Search PubMed⌕ Search

Biomedical subjects

M Verhas

Publications and source records attributed to M Verhas.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1979

Bone blood flow measured by 85 Sr microspheres and bone seeker clearances in the rat.

This paper investigates further the relationship between the initial bone clearance of a bone-seeking radioisotope or labeled substance and the bone blood flow. The bone blood flow of rats was modified over the widest possible range of physiological values by heating and cooling their hindlimbs. Osseous blood flow was measured by the arteriolar trapping of labeled microspheres of 15 micrometer diameter injected into the left ventricle. The plasma clearances of 45Ca and 99 m Tc by bone were measured 10 min after the intravenous injection of radiocalcium and of 99 m technetium pyrophosphate. The extraction ratio for 45Ca over the 10-min interval (45Ca clearance/bone plasma flow) was 0.60 for low blood flows, 0.40 for blood flows at rest, and 0.25 for high values of flow. The data for 99 m Tc were, respectively, 0.68, 0.34, and 0.22. Initial bone clearances of either substance should not be used to measure the increases in bone blood flow over the values at rest.

Animals↗
PubMed1976

Use of 99mTc-labeled albumin microspheres in cerebral vascular disease.

The intracarotid injection of radioalbumin microspheres (15 and 30 mum) is followed by scanning procedures that permit the description of the cerebral bloodflow distribution. The method is reproducible. Injection can be made into the internal and common carotid arteries, as well as into the aortic arch or the left ventricle. This last procedure makes it easy to examine patients with severe extracranial vascular stenosis or thrombosis and permits comparison of the two hemispheres. Most patients (88%) injected on the affected side showed one or more local vascular deficits. The method therefore is more efficient than pertechnetate scanning or arteriography.

Aged↗
PubMed1975

Study in cerebrovascular disease: brain scanning with technetium 99m pertechnetate; clinical correlations.

A prospective brain scanning study using technetium 99m pertechnetate was performed in 84 patients with cerebral infarction. No correlation was found between vascular angiographic findings and the frequency of positive scans. A comparison with clinical motor and mental evaluation showed a good correlation between abnormal scans (58 percent) and poor initial test resutls. A half-life of 17 days characterized the time course of positive scans according to their density and abnormal radioisotopic uptake area.

Activities of Daily Living↗
PubMedDate not supplied

Correlation between inhibition, working memory and delimited frontal area blood flow measure by 99mTc-Bicisate SPECT in alcohol-dependent patients.

Recently detoxified non-neurological alcoholic patients appear to be impaired in cognitive tasks measuring inhibitory processes as well as working memory (involving storage and manipulation of information). The aim of this study was to investigate in alcoholic participants the relationship between these two cognitive functions and regional cerebral blood flow (rCBF) studied at rest in regions of interest selected on the basis of recent PET studies which explored inhibitory and working memory in normal subjects. Twenty non-neurological alcoholic patients and 20 normal volunteers were selected for a neuropsychological exploration, including assessment of inhibition processes (by means of the Hayling test) and working memory (by means of the Alpha-span task). rCBF of alcoholics was also evaluated with a semi-quantitative method using a 99mTc-Bicisate single photon emission computed tomography (SPECT) procedure. Alcoholic patients performed worse than controls in the alphabetical condition of the Alpha-span task (involving manipulation and storage of information), and on the Hayling test. Significant correlation emerged between inhibition performance and both the bilateral inferior (left BA 47, r = -0.40; right BA 47, r = -0.599) and median frontal gyrus (left BA 10, r = -0.55; right BA 10, r = -0.59), but not with the region of reference (occipital/cerebellum, r = -0.13). Coordination of storage and manipulation was correlated with bilateral median frontal (left BA 10/46, r = -0.50; right BA 10/46, r = -0.45), but not with bilateral parietal area (left BA 7, r = -0.12, right BA 7, r = -0.18). These results suggest a relationship between inhibition and working memory deficits in alcoholic patients, and regional rCBF measured in frontal areas. Clinical implications of these data related to alcohol relapse are discussed.

Alcohol Drinking↗
PubMedDate not supplied

Lack of evolution of the cerebral blood flow during clinical recovery of a stroke.

Cerebral blood flow and clinical parameters were studied in 30 stroke patients at 15th, 30th, 60th, 90th days after the cerebral insult (Xenon 133 inhalation method). The clinical improvement was not accompanied by a progressive normalization of the CBF at rest. No relationship was found between the clinical data and the CBF values; either on the affected hemisphere or on the contralateral one. It is concluded that measurement of the CBF at rest has no predictive value as regards further clinical evolution.

Adult↗