Biomedical subjects

A Uysal

Publications and source records attributed to A Uysal.

64 records · Page 4Linked to original sources

PubMed1994

Bovine spongiform encephalopathy in Germany.

Bovine spongiform encephalopathy (BSE) has been described as an epidemic central nervous disorder in cattle from the United Kingdom. The disease is thought to have emerged by an interspecies transmission of the scrapie agent of sheep to cattle, after feeding scrapie-contaminated meat and bone meal (MBM). The disease has caused substantial economic losses for the British cattle industry. Because of strict veterinary regulations for the import of adult British cattle by the European Union and for MBM by most of the member states the spread of BSE to continental Europe could be efficiently controlled, and only few cases have been described outside the UK. Here we report the first German case of BSE diagnosed in a Scottish Highland cow. The affected cow was imported into Germany before the import ban for cattle from the UK was implemented. BSE was confirmed by histopathology, immunohistochemistry, animal experiments, immunoblotting and by electron microscopic detection of scrapie-associated fibrils (SAFs).

Animals↗

PubMed1993

Establishment of cell lines from bovine brain.

As shown by immunocytochemistry, 16 cell lines of neuronal, oligodendroglial or neuronoglial origin have been established from bovine fetal brain by immortalization with SV40 virus and cloning in soft agar. The cell lines were characterized according to their cell surface markers using mono- and polyclonal antibodies.

Animals↗

PubMed1993

[Handling of unconventional pathogens].

This article summarizes decontamination problems in handling transmissible spongiform encephalopathies (TSE) in the field of human pathology. The combination of chemical (i.e. 1 M NaOH, 1 h, room temperature) and physical (i.e. autoclaving for 30 min at 131 degrees C) decontamination methods was proven to be suitable for instruments and other materials. Als for the autopsy of suspected TSE patients, safety measures have to be taken. The brain preparation, in particular, represents a considerable risk which must be minimized by appropriate safety measures. Conventional formaldehyde fixation does not decontaminate tissues! Embedding, cutting, deparaffinization and processing or staining have to be done with cautions; members of staff must be aware of the danger. After the handling of suspect materials, the hands should be washed without brushing the skin. In the case of percutaneous inoculation the injury must be decontaminated immediately using iodine- or phenol-containing preparations, 0.5 M NaOH or 1:3000 potassium permanganate.

Autopsy↗

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↗

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

[Detection of cells with phenotype of multiple drug resistance in myeloproliferative disorders before the treatment].

The expression of the multidrug resistance (MDR) phenotype is connected with the overexpression of P-glycoprotein. By applying the immunocytochemical assay we have demonstrated that in myeloproliferative diseases (AML, ALL, MDS, CGL), in single cases, in smear preparations from the peripheral blood and bone marrow the cells with MDR-positive phenotype can be detected in the material obtained from patients before therapy, and without clinically and anamnestically known exposure to cytotoxic or immunosuppressive drugs. This finding has demonstrated the presence of subpopulations of MDR-positive cells in leukemias and myelodysplastic syndromes already before therapy, and, furthermore, has evidenced that a positive MDR phenotype is not necessarily associated with a malignant phenotype of a malignant cell transformation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1989

Detection of cells with multidrug-resistant phenotype in myeloproliferative disorders before therapy.

The expression of the multidrug resistance (mdr) phenotype is connected with the overexpression of the P-glycoprotein. By applying the immunocytochemical assay, we have demonstrated that in myeloproliferative diseases (AML, ALL, MDS, CGL) in single cases in smear preparations from the peripheral blood as well as from the bone marrow P-glycoprotein-positive cells, respectively, cells with mdr-positive phenotype can be detected in the material obtained from patients before therapy and without clinically and anamnestically known exposure to cytotoxic or immunosuppressive drugs. In the control group of probands without hematologic disorders and also without clinically or anamnestically confirmed contact with cytotoxic or immunosuppressive drugs, we have found P-glycoprotein-positive subpopulations of cells with positive mdr phenotype in a few cases as well. The uniqueness of our results lies in the fact that this finding demonstrates the presence of subpopulations of mdr-positive cells in leukemias and myelodysplastic syndromes before therapy, and furthermore makes evident that a positive mdr phenotype is not necessarily associated with a malignant phenotype or a malignant cell transformation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1987

Penile agenesis--a case report.

A case of penile agenesis is presented. Psychological and surgical problems encountered in such cases are emphasised. We feel justified in reporting this case due to its rare occurrence and presence of only about 40 reported cases in the literature.

Humans↗

PubMedDate not supplied

Multidrug resistance in heart transplant patients: a preliminary communication on a possible mechanism of therapy-resistant rejection.

Multidrug resistance refers to a complex cellular phenotype, the hallmark of which is cross-resistance to multiple drugs, for example, chemotherapeutic agents, that are unrelated to the selecting agent in structure, cellular target, and mode of action. The expression of this multidrug resistance is connected with the overexpression of P-glycoprotein. By applying the method of immunocytochemical assay, we have demonstrated the appearance of the multidrug-resistant phenotype (P-glycoprotein+ cells, multidrug-resistant cells) in mononuclear cells of the peripheral blood from 32/49 patients receiving triple-drug (azathioprine, steroids, cyclosporine) immunosuppressive therapy after heart transplantation. In the group of patients showing not only the presence of cells with multidrug-resistant phenotype in the peripheral blood, but also a significant increase in the number of these cells during the interval of observation (0 to 767 days)-16/32/49 cases--a significantly increased incidence of acute rejection episodes could be demonstrated. This supports the hypothesis of a possible existence of a therapy-resistant form of acute rejection, with an involvement of mechanisms of multidrug-resistance playing a role in its causal development.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Some aspects of changed histopathologic appearance of acute rejection in cardiac allografts after prophylactic application of OKT3.

The histopathologic findings of therapy-requiring acute rejection in the cardiac allograft observed in endomyocardial biopsy specimens taken from patients under prophylactic administration of OKT3 show certain differences in comparison with the classic description of acute rejection. These differences are characterized above all by a distinctly reduced cellularity of the infiltrates, with a relative decrease of T cells, as well as edema and retrogressive changes, up to necroses of myocytes with marked fragmentation; some patients also have increased vascular reactions. Furthermore, an earlier occurrence of and an increased frequency of changes corresponding to the so-called lymphoma-like lesions ("Quilty" effect) were observed in patients who received immunosuppressive prophylaxis with OKT3. The changed histopathologic findings of therapy-requiring acute rejection under prophylactic application of OKT3 may, to a certain extent, explain the discrepant results reported by different transplant groups with respect to the frequency of rejection episodes and the time when the first episode of therapy-requiring rejection occurs after heart transplantation.

Antibodies, Monoclonal↗