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Biomedical subjects

F Unger

Publications and source records attributed to F Unger.

At least 109 records · Page 6Linked to original sources
PubMed1978

Clinical application of the ellipsoid left heart assist device.

The ellipsoid left heart assist device (E-LVAD) was implanted in eight patients suffering from intraoperative heart failure. It was not possible to remove these patients from extracorporeal circulation following an intracardiac procedure; therefore, implantation of the E-LVAD was performed during extracorporeal circulation. The inflow connector was pushed forward from a purse-string suture on the right superior pulmonary vein, across the mitral valve and into the left ventricle. The outflow connector was joined to the ascending aorta. In two patients, the artificial heart chamber was removed after complete recovery of the circulation; these patients, however, later died. In six other patients, untreatable right heart failure developed and these patients died with the pump in place. It is concluded, therefore, that the right heart must also be mechanically supported during postoperative heart failure.

Adult↗
PubMed1977

Rhabdomyosarcoma of lung arising in congenital cystic adenomatoid malformation.

An asymptomatic congenital cystic adenomatoid malformation of lung discovered at age 18 months, and unchanging for 14 months prior to its removal, was found to harbor a small embryonal rhabdomyosarcoma following excision. With lobectomy and chemotherapy, the tumor-free interval has now exceeded three years. The case represents a well-documented occurrence of malignant tumor arising within a congenital malformation, an association that is unlikely to be the result of chance.

Female↗
PubMed1977

[Design and haemodynamic evaluation of the ellipsoid heart for total heart replacement].

Thromboembolism is a complication which represents a major limiting factor in animals with long-term postoperative survival periods following total artificial heart replacement. Thrombi are formed on the artificial valves, the biomaterials and in stagnation areas within the artificial ventricles. In design planning the stagnation areas should be avoided as well as major turbulences. The filling volume should be maximally used for the stroke volume and the epicenter of the membrane should be underneath the valve areas. The ellipsoid heart eliminates stagnation areas and the stroke volume is 82% of the filling volume. The maximum cardiac output is 15.8 l/min. The ellipsoid heart was implanted in 20 female calves; the maximum length of survival was 213 hours. There was no compression of the inferior vena cava and the heart fitted well into the chest of the animals. The cardiac output, self-regulated in the sense of Starling's law, was adequate to perfuse the animals and to allow moderate exercise such as standing. The arterial pressure curves show normal physiological activity. The curves in both atria are unphysiological, owing to relative insufficiency of the valves. The limiting factors were pulmonary insufficiency and surgical complications. The ventricles showed no thrombus formation -- except in one case, in which faulty material was the predisposing cause. It was possible to develop an automatic driving system on the basis of these experiments. Regulation occurred by means of gas flow control in the driving tubes, whereby the form of the gas flow curve provides information on position of the membrane. As soon as the membrane has reached the end-diastolic position, systole is triggered off and lasts until the end-systolic position is reached. If the venous return is increased, the ventricles are filled more rapidly and the heart is driven at a higher rate. One part of the ellipsoid heart is used as ventricle for assisted circulation. The left ventricle is cannulated via the left appendage or the apex. The ventricle relieves the left heart to a large extent and the cardiac output is taken over by the pump placed in a paracorporeal position. The blood is directed back into the thoracic aorta.

Animals↗
PubMed1977

[Amnioscopy as a routine method--results of 9 years experience].

In the 9-years period (1967 to 1975) we are using the amnioscopy increasing generously. Nevertheless the percentage on pathological findings of the amniotic fluid altogether and in the seperate groups of indication is nearly has been always the same. It is'nt exact correlation between the severity of the symptoms of risk and the occurrence of the pathological findings in the amniotic fluid. The grand reliability of the amnioscopy also follows from the material of ourselves: The perinatal mortality in the group of supervised pregnant women by amnioscopy is clear less than in the group of nonsupervised. That comes true to all three parts of perinatal mortality. Our own experiences speak in generous use of the optical evaluation of amniotic fuuid by was of screening.

Amnion↗
PubMed1977

An improved screen for use with the auto-plot perimeter.

The Auto-Plot perimeter is a projection perimeter designed for analysis of the central 30 degrees of the visual field. It supplies clean test spots, which can easily be varied in size and colour, and the results can be recorded rapidly. However, because the screen is flat, the size and illumination of the projected spots of light vary as the targets are moved outward from the fixation point. We have devised a very inexpensive curved screen which eliminates these disadvantages.

Humans↗
PubMed1976

[The importance of immune deficiency for the prognosis of purulent meningitis (author's transl)].

Morbidity and mortality of suppurative bacterial meningitis show a very constant behavior over many decades. The introduction of antibiotics certainly lowered the lethality considerably, but since then it has remained fairly unchanged at about 15-20%. However, in the principal groups of pathogens--meningococci, pneumococci, Haemophilus influenzae--antibiotic resistence plays no special role. The significance of disorders of defense against infections for the course of the disease has not yet been investigated. Of 92 children examined with purulent meningitis, 49 showed a selective antibody deficiency syndrome against bacterial antigens, 38 of 48 children investigated showed further disorders of bactericidal activity. The proportion of these disorders is particularly high in children with defective healing of a meningitis.

Austria↗
PubMed1976

[A new design for a totally artificial heart: the ellipsoid heart (author's transl)].

Thromboembolic complications represent the main limiting factor in cardiac replacement by totally artificial hearts in calves at present. Thrombus formation within artificial hearts is caused by the appearance of stagnation areas. The ellipsoid heart eliminates stagnation areas by virtue of its production as a one-piece membrane. The heart is driven pneumatically and functions as a diaphragmatic blood pump. The stroke volume is 178 cm3 and the maximal cardiac output 15.8l/Min. Three acute experiments demonstrated a high degree of haemodynamic efficiency without compression of, or interference with surrounding structures, especially the inferior vena cava or the right atrium.

Animals↗
PubMed1976

[Traumatic hämolysis of verious heart-lung-machines on oxygenators (author's transl)].

1250 protocols of heart-lung-machines, taken between 1962-1974, underwent a variance analysis. The results show that rollerpumps with high pumpvolumes (80 ccm) are not significantly lower hemolytic than rollerpumps with a pumpvolume of 40 ccm. The hemolysis stands in direct proportion to the blood flow. Membranoxygenators effect a less traumatisation than screen- and bubbleoxygenators. Furthermore the use of fresh ACD-blood shows a lower hemolysis than hemodilution and older ACD stored blood. Type and age of the vitium have no influence on the traumatic hemolysis. The use of the orthograde perfusion is significantly better than the retrograde perfusion; the use of blood-filters is no cause for traumatic hemolysis. The above mentioned results are in accordance to literature, but the facts cannot be objectivated that easily than in invitro experiments.

Adolescent↗
PubMed1976

Material and design factors in thromboembolization in total artificial heart recipients living 100-2,000 hours.

When total artificial heart (TAH) recipients live over 100 h it is possible to evaluate the thrombogenicity of design and biomaterials. In 20 consecutive TAH recipients of the Jarvik heart with Björk-Shiley valves we compared rough (Dacron fibril-coated Silastic) and smooth (Biomer and Avcothane) blood surfaces. The mean survival times with rough surfaces was 296 h, with smooth surfaces 545 h. The present designs necessitate a sharp angle junction between the diaphragm and housing, creating stagnation areas and turbulences which induce thromboembolization. The valve rings and struts are another constant source of thromboembolism. Of the 80 valves, 41% showed thrombus deposition independent of anticoagulation. The polyurethane surfaces, in contrast to the fibrilized surfaces, were very clean and free of thrombi at autopsy. The thromboembolization was not dependent on anticoagulation and platelet adhesiveness inhibitor in hearts with rough surfaces. Based on 20 experiments including 78- and 94-day TAH survivors (Avcothane and Biomer hearts), there is an indication of the need of a new ventricular design. The ultimate design should generate physiological pulse waves without turbulences or stagnation areas within the device.

Animals↗
PubMed1976

[Encephalitis and humoral immunity].

Fourteen children with viral infection of the central nervous system have been examined with respect to their function of humoral immunity. Serum concentrations of immune globulins have been measured and antibody titers determined. Iso- and hetero agglutinins as well as antibodies against diphtheria, pertussis, and tetanus if the children were vaccinated have been measured. Anti viral antibodies were tested if children reported the respective infection in their history. Selective antibody deficiency have been found in three children all of whom had normal serum IgG and two elevated IgM levels. These three children showed complications in the course of infection. Nine children had elevated serum IgM and titers of IgM-antibodies were also in or above the high normal range.

Antibodies↗
PubMed1975

[Long-term results in pacemaker therapy].

The range of age, life expectancy and problems of functional control in pacemaker patients, are reported. The results demonstrate the dependability of pacemaker treatment, provided that there is an adequate functional control. The life expectancy, in comparison with total population, was found to be similar.

Adolescent↗
PubMed1975

Thrombus generation within the artificial heart.

The sites of thrombus formation in the Jarvik III artificial heart were studied in 20 consecutive calf experiments. Identical design and implantation procedures were used with two different surfaces. The 10 anticoagulated calves receiving Dacron-fibrilized silicone rubber surfaces survived an average of 296 hours. In contrast, the 10 nonanticoagulated calves with smooth poyurethane hearts survived 545 hours. The polyurethane surfaces were constantly clean. However, the rough surfaces were coated with variable amounts of thrombi. The sharp angle between the diaphragm and housing contained varying amounts of thrombi deposits in 75 per cent of the cases. Thrombe deposition occurred on 41 per cent of the valves. These thrombe were the source of emboli into the kidney, brain, and lungs. Turbulences and stagnation areas generated thrombus formation. Anticoagulation did not prevent thrombus formation. It would appear that heart free of turbulence and stagnation areas must be designed to eliminate thromboembolism.

Animals↗
PubMed1975

[Partial replacement of the heart].

A ventricular-aortic blood pump was constructed for the functional replacement of the left heart. Hemodynamic experiments showed that the device was able to pump the total cardiac output in calves with a body weight under 85 kg. In these cases the myocardial oxygen consumption decreased to 40%. Laboratory findings in 5 longterm experiments revealed a complete adaptation of the body to the artificial organ up to 73 days.

Animals↗