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Biomedical subjects

J Raison

Publications and source records attributed to J Raison.

31 records · Page 2Linked to original sources
PubMed1988

[Regional hemodynamics of the forearm. Comparison between obese and non-obese hypertensive patients].

Forearm hemodynamics using pulsed Doppler flowmetry were studied in 83 men: 15 non-obese and 8 obese normotensive subjects; and 30 non-obese and 30 obese hypertensive patients. Mean ages were similar in the four subgroups. The blood pressure of normotensives and hypertensives was identical in obese and non-obese subjects. Blood flow expressed in ml/mn was significantly higher in obese subjects whether normotensive or hypertensive. However, when blood flow was expressed per unit liter of forearm volume, it was similar in the four subgroups. Forearm vascular resistance, whether expressed as absolute of normalized values, was significantly higher (p less than 0.001) in non-obese hypertensives. When obese and non-obese hypertensives were compared, the former were characterized by higher values of blood velocity and blood flow, and lower values of vascular resistance, whether absolute or normalized values were used. The present study shows that: (i) forearm vascular resistance in hypertensives is increased exclusively in non-obese subjects, and (ii) obese hypertensives, when compared with non-obese hypertensives, are characterized by a hyperkinetic forearm circulation.

Adult↗
PubMed1988

Regional differences in adipose tissue lipoprotein lipase activity in relation to body fat distribution and menopausal status in obese women.

Adipose tissue lipoprotein lipase (LPL) activity was determined in the abdominal and femoral regions in 25 pre- and 25 post-menopausal obese women, matched for body mass index and fat distribution. LPL activity was not different in pre- and post-menopausal women. Regional differences of the same magnitude were observed in pre- and post-menopausal women with femoral obesity. Such differences were not found in women with abdominal obesity either pre- or post-menopausal. Furthermore the abdominal/femoral ratio of LPL activity was positively correlated (P less than 0.05) to waist/hip ratio, independently of age, body mass index, fat cell size ratio and menopausal status. These data indicate that in obese women the regional differences in LPL activity are related to body fat distribution. The menopausal status does not seem to be a sufficient and necessary condition to abolish the typical female regional differences in LPL activity in adipose tissue from obese women.

Abdomen↗
PubMed1987

[Relation between adipose tissue distribution and and circulating lipids in obese women].

Adipose tissue distribution was determined in 50 pre--or post--menopausal women by measuring the waist/hip and arm/thigh circumference ratios and the brachial-femoral adipo-muscular ratio. These three ratios correlated with plasma triglycerides levels irrespective of the women's age and degree of obesity. Total cholesterol, LDL-cholesterol and HDL-cholesterol were related to age and not to weight or adipose tissue distribution. Compared to pre-menopausal women with the same weight excess, post-menopausal women had a more android type of body fat distribution and higher plasma triglycerides and total cholesterol values. The influences of age and menopause are difficult to separate, since the three distribution ratios are age-related. The correlation between plasma triglycerides and adipose tissue distribution in obese women reflects the metabolic consequences of an abdominal predominance of fat.

Adult↗
PubMed1987

[Influence of the distribution of body fat on vascular risk].

The metabolic and cardiovascular complications of obesity are dependent upon the distribution of body fat excess: predominantly abdominal or "android" obesity is more pathogenic than "gynoid" obesity which predominates in the lower part of the body. Adipose tissue overloads localized to the abdomen are associated with hypermortality from vascular diseases, even in patients who are not overweight. The metabolic characteristics of abdominal adipocytes, which have increased lipolytic capacity, might account for this situation, as they would facilitate hyperinsulinism, insulin resistance and such-metabolic disturbances as arterial hypertension, diabetes mellitus and dyslipidemia. Androgens seem to play a key role in the development of obesity morphotypes. These notions have important practical applications: an excess of body fat is not necessarily pathogenic; as regards vascular and metabolic risks, body fat distribution seems to be more important than overweight.

Abdominal Muscles↗
PubMed1986

Extracellular and interstitial fluid volume in obesity with and without associated systemic hypertension.

Fluid volumes and cardiac and renal hemodynamics were investigated in 44 obese men, 22 with normal blood pressure and 22 with sustained essential hypertension. For the same degree of obesity hypertensive patients had a higher value in extracellular (p less than 0.05) and interstitial fluid (p less than 0.01) volumes than normotensive subjects, while plasma volume, total body water, body cellular water, cardiac output, renal blood flow and glomerular filtration rate were similar. For the same level of blood pressure, the expansion of extracellular and interstitial fluid volume paralleled the degree of obesity. Thus, obese patients with hypertension have an absolute increase in extracellular and interstitial fluid volumes. The increase was related both to the degree of overweight and to the mechanisms of hypertension.

Adult↗
PubMed1986

[Metabolism of sex hormones and adipose tissue].

Adipose tissue is a catchment area for storing, converting and releasing the sex hormones. The role of adipose tissue in the general metabolism of endogenous and exogenous steroids deserves to be considered seeing how big the volume of fat is in the human body. The fatty pool of sex steroids seems to be greater than the plasma pool. Hormones which have been stored can be released by adipocytes into the general circulation even if they have been converted while in the adipocytes. Similarly, androgens are changed by adipose tissue into oestrogens by aromatisation and are liberated. This extraglandular production of oestrogens can have clinical and pathological consequences.

Adipose Tissue↗
PubMed1984

Adipose tissue cellularity and hemodynamic indexes in obese patients with hypertension.

Fat-cell weight, fat-cell number, and hemodynamic indexes were determined in 25 obese men with sustained elevation of BP. Fat-cell weight (and not fat-cell number) was positively correlated with overweight (r = .51) and mean arterial pressure (MAP) (r = .57) in basal conditions. After body weight reduction, BP decreased significantly through a decrease in cardiac index due to a predominant decrease in heart rate. Simultaneously, fat-cell weight decreased significantly. The ratio between the change in BP and the change in body weight, ie, the ability to decrease pressure per unit weight loss, was positively related to the level of initial BP (r = .80) and reached a plateau above 120 mm Hg of the initial MAP. We suggest that, in patients with obesity and hypertension, high BP is associated with hypertrophic obesity, and after body weight reduction, the simultaneous decrease in BP, heart rate, and fat-cell weight could be mediated by neurogenic mechanisms.

Adipose Tissue↗
PubMed1983

Biological membranes are rich in low-frequency motion.

Using 13C cross-polarization NMR techniques, we have found that the effect of protein on the dynamics of the hydrocarbon interior of a series of biological membranes is to depress the intensity of motion on the nanosecond timescale (i.e., T1 becomes longer) and to enhance the intensity of motion on the timescale of tens of microseconds (i.e., T1p becomes shorter.)

Animals↗
PubMed1983

Intravascular volume, extracellular fluid volume, and total body water in obese and nonobese hypertensive patients.

Intraarterial blood pressure, plasma volume, extracellular and interstitial (IFV) fluid volumes, and total and intracellular (IBV) body water were evaluated in 50 men: 16 obese hypertensive patients, 16 nonobese hypertensive patients, and 18 normal subjects of similar age. In obese hypertensive subjects, the IBW/IFV ratio was significantly increased (p less than 0.01) in comparison with both control subjects and nonobese hypertensive patients. After body weight reduction, blood pressure (p less than 0.01), heart rate (p less than 0.05), and the IBW/IFV ratio (p less than 0.01) significantly decreased. The decrease in the ratio was due to an absolute increase in the interstitial fluid volume, related to a shift of fluid volume from the intracellular to the interstitial space. Thus, obese hypertensive patients have an increased water cell content, causing an altered partition between the intracellular and the interstitial spaces.

Adult↗
PubMed1981

[Drepanocytosis and diffuse interstitial pulmonary fibrosis (author's transl)].

Respiratory disorders in homozygous drepanocytosis and double SC heterozygosis are mainly dependent on two factors : repeated infections with, more particularly, pneumococcus or mycoplasma, and epidoses of occlusion of the pulmonary circulation. Mutual reinforcement of these two factors occurs, in so far as the relative hypoxia of an infected lung increases the risk of falciform and thrombosis formation in the pulmonary arterioles. The particular physical and chemical properties of the drepanocyte red cell, and the anaemia, themselves lead to parallel disturbances in pulmonary circulation function and gas exchanges. Possible development of respiratory insufficiency is generally, therefore, the result of chronic pulmonary arterial hypertension. However, the results of respiratory function tests are often fairly analogous to those observed in moderate interstitial fibrosis : reduction in vital capacity, alveolo-capillary block, reduction in CO diffusion space, a shunt effect, and diminished pulmonary compliance. This problem is discussed in relation to findings of diffuse interstitial fibrosis in a 34-year-old man with double SC heterozygosis, who had numerous episodes of bone, abdominal, and pulmonary microinfarcts. The presence of a diffuse interstitial pulmonary fibrosis, evoked by radiological criteria and respiratory function tests and confirmed by transbronchial biopsy, no other aetiology being established, raises the question of the possible genesis of the fibrosis from repeated episodes of microvascular occlusion. Many factors may therefore be involved in the formation of fibrosis of this type, not only the pulmonary artery obstruction from the microthrombi but also the macrophagic perivascular inflammatory response related to the presence of foci of infarction and precipitation of pathological intravascular material.

Adult↗