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M Titlbach

Publications and source records attributed to M Titlbach.

At least 37 records · Page 2Linked to original sources
PubMed1982

Optical diffraction analysis of crystalline inclusions in the rough endoplasmic reticulum of islet parenchymal cells of the hagfish, Myxine glutinosa.

Optical diffraction analysis was carried out on crystalline inclusions in the rough endoplasmic reticulum of the insulin and somatostatin cells in the islet organ of the hagfish. A striking difference in crystalline arrangement was observed between the inclusions of the insulin and somatostatin cells. The crystallographic arrangement of the inclusions observed in situ in the insulin cells differed from that previously found by means of X-ray diffraction analyses of hagfish insulin crystals formed in vitro.

Animals↗
PubMed1981

Light and electron microscopic study of crocodile islets of Langerhans.

The tissue of the islets of Langerhans was studied in Alligator mississippiensis and Caiman niger. The distribution of the insular tissue in the pancreas was described from the picture in the light microscope, together with the incidence of characteristic islets, which frequently surround the duct tress, and of scattered insular cells. Five types of endocrine cells, distinguishable by their staining properties and typical electron microscopic image, were described in the insular tissue. In addition to A-, B- and D-cells, others which very probably correspond to EC- and PP-cells are described. Mixed cells were also found. The pancreatic interstitial connective tissue contains large numbers of nerve fibre bundles; isolated nerve fibres may penetrate to the insular cells. At the site of contact of a nerve ending with an endocrine cell, characteristic thickening of the membranes is sometimes found.

Alligators and Crocodiles↗
PubMed1981

The carotid body of the pheasant (Phasianus colchicus L.). An electron microscopy study.

In the pheasant, the carotid body lies laterally to the common carotid artery, is partly surrounded by parathyroid tissue and is immediately adjacent to the ultimobranchial body. In some cases these tissues intermingle. The cellular component of the carotid body consists primarily of granular endocrine cells, which are arranged in islands and lie in immediate proximity to wide capillaries and nerve fibres. A quantitative evaluation of granule size frequencies in these main cells, which we divided into three types, showed, inter alia, that the types represented three stages of cell differentiation, type III being the most mature cells. Only this last, i.e. mature, type can be used for differentiation from the granular cells of the ultimobranchial body of the same species, from which they differ. In addition, the main carotid body cells are typically surrounded by sustentacular cells. Numerous contacts with the terminal parts of axons were found on the main cells.

Animals↗
PubMed1980

Electron-microscopical investigations on adenohypophyses in sand rats (Psammomys obesus) before manifestation of diabetes mellitus).

The experiments have been carried out on the adenohypophyses of 20 sand rats (6 so called protodiabetic, 6 diabetic animals and 8 animals as control group). Of those cell types known in hypophyses alpha-(STH-)cells, prolactin (LTH-)cells, beta-(FSH-) cells, gamma-(LH-)cells and delta-(TSH-)cells were shown to exist in the hypophyses of the control group. -- The size of the granula of these cell types in the sand rats also corresponds to the values known from other rodents. A reduction of granular density could be noticed in the alpha-cells of the so called protodiabetic group as well as in the prolactin cells. The Golgi apparatus is prominent, and the mitochondria have grown and multiplied. The other cell types show no peculiarities. Changes were also found in the alpha- and prolactin cells of the diabetic group: The granula are diminished very much (more in the prolactin cells than in the alpha-cells), the ergastoplasm is much increased and has dense colonies of ribosomes. The Golgi apparatus is highly developed. These experiments prove ultrastructural changes in the cell types of the adenohypophyses not only in the state of a mellitus-like syndrome in sand rats but also during adaptation to laboratory holding of these animals. It is suggested that during adaptation to laboratory holding in a state of pronounced increase of body weight and in the state of a mellitus-like syndrome in sand rats the alpha-cells of the adenohypophyses are stimulated as well as the prolactin cells.

Animals↗
PubMed1980

Fine structure of the ultimobranchial body of the pheasant (Phasianus colchicus L.).

The pheasant's ultimobranchial body is characterized by the presence, in the connective tissue stroma, of epithelial cells between which two types of granulated cells comprising the main part of the glandular portion of the body are formed. Type I is characterized chiefly by the presence of nonrounded electron-dense secretory granules measuring 65-240 nm in the cytoplasm and by a very well-developed Golgi apparatus. The cytoplasm of type II cells also contains dark secretory granules, but somewhat smaller (50-150 nm). This type is very frequently in close contact with specific and often branching tubular structures from whose cells microvilli project into the lumen. The dark cytoplasm of the cells lining these structures contains a relatively large number of mitochondria and dense bodies, but no secretory granules.

Animals↗
PubMed1979

[Occurrence of glycogen-deposites in acinar cells of pancreas in prediabetic sand rats (Psammomys obesus) (author's transl)].

The investigations were in 6 prediabetic and 8 normoglycemic sand rats carried out with a histochemical method (PAS-reaction). Glycogen is present in pancreatic acinar cells in various quantity. It is in the cytoplasm homogenously distributed. The PAS positive acini are near the islets of Langerhans localized, which have in their B cells also glycogen deposites. The phenomenon is by the vascularisation of the pancreas explained.

Animals↗
PubMed1979

Evidence of three cell types in the islets of Langerhans in sand rats (Psammomys obesus).

The islets of Langerhans of sand rats were examined light- and electron microscopically with respect to the presence of various cell types. Apart from A- and B-cells, already known in sand rats, the presence of the third type of cells was established in the islet organ. According to their topography, argyrophilia (Hellman and Hellerström technique) and electron microscopical appearance of their granules they should be considered as D-cells.

Animals↗
PubMed1978

Fine structure of crystalline inclusions in B-cells of the islets of Langerhans in the alligator.

The ultrastructure of crystalline beta granules of the islets of Langerhans in the alligator has been investigated. From optical diffraction analysis and serial sectioning, the existence of four distinct types of crystalline inclusions was established in ultrathin sections. The first type is the most frequent and is interpreted as a rhombohedron with a base, the ortho-hexagonal unit-cell edges being a equal to 18.9 nm, c equal to 23.0 nm. The second type of crystal (not observed in serial sections) is found compatible with a rhomb-dodecahedron which indexes on a cubic cell with a equal to 9.6 nm. The third type of crystal was assigned to dipyramids. Dipyramids are extremely rare, and only two diffraction patterns were obtained; their crystal system could not be determined. Prisms, which are second in abundance, represent the fourth type of crystal. Spacings as well as the symmetry differ from those of the above three crystal types and indicate a tetragonal cell with a equal to 4.2 nm, c equal to 14.2 nm. The data for the prismatic crystals are strikingly similar to those of proinsulin and may represent the first case of agreement between crystals (i) formed in vitro and studied by X-ray diffraction and (ii) those investigated in situ by electron microscopy.

Alligators and Crocodiles↗
PubMed1977

[Presence of biogenic amines in the Langerhans' islets of the sand rat (Psammomys obesus) (author's transl)].

The islets of Langerhans of sand rats (Psammomys obesus) have been investigated ultrahistochemical in order to demonstrate biogenic amines. It could be found that amine containing vesicles with a diameter of 600 to 700 nm from the type of catecholamine granules exist in A-cells as well as in B-cells. Further, 2 very rare cell types not containing specific hormone granules could be found. These cells contain particles, in one case similar to catecholamine granules and in the other case representing serotonine-like granules according to their electron optical properties. It can be stated that the sand-rat belongs to the species containing amines in A- and B-cells. Moreover they contain 2 amines simultaneously. The importance of the amines for the regulation of the hormone secretion of the islets of Langerhans is discussed and the connections to the diabetes mellitus are refered to.

Animals↗
PubMed1977

Light and electron microscopy observations in the thyroid gland of the pheasant (Phasianus colchicus L.).

In the summer, the pheasant thyroid presents as a relatively quiescent organ with reduced secretory activity; the follicular epithelium is very low and mostly of the pavement type, while the follicles are unwontedly large and contain an increased amount of colloid. The follicular cell cytoplasm contains numerous characteristic spherical vacuolar structures. In the winter, however, the thyroid displays remarkable reconstruction and raised activity of the follicular cells, which are much higher and columnar; the small follicles contain less colloid. Peculiar rod-like or fusiform structures, some measuring up to 6,5 microgram, were observed in the cytoplasm of the follicular cells of both hen and cock pheasants in November and March. At the beginning of the winter (November), specific dark cells with pycnotic nuclei, evidently in process of degeneration, appeared in the follicular epithelium. In March, specific granulated cells (probably parafollicular cells) were found sporadically in the immediate vicinity of the wall of subcapsular follicles in cock pheasant.

Animals↗