Search PubMed⌕ Search

Biomedical subjects

O Müller

Publications and source records attributed to O Müller.

At least 127 records · Page 7Linked to original sources
PubMed1984

[Deamination and reductive deamination of (2-amino-5, 6-dimethylbenzimidazolyl)cobamide. Preparation of (2-hydroxy-5, 6-dimethylbenzimidazolyl)cobamide and (5, 6-dimethyl-[2(-14)C]-benzimidazolyl)cobamide].

(2-Amino-5, 6-dimethylbenzimidazolyl)-cobamide (III) is transformed to (2-hydroxy-5, 6-dimethylbenzimidazolyl) cobamide (IV) by nitrous acid. Exchange of the NH2-group by hydrogen with nitrous acid/hypophosphorous acid yields vitamin B12 (I). This reaction completes a cycle vitamin B12 (I)----[carboxy(2-cyanoamino-4,5-dimethylphenyl)amino]cobamide+ ++ (II)----(2-amino-5,6-dimethylbenzimidazolyl)cobamide (III)----vitamin B12 (I), which allows chemical 14C-labelling of vitamin B12. In this procedure cyanogen bromide, which is necessary for the first step, was labelled with [14C] cyanide. By the following reactions a vitamin B12 was formed in which C-2 of the 5, 6-dimethylbenzimidazole moiety is labelled.

Chemical Phenomena↗
PubMed1984

16,16-Dimethyl prostaglandin E2 stimulates growth and maturation of rat gastric and small-intestinal mucosa.

In adult rats topical application of 16,16-dm PGE2 (PGE) every 8 h for three weeks led to a dose-dependent increase of the height of the gastric and duodenal mucosa, especially pronounced in the antrum (+115% with the high dose). In the gastric corpus this resulted from an enlargement of the lamina propria and the epithelial cell mass, the latter mainly from a hyperplasia of the surface and foveolar mucous cells. In contrast, the number of parietal cells was not affected. These findings were corroborated by the observation that an increase of antral mucosal height was also induced by a similar parenteral PGE treatment regimen (dosage 25 micrograms/kg). Both longterm intragastric and intraperitoneal PGE treatment led to an increase in DNA synthesis within the mucosa of the gastric antrum and corpus by 19 to 74%. In a third study 25 or 100 micrograms/kg of PGE applied every 8 h intragastrically to 10 suckling rats from the 7th to 11th postnatal day resulted in a dose-dependent increase in the length of the villi and the disaccharidase activities (30-630%). These studies suggest that 16,16-dm PGE2 exhibits a trophic effect on both the stomach and the small bowel.

16,16-Dimethylprostaglandin E2↗
PubMed1984

The quantitation of the rat gastric mucosa by morphometric methods.

Cell and tissue components are three-dimensional objects which are usually studied on thin sections, where they appear as two-dimensional profiles. Stereological methods, which permit an extrapolation from two- to three-dimensional space, are useful to quantify biological structures. After briefly reviewing the fundamental principles of stereology, their practical application as point-, intersection- and particle-counting is explained and illustrated on the gastric mucosa. To facilitate stereologic studies, an analytic model of gastric mucosa is presented. Finally, some data on the quantitative composition of different parts of the rat gastric mucosa as well as the mean volume and number of different gastric epithelial cells are presented.

Animals↗
PubMed1984

Both topical and systemic treatments with 16,16-dimethyl prostaglandin E2 are trophic to rat gastric mucosa.

As shown in a previous study, intragastric administration of 16,16-dimethyl prostaglandin E2 (PGE, 100 micrograms/kg t.i.d.) for three weeks induces growth of the gastric mucosa. The present experiments were designed to study the time course of histological changes after intragastric PGE and to test whether a similar effect could be observed after parenteral administration. Significant thickening of the corpus, but not the antral mucosa was observed after 3 days of intragastric treatment with PGE (100 micrograms/kg t.i.d.), whereas after three weeks the effect was more marked in the antrum than in the corpus. At a dose of 25 micrograms/kg t.i.d., intraperitoneal PGE increased the height of antral mucosa to a similar degree as seen after intragastric treatment. DNA synthesis as assessed by autoradiography after administration of 3H-thymidine at the end of the three week PGE treatment was increased both in the gastric corpus and antrum. Preliminary studies in suckling rats provide evidence that intragastric administration of PGE (100 micrograms/kg t.i.d.) from day 7 to 11 accelerates maturation of the gastric mucosa. It is concluded that thickening of gastric mucosa can be induced by both local and systemic administration of PGE and is due, at least in part, to increased proliferation of gastric mucosal cells.

16,16-Dimethylprostaglandin E2↗
PubMed1983

[Spontaneous radial segmentation of cell nuclei: morphologic marker of T-cell neoplasms?].

Radial segmentation (RS) of leukocyte nuclei has been observed, for example, in leukemias (Rieder cells). In 6 of 8 patients with T-ALL, RS of neoplastic cells was found in the peripheral blood, whereas in 14 patients with non-T-ALL no RS cells were present. RS may be a morphologic marker for certain T-cell neoplasms, and with regard to ultrastructure it seems to be identical to heat-induced RS of non-neoplastic cells.

Cell Nucleus↗
PubMed1983

[Endothelial cell loss after keratoplasty. Specular microscopic observations of immune reactions against donor endothelium].

Seven cases of immune reactions against donor endothelium after penetrating keratoplasty were analyzed in a prospective study. Cell loss during the immune reaction period varied between 25% and 81% and seemed to continue thereafter, though much more slowly. The authors discuss the complex etiology of post-keratoplasty endothelial cell loss and make suggestions for the diagnosis and treatment of classic endothelial immune reactions with special reference to specular microscopy.

Adult↗
PubMed1983

Influence of long-term 16,16-dimethyl prostaglandin E2 treatment on the rat gastrointestinal mucosa.

We performed acid secretory and histomorphometric studies in rats treated intragastrically with a regimen of 100 micrograms/kg or 5 micrograms/kg of 16,16-dimethyl prostaglandin E2, or of saline every 8 h for 21 days. All animals given the high-dose treatment developed a macroscopically visible enlargement of the ridge at the corpus-forestomach border, due to an increase in connective tissue and epithelial cell layer. Mucosal thickness was significantly increased in all parts of the stomach, the duodenum, and the proximal colon, but most markedly in the gastric antrum (+115%), where it was accompanied by a higher mitotic rate and hyperplasia of surface and foveolar mucous cells. Within the oxyntic area (corpus), high-dose prostaglandin treatment led to an increase in the number of surface and foveolar mucous cells and chief cells. In contrast, both the number of parietal cells and maximal acid output were not influenced. It is unlikely that the hyperplasia of gastric mucosa is mediated by gastrin since gastrin has no trophic effects on the rat antrum and disproportionally increases the parietal cell number of the oxyntic gastric glands.

16,16-Dimethylprostaglandin E2↗
PubMed1982

[Fosfomycin concentrations in serum and bile (author's transl)].

40 patients were given a single, short intravenous infusion of 4 g fosfomycin over a period of five to ten minutes. In 23 patients, the contents of the gall bladder were removed intra-operatively 30-105 minutes after the fosfomycin infusion. In 17 patients who had undergone cholecystectomy eight to ten days earlier, bile was obtained via a T-drain 30, 60, 120, 240 and 360 minutes after the fosfomycin infusion. Fosfomycin concentrations of 1-196 mg/l were present in the bile which had been removed intra-operatively. No correlation was found between the concentration and the time of removal. Patients with the highest alkaline phosphatase in serum, however, had the lowest fosfomycin concentrations. In the patients with T-drains, the highest concentrations (93 mg/l) were found 30 minutes after the fosfomycin infusion. By the sixth hour the concentrations had fallen to 19 mg/l.

Adult↗
PubMed1982

Non-contact specular microscopy of the normal corneal endothelium. A statistical evaluation of morphometric parameters.

The corneal endothelium of 179 healthy persons (327 eyes), 4-89 years of age. as photographed through a non-contact specular microscope. From the histograms of the cell areas of each eye, other parameters were derived and subjected to computerized statistical analysis. In addition, photographs of both eyes of one person were taken on two different days and examined to determine the reproducibility of the method. The known age-dependent increase in the mean cell area as well as the decrease of the cell density with age could be confirmed. Other parameters that increase with age are the variability of the mean cell area and the maximum cell area; the latter correlates so well with age and is so easily measured that this parameter may facilitate further morphometric evaluations. For these age-dependent correlations not only regression lines but also third-rank regression curves, which seem to fit better, were calculated. Finally, age-independent parameters were found that may serve as potential additional criteria for a qualitative evaluation of the individual corneal endothelium.

Adolescent↗
PubMed1982

[The corneal endothelium in ophthalmic zoster (author's transl)].

Up till now corneal endothelium changes in ophthalmic zoster have practically escaped general attention. According to our observations, however, a corneal endotheliitis is a regular feature in acute ocular zoster and often occurs as a late complication as well. The authors report on individual controls of the corneal endothelium by means of specular microscopy in six zoster patients who were treated with steroid eye drops.

Cornea↗
PubMed1982

Renal contribution to plasma catecholamines--effect of age.

In 18 subjects undergoing diagnostic cardiac catheterization renal venous noradrenaline during rest (296 +/- 26 ng/l, mean +/- SE) was significantly increased over arterial noradrenaline concentrations (250 +/- 20 ng/l, P less than 0.01) while, in contrast, the arterial adrenaline level (79 +/- 9 ng/l) was higher than the renal venous (41 +/- 4 ng/l, P less than 0.001). Age correlated positively with both renal venous noradrenaline (r = 0.56) and the renal venous-arterial difference of noradrenaline (r = 0.56), and negatively with arterial (r = -0.52) and renal venous adrenaline (r = -0.48). According to our data, a net renal venous secretion of noradrenaline and at the same time an uptake of adrenaline from the renal circulation take place at an extent that may influence plasma concentrations of both. With increasing age renal uptake of plasma adrenaline seems to decrease and net release of noradrenaline to increase. The fall in plasma adrenaline may be due to age-dependent involution of the adrenal medulla. In studies of plasma adrenaline concentrations and of the renal handling of plasma catecholamines the influence of age must be taken into account.

Adolescent↗
PubMed1981

A scanning electron microscopic study of the liver of the monkey Macaca speciosa. I. Vascular system of the hepatic lobule.

The vasculature of the hepatic lobule of the monkey was investigated by scanning and transmission electron microscopy. The vessel walls of the portal and terminal hepatic (central) veins consist of a closed endothelium, a continuous basement membrane and a connective tissue layer. Sinusoids, however, show endothelia with typical fenestrations, and connective tissue fibres are only sparsely distributed in the space of Disse. Kupffer cells are present in the sinusoids, and occasionally in the terminal hepatic and sublobular veins, but are never present in the portal veins. They are characterized by a ruffled surface and special processes--filopodia and lamellipodia--which anchor them to the endothelial cells and also connect them with adjacent Kupffer cells. Flat branches of perisinusoidal cells, which encircle the endothelia, occur in the space of Disse, and are presumed to have a pericyte-like function.

Animals↗
PubMed1980

[Measurement of color-coordinates of the fundus by the color-comparison method with a widened measurement scale (author's transl)].

The method of color measurements by visual comparison was first described in 1974, but the original method was not always adequate in documenting fundal changes in patients being treated with vasodilatators. In these cases the color coordinates reached the threshold of the measuring scale or went beyond it in the livid color area. A few years ago the color measuring instrument was supplied with a new filter system for this purpose and was necessary to move the left cornerpoint of the measuring scale far into the blue range. The instrument and the physical data are described, the standard color values x and y being found by transformational equations. The technical error was measured on a phantom eye. In a defined group of 100 normal eyes (=100 testing persons) the standard color values of the temporal and nasal papillary segments were measured. They are graphically demonstrated in the now widened x; y measuring scale. Clinical use and results will be described later.

Color↗
PubMed1980

[Branch artery occlusion due to focal necrotizing retinitis -- probably caused by toxoplasmosis (author's transl)].

A case of necrotizing retinitis, probably due to toxoplasma gondii, is described in a 21-year-old man. Transient occlusion of the arteriole lying over the lesions was confirmed angiographically. The presence of inflammatory chorioretinal foci in the vicinity of retinal vessels was documented photographically in three other cases. The fundus changes and the field defects in these patients suggested that retinal perfusion had been temporarily impaired. The customary administration of steroids combined with antibiotics appears justified in order to minimise the occurrence of retinal vascular damage in the presence of necrotizing retinitis.

Adolescent↗