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Biomedical subjects

P Fritsch

Publications and source records attributed to P Fritsch.

At least 253 records · Page 14Linked to original sources
PubMed1976

Staphylococcal toxic epidermal necrolysis: species and tissue susceptibility and resistance.

The staphylococcal exfoliatin, which is responsible for the "scalded skin syndrome" in man, cleaves the epidermis directly beneath the stratum granulosum. Its activity in vivo is paralleled in organ cultures, providing a rapid and convenient assay. The cutaneous responses of several mammalian and nonmammalian species were examined both in vivo and in vitro. Human and murine skin, as well as that of hamsters and monkeys exfoliated, while all other species tested (rat, rabbit, guinea pig, dog, frog, and chicken) were refractory. Results were identical in vivo and in vitro. Susceptibility and resistance are inherent, presumably genetic, attributes of the epidermis, since neither dermal elements nor circulating factors interfered with or influenced sensitivity to staphylococcal exfoliatin. Besides possessing species specificity, this exfoliatin is also tissue specific, failing to cleave all mouse nonkeratinizing epithelia tested, while the reactions of some extracutaneous keratinizing epithelia were equivocal. The species and tissue specificity of the staphylococcal scalded-skin syndrome may be attributable to either keratinocyte receptors specific for exfoliatin or the presence of specific, as yet undefined, substances in the intercellular space.

Animals↗
PubMed1976

Melanocyte-stimulating hormone receptors on cultured guinea-pig melanocytes.

Guinea-pig melanocytes in mixed epidermal cell cultures bind melanocyte-stimulating hormone in a distinct focal surface area in their perinuclear field and thus follow the same pattern previously described for Cloudman melanoma cells. The labeling index ranged from 18 to 34%. Pretreatment of cultures with trypsin leads to destruction of melanocyte-stimulating hormone receptors whereas neuraminidase has no such effect.

Cell Line↗
PubMed1976

Protective action of beta-carotene against lethal photosensitization of fibroblasts in vitro.

Cell culture experiments using haematoporphyrin photosensitized bovine hoof fibroblasts and long-wave uv-irradiation revealed two distinct and separable patterns of lethal photosensitization according to two different sensitization procedures: (1) Photosensitization of cell membranes by short exposure (5 min) of cells to haematoporphyrin. (2) Cytoplasmic photosensitization elicited by a 2 h exposure of cells to haematoporphyrin. Cell membrane photosensitization was reversible by incubation of cells in serum which removed surface bound haematoporphyrin; cytoplasmic photosensitization was irreversible. Beta-carotene was tested in these two systems and the following results were obtained: (1) Preincubation of bovine hoof fibroblasts in beta-carotene protects from lethal haematoporphyrin photosensitization. (2) Protection with beta-carotene is achieved against both types of photosensitization. (3) The protective effect of beta-carotene depends upon the duration of pretreatment, reaching a maximum after 7 days. (4) Beta-carotene protection is maintained even after trypsinization of bovine hoof fibroblasts and withdrawal of beta-carotene from the medium for 24 h or more. (5) Haematoporphyrin sensitized bovine hoof fibroblasts show a distinct pattern of red fluorescence for each type of photosensitization. Incubation of bovine hoof fibroblasts in beta-carotene prior to haematoporphyrin photosensitization results in a pronounced reduction of red fluorescence. Some of these data indicate that beta-carotene acts, at least in cell membrane photosensitization, at the level of the cell membrane into which it appears to be incorporated.

Animals↗
PubMed1976

The fate of Staphylococcal exfoliatin in newborn and adult mice.

The distribution and excretion of the staphylococcal exfoliatin was investigated following in vivo administration of highly purified 125I-labelled exfoliatin fractions to adult and newborn mice. Adult mice excrete approximately one-third of a test dose by 3 hours as compared to a fifteenth of a test dose excreted by newborn mice. Accordingly, blood tracer radioactivity reaches a relatively higher peak and shows a slower decline in newborns than in adults. The urine of adult mice contains considerable biologically active exfoliating material. Both nephrectomized and carbon tetrachloride-poisoned adult mice injected with exfoliatin develop generalized exfoliation whereas comparable doses in untreated controls have no effect. On the other hand, subtotal hepatectomy, followed by injection of exfoliatin, does not lead to exfoliation. We conclude that renal immaturity is a critical factor responsible for the susceptibility of neonates to generalized staphylococcal scalded skin syndrome.

Age Factors↗
PubMed1976

[Formation of nitrites from nitrates in the digestive tract].

The authors performed in vitro incubations of gastrointestinal mucosae and contents in the rat, under anaerobiosis, in the presence of nitrates. Nitrate disappearance and nitrite appearance amounts were measured in the different incubation media. From these works it follows that a certain quantity of nitrates are actually reduced to nitrites specifically by the ileo-caecal microflora of rats and perhaps, to a lower degree, by the action of a nitrate-reductase which may occur in the digestive mucosae. Moreover, the authors carried out in situ perfusions into the small intestine of rats, by adding nitrates to the perfusion liquid at a concentration of 400 mg per litre. It was thus demonstrated that the nitrate-absorbing kinetics is very rapid but those nitrates do not gather in the blood; besides, the presence of nitrites in the perfusion medium indicates a possible nitrate reduction in the intestinal gut.

Anaerobiosis↗
PubMed1976

[Influence of small intestine shunt and small intestine resection on gastrin secretion].

In 10 healthy controls, in 3 patients with subtotal resection of the small intestine and in 7 patients with jejuno-ileal bypass gastric ackd secretion and serum gastrin were determined in the basal state and after stimulation. The patients with short bowel revealed basal and pentagastrin stimulated gastric acid secretion in the lower normal range. Hypergastrinaemia, however, was present in these patients in the basal state and after food stimulation of gastrin release, while in patients with jejuno-ileal bypass basal and postprandial serum gastrin concentrations were within the normal range. These data suggest, that hypergastrinaemia in patients with short bowel is due to dimished gastrin catabolism and that the small intestine plays a significant role in gastrin inactivation.

Gastrins↗
PubMed1975

[Gastric irrigation and secretion in the ligatured or fistuled pylorus rat upon influence of intra-duodenal olive oil (author's transl)].

Pylorus ligature hides the inhibitory effects of endogenous cholecystokinine-pancreozyme (CCK-PZ) on gastric mucosal secretion and irrigation, whereas the juice collected through transduodenal pyloric fistula makes this phenomenon obvious. It appears that the pyloric fistula encourages inhibition of gastrinic secretion, so that the CCK-PZ can achieve its effects.

Animals↗
PubMed1975

[Electron microscopic identification of thymidine-incorporating cells in a population with a low turnover rate. Application to deep lung cells].

Many cells difficult to identify by photon microscopy were identified by using serial thin and semithin epoxy section. This procedure made it possible to carry out significant statistical analysis on a restricted number of sections. When applied to the study of cell renewal in the deep lung, each cellular proliferation could be quantified.

Animals↗
PubMed1975

[Dynamic comparative study of the intraalveolar cell population after intratracheal injection of beryllium hydroxide and aluminum hydroxide in the rat].

A sequential quantitative analysis of free alveolar cells was performed on S.P.F. rats after intratracheal injection of Be (OH)2 and Al (OH)3. The induced lesions were entirely restored 20 days after the initial injection. Beryllium hydroxide inhibited DNA synthesis in the free alveolar macrophages and the transeptal cellular flow could be evidenced. Aluminium hydroxide increased the number of free cells without inhibiting DNA synthesis. Quantitative variations of polymorphonuclears, lymphocytes and macrophages were correlated with changes in the alveolar environment. A strong direct correlation between the number of lymphocytes and DNA synthetizing macrophages was shown out. This reaction was not observed in beryllium treated rats.

Aluminum↗
PubMed1975

[Effect of anisole, anethole, butylhydroxyanisole and safrole on intestinal absorption in the rat (author's transl)].

Using an in situ method of perfusion for rat intestine, we have studied the effect of anisole, anethole, butylhydroxyanisole (BHA) and safrole on the absorption of three metabolites: glucose, butyric acid and methionine. At a concentration of 2 mg/ml of perfusion medium, safrole, and particularly BHA, reduce the absorption of glucose and methionine but have no effect on that of butyric acid. These results could be explained by variations in intestinal water absorption induced by methoxybenzene compounds, or by changes in the digestive mucosa seen in histological studies.

Alkenes↗
PubMed1975

Glycocalyx of epidermal cells in vitro: demonstration and enzymatic removal.

Guinea-pig epidermal cells in culture possess a glycocalyx coat similar to that in vivo, as revealed by the ruthenium red stating technique. Trypsin, phospholipase C, and lysozyme do not produce any changes of the glycocalyx, while hyaluronidase and neuraminidase lead to partial and subcomplete removal respectively. Cells stripped of their glycocalyx coat by neuraminidase do not detach from the support and do not show any signs of toxicity. There is complete reconstitution of the glycocalyx within 24 hr.

Animals↗
PubMed1975

Staphylococcal toxic epidermal necrolysis: pathogenesis and studies on the subcellular site of action of exfoliatin.

An exfoliating substance elaborated by certain phage Group 2 staphylococci causes toxic epidermal necrolysis. Both in man and in the newborn mouse, intraepidermal cleavage is the predominant histologic feature following exposure to this toxin. Electron microscopic study of sequential biopsy specimens obtained from neonatal mice and from organ cultures of human skin revealed intercellular cleavage and cell separation. The extracellular nature of the exfoliative process was confirmed in several ways: (1) perfused tracers did not penetrate cells during cell separation; (2) cultured cells exposed to high doses of exfoliating fractions demonstrated no signs of injury; and (3) cleaved surfaces examined by scanning electron microscopy and surface replication demonstrated intact plasma membranes. When fractions capable of inducing exfoliation were applied to cultured keratinocytes of fibroblasts, sperm, or lymphocyte suspensions, and to human or mouse skin in vivo, they did not alter the distribution or intensity of concanavalin A binding, ruthenium red staining, pemphigus antibody binding, or HL-A surface antigens. Therefore, while the pathogenesis of staphylococcal toxic epidermal necrolysis involves intercellular cleavage, the molecular cell surface target remains unknown.

Animals↗
PubMed1975

[Quantitative evaluation and homeostasis of alveolar macrophage populations].

The rat's alveolar macrophage population is a biological constant which significantly varies according to the season, the strain and the bacteriological state,in healthy animals. The percent rate of excreted macrophages remains constant in spite of the physiological changes of the total population variation. This rate is close to 3,5 %. So, the variations of the population are due to the changes in cell arrival. The possible different sources of alveolar macrophages are analysed and evaluated. The direct monocyte source is not sufficient to insure the stability of this population. Division of intra alveolar macrophage enables homeostasis. In pathological conditions, variations of cell populations result from two effects : reduction of excretion, positive or negative changes in cellular influx.

Aerosols↗