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Biomedical subjects

R Clement

Publications and source records attributed to R Clement.

At least 19 recordsLinked to original sources
PubMed1990

[Doppler evaluation of blood flow of the lower limb].

UNLABELLED: Regional blood flow measurement in the limbs (BFLL) is of special interest in order to evaluate the consequences of hypertension. The purpose of this study is to assess the interest of the Doppler ultrasound method in the BFLL measurement among normotensive or borderline hypertensives young male adults. BFLL reproducibility was evaluated among 23 healthy subjects aged 21 +/- 2 y, height 177 +/- 8 cm, weight 75 +/- 13 kg at day one (D1) and three day later (D3). Measurements were made basically after 20 minutes lying at rest and after cold pressor test (CPT). BFLL estimation depends on common femoral artery diameter (FAD) echographic measurement at the thigh root and on velocity time interval (VTI) calculation with pulsed wave doppler using controlled incident angle and sample volume. The following parameters were measured: mean arterial pressure (MAP) using Dinamap, heart rate (HR), FAD, common femoral artery cross sectorial area (A), VTI and peripheral arteriolar resistances (PAR). Basic and CPT results at D1 and D3 were compared using paired "t" test. RESULTS: [table: see text] Comparisons between basic state and CPT demonstrate a significant decrease of VTI and BFLL, a significant increase of PAR. D remained unchanged. Doppler ultrasound method is easy to use. Systolic femoral volume measurement is relatively insensitive to small transducer positioning variations so that the method reproducibility is satisfactory.

Adult↗
PubMed1989

Early arterial modifications in young patients with borderline hypertension.

Pulse wave velocity, used as an indicator of arterial distensibility, was recorded in 123 young male subjects, 63 untreated patients with borderline hypertension and 60 control subjects. The measurement was made with a continuous Doppler unit coupled to an ECG. In both groups mean age was similar, but mean arterial pressure was increased in borderline hypertensive compared with control patients. In comparison with controls, borderline hypertensives showed an increased pulse wave velocity. A significant correlation was observed between mean arterial pressure and pulse wave velocity in both populations, but the two regression lines were significantly different (covariance analysis). This result suggests that pulse wave velocity modifications in borderline hypertensives are not solely due to the elevated pressure, but also reflect structural or functional changes in the arterial tree.

Adolescent↗
PubMed1989

Increased vasodilator response during stimulation of cardiopulmonary baroreceptors in borderline hypertensives.

1. The effects of passive leg elevation on the forearm circulation were compared in 14 borderline hypertensive and 16 normotensive men. 2. In the supine position, mean arterial pressure (MAP), heart rate (HR) and forearm blood flow (FBF) were significantly greater in borderline hypertensives. 3. With leg raising, MAP and HR did not change significantly from basal values. FBF increased by +0.6 +/- 0.2 (s.e.m.) mL/min/100 mL (P less than 0.02) in normotensives and by + 1.3 +/- 0.2 mL/min/100 mL (P less than 0.001) in hypertensives (P for difference between groups less than 0.05).

Adolescent↗
PubMed1989

[Increased vasodilation response to the stimulation of low pressure mechanoreceptors in borderline hypertension].

Passive lifting of the lower limbs (antitilt) is a simple manoeuvre which stimulates low-pressure mechanoreceptors. Patients with borderline hypertension have an alteration of the arterial baroreflex modulated by an increased inhibitory effect of cardiopulmonary mechanoreceptors on vasomotor centres. The repercussions of antitilt on mean arterial pressure (MAP), heart rate (HR) and blood flow rate in the forearm (FRFA) were studied in 30 male subjects aged 18 to 25 years: 14 with untreated borderline hypertension ("patients") and 16 controls. FRFA was measured with a plethysmograph by means of a mercury constraint gauge. MAP was recorded during exploration with a DINAMAP instrument. The parameters were measured in recumbent position, then within minutes of the antitilt manoeuvre. In recumbent position the differences between patients and controls were: MAP 94.7 +/- 6 vs 84.7 +/- 7 mmHg (p less than 0.001); HR 76 +/- 13 vs 63 +/- 9 beats/min (p less than 0.01); FRFA 4.6 +/- 1.5 vs 3.5 +/- 1.4 ml/min/100 ml (p less than 0.05). Following antitilt, MAP and HR remained unchanged in the two groups, but there was a significant increase of FRFA in both controls (+ 0.6 +/- 0.2 ml/min/100 ml; p less than 0.02) and patients (+ 1.3 +/- 0.2 ml/min/100 ml; p less than 0.001). This increase was significantly greater in patients than in controls (p less than 0.05). This study shows that antitilt produces an increase of blood flow rate in the forearm that is more pronounced in patients with borderline hypertension than in controls. The stability of MAP and HR is in favour of non-actuation of the high-pressure arterial baroreflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Improvement of myocardial function by trifluoperazine, a calmodulin antagonist, after acute coronary artery occlusion and coronary revascularization.

Activation of an intracellular calcium-calmodulin complex may play an important role in myocardial injury induced by ischemia and reperfusion. Trifluoperazine, a calmodulin antagonist, was used before ischemia to enhance myocardial preservation by preventing intracellular calcium accumulation. The experimental model used an isolated in situ pig heart (19 control animals and 15 trifluoperazine-treated animals) subjected to occlusion of the left anterior descending coronary artery for 60 minutes followed by 60 minutes of hypothermic potassium crystalloid cardioplegic arrest and 60 minutes of reperfusion. Myocardial segmental function measured by ultrasonic crystals showed that active systolic segment shortening was abolished in the distribution of the left anterior descending artery after 60 minutes of occlusion irrespective of the treatment, whereas that not in the distribution of the left anterior descending artery increased by about 15% in both groups of animals. Restoration of systolic segment shortening in the distribution of the left anterior descending artery 60 minutes after reperfusion was 12% and 42% of baseline levels in untreated and trifluoperazine-treated animals, respectively (p less than 0.01). This improvement in segmental function by trifluoperazine was reflected in significantly (p less than 0.05) better global myocardial contractility and compliance and in significantly (p less than 0.01) greater total coronary blood flow and myocardial oxygen consumption. Trifluoperazine also increased myocardial creatine phosphate content in the distribution of the left anterior descending artery (p less than 0.01) during reperfusion, and creatine kinase release was reduced (p less than 0.05). Our results suggest that trifluoperazine improved regional myocardial function after acute occlusion of the left anterior descending artery and reperfusion and that global cardiac performance was thereby improved. The beneficial effects of trifluoperazine may be exerted by prevention of myocardial injury associated with the calcium-calmodulin complex in ischemic and reperfused myocardium.

Adenosine Triphosphate↗
PubMed1988

Perioperative morbidity in diabetics requiring coronary artery bypass surgery.

We retrospectively evaluated the operative results in 384 patients with diabetes mellitus operated on for ischemic coronary artery disease over a six-year period compared with a random group of 396 patients selected from 2,069 nondiabetic patients who underwent operation during the same study period. In our analysis of 13 preoperative and 5 intraoperative variables, diabetics revealed a significantly increased incidence of hypertension (p less than 0.05) and a smaller proportion of men (p less than 0.05). All other variables were not significantly different. The incidence of perioperative myocardial infarction, renal failure, neurological sequelae, leg infections, or thromboembolic events was similar in diabetic and nondiabetic patients. Hospital stay, however, was significantly increased in the diabetic group (p less than 0.05). The diabetic patients requiring intraaortic balloon counterpulsation had a significantly higher incidence of all postoperative complications analyzed compared with diabetics without balloon support (p less than 0.01), whereas the nondiabetic subset requiring intraaortic balloon counterpulsation exhibited only a significantly higher incidence of renal failure (p less than 0.01) and neurological complications (p less than 0.05). These results indicate that diabetes per se does not significantly increase morbidity in coronary bypass surgery.

Coronary Artery Bypass↗
PubMed1988

Improved myocardial performance induced by clofibrate during reperfusion after acute myocardial infarction.

The increase of cellular fatty acids appears to be one of the causes of the myocardial injury during ischemia and reperfusion. This study was designed to examine whether a hypolipidemic drug such as clofibrate can reduce the myocardial injury during ischemia and reperfusion. Clofibrate was fed to experimental pigs for 9 days. Isolated in situ hearts from both experimental and control pigs were subjected to 60 min of regional ischemia induced by occluding the left anterior descending coronary artery, followed by 60 min of global ischemia by hypothermic cardioplegic arrest and 60 min of reperfusion. The clofibrate feeding resulted in the better cardiac performance as judged by increased coronary blood flow, improved left ventricular function, and reduced myocardial injury as judged by creatine kinase release. Although the clofibrate-fed animals contained higher levels of thiobarbituric reactive materials, the free fatty acid levels of plasma and myocardium were much lower compared with control animals. The clofibrate feeding was also associated with increased peroxisomal catalase and beta-oxidation of fatty acids. These results suggest that decreased levels of free fatty acids in the plasma and the myocardium and increased catalase activity induced by antilipolytic therapy appear to provide beneficial effects to the myocardium during ischemia and reperfusion.

Animals↗
PubMed1988

[Plasma viscosity and erythrocyte filterability in borderline hypertension].

Hemorheological constants (plasma viscosimetry and erythrocyte filtrability index) were studied in 153 male subjects aged 19 to 23. Borderline hypertension defined by clinical criteria was found in 61 of these patients. Whilst there was no notable modification in plasma viscosity, by contrast there was a significant link between erythrometry and systolic and diastolic blood pressure. Erythrocyte deformability was all the more marked as blood pressure rose. These results would contrast with findings in the literature in cases of definite hypertension. The borderline nature of hypertension and the youth of the population was such that it could be considered that barometric factors had not yet influenced erythrocyte filtrability. The following hypothesis is therefore attractive: initially the red cell adapts itself to any possible increase in peripheral resistance. As the years go by its deformability is lessened by adverse changes affecting its membrane cytoskeleton.

Age Factors↗
PubMed1988

Effect of ischemia and reperfusion of the myocardium on in vitro beta-oxidation of fatty acids.

The in vivo oxidation of perfused [14C]-labeled fatty acids has been shown to decrease dramatically in hypoxic hearts. This study addresses the influence of ischemia and reperfusion on the enzymic activities of beta-oxidation of fatty acids in mitochondria and of peroxisomal origin. The rate of beta-oxidation of fatty acids in the isolated mitochondria from myocardium of swine fed control diet declined about 20% by the ischemic insult induced by hypothermic cardioplegic arrest. Upon reperfusion, the rate of mitochondrial beta-oxidation returned to a normal level. In clofibrate-fed animals, the rate of mitochondrial beta-oxidation did not vary significantly between control, ischemic, and perfused tissues. Furthermore, neither in control nor in clofibrate-fed animals did the rates of peroxisomal beta-oxidation of fatty acids vary significantly in the ischemic or reperfused tissues as compared to that of preischemic controls. These results suggest that ischemia does not contribute to any loss of enzymic activity in beta-oxidation of fatty acid cycles either in mitochondria or peroxisomes. Furthermore, the feeding of 0.5% (w/w) clofibrate to pigs increased the rate of mitochondrial beta-oxidation of fatty acids only by 50% while that of peroxisomes increased threefold. A similar threefold increase in catalase activity was also produced by clofibrate feeding. These results suggest that the heart plays a role in the hypolipidemic action of clofibrate.

Animals↗
PubMed1987

Role of xanthine oxidase inhibitor as free radical scavenger: a novel mechanism of action of allopurinol and oxypurinol in myocardial salvage.

Xanthine oxidase (XO) has been hypothesized to be a potential source of oxygen-derived free radicals during reperfusion of ischemic myocardium based on the fact that allopurinol, a XO-inhibitor, can reduce reperfusion injury. In this communication we report that both allopurinol and oxypurinol, the principle metabolite of allopurinol, prevent the reperfusion injury in isolated pig heart. However, we found that neither pig heart nor pig blood contain any XO activity. Our study showed a direct free radical scavenging action of these XO-inhibitors during ischemia and reperfusion, as judged by the reduction of free radical signals when compared using an Electron Paramagnetic Resonance Spectrometer. Using a Luminometer, we also confirmed that both allopurinol and oxypurinol can scavenge ClO2, HOCl, and significantly inhibit free radical signals generated by activated neutrophils. These XO-inhibitors, however, failed to scavenge O2. and OH. radicals. Our results suggest that these XO-inhibitors salvaged the ischemic-reperfused myocardium by scavenging free radicals, and not by inhibiting XO in the pig heart.

Adenosine Triphosphate↗
PubMed1987

[Nycthemeral blood pressure monitoring in the diagnosis of borderline arterial hypertension in young adults].

PURPOSE: Evaluating Blood Pressure Monitoring contribution at rest to the diagnosis and pathophysiology of borderline (BL) hypertension in the twenties. METHOD: a nycthemeral blood pressure recording each 15 minute has been performed during the 48 first hours of hospitalisation on two groups of white twenties males with a Dinamap: 143 CONTROLS. Mean age: 21.1 +/- 2 yrs, mean height: 177 +/- 7 cm, mean weight: 71 +/- 11 kg; 104 BL hypertensive patients. Mean age: 21 +/- 2 yrs, mean height: 178 +/- 7 cm, mean weight: 78 +/- 12 kg. Mean BP recording levels are smaller than casual measurements in two groups: CONTROLS (Casual BP: 125/71, BP recording on 24 hours: 117/60, day time: 121/63, nighttime: 110/54 mmHg). BL hypertensives (Casual BP: 144/83, BP recording on 24 h: 132/69, daytime: 137/73, nighttime: 121/60 mmHg). Nycthemeral BP variability measured by the standard deviation of mean pressure is not different in two groups for systolic variability, it significantly differs for diastolic variability (BL: 7.6/CONTROLS: 5.5, p less than 0.01). Correlations between casual BP and diurnal records are stronger in controls than in BL patients showing a lower predictive value of clinical assessment in BL patients. Though the same heart rate at sleep, BP is significantly higher in BL than in controls. It probably means that factors different from sympathetic activity are involved in pathophysiology of borderline hypertension. The whole measurement study on 24 hours of two groups show an important overlap (the 65th percentile in BL systolic BP correspond with the 95th of controls, the 74th percentile in BL diastolic BP correspond with the 95th in controls). That make difficult the recording evaluation for a given patient.

Adult↗
PubMed1986

Operative and nonoperative treatment of mallet finger.

Forty-four patients with 47 mallet fingers were reviewed to compare the results of operative (24 fingers) and nonoperative (23 fingers) treatment. Distal interphalangeal (DIP) joint extension, DIP flexion, total active motion of the DIP joint, proximal interphalangeal (PIP) extension, PIP flexion, total active motion of the PIP joint, cold intolerance, and persistent pain after treatment were not significantly different in patients treated by surgery or splinting. Secondarily, we compared fingers with and without a fracture of the distal phalanx, and the variables mentioned above were also unaffected by the presence or absence of fractures of the distal phalanx. About one-third of all patients had decreased PIP joint motion following treatment. In about 16% of all patients this loss of PIP motion was more important in determining finger function than DIP motion or symptoms related to the DIP joint. We recommend careful examination of the PIP joint and repeated monitoring of the joint motion. If the PIP joint becomes stiff, therapy and splinting should be used to minimize permanent stiffness. We believe a prospective randomized comparison of operative and nonoperative treatment of mallet finger should be conducted. Such a study would help determine the ideal treatment for mallet finger.

Exercise Therapy↗
PubMed1982

[Exercise-induced malignant hyperthermia in a patient with familial ichthyosis vulgaris. Muscular carnitine deficiency as contributing factor (author's transl)].

A young soldier with familial ichthyosis vulgaris developed malignant hyperthermia after an intensive exercise. Ichythyosis was considered as a predisposing factor, but the finding of a low muscular carnitine level raises the problem of a relationship between exercised-induced malignant hyperthermia and lipid metabolism disorders.

Adult↗
PubMed1979

[Experimental study of vibrio parahaemolyticus (biotype 2) transfer from water and sediments to benthic marine food chain organisms].

Transfer of Vibrio parahaemolyticus (biotype 2) from sediments to water and from water to benthic marine organisms was studied experimentally using a streptomycin-resistant strain. Transmission by trophic pathways was also studied using reconstituted marine food chains (Mytilus edulis, Nereis diversicolor, Carcinus maenas, Scorpaena porcus, Mus musculus). Water colonization by sediments could be observed only at temperatures above 16 degrees C. Sediments could well constitute a disseminating reservoir for these germs, their cycle in water being dependent of the cycle followed in the sediments. Contamination of animal organisms is essentially effected by a direct mean, either water or sediments; transfer by trophic pathways being negligible. Infection of land consumers (mice) is linked quantitatively to the nature of the last marine organism of the food chain since bacteria can flourish in the digestive tract of certain animals (Carcinus maenas).

Animals↗