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Biomedical subjects

S Govoni

Publications and source records attributed to S Govoni.

224 records · Page 13Linked to original sources
PubMedDate not supplied

Time-related asymmetric changes of brain microvessel beta-adrenergic receptors in the two hemispheres after carotid occlusion.

The effect of short term and long term ischemia induced by right carotid occlusion was studied on beta-adrenergic receptor function in rat cerebral microvessels. The results show a different time-dependent responsiveness of the two hemispheres to ischemia, with a pronounced and more persistent decrease in the number of capillary beta-receptors in the left side of the brain. The data suggest the existence of asymmetries in the control of brain microvasculature which may mediate the different time-course of beta-receptor changes in response to ischemia.

Animals↗
PubMedDate not supplied

[The use of 1,1,1-trichloroethane (methylchloroform) in industrial operations: the neurotoxicity risk].

1,1,1-Trichloroethane (1,1,1-TE) is a widely used organic solvent which is thought to be relatively safe. The present review is mainly focused on the neurotoxic effects of 1,1,1-TE. Concentrations above 350 ppm are considered capable of negatively conditioning the performance of the exposed person, in particular reaction time and manual abilities. Peripheral neuropathies have also been described. More recently the potential neurotoxicity of 1,1,1-TE has been underscored by animal studies investigating the effects of this substance in neurobehavioral tests and on neurochemical parameters. 1,1,1-TE alters the motor activity in small laboratory rodents. In fixed interval responding in mice, the effects of 1,1,1-TE are qualitatively similar to those of other volatile (ethanol) and non volatile (benzodiazepines and barbiturates) CNS depressants. In addition, in drug discrimination procedures 1,1,1-TE shares discriminative stimulus properties with barbiturates, toluene, halotane, and oxazepam indicating that this solvent has behavioral effects in common with central nervous system depressant drugs. From a neurochemical point of view long-term exposure to 1,1,1-TE induces astrogliosis in the cerebral cortex of gerbils as indicated by an increased concentration of glial fibrillary acidic protein. In addition low dose inhalation of 1,1,1-TE for 3 months decreases DNA concentrations in several brain regions of the gerbil. 1,1,1-TE affects also brain concentrations of cAMP and cGMP as well as calcium ion control, possibly through an action on voltage-dependent calcium channels. It has been also suggested that intermediate metabolites of 1,1,1-TE may give origin to condensation products with dopamine, ultimately impairing dopaminergic transmission. Some of the neurochemical effects of 1,1,1-TE are shared by other chlorinated organic solvents as well as by CNS depressants. The literature analyzed indicates that 1,1,1-TE may exert significant neurotoxic effects suggesting that more caution in its use is needed and that attention should be paid to the possibility of an additive effect of 1,1,1-TE and CNS depressants (ethanol, barbiturates, benzodiazepines and other volatile solvents) giving origin to severe neurotoxicity.

Animals↗
PubMedDate not supplied

Plasma prolactin concentrations in lead exposed workers.

Plasma Prolactin (Prl) Zinc protoporphyrin (Zpp) and blood lead concentrations (PbB) were measured in 76 exposed male workers. All of them were employed in small (not more than 30 persons) pewter factories and were randomly selected from those regularly controlled by the National Health Service, Occupational Health Unit of Brescia (USSL 41). Although all plasma Prl values were within the normal range, the mean value of the subgroup having Zpp and PbB higher than 40 micrograms/dl was significantly higher (+47%) than that observed in the group of workers having Zpp and PbB less than 40 micrograms/dl. The data indicate the possibility of a lead-induced Prl secretion dysfunction, probably mediated by a decrease in dopaminergic inhibitory control.

Adult↗
PubMedDate not supplied

[Toxicologic hazards at the endocrine level of heavy metals].

The effects of heavy metals (in particular Pb, Cd, Cr, Mn and Hg) on pituitary, thyroid, adrenal gland, pancreas and gonads are reviewed. The effect of these metals on the CNS centers regulating endocrine function is emphasized. On this time, the reviewed data stress the importance of studying the mechanisms of preclinical damage and the biological markers of it.

Adrenal Gland Diseases↗
PubMedDate not supplied

5-HT1A and D-2 receptor affinity of o-methoxyphenylpiperazine derivatives with terminal benzamide fragment on N-4 alkyl chain. 2.

The synthesis of some o-methoxyphenylpiperazines with a benzamide moiety on N-4 alkyl chain was accomplished and their affinity for dopamine and serotonin receptor subtypes was assayed by in vitro receptor binding. The results show that several derivatives had a good affinity both on D-2 and 5-HT1A receptors, the IC50s ranging from 10(-7) to 10(-8) M.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMedDate not supplied

Variations in the levels of the JAK/STAT and ShcA proteins in human brain tumors.

BACKGROUND: Recent demonstrations that the JAK/STAT and ShcA signalling proteins are abundant in the developing CNS at the stage of maximal cell proliferation prompted us to determine whether these proteins were expressed in various human brain tumors. MATERIALS AND METHODS: Using Western blot assay, we analyzed specimens from control peritumoral brain tissue, medulloblastomas, ependimomas, astrocytomas, anaplastic astrocytomas and glioblastomas. RESULTS: Our analyses revealed that Jak1 and Stat3 were consistently more elevated in low grade gliomas (LG) (tumors characterized by a more pronounced glial phenotype) as compared to high grade gliomas (HG) (less differentiated glial tumors). The other STAT proteins were equally expressed, while Stat1 was slightly higher in LG gliomas. Among the other tumors analyzed, medulloblastoma contained the highest level of Jak1 and Stat3, while ependymoma showed elevated levels of ShcA proteins. CONCLUSIONS: These differences may reflect differences in the biological characteristics of the various tumors and may provide insight for further mechanistic studies to investigate the importance of particular signal transduction pathways in CNS tumors.

Acute-Phase Proteins↗