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Biomedical subjects

H Pech

Publications and source records attributed to H Pech.

18 recordsLinked to original sources
PubMed1999

Downregulation of endothelin B receptor in human melanoma cell lines parallel to differentiation genes.

Normal human melanocytes have been shown to respond to the signal peptide endothelin by increased proliferation and melanin formation. Contradictory findings, however, have been reported about which of the two endothelin receptors (EDNRA or EDNRB) is expressed in normal melanocytes and melanoma cells. Moreover it was not clear whether malignant cells differ from their normal precursors in this respect. Screening a melanocyte cDNA library for genes downregulated in melanomas identified clones specific for EDNRB. Northern blots proved that the corresponding mRNA is generally expressed in cultures of human cutaneous melanocytes and congenital melanocytic nevus cells. In 16 of 17 melanoma cell lines, however, the expression of EDNRB mRNA was strongly downregulated. EDNRA was only weakly expressed and detectable by northern blotting in 12 of 17 cultures of benign melanocytic cells and four of 17 melanoma cell lines. Nested reverse transcriptase-polymerase chain reaction proved several melanoma cell lines to be completely negative for EDNRA expression. Gene deletion as the cause of missing endothelin receptor expression was ruled out by genomic Southern blots. Receptor binding assays confirmed RNA data revealing 1.6 x 105 endothelin-1 binding sites per cell for a melanocyte culture and between 8.7 x 104 and 400 sites per cell for melanoma cell lines. Expression of pigmentation genes coding for tyrosinase, TRP-1 and TRP-2 correlated positively with that of EDNRB but negatively with EDNRA expression. EDNRB but not EDNRA expression is therefore typical for melanocytic cells, and downregulation of EDNRB seems to be an important characteristic of melanoma cells possibly related to malignancy or apoptosis.

Blotting, Northern↗
PubMed1990

[Enzyme liberation after electrical His bundle ablation].

The release of isoenzymes, i.e. aspartate aminotransferase (ASAT), lactic dehydrogenase (LDH), malic dehydrogenase (MDH), and of creatine kinase (CK) after electric His bundle ablation is presented. The enzyme release is increasing with the amount of energy applied during the intervention. Mitochondrial MDH and ASAT were found in six of the seven patients. Therefore, the size of myocardial necrosis by ablation can be estimated by the sequence of the release of the enzymes, and the isoenzymes, respectively.

Adolescent↗
PubMed1986

Variation and adaptation of Pseudomonas aeruginosa toxicity to HeLa cells and fibroblasts.

The toxic components of supernatants from Pseudomonas aeruginosa cultures directed against HeLa cells and Staphylococcus aureus were evaluated with the aim of discovering interactions. Supernatants of eight different strains of P. aeruginosa were assayed for cytotoxic activity. All were active against HeLa cells; seven were toxic for S. aureus. On repeated suspension of P. aeruginosa in 0.9% sodium chloride solution, a shift from HeLa cell toxicity to staphylococcal lytic activity occurred along with a change of toxic activity from a high (50,000 +/- 5,000) to a low (8,000 +/- 400) molecular weight (MW) range on gel filtration. Addition of protein to the minimal medium of cultures producing material toxic only for S. aureus reactivated the generation of HeLa cell-toxic material. Cultivation of P. aeruginosa in the presence of HeLa cells and a chloramphenicol supplement produced suppression of the generation of material toxic for S. aureus but facilitated that of HeLa-toxic material of high MW. Adaptation of toxicity against fibroblasts developed only on cocultivation of P. aeruginosa together with S. aureus and in the presence of fibroblasts. Under these conditions a strong lytic activity for S. aureus appeared, even in the presence of chloramphenicol. Chloramphenicol caused the material toxic for fibroblasts to elute at a low MW well separated from that toxic for HeLa cells. In contrast to the high-MW toxic substances, the low-MW material did not induce antibodies after injection into rabbits. This may explain failures of vaccination against P. aeruginosa infection and of serum therapy of homologous sepsis in humans.

Bacterial Toxins↗
PubMed1984

Angiotensin II binding to human mononuclear cells: receptor or free fluid endocytosis?

It has recently been claimed that there are angiotensin II (ANG II) receptors on human mononuclear cells and on platelets and this has been used for investigating the regulation of the renin-angiotensin system in hypertension. We here show the following. Binding kinetics of 125I-labelled ANG II and [3H]ANG II to mononuclear cells were slow (maximum at 90 min) and the same as for [3H]-inulin. As with [3H]inulin there was no binding at 4 degrees C. Release from the cells was slow and incomplete (about 30% after 15 min, 60% after 60 min). Binding was not saturable over a range from 10(-12) to 10(-6) mol of ANG II/l, about 8% of offered peptide being bound at all concentrations. Various inhibitors of free fluid endocytosis exhibited the same inhibition pattern of ANG II binding to mononuclear cells. Therefore uptake of ANG II into mononuclear cells displayed all the features of free fluid endocytosis. ANG II was degraded by carboxypeptidase A. When this degradation was prevented by D-phenylalanine, no binding occurred. In platelet preparations contaminated by 0.3-5% of mononuclear cells, 125I-labelled ANG II was degraded as well. Free fluid endocytosis of the degradation product strongly depended on the percentage of contaminating mononuclear cells. We conclude that there are no ANG II receptors on human mononuclear cells and that their presence on human platelets is doubtful.

Angiotensin II↗
PubMed1978

[Nutritional status and health status of under-fives of the Mentawai island Sipora (Indonesia) (author's transl)].

Weight, Height, head circumference, chest circumference, arm circumference and triceps skinfold of 223 children under 5 years from the small Mentawai island Sipora/Indonesia have been measured and related to international standards. Beginning from standard values, the anthropometric data decrease during the first 2-3 years, rising again in the following years. Weight for age is 72% of standard at 24 months and 83% at 5 years, height for age 89% at 30 months and 92% at 5 years, weight for height of the boys 82% at 12 months, of the girls 79% at 24 months and 94% for both at 4-5 years, chest/head ratio 95% at 12 months and 100% at 3-5 years. Arm circumference is 83% at 18 months 100% and above already at 3 years. Therefore, fold regains after the minimum of 90% at 18 months and above already at 3 years. Therefore, muscle growth would predominantly be reduced. The weight gain follows approximately the 3rd centile of english girls with a clear depression between 9 and 30 months. The birth weights of 476 children are 3230 g (boys) and 3120 g (girls). Perinatal mortality is low (2.9%), mortality during the first 5 years between 15 and 24%. In the health centre charts of 126 children under 5 years of a selected village (93% of that age group) 463 treatments in 5 years are recorded. The most frequent diagnoses are diseases of the respiratory tract (38% of all treatments), followed by malaria (23%), diarrhoea (19%), ascaris and hookworm infections (7.6%) and skin conditions (6%). Tuberculosis was the cause of treatment in 1.3%. In spite of the temporary growth retardation, as indicated by the anthropometric values, no cases of clinical Protein-Energy-Malnutrition have been observed. Malaria seems to be holoendemic, since all 223 children had a palpable spleen.

Anthropometry↗
PubMed1976

[Release by agitation of constituents from cell walls of Pseudomonas aeruginosa. III. Communication: Electron microscopy (author's transl)].

A thermovariable inhibition of agglutination (EA) was demonstrated in two randomly chosen strains of Pseudomonas aeruginosa (table 1, article I). The temperature range from the loss of agglutinability to its recovery was as described in previous articles (II). The agglutination patterns were similar to those of the O-group-type strains 1 and 4, indicating that the IA is a widespread property among Pseudomonas aeruginosa strains. Shaking at moderate intensities for 20-60 hours restored the thermosensitive agglutinability (Table 2, article I), and the times necessary for restoration were somewhate dependent on the specific culture media and the strains used (table3, article I). After restoration of agglutinability the bacteria had maintained their capability to form stable suspensions in physiological saline solution (table 2, article I). Another treatment at elevated temperature did not result in an IA (table 5c, article I). During the shaking the pelleted bacteria did no longer exhibit their normal slimy stickiness, similar to what has been observed after treatment with hyaluronidase (17). When the shaking was continued after restoration of agglutinability a special serological phenomenon ("Rauh-Phänomen," cf. table 5b in article I) was noted. Suspension of the bacteria in physiological saline for 7 days did not result in the recovery from the thermovariable IA (table 4, article 1). The secondary forms of the agglutinates were similar to those of Enterobacteriaceae, the typical primary form of the agglutination into slimy networks and spheres was not observed upon the restoration of agglutinability. The hypothesis that loosely bound surface components are responsible for the thermovariable IA was examined by chemical analyses of the fractionated supernatants obtained during the shaking treatments. The first supernatant fractions obtained after relatively brief shaking periods exhibited a high viscosity, in contrast to the low viscosity of supernatants harvested later. Total acetone-precipitable material from the supernatants contained lipids, proteins and carbohydrates, however, at different ratios (tables 1, 2, 3, article II). The amounts of lipids recovered from the supernatants were similar in all fractions during the shaking treatment, whereas protein-carbohydrate complex material was maximal in the first fractions and significantly decreased in fractions harvested later (table 1 and 2, article II). The data indicated, that the restored agglutinability at elevated temperatures and the maintained suspensibility in physiological saline was due to the removal of a limited amount of material from the most superficial layer of the bacterial wall; however in the continuous presence of the cell membrane and perhaps also of the internal cell wall layers (see also 8). This concept was examined by electron microscopy. The morphology of the native bacteria is illustrated in figures 1-3 (article III)...

Agglutination↗
PubMed1975

[Hemodynamics of the left ventricle during myocardial infarct].

It is issued from the fact that in acute myocardial infarction depending on expansion and localisation of the necrosis, on the degree of the possible functional adaptation of the not-affected myocardium or its previous injury must be reckoned with different changes of the haemodynamics. The sufficient judgment of the function of the left ventricle which is necessary for a differentiated therapy is possible only by the combination of several haemodynamic parameters. First results of direct measurements of pressure and volume of the left ventricle in patients with acute myocardial infarctions are demonstrated. Two types of haemodynamic constellation and their therapeutic influence are demonstrated. By the provable applanation of the functional curve of the left ventricle a change of the optimum working points develops; a secure differentiation between the reduction of the contractile function and reduced diastolic distensibility, however, is not only given on account of the displacement of the functional curve of the left ventricle. The results show that for a haemodynamic monitoring apart from the direct or indirect determination of the filling pressure of the left ventricle a practicable measurement of the cardiac output which must be repeated several times is necessary for an aimed therapy from haemodynamic aspects.

Blood Pressure↗