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Biomedical subjects

P Fischer

Publications and source records attributed to P Fischer.

At least 271 records · Page 15Linked to original sources
PubMed1989

[Lung diseases caused by non-tuberculous mycobacteria in East Germany and Hungary].

Despite the decrease of new cases of pulmonary tuberculosis also between 1982 and 1986 an increase in nontuberculous mycobacteriosis can be seen especially in the GDR and also in Hungary. In 1986 the ratio of recognized lung diseases caused by nontuberculous mycobacteria to all newly diagnosed bacillary cases was 4.1% in the GDR and 2.2% in Hungary. In Hungary, M. xenopi was the most important potential pathogenic species of nontuberculous mycobacteria during the whole period, followed by M. kansasii. In the GDR at the beginning most cases of nontuberculous mycobacteriosis were caused by M. kansasii later, M. xenopi was most frequent. Most of the patients with nontuberculous mycobacteriosis were men older than 50 years of age.

Cross-Sectional Studies↗
PubMed1988

Regulation of class II MHC molecules on human endothelial cells. Effects of IFN and dexamethasone.

Human vascular endothelial cells normally do not express class II MHC molecules in culture. IFN-gamma has been shown to induce expression of class I and class II MHC molecules on endothelial cell cultures from umbilical cord. We could detect these Ag by FACS analysis when endothelial cells were cultured for 3 days in the presence of 200 to 1000 U/ml of rIFN-gamma. Among the class II MHC molecules, HLA-DR and -DP but not -DQ were consistently induced. Addition of rIFN-alpha-D/A to IFN-gamma-treated cells inhibited the expression of class II MHC but not class I MHC molecules. Furthermore, the inhibition was more pronounced when IFN-alpha-D/A was added before or simultaneously as IFN-gamma. Natural IFN-alpha also exhibited similar inhibition and its suppressive effect was abolished in the presence of anti-IFN-alpha antibody. On the contrary, dexamethasone, a known inhibitor of class II MHC molecules on murine macrophages, showed a slight enhancing effect on class II MHC Ag. These results suggest an immunoregulatory role for IFN-alpha on non-lymphoid cells and that controlling elements for expression of class II MHC molecules may be different on various cell types as well as species.

Dexamethasone↗
PubMed1988

The role of iron chelates on the selectivity of Fenton reagent in hydroxylation, N-demethylation, and sulfoxidation of cimetidine: a novel biomimetic model for the regioselectivity of cytochrome P-450.

The effect of iron chelates on the reaction of cimetidine with Fenton reagent [Fe(II)/H2O2] has been investigated. Iron chelates with high affinity to ferrous ions inhibited this reaction. However, iron chelates with high affinity to ferric ions selectively promote either hydroxylation, N-demethylation, or sulfoxidation of cimetidine. These results indicate that the oxidation of cimetidine with hydrogen peroxide activated by various chelated ferrous ions serves as a biomimetic model for the regioselectivity of multiple forms of cytochrome P-450 in the metabolism of cimetidine.

Cimetidine↗
PubMed1988

Nonspecificity of semantic impairment in dementia of Alzheimer's type.

Two psychometric tests designed to evaluate "verbal fluency" and "naming" as a measure of semantic memory were presented to 18 patients with Alzheimer's-type dementia, 16 other patients with multi-infarct dementia, and 14 age-matched control subjects. The diagnosis of multi-infarct dementia and Alzheimer's-type dementia was based on the commonly accepted criteria of the Diagnostic and Statistical Manual of Mental Disorders, ed 3. Although the patients with Alzheimer and multi-infarct dementias, respectively, suffered from a comparable degree of dementia (as determined by the Mini-Mental State examination), semantic memory was not specifically impaired in Alzheimer's-type dementia as opposed to multi-infarct dementia. In contrast semantic memory was correlated with the degree of dementia in both disease entities.

Aged↗
PubMed1988

Translocation 5;21 and interstitial deletion of chromosome 7 in a case of chronic myelomonocytic leukemia.

We report a case of chronic myelomonocytic leukemia with a translocation involving chromosome 5 and 21, namely, t(5;21)(q35.3;q22.1), and an interstitial deletion of the long arm of chromosome 7. High-resolution analysis at the 900-band stage has shown that the lesion in chromosome 7 is an interstitial deletion involving loss of the segments q22-q35 of the long arm of chromosome 7 and retaining the telomere.

Aged↗
PubMed1988

Weak associations in environmental epidemiology.

Several suggestions have been made to enhance study designs to strengthen weak associations. Among these are reduction of non-differential misclassification, and restriction of studies to populations with low underlying risk of disease, due to low exposures to other known determinants of the health effect under investigation. To some extent, these suggestions have been put to use in environmental epidemiology, and in this paper, some prospects and problems associated with these attempts are discussed using examples from our own research.

Air Pollutants↗
PubMed1988

Localization of Nitrogen-Assimilating Enzymes in the Chloroplast of Chlamydomonas reinhardtii.

The specific activities of nitrate reductase, nitrite reductase, glutamine synthetase, glutamate synthase, and glutamate dehydrogenase were determined in intact protoplasts and intact chloroplasts from Chlamydomonas reinhardtii. After correction for contamination, the data were used to calculate the portion of each enzyme in the algal chloroplast. The chloroplast of C. reinhardtii contained all enzyme activities for nitrogen assimilation, except nitrate reductase, which could not be detected in this organelle. Glutamate synthase (NADH- and ferredoxin-dependent) and glutamate dehydrogenase were located exclusively in the chloroplast, while for nitrite reductase and glutamine synthetase an extraplastidic activity of about 20 and 60%, respectively, was measured. Cells grown on ammonium, instead of nitrate as nitrogen source, had a higher total cellular activity of the NADH-dependent glutamate synthase (+95%) and glutamate dehydrogenase (+33%) but less activity of glutamine synthetase (-10%). No activity of nitrate reductase could be detected in ammonium-grown cells. The distribution of nitrogen-assimilating enzymes among the chloroplast and the rest of the cell did not differ significantly between nitrate-grown and ammonium-grown cells. Only the plastidic portion of the glutamine synthetase increased to about 80% in cells grown on ammonium (compared to about 40% in cells grown on nitrate).

Journal Article↗
PubMed1988

A Ki-1 (CD30)-positive human cell line (Karpas 299) established from a high-grade non-Hodgkin's lymphoma, showing a 2;5 translocation and rearrangement of the T-cell receptor beta-chain gene.

We describe the characterization of a new human cell line, Karpas 299 (K299), established from blast cells in the peripheral blood of a 25-year-old white man. His illness, which began with enlarged occipital and axillary nodes and weight loss, ended after 7 months with generalized lymphadenopathy, pleural effusion, and bone marrow involvement. A lymph node biopsy showed a large cell lymphoma mainly sinusoidal in distribution. The blast cells with pleomorphic nuclei resembled primitive histiocytes. The cells, which expressed the T-cell-associated markers CD4 and CD5, were positive for HLA-DR, epithelial membrane antigen, and CD30 (Ki-1 antigen). The karyotype was aneuploid and included a translocation 2;5. The site of translocation on chromosome 5 (at 5q35.1) is in the region of the locus of the c-fms oncogene (receptor of the monocyte-macrophage colony-stimulating factor MCSF or CSF-1). The cell line Karpas 299 has the same karyotype and pattern of antigen expression as the patient's cells. Northern blot analysis of RNA showed an active rearrangement of the T-cell receptor beta-chain gene. This is to our knowledge the first Ki-1 antigen-positive line to be established from a case of non-Hodgkin's lymphoma.

Adult↗
PubMed1987

Human T-cell tumours containing chromosome 14 inversion or translocation with breakpoints proximal to immunoglobulin joining regions at 14q32.

T-cell tumours are frequently found to carry an inversion of chromosome 14 (inv(14)) (q11;q32) or more rarely a chromosome 14 translocation t(14;14) with the same cytogenetic breakpoints (q11;q32). We have examined the molecular junctions of an inv(14) and a translocation t(14;14) using T-cell receptor (TCR) alpha joining (J) region probes. Both of these chromosomal abnormalities have breakpoints within the TCR J alpha locus at 14q11 and both have breakpoints which are proximal (i.e. on the centromeric side) to the immunoglobulin heavy chain JH region at 14q32. The cloned segments corresponding to the junctions at 14q32 are not associated with obvious immunoglobulin-like sequences. This contrasts to the previously described inv(14) in the cell line SUP-T1 and places a potential cluster of chromosome 14 breakpoints downstream of the Ig JH locus. The possible role of the varying breakpoints in the development of these tumours is discussed.

Amino Acid Sequence↗
PubMed1987

Accidents in the school environment in Milan, a five year survey.

Data regarding 11,541 cases of school accidents (from kindergarten to senior high school) that required hospital attention for treatment were examined. The information was obtained from the records of the "School Medicine Service of the City of Milan", and covered five school years (from 1980-81 to 1984-85). The surveyed population included over 160,000 subjects for each year. After computer processing, data regarding type of school, year, age of the victim, place of the accident and type of lesions were obtained. The frequency of accidents was highest (about 2%) among kindergarten pupils, while in senior high school the lowest frequency (less than 1%) was accompanied by the greatest percentage of hospitalizations (about 6%). From our results it appears that most accidents occur in school gyms (around 50%), and that the percentage of sprains and fractures is also highest in this area. School gyms can therefore be considered as a primary target for any prevention activity.

Accidents↗
PubMed1987

Amyloid of neurofibrillary tangles of Guamanian parkinsonism-dementia and Alzheimer disease share identical amino acid sequence.

The presence of abundant intraneuronal amyloid in the form of neurofibrillary tangles (NFT) in the brains of Guamanian parkinsonism-dementia patients and the absence of extraneuronal amyloid in the form of vascular amyloid deposits or senile plaques permit the purification of NFT without contamination with extraneuronal amyloid. Thus, we have isolated and determined the amino acid sequence of the polypeptide subunit of the amyloid fibrils of these NFT and describe their ultrastructure. The NFT, which consist of single and paired helical filaments, similar to those of Alzheimer disease, and occasionally triple helical filaments, are composed of multimeric aggregates of a polypeptide of 42 amino acids (A4 protein). The relative molecular mass of the subunit protein, 4.0-4.5 kDa, is the same as the molecular mass of the amyloid of NFT, of the amyloid plaque cores, and of vascular amyloid deposits in Alzheimer disease and Down syndrome; the sequence of 15 amino acid residues at the N-terminus of the amyloid fibrils in the NFT of Guamanian parkinsonism-dementia is identical to that of the amyloid of NFT, amyloid plaque cores, and cerebrovascular deposits in Alzheimer disease and Down syndrome. Furthermore, the heterogeneity, or variation in polypeptide length, of the N-terminus of the amyloid of Guamanian parkinsonism-dementia is the same as in Alzheimer disease and Down syndrome. Our observations indicate that the brain amyloids of these diseases have a common subunit protein, which would also indicate a common pathogenesis.

Aged↗
PubMed1987

Reactions of theophylline, theobromine and caffeine with Fenton's reagent--simulation of hepatic metabolism.

Theophylline and caffeine undergo N-demethylation and hydroxylation by Fenton's reagent to give uric acid derivatives; theophylline is oxidized mainly to 1-methyluric acid, and 1,3-dimethyluric acid and 1-methyluric acid are the major products obtained from caffeine. Theobromine undergoes predominantly N-demethylation to give 7-methylxanthine. The nature of the products indicate that these reactions simulate hepatic drug metabolism.

Caffeine↗