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Biomedical subjects

M Bergmann

Publications and source records attributed to M Bergmann.

At least 235 records · Page 13Linked to original sources
PubMed1987

Protein transport to the epididymal lumen.

Experiments were performed to clarify the debate over the entry of circulating proteins into the epididymal lumen by use of the marker horseradish peroxidase (HRP). Epididymal tubules from the caput epididymidis of the rat were immersed in medium TC 199 containing HRP (3.5 mg/ml) for 5 min to 3 h at 33 degrees C. Sections were examined for the presence of tracer within the epithelial cells by electron microscopy. From 5 min to 3 h, vesicles containing peroxidase reaction products were found throughout the cytoplasm of the principal cells. Vesicles occurred close to both the basal and apical membranes, and many were found opening into the interstitial space and lumen, depending on the length of incubation. By 5 min labelled vesicles were infrequently found in the apical part of the cells. Reaction product was observed in the epididymal lumen adhering to the microvilli from 30 min of incubation onwards. At all periods of incubation peroxidase was present at the base of the epithelium and between the cells, but it was never found within the tight junctional complexes, and no reaction deposits were found within epithelial cells of tubules incubated in the absence of peroxidase. It is concluded that large molecules leaving the capillaries may enter the epididymal lumen in the caput by means of fluid-phase endocytosis.

Animals↗
PubMed1987

Tracer permeability of rat cortical blood vessels during regional hypothermia.

Using lanthanum nitrate as a tracer, the permeability of rat cortical blood vessels was investigated during regional hypothermia of the cerebral cortex by electron microscopy. The concentration of K+ ions in the extracellular space of the cortex was determined using an ion-selective micro-electrode. Only at temperatures below about 7 degrees C was an extravasation of tracer observed in a number of cortical capillaries and arterioles, where some of the tight junctions became widened and permeable. In a few cases penetration of the tracer into vacuoles of phagocytosing pericytes or macrophages was found. The extravasation of the tracer could mainly be observed in vessels on and below the cortical surface, less often in deeper cortical parts. At the same degree of hypothermia, the K+ concentration in the extracellular space increased, reaching a maximal value of ca. 6 mmol/l at a depth of about 200 micron. As could be shown in one previous experiment, the K+ concentration reached normal values again after rewarming to 37 degrees C for 15 min, but an extravasation of the tracer was still observed. The role of the endothelial tight junctions and of the astrocytes together with the pericytes (or macrophages) is discussed regarding their importance for the effectiveness of the blood-brain barrier system.

Animals↗
PubMed1987

Development of the blood-testis barrier in the domestic fowl (Gallus domesticus).

The formation of the blood-testis barrier (BTB) in the domestic fowl was studied at the electronmicroscopic level employing lanthanum as a tracer. No effective barrier could be demonstrated in testes before puberty, although several components of the Sertoli junctional complex such as focal tight junctions and desmosomes were already existent. The time of onset of meiosis after hatching showed great individual variation and meiosis did not occur synchronously in the tubules of a given testis. An effective barrier could first be detected in tubules containing early spermatids, and in which spermatogonia and primary spermatocytes at the leptotene stage were still within the open compartment. Thus, barrier formation was correlated with the occurrence of haploid germ cells. Complete compartmentation of seminiferous tubules, leaving only spermatogonia within the open compartment, was attained in tubules containing elongated spermatids of the maturation phase. In these tubules, primary spermatocytes at the leptotene stage were situated in an intermediate compartment.

Animals↗
PubMed1987

[Niels Stensen (1638-1686)].

The paper reminds of the great Danish anatomist, geologist, and bishop Niels Stensen (1638-1686) whose 300th anniversary of his death was in 1986. In anatomy his name is linked especially with the parotideous duct (Ductus Stenonianus) which was discovered by him in 1660.

Anatomy↗
PubMed1986

[Epidemiology of hormone dependent malignant tumors--ovulation inhibitors and liver tumors].

Since the first descriptions of liver tumours associated with the intake of steroid contraceptives, the literature has presented an increasing number of case reports as well as epidemiological studies on the relationship between benign liver tumours and the utilization of these drugs. We report 11 benign cases and one malignant case of liver tumours in connection with the intake of these steroid preparations.

Adenoma↗
PubMed1986

[Caspar Bauhin (1560-1624)].

The paper describes the life and scientific work of Caspar Bauhin, whose 425th anniversary of his birth is in 1985. He is well-known in anatomy and botany and some species of plants are called after him. In anatomy his name is linked with the ileocaecal valve, though he apparently did not discover it. Especially Bauhin was engaged in improvement of anatomical and botanical nomenclature.

Anatomy↗
PubMed1985

[Our experiences with percutaneous litholapaxy].

Percutaneous litholapaxy is a non-invasive method in the surgery of kidney-stones. We prefer the one-step-proceeding--the punction, the dilatation and the intrarenal instrumentation in one session. With this method in 24 cases we have dislocated 9 pelvic-stones, 13 calix-stones and 3 upper ureteral stones which could not remove themselves. Postoperative 4 patients had small residual-stones, 2 of them removed spontaneously without colics still in time of the hospitalization. Thinking of the minimal morbidity and invasiveness we mean, we can recommend the percutaneous stone-removing to our patients with nephrolithiasis after an exact exploration in the future, too.

Adult↗
PubMed1985

Differential permeability of pineal capillaries to lanthanum ion in the rat (Rattus norvegicus), gerbil (Meriones unguiculatus) and golden hamster (Mesocricetus auratus).

Capillaries in the pineal gland of the rat (Rattus norvegicus), gerbil (Meriones unguiculatus) and golden hamster (Mesocricetus auratus) were investigated by means of electron-microscopical tracer studies using lanthanum. The tracer was administered together with the fixative solution by perfusion via the left cardiac ventricle. In the rat, endothelial junctions of fenestrated capillaries are permeable to lanthanum. In the gerbil the tracer does not leave the capillaries, which are of the non-fenestrated type throughout the organ. In the golden hamster the two portions of the pineal system have different types of capillaries. While in the superficial pineal fenestrated capillaries permeable to lanthanum predominate, the deep pineal possesses capillaries that are, without exception, devoid of fenestrations and impermeable to the tracer. It is suggested that differences in the structure of the capillaries are related to differences in the extent of a specialized contact of the pineal gland to the third ventricle.

Animals↗
PubMed1985

Meiosis and spermiogenesis in the testis of Salamandra salamandra (L.) (Amphibia, Urodela).

Meiosis and spermiogenesis in the fire salamander, Salamandra salamandra, take place in an intermediate zone of the testis between the cephal immature and the more caudal mature part. Primary spermatocytes in zytogene and pachytene are characterized by synaptonemal complexes, flattened vesicles at the periphery of the cytoplasm and mitochondria with dilated cristae. Mitochondria in primary spermatocytes during meiosis, in secondary spermatocytes and early spermatids are typically arranged beneath the plasmalemma. Secondary spermatocytes are provided with pro-acrosomal granules, nucleolus-like bodies and complexes of annulate lamellae. Cytoplasmic parts with numerous vesicles seem to become extruded from secondary spermatocytes and spermatids. In testicular lobules containing pachytene spermatocytes the normally fibroblast-like follicle cells transform into glandular Sertoli cells. Already after the second meiotic division of germ cells lobule boundary cells show morphological features of steroid hormone secreting cells.

Animals↗
PubMed1985

[Topography of the infratemporal fossa in the newborn infant].

We compared in our investigations the shape and extent of the infratemporal fossa in newborn, children, and adult specimen. By macroscopical preparation we watched the course of the branches of the mandibular nerve and the maxillary artery and their relations to the masticatory muscles. For identifying of arterial and venous blood vessels the external carotid artery was injected with black ink. In the newborn a fibrous membrane was found coating the internal aspect of the mandibular ramus. The membrane is absent in adults.

Blood Vessels↗
PubMed1985

[Stomach cancer survival rates].

The cumulative 5-year survival rates in the case material of the years 1979-1983 with endoscopically-histologically confirmed gastric carcinoma were compared to those of the 1974-1978 period, particularly with reference to operative therapy and the histological type of carcinoma. The percentage of curatively operated patients increased from 40.6 to 49.7%, the rate of non-operated patients fell from 42.5 to 22.4%. The histological evaluation revealed a rise in the percentage of the adenocarcinoma from 37.1 to 53.5%-while the percentage of the solid carcinoma decreased from 29.1 to 15.5%. Following curative therapy, the calculated cumulative 5-year survival rate rose from 35.6 to 51.8% in men, however, fell from 66.2 to 48.3% in women. Most recent investigations showed men with curatively operated adenocarcinoma to have the best survival rate (60.6%); in women, this is true of mixed-type carcinoma.

Adenocarcinoma↗
PubMed1984

[Ulcus ventriculi healing time--anamnestic and psychosocial data].

An age group of patients with endoscopically ascertained florid ventricular ulcer was asked with regard to the aspects own anamnesis and family anamnesis, social descent, social state, sparetime planning, alcohol consumption, nicotine consumption as well as use of analgesics. After the control of the course the patients were subdivided into such ones with healing of the ulcer within 12 weeks and such ones with retarded healing. As comparative groups served patients with duodenal ulcer and patients with functional gastropathy. As a result the family anamnesis does not bring any significant differences. Male patients with retardedly healing ventricular ulcer in 23% of the cases suffered from diabetes mellitus and/or hypertension, before the first appearance of the disease they more frequently performed a responsible activity and were more frequently on shift work team patients with a healing corresponding to time. Females with retarded healing of the ventricular ulcer have in a higher percentage family problems and significantly more frequently take analgesics than the comparative groups. A decreased adaptation of the patients with ventricular ulcer with retarded healing is discussed and they are compared with the patients with duodenal ulcer.

Adult↗
PubMed1984

[Accessory mandibular canals in the human].

Besides the persisting mandibular canal accessory ducts pass through the bony lower jaw in fetuses and children. 2 of the ducts are more constant than others. They are named according to the first authors canals of Serres and Robinson. By histological and macroscopical methods and by X-ray technique we studied these ducts during development in human fetuses and children and counted their occurrence in the adult.

Adolescent↗
PubMed1983

Observations on the blood-testis barrier in a frog and a salamander.

A blood-testis barrier has been demonstrated in a frog, Rana esculenta, and in a salamander, Salamandra salamandra, using lanthanum as an electron-dense marker during fixation. The tracer penetrates the interstices between somatic follicle or Sertoli cells and germ cells in regions of the testis containing spermatogonia and spermatocytes, up to the level of punctate tight junctions. The latter can be localized between the somatic cells that line seminiferous units containing spermatids and mature spermatozoa. The barrier thus appears to be established after meiosis in both species investigated, although spermatids of different developmental stages can be found in open compartments of the testis in S. salamandra.

Animals↗
PubMed1983

Postnatal formation of the blood-testis barrier in the rat with special reference to the initiation of meiosis.

Postnatal formation of the Blood-Testis Barrier (BTB) in the rat was studied by either fixation in hypertonic fixative or employing lanthanum tracer. After 15 days of age, meiosis has reached different stages of spermatogenesis in different zones of the seminiferous cords. Only in those parts where germ cells are in the pachytene stage of meiosis do Sertoli cells form an effective barrier or tight compartment. Between 16 and 19 days of age, final formation of the BTB, which is to be found in the adult rat testis, occurs by zygotene and then leptotene stages successively entering the tight compartment. Thus, formation of a BTB by Sertoli cells does not occur synchronously along the length of the seminiferous cord but in accordance with the stage of meiosis of the associated germ cells.

Age Factors↗