The excess risks of cancer and of other non-cardiovascular deaths were most pronounced in the first five years and became attenuated and non-significant with longer follow up. By contrast, the positive association between serum total cholesterol concentration and cardiovascular mortality was seen even after more than 10 years of follow up. CONCLUSION: The association between comparatively low serum total cholesterol concentrations and excess mortality seemed to be due to preclinical cancer and other non-cardiovascular diseases. This suggests that public health programmes encouraging lower average concentrations of serum total cholesterol are unlikely to be associated with increased cancer or other non-cardiovascular mortality.

Adult↗
PubMed1995

Smoking cessation and the risk of stroke in middle-aged men.

OBJECTIVE: To examine the effects of giving up smoking, years since quitting smoking and the quantity of cigarettes smoked, and primary pipe or cigar smoking on the risk of stroke. DESIGN, SUBJECTS, AND SETTING: A prospective study of cardiovascular disease and its risk factors in 7735 men aged 40 through 59 years drawn at random from the age-sex registers of one general practice in each of 24 British towns from 1978 through 1980 (the British Regional Heart Study). MAIN OUTCOME MEASURE: Incidence of fatal and nonfatal major stroke events (strokes) during an average follow-up period of 12.75 years. RESULTS: During the 12.75 years of follow-up, there were 167 major stroke events (43 fatal and 124 nonfatal) in the 7264 men with no recall of previous ischemic heart disease or stroke. After full adjustment for other risk factors, current smokers had a nearly fourfold relative risk (RR) of stroke compared with never smokers (RR, 3.7; 95% confidence interval [CI], 2.0 to 6.9). Ex-cigarette smokers showed lower risk than current smokers but showed excess risk compared with never smokers (RR, 1.7; 95% CI, 0.9 to 3.3; P = .11); those who switched to pipe or cigar smoking showed a significantly increased risk (RR, 3.3; 95% CI, 1.6 to 7.1) similar to that of current light smokers. Primary pipe or cigar smokers also showed increased risk (RR, 2.2; 95% CI, 0.6 to 8.0), but the number of subjects involved was small. The benefit of giving up smoking completely was seen within 5 years of quitting, with no further consistent decline in risk thereafter, but this was dependent on the amount of tobacco smoked. Light smokers (< 20 cigarettes/d) reverted to the risk level of those who had never smoked. Heavy smokers retained a more than twofold risk compared with never smokers (RR, 2.2; 95% CI, 1.1 to 4.3). The age-adjusted RR of stroke in those who quit smoking during the first 5 years of follow-up (recent quitters) was reduced compared with continuing smokers (RR, 1.8; 95% CI, 0.7 to 4.6 vs RR, 4.3; 95% CI, 2.1 to 8.8). The benefit of quitting smoking was observed in both normotensive and hypertensive men, but the absolute benefit was greater in hypertensive subjects. CONCLUSION: Smoking cessation is associated with a considerable and rapid benefit in decreasing the risk of stroke, particularly in light smokers (< 20 cigarettes/d); a complete loss of risk is not seen in heavy smokers. Switching to pipe or cigar smoking confers little benefit, emphasizing the need for complete cessation of smoking. The absolute benefit of quitting smoking on risk of stroke is most marked in hypertensive subjects.

Cerebrovascular Disorders↗
PubMed1995

National Medical Association Surgical Section position paper on violence prevention. A resolution of trauma surgeons caring for victims of violence.

The epidemic of intentional injury continues to be a leading cause of premature death in America. The ravages of violence are particularly devastating within the minority community. With this position paper from the Surgical Section of the National Medical Association (the country's oldest and largest organization of minority physicians), a group of trauma surgeons and surgical intensivists resolve to focus on underused violence prevention opportunities and to extend their spheres of influence beyond the walls of their institutions and emphasize violence prevention activities.

Humans↗
PubMed1995

Placebo-controlled trial of safety and efficacy of intraoperative controlled delivery by biodegradable polymers of chemotherapy for recurrent gliomas. The Polymer-brain Tumor Treatment Group.

Chemotherapy for brain tumours has been limited because of difficulty in achieving adequate exposure to the tumour without systemic toxicity. We have developed a method for local sustained release of chemotherapeutic agents by their incorporation into biodegradable polymers. Implantation of the drug-impregnated polymer at the tumour site allows prolonged local exposure with minimal systemic exposure. We conducted a randomised, placebo-controlled, prospective study to evaluate the effectiveness of biodegradable polymers impregnated with carmustine to treat recurrent malignant gliomas. In 27 medical centres, 222 patients with recurrent malignant brain tumours requiring re-operation were randomly assigned to receive surgically implanted biodegradable polymer discs with or without 3.85% carmustine. Randomisation balanced the treatment groups for all of the prognostic factors examined. Median survival of the 110 patients who received carmustine polymers was 31 weeks compared with 23 weeks for the 112 patients who received only placebo polymers (hazard ratio = 0.67, p = 0.006, after accounting for the effects of prognostic factors). Among patients with glioblastoma, 6-month survival in those treated with carmustine-polymer discs was 50% greater than in those treated with placebo (mortality = 32 of 72 [44%] vs 47 of 73 [64%], p = 0.02). There were no clinically important adverse reactions related to the carmustine polymer, either in the brain or systemically. Interstitial chemotherapy delivered with polymers directly to brain tumours at the time of surgery seems to be a safe and effective treatment for recurrent malignant gliomas.

Biodegradation, Environmental↗
PubMed1995

Risk factors for sudden cardiac death in middle-aged British men.

BACKGROUND: Risk factors specific to sudden cardiac death (SCD), ie, death within 1 hour after onset of symptoms, have been poorly identified, although recent findings from the present study incriminate heavy drinking and elevated heart rate. This paper examines the relations between a wide range of established and potential risk factors for ischemic heart disease (IHD) and SCD to identify independent risk factors for SCD and factors that might particularly or specifically relate to SCD. METHODS AND RESULTS: We present a prospective study of a cohort that was drawn from general practices in 24 British towns of 7735 middle-aged men who were followed up for 8 years. During 8 years of follow-up, the men experienced 488 major IHD events (nonfatal and fatal), of which 117 (24%) were classified as SCD. Age, preexisting IHD, arrhythmia, systolic blood pressure, blood cholesterol, elevated heart rate (> or = 90 beats per minute), physical activity (all, P < .05), and, to a lesser extent, smoking (P = .06), HDL cholesterol (P < .07), and elevated hematocrit (> or = 46%, P < .09) emerged as independent risk factors for SCD after adjustment for a wide range of factors. Diabetes was not found to be associated with SCD, and forced expiratory volume in 1 second, body mass index, white blood cell count, and antihypertensive drugs were not associated with risk of SCD after adjustment. When examined in relation to non-sudden IHD deaths and nonfatal myocardial infarction, elevated heart rate, heavy drinking, and arrhythmia emerged as factors that appear to be specific or particular to SCD. These three factors and age and blood cholesterol were associated with an increased risk of SCD in men both with and without preexisting IHD. Physical activity, systolic blood pressure, and current smoking were associated with SCD only in men without preexisting IHD. HDL cholesterol and hematocrit were strong predictors of SCD only in men with preexisting IHD. CONCLUSIONS: Three risk factors appear to be specific or particular to the risk of SCD, and these and other risk factors operate differently in patients with versus those without preexisting IHD. These findings have implications for the causes and prevention of SCD.

Adult↗
PubMed1995

Cell membrane dynamics and insulin resistance in non-insulin-dependent diabetes mellitus.

Insulin resistance in non-insulin-dependent diabetes mellitus (NIDDM) could be related to changes in cell membrane properties. We measured insulin sensitivity and mononuclear leucocyte membrane fluidity by fluorescence polarisation in fifteen NIDDM patients and twenty-one normal subjects. Core-region anisotropy was significantly lower in leucocytes from diabetic subjects (mean 0.164 vs 0.174, p < 0.001). Insulin sensitivity was positively correlated with such anisotropy before and after acute in-vitro insulin treatment. There was no difference in superficial membrane anisotropy. This study suggests that altered membrane dynamics in NIDDM may contribute to insulin resistance.

Cell Membrane↗
PubMed1995

Peripheral and hepatic insulin sensitivity in subjects with impaired glucose tolerance.

Recent evidence suggests that the postprandial hyperglycaemia in impaired glucose tolerance is primarily due to impaired suppression of basal hepatic glucose output. This in turn appears to be secondary to decreased first phase insulin secretion, although decreased hepatic insulin sensitivity, which is a feature of non-insulin-dependent diabetes mellitus, might also play a role. Eight mildly overweight subjects with impaired glucose tolerance and eight closely matched control subjects with normal glucose tolerance underwent an intravenous glucose tolerance test to assess first phase insulin secretion. Insulin sensitivity was examined by a 150-min hyperinsulinaemic-euglycaemic clamp. Somatostatin was infused from 150 min to suppress endogenous insulin secretion, and glucagon and insulin were replaced by constant infusion. Glucose with added dideuterated glucose (labelled infusion technique) was infused to maintain euglycaemia. First phase insulin secretion (delta 0-10 min insulin area divided by delta 0-10 min glucose area) was significantly decreased in the subjects with impaired glucose tolerance (median [range]: 1.2 [0.2-19.4] vs 9.1 [2.6-14.5] mU.mmol-1; p < 0.01). During the clamp, circulating insulin (93 +/- 8 [mean +/- SEM] and 81 +/- 10 mU.l-1) and glucagon (54 +/- 4 and 44 +/- 6 ng.l-1) levels were comparable. Total glucose disposal was decreased in subjects with impaired glucose tolerance (2.78 +/- 0.27 vs 4.47 +/- 0.53 mg.kg-1.min-1; p < 0.02), and was primarily due to decreased non-oxidative glucose disposal. However, hepatic glucose output rates were comparable during the clamp (0.38 +/- 0.10 and 0.30 +/- 0.18 mg.kg-1.min-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗
PubMed1995

The relationship of nutritional copper to the development of postmenopausal osteoporosis in rats.

Factors that influence tissue copper concentration include age, diet, hormones, and pregnancy. In this study we altered diet independently, hormone (estrogen) independently, and various combinations of diet and hormone in animals of the same age to study the effects of ovariectomy complicated with dietary copper deficiency; a deficiency that has been demonstrated to cause bone defects. Sprague-Dawley rats were placed on various combinations of copper deficient or enriched diets before and/or after ovariectomy to determine if copper deficiency aggravated osteoporosis and if return to a copper-adequate diet alleviated it. In this study, ovariectomy did induce an osteopenia that was characterized by decreased trabecular bone. This osteopenia was slightly more severe with copper deficiency, but was not necessarily alleviated by the return of normal copper levels to the diet.

Animals↗
PubMed1995

Obesity, insulin resistance, and its link to non-insulin-dependent diabetes mellitus.

Studies have shown that obese patients have a lower tissue response to insulin than lean individuals, suggesting that obesity promotes the development of insulin resistance. The mechanisms linking obesity and insulin resistance are not known. Obese patients have decreased glucose oxidation and increased lipid oxidation compared with lean individuals, and are hyperinsulinemic, which may result in downregulation of insulin receptors. Studies in healthy subjects have shown that increased plasma levels of nonesterified free fatty acids resulted in a decrease in peripheral insulin-induced glucose uptake. Obese patients have increased plasma levels of nonesterified free fatty acids, which may be involved in the development of insulin resistance. Patients with central obesity have a greater degree of peripheral insulin resistance and higher plasma insulin levels than patients with lower body obesity. Patients with non-insulin-dependent diabetes mellitus (NIDDM) who become obese have a further reduction in insulin sensitivity. Studies in Pima Indians have shown that adiposity is the most important predictor for NIDDM in children with at least one parent who have diabetes. Insulin sensitivity improves with weight loss in obese patients.

Diabetes Mellitus, Type 2↗
PubMed1995

Treating the patient who is disfigured by head and neck cancer.

A 46-year-old man with laryngeal carcinoma was admitted to the medical service for lethargy. The medical team requested a psychiatric consultation to assist with the patient's depression, substance abuse, and noncompliance. The case is presented and discussed with reference to the issues of depression, disfigurement, dysfunction, and substance abuse in the patient with head and neck cancer.

Alcoholism↗
PubMed1995

Laterality of visuo-spatial attention in acute and chronic schizophrenia, major depression and in healthy controls.

Previous studies have suggested that schizophrenia is characterized by an asymmetry of visuo-spatial attention, in particular that acute unmedicated schizophrenics demonstrate relative inattention to right hemispace, whereas chronically medicated patients demonstrate the opposite pattern. In the present study, 30 unmedicated schizophrenic patients, 32 chronically medicated schizophrenic patients, 30 patients suffering from major depression and 60 healthy controls were assessed using two measures of hemispatial attentional neglect, namely letter and star cancellation. The results demonstrated that the chronic schizophrenic group made more total omissions for star cancellation (in both right and left hemispace), but that there was no difference between the groups in terms of omission asymmetry for either letter or star cancellation.

Adult↗
PubMed1995

Weight change and risk of heart attack in middle-aged British men.

BACKGROUND: Both weight gain and weight loss have been associated with increased risk of cardiovascular disease mortality in recent studies from the US. This finding has led to concern and uncertainty about appropriate advice for overweight and obese subjects. METHODS: In a prospective study of cardiovascular disease, the relationship between weight change over a 5-year period and subsequent risk of a heart attack during a further 6.5 year follow-up was examined in 7100 middle-aged British men. RESULTS: Over half of the men remained stable (< 4% change in bodyweight) and served as the reference group; 31% gained weight and 13% lost weight. The 6445 men free from a history of coronary heart disease experienced 318 heart attacks, fatal and non-fatal, during the 6.5 years. Men who gained 4-10% bodyweight had the lowest rate of heart attack, although this was not significantly different from the stable group. The men who lost weight had an increased risk of heart attack, which after adjustment (for age, recall of doctor-diagnosed hypertension and diabetes and other coronary risk factors i.e. serum total cholesterol, blood pressure, social class, initial body mass index (BMI) and lung function (FEV1), and smoking status at screening and 5 years later), was of a similar level of risk to the stable group. The men who gained > 10% bodyweight had a significantly increased risk of a heart attack after the above adjustment (P < 0.05). When the effect of weight change was examined according to initial BMI, those men with a BMI < 25 kg/m2 who lost weight had a marginally increased relative risk of heart attack after full adjustment (P = 0.06), while men who were overweight (BMI 25-27.9 kg/m2) or obese (BMI > or = 28 kg/m2) showed no benefit from weight loss. A small amount of weight gain (4-10%) in the overweight or obese men was associated with decreased risk, whereas considerable weight gain (> 10%) was associated with increased risk, both findings reaching statistical significance in the overweight men (P < 0.05 and P < 0.001 respectively). CONCLUSIONS: Considerable weight gain (> 10%) in middle-aged men is associated with increased risk of a heart attack, but weight loss does not appear to reduce risk even in the overweight or obese.

Adult↗