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Biomedical subjects

C Steffen

Publications and source records attributed to C Steffen.

At least 73 records · Page 4Linked to original sources
PubMed1984

Experimental synovitis induced by intraarticular administration of alpha 2-macroglobulin-proteinase complexes.

Rheumatoid synovial collagenase was prepared from tissue cultures from rheumatoid arthritis patients, obtained after synovectomy. Alpha 2-macroglobulin was isolated from human plasma and complexed with collagenase or trypsin. Formation of both types of complexes was proven by sodium dodecyl sulfate and rate electrophoresis. Normal rabbits were injected intraarticularly into the right knee, on days 0, 3, and 6, with either alpha 2-macroglobulin-collagenase or alpha 2-macroglobulin-trypsin complexes. Control injections of alpha 2-macroglobulin, trypsin, or rheumatoid synovial collagenase were applied to the left knee joint cavity. Groups of rabbits were killed 18 hours, 1 week, or 3 weeks after the last injection, and cellular exudation into synovial fluid and morphologic alterations of synovium were investigated. Joints injected with alpha 2-macroglobulin showed no synovitis, while joints injected with collagenase showed an experimental synovitis. Alpha 2-macroglobulin-proteinase complexes, however, induced a synovitis, which was more severe than that occurring after injection of proteinases only. In the early stages, synovium showed perivascular accumulation of inflammatory cells, infiltration with neutrophils, proliferation of synovial cells, and exudation of inflammatory cells into synovial fluid. Later stages were characterized by infiltration with mononuclear cells and fibroplasia.

Animals↗
PubMed1984

The effect of imipramine and desipramine on mixed function oxidase in rats.

The effects of imipramine and desipramine on hepatic mixed function oxidase were measured in male Wistar rats. Both antidepressants increased hepatic cytochrome P-450 when given b.i.d. for 7 or 14 days. In vitro demethylation of imipramine was rather depressed than increased. 14CO2 exhalation from [N-methyl-14C] benzphetamine was increased by pretreatment with the antidepressants as well as with phenobarbital, but imipramine had no influence on the exhalation of the label from [6-methoxy-14C]- or [7-methoxy-14C]-scoparone. No difference was observed between treatment with imipramine or desipramine. It is concluded that changes of the demethylation rate of imipramine are not responsible for its delayed elimination observed after chronic treatment (Daniel et al. 1981).

Animals↗
PubMed1984

Immune complexes in juvenile chronic arthritis.

Twenty children with juvenile chronic arthritis (JCA) and two children with SLE were investigated as to the existence of immune complexes in a long-term survey over 24 months. Two different methods were applied, a solid phase C1q RIA and a polyethylene glycol precipitation test. Detection of immune complexes was compared to the course of the disease and other laboratory data. C1q RIA showed a distinctly higher number of positive tests than the PEG precipitation test. The presence of immune complexes appears to be transitory in the course of JCA, as was demonstrated by C1q RIA. A connection with a more advanced stage of the disease is postulated. The positive test can be regarded as a prognostic parameter which, however, cannot be used for the diagnosis of JCA.

Adolescent↗
PubMed1984

Erythrocyte membrane alterations as the basis of chlorate toxicity.

The effects of sodium chlorate and of sodium nitrite on human erythrocytes were studied in vitro. Nitrite rapidly oxidised haemoglobin and glutathione; reduction of methaemoglobin (Hbi) by methylene blue was complete during 3 h of incubation with nitrite. With chlorate, a concentration-dependent lag phase was seen before Hbi was formed. After prolonged incubation, Hbi could no longer be reduced with methylene blue. Several other effects were observed that explain the clinical picture of chlorate poisoning which involves haemolysis followed by disseminated intravascular coagulation and renal failure: increased permeability to cations, increased resistance to hypotonic haemolysis and prolonged filtration time through polycarbonate membranes with cylindrical pores of 5 micron diameter. This suggests an increased membrane rigidity due to membrane protein polymerisation, as demonstrated by SDS polyacrylamide gel electrophoresis. Simultaneously, erythrocyte enzymes were inactivated, primarily glucose-6-phosphate dehydrogenase which is necessary for the therapeutic effect of methylene blue. This explains the inefficacy of methylene blue in the treatment of a case of chlorate poisoning that we observed (Arch. Toxicol., 48 (1981) 281).

Chlorates↗
PubMed1984

Marjolin's ulcer. Report of two cases and evidence that Marjolin did not describe cancer arising in scars of burns.

Two patients who developed malignant neoplasms in scars (Marjolin's ulcers) are described in this report. The first patient developed a squamous cell carcinoma in the site of a chronic, draining urinary fistula. The malignancy later metastasized. The second patient developed a squamous cell carcinoma and a basal cell carcinoma in a scar from a burn and a keratoacanthoma in a scar from a vaccination. The history of the eponym "Marjolin's ulcer" is traced and it is pointed out that Marjolin did not describe the condition he is eponymously credited with, but that the false ascription to him arose over time.

Aged↗
PubMed1984

Modification of microsomal lipid peroxidation and drug metabolism by cytoplasmic copper.

NADPH-dependent microsomal lipid peroxidation (LPO) can be influenced by addition of cytoplasmic supernatant as was demonstrated by Gram and Fouts (Arch. Biochem. Biophys. 114, 331-335, 1966). Small quantities of hepatocellular supernatant stimulate LPO, higher concentrations are inhibitory. These opposed effects depend on the relative concentrations of copper and iron, either as ions or protein-bound. A mathematical model is given to predict the formation of malondialdehyde as indicator of LPO in dependence of these metals. The copper-containing superoxide dismutase was shown to be without effect on LPO, whereas coeruloplasmin was inhibitory. Inhibition of LPO by copper ions or by TRIS buffer increased the linearity of microsomal ethylmorphine demethylase.

Animals↗
PubMed1983

Improved method to measure erythrocyte filtration times increased extremely by chlorate.

A method is presented that allows the measurement of erythrocyte filtration times that are extremely prolonged. Filtration times through polycarbonate sieves are increased by a factor of 40 after 2 h incubation with 30 mM sodium chlorate. This increase in red cell rigidity offers an explanation for the haemolysis observed in chlorate poisoning in vivo.

Chlorates↗
PubMed1982

Concurrence of condylomata acuminata and bowenoid papulosis: confirmation of the hypothesis that they are related conditions.

Lesions of condyloma acuminatum and of bowenoid papulosis, confirmed histologically, were present concurrently on the penis of a 44-year-old man. All of the lesions regressed spontaneously. This phenomenon suggests that these two conditions, condyloma acuminatum and bowenoid papulosis, are related to one another and that bowenoid papulosis is simply condyloma acuminatum with histologic features of squamous cell carcinoma in situ.

Adult↗
PubMed1982

Influence of x-ray treatment on antigen-induced experimental arthritis.

Six groups of 3 rabbits each were immunised with ovalbumin and received one intra-articular injection of antigen. The animals of 3 groups received local x-ray irradiation of 600 rads for 8 minutes to the right knee joint 12 days after the intra-articular challenge. Animals of the other 3 groups were not irradiated. The antigen-induced arthritis was investigated by determining the exudation is synovial fluid and by histological study of the synovium examined 48 hours, 7 days, and 4 weeks after the irradiation date. All animals in the nonirradiated groups showed a distinct chronic synovitis. Irradiated animals showed almost no synovitis 48 hours and 7 days following irradiation. In 2 rabbits synovitis had reappeared 4 weeks after irradiation with findings similar to those in the control groups. Only one animal still showed an inhibition of synovitis. X-ray irradiation of non-challenged knees did not induce any pathological changes. This time-limited effect of one local irradiation on antigen-induced arthritis seems to be mainly an anti-inflammatory action. Local immunological inhibition might possibly operate too. X-ray induced inhibition of synovitis is compared with the effect of locally injected radiocolloids.

Animals↗
PubMed1982

[Influence of the mushroom poison gyromitrin on the lipids of rat liver (author's transl)].

Gyromitrin, the main poison of the false morel Gyromitra esculenta, causes enlargement of the liver in rats. The content of triglycerides and total cholesterol were increased in the liver homogenate and microsomal fraction but not in the mitochondrial fraction. On the other hand the content of phospholipids was found to be decreased. The enhanced incorporation of [14c]-acetate into the lipids of rat livers after gyromitrin indicates an increased rate of lipids synthesis. The diminution of the phospholipids is caused mainly by a loss of phosphatidyl ethanolamine (PE) although after a short pulse with [14C]-ethanolamine the specific radioactivity of the isolated phosphatidyl ethanolamine corresponded to that of the controls. Since the content of phosphatidylcholine (PC) remained unchanged, the PC/PE-ratio was shifted from 2.3 to 4.5. These effects were reversible within 48 h. Inhibition of the synthesis of highly unsaturated fatty acids by the microsomal monoxygenase system is discussed as the primary reason for the above observations this inhibition possibly being due to active metabolites of gyromitrin which destroy the monoxygenases.

Acetaldehyde↗