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Biomedical subjects

V Covelli

Publications and source records attributed to V Covelli.

120 records · Page 7Linked to original sources
PubMedDate not supplied

Electron microscopic observations on T and B lymphocytes from spleens of syngeneic radiation chimaeras.

The ultrastructure of T and B lymphocytes has been examined in long-term syngeneic chimaeras and age-control mice. Spleen cell suspensions from these mice were passed through glass wool columns to obtain pure lymphocyte populations. These cells were then separated into T and B lymphocytes by nylon wool columns, and their purity was tested by cytotoxicity assays with anti-phi serum. Electron microscopic observations on such separated T and B lymphocytes did not reveal morphological differences except when the cells were fully differentiated, either as mature (T2) cells or plasmacells. In particular, T2 cells showed a very high cytoplasmic density, attributable to the presence of a larger number of microfilaments with respect to immature (T1) cells. In long-term chimaeras a significantly larger number of T2 cells was found as compared to age-control mice, and this morphological observation is correlated with the differences in immune reactivity and leukemia incidence previously described in these mice.

Age Factors↗
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Triazolobenzodiazepines exert immunopotentiating activities on normal human peripheral blood lymphocytes.

Previous studies have demonstrated that benzodiazepines (BDZ) (e.g. diazepam) inhibit immune responsiveness. Since these drugs are largely used in psychiatric patients it is of great importance to verify the existence of different types of BDZ, which are not suppressive for the immune system. In this framework, our results indicate that alprazolam and triazolam, two triazolo-BDZ, do not modify in vitro phagocytosis and killing exerted by normal human polimorphonuclear cells and monocytes. On the contrary, they significantly enhance T lymphocyte-dependent antibacterial activity in normal donors. These data support the concept that triazolo-BDZ and, in particular, alprazolam may represent more appropriate drugs for the treatment of psychiatric patients (e.g. patients with phobic disorders and/or migraine) who display immunodeficits.

Adjuvants, Immunologic↗
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In vivo administration of propranolol decreases exaggerated amounts of serum TNF-alpha in patients with migraine without aura. Possible mechanism of action.

Patients with migraine without aura (MWA) display elevated amounts of Tumor Necrosis Factor (TNF)-alpha in their sera. In this study in 18 patients with MWA the in vivo effect of propranolol, a beta blocker agent, was evaluated with regard to the TNF serum levels before and after treatment. Results show that in 9 out 11 patients exaggerated serum concentrations of TNF reverted to normality after three months of therapy. Some hypotheses on the mechanisms of action of propranolol in terms of modulation of the immune response are formulated.

Adult↗
PubMedDate not supplied

Brain tumor death risk in mental patients.

Several investigators have previously reported a low cancer mortality in mental patients. They hypothesized there were possibilities of actual exclusion between cancer and psychosis. On the other hand, some Authors warned that the reported association between psychiatric illness and cancer death might vary, depending on the used statistical methods. To clarify this problem, we have examined the incidence of deaths caused by malignant neoplasm, particularly from brain tumor, in the chronic patients of Bisceglie Psychiatric Hospital, evaluating either absolute or relative mortality rate analysis. Our results seem to suggest an increased absolute mortality from malignant brain tumor in mental patients.

Adult↗
PubMedDate not supplied

Neuropeptides with immunoregulatory functions: current status of investigations.

Neuropeptides (NP) from the central nervous system and the peripheral nervous system play a modulating role in the immune system. In principle, all immunological functions are influenced by NP either in terms of nonspecific immunity or cellular immunity. In the present review, some aspects of this interaction are summarized, namely the existence of receptors for NP on immune cells and the production of NP by leukocytes. Finally, the pathogenetic role of NP in diseases and the future perspectives of neuroimmunology are outlined.

Animals↗
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Electronic pupillometry for investigating pupil reactivity to different exteroceptive stimuli: applications and limits.

Iris neuromuscular junction represents a site of reciprocal interactions of sympathetic and parasympathetic innervation and can be considered a useful tool to investigate both systems in physiological and pathological conditions. In this study 35 healthy subjects of different ages were examined by an infrared TV pupillometer to assess darkness and light adaptation, as well as pupillary response to light and to exteroceptive stimulation (RIII reflex). A progressive impairment of pupil adaptability to light stimuli with aging was also observed, while a significant correlation was found between the intensity of electrical stimulation of the sural nerve and the percent increase in pupil diameter. The evaluation of pupil responsiveness is considered for its possible applications in various neurological disorders.

Adaptation, Physiological↗
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Acute ethanol administration during pregnancy: effects on central dopaminergic transmission in rat offspring.

The present study investigated the effect of ethanol ingestion during pregnancy on central dopaminergic function in the nervous system of the offspring. Marked changes in striatum of both binding of 3H-spiperone and the concentrations of DOPAC were found in offspring particularly when an acute dose of ethanol was administered to pregnant dams on the fourth day of pregnancy, whereas changes in the binding of 3H-5HT in cortex were not seen. Interestingly, administration of ethanol from the fourth day to the end of gestation, or only on the 13th day, caused different effects or no effect, respectively. These data suggest that alterations of dopaminergic function may be markers of teratogenic effects of ethanol, and may be related to some of the clinical symptoms appearing in children affected by Fetal Alcohol Syndrome.

3,4-Dihydroxyphenylacetic Acid↗
PubMedDate not supplied

The antimigraine effect of ergotamine: a role for alpha-adrenergic blockade?

The hypothesis that alpha-adrenergic receptor blockade accounts for the ability of ergotamine to stop migraine attacks was tested, in migraine patients, in an experimental migraine model based on nitroderivative- induced attacks. In a preliminary single blind, placebo controlled study, thymoxamine, a prevalently post-synaptic alpha adrenergic receptor antagonist, was able to abort migraine attack in 9 out of 10 patients, as opposed to 2 out of 10 by placebo (p < 0.005 Fisher's exact test). In a subsequent randomized, crossover, placebo controlled double blind study, the ability of a selective alpha-1 adrenergic receptor agonist, methoxamine, to block ergotamine antimigraine effect was studied. In 26 patients migraine was induced in two separate tests and then ergotamine was administered once after methoxamine pretreatment and once after placebo; methoxamine was significantly more effective than placebo in blocking antimigraine effect of ergotamine (p = 0.0055 Fisher's exact test). These results support the hypothesis that ergotamine alpha-1 adrenolytic properties may account for its antimigraine effect suggesting that this action takes place outside the blood-brain barrier, since methoxamine can cross it very poorly. Ergotamine target structure could be the trigeminal innervation of the extracranial and/or dural vessels.

Adolescent↗
PubMedDate not supplied

Quantitative and qualitative modifications of lymphocyte subsets after sublingual administration of isosorbide dinitrate in migraineurs. Preliminary report.

In 22 migraine patients and 5 healthy controls an investigation has been performed on lymphocyte subsets in basal conditions and 90 minutes after sublingual isosorbide dinitrate (IDN) administration. In all patients the drug assumption induced a typical migraine attack with increase in all examined lymphocyte subsets with except of NK cells. A statistically significant increase (p < 0.05) in T lymphocyte subsets we found during the crisis, whereas in healthy controls neither a migraine attack nor any modification in lymphocyte subsets could be observed. These results seem to confirm the immune alteration we have previously found in migraineous patients and suggest the possible role of IDN-stimulated endothelium not only in vasodilatation but also in production of substances responsible of the observed immune modifications.

Administration, Sublingual↗
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[Immunogenetic factors in the onset of experimental tumors].

The influence of immunological and genetic factors on the appearance of experimental tumors has been studied in mice by means of bidirectional selection. We found that the incidence of lymphomas, solid tumors and chronic nephritis is greater in mice selected for low antibody response than in mice selected for high antibody response. These findings suggest that the genes that control the antibody response also regulate life-span and resistance to neoplastic and inflammatory diseases. Similarly, we are carrying out bidirectional selective breeding to obtain two lines of mice, one sensitive and one resistant to the induction of cutaneous papillomas by chemical carcinogens. The two lines differ notably in terms of both percent of incidence and tumor multiplicity. The results of this study demonstrate clearly that resistance and susceptibility to carcinogenesis are subject to polygenic control.

Animals↗