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Biomedical subjects

A Aoki

Publications and source records attributed to A Aoki.

261 records · Page 15Linked to original sources
PubMedDate not supplied

Elemental concentrations in hair of inhabitants of a cadmium-polluted area.

To investigate the present situation of inhabitants living in the cadmium-polluted area of Toyama Prefecture, 95 hair samples were analyzed instrumentally by the neutron activation method. The concentrations were compared with nonpolluted samples. The concentrations of Cd, Cu, Zn, and Cu/Zn in hair were compared with those in some reported organs. The values of Cu/Zn were significantly lower (p less than 0.001) in hair of both female groups, but only somewhat lower (p less than 0.05) in hair of the male group. Causes of these facts are discussed. Results obtained from principal component analysis are also mentioned.

Adolescent↗
PubMedDate not supplied

Behaviour of a somatotroph population under a growth hormone releasing peptide treatment.

In this investigation, we studied the effects of Momany peptide (GHRP-5), on somatotroph secretory activity. Acute and chronic administration of GHRP-5 provokes a significant release of growth hormone that can be closely correlated with ultrastructural changes in somatotroph populations. After 3,5 and 7 days of GHRP-5 treatment, two somatotroph cell subpopulations coexist. One of them has an enhanced secretory activity and the other presents a quiescent appearance. Therefore, pituitary growth hormone content was not affected in the first seven days of GHRP-5 treatment. After 14 days, there was a significant depletion of growth hormone pituitary content coincident with the highest levels of serum growth hormone. These results concur with the surge of a new hyperactive somatotroph subtype characterised by numerous immature secretory granules that are discharged bypassing the maturation step. Acute and chronic treatments caused no changes in somatotroph cell density, the area immunostained for growth hormone and the levels of total mRNA for transcription factor pit-1. The results of pituitary cell cultures incubated with specific blockers for different signalling pathways demonstrated an involvement of the phospholipase C-inositol phosphate system in GHRP-5 stimulated somatotroph secretion. GHRP-5 treatment enhanced significantly the release of growth hormone, thereby eliciting ultrastructural modifications in somatotrophs that can be correlated with an increased secretory activity devoid of cell density changes.

Animals↗
PubMedDate not supplied

Androgen-dependent synthesis/secretion of caltrin, calcium transport inhibitor protein of mammalian seminal vesicle.

Effects of androgen status on the synthesis and secretion of rat caltrin have been studied by three different procedures: a) immunocytochemistry in seminal vesicle tissues; b) polyacrylamide gel electrophoresis and Western immunostaining of seminal vesicle secretion; and c) evaluation of trypsin inhibitory activity of the seminal vesicle secretion. Rat caltrin has been immunolocalized in cells of the secretory epithelium, specifically in the electron-lucent halo of secretory granules which store and transport proteins to the lumen. No caltrin immunoreaction was detected 14 days postcastration, and the ultrastructure of the epithelial cells was markedly altered. SDS-PAGE and Western blotting of the seminal vesicle secretion revealed alterations in the protein pattern and loss of the caltrin-related immunoreactive bands. The 54-kDa caltrin-precursor protein and the 6.2-kDa active caltrin were absent. Trypsin inhibitory activity of the seminal secretion was reduced about 50% in castrated animals. Daily testosterone administration restored both the protein pattern and immunoreactivity of the seminal vesicle secretion, and, as expected, reversed the morphological alterations of the gland after 7 days of treatment. Trypsin--inhibitor effect of the secretion also returned to normal levels after fourteen days of testosterone administration. Data suggest that the synthesis and secretion of caltrin are testosterone-dependent processes.

Animals↗
PubMedDate not supplied

Effect of gossypol on trypomastigotes and amastigotes of Trypanosoma cruzi.

Bloodstream Trypanosoma cruzi trypomastigotes isolated from infected mice undergo reduction of motility and structural damages after 5 to 45 min exposure to gossypol at concentrations ranging from 5 to 50 microM. When 1% serum albumin is added to the incubation medium, no alterations of parasites are observed, even with 100 microM gossypol. Intracellular T. cruzi amastigotes in infected Vero cell cultures exposed to 5 microM gossypol for 2 h do not show changes. Incubation with 5 microM gossypol for 48 h produces complete disruption of host cells; however, the amastigotes they contain show only minor alterations. The observations indicate that, in protein-rich media, gossypol is complexed into associations which have no activity on the different forms of the T. cruzi biological cycle.

Animals↗
PubMedDate not supplied

Regeneration of olfactory mucosa in mice after inhalation exposure to perchloroethylene.

An experimental group of 20 male pure-bred mice was exposed to perchloroethylene gas at 300 ppm for 6 h daily for 5 days. Histopathological study of the nasal mucosa, particularly the olfactory mucosa, was performed sequentially 2 weeks to 3 months after exposure, to clarify the process of regeneration. The tissue damage due to perchloroethylene gas was more persistent in the nasal mucosa of the olfactory region than in the respiratory region. Two weeks after exposure, ciliated epithelial cells, as well as normal pseudostratified nonciliated columnar epithelium, began to appear in the area previously covered by olfactory epithelium and remained for up to 3 months after exposure. A basement membrane was present under the ciliated epithelium, suggesting a possible persistence of basal cells. The olfactory epithelium may thus be replaced by ciliated epithelium. The lamina propria of the olfactory mucosa, however, lost its normal structure with atrophy of the olfactory nerves and Bowman's glands.

Administration, Inhalation↗
PubMedDate not supplied

Electron microscopic immunolocalization of caltrin proteins in guinea pig seminal vesicles.

Caltrins, the small, basic proteins of the seminal vesicle secretion that inhibit calcium transport into epididymal spermatozoa, and consequently the onset of the acrosome reaction and the hyperactivated motility, were localized in the epithelial cells and the lumen of the seminal vesicles of the guinea pig by an immunocytochemical procedure and electron microscopy. Rabbit antisera against each protein (caltrin I or II), and goat anti-rabbit IgG antiserum labeled with colloidal gold were used to detect the caltrin immunoreaction. The subcellular distribution of the gold labeling was occasionally localized in the rough endoplasmic reticulum but mainly within big secretory vacuoles containing low electron-dense material, which are components of the Golgi complex known as condensing vacuoles. These are involved in the intracellular transport, storage, and discharge of secretory proteins. Gold-labeled material released to the lumen was also detected. There was no clear evidence that the discharge was mediated by an exocytotic process. Immunoreaction was observed neither in the electron-dense core nor in the electron-lucent halo of the typical secretory granules of the epithelial cells of the seminal vesicles. Using light microscope immunocytochemistry, intense positive immunoreactivity was detected in the material secreted to the lumen but not on the epithelial cell layer. Only those cells undergoing a degenerative process and showing a picnotic nucleus and condensed cytoplasmic matrix exhibited detectable immunoreaction when gold label and silver intensification were applied. The same distribution of the immunoprobes was obtained by electron or light microscopy when antiserum to either I or II was used. It would appear that the two caltrin proteins of the guinea pig are synthesized in the rough endoplasmic reticulum of the epithelial cells and transported quickly to the Golgi complex where the secretory vacuoles (condensing vacuoles) are formed. The proteins are transported by the secretory vacuoles to the apical ends of the cells to be discharged into the lumen.

Animals↗