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Biomedical subjects

D Drenckhahn

Publications and source records attributed to D Drenckhahn.

At least 145 records · Page 8Linked to original sources
PubMed1980

Localization of myosin, actin, and tropomyosin in rat intestinal epithelium: immunohistochemical studies at the light and electron microscope levels.

Myosin, tropomyosin, and actin were localized in the epithelial cells of rat intestine by means of specific antibodies to chicken gizzard smooth muscle myosin, tropomyosin, and actin by immunohistochemical studies at both the light and electron microscope levels (unlabeled antibody enzyme technique). The pattern of antibody staining was the following (a) Anti-actin was associated with the microfilament bundles of the microvilli in their entire length, as well as with the microfilament network in the terminal web. (b) Anti-myosin was concentrated along the rootlets of the microvillar microfilament bundles and within the filamentous feltwork forming the terminal web. (c) Anti-tropomyosin showed a distribution similar to that of anti-myosin. In addition, the three antibodies also labeled the subplasmalemmal web underneath the cell membrane bordering on the basal lamina. Utilizing the above ultrastructural findings, we wish to propose a functional model of microvillar contraction.

Actins↗
PubMed1979

Freeze-fracture studies of cytoplasmic inclusions occurring in experimental lipidosis as induced by amphiphilic cationic drugs.

The ultrastructure of cytoplasmic inclusions, which characterize experimental lipidosis as induced by several amphiphilic cationic drugs, was studied by means of freeze-fracturing and thin-sectioning. Retinal and adrenal tissues of rats chronically treated with high oral doses of chlorphentermine were used. In thin sections the cytoplasmic inclusions, which were previously shown to represent lysosomes overloaded with polar lipids, exhibit lamellated or lattice-like internal patterns. The present freeze-fracture observations are interpreted as to indicate that the lamellated inclusions contain polar lipids in the lamellar phase, whereas those with lattice-like patterns contain polar lipids in a hexagonal phase.

Adrenal Glands↗
PubMed1979

Myosin and actin containing cells in the human postnatal thymus. Ultrastructural and immunohistochemical findings in normal thymus and in myasthenia gravis.

Samples of normal human thymus of different ages (4-63 years old) were studied by immunofluorescence microscopy (using antibodies to smooth muscle myosin, to actin from the chicken gizzard, and antibodies to myosin from human striated muscle) as well as by routine electron microscopy. Thymus tissue from myasthenia gravis patients was also investigated for comparative reasons. Epithelial cells reacted with anti-smooth, but not with anti-striated muscle myosin, whereas myoid cells reacted with antibodies to striated, but not to smooth muscle myosin. Both epithelial and myoid cells displayed a strong immunoreactivity with antiactin. Corresponding to this immunoreactivity, both cell types contained bundles of thin, actin-like filaments. Myoid cells occurred in the rounded and elongated variety, and they were a normal constituent of all thymuses investigated in this study. Ultrastructurally, this non-innervated, striated muscle-like cell type possessed bundles of thin and thick filaments as well as Z lines in a rather disorganized arrangement, resembling striated muscle after denervation or various other pathologic conditions. There were no overt differences in the number and structure of myoid cells between healthy and myasthenic patients.

Acetylcholine↗
PubMed1979

[Comparative and quantitative ultrastructural study of the olfactory organs of four strains of domestic pigeons].

1. By counting the axons per micron 2 on electronmicrographs of cross-sectioned olfactory nerves and multiplying this number by the area of the cross-sectioned nerves, the number of olfactory receptors was determined in 4 breeds of domestic pigeons including homing pigeons. 2. The total number of olfactory receptors varied between 3.0 and 7.4 . 10(6). It significantly depended on the body size of the pigeons. There was no evidence for differences in the number of olfactory receptors between the breeds independent of body size. 3. No differences in the relative size of the olfactory bulbs could be detected between the breeds. 4. The ultrastructure of the olfactory epithelium was basically similar to that of other birds. The covering mucus layer was revealed to be a secretion product of both the olfactory glands of Bowman and the olfactory supporting cells. No differences were observed in the ultrastructure of the olfactory region between the four breeds investigated.

Animals↗
PubMed1978

The myotendinous junction of the smooth feather muscles (mm. pennati). A light and electron microscopic study on a myoelastic system.

Smooth feather muscles (mm. pennati) consist of bundles of smooth muscle cells which are attached to the feather follicles by short elastic tendons. In addition, some muscle bundles are interrupted by elastic tendons. The elastic tendon is composed of longitudinally arranged elastic fibers which branch and wavy bundles of collagen fibrils. Smooth muscle cells of the muscle bundles are attached to each other by desmosome-like junctions and by fusion of the basal laminae. The cytoplasm of the muscle cells is characterized by conspicuous thick filaments and abundant thin and intermediate filaments. These are attached to band-like dense patches (dense bands) at the plasma membrane which are particularly broad at the tapering end of the muscle cell. The contact surface between smooth muscle cells and their elastic tendon is considerably increased (i) by deep finger-like invaginations and indentations located at the tapering muscle end, and (ii) by branching of the coarse elastic fibers into slender processes, which are attached to the richly folded surface of the muscle cell endings by peripheral microfibrils. This intimate interlocking closely resembles the myotendinous junctions in skeletal muscle. In addition to fibroblasts and fibrocytes, the myotendinous junction of the young growing chicks contains numerous so-called myofibroblasts, which are suggested to represent smooth muscle cells differentiating into fibroblasts of the developing tendon.

Animals↗
PubMed1978

Distribution of myosin and the glial fibrillary acidic protein (GFA protein) in rat spinal cord and in the human frontal cortex as revealed by immunofluorescence microscopy.

The glial fibrillary acidic (GFA) protein and myosin were localized in rat spinal cord and human frontal cortex using specific antibodies against GFA protein from human spinal cord and highly purified smooth myosin from chicken gizzard by means of an indirect immunofluorescence microscopical approach. A strong GFA protein and myosin immunoreactivity was found in astrocytes of the white and grey matter and in the external glial limitans membrane. The very fine branches of astrocytic processes stained with anti-GFA protein, but not with anti-myosin. Similar results were obtained with the human frontal cortex, where myosin antibodies failed to reveal the very fine branches of protoplasmic astrocytes. As a whole, staining with the GFA protein antiserum was more crisp than with the myosin antibody.

Animals↗
PubMed1978

Amiodarone-induced lipidosis-like alterations in ocular tissues of rats.

The antianginal drug amiodarone (an amphiphilic cationic compound) causes a keratopathy in humans. In the present investigation the cytologic effects of amiodarone on ocular tissues of rats were studied. Ultrastructural alterations, which are typical of human keratopathy and characteristic of drug-induced lipidosis, could be experimentally reproduced in rats by local application of amiodarone. Repeated oral administration of high drug doses induced lipidosis-like alterations in many ocular cell types, particularly in retinal pigment epithelium. It is concluded that amiodarone has the potency to induce generalized lipidosis in rats, as do several other previously investigated amphiphilic cationic drugs. It is tentatively suggested that amiodarone-induced corneal alterations in humans might equally be interpreted as part of a generalized lipidosis.

Amiodarone↗
PubMed1978

Anterior polar cataract and lysosomal alterations in the lens of rats treated with the amphiphilic lipidosis-inducing drugs chloroquine and chlorphentermine.

Chronic treatment of rats with the amphipilic drugs chloroquine and chlorphentermine caused prominent anterior polar cataracts in virtually all rats. The basic pathologic changes underlying these cataracts were: (a) degeneration of anterior polar and sutural endings of cortical lens cells and (b) multilayered proliferation and invasion of epithelial cells into the anterior polar cortex. Ultrastructurally cortical lens cells displayed various patterns of degeneration, finally undergoing complete liquification. Liquified lens substance was phagocytosed by invading epithelial cells. Cortical lens cells and epithelial cells contained numerous lipidosis-like (lamellated) inclusions, which possessed cytochemical acid phosphatase activity. The present drug-induced lenticular alterations are interpreted as the direct or indirect consequences of a drug-induced disturbance of polar lipid metabolism in the lens.

Acid Phosphatase↗
PubMed1978

Different myosins in myoid and entodermal reticular epithelial cells of the thymus. An immunocytochemical study using specific antibodies against striated and smooth muscle myosin.

A sensitive immunofluorescence microscopical technique employing specific antibodies against highly purified actin and (smooth muscle type) myosin from chicken gizzard and myosin from human striated muscle was used to localize these contractile proteins in the thymus of rat, guinea-pig, cat and chicken. Myoid cells were seen to react with antibodies to striated, but not to smooth muscle type myosin, whereas reticular epithelial cells contained smooth, but not striated type myosin. Actin immunoreactivity was found in both myoid and reticular epithelial cells.

Actins↗