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Biomedical subjects

Z Gregor

Publications and source records attributed to Z Gregor.

At least 55 records · Page 3Linked to original sources
PubMed1988

Serum aldosterone studies in 10 calves living for 2-5 months with a total artificial heart (TAH).

A group of 10 experimental calves that lived for 61-147 days with a TAH was used to study serum aldosterone levels by RIA with ALDOCTK-125 CEA Kit (Sorin Biomedica, Italy). The aldosterone levels were plotted against the serum sodium and potassium, body weight, CVP, urinary sodium and potassium and with hematocrit levels. In these experiments, three types of TAH (TNS-BRNO II, VII, and Rostock) were used. The levels of aldosterone were already high before the surgery and during the entire pumping period, which indicates the development of secondary aldosteronism. The study deals with the mechanisms that participate in the development of aldosteronism in each phase of the experiment with the TAH.

Aldosterone↗
PubMed1986

Control and driving of pneumatic total artificial hearts TNS-BRNO-II and -III in long-term experiments.

Hemodynamic analysis was carried out during long-term experiments with the pneumatic total artificial hearts TNS-BRNO-II and TNS-BRNO-III to determine standard methods of starting artificial hearts and criteria for their long-term operation in vivo. In long-term experiments, regulatory mechanisms automatically regulating the systole length and diastolic aspiration pressure have also been verified. Comparison of hemodynamic variables obtained from invasive measurements with pneumatic pressure curves permitted the control and monitoring of the experiment in its entirety by noninvasive methods only. The control of the artificial heart using the Chirasist TN 3 and Chirasist TN 4 was adapted to specific properties of the pumps, above all to the functions of the atypical inlet valves. The terminal stages of the experiments have shown that a 100-ml pump can ensure survival of experimental calves up to 210 kg body weight.

Animals↗
PubMed1986

Antibodies to herpes simplex virus type I in intraocular fluids of patients with acute retinal necrosis.

The intraocular fluids and sera from three patients with acute retinal necrosis (ARN) and from 120 age-matched controls were tested for the presence of antibodies to herpes simplex virus type I (HSV-I). Antibodies to HSV-I were detected in both intraocular fluids and sera of two cases, and in intraocular fluids alone in one case of ARN. Among 120 control patients undergoing routine intraocular surgery antibodies to HSV-I were detected in the sera of 85 (79.2%) but in the intraocular fluids of only two (1.7%). The presence of antibody within the eye may indicate local antibody production, antibody sequestration within the eye, or damage to the blood ocular barrier.

Adolescent↗
PubMed1983

Complete and core vitrectomies in the treatment of experimental posterior penetrating eye injury in the rhesus monkey. I. Clinical features.

A controlled trial of pars plana vitrectomy for posterior penetrating eye injury was done in a group of rhesus monkeys to compare the results of limited (core) and complete vitrectomies performed one day and two weeks after injury. Although core vitrectomy was technically easier and led to fewer operative complications, the frequency of traction retinal detachment was significantly higher than after a complete vitrectomy. There was no significant difference between eyes operated on one day or two weeks after injury.

Animals↗
PubMed1983

Combined posterior contusion and penetrating injury in the pig eye. III. A controlled treatment trial of vitrectomy.

A controlled trial of vitrectomy following combined experimental posterior contusion and penetrating eye injury was performed on a group of pigs at 1 day, 2 weeks, and at 10 weeks after the initial injury. Severe intraoperative haemorrhage occurred in 5 eyes operated on at day after injury and in one eye operated on at 2 weeks after injury, but no haemorrhage occurred when surgery was performed 10 weeks after injury.

Animals↗
PubMed1982

Blood-retinal barrier after blunt trauma to the eye.

The competence of blood retinal barrier at the level of retinal pigment epithelium (RPE) and retinal capillaries was studied 30 min, 24 h, 3 days, and 7 days after experimental blunt eye injury in the pig, using horseradish peroxidase (HRP). Leakage of HRP into the outer retinal layers was observed in association with disrupted RPE in the first three days after injury. No HRP leakage was seen 7 days after the trauma and the retinal vessels remained competent throughout the study. It is suggested that extracellular edema occurs in the early stages of commotio retinae due to the disruption of blood retinal barrier at the level of the RPE.

Animals↗
PubMed1982

Combined posterior contusion and penetrating injury in the pig eye. II. Histological features.

The main histological features observed after an experimental posterior contusion injury in the pig eye were haemorrhage from the choroidal vessels into the subretinal space and into the vitreous, uveal vessel dilatation, and an inflammatory reaction. These changes resolved during the first 2 weeks, and the subretinal haemorrhage was replaced by a fibrocellular membrane. The addition of a posterior penetrating injury resulted in fibrocellular proliferation at the wound site 6 days after injury and in formation of vitreoretinal traction membranes and subsequent traction retinal detachment. Posterior vitreous separation did not occur.

Animals↗
PubMed1982

Pars plana vitrectomy entry sites.

The histological features of vitrectomy entry sites were studied in a group of monkeys following pars plana vitrectomy for experimental posterior penetrating injury. The extent of fibrocellular proliferation and vitreo-retinal complications arising from the vitrectomy wounds were compared to the proliferation from a much larger penetrating trauma site after complete and partial (core) vitrectomies. Although scarring and complications were more severe following core vitrectomy, there was little difference on histological examination between fibrocellular proliferations from the vitrectomy entry sites and from the penetrating wound.

Animals↗