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Biomedical subjects

M Bergmann

Publications and source records attributed to M Bergmann.

317 records · Page 18Linked to original sources
PubMedDate not supplied

Potential prognostic value of C-erbB-2 expression in medulloblastomas in very young children.

PURPOSE: The expression of the c-erbB-2 oncogene was studied in childhood medulloblastoma to evaluate its prognostic value, which has been claimed previously. PATIENTS AND METHODS: Tumor material from 45 patients < 15 years old at diagnosis was studied using 3 monoclonal antibodies against the internal and external domains of the c-erbB-2 oncogene product. RESULTS: Six of the 45 (13%) tumor specimens were found to be positive. C-erbB-2 expression was found more often in patients < 3 years old at diagnosis (4 of 15 patients, 27%) than in older patients (2 of 30, 6.6%). During the follow-up period (5.8 +/- 2.8 years) all patients with c-erbB-2 expression died of disease (after 1.2 +/- 0.7 years). Kaplan-Meier estimation revealed a highly significant correlation of c-erbB-2 expression and survival (p = 0.002). A further study of the expression of synaptophysin and the glial fibrillary acidic protein (GFAP) in the 45 tumors revealed a negative correlation of the expression of c-erbB-2 and these proteins. CONCLUSION: C-erbB-2, which may be predominantly expressed by less differentiated tumors, was found to delineate a poorer prognostic subgroup, especially when diagnosed in patients < 3 years old.

Adolescent↗
PubMedDate not supplied

Photoperiodic influence on the morphology and the androgen receptor level of the ventral prostate gland and seminal vesicles of the Djungarian hamster (Phodopus sungorus).

The influence of long (light:darkness LD 16:8) and short (LD 8:16) photoperiods on the morphology of the ventral prostate gland and the seminal vesicles of the Djungarian hamster was investigated. At LD 8:16, the wet weight of the glands was reduced to 15-20% of the values found in animals living in LD 16:8 conditions, the protein content was reduced to 3-4%. The glands showed distinct signs of atrophy and inactivity under short-day conditions. The androgen receptor levels were determined in both accessory sex glands. The receptor levels were comparable in both glands; the absolute values related to the whole glands remained about constant in animals living in long and short photoperiods despite a reduction of the androgen levels in short photoperiods.

Animals↗
PubMedDate not supplied

The influence of LH and/or FSH on Leydig and Sertoli cell morphology after testicular involution in the Djungarian hamster, Phodopus sungorus, induced by hypophysectomy or short photoperiods.

In the Djungarian hamster, Phodopus sungorus, the morphological alterations of Sertoli and Leydig cells were investigated under the influence of gonadotropins (LH and/or FSH) after testicular regression induced either by hypophysectomy or photoinhibition. Stimulation with LH or LH/FSH lead to a redifferentiation of morphological features of Leydig cells such as nuclear structure, smooth endoplasmic reticulum and size of cell and nucleus area within 7 days of hormone treatment. Similarly, stimulation with FSH or LH/FSH caused redifferentiation of Sertoli cell nuclear structure, rough endoplasmic reticulum and nuclear size within 7 days. Incomplete restoration of Leydig and Sertoli cell morphology was observed under FSH and LH treatment respectively. In both Leydig and Sertoli cells combined LH and FSH application resulted in an increased response in respect to morphological redifferentiation, possibly indicating paracrine regulatory mechanisms. In all groups treated an intact blood-testis barrier (BTB) was reestablished after a minimum of 7 days, indicating that the existence of the blood-testis barrier is not dependent on specific gonadotropin supply but on the developmental stage of the seminiferous epithelium. Sham-operated animals showed increased cell and nucleus area of Leydig cells in comparison to photostimulated animals. After testicular involution as well as after LH or FSH treatment there were no significant morphological differences between hypophysectomized and photoinhibited animals in respect to the documented ultrastructural and morphometrical characteristics.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Sertoli cell nuclear changes in human testicular biopsies as revealed by three dimensional reconstruction.

Serial semithin sections of human testicular biopsy material were used for three-dimensional reconstruction in order to obtain information about Sertoli cell nuclei in normal and pathologically altered seminiferous epithelia. The three dimensional reconstruction program is based on the triangulation of image point series. It includes a calculation modus for determining surfaces and an approximation formula for the estimation of volumes. Nuclei from the following specimens were reconstructed and for each the volume (v), surface (s), and a quotient (v/s), which is regarded as a marker for the degree of membrane infoldings, were calculated as follows: (1) For normal spermatogenesis (stage 1, 2, 3, 5; n = 18) v = 409.7 +/- 33.0 microns 3, s = 429.6 +/- 40.5 microns 2, v/s = 0.96 +/- 0.05.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Round spermatids show normal testis-specific H1t but reduced cAMP-responsive element modulator and transition protein 1 expression in men with round-spermatid maturation arrest.

During spermiogenesis, histones are replaced by transition proteins, which in turn are replaced by protamines. The TNP1 gene-encoding TP1 (transition protein 1) protein contains a cAMP-responsive element (CRE) that serves as binding site for the CRE modulator (CREM). To gain further insight into the complex regulation of nucleoprotein exchanges in haploid spermatids and its potential role for spermatogenic impairment, we studied the gene expression of testis-specific histone H1t, CREM, and TNP1 in testicular biopsies from men with normal spermatogenesis (n = 20) and with round spermatid maturation arrest (n = 16). During normal spermatogenesis, H1t messenger RNA (mRNA) was present in 86.2%+/-8.7% of pachytene spermatocytes (stages III-V), whereas H1t protein was synthesized in 83.5%+/-13.0% of pachytene spermatocytes (stages III-V) and persisted in 95.2%+/-3.1% of spermatids (steps 1-5). CREM mRNA was detectable in 74.2%+/-9.4% of pachytene spermatocytes (stages IV-V) and in 78.7%+/-10.0% of spermatids (steps 1-3). CREM protein was synthesized in 81.2%+/-14.2% of spermatids (steps 1-3). TNP1 mRNA was present in 80.0%+/-13.5% of spermatids (steps 2-4), whereas TP1 protein was synthesized in 89.7%+/-5.3% of spermatids (steps 3-4). In men with round spermatid maturation arrest, spermatids only develop to step 3 of differentiation. These spermatids were devoid of both CREM and TP1 but did contain H1t. These results indicate that TP1 is likely to be an important parameter in the histone-to-protamine exchange and in the initiation of spermatid elongation. CREM is involved in the regulation of TNP1 gene expression and consequently plays a vital role in the correct differentiation step from round spermatids to mature spermatozoa.

Chromosomal Proteins, Non-Histone↗
PubMedDate not supplied

Chondroid tumors arising from the meninges--report of 2 cases and review of the literature.

Chondroid tumors are rare intracranial tumors usually arising from the base of the skull. We present 2 cases of intracranial cartilaginous tumors with unusual location. In case 1, a 19-year-old woman, a chondroma of the falx cerebri with extensive secondary ossification was diagnosed. In case 2, a 30-year-old woman, a low-grade chondrosarcoma was resected from the right frontal lobe. Both patients showed an uneventful clinical course without evidence of disease 4.5 and 6 years after total extirpation. Our cases show that chondromas and low-grade chondrosarcomas of the dura and meninges usually occur in young adults with a good prognosis after complete extirpation.

Adult↗
PubMedDate not supplied

Influence of long and short photoperiods on the morphology and androgen receptor levels of the epididymis and the ductus deferens of Phodopus sungorus.

The photoperiodic influence (LD 16:8 long photoperiod, LD 8:16 short photoperiod) on the morphology and the androgen receptor level of the epididymis and the ductus deferens of Phodopus sungorus was investigated. Under short day-conditions, the wet weight of the epididymis is reduced to 5-6%, the diameter of the epididymal duct and of its lumen are reduced, the height of the epithelium and the thickness of the smooth muscle layer are increased. Number and size of epithelial and smooth muscle cells are not changed, no atrophy of the smooth muscle cells is found. The loss in wet weight during short photoperiods is discussed in relation to the loss of stored sperm and luminal fluid. The wet weight of the ductus deferens is decreased to about 30% at short photoperiods, the total length of the organ, its diameter and the luminal diameter are decreased. The height of the epithelium is slightly, and the thickness of the smooth muscle layer is strongly, reduced, the latter due to an enormous atrophy of the smooth muscle cells. The androgen receptor content of the epididymis (per pair of organs) is reduced to about 5%, that of the ductus deferens to about 10% of the values found at long photoperiods, indicating a significant loss of androgen receptors with low circulating androgen levels.

Animals↗
PubMedDate not supplied

Primary T-cell lymphoma of the central nervous system.

A series of 6 patients with primary T-cell lymphomas of the central nervous system (PTCLCNS) is presented. The clinical, histological and immunohistological findings are shown. The lesions were infratentorial in the 34% and sopratentorial in the 66% of the cases. Of the 5 cases with an available follow-up only one died in the first year after diagnosis and one is alive and well after 42 months. These data agree with those of others series of PTCLCNS in the literature. In conclusion our data and those of the literature suggest that immunophenotyping should routinely be carried in primary non-Hodgkin's lymphomas of the CNS (PNHLCNS), because the T-cell forms run a more favourable course than the B-cell varieties.

Adult↗
PubMedDate not supplied

Effect of erythropoietin treatment on tissue oxygenation in patients with severe transfusion dependent renal anaemia.

OBJECTIVES: Severe renal anaemia can now be effectively treated with recombinant human erythropoietin (rhEpo). To evaluate muscle tissue oxygenation in patients with severe renal anaemia and the effects of an rhEpo treatment, muscle tissue oxygen tensions were measured in 9 patients suffering from end stage renal disease with severe renal anaemia before and during rhEpo treatment. METHODS: Muscle tissue oxygen pressure (method according to Ehrly and Schroeder), transcutaneous oxygen pressure (tcpO2) (Radiometer, Copenhagen), haematocrit (micro haematocrit method), plasma viscosity (Ostwald capillary viscometer) and erythrocyte aggregation (method according to Ehrly and Schmitt) were determined before as well as 4, 8, and 24 weeks after onset of treatment with 80 U/kg body weight 3 times per week. RESULTS: Muscle tissue pO2 values before treatment were markedly diminished when compared with normals and showed a marked increase into the normal range parallel to the increase in haematocrit. tcpO2 values were in the upper normal range before treatment and did not show significant changes during treatment. Erythrocyte aggregation and plasma viscosity did also not show significant changes. CONCLUSION: During rhEpo treatment a marked increase of muscle tissue pO2 can be found. This increase may be one of the mechanisms responsible for the improved well being and physical exercise tolerance in these patients due to erythropoietin treatment.

Adult↗
PubMedDate not supplied

Metastasizing extraneural tumors along the CSF pathway.

Dissemination of metastases from primarily extraneural tumors with the cerebrospinal fluid (CSF) is rare and most often seen in association with a leptomeningeal involvement. Here we present 2 cases of bronchogenic and 1 case of prostata carcinoma with multiple CSF metastases within the entire cerebral ventricles and the spinal canal.

Aged↗