Fine structure of cell types in an ameloblastoma

An unusually large and old ameloblastoma, which revealed a diverse histological appearance, was studied by light and electron microscopy. In the tumor, the epithelial component formed several patterns in the collagenous stroma. The epithelial islands, consisting of tall columnar cells surrounding the inner core of stellate cells, mimicked the cells of the inner enamel epithelium and stellate reticulum, respectively, of the normal enamel organ. The ultrastructural appearances of the columnar cells, however, were only similar to those which are seen in undifferentiated preameloblasts. Areas of squamous metaplasia were present, and these squamous cells were structurally similar to the cells at the base of the oral epithelium. Some epithelial cells containing numerous lipid granules and mitochondria formed a network of cords. The connective tissue stroma was made up of fibroblast-like cells which appear to be metabolically active. In addition, multinucleated giant cells were present in the connective tissue stroma near the epithelial component.

Cyclophosphamide-induced abnormalities in the incisors of the rat

A single injection of 75 mg/kg cyclophosphamide caused gross dental abnormalities in rats. Broken, malformed, overgrown, and "extra" incisors developed several weeks after drug treatment. Radioautographic investigations show no unusual features in the morphology or labeling with H3-thymidine in the odontogenic cells. The results suggest that the cytotoxic effect of the drug is a temporary one which induces a residual alteration of tooth growth.

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.

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.

Massive edema of the ovary

Ovarian edema is a newly recognized clinicopathologic entity. A case of massive ovarian edema is presented in which a huge abdominal mass was considered to be an ovarian cyst roentgenographically and clinically. However, ultrasound revealed the mass to be solid. Five previously reported cases in which ovarian edema simulated a fibroma are reviewed.

The cytochemical localization of adenylate cyclase activity in mucous and serous cells of the salivary gland

The present study was undertaken to localize adenylate cyclase activity in salivary glands by cytochemical means. For the study, serous parotid glands and mixed sublingual glands of the rat were used. Pieces of the fixed glands were incubated with adenosine triphosphate (ATP) or adenylyl-imidodiphosphate (AMP-PNP) as substrate: inorganic pyrophosphate or PNP liberated upon the action of adenylate cyclase on the substrates is precipitated by lead ions at their sites of production. In both glands, the reaction product was detected along the myoepithelial cell membranes in contact with secretory cells, indicating that a high level of adenylate cyclase activity occurs in association with these cell membranes. The association with a high level of the enzyme activity might be related to the contractile nature of myoepithelial cells which are supposed to aid secretory cells in discharging secretion products. A high level of adenylate cyclase activity was also detected associated with serous secretory cells (acinar cells of the parotid gland and demilune cells of the sublingual gland), but not with mucous secretory cells. In serous cells, deposits of reaction product were localized along the extracellular space of the apical cell membrane bordering the lumen. This is the portion of the cell membrane which fuses with the granule membranes during secretion. Since the granule membranes are not associated with a detectable level of adenylate cyclase activity, it appears that the enzyme activity becomes activated or associated with the granule membranes as they become part of the cell membrane by fusion. The association with a high level of adenylate cyclase activity appears to be related to the ability of the membrane to fuse with other membranes. It is likely, since the luminal membrane of mucous cells which does not fuse with mucous granule membranes during secretion is not associated with a detectable enzyme activity.

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.

Duodenotomy defect

Radiographic changes in the duodenum after duodenotomy are discussed. Two types are noted. One is a polypoid mass, the other is a convex deformity at the lateral wall of the descending duodenum. The radiographic findings are explained by the surgical technique used for duodenotomy.