Search PubMed⌕ Search

Biomedical subjects

M Turina

Publications and source records attributed to M Turina.

At least 505 records · Page 28Linked to original sources
PubMed1979

[Early scanning electron microscopy changes of the surface of the leaflets of orthotopic transplanted glyceraldehyd-conditioned conus-pulmonalis xenografts. An experimental study in dogs].

The surface of the leaflets of orthotopic transplanted glutaraldehyd-conditioned conus-pulmonalis xenografts show when analysed by a scanning microscope the following constant changes. Within seconds the surface of the leaflets is covered by a grainy layer of proteins followed by fibrin threads. Cellular elements of the blood--like platelets, white blood cells, macrophages and microthrombi--are incorporated in the fibrin network. This leads, after several weeks to a fibrous layer especially over the stiff parts of the valve. No endothelium was seen even after 6 months.

Animals↗
PubMed1978

[Percutaneous transluminal dilatation of chronic coronary stenoses. First experiences].

The technique of percutaneous transluminal dilatation of coronary artery stenosis consists of a catheter system introduced via the femoral artery under local anesthesia. A preshaped guiding catheter is positioned in the orifice of the coronary artery and through this a dilatation catheter is inserted into the branches if the artery. This dilatation catheter (outer diameter 0.5--1.25 mm) is equipped with a sausage-shaped distensible segment (balloon) at the tip. The balloon is inflated to a pressure of 5 atm. This pressure compresses the atherosclerotic material in a direction perpendicular to the wall of the vessel, therby dilating the lumen. Up to now 29 patients have been treated with primary success in 23 (79%) and long-lasting success in 21 (72%). Three patients underwent emergency coronary surgery to avoid infarction. Dilatation is indicated in patients with disabling angina which jeopardizes their quality of life and with coronary lesions which are proximal, subtotal, concentric and non-calcified.

Angiography↗
PubMed1978

[Myocardial damage in coronary air embolism (author's transl)].

Haemodynamic changes after intracoronary air embolism (0,02 ml/kg air in the left coronary artery) were studied in 16 dogs. The air was introduced in 8 animals during cardiopulmonary bypass and in 8 animals without bypass. In both groups the air embolization caused acute ischemia with myocardial necrosis. Immediately after the injection the anterior wall became akinetic; 24 hours after injection CPK increased to more than 800 U. One half of the animals without cardiopulmonary bypass died during acute ischemia due to refractory arrhythmias; there was no mortality in the group with cardiopulmonary bypass. The left ventricular damage due to air embolization cannot be significantly reduced with cardiopulmonary bypass; the bypass only helps to "tide over" the animal during the period of acute ischemia.

Animals↗
PubMed1978

[Surgical treatment of active infective endocarditis (author's transl)].

Between 1965 and 1976 40 patients underwent valve replacement for active, infective endocarditis. The overall mortality rate was 32,5 per cent. Six patients died early (within 30 days) and 7 within the following 8 years. 11 patients developed paravalvular leckage. Eight of these 11 patients required reoperation. We suggest that all patients with active infective endocarditis who develop progressive heart failure, intractable sepsis or recurrent embolization should be subject to immediate valve replacement despite higher operative risk.

Adult↗
PubMed1978

[Clinical application of paracorporeal artificial ventricles (author's transl)].

A pneumatically driven artificial heart with tubular silicone rubber membrane and disc valves was used in four patients with intractable postoperative cardiac failure. The operation was performed through a median sternotomy: large cannulas were placed in both atria and blood was returned to aorta and pulmonary artery. In three patients the natural heart recovered and the artificial ventricles were removed. One patient died 6 weeks after the operation, the other two left the hospital in good condition. Profound postoperative heart failure can be reversed by the use of the paracorporeal artificial heart; the advantage of the system lies in the simplicity of its implantation and removal.

Evaluation Studies as Topic↗
PubMed1978

[Animal experiment evaluation of myocardial protection with a magnesium-asparaginate-procaine solution].

Cardioplegic myocardial protection with magnesium asparaginate procaine (Cardioplegin) is assessed in normothermic ischemia by left ventricular function curves. Different ischemic times (20, 30, 40, and 50 min) and different doses of Cardioplegin (2, 4, and 6 ml/kg) were studied in 68 mongrel dogs. Postischemic myocardial function was depressed in all experiments. However, in the Cardioplegin groups all animals showed signs of recovery and a significant, but not dose-related, hemodynamic improvement compared to the controls.

Animals↗
PubMed1977

[Surgical treatment of myocardial aneurysms. Indications and results].

The long term results of 95 left ventricular aneurysmectomies are presented. In 47 patients simultaneous aorto-coronary bypass surgery was performed. 53 patients presented preoperatively with congestive heart failure; 8 out of these died within the first postoperative month, while 5-year survival rate (actuarial method) was 52%. Two thirds of this patient group improved. None of the 42 patients without preoperative congestive heart failure died early. 5-year survival rate was 93% and subjective improvement was recorded in one half of this subgroup. Comparison of pre- and postoperative angiograms (40 patients) revealed an increase in left ventricular ejection fraction reflecting the removal of the non-contracting segment. The ejection fraction of the contracting segment of the left ventricle improved after aneurysmectomy, especially in patients with preoperative congestive heart failure. In conclusion, aneurysmectomy improves left ventricular function and the symptoms of heart failure; moreover, it prevents perforation of false aneurysms. Its effect on arrhythmias could not be determined conclusively. Angina may be improved by simultaneous aorto-coronary bypass surgery.

Angina Pectoris↗
PubMed1977

[Transvenous endomyocardial biopsy in the assessment of congestive cardiomyopathy].

UNLABELLED: Transvenous endomyocardial biopsy by the technique of CAVES and SHUMWAY was performed in 12 patients with the clinical, hemodynamic and angiographic findings of congestive cardiomyopathy (COCM). Coronary artery disease was ruled out by selective arteriography. Light and electron microscopic findings were correlated with a functional classification based on physical working capacity (PWC) and three left ventricular (LV) angiographic parameters (ejection fraction, end-diastolic volume, mean velocity of circumferential fiber shortening). PWC and the LV volumetric indices (vi) were determined in 52 patients and allowed the following grouping: group 1 with normal PWC and borderline VI (subclinical COCM); group 2 with normal PWC and decreased VI; group 3 with reduced PWC and severely depressed VI. Endomyocardial biopsy was successful in 10 out of the 12 patients. The grade of myocardial damage was assessed by 10 different criteria of typical morphologic abnormality. The myocardial damage score correlated closely with functional impairment as present in the three groups. Immunological fixation tests with the biopsy specimens revealed no antigen-antibody complexes. CONCLUSIONS: (1) right ventricular endomyocardial samples adequate for morphologic examination are easily obtained by transvenous biopsy; (2) in COCM, functional impairment parallels the extent of morphologic abnormalities although assessments of cardiac function were essentially confined to the left ventricle, whereas the morphologic specimens were obtained from the right ventricle.

Adolescent↗
PubMed1977

The principles and in vivo performance of the Edinburgh pivoted aerofoil-disc prosthetic heart valve.

Prototypes of the Edinburgh prosthetic heart valve, known from previous experiments in vitro to promote exceptionally smooth and undisturbed forward flow, have been shown here in canine experiments to possess hemodynamic characteristics not inferior to those of the Bjork-Shiley valve (a present standard of excellence). In addition, we report a low incidence of valve thrombus deposition among calves in which this prototype valve, fabricated from the conventional materials, Delrin and stainless steel, has been implanted in the tricuspid site for up to 100 days without use of anticoagulants. This suggests that the design of the valve is such as to render it of low thrombogenicity. The new valve is designed for fabrication throughout in vitreous or pyro-coated carbon, materials of very high inherent athrombogenicity. It appears from the results discussed here that the developed form of the prosthesis, composed wholly of these athrombogenic materials, is likely to have both acceptable hemodynamic characteristics and an exceptionally low tendency to form thrombus. The introduction of such valves promises to be very advantageous and the results given here appear to warrant their development as the next stage of this program.

Animals↗
PubMed1977

[Various blood-foreign body reactions in the heart-lung machine in heart valve replacement and aortocoronary bypass operations].

Blood-foreign material interaction in the pump oxygenator was studied by means of scanning electron microscopy in 3 patients undergoing heart valve replacement (HVR) and 3 patients undergoing coronary bypass operation (CBO). While polyvinyl tubes show an average deposit of 60 thrombi/mm2 with 20--40 microns in size in CBO, bloodgas interface during HVR causes increasing thrombotic deposits (375 Mcthr/nm2, 25--50 microns in size). Distal to the pump the volume of particles may rise up 250 micrometer in HVR and up to 80 micrometer in CBO. In a 35 micrometer pore arterial-line-filter (Pall-Corporation) platelet clumps up to 1 mm in size are removed from circulating blood in HVR, and up to 300 micrometer thrombi in CBO. According to different platelet deposit proximal to the filter, more and larger thrombi can pass through the filter in HVR. Distal to the pump thromboemboli of 30--60 (maximum 90) micrometer in size can be observed in HVR. Particles of 20--35 (maximum 60) micrometer in size may pass through the filter and enter into the patient's circulation in CBO. As the results suggest, extracorporal circulation is more harmful for patients undergoing HVR than for those undergoing CBO.

Blood Cells↗
PubMed1976

[Myocardial blood flow and oxygen consumption in the fibrillating and empty-beating heart].

Myocardial flow and oxygen consumption are reduced during cardiopulmonary bypass. In ventricular fibrillation both flow and O2 consumption are higher than in the empty beating heart; after the fibrillation flow remains elevated although O2 consumption decreases. Aortic pressure is the major determinant of the myocardial flow rate, especially in hemodilution.

Animals↗
PubMed1976

Evaluation of a fluid-controlled artificial heart.

The Zurich A. H. is a pneumatic drive biventricular cardiac prosthesis with tubular silicone rubber membrane, tilting discvalves, and fluid control system. Membrane position is monitored throughout the cardiac cycle to prevent systolic membrane collapse or insufficient diastolic filling. This A. H. was implanted in 25 dogs weighing 23-50 kg. In five animals, the A. H. performed satisfactorily for more than 24 hr. At an average flow rate of 60-90 ml/min per kg, the aortic pressure ranged from 80 to 100 mm Hg, and both left and right atrial pressures were within normal range. The animals were awake, and they breathed spontaneously after 24 hr; average plasma hemoglobin levels averaged 91 mg/100 ml, and platelet counts decreased to 65,000 cu mm. In three animals subjected to the A. H. pump for 24 hr, the A. H. was removed and replaced with a transplant. Adequate transplant function was obtained, but there were no long-term survivors. Adequate hemostasis, sepsis, and complex organ dysfunctions associated with prolonged pumping are currently the main biologic problems.

Animals↗
PubMed1975

[Evaluation of the interaction between blood and foreign material in the pump oxygenator during open-heart surgery in infants by scanning electron microscopy (author's transl)].

Scanning electron microscopy was used to elucidate the interaction between blood and foreign material in the pump oxygenator during open-heart surgery in 7 infants. The loss of platelets upstream of the blood pump is caused by thrombogenicity. The pump itself causes massive destruction of platelets and red blood cells; thromboembolie up to 100 mu and foreign body particles up to 200 mu are being detached from the wall of the tubing to a large extent. The particulate matter is trapped in arterial line filter. Particles up to 40 mu and cellular aggregates up to 60 mu can pass through the filter and enter the patient's systemic circulation.

Blood↗