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Biomedical subjects

M Camatini

Publications and source records attributed to M Camatini.

47 records · Page 3Linked to original sources
PubMed1981

Morphological changes of Leydig cells in men with altered plasma testosterone and gonadotropin levels.

The ultrastructural features of Leydig cells in patients with high serum LH and low serum testosterone are described. The results are compared with the structure of Leydig cells in normal conditions and after treatment with human chorionic gonadotropin (hCG) according to data existing in the literature. The continuous overstimulation of Leydig cells by higher levels of LH apparently induces significant modifications in many of the morphological elements characteristic of these cells. However, these differences were not constantly present in the cases observed. The abundance and the large size of mitochondria were the only common characteristics in the patients studied.

Adult↗
PubMed1979

Ultrastructure of spermiogenesis in men with congenital absence of the vasa deferentia.

Spermiogenesis has been investigated in four cases of agenesia of vasa deferentia. During acrosome formation various anomalies gave rise to late spermatids with deformed heads. Chromatin condensation proceeded normally, but completion of this process appeared to be delayed. Redundant nuclear membranes frequently persisted at the basal region of the nuclei in mature spermatozoa, which occupied niches within Sertoli cells, as the tubules had no lumen. Flagellar structure was normal. These findings support the view that the altered local milieu and variations in acrosome formation may induce the observed anomalies.

Acrosome↗
PubMed1978

Ultrastructure of acrosomal malformations in men with obstructive azoospermia.

Testicular biopsies from ten infertile men with obstructive azoospermia were evaluated by light and electron microscopy. Light microscopic analysis revealed normal testicular pattern with active spermatogenesis and many spermatozoa. At ultrastructural level the majority of early spermatids presented acrosomal abnormalities that become evident during the approach of the acrosomal vesicle to the anterior pole of the nucleus, and in subsequent maturational stages; these spermatids continue their development until mature spermatozoa with malformed acrosomes. The type of malformation was very similar in all cases observed and was associated with the same type of seminiferous tubule pattern in patients with the same type of azoospermia. The abnormalities at acrosomal level were related to an abnormal differentiation rather than to degenerative changes. Acrosomal disturbance did not influence nucleus morphology or chromatin condensation.

Acrosome↗
PubMed1978

Testicular biopsy of secretory azoospermia: electron and light microscopic analysis.

The histological and ultrastructural features of testicular cells were examined in testes with secretory azoospermia in seven patients with germinal cell arrest, two with Sertoli-cell-only; and one with tubular hyalinization. Germinal cell arrest was characterized by the presence of spermatogonia AD, AP, B, and some primary spermatocytes: these cells had similar ultrastructural features typical of the adult normal testis. Sertoli cells contained large number of various lipid inclusions and lipofuscin bodies. The multilayered peritubular wall presented increased collagen fibers. The cytoplasm of Leydig cells was filled with dilated vesicles of smooth endoplasmic reticulum and precursors of Reinke crystalloids. A blockage in the seminiferous tubules occurred after puberty, when tubular components, peritubular wall and Leydig cells had reached maturity.

Adult↗
PubMedDate not supplied

Copper and zinc uptake and hsp70 expression in HepG2 cells.

The aim of this work is to study the accumulation in HepG2 cells of two essential metals with toxic potency and to analyse the induction of the heat shock protein 70 kDa (hsp70) consequent to metal exposure. Cu and Zn were the metals considered and were analysed both as single compounds and in combination in order to evidence synergic effects of the mixture. The use of HepG2 cells provided an in vitro system that retains morphological and metabolic properties and the expression of specific genes typical of liver parenchymal cells. Moreover, the hepatic cells represent a suitable model for their susceptibility to metal toxicity since liver, gastrointestinal tract and renal tubular cells are involved in the uptake, transport, detoxification and secretion of these compounds. The uptake of Cu and Zn followed a time-dependent accumulation when they were used separate. The combination of the two metals produced a higher accumulation of Zn. The stress protein hsp70 was expressed before the metals accumulated within the cells, as shown by the measures obtained with the ICP-AES technique. Moreover, the accumulation of hsp70 by a sublethal shock provided a protective mechanism against metal cytotoxicity.

Cell Survival↗
PubMedDate not supplied

Overexpression of HSP70 is induced by ionizing radiation in C3H 10T1/2 cells and protects from DNA damage.

Various kinds of stress such as heat, UV, gamma-rays and chemicals that cause DNA damage induce heat shock proteins (Hsps), and in particular Hsp70. The Hsps cytoprotective function is not fully understood, although these proteins act as molecular chaperones or modulators of intracellular levels of reactive oxygen species (ROS). Recently, Hsps have been proposed to play a significant role in DNA repair after UV or gamma-ray irradiation. Ionizing radiation targets DNA molecules either via direct interaction or via production of free radicals and ROS. When exposed to gamma-rays C3H 10T1/2 cells are radiosensitive, therefore we decided to use them to investigate Hsp induction after ionizing radiation and their protective role against DNA damage. Here we demonstrate the induction of Hsps by gamma-rays, and investigate the kinetics of expression after irradiation at different doses. We also show that Hsp70 overexpression acts as a radioprotective mechanism towards the first event of DNA damage and increases long term viability. A preliminary investigation on the cell cycle does not evidence a significant protective action of inducible Hsp70 on it.

Animals↗
PubMedDate not supplied

Different induction of metallothioneins and Hsp70 and presence of the membrane transporter ZnT-1 in HepG2 cells exposed to copper and zinc.

Eukaryotic cells respond to stressful environmental stimuli, such as toxic concentrations of heavy metals, by rapidly synthesising defence proteins: the metallothioneins (MT) and the heat shock protein 70 (Hsp70). In this study we have analysed how the human hepatoblastoma cell line HepG2 responds to exposure to excess copper (30 microg/ml) and zinc (50 microg/ml) for long exposure times (48 and 72 h). Accumulation of the two metals, as measured by ICP-AES, was time-dependent reaching a plateau after 72 h. HepG2 cells responded by dramatically increasing levels of MT during stress, mostly during zinc exposure. A time lag in Hsp70 induction was observed as the levels of this protein increased only after removal of the stress from culture medium (recovery) for 24 h, thus suggesting that the two defence mechanisms are not coordinated in a metal-induced stress response. Moreover in HepG2 cells, immunochemical and fluorescence techniques showed the presence and the localisation of the zinc membrane exporter ZnT-1 as a further mechanism of defence/homeostasis against zinc toxicity.

Cell Line, Tumor↗