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Biomedical subjects

S S Han

Publications and source records attributed to S S Han.

At least 109 records · Page 6Linked to original sources

Diagnosis of cranial asymmetries in cerebral arteriovenous malformations.

Nine of 29 patients with cerebral arteriovenous malformations exhibited abnormal cranial asymmetries on computed tomography (CT). Two of these patients showed no other abnormalities on their precontrast CT scans. Assessment of cranial asymmetry is recommended in all patients suspected of having an arteriovenous malformation.

Diagnosis, Differential↗

The localization of thiamine pyrophosphatase activity in the acinar cells of stimulated and non-stimulated sublingual glands of the rat.

The distribution of thiamine pyrophosphatase (TPPase) activity in the acinar cells of the rat sublingual gland has been studied at various stages of the secretory cycle following stimulated secretion. The rats were stimulated to secrete by an intraperitoneal injection of isoproterenol and pilocarpine. In non-stimulated glands, TPPase activity is detected mainly in 3--4 cisternae at the inner concave side of the Golgi complex and in some adjacent condensing vacuoles as in other cells. In the acinar cells 1 to 2 h after stimulation, however, reaction product for the same enzyme activity is detected in the cisternae at the outer aspect, as well as the inner aspect, of the Golgi complex and even in the cisternae of the endoplasmic reticulum (ER). About 4 h after stimulation, TPPase activity becomes concentrated in 3--4 cisternae at the inner concave side of the Golgi complex as in the acinar cells under non-stimulated conditions. Morphological observations of the acinar cells 1 to 2 h after the stimulation have indicated that the reorganization of the Golgi complex and ER is a major event which occurs at this stage. It is possible that this cellular event is related to the occurrence of TPPase activity in those sites which normally show negative reaction in non-stimulated state.

Animals↗

Cytochemical characterization of the myoepithelial cells in palatine glands.

Myoepithelial cells of rat and mouse palatine glands are similar in fine structural appearance to those of other exocrine glands and smooth muscle cells. Myoepithelial cells reveal fibrils, and vesicular structures comparable to pinocytic or surface vesicles of smooth muscle cells. Lanthanum-impregnated preparations of the gland reveal that many of these vesicle-like structures are, in fact, invaginations of the plasma membrane and are continuous with the extracellular space. Observations on glandular tissue incubated for the demonstration of ATPase and adenylate cyclase have indicated that a high level of activity of these two enzymes is localized in the plasma membrane of the myoepithelial cells facing the acinar cells, and in vesicular structures along this membrane. The possibility that these enzyme activities are related to contractility of myoepithelial cells is discussed.

Adenosine Triphosphatases↗

The cytochemical localization of adenyl cyclase activity in rat sublingual gland.

Adenyl cyclase activity in mucous acinar cells and serous demilune cells of the rat sublingual gland was localized cytochemically. After incubation with adenylyl-imidodiphosphate (AMP-PNP) as substrate, deposits of reaction product are found along the cell membranes bordering the secretory surfaces of serous demilune cells. These are the membranes which participate directly in secretion by fusing with the granule membranes. The granule membranes of the demilune cells do not reveal reaction product, but the membranes of the granules which are fused with and become part of the cell membrane do show deposits. Thus, it appears that the cell membranes which fuse with granule membranes during secretion are associated with a high level of adenyl cyclase activity. In support of this, the luminal membranes of the mucous acinar cells which do not fuse with granule membranes during secretion are not associated with detectable amounts of adenyl cyclase activity.

Adenylyl Cyclases↗

Effects of 5-fluorouracil on exocrine glands. III. Fine structure of Brunner's glands of rats.

Effects of a pyrimidine analogue, 5-fluorouracil (Fur), have been studied by electron microscopy and by electron microscopic cytochemical techniques. Previous studies have demonstrated that rats show serious gastrointestinal disturbances 5 days after 3 daily injections of FUR (50 mg/kg). The present investigation demonstrates that Brunner's glands under the same conditions suffer certain cytological changes involving the Golgi apparatus, where a notable reduction in the number of Golgi stacks is observed. The vacuolar components in the Golgi complex appear empty. Cytochemical localizations of uridine diphosphatase and thiamine pyrophosphatase activities, however, are normal. The reaction products are localized in the distal two or three lamellae of the Golgi stack and within the secretory granules nearby. In addition reaction products are present along the apical plasma membrane on the luminal side, suggesting a possible movement of these membranes from the Golgi stack, via secretory granules, to the apical plasma membrane.

Acid Phosphatase↗