Histologic evidence for impaired growth control in diphenylhydantoin gingival overgrowth in man.

Fibroblast density and collagen content in non-inflamed gingiva from patients with gingival overgrowth due to sodium 5,5-diphenylhydantoinate therapy were measured and compared to normal tissue. Direct counting of fibroblast nuclei as well as stereologic point-counting precedures were performed using stained microtome sections. In no case were fibroblasts more numerous or collagen fibres more ubiquitous in DPH-enlarged gingiva. The mature, fibrous-type DPH gingival lesion represents neither hypertrophy, hyperplasia nor fibrosis, but is an example of uncontrolled growth of a connective tissue of apparently normal cell and fibre composition.     

Congenital hepatic artery aneurysm simulating pancreatic carcinoma

The authors report a case of a hepatic artery aneurysm that simulated a mass in the head of the pancreas. The correct diagnosis was made preoperatively based on several findings: curvilinear calcification within the mass on CT, a well-defined cystic collection on ultrasound, absence of biliary duct dilatation or jaundice, and presence of other aneurysms.     

Caries and periodontitis associated with an unerupted third molar

Radiographic, gross, and histologic evidence is provided to demonstrate the development of caries and periodontal disease over a 5-year period in an unerupted tooth. The authors speculate on the pathogenesis of these disease processes.     

Subchronic toxicology of diethystilbestrol in the mouse

This study evaluated the subchronic (14-day) toxicity of selected (0.2, 1.0, and 4.0 mg/kg) daily subcutaneous injections of diethylstilbestrol (DES) in female (C57B1/6 X C3H)F1 mice. Parameters observed included body and organ weights, gross organ morphology, histopathology, clinical chemistry, and hepatic microsomal enzyme activities. The liver, bone marrow, and thymus are major target organs for DES. Liver enlargement, with associated histopathological changes consistent with mild hepatitis, centrolobular necrosis, and sinusoidal changes were observed. Supporting the histological changes were alterations in serum enzyme levels and microsomal enzyme activity. Bone marrow changes included decreases in the number of cells as well as the number of colony forming units per gram stem cells. Toxicity to the thymus was evidenced by decreased thymic weights and lymphocyte depletion. The hepatic and thymic effects were observed at the lowest (0.2 mg/kg) dose. Although all parameters were not assessed for recovery, those that were evaluated returned to control levels by thirty days after treatment.     

Rod and cone disc shedding in the rhesus monkey retina: A quantitative study

Four Rhesus monkeys were maintained for several months on a daily lighting schedule of 12 hr light and 12 hr darkness (12L:12D). The animals were then fixed by intracardiac perfusion at 1 and 5 hr following the onset of light, and at 1 and 5 hr after the offset of light. The number of phagosomes/mm of retinal pigment epithelium (RPE) was counted in the light microscope for both foveal and extrafoveal locations. At extrafoveal sites, phagosomes within the RPE cell bodies and those within the ensheathing processes bordering cone outer segments were counted separately. Counts at foveal and extrafoveal locations suggest that the rate of disc shedding, and therefore the rate of membrane replacement, is probably less for foveal cones than it is for rods. The number of phagosomes above the rod tips 1 hr following light onset and their diminution several hours later suggests that an increase in rod shedding, similar to the “burst” of rod shedding reported for other species, also exists in the monkey retina. The number and location of phagosomes 5 hr after the offset of light indicates that there could be another phase of increased rod shedding somewhere around the middle of the dark period. Phagosome counts in the foveal RPE were highest 5 hr after light offset, however the counts at 1 and 5 hr following light onset were nearly as high. The number of RPE phagosomes at both foveal and extrafoveal locations was lowest 1 hr after light offset. Counts of phagosomes within the sheaths of extrafoveal cones showed that about 20% contained one or more phagosomes within their sheaths. Of those sheaths that did contain phagosomes, approximately 25% had multiple phagosomes. There appears to be a considerable period of time during which extrafoveal cone phagosomes remain within the ensheathing processes, moving from the cone tips toward the apical RPE surface. Rod and cone disc shedding in the monkey retina are probably cyclic processes—although the temporal pattern of shedding may be different than that reported for other species.