Showing papers by "University of Cagliari published in 1995"

Intravenous cocaine, morphine, and amphetamine preferentially increase extracellular dopamine in the "shell" as compared with the "core" of the rat nucleus accumbens

Abstract: The nucleus accumbens is considered a critical target of the action of drugs of abuse. In this nucleus a "shell" and a "core" have been distinguished on the basis of anatomical and histochemical criteria. The present study investigated the effect in freely moving rats of intravenous cocaine, amphetamine, and morphine on extracellular dopamine concentrations in the nucleus accumbens shell and core by means of microdialysis with vertically implanted concentric probes. Doses selected were in the range of those known to sustain drug self-administration in rats. Morphine, at 0.2 and 0.4 mg/kg, and cocaine, at 0.5 mg/kg, increased extracellular dopamine selectivity in the shell. Higher doses of cocaine (1.0 mg/kg) and the lowest dose of amphetamine tested (0.125 mg/kg) increased extracellular dopamine both in the shell and in the core, but the effect was significantly more pronounced in the shell compared with the core. Only the highest dose of amphetamine (0.250 mg/kg) increased extracellular dopamine in the shell and in the core to a similar extent. The present results provide in vivo neurochemical evidence for a functional compartmentation within the nucleus accumbens and for a preferential effect of psychostimulants and morphine in the shell of the nucleus accumbens at doses known to sustain intravenous drug self-administration.

The Aging Thyroid

Abstract: I. Introduction THE number and proportion of elderly people are steadily growing in western societies as a consequence of increased life expectancy and reduced birth rate. This phenomenon has important social, economical, and public health implications and has generated a number of studies aimed at clarifying the basis of the physiological and pathological aspects of aging. In this context, endocrine function in the elderly has been the object of particular attention (1–9). An important concept derived from these studies is that while the equilibrium concentrations of the principal hormones are substantially normal in most healthy elderly, with advancing age there are significant alterations in hormone production, metabolism, and action, with consequent achievement of new equilibria. As proposed by Mooradian et al. (4), aging may be defined as a time of reduced adaptability to metabolic perturbation. It has been repeatedly suggested that some of these changes may play a role in the pathophysiology of sene...

Representing Spatial Information for Limb Movement: Role of Area 5 in the Monkey

Abstract: How is spatial information for limb movement encoded in the brain? Computational and psychophysical studies suggest that beginning hand position, via-points, and target are specified relative to the body to afford a comparison between the sensory (e.g., kinesthetic) reafferences and the commands that generate limb movement. Here we propose that the superior parietal lobule (Brodmann area 5) might represent a substrate for a body-centered positional code. Monkeys made arm movements in different parts of 3D space in a reaction-time task. We found that the activity of area 5 neurons can be related to either the starting point, or the final point, or combinations of the two. Neural activity is monotonically tuned in a body-centered frame of reference, whose coordinates define the azimuth, elevation, and distance of the hand. Each spatial coordinate tends to be encoded in a different subpopulation of neurons. This parcellation could be a neural correlate of the psychophysical observation that these spatial parameters are processed in parallel and largely independent of each other in man.

Antibacterial polyphenols from olive oil mill waste waters.

Abstract: Olive oil vegetation waters (VW) were highly toxic to both phytopathogenic Pseudomonas syringae (Smith, Yung et al.) pv. savastanoi (Gram-negative) and Corynebacterium michiganense (Gram-positive) and showed bactericidal activity in their original concentration (in raw form). Among the main polyphenols, present in the waste waters, methylcatechol proved to be the most toxic to Ps. savastanoi at 10(-4) mol l-1, and also demonstrated bactericidal activity, while on Coryne. michiganense it was only slightly active; catechol and hydroxytyrosol were less active on Ps. savastanoi, but inactive on Coryne. michiganense; tyrosol and its synthetic isomers 1,2- and 1,3-tyrosol were completely inactive on both bacteria. Among the derivatives of VW polyphenols considered, acetylcatechol and guaiacol were selectively toxic for Ps. savastanoi, while o-quinone was strongly toxic for both bacteria. The minor carboxylic polyphenols of VW at 10(-4) mol l-1 were all inactive on the bacteria. VW, catechol, 4-methylcatechol and the less abundant carboxylic polyphenols proved to be toxic on Hep2 human cells. Finally the possibility of using the active polyphenols in agriculture in an integrated pest management program for the protection of the olive plant is discussed.

Cell-death - current difficulties in discriminating apoptosis from necrosis in the context of pathological processes in-vivo

Abstract: The term apoptosis was proposed to define a type of cell death morphologically, biochemically, and molecularly distinct from necrosis, which plays a fundamental regulatory function in the control of the overall size of cell populations, being complementary but opposite to cell proliferation [Kerr et al. (1972): Br J Cancer 26:239-257]. This view has led to the appreciation that apoptosis is an integral part of normal biological processes and may impact on disease states. Introduction of the concept of apoptosis has raised great interest and many studies have been aimed to the identification of genes responsible for the induction of cell death. Indeed, over the past few years, many genes whose expression is associated with cell death have been described, and the molecular mechanisms underlying cell death have been, in some circumstances, clearly established. However, it is now evident that extension of the conclusions achieved by studies performed with highly selected in vitro systems (simple systems), to in vivo conditions (complex systems), has generated a certain degree of confusion. This is in part due to the indiscriminate use of the term apoptosis and to the uncertainty whether apoptosis is always different from necrosis, and, if this is the case, to the lack of well established criteria to discriminate the two processes; in addition, it still remains to be established whether both types of cell death, although different, could be induced simultaneously by the same agent, depending on the cell type and the experimental condition used. The distinction between apoptosis and necrosis, is not simply a problem of terminology; if necrosis and apoptosis are different from a mechanistic point of view, and if necrosis is merely the passive result of cellular injury (still to be shown), it becomes critical to discriminate between the two processes, in order to understand how to modulate apoptosis in view of its potential therapeutic use. This review will summarize existing informations and discuss some of the conflicting issues related to cell death in the liver.

Relevance of residue 116 of HLA‐B27 in determining susceptibility to ankylosing spondylitis

Abstract: Ankylosing spondylitis (AS) is an autoimmune disorder strongly associated with HLA-B27. A direct role of B27 molecules in the disease pathogenesis has been postulated, possibly by presenting to T cells an as-yet unidentified arthritogenic peptide that triggers the autoimmune response. There are nine HLA-B27 alleles differing from each other at one or more amino acid positions. It is important, for the identification of the arthritogenic peptide, to define which alleles, and therefore which polymorphic positions, predispose to the disease. Here, we report that HLA-B*2709 is not associated with AS, as it was not found in patients. HLA-B*2709 differs from the most frequent and disease-associated HLA-B*2705 allele for a single substitution (His vs. Asp) at position 116. Amino acid 116 is located at the bottom of the groove where the antigenic peptide sits, and it has been proven to influence the peptide-binding specificity of HLA class I molecules. The most likely interpretation of these data is that the differences in charge and size that accompany the His-to-Asp substitution exclude the acceptance of the arthritogenic peptide.

The Multiple Functions of Hemoglobin

Abstract: The aim of this review is to focus and discuss several parallel biological functions of hemoglobin besides its basic function of oxygen transport. In light of the information present in the literature the following possible physiological roles of hemoglobin are discussed: (1) hemoglobin as molecular heat transducer through its oxygenation-deoxygenation cycle, (2) hemoglobin as modulator of erythrocyte metabolism, (3) hemoglobin oxidation as an onset of erythrocyte senescence, (4) hemoglobin and its implication in genetic resistance to malaria, (5) enzymatic activities of hemoglobin and interactions with drugs, and (6) hemoglobin as source of physiological active catabolites.

Profound decrease of mesolimbic dopaminergic neuronal activity in morphine withdrawn rats.

Abstract: The spontaneous neuronal activity of meso-accumbens dopaminergic neurons was recorded in unanesthetized rats withdrawn from chronic morphine administration (15 days) by means of single cell extracellular recording techniques coupled with antidromic identification from the nucleus accumbens. Twenty-four h after last morphine administration, firing rate and burst firing were found to be drastically reduced and the relative refractory periods of the same neurons were prolonged in morphine-dependent rats as compared with chronic saline-treated controls. The number of spontaneously active dopaminergic neurons, however, did not differ between the two groups. Administration of morphine restored electrophysiological parameters. When rats were tested 2 h after last morphine administration, i.v. challenge with the opiate antagonist naloxone caused an abrupt and virtually complete reduction of dopaminergic firing rate, burst rate and a prolongation of the relative refractory period. These effects were not observed in control rats. The results indicate that the mesolimbic dopaminergic system is tonically reduced in its activity during morphine withdrawal syndrome and considering its role in the reinforcing properties of opioids, its depressed activity during the morphine withdrawal syndrome may bear relevance for the dysphoric state associated to morphine withdrawal in humans.

Pediatric-onset bipolar disorder: a neglected clinical and public health problem.

Abstract: Bipolar disorder (BPD), probably the most prevalent psychotic disorder in adults, has been relatively neglected or controversial in children and adolescents over the past century. We reviewed the literature on early-onset BPD.* Estimates of prevalence, particularly before puberty, are limited by historical biases against pediatric mood disorders and by formidable diagnostic complexity and comorbidity. Although clinical features of pediatric and adult BPD have similarities, pediatric cases probably cannot be defined solely by features characteristic of adult cases. Onset was before age 20 years in at least 25% of reported BPD cases, with some increase in this incidence over the past century. Pediatric BPD is familial more often than is adult-onset BPD, may be associated with a premorbid cyclothymic or hyperthymic temperament, and can be precipitated by antidepressant treatment. Pediatric BPD episodes frequently include irritability, dysphoria, or psychotic symptoms; they are commonly chronic and carry high...

Molecular pathology and haplotype analysis of Wilson disease in Mediterranean populations

Abstract: We analyzed mutations and defined the chromosomal haplotype in 127 patients and Mediterranean descent who were affected by Wilson disease (WD), 39 Sardinians, 49 Italians, 33 Turks, and 6 Albanians Haplotypes were derived by use of the microsatellite markers D13S301, D13S296, D13S297, and D13S298, which are linked to the WD locus There were five common haplotypes in Sardinians, three in Italians, and two in Turks, which accounted for 85%, 32%, and 30% of the WD chromosomes, respectively We identified 16 novel mutations: 8 frameshifts, 7 missense mutations, and 1 splicing defect In addition, we detected the previously described mutations: 2302insC, 3404delC, Arg1320ter, Gly944-Ser, and His1070Gin Of the new mutations detected two, the 1515insT on haplotype I and 2464delC on haplotype XVI, accounted for 6% and 13%, respectively, of the mutations in WD chromosomes in the Sardinian population Mutations H1070Q, 2302insC, and 2533delA represented 13%, 8%, and 8%, respectively, of the mutations in WD chromosomes in other Mediterranean populations The remaining mutations were rare and limited to one or two patients from different populations Thus, WD results from some frequent mutations and many rare defects

Prevention of de-novo adhesion formation after laparoscopic myomectomy : a randomized trial to evaluate the effectiveness of an oxidized regenerated cellulose absorbable barrier

Abstract: To evaluate the effectiveness of the oxidized regenerated cellulose absorbable barrier (Interceed®, TC7) in the prevention of de-novo adhesion formation after laparoscopic myomectomy, a prospective and randomized study was performed at the Department of Obstetrics and Gynaecology of the University of Cagliari, Cagliari, Italy. A total of 50 pre-menopausal non-pregnant women, aged 23-42 years, who submitted to laparoscopic myomectomy from January 1993 to June 1994, were randomized to surgery alone (control group, n = 25) or surgery and oxidized regenerated cellulose barrier (Interceed group, n = 25). Neither group received any other treatment for adhesion prevention. A second-look laparoscopy was performed 12-14 weeks after laparoscopic myomectomy. The incidence of adhesion-free patients was assessed at second-look laparoscopy by an investigator not informed of the treatment. The numbers of adhesion-free patients were three out of 25 (12%) in the control group and 15 out of 25 (60%) in the treatment group (P < 0.05). In conclusion, the oxidized regenerated cellulose absorbable barrier significantly reduced de-novo adhesion formation after laparoscopic myomectomy.