Cortical granule exocytosis in sea urchin eggs is inhibited by drugs that alter intracellular calcium stores.

In sea urchin eggs fertilization is accompanied by cortical granule exocytosis, a secretory event thought to be initiated by release of intracellularly sequestered calcium. We have examined the effect of two drugs on this process: chlortetracycline (CTC), a known chelator of intracellular calcium, and 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), an antagonist of intracellular calcium release in both skeletal and smooth muscle. Preincubation of eggs for 10 min with either CTC or TMB-8 blocked sperm entry, inhibited the burst of 45Ca2+ efflux normally seen postinsemination, and prevented fertilization envelope elevation.

The effect of deferoxamine on bleomycin-induced lung fibrosis in the hamster.

Bleomycin is a commonly used antineoplastic compound that can produce a dose- and time-dependent pneumonitis and fibrosis in humans. The mechanism of bleomycin-induced fibrosis is not known. However, current data suggest that the production of oxygen radicals by way of a ferrous ion-molecular oxygen mechanism might be related to the pulmonary fibrosis.

Survey of immunoglobulin A protease activity among selected species of Ureaplasma and Mycoplasma: specificity for host immunoglobulin A.

Because immunoglobulin A (IgA) is the predominant immunoglobulin at mucosal surfaces, IgA proteases produced by pathogenic bacteria are considered potential virulence factors for organisms that cause disease or gain entry at mucous membranes. To determine the role of IgA protease in the pathogenicity of mycoplasmal disease, a variety of human and animal mycoplasma and ureaplasma species were examined for IgA protease activity with human, murine, porcine, and canine IgA. None of the mycoplasma species examined showed detectable IgA protease activity with any of the IgAs tested.

Subretinal strands: ultrastructural features.

This report describes the histologic and ultrastructural features of 13 subretinal strands removed during vitreous surgery for retinal detachment with proliferative vitreoretinopathy. On the surface of the subretinal strands, retinal pigment epithelial cells were found that maintained their cellular characteristics. Inside the strand were modified pigment epithelial cells, fibroblasts, fibrocytes, myofibroblasts, macrophages, basal lamina material, fibrin, and often large amounts of collagen.

Experimental corneal neovascularization: biomicroscopic, angiographic, and morphologic correlation.

Sequential slit-lamp examinations and fluorescein angiograms were performed on adult rabbits to define the morphological and functional maturation of new intracorneal vessels induced by chemical cautery. The vasoproliferation induced by this injury began as vascular sprouts from the preexisting pericorneal vessels and continued until there were well formed vascular loops carrying blood to and from the cautery site. Many vessels, particularly venules, then regressed.

Comparison of quick-frozen and chemically fixed sea-urchin eggs: structural evidence that cortical granule exocytosis is preceded by a local increase in membrane mobility.

Eggs of the purple sea-urchin, Strongylocentrotus purpuratus, were fertilized and fixed with 2% glutaraldehyde at various stages during cortical granule exocytosis. Fixation resulted in membrane blebs being formed precisely at the point of incipient granule fusion. These blebs pinched off to form the membranous vesicles frequently seen in exocytic pockets and in the perivitelline space.

Exocytosis in vitro: ultrastructure of the isolated sea urchin egg cortex as seen in platinum replicas.

Sea urchin egg cortices, isolated on polylysine-coated cover glasses by the method of V.D. Vacquier (1975, Dev.

Specific termination of in vitro transcription by calf thymus RNA polymerase III.

In vitro transcription of cleaved SV40 DNA with calf thymus RNA polymerase reveals a discrete transcript. The pattern of resistance to the inhibitor alpha-amanitin identifies the RNA as a product of RNA polymerase III transcription. The RNA is shown to initiate artificially near a DNA terminus created by cleavage and to terminate specifically near a cluster of 8 thymidine residues within the SV40 control region.

Pathogenesis of capsular opacification after extracapsular cataract extraction. An animal model.

Opacification of the posterior capsule is the most common post-operative complication of extracapsular cataract surgery. We studied the sequential changes in the posterior capsule of the aphakic cat and monkey after extracapsular surgery using light microscopy, scanning electron microscopy, and transmission electron microscopy. In the cat, but not the monkey, there was proliferation of a pigment-containing membrane arising from the iris root and ciliary body, and extending onto the residual lens capsule.

Radiographic assessment of acetabular cup orientation. A new design concept.

An acetabular cup with a 270 degree rim wire has been designed to assist in the radiographic assessment of acetabular cup orientation in total hip arthroplasty. A study was conducted analyzing the component in various positions of lateral opening and version with three different X-ray-beam centering positions. The 270 degree acetabular rim wire allowed for easy and accurate assessment of component orientation when the pelvis was level and the central ray of the X-ray beam was centered over the hip.

The role of corticosteroids in the regulation of myocardial Na, K-ATPase in normotensive and spontaneously hypertensive rats.

Sodium, potassium-dependent adenosine triphosphatase (ATPase) of the renal tubule is known to be dependent on both gluco- and mineralocorticoids. Recent evidence suggests that corticosteroids may modulate ATPase activity at extrarenal sites. The myocardium contains glucocorticoid receptors to which mineralocorticoids can also bind.

Competitive inhibition and attachment assays in cell cultures to detect pathogenic binding components of mycoplasmas: a review.

A microattachment assay for quantitating adherence of radiolabelled Mycoplasma pneumoniae to human WiDr cell culture monolayers is described. Preincubating the WiDr cell monolayers with a protein-rich extract of M. pneumoniae inhibited the subsequent attachment of radiolabelled organisms.

Scanning electron microscopy of vascular casts in experimental ocular vasoproliferation.

Scanning electron microscopy of vascular casts was used to investigate three experimental models of neovascularization. In each experimental situation, the casts provided a valuable three dimensional representation of the newly formed blood vessels and permitted subclassification of the vessels within normal and proliferating vascular networks. They defined also the predominant origin of new vessels from venules and capillaries, and enabled the evolution of proliferating vessels into arterioles and venules to be documented.

Increases in lung prolyl hydroxylase and superoxide dismutase activities during bleomycin-induced lung fibrosis in hamsters.

Intratracheal administration of bleomycin causes pulmonary fibrosis in hamsters. Using this model the activities of lung prolyl hydroxylase and superoxide dismutase and the accumulation of neutral salt soluble and insoluble collagens have been determined. One unit of bleomycin was injected intratracheally to hamsters, whereas control animals received an equivalent volume of sterile saline by the same route.

Intracellular or extracellular calcium can be used to trigger C5a-stimulated enzyme secretion from rabbit neutrophils.

The ability of C5a to stimulate lysosomal enzyme release and 45Ca2+ efflux from rabbit neutrophils was studied. C5a stimulated beta-glucuronidase release from cytochalasin B-treated neutrophils either in the presence or absence of extracellular calcium. Depletion of cell calcium by pretreatment with the calcium ionophore A23187 blocked both the ability of C5a to elicit enzyme release in the absence of extracellular calcium and its ability to stimulate 45Ca2+ efflux.

Comparison of occupational hearing losses among military engineers and their civilian counterparts.

A previous study (Chandler and Fletcher, J. Aud. Res.

Mycoplasma hominis- tissue cell interactions: a review with new observations on phenotypic and genotypic properties.

Strains of Mycoplasma hominis isolated from different tissues of patients with a variety of disease processes and from cell culture substrates show marked phenotypic and genotypic heterogeneity, as determined by their antigenic and isozyme properties and by [3H]DNA-DNA hybridization and DNA cleavage pattern analyses. Strains isolated from the same tissues (blood of postpartum patients or human urogenital tract or cell culture substrates) have very high genomic homology and form clusters of similar strains. Clusters of strains that colonize similar specialized urogenital tissues may initiate diseases that reflect damage to the particular tissue colonized.

Mycoplasma pneumoniae attachment to WiDr cell cultures: competitive inhibition assays.

Attachment of radiolabeled M. pneumoniae to human WiDr cell culture monolayers was dependent on the WiDr cell density and the concentration of M. pneumoniae.

FMLP-induced enzyme release from neutrophils: a role for intracellular calcium.

The ability of the chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (FMLP) to stimulate beta-glucuronidase release and 45Ca2+ release from rabbit neutrophils was studied. FMLP stimulated enzyme release from cytochalasin B-treated cells either in the presence or the absence of extracellular calcium. Depletion of cell calcium, by exposure to either ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid or the calcium ionophore A23187, blocked the ability of FMLP to stimulate enzyme release and 45Ca2+ release in the absence of extracellular calcium.

Morphometric estimates of infiltrative cellular changes during the development of bleomycin-induced pulmonary fibrosis in hamsters.

The sequence of cellular infiltration into interstitial lung tissue subsequent to intratracheal administration of bleomycin was examined in hamsters. Quantitation of lesions following bleomycin treatment showed a transient increase in the percentage of lung involved, which peaked at 21 days and decreased thereafter. Associated with these lesions was a significant increase in interstitial cell profile density at 21 and 28 days.

Persistent corneal edema in the congenital rubella syndrome.

Corneal edema occurring in the congenital rubella syndrome can result from coexistent glaucoma or develop in the absence of an elevated intraocular pressure. We examined a 36-week-old female infant with documented congenital rubella syndrome who had bilateral corneal stromal edema without attendant congenital glaucoma. Histopathologic examination of the cornea revealed absent Descemet's membrane, deep interstitial keratitis, stromal corneal swelling, and deranged, focally absent endothelial cells.