Exercise and cardiovascular disease: a new perspective

The oxidation of low density lipoprotein (LDL) has been suggested as a key event in atherogenesis. Paradoxically, exercise, which imposes an oxidative stress, is an important deterrent of cardiovascular disease. In study 1 the oxidizability of LDL was enhanced in exercisers compared with sedentary controls. The lag time of isolated LDL subjected to copper-induced in vitro oxidation was significantly shortened in the exercisers compared with sedentary subjects. This increased sensitivity was not due to a decreased presence of vitamin E. Instead, these findings suggested that the LDL of exercisers may contain increased amounts of preformed lipid peroxides, which account for the increased oxidizability. In study 2, a group x sex ANOVA revealed that male exercisers had a significantly longer mean lag time than male sedentary subjects and that females had similar mean lag times regardless of exercise group. This remained the case when statistical adjustment was made for age, body mass index, blood lipid levels, LDL, and plasma alpha-tocopherol levels. Study 1 exercisers had been in training for a shorter time (< 1 year) than study 2 exercisers (> 2 years). These findings suggest that truly "chronic" exercise (aerobic intensity over several months) decreases the susceptibility of a male exerciser's LDL to undergo oxidation. Conversely, regular aerobic stress during an overall shorter time span creates a more oxidative environment in the body, thus increasing the susceptibility of LDL to undergo oxidation. The oxidative stress of aerobic exercise does not appear to adversely affect the oxidizability of LDL in women.     

Serum lipids and cardiovascular reactivity to stress

Several studies have reported an association between serum lipid levels and cardiovascular reactivity to laboratory stressors. Their findings, however, are equivocal. The inconsistencies may be due to shortcomings such as the small number of subjects, the inclusion of patient groups, no control for medication, and no control for age effects. Two studies are presented investigating the relationship in large groups of adolescent and middle-aged males and females. Cholesterol, triglycerides and HDL were measured. Subjects were exposed to mental stressors, and in one study also to a cold pressor test. In addition to heart rate and blood pressure, in one study impedance cardiography was used to measure pre-ejection period, stroke volume and total peripheral resistance. Canonical correlation analysis suggested an association between triglycerides and decreased cardiac reactivity to mental stressors in middle-aged females. Trends in the same direction were found in both middle-aged males and females with respect to reactivity to the cold pressor. These associations, however, were not confirmed when the extreme deciles of the triglyceride distributions were compared with respect to stress reactivity. The fact that associations were completely absent in youngsters but sometimes showed up in older persons suggested an age dependency of the association. In post hoc analyses, indeed, some evidence was found for stronger cardiac responsivity being associated with cholesterol specifically in relatively older males. In females, in contrast to this, the association between triglycerides and cardiac responsivity was stronger in the younger group. More detailed measurement techniques, of specifically vascular processes, may be needed to explore further the effects of sex and age on the association between lipids and stress reactivity.     

Diet, lipids, and coronary heart disease.

Contends that R. M. Kaplan (see record 1985-12441-001) presented a one-sided debate on the diet/heart controversy. It is suggested, based on studies cited, that preventive efforts recognizing dietary cholesterol's primary contribution to death and disability must be implemented. Answers to 5 questions about cholesterol presented to a National Institutes of Health panel are appended. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cholesterol, endothelial function and cardiovascular disease

Poster presentations have proved to be a popular method of displaying information at conferences, and are being used increasingly as a teaching method. Innovative strategies for teaching and assessing research need to facilitate students' achievement of research skills required for practice. These are outlined by the Department of Health, and emphasize the development of research literacy. Using the poster presentation as a teaching and assessing strategy on diploma level courses (Project 2000 and ENB 870 introduction to the Understanding and Application of Research) has proved to be valuable in developing vital research awareness skills and in harnessing enthusiasm for research. Students imply a sense of achievement gained through the process of developing the poster and the production of the poster itself. Herein lies the value of the poster presentation, for it allows the development of crucial research literacy skills which can be widely used in professional practice and future professional education.     

Soy protein, isoflavones and cardiovascular disease risk

Since the early 1940s, scientists have examined the effect of soy protein on blood cholesterol concentrations. Although studies in animals have suggested that soy protein lowers blood cholesterol concentrations, similar studies in humans have yielded less consistent results. The presence or absence of the soybean isoflavone fraction may be a confounding factor. This fraction, consisting primarily of genistein, daidzein and glycetein, has been shown to have a hypocholesterolemic effect in animals and humans. Potential mechanisms by which soy protein and/or isoflavones induce lowering of blood cholesterol concentrations include thyroid status, bile acid balance and the estrogenic effects of genistein and daidzein. Some studies have suggested that isoflavones exhibit antioxidant properties and have favorable effects on arterial compliance. In addition to the aforementioned potential beneficial effects, the increased consumption of products containing soy protein may displace foods relatively high in saturated fat and cholesterol from the diet and hence have an indirect blood cholesterol-lowering effect.     

Exercise, smoking cessation, and short-term changes in serum lipids in women: a preliminary investigation

PURPOSE: This study investigated the combined effects of exercise and smoking cessation on serum lipids. METHODS: Eighteen female smokers quit smoking using standard behavioral methods combined with exercise (N = 9) or with a nonexercise contact time control (N = 9). The smoking cessation program for both groups consisted of 12 weekly 1-h behavioral modification sessions held over 12 wk. Exercise training consisted of three supervised 45-min sessions per week for 12 wk. Contact control consisted of three health education lectures/discussions per week for 12 wk. Fitness (estimated VO2 peak), dietary variables, and fasting serum lipids and lipoproteins were assessed before and at the end of treatment. VO2 peak increased in the exercise subjects compared with the controls. RESULTS: Total caloric intake as well as total fat and carbohydrate increased significantly after smoking cessation in the controls, but there were no dietary changes in the exercise group. high density lipoprotein (HDL)-C2 increased (7.6 mg x dL(-1), P < 0.01) in the exercise group, whereas the increases in HDL and its subfractions did not attain statistical significance in the contact control group. Total cholesterol, low density lipoprotein (LDL)-C, and triglycerides did not change in either group. CONCLUSIONS: We conclude that exercise training magnifies the increase in HDL-C that usually occurs with smoking cessation.     

Thrombosis and cardiovascular disease

The use of combinatorial chemistry for the generation of new lead molecules is now a well established strategy in the drug discovery process. Central to the use of combinatorial chemistry is the design and availability of high quality building blocks which are likely to afford hits from the libraries that they generate. Herein we describe "RECAP" (Retrosynthetic Combinatorial Analysis Procedure), a new computational technique designed to address this building block issue. RECAP electronically fragments molecules based on chemical knowledge. When applied to databases of biologically active molecules this allows the identification of building block fragments rich in biologically recognized elements and privileged motifs and structures. This allows the design of building blocks and the synthesis of libraries rich in biological motifs. Application of RECAP to the Derwent World Drug Index (WDI) and the molecular fragments/ building blocks that this generates are discussed. We also describe a WDI fragment knowledge base which we have built which stores the drug motifs and mention its potential application in structure based drug design programs.     

Hyperlipidaemia and cardiovascular disease

Seasonal variations in mood and behavior (seasonality) and seasonal affective disorder (SAD) have been attributed to seasonal fluctuations in brain serotonin (5-HT). the short (s), as opposed to the long (l), allele of the 5-HT transporter linked polymorphism (5-HTTLPR) has been associated with neuroticism and depression. We hypothesized that this short allele would also be associated with SAD and with higher levels of seasonality. Ninety-seven SAD patients and 71 non-seasonal healthy controls with low seasonality levels were genotyped for 5-HTTLPR and compared statistically. Patients with SAD were less likely to have the l/l genotype (27.8% vs 47.9%; P < 0.01) and more likely to have the s allele (44.8% vs 32.4%; P < 0.02) as compared to controls. The three 5-HTTLPR genotypes were also differentially distributed in patients and controls (P < 0.03). The SAD patients with the l/l genotype had a lower mean seasonality score than did patients with the other two genotypes (mean +/- s.d. = 15.3 +/- 2.8 vs 17.1 +/- 3.4 respectively; P < 0.02). The 5-HTTLPR short allele contributes to the trait of seasonality and is a risk factor for SAD, providing further evidence for a relationship between genetic variation in the 5-HT transporter (5-HTT) and behavior.     

Hyperlipidaemia and cardiovascular disease

OBJECTIVE: The aim of the study is to investigate the relationship between urinary cytology, traditional indexes of malignancy of bladder carcinoma and DNA-ploidy (diploid, near-diploid, aneuploid). METHODS: 52 specimens of bladder cancers (transitional cell carcinoma) were obtained from 46 patients at TURB and from 6 patients at radical cystectomy. In every specimen the nuclear content of DNA was investigated using the cytofluorimetric method. Cells were processed in standard fashion for flow cytometry with propidium iodide staining; cellular suspension was obtained mechanically. Peripheral blood lymphocytes were used as diploid standard. Bladder cytology was performed in every patient. RESULTS: A relationship between DNA-ploidy and histological malignancy was observed. The largest portion of near-diploid neoplasm was observed in stage T1, grade G2 malignancies. In some cases negative bladder cytology occurred together with aneuploid DNA content, whilst in other cases positive bladder cytology occurred together with diploid DNA content. In consequence there is not always a relationship between bladder cytology and DNA-ploidy. CONCLUSIONS: Since observed correlations may point out some neoplasms with particular biological behaviour, follow-up of near-diploid malignancies is of great interest.     

Vascular disease and lipids in diabetes

Atherosclerosis kills more patients with diabetes than all other causes combined. Aggressive reversal and treatment of dyslipidemias is the only proven prevention for coronary events in the patient with type 2 diabetes. Glycemic control with diet, oral hypoglycemic agents, and insulin, when necessary, is often only partially effective in normalizing lipid values in type 2 diabetes. Intensive treatment with lipid-regulating agents, particularly HMG-CoA reductase inhibitors, is often necessary to normalize diabetes-associated dyslipidemias. HMG-CoA reductase inhibitors are also the only agents thus far shown in prospective multicenter trials to reduce the risk of coronary events in diabetic patients.