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Biomedical subjects

G Ferraro

Publications and source records attributed to G Ferraro.

At least 73 records · Page 4Linked to original sources
PubMed1996

Effectiveness of octreotide in controlling fasting hypergastrinemia and related enterochromaffin-like cell growth.

The effects of long term (6-month), high (500-micrograms), once a day administration of octreotide on enterochromaffin-like (ECL) cell proliferation were evaluated in eight patients with hypergastrinemic atrophic gastritis at risk for the development of gastric carcinoids. Fasting gastrin levels were determined during treatment and up to 6 months after the end of treatment. Chromogranin A, hCG alpha, and somatostatin-immunostained cells were morphometrically evaluated in biopsy specimens of corpus mucosa taken before and after treatment. The results showed that gastrin levels significantly decreased from 950 to 238 ng/L (-74.9%; P < 0.01) at the end of treatment, a decrease that persisted 6 months after the end of treatment (450 ng/L; P < 0.05). The volume density of CgA cells (mostly ECL cells) decreased from 3.7% to 2.1% of the epithelial component (-43%; P < 0.014), that of hCG alpha-storing ECL cells decreased by 85% (P < 0.0007), and that of somatostatin-stained cells decreased by 74% (P < 0.04). No clinically significant side-effects were found. It is concluded that octreotide treatment as used in the present study is safe and effective in reducing hypergastrinemia and associated ECL cell changes in patients with atrophic gastritis. The decrease in D cells is consistent with the occurrence of somatostatin receptors and related autocrine regulation in these cells.

Adult↗
PubMed1995

Lateral habenula and hippocampal units: electrophysiological and iontophoretic study.

In previous works we studied, on cats, the effects of lateral habenula (LH) stimulation on hippocampal units. In particular, the results showed an excitation or an inhibition in relation to the stimulation frequency (0.5-3.0 Hz or 5.0-20 Hz, respectively). All the LH stimulation effects were antagonised by iontophoretic intrahippocampal application of methysergide (MS). In this series of experiments it was possible to demonstrate, on rats, that LH stimulation causes an excitatory effect in a major number of hippocampal units in relation to the frequency increase. The inhibitory effect by iontophoretic serotonine application and the reversible blockade of habenular modulation after iontophoretic methysergide administration on hippocampal units suggest, on rats, the involvement of raphe. Such hypothesis, with anatomical evidences demonstrating an excitatory projection between LH and raphe, was confirmed by data concerning the effects of intraraphal NMDA iontophoretic application on hippocampal units (NMDA application for 30 s = excitation; NMDA administration for 10-15 min = inhibition). All the results suggest an habenular modulation of hippocampus through the involvement of the raphe in the context of which an interneurone is inhibitory on the efferent serotonergic raphe-hippocampus projection. This hypothesis finds further support from MS blockade effect during intraraphal NMDA iontophoretic administration.

Analysis of Variance↗
PubMed1995

Electrophysiological and iontophoretic aspects of the habenular influence on hippocampal neurones.

In previous experimental studies, carried out on cats, we demonstrated that electrical stimulation of lateral habenula (LH) at 0.5-3.0 Hz or 5-20 Hz had a double effect (low frequency-excitation; high frequency-inhibition) on the spontaneous firing rate of single hippocampal neurones. Our results, in agreement with similar case studies, allowed us to hypothesise that in the habenular modulation of the hippocampus the raphe nucleus is probably involved. In fact, all the effects of LH stimulation were antagonised by the iontophoretic intrahippocampal application of methysergide. In the present series of experiments, performed on rats, it was possible to demonstrate that LH stimulation at 1-10 Hz causes an excitation of a progressively major number of hippocampal neurones depending upon the increase of frequency stimulation. The absence of habenulo-induced effects after a iontophoretic application of methysergide on single hippocampal units suggests the involvement of the raphe nucleus. Furthermore, in consideration of recent anatomical evidences demonstrating an excitatory projection between LH and raphe nucleus, intraraphal N-methyl-D-aspartate (NMDA) application, performed through a Hamilton microsyringe, induces an inhibitory effect. All the results suggest that in the raphe context it is possible to hypothesise the presence of an intrinsic interneurone, directly activated by the excitatory projection arising from the LH; this interneurone is likely inhibitory on the serotonergic raphe-hippocampus efferent neurone. This functional organization is responsible for the effect of LH stimulation at different frequencies as well as for the effects of intraraphal NMDA application.

Animals↗
PubMed1995

Isolated congenital complete heart block: longterm outcome of mothers, maternal antibody specificity and immunogenetic background.

OBJECTIVE: To assess the longterm outcome of mothers of children with isolated congenital complete heart block (CCHB), and the maternal specific immunoblot pattern and HLA antigens. METHODS: Fifteen mothers of 16 children with isolated CCHB were investigated; their followup extended up to 15.8 years on average after the index delivery. Anti-Ro and La antibodies were detected by counterimmunoelectrophoresis and ELISA; anti-Ro antibodies were studied by immunoblot. HLA typing was done using a microcytotoxicity test. RESULTS: One mother has systemic lupus erythematosus (SLE) before the index delivery. The other mothers developed only minor symptoms (arthralgia, dry eyes and photosensitivity) resembling primary Sjögren's syndrome more than classic lupus. All 15 mothers were anti-Ro and 9 were also anti-La positive, a mean of 12.5 years after the index delivery. Eight mothers reacted with the 52 kDa SSA(Ro) component, and 2 also with the 60 kDa SSA(Ro) component. The prevalence of the DR3 antigen and of the B44/DR5, DR3/DQ2 and A1/Cw7/B8/DR3/DQ2 haplotypes was significantly increased. CONCLUSION: The longterm outcome for the mothers of children with CCHB is more reassuring than generally assumed. All the mothers were anti-Ro positive by sensitive ELISA: Reactivity to the denaturated 52 kDa SSA(Ro) component seems characteristic of these mothers, who presented a particular immunogenetic background.

Adult↗
PubMed1994

Anticonvulsant activity of the noradrenergic locus coeruleus system: role of beta mediation.

Many experimental observations have demonstrated the modulatory role exerted by several neural structures and neurotransmitters on spontaneous and paroxysmal bioelectric activity of the hippocampus. Recently, the control exerted by locus coeruleus (LC) and its noradrenergic (NA) efferent pathway on different experimental models of epilepsy (e.g. cortical cobalt chronic epilepsy, amygdaloid and hippocampal kindling) was emphasised. On this basis, a series of experiments was performed to elucidate the functional role of LC-NA system on the hippocampal penicillin (PCN) focus and the type of adrenergic receptor involved. The experiments were carried out on 25 rats in which an epileptiform hippocampal focus was obtained through intrahippocampal PCN administration (100-200 I.U.). In these conditions, LC, ipsilateral to PCN hippocampal focus, was stimulated before and after intraperitoneal (i.p.) administration of a beta-adrenergic receptor antagonist propranolol (2 mg/kg). Results showed a significant reduction of hippocampal spiking frequency during LC stimulation; after i.p. propranolol injection, LC stimulation, at the same parameters, failed to induce any sort of modification of PCN hippocampal spiking frequency. Furthermore, intrahippocampal application of a beta-selective agonist 2-fluoro-noradrenaline (2-FNA) mimics the inhibitory effects of LC stimulation. All data suggest that the LC-NA system is able to induce a net reduction of hippocampal epileptiform focus and the inhibitory NA control involves the activation of adrenergic beta receptors.

Animals↗
PubMed1994

Bilateral reciprocal organisation in man: focus on IA interneurone.

The H reflex of flexor carpi radialis and radial-induced reciprocal inhibition were recorded in normal subjects during conditioning stimulation of the contralateral median or radial nerves. It was found that stimulation of the contralateral median nerve enhanced the degree of reciprocal inhibition exerted by the radial nerve on the median nerve, while contralateral radial nerve stimulation reduced the reciprocal inhibition exerted by the extensor on the flexor. In two subjects in which a pure extensor H reflex was recorded specular features were observed following contralateral median and radial stimulation. These findings are considered to be the electrophysiological manifestation of contralateral modulation of reciprocal inhibition, which is likely to act at the level of the IA interneurone.

Adult↗
PubMed1994

Locus coeruleus noradrenaline system and focal penicillin hippocampal epilepsy: neurophysiological study.

Previous experimental investigations have shown that several neuronal systems modulate the spontaneous and paroxysmal electric activity of the hippocampus. The locus coeruleus-noradrenaline (LC-NA) system exerts an inhibitory influence on several brain areas including the ipsilateral hippocampus. Selective destruction of the LC increases the susceptibility to epileptiform phenomena in different models of experimental epilepsy. Our experiments were conducted on 34 rats in which a steady epileptiform interictal activity of the hippocampus was obtained by means of intrahippocampal administration of penicillin. Electrical stimulation of LC caused a significant decrease of penicillin spiking of hippocampus. Stimulation sessions given 10-15 min after i.p. propranolol administration (2 mg/kg) failed to induce any significant modification in the hippocampal spiking frequency. Intrahippocampal injection of L-noradrenaline mimicked the inhibitory effect of LC electrical stimulation on hippocampus. Finally, intrahippocampal administration of isoproterenol HCl, a beta-adrenoceptor agonist, caused a significant decrease of hippocampal penicillin spiking; this effect was antagonised by i.p. propranolol administration. The experimental data show a modulating influence of the LC-NA system on penicillin focal hippocampal epilepsy that probably involves beta-adrenoceptors.

Animals↗
PubMed1992

Effects of pH on the binding of hematoporphyrin derivative to monolayer and bilayer membranes.

The effects of pH on the binding of hematoporphyrin derivative (HpD) to monolayer and bilayer membranes have been studied. Absorption spectra of HpD bound to phosphatidylcholine (PC) liposomes indicate that there is greater binding of HpD to lipid films at acidic, tumoricidal pH conditions than at normal tissue pH. These results were found to correlate with surface pressure measurements of monolayer films formed under similar conditions. Surface potential measurements in conjunction with surface pressure measurements from monolayer films suggest that at low pH (i.e. less than or equal to 6.6) porphyrin intercalates within the lipid film to reach relatively high concentrations, while at higher pH (i.e. greater than or equal to 7.4) the porphyrin preferably adsorbs to the lipid film at the monolayer/water interface.

Hematoporphyrin Derivative↗
PubMed1992

Evidence of a contralateral motor influence on reciprocal inhibition in man.

The role of contralateral movement on both H reflex and reciprocal inhibition was studied. In normal men H reflex was induced by median nerve stimulation. Reciprocal inhibition was achieved through stimulation of the antagonist radial nerve. On this basis the effects of contralateral arm movement were analyzed. Furthermore the putative influence of exteroceptive origin was also verified by means of digit stimulation. Results showed that contralateral arm movement did not affect H reflex amplitude; on the contrary, it was able to enhance reciprocal inhibition induced by extensors on flexors. Study of cutaneous afferents demonstrated that contralateral digit stimulation failed to elicit modifications on both H reflex and reciprocal inhibition. On the other hand, ipsilateral digit stimulation lowered H reflex amplitude and increased the degree of reciprocal inhibition. Experimental findings underline the possibility that an informational array reaches the contralateral IA interneuron: therefore a mutual (bilateral) interaction among IA interneurones may accordingly be hypothesised.

Adolescent↗
PubMed1992

Accumbens-caudate-septal circuit as a system for hippocampal regulation: involvement of a GABAergic neurotransmission.

Hippocampal-based epileptiform activity may reach the basal ganglia via the nucleus accumbens. Previous data suggested that caudate nucleus is able to influence hippocampal epilepsy, probably sending a projection to the septum. In order to test the hypothesis of a retrograde activation of accumbens-caudate pathway in hippocampal regulation, we electrically stimulated both caudate nucleus and nucleus accumbens and studied modifications of hippocampal EEG in the feline focal epilepsy model. We also performed bilateral electrolytic lesion of nucleus accumbens and repeated caudate stimulation. Results showed that nucleus accumbens stimulation was ineffective in modifying hippocampal epilepsy; on the contrary, caudate stimulation caused a statistically significant decrease of hippocampal spike frequency and amplitude. On the other hand, in accumbens-lesioned animals caudate activation consistently reduced hippocampal epilepsy to a significant degree. As the caudate nucleus influences hippocampal activity and the septum may constitute a relay station of this functional relation, a possibility was tested concerning a GABAergic mediation. To this end, after a stable caudate-induced effect was reached, an intraseptal microinjection of picrotoxin (GABA receptor antagonist) was made and caudate stimulation repeated at the same parameters. Such a study showed that after intraseptal picrotoxin, caudate stimulation failed to elicit any type of modification of hippocampal activity. Experimental findings support the notion that the striatal modulation on hippocampus is mediated by an anterograde rather than a retrograde pathway, and underline the possibility of a GABAergic caudate-septal influence.

Animals↗
PubMed1992

Ventriculoatrial shunt infection caused by Staphylococcus warneri: case report and review.

Staphylococcus warneri, a coagulase-negative species, is a rare cause of infection of cerebrospinal fluid (CSF) shunts. In one recently studied case of ventriculoatrial shunt infection, the repeated isolation of S. warneri (i.e., from all of six blood cultures and from a CSF sample obtained directly from the valve of the shunt) suggested that this organism can be clinically significant. Review of the literature clearly indicates that S. warneri is a rare but potentially dangerous pathogen in both immunocompetent and immunocompromised hosts with prosthetic devices. The removal of the infected shunt in association with systemic and local antibiotic administration probably constitutes the treatment of choice in such infections. Further experience is needed to determine the prevalence and the pathogenic significance of S. warneri and of the related organisms Staphylococcus epidermidis and Staphylococcus saprophyticus in patients with prosthetic devices.

Bacteremia↗
PubMed1992

Dihydroxy-carotenoid liposomes inhibit phototoxicity in Paramecium caudatum.

The phototoxic effects of hematoporphyrin derivative, using Paramecium caudatum as a model system, are significantly reduced in the presence of carotenoid-containing liposomes. Multilammelar large or small unilammelar vesicles, containing specific carotenoids, were effective in protecting the organism, whether administered exogenously in the bathing solution, or via incubation of paramecia in starved culture media containing carotenoid liposomes. The effectiveness of the carotenoids as inhibitors of phototoxic effects was found to depend on the mode of administration, with small unilammelar being more effective than multilammelar large vesicles for all carotenoids tested. Small unilammelar vesicles containing the dihydroxy-carotenoids zeaxanthin or astaxanthin afforded the greatest protection in both exogenous and endogenous studies. The results of this study suggest that carotenoid efficacy may be determined, in part, by the environment of the carotenoid molecules.

Animals↗
PubMed1992

Cerebrospinal fluid levels of IL-6 in patients with acute infections of the central nervous system.

Interleukin-6 (IL-6) activity was measured in the cerebrospinal fluid (CSF) of patients with acute bacterial or viral meningitis and in AIDS patients with various cerebral disorders. Increased levels of IL-6 were detected in the CSF of patients with bacterial meningitis. On the contrary, most of the samples from patients with viral meningitis (predominantly caused by mumps virus) had no detectable IL-6 activity in CSF. A moderate increase of IL-6 levels was detected in the CSF of AIDS patients with AIDS dementia complex (ADC), progressive multifocal leukoencephalopathy and cerebral toxoplasmosis. Moreover, higher levels of IL-6 were detected in the CSF of patients with cryptococcal meningitis. We conclude that the initial events of CSF inflammation in patients with acute viral meningitis are different from those in patients with acute bacterial meningitis, and the role of IL-6 is less critical to the process.

AIDS Dementia Complex↗
PubMed1992

Preliminary evaluation of immunoadjuvant activity of an orally administered glucan extracted from Candida albicans.

The immunoadjuvant activity of an orally administered glucan (Glucanil, Gluimmun) was investigated in mice. Glucan was extracted from Candida albicans ATCC 20955 and purified by an alkali-acid and detergent treatment. In this study the chronic intravenous infection with Candida albicans (treated or not with amphotericin B) or Staphylococcus aureus was the experimental model. Moreover the production of interleukin-2 was evaluated in treated animals. Oral treatment with glucan at 1 mg/mouse/day repeated doses, starting from 10 days before the experimental infection, significantly increased polymorphonuclear leukocytes and peripheral monocytes number. A significant increase in number and in vitro candidacidal activity was also observed for alveolar macrophages. The resistance towards systemic infection with Candida albicans or Staphylococcus aureus increased, significantly reducing the growth of microorganisms in the kidneys of infected animals. Glucan significantly increased the candidacidal spleen cells activity and synergized with amphotericin B chemotherapeutic action. Higher doses (eg. 2 or 5 mg/mouse) were not effective. A 10 days oral treatment with 1 mg/mouse/d significantly increased the interleukin-2 production. Toxicological studies showed that glucan is highly tolerated.

Adjuvants, Immunologic↗
PubMed1991

Dopaminergic control of feline hippocampal epilepsy: a nigro hippocampal pathway.

Substantia nigra is a mesencephalic structure inserted along several circuits which appear to play a key role in epilepsy. In previous researches we postulated that substantia nigra pars compacta (SNpc) may be the site of a precise control of hippocampal epilepsy while substantia nigra pars reticulata (SNpr) may exert a modulation of both neocortical epilepsy and spreading of hyperactivity toward a motor target. In order to better understand mechanisms subserving nigral action in feline hippocampal epilepsy we electrically stimulated SNpc (dopaminergic), before and after sulpiride (dopamine receptor-antagonist) intravenous injection. Furthermore we compared hippocampal epileptiform activity prior to and after apomorphine (dopamine receptor-agonist) intrahippocampal injection as well as prior to and after SNpc electrolytic destruction. Results showed that SNpc is able to regulate hippocampal epilepsy. This effect is selectively antagonized by sulpiride while apomorphine exerts, synergically with SNpc stimulation, inhibitory effects. On the contrary SNpc lesions induces a significant enhancement of hippocampal epileptiform spikes. Experimental findings suggest that SNpc represents a strategic region for the control of hippocampal excitability and that this regulation appears to be dopaminergic in nature.

Animals↗
PubMed1991

A feature of caudate control of focal hippocampal epilepsy: evidence for an anterograde pathway.

Previous experimental evidences showed that the caudate nucleus has a modulatory effect on hippocampal epilepsy. The caudate's regulating action might reach the hippocampus either via the septal region or, retrogradely, via the accumbens nucleus. In order to obtain new data about the pathway involved in caudate hippocampal influence the spreading of abnormal activity towards the nucleus accumbens was studied. Furthermore the effects of caudate stimulation in animals with electrolytic lesions of the nucleus accumbens were analyzed. It was observed that abnormal penicillin-induced activity spreaded from the hippocampus to the nucleus accumbens in about 30 minutes. In animals with and without lesions of nucleus accumbens, caudate stimulation brought about a significant decrease in the frequency and amplitude of hippocampal activity. The results suggest that the nucleus accumbens is reached by the spreading of hippocampal epilepsy but does not participate in the control exerted by the caudate nucleus on the hippocampus. Thus the caudate-induced inhibition takes place through an anterograde caudate-hippocampal circuit, while at the same time excluding retrograde activation by way of a caudate-accumbens-hippocampal pathway.

Animals↗