Natural history of papillary lesions of the urinary bladder in schistosomiasis.
Variable epithelial hyperplasia was observed in urinary bladder of nine capuchin monkeys (Cebus apella) when examined at cystotomy 94 to 164 weeks after infection with Schistosoma haematobium. These hosts were followed for 24 to 136 weeks postcystotomy to determine the status of bladder lesions in relation to duration of infection and to ascertain whether lesion samples removed at cystotomy reestablished themselves in autologous and heterologous transfers. There was involution of urothelial hyperplasia in eight of nine animals and no evidence for establishment of transplanted bladder lesions. (+info)
Recruitment of the retinoblastoma protein to c-Jun enhances transcription activity mediated through the AP-1 binding site.
The retinoblastoma susceptibility gene product (RB) is a transcriptional modulator. One of the targets for this modulator effect is the AP-1 binding site within the c-jun and collagenase promoters. The physical interactions between RB and c-Jun were demonstrated by co-immunoprecipitation of these two proteins using anti-c-Jun or anti-RB antisera, glutathione S-transferase affinity matrix binding assays in vitro, and electrophoretic mobility shift assays. The C-terminal site of the leucine zipper of c-Jun mediated the interaction with RB. Although the B-pocket domain of RB alone bound to c-Jun, a second c-Jun binding site in the RB was also suggested. Mammalian two-hybrid-based assay provided corroborative evidence that transactivation of gene expression by RB required the C-terminal region of c-Jun. We conclude that RB enhances transcription activity mediated through the AP-1 binding site. Adenovirus E1A or human papillomavirus E7 inhibits RB-mediated transcription activity. These data reveal that the interactions between these two distinct classes of oncoproteins RB and c-Jun may be involved in controlling cell growth and differentiation mediated by transcriptional regulation. (+info)
Marmoset species variation in the humoral antibody response: in vivo and in vitro studies.
A comparison of the in vivo and in vitro antibody response capabilities of two marmoset species, Saguinus fuscicollis and Saguinus oedipus oedipus, revealed the former to be superior in elaborating humoral antibody. In vivo challenges with Escherichia coli lipopolysaccharide (LPS) and Salmonella typhi flagella consistently yielded higher antibody titres in S. fuscicollis; indeed, with LPS antigen, multiple inoculations of S.o. oedipus marmosets led ultimately to a decrease in antibody formation, in contrast to the anamnestic response of S. fuscicollis. This species differential in immune competence was also suggested in the in vitro stimulation of peripheral blood leucocytes (PBL) and spleen cells with sheep red blood cells (RBC). None of 55 S.o. oedipus PBL cultures and 49 of 89 (55%) S. fuscicollis cultures responded to the test antigen. A similar differential in response to sheep RBC was noted with the spleen cells of each species, although this report contrasts the antibody-forming potential of two marmoset species, a comparison of the immunological response profile of marmosets to those of other laboratory animals challenged with similar antigens suggests these primates may be relatively incompetent. The possible relationship between the haemopoietic chimerism of marmosets and a diminished immune competence is discussed. (+info)
Variations in acute multifocal histoplasmic choroiditis in the primate.
Experimental histoplasmic choroiditis was produced in primates by intracarotid injections of living H. capsulatum organisms. The severity of the choroiditis varied with inoculum size, as well as with site of injection (common carotid vs. internal carotid artery). A reproducible model of histoplasmic choroiditis in primates was produced with an internal carotid injection of 5,000 to 10,000 organisms/lb. The clinical and histopathological course of this acute choroiditis over the first 30 days is presented. (+info)
Histologic analysis of photochemical lesions produced in rhesus retina by short-wave-length light.
The photopathology of retinal lesions produced by extended exposure (1000 sec) to low corneal power levels (62 microW) of blue light (441 nm) was investigated by light microscopy in 20 rhesus eyes over an interval ranging from 1 hr to 90 days after exposure. Results indicate a nonthermal type of photochemical lesion originating in the retinal pigment epithelium and leading to a histological response with hypopigmentation which requires 48 hr to appear. This type of lesion helps to explain solar retinitis and eclipse blindness and has significance for aging and degenerative changes in the retina. (+info)
Intercellular junctions in the ciliary epithelium.
The fine structure of the intercellular junctions in the ciliary epithelium of rhesus monkeys and rabbits was studied with conventional electron microscopy of thin-sectioned specimens and the freeze-fracturing technique. In the rhesus monkey, a zonula occludens, zonula adhaerens, gap junctions, and desmosomes interconnect the nonpigmented cells, whereas gap junctions, puncta adhaerentia, and desmosomes connect pigmented to nonpigmented cells, and pigmented cells to one another. In the rabbit, desmosomes are absent between nonpigmented cells, and substituted for by puncta adhaerentia. The zonula occludens between nonpigmented cells greatly varies in its complexity in different regions of the cell perimeter, and in places, it may consist of very few intramembrane strands; this suggests that the ciliary epithelium is relatively leaky to ions and small molecules. Gap junctions are ubiquitous in the ciliary epithelium and particularly numerous at the interface between pigmented and nonpigmented layers; this finding indicates that the cells of the ciliary epithelium are joined in a metabolic syncytium. All gap junctions are characterized by the crystalline configuration which is typical of the uncoupled state; furthermore, in specimens fixed by immersion, they may be caused by uncoupling and take place in the time interval elapsing between interruption of the blood supply and arrival of the fixative fluid. Puncta adhaerentia resemble zonulae adhaerentes in their structural details but are macular in shape instead of encompassing the cell perimeter in a beltlike fashion. In contrast with desmosomes, the intercellular cleft of puncta adhaerentia has an irregular width and contains opaque material, but this never gives rise to the central band typical of desmosomes. On the inner aspect of the junctional membranes, there is a layer of fluffy material but no plaque of insertion for a bundle of tonofilaments. Finally, puncta adhaerentia have no representation in the interior of the plasmalemma and are intimately associated with cytoplasmic microfilaments. They probably anchor to the plasmalemma the contractile apparatus of the ciliary epithelial cells. (+info)
Pigment epithelial windows and drusen: an animal model.
Aging rhesus monkeys, both controls and those undergoing long-term administration of investigational oral contraceptive steroids, developed widespread hyperfluorescent dots at the posterior pole. The dots were considered to represent drusen. Histologic (including electron microscopic) study showed the "drusen" in some of the animals to be almost exclusively pigment epithelial windows produced by a lipoidal degeneration of the pigment epithelial cells. The experiment provided a fortuitous model for direct correlation of clinical and histologic observations of myriad uniform, tiny, depigmented, hyperfluorescent, nonleaking spots at the level of the retinal pigment epithelium. (+info)
The fine structural organization of the cuneate nucleus in the monkey (Macaca fascicularis).
The fine structure of the cuneate nucleus of the monkey (Macaca fascicularis) has been studied. The neurons were classified into three groups according to their nuclear morphology, the arrangement of the rough endoplasmic reticulum (RER) and the appearance of the Golgi complexes. Group I neurons had a regular nucleus and contained abundant cytoplasm in which were found well-developed RER and Golgi complexes. Group II neurons had a slightly irregular nucleus and a variable arrangement of the RER and Golgi complexes. Group III neurons were characterized by a deeply indented nucleus, and scanty cytoplasm in which the cytoplasmic organelles were poorly developed. Group II neurons were the most commonly encountered while Group I neurons were the rarest. Axon terminals contained either round of flattened vesicles. Axon terminals and dendrites commonly formed synaptic complexes. In one type the axon terminal, containing round vesicles, formed the central element, which is presynaptic to the dendrites surrounding it; in addition it is postsynaptic to axon terminals containing flattened vesicles. In another type a large dendrite formed the central element which is postsynaptic to axon terminals containing round or flattened vesicles. (+info)