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Biomedical subjects

H Meister

Publications and source records attributed to H Meister.

At least 37 records · Page 2Linked to original sources
PubMed1990

Experimental pancytopenia of the peripheral blood with granulocytopoietic bone marrow hyperplasia in the beagle-dog.

During subacute and chronic toxicity studies on beagle dogs with the platelet aggregation inhibitor UH-A 46 XX, a suboxicam derivative, a pancytopenia of the peripheral blood with granulocytopoietic bone marrow hyperplasia was induced. Our observations are based on the results of a 13 week routine experiment (control group and dosage groups 5-, 50- and 700 mg/kg per day UH-A 46 XX) and on a special open-ended reversibility study (control group and dosage groups 50- and 700 mg/kg). The reversibility study included closely monitored hematological controls, bone-marrow cytology from sternal punctures and plastic section histology of iliac crest biopsies. During this study, plasma levels of the substance were estimated. The reproducible syndrome described was similar in the dogs in both studies. As early as the 8th week, but mostly between the 9th and 12th experimental weeks, one third of the animals treated orally with 700 mg/kg b.wt. UH-A 46 XX per day developed an acute fever (10 out of 30 animals). Four died several days later. Dogs treated with 5 or 50 mg/kg UH-A 46 XX remained unaffected. In the diseased dogs in both studies, proven pancytopenia was associated with the occurrence of numerous hematopoietic, especially granulocytopoietic precursors. The hyperplastic bone marrow showed a massive increase in granulocytopoiesis with considerable maturation arrest. These processes were accompanied by suppression or reduction of erythropoiesis. In addition, histological findings in the animals that died showed extramedullary hematopoiesis in different organs. During the second study, the reversibility was investigated in sick animals. If substance administration was terminated when the illness had reached its peak, normalization occurred quickly within 2 to 3 weeks. The animals remained healthy until the end of the long term follow-up which varied from 9 to 10 months. The pathogenesis of pancytopenia caused by UH-A 46 XX seems to be a chemically induced hyperdestruction of the peripheral blood cells. This appraisal is supported by the clear degenerative alterations in the granulocytic cells of the peripheral blood. An additional inhibitory effect of UH-A 46 XX on cellular maturation processes of hematopoiesis can be assumed.

Administration, Oral↗
PubMed1985

Membrane topology of light-harvesting protein B870-alpha of Rhodospirillum rubrum G-9+. Amino acid residues in contact with the lipid bilayer as inferred from labeling with photogenerated carbenes.

The amino acid residues of the light-harvesting protein B870-alpha of Rhodospirillum rubrum G-9+ that in the chromatophore membranes are in contact with the lipid phase were identified by hydrophobic photolabeling. Three reagents have been used which all contained the trifluoromethyldiazirinylphenyl group as a photo-sensitive precursor of a carbene but which otherwise differed in shape, molecular structure, and in the way they interact with membranes. 3-Trifluoromethyl-3-(m-[125I]iodophenyl)diazirine is a highly lipid-soluble compound, 11-[4-[(trifluoromethyl)diazirinyl]-phenyl]-[10-3H] 9-oxaundecanoic acid is an analogue of a fatty acid, and 1-palmitoyl-2-[11-[(trifluoromethyl)diaziri-nyl] phenyl]-[10-3H]9-oxaundecanoyl]-sn-glycero-3-phosphorylcholine one of a lecithin. Following labeling of chromatophores with these reagents, B870-alpha was isolated and subjected to (solid phase) Edman degradations in order to determine individual amino acid residues labeled. The main features of these results are as follows. 1) Labeling occurred both within the N-terminal segment (residues 1-8) and within the predominantly hydrophobic transmembrane stretch (residues 14-33). 2) Label distribution patterns within segments are indicative of helical structures to which the reagents had access to one face only of the cylindrical envelopes. 3) With regard to the transmembrane segment, the label distribution patterns were similar for all reagents whereas striking differences were noticed within the N-terminal portion. The labeling patterns are consistent with previous models proposing tight association of the transmembrane helix with that of the B870-beta chain. They also suggest that the N-terminal segment forms an amphipathic helix which interacts with the water-lipid interface of the membrane.

Affinity Labels↗
PubMed1985

[The capacity and limits of laboratory diagnosis].

From observations of the daily cooperation between clinic and out-patient department and laboratory, respectively, result several basic and critical considerations. It is tried to analyse the causes of certain developmental tendencies which by the two sides are regarded as disturbing and unfavourable and to draw conclusion for the sake of a reasonable use of the laboratory capacities and a good cooperation between the partners.

Blood Chemical Analysis↗
PubMed1984

[Prognosis disclosure to the dying patient].

Different, partly contrary opinions exist as to the difficult and important problem, how far the physician may or must go in informing the patient and his nearest relatives about an infaust prognosis. The author makes his own position which was under consideration in the working team "Ethical Problems" of the GDR Society of Internal Medicine subject of a discussion.

Attitude to Death↗
PubMed1984

2-[8-14C]naphthyl 2-diazo-3,3,3-trifluoropropionate, a new carbene generating reagent for probing hydrophobic membrane domains.

A new precursor of a lipophilic photolabel, 2-[8-14C]naphthyl 2-diazo-3,3,3-trifluoropropionate (NADIT) has been synthesized. The suitability of the reagent for labeling the hydrophobic core of membranes is demonstrated by studying its reactivity in chromatophores of Rhodospirillum rubrum G-9+. The label binds preferentially to the phospholipids and intrinsic membrane proteins. In isolated reaction centers treated with NADIT the hydrophobic subunits M and L are more labeled than the H subunit. The high reactivity, dark stability and ease of synthesis favors this very lipophilic reagent to identify the intrinsic hydrophobic sections of membrane proteins.

Affinity Labels↗
PubMed1982

[Carditis as a rare complication of ulcerative colitis].

It is reported on a 24-year-old patient with ulcerous colitis, in whom a severe peri-myocarditis appeared two weeks of the beginning of an acute episode. With reference to reports of analogous courses in literature a causal connection with the basic disease is discussed and this is put aside the essentially more frequent and more notorious secondary diseases of ulcerous colitis (arthritides, changes of skin, eyes and liver).

Adult↗
PubMed1982

[Animal experiments to assess the risk of cancer in the stomach after vagotomy (author's transl)].

To assess the possible risk of cancer in the operated stomach, the influence of truncal vagotomy combined with different operative drainage procedures (pyloroplasty, gastro-enterostomy without entero-anastomosis, Roux-en-Y gastro-enterostomy) was studied in animal experiments. The aim of the study was to determine whether, compared to controls an earlier and higher incidence of precancerous epithelial lesions or cancers in the stomach occurs in vagotomized animals after oral administration of carcinogens (MNNG). To consider conditions, that may predispose to in vivo formation of carcinogenic N-nitroso compounds, bacterial flora and intragastric nitrite concentration were measured and compared in the various operative groups. The severity of induced epithelial lesions and the quantity of bacterial growth and nitrite concentration in the gastric juice were influenced, apart from the reduction of acid output after vagotomy, mainly by prolonged gastric stasis or the degree of enterogastric reflux. The results suggest that there is probably no increased risk of cancer following vagotomy, if sufficient gastric clearance is guaranteed and enterogastric reflux is largely excluded.

Animals↗
PubMed1981

Frequency of cancerous and precancerous epithelial lesions in the stomach in different models for enterogastric reflux.

A gastroenterostomy without entero-anastomosis in rats favours the development of adenomatous epithelial lesions at the gastroenteral borderline in dependence of exposition to MNNG. The extent of such changes in the mucosa could be modified by vagotomy, pyloroplasty, or the prevention of duodenogastric reflux (Roux-en-Y method), whereby vagotomy has an enhancing effect on proliferation. A comparison of the mucosal changes at the gastroenteral anastomosis indicates that a multitude of factors causes environmental changes at the gastroenteral borderline, stimulating epithelial proliferation to the point of cancer formation. Thus, it is not possible to accuse any single factor such as intestinal reflux, carcinogens or different surgical techniques as the sole culprit in carcinogenesis.

Animals↗
PubMed1981

[Surgical aspects of early stomach cancer].

The diagnosis of early gastric cancer can be preoperatively suspected, but can be made only by careful histological study of the resection material. In suspicion of early gastric cancer by X-ray or endoscopy the operative procedure cannot be simplified systematically, but the rules of cancer surgery require full observance. The extent of stomach resection will depend on tumor localization, macroscopic tumor appearance and the knowledge of the histological tumor type. Multicentricity and the continuous tumor growth, especially in diffuse type gastric cancer, and possible lymph node metastases must be taken into consideration in the surgical management. Despite differences in survival rates between various histological types of early gastric cancer the prognosis of the patients is highly favourable, given to adequate therapy.

Biopsy↗
PubMed1979

[Prognostic aspects of early gastric carcinoma (author's transl)].

The results of treatment of early gastric carcinoma were analysed in 65 patients. In 33 patients the operation was performed 5 years ago. The 5-year-survival rate was 70%. Prognosis was predominantly influenced by the histology of the tumour. Signet ring cell and anaplastic early carcinomas (diffuse type) had a worse prognosis than intestinal (differentiated) forms. Carcinomas localised wholly in the mucosa had no better prognosis than those penetrating into the submucosa. There is no choice of surgical method according to prognostic criteria as the diagnosis "early gastric carcinoma" can be made only postoperatively from the resection material. Bioptic proof of carcinomatous gastric mucosal changes requires full observation of the rules of cancer surgery.

Biopsy↗
PubMed1979

Gastritis, intestinal metaplasia and dysplasia versus benign ulcer in stomach and duodenum and gastric carcinoma -- a histotopographical study.

In histological examination of gastrectomy specimens from patients with duodenal ulcer, gastric ulcer, and early and advanced cancer, both chronic atrophic gastritis and intestinal metaplasia were identified in 54% of the cases with duodenal ulcer. At 90 to 100%, respectively, these mucosal changes were approximately twice as frequent with gastric ulcer and early and advanced gastric cancer. Mild dysplasia occurred in 54% of the cases with duodenal ulcer; occurred somewhat more frequently with gastric ulcer, in 75% of the cases; and in almost all cases with early and advanced gastric cancer, at 90% and 100%, respectively. Whereas 27% of the cases with duodenal ulcer, 62% with gastric ulcer, and 90% and 95% of the respective cases with early and advanced gastric cancer showed moderate dysplasia, only severe dysplasia in early gastric cancer (40%) and advanced gastric (81%) was clearly more frequent in comparison to duodenal ulcer (9%) and gastric ulcer (12%). In the cases with duodenal ulcer chronic atrophic gastritis and intestinal metaplasia were limited mostly to the antrum; with gastric ulcer and cancerous stomach disorders, they also occurred in other stomach sections. Mild and moderate dysplasia conformed to the same distribution pattern. Severe dysplasia, which was only detected in two ulcer cases, was not only substantially more frequent in cases with early and advanced gastric cancer, but also showed a clear topographic relationship to cancer localization in the stomach.

Aged↗
PubMed1979

[Effects of ventilation with defined formaldehyde concentrations on lung function and lung structures. Animal experiments on the noxiousness of formaldehyde residues after disinfection in the aseptor (author's transl)].

Having seen the development of fatal pneumonias in ventilated patients, the cause of which was assumed to be the presence of residual traces of formaldehyde in the air in the respirator Kilian and Haug showed in 1973 initial formaldehyde concentrations up to 0.2 ppm in the ventilatory air of respirators correctly disinfected in the Aseptor. To study the effects of formaldehyde on lung function and lung structures, 23 young pigs were automatically ventilated with defined formaldehyde concentrations during 6 hours. The concentrations used were 0.02 ppm, 0.2 ppm and 2.0 ppm (double of the maximum permissible concentration). We found no differences in lung function, as shown by compliance measurements and arterial blood gas analysis. No radiological differences were in the thorax. Histologically, there were only slight alterations in lung structure in the group ventilated with double the maximum permissible concentration of formaldehyde. We conclude that the disinfection of respirators using formaldehyde in the Aseptor will remain the method of choice.

Animals↗
PubMed1979

Dysplasia of the lymphatics with lymphoedema, generalized lymphangiectasis, chylothorax and "pseudo-storage-disease".

A patient showing an unusual association of various abnormalities of the lymphatic vascular system is reported. These abnormalities became first evident in early childhood and consisted of lymphoedema of the left leg, lymphangiectasis in various organs and occlusion of the thoracic duct at its entrance into the venous angle. Chylous effusions and subcutaneous chyloedema appeared in adolescence. Diagnostic biopsies of spleen, liver and bone-marrow revealed the presence of multiple foamcells, suggesting the diagnoses of lipid storage disease. The patient died from severe honeycomb-lungs at the age of 20. This case cannot be attributed to one of the wellknown disease entities of the lymphatic system. The "pseudo"-storage disease is regarded as secondary to the backflow of chylus into the tissues.

Adolescent↗
PubMed1978

[Diagnostic and therapeutic aspects of early (superficial) gastric carcinoma: a retrospective analysis of 60 cases (author's transl)].

Among 947 patients operated on for gastric carcinoma between 1961 and 1976 there were 60 with early (superficial) gastric carcinoma. All but two patients consulted their doctor for diverse complaints. In one third of them treatment was delayed for a year or longer. In 26 of the 64 cancer foci it was limited to the mucosa. The correct diagnosis was made radiologically in 60%, gastroscopically in 70%. Selective endoscopic biopsy increased accuracy to 90%. The remaining false-negative findings occurred in the ulcerative form, which was the most frequent one. Improved radiological techniques (double-contrast) and obligatory gastroscopy with biopsy increased the relative proportion of early (superficial) carcinoma from under 4% in 1961 to 15%. The diagnosis of this type of carcinoma can be made only by careful histological study of the surgical specimens. Here as elsewhere in the surgery of carcinoma, multicentricity (in 5%) and possible lymph node metastases (10-20%) must be taken consideration in the surgical management.

Adult↗
PubMed1977

[Influence of duodenal reflux on the epithelium of the gastroenteral anastomosis (author's transl)].

The cancerogenic effect of continous duodenal reflux on the gastric mucosa has been investigated in male Wistar-rats after gastrointestinal anastomosis. Groups of animals with gastroenterostomy without enteroenteral anastomosis and with Roux-en-y-anastomosis preventing duodenal reflux were treated with lower dosages of the cancerogenic Nitrosoguanidine. Proliferative mucosal alterations near the gastroenteral anastomosis were observed. In addition the gastric mucosa was characterized by adenomatous lesions caused by duodenal reflux. The changes detected were not influenced by Nitrosoguanidine and did not appear in cases of Roux-en-y-anastomosis.

Adenoma↗