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Biomedical subjects

G Spiga

Publications and source records attributed to G Spiga.

18 recordsLinked to original sources
PubMed1998

TrkA receptors delay C6-2B glioma cell growth in rat striatum.

Nerve growth factor (NGF) acts as an anti-mitogenic factor in C6-2B glioma cells stably expressing TrkA (C6trk+). To study the effect of TrkA on cell growth in vivo, we grafted mock and C6trk+ cells into the striatum of ACI nude rats. Thy 1.1 and p75NTR immunohistochemistry revealed that wild type C6-2B cells formed a tumor mass in the striatum by 14 days. In contrast, C6trk+ transplanted rats did not show the presence of a significant tumor mass until 71 days. Analysis of this tumor showed that expression of TrkA was retained, but the synthesis of NGF was abolished. Our data encourage the speculation that expression of TrkA in glioblastoma in vivo will attenuate tumor progression.

Animals↗
PubMed1997

Toward the development of strategies to prevent ischemic neuronal injury. In vitro studies.

Cerebellar granule cells in culture, which are extremely vulnerable to excitotoxin glutamate or N-methyl-D-aspartate (NMDA), were used to study mechanisms of neuronal cell death and protection. Paradoxically, pretreatment of these cells with subtoxic concentrations of NMDA markedly blocked the neurotoxicity resulting from subsequent exposure to glutamate or NMDA. The NMDA-mediated neuroprotection can be antagonized by pretreatment of these cells with protein synthesis inhibitors, suggesting an involvement of protein(s) with neuroprotectant properties, most likely neurotrophic factors. Because basic fibroblast growth factor (BFGF) is well known to prevent neuronal cell death following mechanical or chemical injury, we have tested whether NMDA increases the synthesis of bFGF in cerebellar granule cells. NMDA elicited a rapid and time-dependent increase in bFGF mRNA, suggesting that availability of this trophic factor may play a role in the NMDA-mediated neuroprotection.

Animals↗
PubMed1996

Glucocorticoids differentially increase nerve growth factor and basic fibroblast growth factor expression in the rat brain.

Adrenocorticotropin hormone (ACTH) and adrenal steroids may influence trophic processes operative in neuronal plasticity. Because nerve growth factor (NGF) and basic fibroblast growth factor (bFGF) participate in neuronal trophism, we have investigated whether adrenal steroids induce the expression of these two trophic factors in the rat brain. The systemic administration of dexamethasone (DEX) elicited a rapid (within 3 hr) and sustained accumulation of bFGF and NGF mRNA in the cerebral cortex and hippocampus. Regional studies showed that DEX increases bFGF but not NGF mRNA in the cerebellum, striatum, and hypothalamus. In situ hybridization studies revealed that DEX increases NGF mRNA in superficial layers of the cerebral cortex and in the dentate gyrus of the hippocampus, and bFGF mRNA throughout the brain, suggesting that DEX induces NGF mRNA in neurons and bFGF in glial cells. ACTH administered systemically elicited a temporal and regional induction in NGF and bFGF mRNA similar to that obtained with DEX. Increases in NGF and bFGF mRNAs were also observed after administration of corticosterone and, albeit to a lesser extent, aldosterone, suggesting that the pituitary-adrenocortical axis plays an important role in the regulation of NGF and bFGF expression in the brain. Our data suggest that NGF and bFGF represent a link by which the adrenal cortical system can exert trophic action on the CNS.

Adrenocorticotropic Hormone↗
PubMed1992

[Comparison of acceptance tests of 5 linear electron accelerators for radiotherapy].

The acceptance tests of five electron linear accelerators have been analyzed to compare their completeness, the standards specified by the manufacturers and the measured deviations. Involved tests were relative to geometrical and mechanical parameters, photon and electron beam characteristics, dose monitoring systems, treatment table and safety systems. The comparison of acceptance tests has shown a significant nonuniformity, also due to the absence of a specific legislation; anyway, the measured deviations generally appeared to be within internationally recommended values.

Particle Accelerators↗
PubMed1989

[Radiological study of the thorax. Evaluation of efficacy-efficiency of a large-field image intensifier in mass screening].

Chest X-ray is the most frequent examination in radiology and accounts for a considerable portion of total population radiation exposure, mostly in screening programs. The ideal radiographic system is the one providing the best image quality together with the lowest dose to the patient, at a low cost. In this paper the authors analyze the potentials of a new chest X-ray examination unit equipped with a large-screen image intensifier (TS 57-Siemens). Two-thousand subjects were examined with this unit. The technical aspects of everyday practice are analyzed from the radiologist's point of view, together with the dose to the patient, image quality, and costs.

Adult↗
PubMed1977

[Determination of the pneumoconiosis hazard in the cork industry].

The AA. have carried out an epidemiological investigation in order to control the prevalence of chronic respiratory diseases on a group of 385 people working in several cork industries in North Sardinia. At the same time an environmental investigation has been carried out. Standard questionnaire (CECA questionnaire) for chronic bronchitis and pulmonary emphysema, standard chest X-ray film, spyrographic investigation, ECG and sputum analysis for acid resistent bacteria have been used for epidemiological investigation. Environmental dust concentration and individual dust exposure, environmental concentration of sulphur oxides, nitrogen oxides, carbon mono- and dioxide, ammonia nad microclimatic conditions have been studied. Examination of medical data shows only a low degree of respiratory pathology in contrast with results of other authors, probably because of different methods used for epidemiological investigation and data interpretation and because of different environmental and working conditions.

Air Pollutants↗
PubMed1977

[Environmental dust in a plant for the production of polyvinyl chloride].

The results of an investigation on environmental dust concentration and individual dust exposure in a drying and sacking section of an "emulsion" and "suspension" PVC plant are reported; data on environmental concentration and individual dust exposure have been obtained by gravimetric techniques using similar personal and static dust samplers. Morphology and particle size distribution have been studied by electron microscopy on airborne dust specimens. Morphological analysis showed remarkable differences concerning shape and size between particles sampled in the "suspension" polymer and "emulsion" polymer sacking sections. Remarkably high mean values concerning dustness have been observed: 1.30 mg/m3 (min. 0.15; max. 18.4 mg/m3) for environmental concentration and 5.39 mg/m3 (min. 0.28; max. 45.6 mg/m3) for individual exposure.

Air Pollutants↗
PubMedDate not supplied

Biological activity of interleukin-10 in the central nervous system.

Cytokines play a crucial role as mediators of inflammation. Astrocytes and microglia are the two major glial cells involved in the central nervous system immune responses. In this study we examined the effects of interleukin-10 (IL-10), one of the naturally occurring inhibitory cytokines, on different types of glial cells in culture such as rat astrocytes, hamster microglia and C6-2B glioma cells. Phosphorylation of signal transducers and activators of transcription (STAT) proteins was used as a marker for IL-10 activity. Within minutes, IL-10 elicited a strong and weak increase in STAT3 and STAT1 phosphorylation, respectively, in human T lymphocytes, suggesting that STAT3 is a main IL-10 signaling event in these cells. In contrast, IL-10 failed to induce STAT3 in glial cells, but elicited a weak increase in STAT1 phosphorylation in microglia and C6-2B glioma cells only, suggesting that in some glial cell population(s) IL-10 may produce cellular responses via activation of the STAT1 pathway. Moreover, in C6-2B cells, IL-10 elicited a decrease in the level of basic fibroblast growth factor mRNA. A similar decrease was observed in adult rat hypothalamus, indicating that this cytokine may regulate glial production of trophic factors. Our data suggest that IL-10 may play a role in glial cell differentiation and proliferation.

Acute-Phase Proteins↗
PubMedDate not supplied

[The factor of magnification in mammography].

The last generation of mammographic equipment allows mammography to be performed with direct magnification techniques, thanks to such technical features as microfocus, high focus-film distance, high-power generators. The authors compared the diagnostic yield of two different equipment sets, with 1.4x and 2x magnification respectively, and verified the utility of magnification radiography. A significant reduction was obtained in questionable diagnoses (42 to 18) in a group of 63 patients, with no evidence of substantial differences in the diagnostic yield of the images obtained with different magnification ratios. An objective analysis of the system resolution power privileges 2x magnification ratio, which however implies an increase in the average dose to the breast. The use of faster recording systems reduces the dose by 50%, though maintaining good image quality.

Breast Neoplasms↗
PubMedDate not supplied

[A cancer marker study in patients with neoplastic pathology of the neck and head area].

Specific markers able to detect either the presence of tumours or to identify the histological type of tumour are not currently available. Previous work yields an inconsistent picture of actual effectiveness of oncological markers, we therefore carried out a study on the cancer patients in our clinic. The present paper considered five markers (CEA, SCC, ca 19-9, TPA and Ferritin) and tested their effectiveness in diagnosing and following patients with head and neck neoplasias. The study was carried out on 102 patients, divided into three groups: 59 had been histologically diagnosed cancer but had not received any treatment (first group), the remaining 43 who had been treated (second group). We have also monitored the first group of no treated patients six months after therapy (third group). Our results suggest that while no significant conclusions may be drawn from SCC and CA 19-9, we found interesting results concerning Ferritin. Indeed Ferritin values increased by 22% in the first group, by 26% in the second one and by 19% in the third one. CEA and TPA values increased in non treated patients only by 22% and 12% respectively while they did not alter in the treated ones and they altered by 10.5% and by 10% respectively six months after therapy. Although our data are still preliminary and speculative and further evidence is needed, we can infer that the stage of the cancer and the positive markers appear to be concluded. The correlation is even stronger when all the cases are considered, without introducing the statistical and epidemiological variables.

Adult↗