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Biomedical subjects

J Cremer

Publications and source records attributed to J Cremer.

At least 91 records · Page 5Linked to original sources
PubMed1992

Myocardial preservation with the UW solution. First European results in clinical heart transplantation.

In recent years, there is a growing body of evidence that the University of Wisconsin (UW) solution offers many advantages in organ preservation with regard to preservation quality and time. We, therefore, conducted the first European prospective, randomized, clinical trial comparing myocardial performance after preservation with UW and St. Thomas Hospital (ST) solution. Preliminary results indicated superior heart function after preservation with UW solution.

Adenosine↗
PubMed1992

Cytotoxicity of cyanobacterium Microcystis aeruginosa.

Cytotoxic effects of crude extracts and fractions of the purification steps towards Microcystin-LR (MCYST-LR) were investigated in vitro. Cytotoxicity was evaluated by measure of lactate dehydrogenase liberation of Chang liver cells and by hemolysis. Crude extracts of strain PCC 7806 damaged the cells within a few minutes. In contrast, MCYST-LR did not show any detectable cytotoxic effects. The cytotoxic activity could be related to a heat-labile substance with a molecular weight of about 30,000 Da.

Animals↗
PubMed1992

Preoperative corticosteroids. A contraindication to lung transplantation?

Regular preoperative application of corticosteroids has been considered as a contraindication to lung transplantation for fear of an increased risk of postoperative morbidity and mortality. Recently, however, we have accepted patients for transplantation in whom treatment with steroid medication could not be terminated preoperatively. Up to February 1991, 27 unilateral and bilateral transplantations in 26 patients were analyzed. Corticosteroid therapy was discontinued at least three months prior to transplantation in 13 patients (group 1), whereas in 14 cases, the patients continued their daily corticosteroid therapy to the time of transplantation (prednisolone, 0.1 to 0.3 mg/kg/day; group 2). There were no significant differences between the groups with respect to sex, age, diagnosis, or type of transplantation. One limited bronchial dehiscence occurred; the incidence of postoperative bronchial stenosis was identical in both cohorts; one patient died in each group. In conclusion, no increased morbidity or mortality could be found following lung transplantation with regular preoperative administration of prednisolone up to 0.3 mg/kg/day. Thus, patients who cannot be weaned from their steroid medication but who otherwise are acceptable candidates should not be excluded from lung transplantation.

Adolescent↗
PubMed1991

Hyperacute rejection in heart allografts. Case studies.

Hyperacute rejection in orthotopic heart allografts is a rare event. In our material from a total collective of 524 heart-transplanted patients, we have observed two cases of hyperacute rejection, which are presented in this case report. Histopathologically, this entity is characterized above all by the following triad: pronounced edema, hemorrhages, and regressive changes up to necroses of myocytes. Besides the well-known risk factors, our report draws attention to two further factors possibly associated with an increased risk of hyperacute rejection: 1) repeated cardiac surgery prior to the transplantation, and 2) presence of identical viral genomes in recipient's and donor's heart.

Adult↗
PubMed1991

Organ preservation for heart-lung and lung transplantation.

One of the most important restrictions in the field of heart-lung- and lung-transplantation remains the limited ischemic tolerance of the lung. From December 1987 through February 1991, 44 patients underwent either single-, double-, or heart-lung-transplantation. All organs were harvested in multiorgan procedures. For the first 4 patients core cooling of the donor was used. For the rest pulmonary artery flush with modified Euro-Collins solution and prostacyclin was employed. Ischemia time varied from 3-6.5 hours (mean 241; 176-390 minutes). Hearts were arrested with St. Thomas cardioplegia. Oxygenation was satisfactory at 24 hours: p O2 greater than 100 mmHg, FI O2 less than 30% oxygen. It is concluded that for lung preservation modified Euro-Collins solution and prostacyclin for flush perfusion of the pulmonary artery will result in excellent lung function early postoperatively with ischemic times up to 6.5 hours. This method seems advantageous compared to others due to the limited surgical and instrumental needs.

Adult↗
PubMed1991

Genetic and biochemical analysis of the aspartokinase from Corynebacterium glutamicum.

The lysC/asd gene cluster of Corynebacterium glutamicum ATCC 13032 was cloned and sequenced. The lysC locus coding for aspartokinase consists of two in-frame overlapping genes, lysC alpha encoding a protein of 421 amino acids (Mr 44,300) and lysC beta encoding a protein of 172 amino acids (Mr 18,600). The C. glutamicum aspartokinase was purified and found to contain two proteins of Mr 47,000 and Mr 18,000. A C. glutamicum mutant expressing a feedback-resistant aspartokinase was shown to be changed in a single base pair of the lysC beta gene, leading to an amino acid exchange in the beta-subunit of the aspartokinase. In addition, the identified mutation was found to be responsible for the enhanced expression of the asd gene located downstream of lysC.

Amino Acid Sequence↗
PubMed1991

Extracorporeal membrane oxygenation (ECMO): extended indications for artificial support of both heart and lungs.

Extracorporeal membrane oxygenation (ECMO) was used to achieve temporary artificial support in cardiac and pulmonary function in 22 patients from 1987 to September 1990. Standard indications were postcardiotomy cardiogenic shock (n = 4), neonatal (n = 1) and adult respiratory distress syndrome (n = 4). ECMO was also used for extended indications, such as graft failure following heart (n = 11) or lung transplantation (n = 2). In six of these cases ECMO was instituted as a bridge device to subsequent retransplantation of either the heart (n = 4) or one lung (n = 2). One out of nine patients supported by ECMO for standard indications, and two out of 13 patients supported for extended indications are long-term survivors. This series illustrates the results with ECMO in emergency situations, in patients under immunosuppressive protocols, or in patients with advanced lung failure requiring almost complete artificial gas exchange. In such complex situations, ECMO does provide stabilization until additional therapeutic measures are in effect. ECMO cannot be recommended for postoperative cardiogenic shock but short-term ECMO support is an accepted method in most cases with graft failure or pulmonary failure or other origin.

Adult↗
PubMed1991

[Hemodynamic characteristics of heart transplant patients in the early postoperative period].

In spite of good long-term results, heart transplantation continues to carry a significant risk of hospital mortality (about 10%). Among cardiac deaths, right-heart failure due to an elevated pulmonary vascular resistance represents a main contributing factor. Since no quantitative data on the hemodynamic situation early after transplantation are available, we monitored 27 heart transplant patients during the first four postoperative days. Data derived from right-heart catheterization, dosages of catecholamines and vasodilative substances were measured at 2, 4, 16, 24, 48, 72, and 96 h after the operation. Oxygen consumption and serum lactate levels were determined until 48 h postoperatively. During that time cardiac output remained constant (2 h: 6.6 +/- 1.4 l/min). The dosage of catecholamines was highest immediately after transplantation (2 h: 0.229 +/- 0.136 micrograms adrenaline/kg/min) and could be reduced thereafter. Highest values of pulmonary vascular resistance were obtained 2 h postoperatively (160 +/- 48 dyn.s.cm-5). This early postoperative situation may result in the development of right-heart failure as observed in two patients who died despite the use of prostacycline on the third and eighth postoperative days. To counteract the systemic vasodilative side-effects of prostaglandins, temporary atrial pacing seems to be useful. In our study atrial stimulation led to an increase of cardiac output and a moderate elevation of mean arterial blood pressure. Only a poor correlation between pre- and postoperative (2-h) pulmonary vascular resistance data could be observed. In most patients the pulmonary vascular resistance decreased during the postoperative course. This was not the case in patients with fixed pulmonary hypertension. We, therefore, conclude that preoperative diagnostics should be refined to recognize patients at risk in order to reduce postoperative mortality.

Adult↗
PubMed1990

Distant organ procurement in clinical lung- and heart-lung transplantation. Cooling by extracorporeal circulation or hypothermic flush.

The scarcity of suitable donors for single lung and heart-lung transplantation calls for methods of medium-term pulmonary preservation to allow for distant organ procurement. At our institution, the first five grafts (four heart-lung, one single lung) were cooled by means of a transportable extracorporeal circulation unit, while the last eight grafts (four heart-lung, four single lung) were flush-perfused with modified cold Euro-Collins solution. The technique of extracorporated circulation included aortic and right atrial cannulation and cooling to 12 degrees-14 degrees C (rectal temperature) using a bubble oxygenator. Bypass times ranged between 41 and 52 min. Following excision, the organs were transported in ice-cold donor blood for ischemic times from 171 to 310 min. For cold flush preservation, simultaneous coronary (cold St. Thomas's solution) and pulmonary artery perfusion (Euro-Collins solution, 50 ml/kg over 4 min) were initiated simultaneously. The organs were transported in cold Euro-Collins solution for ischemic times of 175 to 270 min. In heart-lung transplantations the first postoperative arterial PO2 upon arrival at the intensive care unit was 120 +/- 38 Torr in the extracorporeal circulation and 140 +/- 38 Torr in the Euro-Collins solution group. Six of eight patients were extubated within 48 h after cardiopulmonary grafting. We conclude that pulmonary function following heart-lung or single lung preservation with simple hypothermic flush is as good or better than that following extracorporeal circulation. Since distant organ retrieval is much more convenient without the latter, preservation using Euro-Collins solution is preferred.

Adolescent↗
PubMed1990

T-cell lymphoma after heart transplantation.

A 26-year-old woman who had undergone orthotopic heart transplantation because of dilative cardiomyopathy received a triple-drug immunosuppressive regimen (cyclosporine A, azathioprine, and prednisolone). During her relatively frequent episodes of acute rejection, she was treated with methylprednisolone and repeated application of ATG. A short time before the patient's death, a fine-needle aspiration of the liver revealed the cytologic diagnosis of a malignant pleomorphic medium-size cell non-Hodgkin's lymphoma of a higher grade of malignancy. Immunosuppression was reduced, and the patient died in cardiogenic shock related to a histologically confirmed episode of severe acute rejection 264 days after the transplantation. On autopsy, the malignant lymphoma previously diagnosed by fine-needle aspiration cytology was found to be present in the liver as the only extranodal localization. The immunohistologic analysis of the immunophenotype specified the lymphomatous neoplasia as a T-cell lymphoma. The particular importance of this case is that it is, to our knowledge, the third case of proven T-cell lymphoma following organ grafting documented in the literature and the first case described in a cardiac allograft recipient.

Adult↗
PubMed1990

[Unilateral lung transplantation].

For patients with terminal pulmonary fibrosis unilateral lung transplantation offers a new therapeutic option. At the Hannover Medical School 5 patients have been successfully treated by single lung transplantation. In 3 patients a left, and in 2 patients a right lung transplant was performed. One patient required intraoperative support by cardiopulmonary bypass. Bronchial omentopexy was used in all instances. Currently all patients are alive. A marked improvement of pulmonary function parameters was seen in all cases. The patients are all able to lead a normal life.

Adult↗
PubMed1989

[Indications and results of orthotopic heart transplantation in coronary heart disease].

In parallel to increasing numbers of orthotopic heart transplantations performed during recent years, the proportion of patients with preexisting ischemic cardiomyopathy (ICM) enlarged. The present study examined peri- and postoperative risk factors and the prognosis of patients with coronary artery disease after orthotopic heart transplantation in comparison to a group with dilatated cardiomyopathy (DCM). This comparison revealed a higher risk of severe rejection episodes in patients with coronary artery disease, whereas infections were not more frequent. Graft atherosclerosis was found in a higher incidence in patients with preexisting ICM than in the DCM group. The overall incidence of graft atherosclerosis was less than 10% at one and at two years after orthotopic heart transplantation. Postoperative renal function was more impaired in the group of ICM patients, although blood levels of cyclosporine A were lower in this group. In the ICM group one and two year survival rates were 75% and 74%, respectively. Although survival rates are lower in this patient group, if compared to DCM patients (84% and 83%), orthotopic heart transplantation seems to be acceptable therapeutic alternative for endstage coronary artery disease.

Adult↗
PubMed1989

Left ventricular function, tricuspid incompetence, and incidence of coronary artery disease late after orthotopic heart transplantation.

Functional results and data concerning the incidence and severity of graft atherosclerosis (GASC) and tricuspid incompetence (TI) in the intermediate term after orthotopic heart transplantation (HTX) are still striking. We examined 92 patients 1, 2, and 3 years after HTX by right and left heart catheterization in order to evaluate pump function, the status of the coronary arteries and the extend of TI, using a double indicator thermodilation technique. Mean left ventricular volumes and ejection fraction were normal 1 and 2 years post-transplant. The incidence of GASC was 8/87 (9.2%) at 1, and 11/92 (12%) at 2 years. It was more frequent (16%) in patients with preexisting coronary artery disease (IHD) than in patients with underlying dilative cardiomyopathy (DCM) (11%). At the end of the 1st postoperative year, 62% of patients were free of TI, whereas only 38% had normal valve function 2 years posttransplant. In 9/14 (64%) of patients, consecutively assessed at 1 and 2 years, TI had increased between both investigations. Preoperative haemodynamics, the number of endomyocardial biopsies and rejection episodes as well as preoperative cardiac size did not correlate with TI. Left ventricular volumes and ejection fraction are normal in the intermediate term after HTX. The incidence of GASC was less than 10% at 1 year and did not significantly increase thereafter. TI is a frequent and yet unexplained finding after HTX showing a considerable tendency to increase with time, but with little or not haemodynamic consequence.

Adult↗