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Biomedical subjects

R Rohrbach

Publications and source records attributed to R Rohrbach.

At least 37 records · Page 2Linked to original sources
PubMed1980

[Capillary embolization. Part I: occlusion of the entire arterial system of the rat kidney (author's transl)].

Effect of tumor embolization is limited by parasitary blood supply. The influence of those collaterals should be decreased by transporting the embolization medium into the capillaries and tumor sinusoids. Controlled and safe capillary embolization is developed from studies of obtainable radiodensity, viscosity, and occlusion mechanism of Gelfoam-powder, IBC, and Ethibloc. The efficiency of these substances is compared to simple arterial ligation in experimental series with 400 Wistar rats. It is shown that ligation is comparable to insufficient capillary transport of the medium leaving islands of microscopically intact parenchyma. Easy application and total necrosis is guaranteed only by Ethibloc. Success of embolization is strictly volume dependent. Preinjected glucose is mandatory for homogenous distribution and peripheral transport.

Animals↗
PubMed1980

[Renal embolisation, renal cystography and percutaneous nephrostomy (author's transl)].

In renal disease, therapeutic procedures performed by radiologists include embolisation, cystography with obliteration and percutaneous nephrostomy. More than 72 therapeutic occlusions of the renal artery by balloon, coil, and gelfoam are presented. Basic differences in technique of application and in the mechanism of Ethibloc in comparison to other kinds of embolisation material are pointed out. In 61 diagnostic punctures of renal cysts, guided by sonograpny, 31 were treated by injection of Lipiodol. As in cystography, the combination of sonography and radiology proved to be highly valuable in 37 percutaneous nephrostomies. Technique, indication, contraindication, and complication of renal embolisation, renal cystography and percutaneous nephrostomy are briefly discussed.

Adenocarcinoma↗
PubMed1979

Autoantibody specific for the glomerular mesangium and Bowman's capsule in man.

Investigation of serum from a nominally healthy subject revealed an unusual autoantibody with specificity for the glomerular mesangium and Bowman's capsule. Immunofluorescence studies on rodent kidney sections revealed typical mesangial fluorescence and intense linear staining of Bowman's capsule. The antibody was organ, but not species, specific and did not correspond to any previously described antibody with anti-mesangial activity (e.g. anti-actomyosin or anti-fibronectin). Intravenous injection in mice resulted in heavy mesangial deposition of antibody within one hour, the antibody disappeared within 2--4 weeks, and no urinary abnormalities were seen. Retrospective analysis of clinical data revealed a history of chronic hepatitis and possible drug abuse, but no evidence for impaired renal function at any timepoint. To our knowledge this is the first report of specific anti-mesangial antibody in man, the pathogenetic relevance remains unclear.

Animals↗
PubMed1979

Pathogenetic role of mesangial immune deposits.

This investigation was designed to clarify the pathogenetic role of immune complexes within the mesangium. We administered a ferritin-protein antigen to rats which localised and persisted within the mesangium. Subsequently administration of anti-ferritin antibody resulted in binding of antibody to the mesangially located antigen. The effect of this immune complex formed in situ was studied in long-term experiments and no evidence of glomerular impairment was seen. These results lend support to the view that an immunological process, confined to the mesangium, may not necessarily compromise renal function.

Animals↗
PubMed1978

Changes in cell population kinetics during epidermal carcinogenesis.

The changes in cell population kinetics in response to a mechanical stimulation by wounding were studied in a hyperplastic epidermis, papilloma and a squamous cell carcinoma of the mouse dorsal skin induced by repeated treatments with 20-methylcholanthrene. The G0 cell population, which consists of about 66% of the basal cells in the dorsal epidermis of the normal mouse, disappeared in hyperplastic epidermis, papilloma and carcinoma. The zone of proliferating cells enlarged in the papilloma, including several supra-basal layers, in contrast to its strict localization in the basal layer in hyperplastic epidermis. Proliferating cells were distributed in almost all areas in the carcinoma without localization. The normal responses to wounding were preserved in the hyperplastic epidermis, except for the absence of G0 cells, while the papilloma and carcinoma showed no increase in proliferating cells or shortening of the cell cycle time. From the view-point of cell population kinetics, papilloma and carcinoma are regarded as the tissues in which the flexible control mechanisms of irreversible cell differentiation to mature cells and of the length of cell cycle time are lacking.

Animals↗
PubMed1977

Effects of cellophane tape stripping of mouse skin on epidermal growth regulators (chalones).

Variations in epidermal chalones after a single surface application of methylcholanthrene and croton oil have been described in previous papers. This paper reports a study of the effect of adhesive tape stripping of the skin on epidermal growth regulators (G1 and G2 chalones). Pieces of adhesive tape were applied 6 times to the same area of skin in groups of mice. The short-term effects of tape stripping on epidermal DNA synthesis and on mitotic rate were studied at different intervals after stripping. Other groups of mice were killed at similar time intervals after stripping, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal DNA synthesis and mitotic rate was assayed in normal hairless mice. The resulting inhibitions were interpreted as an expression of the concentration of G1 or G2 chalone in the skin extracts. The first experiment confirmed that cellophane tape stripping gives rise to a short block in epidermal mitotic activity and probably also in DNA synthesis. This was followed by bimodal peaks of increased activity, the two maxima of labelling index being found on days 2 and 6, and the two maxima of mitotic rate on days 1-2 and 7. The concentrations of the two chalones in the skins of treated animals varied in inverse proportion to the alterations in the DNA synthesis and the mitotic rate, with one exception. Here there was initially a depression of the mitotic rate and a low concentration of G2 chalone. This was interpreted as a short reaction of the basel cells to the stripping trauma. It is concluded that adhesive tape stripping removes the differentiating cells and injures some basel cells, simultaneously altering the content of G1 and G2 chalones. The resulting increase in the rates of DNA synthesis and mitosis lasts only until the number of cells is high enough to produce growth-regulating substances (chalones) again. This theory may explain the changes observed. Since similar reactions are seen after both carcinogenic and co-carcinogenic chemical injury of the epidermis, the reaction pattern seems to be a general response to cell injury or cell removal.

Animals↗
PubMed1977

[Correlation between microangiography and histological findings in renal carcinomas (author's transl)].

Arterial, venous and simultaneous arterial and venous injections with radio-opaque dyes were carried out under manometric control on three renal cell carcinomas following nephrectomy. The micro-angiographic appearances were then correlated with the histological findings. The radiologically abnormal vessels correspond with sinusoids with thin, capillary-like walls containing localised areas of thickening in a collagen-rich stroma. Both micro-angiographically and histologically, the sinusoidal connections can be demonstrated between the edge of the tumour and normal tissue. Arterio-venous anastomoses were not found. The angio architecture and micro-angiographic pattern in renal cell carcinomas is described. The significance of these changes in the circulation is discussed and its significance in carrying out pharmaco-angiography and retrograde phlebography is pointed out.

Adenocarcinoma↗
PubMed1977

Effects of bleomycin on the epidermal content of growth-regulatory substances (chalones).

Hairless male mice were given 2 mg Bleomycin i.p. on two successive days. At different time intervals from 1 to 10 days after the last Bleomycin injection, groups of animals were killed and water extracts of hemogenized skin were made. These extracts, supposed to contain the epidermal G1 and G2 chalones, were injected into female hairless mice, and their growth inhibitory potency determined by two methods. 5 mg of lyophilized crude skin extract were injected i.p. together with Colcemid, and the animals killed 4 hr later. The number of Colcemid-arrested mitoses was determined, and was considered to be a measure of the G2 inhibitor present in the skin extracts. 10 mg of the same extracts were injected i.p., and these animals also got 3H-TdR i.p. 12 hr later, and were killed after a subsequent 30 min. The epidermal LI was determined, and was considered to be a measure of the epidermal G1 factor in the skin extracts. The results obtained were compared to the effect of Bleomycin alone and to the effects of skin extracts from non-Bleomycin-treated animals. The results show that Bleomycin provoked slight alterations in the growth-inhibitory potency of the G1 chalone, whereas significant effects were seen in the G2 chalone, There was an increased amount of growth-inhibiting factors on days 2 and 3, and on days 8-10. The results are discussed and it is concluded that the most probable hypothesis is that Bleomycin, in addition to its known inhibition by accumulation of cells with high growth inhibitory potency. An initial, additional direct effect of Bleomycin on the chalone system cammot be excluded.

Animals↗
PubMed1977

[Efficacy of experimental renal embolization with microspheres. Additionally, a critical report on the complication rate of intra-arterial embolization with particles (author's transl)].

Renal embolization was performed in 12 dogs using the Seldinger technique and microspheres 250 +/- 40 micrometer in diameter. Periodical arteriography, microangiographies and histological analysis was carried out to control the efficacy of embolization. As a result, renal arteries could be embolized wi. th microspheres, however, because of statistical distribution there were histologically anemic and normal parenchyma situated closely together. In more than 50% there was a reflux of microspheres which could only be detected by histological examination, while angiographies showed a totally normal vascular pattern. Microspheres should not be used in clinical embolization. Experimental investigation of embolization materials must almost embrace histological analysis.

Animals↗
PubMed1977

[Xanthogranulomatous pyelonephritis in a young child (author's transl)].

UNLABELLED: Case report on a boy aged 4. The whole of the right kidney showed changes of xanthogranulomatous pyelonephritis. HISTOLOGY: dense granulomatous infiltrations of xanthome cells, epitheloid and plurinuclear giant-cells, lymphocytes and plasma cells. Diagnostic proof was based on the xanthome cells, large histocells with partially pycnotic nucleus and wide margin of cytoplasm. This condition has, so far, been seen only very rarely in children.

Child, Preschool↗
PubMed1976

[Transvenous kidney puncture. New procedure for withdrawal of kidney tissue].

A transvenous catheter technique for renal puncture is described which was successful in 9 of 11 punctures performed in 8 dogs. Macrohematuria was not observed in any case. Autopsy revealed only small subcapsular hematomas. The advantage of this procedure is the reduced risk of bleeding achieved by peripheral puncture and by-passing of the great central vessels with aid of phlebographic controls. Moreover localization of kidneys by excretion urography--impossible in patients with renal insufficiency--is unnecessary.

Animals↗
PubMed1976

Effects of croton oil on epidermal growth regulators (chalones).

Variations in epidermal chalones after a single surface application of methylcholanthrene have been described in previous papers. This paper reports a study of the effect of croton oil on epidermal growth regulators (G1 and G2 chalones). Hairless mice received a single topical application of 0.2 ml 0.25% acetone solution of croton oil. Control mice received only acetone. The short-term effect of croton oil on epidermal DNA synthesis and mitotic rate was studied. Other groups of croton oil-treated and acetone-treated mice were then killed at similar time intervals, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal DNA synthesis and mitotic rate was assayed in normal hairless mice. The resulting inhibition was interpreted as an expression of the concentration of G1 and G2 chalones, respectively, in the skin extracts. The first experiment confirmed that a single croton oil application provokes a short block in epidermal mitotic activity and probably also in DNA synthesis. This was followed by bimodal peaks of increased activity, the two maxima of mitotic rate on days 2 and 7. The concentration of the two chalones in the skins of treated animals varied in inverse proportion to the alterations in the DNA synthesis and the mitotic rate, with one exception. There was here initially a depression both of the mitotic rate and a low concentration of G2 chalone. This was interpreted as a short, initial direct effect of croton oil on the G2 chalone present at the time of application. It is concluded that croton oil application injures and kills epidermal cells, with subsequent alterations in the content of G1 and G2 chalones. This theory may explain the changes observed. The effects of croton oil on the amount of G1 and G2 chalones in the skin are probably related to the direct, toxic, cell-killing effect of croton oil, and not to its specific cancer promoting potency.

Animals↗
PubMed1976

Some effects of bleomycin on the proliferation, maturation time and protein synthesis of hairless mouse epidermis.

Hairless mice were given 2 mg Bleomycin i.p. in 1-0 ml saline on two successive days. By a stathmokinetic method, by micro-flow fluorometry and by autoradiography certain kinetic parameters were measured during 10 days after the last injection. Cell counts were made and the turnover time of the differentiating cells estimated. Protein synthesis was estimated by the uptake of radioactive histidine, and dry cell mass measured by weighing. Bleomycin affected cell proliferation in the epidermis by depressing biphasically both the number of cells in, and the passage of cells through, the cell cycle phases: S, G2 and M, most probably by directly affecting late G1 cells and cells in mitosis. The time between the two minima of depressed DNA synthesis corresponded to the mean generation time of the basal cells. Histidine uptake and dry cell mass were slightly affected, but the turnover time of the differentiating cells was prolonged. Bleomycin thus had a strong long-lasting inhibitory effect on epidermal cell proliferation and a marked inhibitory effect on epidermal cell maturation in mice.

Animals↗