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Biomedical subjects

H M Dembitzer

Publications and source records attributed to H M Dembitzer.

29 records · Page 2Linked to original sources
PubMed1968

Digestion and the distribution of acid phosphatase in Blepharisma.

Suspensions of Blepharisma intermedium were fed latex particles for 5 min and then were separated from the particles by filtration. Samples were fixed at intervals after separation and incubated to demonstrate acid phosphatase activity. They were subsequently embedded and sectioned for electron microscopy. During formation of the food vacuole, the vacuolar membrane is acid phosphatase-negative. Within 5 min, dumbbell-shaped acid phosphatase-positive bodies, possibly derived from the the acid phosphatase-positive Golgi apparatus, apparently fuse with the food vacuole and render it acid phosphatase-positive. A larger type of acid phosphatase-positive, vacuolated body may also fuse with the food vacuole at later stages. At about 20 min after formation, acid phosphatase-positive secondary pinocytotic vesicles pinch off from the food vacuoles and approach a separate system of membrane-bounded spaces. By 1 hr after formation, the food vacuole becomes acid phosphatase-negative, and the undigested latex particles are voided into the membrane-bounded spaces. The membrane-bounded spaces are closely associated with the food vacuole at all stages of digestion and are generally acid phosphatase-negative. Within the membrane-bounded spaces, dense, pleomorphic, granular bodies are found, in which are embedded mitochondria, paraglycogen granules, membrane-limited acid phosphatase-containing structures, and Golgi apparatuses. The granular bodies may serve as vehicles for the transport of organelles through the extensive, ramifying membrane-bounded spaces.

Acid Phosphatase↗
PubMed1967

A structural analysis of the myelin sheath in the central nervous system.

The cerebral white matter of rats subjected to a variety of noxious experimental conditions was examined in the electron microscope. Several unusual configurations of the myelin sheath are identified in addition to the usual configuration. These variations include the presence of (a) formed organelles within the inner and outer loops, (b) isolated islands of cytoplasm in unfused portions of the major dense lines, (c) apparently unconnected cell processes between the sheath and the axon, and (d) concentric, double myelin sheaths. A generalized model of the myelin sheath based on a hypothetical unrolling of the sheath is described. It consists of a shovel-shaped myelin sheet surrounded by a continuous thickened rim of cytoplasm. Most of the unusual myelin configurations are explained as simple variations on this basic theme. With the help of this model, an explanation of the formation of the myelin sheath is offered. This explanation involves the concept that myelin formation can occur at all cytoplasmic areas adjacent to the myelin proper and that adjacent myelin lamellae can move in relation to each other.

Animals↗
PubMedDate not supplied

The fine structure of exfoliated cervical and vaginal cells.

In order to understand the means by which cellular aggregates were maintained in gynecologic samples, the fine structure of samples derived from a number of women of various ages was examined with special attention paid to the intercellular junctions. Most cells in the samples were squamous cells containing numerous intercellular fibrils and glycogen granules. Parabasal or intermediate cells were also seen as well as occasional endocervical cells. All of these cell types were often found as parts of aggregates and, while other cell junctions were present, desmosomes were the most prominent. It was concluded that desmosomes were probably responsible for maintaining the aggregated state of many of the cells found in gynecologic samples.

Adult↗
PubMedDate not supplied

The monodisperse cervical smear: quantitative analysis of cell dispersion and loss with enzymatic and chemical agents.

The proper utilization of flow-through instruments for the automatic detection of malignant cells in human cervical specimens requires that the cells be in the form of a monodisperse suspension. Information regarding the degree of cell dispersion and of cell loss is therefore of critical importance in the evaluation of any procedure used to render cervical specimens monodispe automatic detection of malignant cells in human cervical specimens requires that the cells be in the form of a monodisperse suspension. Information regarding the degree of cell dispersion and of cell loss is therefore of critical importance in the evaluation of any procedure used to render cervical specimens monodispe automatic detection of malignant cells in human cervical specimens requires that the cells be in the form of a monodisperse suspension. Information regarding the degree of cell dispersion and of cell loss is therefore of critical importance in the evaluation of any procedure used to render cervical specimens monodisperse. We have devised a simple method for the simultaneous assessment of these two parameters using smears prepared with the Perkin-Elmer Uni-Smear Spinner. Our quantitative evaluation indicates that none of the 15 enzymatic and chemical agents tested to disperse cervical specimens produced an adequate monodispersed cell suspension without unacceptable cell loss. Electron microscopic evidence is used to illustrate the deleterious effects of some of the agents employed.

Amylases↗