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Biomedical subjects

H Simon

Publications and source records attributed to H Simon.

At least 325 records · Page 18Linked to original sources
PubMed1977

[Abnormal myocardial blood flow pattern after non-transmural infarction (author's transl)].

While coronary angiography was within normal limits in three patients with recurrent severe attacks of angina and non-transmural postero-lateral wall myocardial infarction, myocardial perfusion scintigraphy demonstrated an abnormal distribution pattern. In addition to recanalised thrombosis, embolism or spasm, abnormalities in the microcirculation are possible causes of the discrepancy between the coronary arteriogram and the scintigram. Myocardial perfusion scintigraphy is of particular diagnostic significance in this group of patients with coronary heart disease but normal coronary angiography. Treatment in the presence of this finding consists of administration of platelet-aggregation inhibitors.

Adult↗
PubMed1977

[Compromized myocardial perfusion in arrhythmias (author's transl)].

In 7 patients with arrhythmias of various origin the myocardial scintigram displayed either a diffuse or circumscript defect of the perfusion. The coronary arteriogram was normal in all patients. The localized defect of the perfusion in 2 patients was in the region of the upper part of the interventricular septum. Both had a left bundle brunch block. A correlation between the perfusion defect and the electrophysiological abnormality seems probable. The perfusion defect in one of the patients is most probably caused by a previous myocarditis followed by fibrous changes. In the other 6 patients the cause for the perfusion defect is not obvious. A history of myocarditis is missing. The presence of "small vessel disease" in those patients has however to be considered. Our results point to the relation between an abnormality of the microcirculation and arrhythmias in younger patients.

Adult↗
PubMed1977

Behavioral effects of lesions in the A10 dopaminergic area of the rat.

Experiments have been carried out with 150 rats in order to study some psychophysiological functions of the mesencephalocortico limbic dopaminergic A10 group. Lesions in the A10 area were made by using 6-hydroxydopamine (6-OHDA) local injections; 2 small volumes of injections were used at the same concentration (2 mug/1 mul or 1 mug/0.5 mul). In a first experiment the effects of these two injections were tested on locomotor activity measured in a circular corridor, 10 and 30 days after surgery. Injections provoked hyperactivity, mainly during nocturnal basal activity periods, but not during initial exploratory activity periods. The larger the injection, the more important the hyperactivity was. The larger injections induced important food spillage evidence through the wire floor of the home cage and perturbation in a passive avoidance learning. There was no change in body weight or in amount of ingested food. In a second experiment, the effects of local injection of 6-OHDA in the other CA structures or bundles situated in or near the ventral tegmental area were tested. Injections in the substantia nigra compacta, in the noradrenergic ventral bundle, in the dorsal periventricular system-tegmental radiations did not provoke locomotor hyperactivity. In a third experiment, a possible role of the median raphe (MR) nucleus in the A10-lesion induced hyperactivity was tested: first, radiofrequency MR lesions were made and no durable significant hyperactivity was recorded; secondly, 6-OHDA (1 mug/0.5 mul) was injected into the A10 area and activity was measured 10 days later: these injections provoked significant hyperactivity during the nocturnal basal and the diurnal basal activity periods. It might be concluded that neither the neighboring CA fibers nor the MR were directly involved in the ventral tegmental -- 6-OHDA lesions syndrome. Anatomical controls by using the Fink-Heimer silver impregnating method have demonstrated, first, that the 6-OHDA injections did not destroy fibers other than catecholaminergic and secondly, that the degenerations are found in the forebrain and cortical limbic A10 projections. Hypotheses are made about a possible general inhibitory role of the A10 in behavior, in the sence of selective and attentive arousal processes, often impaired in some mental illnesses.

Animals↗
PubMed1977

[Successful treatment of a supraventricular re-entry tachycardia in a patient with WPW and sick-sinus syndrome with permanent rapid atrial and QRS-inhibited ventricular pacemaker stimulation (author's transl)].

A supraventricular re-entry tachycardia was successfully treated in a patient with WPW and sick-sinus syndrome by permanent rapid atrial pacing and ventricular demand pacing. The use of a demand pacemaker with bipolar electrode avoided slow ventricular rates resulting from second degree A-V block during rapid atrial pacing. The trigger system of this pacemaker was not disturbed by unipolar atrial stimulation. Ventricular rates responded satisfactorily to physical and to emotional stress as a result of improved A-V conduction in these circumstances. Rapid atrial pacing has prevented the re-entry tachycardia. In an emergency the atrial pacemaker can be inhibited by a magnet, but otherwise discharges permanently at a constant rapid rate.

Electrocardiography↗
PubMed1977

Biplane translumbar aortography for evaluation of peripheral vascular disease.

Complete evaluation of the aortoiliac femoropopliteal system is necessary for the proper evaluation of lower extremity peripheal vascular ischemic disease. We have used a modified infrarenal translumbar approach since it is both safely and rapidly performed. An analysis of 212 consecutive cases (the last 182 with translumbar technic) revealed that 72 per cent of patients had significant atherosclerotic involvement of the aorta or one or more common or external iliac arteries, 43 per cent had significant bilateral involvement, and it was judged that retrograde femoral catheterization would have been difficult or impossible in 38 per cent. Biplane aortoiliac evaluation was added in our last seventy-nine studies. This provided additional diagnostic help in thirty-six of these cases and revealed an abnormality not otherwise visible in six of these patients. There were no serious complications in this series.

Aorta, Abdominal↗
PubMed1977

The thoracic outlet syndrome as a cause of aneurysm formation, thrombosis, and embolization.

The thoracic outlet syndrome may have a serious vascular component consisting of subclavian artery aneurysm with possible thrombosis and embolization which can result in severe ischemic symptoms in the upper extremity, gangrene, amputation, and even hemiplegia. Four cases of subclavian artery aneurysm in association with thoracic outlet syndrome are presented. Two of the patients required surgical intervention because of thrombosis and embolization, while the other two had prophylactic surgical procedure to prevent those complications.

Adolescent↗
PubMed1977

Synthesis of stereospecifically deuterated phenylalamines and determination of their configuration.

1. Starting from trans-cinnamic acid a chiral (-)3-phenyl-[2,3-2H]propionic acid has been synthesized using Clostridium kiuyveri cells as catalyst. 2. The chiral dideuterated acid has been converted by chemical methods to a mixture of (2R) and (2S)-phenyl[2,3-2H]-alanine. 3. By means of 1H nuclear magnetic resonance spectroscopy and the action of D and L-amino acid oxidase the configuration of the phenylalamine has been shown to be (2R, 3S) and (2S, 3S), respectively. The labelled phenylalanine is thus sterically and isotopically homogenous at position 3 but heterogenous at position 2.

Amino Acid Oxidoreductases↗
PubMed1977

The Erysichthon syndrome. Progression of coronary atherosclerosis and dietary hyperlipidemia.

One hundred nineteen patients with coronary artery disease confirmed by coronary arteriograms were studied. Cine coronary arteriography confirmed progression of atherosclerosis in 106 (89%) patients (mean age 50.9 yr) and nonprogression in 13 (11%) patients (mean age 50.3 yr). Progression was defined as follows: any increase to 50% stenosis, 50% to 75% narrowing, 75% to 90%, 90% to 99%, 99% to total occlusion. Only one patient of the 106 who progressed (less than 1%) had ideal values for both cholesterol and triglyceride. Three of 13 patients (23%) who did not progress had ideal lipid values (P less than 0.005). Fifty four of 106 patients who progressed had cholesterol levels greater than or equal to 250 mg%; none of 13 patients who did not progress had such levels (P less than 0.005). Thirty-nine of 98 (40%) patients who progressed had hypertension; only one (8%) who did not progress had hypertension (P less than 0.025). Seventy-four of 96 patients who progressed were smokers (77%); two of 13 nonprogression patients smoked (15%) (P less than 0.005).

Adult↗
PubMed1977

Preparation of (S)2-methylsuccinate and (2S,3S) [2,3-2H]2-methylsuccinate by biohydrogenation of 2-methylfumarate.

2-Methylfumarate can be hydrogenated by resting cells of Proteus mirabilis under an atmosphere of hydrogen gas. Optically pure (S)2-methylsuccinate is formed in a yield greater than 95%. The hydrogen addition, presumably catalyzed by the fumarate reductase, occurs in a trans fashion, as with succinate dehydrogenase of mammalian systems. Only one reactive enzyme-substrate complex with 2-methylfumarate seems to be possible.

Fumarates↗
PubMed1977

Small doses of apomorphine and chronic administration of d-amphetamine reduce locomotor hyperactivity produced by radiofrequency lesions of dopaminergic A10 neurons area.

The lesion of the ventral mesencephalic tegmentum region (VMT) induces a behavioral syndrome characterized mainly by locomotor hyperactivity and reduction of attention processes. Previous data indicated that this syndrome was due at least in part to the destruction of dopaminergic (DA) A10 neurons. In order to test this hypothesis, we examined the effects of two dopaminomimetics drugs: apomorphine (APO) and d-amphetamine (d-AMPH) on the VMT behavioral syndrome. The acute administration of very low doses of APO (30 microgram/KG; Sc) reduces the behavioral deficits; similarly a chronic administration of d-aMPH (two injections daily for 43 days) reduces locomotor hyperactivity. In these two cases, the lesioned rats activity reaches the control level. These results confirm the primary role of DA-A10 neurons in the VMT behavioral syndrome. Acute APO and chronic d-AMPH effects are discussed in terms of (i) reactivation of DA postsynaptic receptors disafferented after DA-A10 group destruction and (ii) strengthening of the hyperfunctioning of the remaining DA-A10 neurons. VMT-A10 syndrome could be a good animal model for pathophysiological studies.

Animals↗