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Biomedical subjects

M Nasseri

Publications and source records attributed to M Nasseri.

At least 37 records · Page 2Linked to original sources

Comparative studies on the effect of oxygen high pressure (OHP) on different species; with special reference to the organ preservation.

Different species of animals (warm-blooded, poikilotherms and cold-blooded) were exposed to oxygen high pressure (OHP) (1-4 ata) for 2-8 h. OHP revealed (a) a different vulnerability in various species; (b) an inverse correlation between basal oxygen consumption and their vulnerability; (c) the critical point of the toxic effect of OHP in normothermia was an exposition time of 2 h with 2 ata OHP; (d) morphological changes of lung, CNS and vessels -- intense folding of alveolar septa with cell hyperplasia and hypertrophy; (e) electron-microscopical demonstration of damaged endothelial cells with total or partial occlusion of the capillaries.

Animals↗

[Behavior of vasomotor tonus after lung autotransplantation].

In eight lung autotransplants and six normal lungs the vasomotor activity was tested with norepinephrine and acetylcholine. In autotransplants and normal lungs both substances elicit the same effects. The long-term interruption of the central innervation does not provoke a vasoconstriction in lung autotransplants.

Acetylcholine↗

[Pressures, blood gases, pH, lactate and pyruvate concentrations in the portal venous blood in patients after laparotomy during the first 9 days (author's transl)].

In 24 patients (16 women, 8 men, mean age 60 years), who underwent abdominal operations and who had a uncomplicated postoperative course, a teflon-tube was inserted into the portal vein at the end of laparotomy and remained there for maximal 9 days. The mean values of the portal venous pressure as well as of the portal-central venous pressure gradient are unchanged during the period of all 9 days and are between 7,4 and 7,9 mmHg, between 5,6 and 6,9 mmHg respectively. The arterio-portal venous 0(2)-content difference shows in the mean no fluctuations and is about 2 Vol.%. On the first postoperative day the lactic and pyruvic acid concentrations in the artery and portal vein are moderately, but significantly elevated and decrease to normal values until day 7. - 9.

Adult↗

[New methods of circulatory support: cardiac transplant as auxiliary pump (author's transl)].

A simple method of dystopic cardiac transplantation as a left-heart bypass was experimentally studied and details of the method are described. The hemodynamic investigation of this biological assisted circulation on the normal and failing heart, which was induced by subtotal occlusion of the asc. aorta, as well as its longtime support of the chronically damaged left myocardium showed the efficacy of this method. The advantages of this biological method in comparison to that of mechanical devices and orthotopic cardiac transplantation are discussed.

Angiography↗

[Dopamine effects on the pulmonary circulation of innervated and autotransplanted lungs (author's transl)].

The effects of dopamine on the pulmonary vascular resistance were investigated in 7 normal and 9 autotransplanted canine lungs during perfusion in situ. Dopamine (up to 13,5 gamma/kg BW, rapid injection) acts as a vasoconstrictor by alpha-receptor stimulation. Vasodilative effects could not be registered neither by very small amounts of dopamine nor during alpha-blockade with phentolamine. No difference could be detected between the vascular reactions of normal and autotransplanted lungs.

Animals↗

[Clinical experiences with dopamine after heart surgery].

15 patients have been treated with dopamine (2.0--6.0 gamma/kg/min) in the initial phase of cardiogenic shock after cardiac surgery. Indication was a systolic blood pressure of less than 85 mmHg associated with oligurie and peripheral vasoconstriction. 12 patients survived the cardiocirculatory crisis and the early postoperative period. Dopamine alone increased the arterial blood pressure in 6 patients from 52.4 to 80.1 mmHg and the urine flow from 25.2 ml/hr to 181.2 ml/hr. To obtain an optimal perfusion pressure additional application of Noradrenalin was used in 8 patients. In these patients the urine flow rose from 9.1 ml/hr to 131 ml/hr. In one patient no reaction, neither to dopamine, nor in combination with Noradrenalin was seen. The effect of pulse rate, central venous pressure and arterial oxygen tension has been discussed. Dopamine seems to be a useful substance in surgical patients with temporary cardiac insufficiency.

Adolescent↗

Behavior of the portal vein system in man after laparotomy.

At the end of an abdominal operation, a Teflon catheter was inserted into the portal vein, where it remained for nine days. Thus, blood samples could be withdrawn for analyses, and pressures could be recorded. The investigations were carried out in 41 patients who had a gastric or intestinal operation and had an uncomplicated postoperative course. The pressures in the portal vein and the arterioportal oxygen content difference were constant with 7 to 8 millimeters of mercury and by 2 volume per cent, respectively, during the period of all nine postoperative days. The pressure gradient between portal and central veins was about 6 millimeters of mercury. By infusing 350 to 500 milliliters of dextran 60 on day one or two postoperatively, the cardiac output was elevated about one-third, the central venous pressure increased from 0.9 to 4.9 millimeters of mercury and the portal venous pressure increased from 7.8 to 9.7 millimeters of mercury. This means that the pressure difference between the portal and central veins diminished. Simultaneously, the oxygen content difference between the systemic and pulmonary artery decreased from 4.7 to 3.3 volume per cent and between the systemic artery and portal vein, from 1.8 to 1.3 volume per cent. By assuming a constancy of the oxygen consumption in the region of the mesenteric circulation during infusion, it can be calculated from the behavior of the arterioportal oxygen content difference that the flow increase in the portal vein nearly equals that of cardiac output. The physical transhepatic resistance decreased about 50 per cent.

Cardiac Output↗