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Biomedical subjects

W Hermann

Publications and source records attributed to W Hermann.

At least 55 records · Page 3Linked to original sources
PubMed1984

Activatable esterase activity of murine natural killer cell--YAC tumour cell conjugates.

Natural killer (NK) cells have been obtained from mouse spleens and grown in vitro. These cells: retained cytotoxicity against YAC targets; and were homogeneous as judged by morphology and surface markers. The alpha-naphthol acetate esterases (ANAE) and diisopropyl-fluorophosphate (DFP)-binding proteins of NK cells, YAC cells and NK-YAC conjugates have been examined. Ultrastructural cytochemistry indicates that NK cells have two types of ANAE: an enzyme primarily associated with the granule externum and an activatable ANAE associated with the granule internum. Both of these activities are inhibited by DFP. The activatable ANAE appears during incubation of NK cells with YAC cells. DFP-binding proteins were examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis and autofluorography. NK cells and YAC cells have major DFP-binding proteins of 35 X 10(3) and 20 X 10(3) Mr, respectively. NK-YAC conjugates had a new band at 55 X 10(3) Mr. This new protein may be identical to the activatable ANAE described above. Our studies provide evidence for an NK cell esterase that becomes activated when incubated in the presence of tumour cells. This esterase may be related to the cytolytic mechanism.

Animals↗
PubMed1983

[Aortic valve replacement in cardioplegic heart arrest].

The St. Thomas cardioplegic solution was introduced in our clinic in January, 1980. Before, aortic valve replacements were carried out using cold ischaemic cardiac arrest as myocardial preservation technique. In 62 aortic valve replacements performed since January 1980, there was no hospital mortality. Moreover, there were fewer intraoperative and postoperative complications. Intraoperative serum potassium was not essentially elevated after cardioplegic perfusion of the heart, although most of the cardioplegic effluate passed into the extracorporeal circulation. Postoperative serum-creatinphosphokinase levels were significantly higher after cold ischaemic arrest than after cardioplegia.

Aortic Valve↗
PubMed1982

[Infrared contact coagulation for hemostasis in liver and spleen].

With infrared contact coagulation (ICC) hemostasis of hepatic and splenic tissue is achieved by coagulation and mechanic compression of the bleeding surface. Thus, an eventual loss of energy due to a thick layer of blood can be avoided. After coagulation, the anti-adhesive effect of the cap of the ICC device prevents fresh bleeding. After experimental incisions on liver and spleen of various animal species hemostasis could be achieved quickly by application of ICC. Postoperative observation and histologic investigations were carried out until the 80th postoperative day. Hemostasis was observed in all cases, there were no signs of recidivant bleeding at relaparotomy. A slow absorption f necrotic tissue was observed. This could be a disadvantage regarding long term wound healing.

Animals↗
PubMed1982

[Role of the pericardium in acute volume overload].

The function of the pericardium in acute volume overloading may be defined as protection against ventriculo-atrial regurgitation at high filling pressures, limiting transmural pressures and, therefore, protecting against ventricular distension as well as supporting the filling of the ventricles by suction in the systolic contraction. Thus, it may be important to close the open pericardium carefully after open heart surgery. Pericardial drainage should prevent cardiac tamponade.

Animals↗
PubMed1982

[Hemostasis in the liver induced with tissue glue - comparison of 2 glue-component combinations].

After experimental hepatic resection in rabbits and piglets, haemostasis was achieved by using two types of tissue glue - fibrin glue and gelatin-resorcin-formaldehyde glue (GRF-glue). With both glues, an elastic adhesive film could be produced. Fibrin glue was completely absorbed by granulation tissue at the 11th postoperative day. After using GRF-glue a toxic necrosis and a subsequent demarcation of necrotic tissue could be observed, with the adhesive substance being not absorbed after 11 days. When used together with a collagen fleece, fibrin glue was not spilled away by tissue haemorrhage. Therefore it seems to be especially suited for haemostasis on the liver. With both glues, no leakage was observed after raising the portal vein pressure to 300 mm Hg during in vitro experiments.

Animals↗
PubMed1981

[Clinical experience in a case of orthotopic liver transplantation by use of an atypical caval vein anastomosis (author's transl)].

The two main indications for liver grafting are primary malignancy and parenchymatous liver disease. In both cases orthotopic transplantation remains the preferred technique. Since graft rejection was considered not to be the main problem in clinical liver transplantation, recent improved survival rates were reported to be due to a more aggressive diagnostic management and consequent treatment of postoperative complications nonrelated to graft rejection. Because of the limited number of organs available for organ grafting sometimes technical modifications may become necessary. This was the case in a 40-year old male patient suffering from primary malignant hepatoma. The donor was a child, and during operation a great difference between organ size and length and diameter of the hepatic vessels became evident. Orthotopic transplantation was performed using an unusual method of caval vein anastomosis. Initially the patient did very well, but later on liver function deteriorated and the patient died in the eighth postoperative week because of hepatic artery thrombosis. The autopsy showed that all other vascular anastomosis were patent and no signs of portal hypertension were evident. The surgical technique used in this case is described in detail and some interesting aspects are discussed.

Adult↗
PubMed1981

[Centrifugal blood pump (animal experiments) (author's transl)].

A new centrifugal blood pump (Medtronic 1861), suitable as an extracorporeal left ventricular assisting device was tested in vitro with respect to its efficiency and haemolysis. Cannulation was carried out by applying the Zwart technique. Additionally, comparative investigations into haemolysis were performed by using the centrifugal pump and an occlusive roller pump at equal output levels. Moreover, the haemodynamic efficiency of the centrifugal pump in combination with the Zwart cannulation technique was tested in landrace pigs. When the described centrifugal pump and tube system were used, a sufficient pump output and a low rate of early haemolysis could be observed. By applying the centrifugal pump together with the Zwart cannulation technique and conical tubes specially shaped, a complete relief of the left ventricle could be attained experimentally.

Assisted Circulation↗
PubMed1980

[Surgical treatment of congenital heart disease in infants without use of extracorporeal circulation (author's transl)].

Between 1970 and 1978 135 infants with congenital malformations underwent operations due to congestive heart failure, progressive pulmonary hypertension, and severe cyanosis. Of them, 63% were acyanotic; 68% of all operations became necessary during the first 6 months of life. The late mortality rate was 5% and the hospital mortality rate 17%. A remarkably higher operative risk was found during the first 6 months of life. Ligation of patent ductus arteriosus as the most common lesion was done with a mortality rate of 2.5% which is comparable to the risk of late repair in childhood. Pulmonary artery banding could be performed in all acyanotic malformations with a mortality rate of 17% and of 12.5% in isolated VSD (including debanding and VSD closure in several cases). Coarctation of the aorta was corrected with a overall mortality rate of 26%. Because of a recurrence rate of 20%, the authors think that operations are only indicated in symptomatic cases of coarctation. In complex cyanotic malformations, a higher operative risk was observed in both pulmonary artery banding (38%) and shunt operations (44%). If surgical treatment is necessary, the earlier, the better.

Age Factors↗
PubMed1979

[Age at correction and postoperative hypertension in isolated coarctation of the aorta (author's transl)].

A follow-up study of 46 cases of isolated coarctation of the aorta (age at surgical treatment 1 to 48 years) is presented. The late postoperative blood pressure was the higher the later surgical treatment was carried out. When surgical treatment was carried out at an age of more than 14 years, an increase of the residual hypertension rate was observed. A relatively low rate of residual hypertension can be expected after correction at about 6 to 10 years. Surgical treatment in infancy does not seem to have beneficial effects since according to other reports correction at this age does not reduce the residual hypertension rate essentially. Apart from the elevated residual hypertension rate surgical treatment at an advanced age generally has a lowering effect on blood pressure values.

Adolescent↗
PubMed1979

[Displacement of electrodes in pacemaker patients (author's transl)].

The implantation of special electrodes is indicated by right ventricular dilatation and especially by electrode displacement. For this purpose the MIP 2000 has been used with good results. It is the electrode preferred currently, but it may be replaced in future by the screw electrode which is now being clinically tested. Because of the danger of uncontrolled ventricular perforation the indication for operative myocardial implantation of pacemaker electrodes should be restricted especially in cases of myogenic dilatation of the heart.

Cardiac Surgical Procedures↗