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Biomedical subjects

O M Müller

Publications and source records attributed to O M Müller.

9 recordsLinked to original sources
PubMed1990

Lateral thermal damage along pulsed laser incisions.

The damage adjacent to incisions created in dorsal mouse skin by overlapping Er3+ and CO2 laser pulses of a duration of 250 microseconds is investigated histologically. It is compared to injuries induced by long-term heating. We demonstrate how the lateral thermal damage near the laser cuts can be explained by heat conduction. We show that it is necessary to introduce as a heat reservoir a layer of tissue that has been liquified during the cutting process. The width of the thermally damaged region depends mainly on the extension of the liquid material that remains in the cut after the laser-tissue interaction.

Animals↗
PubMed1987

Effect of 16,16-dimethyl prostaglandin E2 on small intestinal mucosa in suckling rats.

Suckling rats were treated every 8 h by intragastric instillation of 16,16-dimethyl prostaglandin E2 (PG) in a dose of 25 micrograms kg-1 (PG25), or 100 micrograms kg-1 (PG100), or saline from postnatal day 7-11. PG increased small intestinal villus length and crypt depth, most markedly in the duodenum, leading to a mucosal height of 543 +/- 24 microns after saline, 670 +/- 26 microns after PG25 and 823 +/- 40 microns after PG100. In the proximal small bowel, PG100 raised the mean activities of sucrase by 439%, maltase by 98%, trehalase by 584%, lactase by 58% and alkaline phosphatase by 76%. In the distal small intestine, only sucrase and trehalase activities were stimulated whereas other enzymes were depressed. PG25 caused similar but less pronounced changes of enzyme activities. Eight hours after both the last PG25 and the last PG100 dose, plasma gastrin and corticosterone levels were decreased while thyroxine remained unchanged. The effect of a single dose of 100 micrograms kg-1 PG or saline was also tested on 5- and 11-day-old rats; they were killed 16 h after PG administration. An increase in villus length occurred along the entire small intestine of rats treated on day 5, and also in the ileum of rats treated on day 11. In the proximal intestine, maltase and trehalase were stimulated after early and late treatment and, in addition, sucrase and lactase after late treatment. Serum corticosterone levels were found to be significantly higher 2-6 h after PG100 than in the controls and then decreased gradually.(ABSTRACT TRUNCATED AT 250 WORDS)

16,16-Dimethylprostaglandin E2↗
PubMed1986

Structure and function of gastric corpus mucosa in suckling rats after treatment with 16,16-dimethyl prostaglandin E2.

Suckling rats were treated every 8 h by intragastric instillation of 16,16-dimethyl prostaglandin E2 (PG) from postnatal day 7 to 11. As compared to saline control treatment, PG increased the thickness of antral and corpus mucosa, the volume density of parietal cells, the mean individual parietal cell volume and pentagastrin-stimulated acid secretion at the end of the treatment. Plasma gastrin and corticosterone levels were depressed by PG while plasma thyroxine levels were unchanged. These structural and functional changes suggest PG-induced accelerated maturation of gastric mucosa.

16,16-Dimethylprostaglandin E2↗
PubMed1985

Circadian changes of the rat pancreas acinar cell. A quantitative morphological investigation.

The dynamics of the physiologic secretory cycle of the rat pancreatic acinar cells along a 24-h span with an alternating 12 : 12 light to dark cycle have been quantitated by morphometric methods. Significant circadian changes could be detected in cell volume and the volumes and surface areas of secretory granules and several organelles involved in the secretory process. During the dark period, which is the activity and feeding period, there is a decrease in the size of cells and individual zymogen granules as well as in the amount of secretory material. This is paralleled by a drop in the number of ribosomes and Golgi vesicles (after a transient increase) and a loss of cytoplasmic membranes. Most of the cell's zymogen content is refilled during the first hours of the light period, when cellular autophagy reaches maximal values.

Animals↗
PubMed1983

Radial segmentation of nuclei (Rieder cells): a morphological marker of T-cell neoplasms?

Pretreatment blood smears of adult patients with acute lymphoblastic leukemia were examined for neoplastic cells showing nuclear radial segmentation (RS). RS was present in 6 of 7 patients with immunologically proven T-cell leukemia, but not in 11 patients whose leukemic cells lacked T-cell markers. Electron microscopic studies of neoplastic cells showed multiple nuclear indentations and abundant cytoplasmic microfilaments and microtubuli in connection with pericentriolar dense material. RS formation was decreased in 1 patient after chemotherapy with a vincristine-containing regimen, while the white cell count remained unchanged. Radial segmentation (RS) of leukocyte nuclei is a well-known phenomenon, which is observed ex vivo (Rieder cells), and can be induced in vitro. Convoluted or multilobulated nuclei in lymphoid neoplasms are similar to RS nuclei both with regard to their structure and their sensitivity to spindle-blocking drugs. We propose that the nuclear alterations observed in a variety of different T-cell neoplasms are identical with RS, and suggest that RS might be a morphological marker for subsets of lymphoproliferative disorders of T-cell origin.

Adult↗
PubMed1981

Heat-induced radial segmentation of leucocyte nuclei: a non-specific phenomenon accompanying inflammatory and necrotizing diseases.

Heat-induced radial segmentation (RS) of leucocyte nuclei in vitro (2 h at 41 degrees C) is a heretofore unknown phenomenon, accompanying inflammatory and necrotizing diseases. This phenomenon appears to be identical with the known oxalate-induced radial segmentation and is caused by contractile microfilaments and microtubuli radiating from the centriole. Preincubation of washed leucocytes from healthy donors with plasma of patients showing the phenomenon of RS did not induce RS and preincubation of washed RS-leucocytes with normal plasma did not suppress RS. RS, however, could be induced by intravenous endotoxin injection in a healthy volunteer and could be prevented in part by addition of Vincristine to the blood samples. The phenomenon corresponds to an incomplete, heat-inducible amitosis. The cause of the thermolability of the mitotic apparatus in various diseases remains unclear.

Bacterial Infections↗