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Biomedical subjects

H Peters

Publications and source records attributed to H Peters.

At least 163 records · Page 9Linked to original sources
PubMed1983

Charge-related alterations of the cerebral endothelium.

In a short-term rat brain perfusion model, the luminal surface of cerebral endothelium was exposed to the following solutions: (a) the polycation protamine sulfate (PS) in a dose of 50, 100, and 500 micrograms/ml for 1 or 2 minutes; (b) PS in a dose of 100 micrograms/ml (or 500 micrograms/ml) for 1 or 2 minutes followed by the polyanion heparin in an equivalent dose of 12 units/ml (or 60 units/ml) for 1 or 2 minutes; (c) heparin alone for 1 or 2 minutes, and (d) Krebs-Ringer-bicarbonate solution as control for 1, 2, or 4 minutes. We studied in the cerebral endothelium: (a) structural alterations by electron microscopy, (b) permeability changes to horseradish peroxidase (HRP) by light and electron microscopy, and (c) charge alterations of luminal surface visualized with colloidal iron at pH 1.8 by electron microscopy. We found that: (a) PS resulted in extravasation of HRP throughout the perfused hemispheres in a time- and dose-dependent fashion. In this experimental group, colloidal iron binding decreased on the luminal surface of the cerebral blood vessels; (b) heparin perfusion following PS reversed the colloidal iron staining but failed to prevent the blood barrier opening to HRP; (c) heparin perfused alone also induced extravasation of HRP in the treated brain hemispheres; (d) in Krebs-Ringer-bicarbonate-perfused control brains extravasation of HRP was encountered only in occasional vascular segments. In all brain hemispheres showing tracer extravasation, electron microscopy revealed HRP reaction product in compartments of endothelial tight junctions suggesting opening of interendothelial routes as the structural basis of blood-brain barrier opening. Endothelial cell death reflected by swelling and influx of HRP into endothelial cytoplasm in PS- and/or heparin-perfused hemispheres was probably an additional mechanism explaining tracer extravasation into the neuropil. Our results indicate a correlation between the effect of polycation PS and a decrease in the anionic sites of cerebral endothelium. The relationship between charge alteration and barrier opening in the short-term rat brain perfusion model is not clear.

Animals↗
PubMed1983

Abnormal growth of ovarian antral follicles in breast cancer patients.

Ovarian antral follicles from patients with breast cancer were compared with follicles from healthy women. Steroid levels in the follicular fluid and the health status of the follicles were evaluated. Follicles were judged to be healthy or atretic by flow cytometric determinations of the deoxyribonucleic acid content of aspirated granulosa cell nuclei. Fifteen of the 25 follicles (60%) from the cancer patients contained unmeasurable or abnormally low steriod levels (i.e., less than 100 ng/ml) which were significantly (P less than 0.001) lower than in follicles of the same health status from healthy women (500 to 1000 ng/ml). It is speculated whether substances other than the usual follicular steriods are produced by the cancer patients, which stimulate mitotic activity of the granulosa cells.

Adult↗
PubMed1982

Enzyme-linked immunosorbent assay for detection of T-2 toxin.

A microtest plate enzyme immunoassay has been developed for the detection of T-2 toxin. Haptenic T-2 hemisuccinate was immobilized on polystyrene surfaces coated with poly(D-lysine). rabbit antisera against T-2 toxin were added. The binding of the first antibody was detected by addition of an anti-rabbit-immunoglobulin/peroxidase conjugate. After conversion of the substrate 2,2'-azinobis(3-ethyl-2,3-dihydrobenzothiazole-6-sulfonate)/H2O2, the absorbance at 414 nm was monitored. Presence of free T-2 toxin during the first incubation step led to a concentration-dependent lowering of absorbance. The lower detection limit was at about 2 pg per assay. The cross reactivity of T-2 toxin antiserum with other trichothecenes, as determined by ELISA, is weaker than that reported by other authors using a radio-immunoassay technique.

Animals↗
PubMed1982

[High-calorie parenteral nutrition with a complete solution in the postoperative phase].

An investigation of the efficacy of a new developed solution for total parenteral nutrition with high substrate concentrations (3.5% amino acids, 21% carbohydrates as glucose and glucose substitutes, electrolytes) is presented. The solution was tested in 18 patients with major abdominal, thoracic or vascular surgery. The nutritional effect of the maintenance solution is shown to be good. There were no special or systemic side effects. Except for potassium remarkable corrections for the electrolyte requirements were not necessary.

Adult↗
PubMed1982

Differentiation of C3b receptors on human lymphocytes, phagocytes, erythrocytes and renal glomerulus cells by monoclonal antibodies.

C3b receptor protein was purified form human erythrocytes by 2 M KBr solubilization and affinity chromatography on C3-coated sepharose. This material served as antigen for raising monoclonal antibodies. To investigate the distribution and antigenetic relationship between the receptors for C3b on human erythrocytes, lymphoid and phagocytic cells, as well as kidney cells three monoclonal antibodies were selected which inhibited the binding of EAC14 degrees 23b to complement receptor-bearing cells. This could be shown for human erythrocytes by inhibiting the immune adherence reaction, for tonsil lymphocytes, Raji cells, and guinea-pig spleen cells by inhibition of rosette formation of these cells with EAC14 degrees 23b, and for human renal glomeruli by blocking of the the adherence of EAC14 degrees 23b to kidney sections. In contrast, these monoclonal antibodies were not capable of inhibiting rosette formation of human granulocytes and monocytes with EAC14 degrees 23b. The antibodies only interfered with the rosette formation, of EAC14 degrees 23bi and EAC14 degrees 23d with Raji cells and tonsil lymphocytes-if at all-at high concentrations, whereas the rosette formation of Raji cells and tonsil lymphocytes with EAC14 degrees 23b was influenced by supernatants of the selected clones up to a dilution of 1:10(3) to 1:10(5).

Animals↗
PubMed1982

[Yersinia enterocolitica infection. On the differential diagnosis of acute lower right-sided abdominal pain].

Yersinia enterocolitica is a pathogenic organism, hitherto being of minor clinical interest only. In all unclear abdominal complaints especially in the right middle or lower part of the abdomen a Yersinia enterocolitica infection should also be taken into consideration.--Specific diagnostic measures have to be taken and in a suspected case antibiotics should be administered.--In every case an appendectomy has to be performed and a lymphnode should be extirpated and sent for histologic and microbiological examination.

Acute Disease↗
PubMed1981

Endothelial surface charge: blood-brain barrier opening to horseradish peroxidase induced by the polycation protamin sulfate.

Perfusion of rat brain with the polycation protamin sulfate caused a decrease in the stainability of luminal surface of cerebral endothelium to positively charged colloidal iron. This change reflecting a decrease in the anionic sites of the endothelial plasma membrane was accompanied by opening of the blood-brain barrier to horseradish peroxidase. The polyanion heparin reversed colloidal iron binding but failed to prevent permeability alteration of the cerebral endothelium.

Animals↗
PubMed1980

Automobile inspection and maintenance programs: their role in reducing air pollution.

The development of Inspection and Maintenance Programs to control automobile emissions are one component of a comprehensive strategy to reduce automobile related air pollutants such as CO, NOX, and HC. Since the efficiency at which most motored vehicles are designed to limit pollutant emissions deteriorate with prolonged driving, an Inspection and Maintenance system is needed to restore the ability of the automobile to achieve its designed emission standards. Several types of approaches toward developing Inspection and Maintenance Programs in the U.S. including city, county, and state levels of organization and their effectiveness have been described. However, information on the efficiency of these approaches in achieving reductions in pollutant levels remain to be documented, as well as the cost effectiveness of such programs, and their acceptance by the public. In light of the important role that Inspection and Maintenance Programs have been projected to have in the U.S. in reducing automobile related air pollution, it is recommended that interdisciplinary research projects evaluating the multiple dimensions of Inspection and Maintenance Programs be initiated.

Air Pollution↗