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Biomedical subjects

G Lüders

Publications and source records attributed to G Lüders.

At least 19 recordsLinked to original sources
PubMed1987

[Exogenously induced diseases of the mouth mucosa].

Exogenously induced diseases of the oral mucous membrane and the lips caused by chemical, actinic, or mechanical irritations, by drugs, by infections, as well as by dental materials are usually characterized by definite morphology. We report on these diseases, their assignment to various groups of releasing agents, and their course. In particular, we present current developments of dental materials and their relationship to alterations in the oral mucous membrane.

Dental Materials↗
PubMed1986

[Electron microscopy and histochemical studies of the origin and function of myoepithelioid cells in glomangioma and peripheral barrier arteries].

Epithelioid cells (myoepithelioid cells, glomus cells) are a structural element characteristic of Hoyer-Grosser shunts (glomus organs, arterio-venous epithelioid cell glomerula) and Bailey's glomangioma (Masson's angio-neuromyome-artériel, glomus tumors). Their functional importance cannot be estimated without knowledge of their histogenetic origin. The myoepithelioid cells are derived from smooth muscle cells, which can be shown ultrastructurally, histochemically, or by light microscopy.

Endothelium↗
PubMed1985

Selective toxicity of neocarzinostatin-monoclonal antibody conjugates to the antigen-bearing human melanoma cell line in vitro.

Monoclonal antibodies (IgG1) against high molecular weight antigen A-1-43 on human melanoma cell line A-375 were successfully linked to the anti-tumour protein neocarzinostatin (NCS) using the heterobifunctional reagent N-succinimidyl 3-(2-pyridyldithio)-propionate (SPDP). The conjugate retained both the reactivity of the antibody and the toxicity of the drug. The antigen-bearing cell line A-375, antigen-lacking cell line MeWo and normal skin fibroblasts were exposed to NCS-monoclonal antibody conjugates. As negative control, cells were also treated with free NCS and NCS coupled to normal mouse IgG1 antibodies. Inhibition of 3H-thymidine uptake after treatment was used to measure the biological activity of the cytotoxic drug complex or substance, respectively. Comparing the inhibition dose for 50% uptake (ID50) it was found that the monoclonal antibody-drug complex is about 100 times more toxic for the antigen-bearing cell line than free NCS or normal mouse IgG1-NCS. This high toxicity is due to a local increase of drug concentration on these cells. With the two cell lines lacking the appropriate antigen no significant differences in the ID50 values were observed. A selectivity factor of 40-50 was obtained by comparing the cytotoxic effect of the monoclonal antibody-NCS conjugate upon the antigen-bearing as opposed to the antigen-lacking cell type. These data demonstrate, that the toxicity of NCS can be directed by monoclonal antibodies to human tumour cells carrying the corresponding surface antigen.

Antibiotics, Antineoplastic↗
PubMed1976

[Effects of longterm HCG administration on testicular function in hemodialysis patients (author's transl)].

Thirtheen male patients with chronic renal failure undergoing regular dialysis treatment (2 X 8-10 hours/week) were treated with gonadotropins (HCG, Primogonyl) primarily 2 X 2,000 IU/week and later 2,000 IU/week. Before HCG administration and during 4-months HCG-therapy testosterone, dihydrotestosterone, Androstandiol, LH and FSH levels were determined by RIA-methods in 7-14 days intervals. Before HCG-application plasma testosterone levels were low and did not increase in the course of regular dialysis treatment. Derivates from testosterone like dihydrotestosterone and Androstandiol were elevated in plasma, presumbably because of accumulation in renal failure. LH-levels were slightly elevated on the average. FSH-levels showed a high individual variation but also seemed to be elevated on the average. HCG stimulation by exogenous HCG administration for short time resulted in a insufficient rise of testosterone levels as compared to normals. During prolonged HCG administration plasma testosterone levels increased to normal but dropped immediatly after cessation of therapy or reduction to less than 2,000 IU HCG twice/week. Body weight, plasma proteins, haematocrite and fertility did not improve significantly. These results indicate that in chronic renal failure androgen synthesis by testicular tissue is seriously impaired and does not improve under usual dialysis treatment. Feedback regulation of testosterone levels by increase of LH levels seems not to be sufficient although pituitary response is found to be normal. This may be explained by elevated levels of testosterone derivates which exert negative feedback effects.

Adult↗
PubMed1976

[Structural changes of the basement tubule membrane in the so-called Sertoli cell syndrome (author's transl)].

In the so-called Sertoli cell syndrome nearly always club shaped invaginations of the basement tubule membrane with intact cellule membrane can be seen. These protuberatons ultrastructurally prove to be multiplicated piles of the lamina densa of the basement membrane. The cells in the Sertoli cell syndrome show a quantitatively and qualitatively reduced pattern of enzymes in contrast with the active Sertoli cells.

Basement Membrane↗
PubMed1976

[A defect of the head-flagellum-connection of human spermatozoa].

A spermatozoa defect with an obligate heat-flagellum-crack which implies infetility is reported. Hereby the connection of the flagellum with the nucleus is loosened. The axis of the flagellum is displaced from the axis of the nucleus up to 160 degrees. The motility of these spermatozoa is not perceptibly disturbed.

Adult↗
PubMed1976

[Investigations of the morphology and the function of human Sertoli cells (author's transl)].

Ultrastructurally and enzyme histochemically two types of activities of Sertoli cells are to be proved. By means of closest membrane contact and intensive energetic changes of substances, the active cells participate largely in the ripening of spermatozoa. Steroid biosynthesis in Sertoli cells is possible according to their pattern of organelles and enzymes. The ultrastructure of Charcot-Böttcher's crystalloids and the other characteristic inclusions in the cytoplasma of the Sertoli cells as well as implications to their function are described.

Androgens↗
PubMed1976

On the structure and importance of the epithelium in the human ductus epididymidis (author's transl).

In the wall of the ductus epididymidis rosette-like crystalloids and in the epithelium three types of cells are to be found: round basal cells, pale cylindrical epithelium and dark cylindrical epithelium. The latter shows a high metabolic activity with lamellar rough ergastoplasm and low vesicular secretion. Apocrine separation of drops of secretion is seen only sporadically. The functional relations between these states, the possibilities of biosynthesis in the epididymis, and the maturing of spermatozoa are discussed.

Adult↗