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Biomedical subjects

M Woods

Publications and source records attributed to M Woods.

At least 19 recordsLinked to original sources

Enhancing the level of nutrition education at Tufts University's Medical and Dental Schools.

The current medical and dental curricula at Tufts were evaluated to ascertain the breadth and depth of their nutrition programs. The program, which both schools plan to initiate, to enhance the level of nutrition education involves (1) development of nutrition units for the first and second year, (2) expansion of required nutrition courses in the second year, (3) diet lunches in the third year introducing the role of nutrition in the clinical setting, and (4) nutrition rounds in the fourth year. A combined medical-dental seminar will be presented each year. At the end of the five-year funding period, it is anticipated that a manual will be available to all medical and dental schools that includes (1) nutrition units, (2) methods of dietary assessment in medical-dental practices, (3) nutrition interaction for the prevention of chronic disease in medical-dental practices, and (4) nutrition support for chronic disease and cancer, and case studies on nutrition and disease. The success of this program will be evaluated on the basis of goals and a national nutritional literacy exam.

Boston

Antibiotic prophylaxis for cardiothoracic operations. Meta-analysis of thirty years of clinical trials.

Antistaphylococcal penicillins and first-generation cephalosporins have traditionally been the prophylactic antibiotics of choice for patients undergoing cardiothoracic operations. Recently published studies have claimed improved outcomes with respect to postoperative wound infection when second-generation cephalosporins were used for prophylaxis. The purpose of this study was to critically review the infectious outcomes of prospective, randomized, and controlled studies of cardiothoracic surgery prophylaxis by means of meta-analytic techniques. For each of 28 studies meeting the meta-analysis entry criteria, odds ratios with 95% confidence intervals were calculated to compare the prophylactic efficacy of the antibiotic regimens. Odds ratios were then pooled, and a summary odds ratio was calculated for each pairing of antibiotic treatments. Placebo-controlled trials of cardiothoracic prophylaxis demonstrated a consistent benefit to the administration of antibiotic prophylaxis, with an approximate fivefold reduction in wound infection rate. The second-generation cephalosporins, cefamandole and cefuroxime, performed better than cefazolin, with an approximate one and one-half-fold reduction in wound infection rate. Administration of prophylaxis beyond 48 hours was not associated with improved infectious outcomes.

Anti-Bacterial Agents

Increased sensitivity of guinea pig gallbladder in vitro to bradykinin.

Bradykinin evoked concentration dependent contractions of guinea pig gallbladder smooth muscle strips in vitro. Responses to kinins increase over three hours of incubation. Induction of a B1-mediated action, waning activity of endogenous kininase(s) and involvement of eicosanoids as mediators have been investigated as potential contributing mechanisms to the four-fold, time dependent increase in response of this tissue to bradykinin.

Animals

Motivational effect of cholesterol measurement in general practice health checks.

A randomized trial was conducted in five general practices in and around Aylesbury, Buckinghamshire to assess the motivational effect of cholesterol measurement on compliance with advice to reduce dietary fat intake and to stop smoking. The advice was given by practice nurses during health checks for cardiovascular risk factors. A total of 578 patients were recruited to the study and randomized into two groups. Both groups were given the same advice and were followed up after a median of three months, but the intervention group was also given immediate feedback on their cholesterol concentration. Follow up was completed for 88.2% of subjects, and those who were not followed up were assumed not to have changed their behaviour. The mean fall in total cholesterol at follow up was 0.11 mmol l-1 (95% confidence interval 0.03 to 0.18) in the intervention group who were told their cholesterol result and 0.02 mmol l-1 (95% CI -0.06 to 0.10) in the control group who were not. The proportion of smokers who were not smoking at follow up was 10.7% and 10.1% in the two groups, respectively. Patients in the intervention group with an initial total cholesterol level of 6.50 mmol l-1 or greater showed a mean fall of 6.2% in cholesterol level whereas those with an initial cholesterol level of less than 5.20 mmol l-1 experienced a mean increase of 3.6%, but as differences of this magnitude were also seen in the control group they probably reflect regression to the mean rather than an effect of knowledge of cholesterol level.(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude to Health

Desensitization of atriopeptin stimulated accumulation and extrusion of cyclic GMP from a kidney epithelial cell line (MDCK).

Atriopeptin caused dose- (EC50 ca. 2 x 10(-8) M) and time-dependent increases in the intracellular concentration of cyclic GMP in the MDCK kidney epithelial cell line; an effect potentiated by the phosphodiesterase inhibitor, IBMX. The atriopeptin-catalysed increase in cyclic GMP was transient and reached a maximum some 10-20 min after challenge of cells with atriopeptin. The basis for the transience of this increase was shown to be due to the desensitization of guanylate cyclase coupled with extrusion of cyclic GMP from the cells and the degradation of cyclic GMP by phosphodiesterase activity. Atriopeptin-catalysed extrusion of cyclic GMP was time- and dose-(EC50 ca. 1.5 x 10(-8) M) dependent and was inhibited by probenecid but not by high external cyclic GMP concentrations. The extrusion process underwent apparent desensitization as did guanylate cyclase with similar half lives (T1/2 of ca. 20 min). Desensitization was dose-dependent upon atriopeptin and did not appear to be mediated by elevated cyclic GMP concentrations as pre-incubation with 8-bromo cyclic GMP did not cause desensitization and the half-times for desensitization were similar whether or not IBMX was present. The majority of the cyclic nucleotide phosphodiesterase activity was found in the cytosol fraction of the cells and could be separated into two cyclic AMP specific forms and two cyclic GMP preferring forms.

2',3'-Cyclic-Nucleotide Phosphodiesterases

Food use and health effects of soybean and sunflower oils.

This review provides a scientific assessment of current knowledge of health effects of soybean oil (SBO) and sunflower oil (SFO). SBO and SFO both contain high levels of polyunsaturated fatty acids (PUFA) (60.8 and 69%, respectively), with a PUFA:saturated fat ratio of 4.0 for SBO and 6.4 for SFO. SFO contains 69% C18:2n-6 and less than 0.1% C18:3n-3, while SBO contains 54% C18:2n-6 and 7.2% C18:3n-3. Thus, SFO and SBO each provide adequate amounts of C18:2n-6, but of the two, SBO provides C18:3n-3 with a C18:2n-6:C18:3n-3 ratio of 7.1. Epidemiological evidence has suggested an inverse relationship between the consumption of diets high in vegetable fat and blood pressure, although clinical findings have been inconclusive. Recent dietary guidelines suggest the desirability of decreasing consumption of total and saturated fat and cholesterol, an objective that can be achieved by substituting such oils as SFO and SBO for animal fats. Such changes have consistently resulted in decreased total and low-density-lipoprotein cholesterol, which is thought to be favorable with respect to decreasing risk of cardiovascular disease. Also, decreases in high-density-lipoprotein cholesterol have raised some concern. Use of vegetable oils such as SFO and SBO increases C18:2n-6, decreases C20:4n-6, and slightly elevated C20:5n-3 and C22:6n-3 in platelets, changes that slightly inhibit platelet generation of thromboxane and ex vivo aggregation. Whether chronic use of these oils will effectively block thrombosis at sites of vascular injury, inhibit pathologic platelet vascular interactions associated with atherosclerosis, or reduce the incidence of acute vascular occlusion in the coronary or cerebral circulation is uncertain. Linoleic acid is needed for normal immune response, and essential fatty acid (EFA) deficiency impairs B and T cell-mediated responses. SBO and SFO can provide adequate linoleic acid for maintenance of the immune response. Excess linoleic acid has supported tumor growth in animals, an effect not verified by data from diverse human studies of risk, incidence, or progression of cancers of the breast and colon. Areas yet to be investigated include the differential effects of n-6- and n-3-containing oil on tumor development in humans and whether shorter-chain n-3 PUFA of plant origin such as found in SBO will modulate these actions of linoleic acid, as has been shown for the longer-chain n-3 PUFA of marine oils.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals

Effect of long-term fish oil supplementation on vitamin E status and lipid peroxidation in women.

Fifteen young (22-35 y) and 10 older (51-71 y) women received six capsules of fish oil (Pro-Mega)/d, providing a total of 1,680 mg eicosapentaenoic (EPA), 720 mg docosahexaenoic (DHA), 600 mg other fatty acids, and 6 IU vitamin E. Blood was collected before and after 1, 2 and 3 mo of supplementation. Compliance was confirmed by the significant increase in plasma EPA and DHA in all women. Older women had a significantly higher increase in EPA and DHA than did young women (10-fold increases in EPA and 2.5-fold increases in DHA vs. 8-fold in EPA and 2-fold in DHA for older and young women, respectively). The decrease in the arachidonic acid:EPA ratio was more dramatic in the older women. Plasma total triglycerides (TG) decreased significantly, and the ratio of polyunsaturated fatty acids to saturated fatty acids was significantly (P less than 0.01) increased. Plasma vitamin E levels did not change significantly after supplementation; however, after 3 mo of supplementation by young women, plasma vitamin E was significantly lower than after 1 mo. The vitamin E: TG ratio was significantly increased and vitamin E:(EPA + DHA) significantly decreased. All women showed a significant increase in plasma lipid peroxide through mo 2 of supplementation. After 2 mo, older women had significantly higher lipid peroxide levels than young women. The lipid peroxide:TG ratio, which declined by mo 3, was still significantly higher than baseline. These data indicate that although long-term fish oil supplementation may be beneficial in reducing plasma total TG, susceptibility of plasma lipids to free radical attack is potentiated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Blot-sequencing of antibodies: application to analysis of V gene usage among anti-steroid monoclonal antibodies.

Automated gas-phase protein sequencing has been used to characterize variable regions of antibody heavy and light chains separated by SDS-polyacrylamide gel electrophoresis (PAGE) and electroblotted onto Immobilon polyvinylidene difluoride membranes ('blot-sequencing'). Starting from 100 micrograms of antibody, 20 or more residues of N-terminal VH and VL sequences can regularly be obtained, which is often sufficient to assign the V region to a known family or subgroup. We have applied the blot-sequencing method to analysis of VH and VL usage among a panel of monoclonal anti-steroid antibodies, namely anti-progesterone, anti-pregnanediol, anti-estrone and anti-testosterone. The results demonstrate restricted, repetitive usage of VL subgroups and VH families related to anti-steroid specificities. VL regions of the VK1 group were particularly associated with anti-progesterone, VK21 with anti-estrone, and VK8 and VK9 with anti-pregnanediol. VH regions of anti-progesterone antibodies were all derived from the VHVGAM3.8 family; anti-estrone and anti-pregnanediol antibodies were derived from the VH7183 and VH36-60 families. The latter two families appear to characterize antibodies raised against steroids conjugated to proteins via a sugar bridge. Differences in VH/VL combination were associated with diversity of antibody specificity. In order to extend the sequence data obtained by this technique and confirm family assignments, we have shown that internal V-region sequences can be obtained by limited chemical cleavage of whole antibody with cyanogen bromide, followed by separation of individual fragments by SDS-PAGE and blot-sequencing.

Amino Acid Sequence

Validation of a self-administered diet history questionnaire using multiple diet records.

The validity of a self-administered diet history questionnaire has been estimated using as the reference data the mean of three 4-day diet records collected over the year prior to the administration of the questionnaire, in 1985-1986. Subjects were women ages 45-70 years, participants in the Women's Health Trial Feasibility Study, a multi-center clinical trial in which some women were randomized to be taught to adopt and maintain a low-fat diet, while others maintained their usual diet. The questionnaire produced group mean nutrient estimates closely approximating the values obtained by three 4-day records, e.g. in the usual-diet group, 37.7% of calories from fat by both food records and by questionnaire, and in the low-fat group, 21.3% of calories from fat by food records and 23.7% of calories from fat by questionnaire. Correlations between questionnaire and diet records for per cent of calories from fat were 0.67 and 0.65 respectively in the two groups; most correlations were in the 0.5-0.6 range, and were similar to those achievable by a single 4-day food record.

Aged

Food uses and health effects of corn oil.

This review of corn oil provides a scientific assessment of the current knowledge of its contribution to the American diet. Refined corn oil is composed of 99% triacylglycerols with polyunsaturated fatty acid (PUFA) 59%, monounsaturated fatty acid 24%, and saturated fatty acid (SFA) 13%. The PUFA is linoleic acid (C18:2n-6) primarily, with a small amount of linolenic acid (C18:3n-3) giving a n-6/n-3 ratio of 83. Corn oil contains a significant amount of ubiquinone and high amounts of alpha- and gamma-tocopherols (vitamin E) that protect it from oxidative rancidity. It has good sensory qualities for use as a salad and cooking oil. Corn oil is highly digestible and provides energy and essential fatty acids (EFA). Linoleic acid is a dietary essential that is necessary for integrity of the skin, cell membranes, the immune system, and for synthesis of icosanoids. Icosanoids are necessary for reproductive, cardiovascular, renal, and gastrointestinal functions and resistance to disease. Corn oil is a highly effective food oil for lowering serum cholesterol. Because of its low content of SFAs which raises cholesterol and its high content of PUFAs which lowers cholesterol, consumption of corn oil can replace SFAs with PUFAs, and the combination is more effective in lowering cholesterol than simple reduction of SFA. PUFA primarily lowers low-density-lipoprotein cholesterol (LDL-C) which is atherogenic. Research shows that PUFA has little effect on high-density-lipoprotein cholesterol (HDL-C) which is protective against atherosclerosis. PUFA generally improves the ratio of LDL-C to HDL-C. Studies in animals show that PUFA is required for the growth of cancers; the amount required is considered to be greater than that which satisfies the EFA requirement of the host. At this time there is no indication from epidemiological studies that PUFA intake is associated with increased risk of breast or colon cancer, which have been suggested to be promoted by high-fat diets in humans. Recommendations for minimum PUFA intake to prevent gross EFA deficiency are about 3% of energy (en%). Recommendations for prevention of heart disease are 8-10 en%. Consumption of PUFA in the United States is 5-7 en%. The use of corn oil to contribute to a PUFA intake of 10 en% in the diet would be beneficial to heart health. No single source of salad or cooking oil provides an optimum fatty acid (FA) composition. Many questions remain to be answered about the relation of FA composition of the diet to various physiological functions and disease processes.

Animals

Results of a randomized feasibility study of a low-fat diet.

A 2-year randomized clinical trial was conducted to test whether free-living women aged 45 to 69 years can reduce the fat content of their diet from the typical US level of approximately 39% to 20% of energy from fat, using readily available foods, when given nutritional and behavioral counseling and social support. Three clinical units randomized 303 selected volunteers into intervention (low-fat eating plan) or control (customary diet) groups. The two groups were comparable at baseline. The intervention group received nutrition instruction and behavioral counseling largely in permanent groups of 12 to 15 participants meeting weekly, then biweekly, and finally monthly. At 6 months, they had substantially reduced the mean proportion of total energy from fat from 39.1% to 20.9%, compared with the control group's nonsignificant reduction from 39.0% to 38.1%. At 12 and 24 months, they sustained the reduction of energy from fat. Weight loss and plasma cholesterol level changes in the intervention group supported the self-recorded dietary intake changes. Attendance at intervention sessions averaged 75% during the first 6 months and, subsequently, 60% to 70%. Four-day food records for the randomized women were obtained at 6 and 12 months from approximately 95% and at 24 months from 87%. A clinical trial of a low-fat diet is feasible in women.

Aged

MMPI F-K index among hospitalized Vietnam veterans.

The F-K index of the MMPI has been used as a marker of symptom overreporting. One population for which previous research has shown this pattern is Vietnam in-country veterans with PTSD. This study assessed the F-K index on 515 inpatients: 329 Vietnam in-country and 186 Vietnam-era patients. Normative data on psychiatric inpatients were presented. Also, a special MMPI subscale (MMPI-PTSD), a measure to identify PTSD among these veterans, was used. Results showed that all Vietnam veterans, especially in-country veterans, overreport symptoms to a high degree. The overall mean for in-country vets was 7.3. Also, when the special MMPI-PTSD subscale was used, a vast majority of in-country veterans who were in the PTSD range had high F-K index scores. Dissimulation as a symptom of PTSD was discussed.

Adult

Plasma lipoprotein cholesterol and endogenous sex hormones in healthy young women.

Relationships between plasma levels of lipoproteins and sex hormones were studied in 24 healthy premenopausal women with no risk factors for coronary heart disease. The women were carefully selected to remove the effects of other environmental factors, such as smoking, drugs, alcohol, and exercise, which are known to influence lipid metabolism. They all ate precisely the same Western-style diet for 1 to 2 weeks before blood samples were obtained in the follicular phase of their menstrual cycle. After adjusting for other hormones by multiple regression, significant positive partial correlations were seen between high density lipoprotein cholesterol (HDL-C) and protein bound estradiol (r = .57, P = .02), as well as between very low density lipoprotein cholesterol (VLDL-C) and protein bound estradiol (r = .63, p = .01). A significant negative partial correlation was seen between VLDL-C and free estradiol (r = -.65 P = .01). Conversely, low density lipoprotein cholesterol (LDL-C) levels were negatively correlated with protein bound estradiol (r = -.77, P less than .001) and positively correlated with free estradiol (r = .71, P less than .001). No associations between plasma lipoproteins and testosterone were seen; however, androstenedione was positively correlated with VLDL-C (r = .59, P = .01). These findings show a close link between plasma lipoproteins and sex hormones, and may help to explain the lower risk of coronary heart disease in women.

Adult