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Biomedical subjects

M Verhas

Publications and source records attributed to M Verhas.

At least 19 recordsLinked to original sources
PubMed1992

Bone blood flow and in vitro proliferation of bone marrow and trabecular bone osteoblast-like cells in ovariectomized rats.

Ovariectomy in the rat induces a rapid osteopenia associated with an elevated bone turnover. One hundred and twenty-day-old rats were ovariectomized (OVX) or sham-operated (n = 6-8 per group and per time period studied). 45Ca accretion rate and bone blood flow (microspheres trapping technique) in the femurs were determined at 28, 42, 84, and 119 days after ovariectomy. Both parameters were markedly increased by 84 days and subsided thereafter. At the 42nd day, when bone turnover was maximal, bone marrow and trabecular bone cultures were obtained from sham-operated and ovariectomized animals (n = 10/group). Proliferation rate of bone marrow cells and trabecular osteoblast-like cells estimated by fibroblast colony-forming units (FCFU) efficiency and cell counting was markedly increased in primary and secondary cultures in ovariectomy. These data fitted well with the enhanced number of osteoblasts observed in situ in the long bone metaphyses of estrogen-depleted animals. As estrogens were shown in the literature to inhibit proliferation of the red cell line and of other hemopoietic lines, it is possible that estrogens, through a general mechanism, inhibit hemopoietic and stromal lines and also the proliferation of bone marrow-derived trabecular bone cells.

Animals↗
PubMed1992

Use of a urea breath test versus invasive methods to determine the prevalence of Helicobacter pylori in Zaire.

The prevalence of Helicobacter pylori infection in Zaire was determined by means of a [14C] urea breath test in 133 asymptomatic subjects, by culture and histological examination of biopsies in 324 consecutive endoscopy patients with chronic epigastric complaints, and by both the breath test and culture/histology in a subset of 92 patients. Sixty healthy Belgian students or hospital laboratory workers were also included for comparison. The prevalence of Helicobacter pylori was significantly higher in asymptomatic Zairian subjects (77.4%) than in the Belgians (30%; p less than 10(-6)). Infection was also acquired much earlier in life in Africans, 66% of the children aged 5 to 9 years already being infected versus none of the Belgian subjects below the age of 20 years. In Zaire, however, the prevalence of Helicobacter pylori in patients with gastroduodenal disorders (87.5%) was similar to that in the group of asymptomatic subjects (77.5%) after adjustment for age and other epidemiological parameters (gender, place of residency, education level, smoking and drinking habits) in a multivariate analysis. The high rate of acquisition of Helicobacter pylori infection in Zaire emphasizes the need to consider the baseline prevalence of Helicobacter pylori in a defined population when studying its association with various diseases.

Adult↗
PubMed1991

Remote cortical dysfunction in aphasic stroke patients.

We studied the effect of deep-seated left hemispheric lesions on cortical blood flow in 18 right-handed aphasic stroke patients. Regional cerebral blood flow was measured at rest and during the performance of a functional naming test using the two-dimensional xenon-133 inhalation method. Compared with 10 controls, at rest the patients showed regional cortical hypoperfusion in the left frontoparietal region. In the controls, activation patterns from the rest to the test condition involved mainly the left hemisphere areas. In the patients, a lack of blood flow change was observed in several areas that were usually hypoperfused at rest. However, in patients with slight verbal expression disorders there were obvious blood flow increases in other brain regions in both hemispheres. Such cortical functional reorganization and the presence of a remote cortical dysfunction could play a role in the pathophysiology of language disorders.

Aged↗
PubMed1990

[Indications for scintigraphy with gallium 67 and with indium 111 labelled leukocytes in the diagnosis of postoperative infections in osteo-articular surgery].

A prospective scintigraphic study using Gallium 67 and granulocytes labelled with Indium 111 was carried out in 60 patients who were thought to have infection following orthopaedic operations. Both investigations gave positive results in 11 of the 16 infections observed. The Indium 111 labelled leucocyte scan was more accurate than the Gallium 67 studies in delineating patients who did not have an infection, and appears to be more reliable in the diagnosis of post-operative sepsis.

Adolescent↗
PubMed1990

Effects and interactions of 17 beta-estradiol, T3 and 1,25(OH)2D3 on cultured osteoblasts from mature rats.

Osteoporosis being frequently associated with hyperthyroidism and, mostly after menopause, with deficiency in estrogens, we tried to elucidate the interactions of estrogens and triiodothyronine (T3) with calcitriol by using cultured osteoblast-like cells obtained from mature rat bone. The tested parameters included [3H]thymidine incorporation, evaluation of the alkaline phosphatase activity of the cell layer and osteocalcin production in the culture medium. At physiological concentrations, 17 beta-estradiol and T3 stimulated alkaline phosphatase activity, did not enhance osteocalcin production and slightly inhibited [3H]thymidine incorporation. At higher concentrations, 17 beta-estradiol decreased the alkaline phosphatase and osteocalcin response to calcitriol whereas T3, although decreasing alkaline phosphatase activity, markedly increased the osteocalcin secretion elicited by calcitriol. These observations emphasize the complex physiology of osteoblasts and confirm different behaviors of alkaline phosphatase and of osteocalcin as markers of bone turnover.

Alkaline Phosphatase↗
PubMed1990

Anaemia and marrow blood flow in the rat.

An increase in bone marrow blood flow has been previously described in anaemic rabbits and dogs. We examined the effect of haemorrhage and haemolysis in female Sprague-Dawley rats, with the hypothesis that high blood flow was related to hyperplasia of bone marrow tissue and that the increase would affect bone as well. Blood flow was measured in tibia and femur by the microspheres trapping method. Chronic anaemia was accompanied at day 32 by a marked increase (factor of 1.7-1.9) in blood flow to bone marrow and to bone. On the other hand, no increase in blood flow was observed in chronic compensated anaemia, showing that anaemia per se and not stimulation of erythropoiesis was responsible for the increase. We then explored the effect on blood flow of two factors associated with anaemia. Erythropoietin 4 U/d for 4 d failed to induce any increase in bone and marrow blood flow. Systemic hypoxia (76 mmHg for 3 d) reduced the fraction of cardiac output conveyed to bone and marrow by 40-50%, but this decrease was more than compensated by an increase in cardiac output. We conclude that neither erythropoietin nor low tissue pO2 is the direct cause for the increase in bone and marrow blood flow observed in anaemia.

Anemia↗
PubMed1990

Pathogenesis of aphasia in deep-seated lesions: likely role of cortical diaschisis.

In order to study the pathophysiology of language disorders due to deep-seated left-hemisphere lesions not involving the cortex, a population of 43 right-handed stroke patients (29 aphasic) presenting with such lesions was studied clinically and by regional cerebral blood flow measurements (two-dimensional xenon-133 inhalation method). Most of the patients were studied sequentially between the 1st and 3rd months after stroke. Cortical diaschisis did not account for the whole clinical picture: the remote effect on the cortex could explain the occurrence of aphasia and its severity but not the type of aphasia. Furthermore, the clinical improvement observed in most cases was not accompanied by the disappearance of the diaschisis.

Adult↗
PubMed1990

Remote effect of deep-seated vascular brain lesions on cerebral blood flow.

We measured regional cerebral blood flow using the xenon-133 inhalation method, at approximately 1 month after onset, in 60 stroke patients who had no evidence of major carotid artery stenosis or occlusion. Their single lesions (43 infarcts and 17 hematomas) were located in the capsulothalamolenticular region, sparing the cortex. Hemispheric mean cerebral blood flow was reduced on the side of the lesion in 25 patients and on both sides in 20. Regional hypoperfusion was observed in 46 patients (ipsilaterally in 34, bilaterally in 10, and contralaterally in two). Regional hypoperfusion was observed most frequently in the frontal lobe, particularly in the motor and premotor cortices of the prerolandic area. The 46 patients with regional hypoperfusion were compared with the 14 patients without regional hypoperfusion, considering the size and location of the lesion as well as the functional and analytic motor performances. As a rule, the lesion was slightly smaller and more posterior and the functional (p less than 0.001) and analytic (p less than 0.05) motor performances were significantly better in the 14 patients without regional hypoperfusion. Since the xenon-133 inhalation method examines cortical blood flow, we can attribute blood flow reductions resulting from deep-seated lesions to a functional depression akin to diaschisis. Interpretation of the clinical consequences and pathogenesis of this phenomenon requires further sequential and pathologic studies.

Administration, Inhalation↗
PubMed1989

[Left ventricular function in obstructive chronic bronchopneumopathy].

Left ventricular (LV) function was studied, using echocardiography, radionuclide angiography and right catheterization, in 20 patients (mean age 60.9 +/- 1.5 years) with severe stable chronic obstructive pulmonary disease (COPD) and without known heart disease. The diagnosis of LV failure, suspected on clinical grounds in 8 of these patients, was confirmed by raised pulmonary capillary wedge pressure (PCWP) in only one patient. Nineteen subjects had normal PCWP and LV ejection fraction (LVEF) values, radionuclide LVEF and end diastolic LV dimension being the most powerful discriminators between the single abnormal patient and the others. Echocardiograms of sufficient quality were obtained in 11 out of the 19 normal patients and constantly showed LV dimensions in the lowest part of the normal range. The stroke volume index (SVI) - cardiac output being measured by thermodilution - was found to be decreased in 9 of 14 patients with normal LVEF values. We conclude that in patients with severe COPD (1) LV failure is quite unfrequent and the empirical use of digitalis should not be recommended, (2) radionuclide angiography is the most useful procedure for routine evaluation of LV function and (3) a decreased SVI is frequently found in patients with a small LV cavity and a normal LVEF, suggesting some degree of diastolic dysfunction of the left ventricle.

Blood Volume Determination↗
PubMed1988

Bone loss and bone blood flow in paraplegic rats treated with calcitonin, diphosphonate, and indomethacin.

Sham-operated (SO) and paraplegic rats were treated from the day of operation during a period of 4 or 6 weeks with salmon calcitonin 4 IU/kg/day or a diphosphonate (APD) 1mM/kg/day or indomethacin 2.5 mg/kg/day. The consequence of spinal cord section on the femur and tibia is a loss of mineral which affects predominantly trabecular bone (-24 and -13% in calcium content for the tibial metaphysis and the whole bone, respectively, when compared with the SO controls), a twofold increase in bone blood flow as measured by the technique of the microspheres trapping, a moderate decrease of the 72 hour 45Ca accretion rate in the bone shaft, and an increase in the number of metaphyseal osteoclasts in the tibia. In paraplegics, all three drugs inhibit bone loss to some degree, calcitonin and indomethacin being mostly effective on the cortical bone of the shaft, and APD tremendously increasing the trabecular network of the metaphysis. APD is the only drug to exhibit a significant effect on the calcium content of the bones of the SO controls, but some effect is apparent for calcitonin on X-rays and histological preparations. The increase in bone blood flow in paraplegics is unaffected, this point being discussed in view of the hypothesis of the resorptive action of prostaglandins produced by newly formed vessels. 45Ca accretion rate increases in the shaft of calcitonin-treated paraplegics, whereas it decreases in APD-treated controls and paraplegics. The number of osteoclasts decreases in paraplegics treated with calcitonin and indomethacin, and increases in both controls and paraplegics treated with APD.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Predictors of the variation of the ejection fraction during exercise in patients with and without coronary heart disease.

The aim of this study was to determine the factors influencing the different response of the ejection fraction (EF) of the left ventricle at exercise observed in patients with and without significant coronary heart disease. We have studied 98 patients referred for coronary angiography (82 men, 16 women), of whom 49 patients had a previous myocardial infarction and 71 patients had significant coronary heart disease. Exercise testing was performed and combined with a cardiac blood pool imaging at equilibrium. The variation of the EF between rest and peak exercise (delta EF) was measured. Twelve clinical, exercise-related, isotopic, and coronary arteriographic variables were examined in a linear univariate and statistical analysis. In the univariate regression, seven variables were significant regressors on the delta EF. In the multivariate regression, only four variables were significant regressors on the delta EF. Three independent predictors were found: the rate-pressure product, the ST depression, and the occurrence of a previous myocardial infarction. These three independent predictors reflect the myocardial functional reserve.

Coronary Disease↗
PubMed1986

The effect of orchidectomy on bone metabolism in aging rats.

We have shown that orchidectomy in postpubertal 55-day-old rats led beyond 2 months to a decrease in bone growth and loss of weight. At 1 month postorchidectomy, we observed a three-fold increase in bone blood flow, an increase in calcium accretion rate, and an increase in the number of osteoclasts in the metaphysis. In the present experimental study, orchidectomy was performed in 1-year-old rats when bone growth in length was no longer measurable. In the tibia and femur we observed a decrease in bone volume, a still more rapid decrease of bone calcium during the first postoperative month, a thinning of the cortical width, an initial increase in calcium accretion rate (+20% when compared to 31 days controls) followed by a decrease at 120 days (-22% and -11% when compared to controls for tibia and femur respectively), a 29% increase in bone blood flow, and an increase in the number of osteoclasts. We conclude that androgen deprivation in young and old animals leads to a modified bone architecture, independent of the androgen impact on bone growth.

Animals↗
PubMed1985

Prognostic value of computed tomography in aphasic stroke patients.

In order to evaluate the prognostic value of CT scan in aphasic stroke patients, a prospective study was performed during the first 3 months of the disease. The severity of the language disorders was assessed by means of a quantitative method. In cortico-subcortical lesions, the verbal expression recovery rate and the final verbal expression and comprehension status depended on the infarct size. No relation was observed between the latter and the verbal comprehension recovery rate. In deep-seated lesions, computed tomography provided no information concerning the prognosis.

Aged↗
PubMed1979

Simple, fast preparation of gallium-68-labelled human serum albumin microspheres.

Following a study of the main factors involved in the 68-Ga labelling of human serum albumin microspheres (H.S.A.M.), especially methods of production and preparation of active solution and conditions of radioelement fixation on the protein support, the practical details of a fast technique (60 min) based on the process described by Hnatowich are presented. This method gives high labelling yields (93 +/- 3%), and after washing of the microspheres leads to a radiopharmaceutical product almost without free 68Ga (less than 2%). The spheres ready for use carry a total radioactivity corresponding to about 35%, including decay, of the activity originally recovered in the generator eluate and to more than 98% of that, found in the final suspension. The labelled product is sterile, non-pyrogenic and non-toxic. When it is injected in animals by left ventrical catheterization the uptake rates in the heart, lungs, spleen, left kidney and right kidney are similar to those observed with reference 85Sr-labelled carbonized microspheres. This radiopharmaceutical, easy to prepare and having excellent biological and nuclear properties, seems ideally suited for the scanning of organs by position emission tomoscintigraphy.

Animals↗
PubMed1979

Brain distribution and kinetics of 11C-chlorpromazine in schizophrenics: positron emission tomography studies.

The positron emitter 11C (20 minutes half-life) permits the labeling of chlorpromazine (CPZ) and the study of its distribution in humans by external counting. Trace amounts of 11C-CPZ were injected intravenously into 22 schizophrenic patients all untreated for several months with neuroleptics. The brain uptake was 6.04 +/- 1.6% of the injected dose 15 minutes after the injection, and it remained constant for 45 minutes. By positron emission tomography, the drug distribution was shown to be in the gray matter, and such structures as the cortex, caudate nucleus, thalamus and putamen could be identified. This new methodology will be helpful in studying specific receptors in humans in a noninvasive way.

Adolescent↗