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Biomedical subjects

E Palma

Publications and source records attributed to E Palma.

At least 55 records · Page 3Linked to original sources
PubMed1996

The influence of obesity in the sexual life of women in menopause. A case control study.

It seemed important to us to investigate sexuality during the post-menopausal and senile period to evaluate whether changes in sexual behaviour are related with endocrine-functional alterations brought on by menopause, or whether social-economic and environmental factors represent the principal cause. Thus 1,500 questionnaires were distributed to women aged from 50 to 87. Of the 1,500 questionnaires distributed, only 713 (47.53%) were returned completely filled-in. All women had been classified for age, civil status and life environment. Our statistic analysis does not seem to have singled out those factors that influence sexual activity in women of advanced age but shows only how age, indifferently from civil status and life environment, represents the most important factor. At the same age other factors, probably attached to psychological features and way of life and thus difficult to define and even less qualifiable, may be of influence, explaining a further percentage of control of those answers not explainable by age.

Age Factors↗
PubMed1995

Protein kinase C modulates exogenous acetylcholine current in Xenopus oocytes.

The modulation of acetylcholine-activated current (IACh) by protein kinase C (PKC) was studied in Xenopus laevis oocytes microinjected with either mRNA extracted from C2C12 myotubes (C2C12 mRNA) or RNAs encoding murine alpha beta gamma delta subunits of the nicotinic ACh receptor (nAChR). Voltage-clamped oocytes were treated for 90 sec with 12-O-tetradecanoylphorbol-13-acetate (TPA, 300 nM), a potent PKC activator. Transient increase in the amplitude and acceleration in the decay of IACh were invariably observed within minutes of TPA application, and were independent of extracellular Ca2+ concentration. Both parameters recovered to control within 20-30 min; then a slight depression of IACh developed. By this time, an initial PKC down regulation was observed. At the peak of TPA-induced potentiation, dose-response relations suggested an increased binding affinity of nAChR for the neurotransmitter. 4 alpha-phorbol 12,13-didecanoate (300 nM), a biologically inactive analogue of TPA, did not affect IACh, while staurosporine (5-10 microM), a potent inhibitor of PKC activity, suppressed the action of TPA on IACh. In oocytes co-injected with C2C12 mRNA and with rat brain mRNA, IACh was potentiated by 5-hydroxy-tryptamine (10 microM), whose receptors are coupled to phosphoinositide hydrolysis. The nAChR-channel activity in cell-attached patches increased when TPA was applied to the oocytes. In 50% of the oocytes examined, a sustained depression of the single channel activity followed. We conclude that in Xenopus oocytes an endogenous PKC system regulates the function of embryonic-type muscle nAChRs.

Acetylcholine↗
PubMed1995

Two forms of acetylcholine receptor gamma subunit in mouse muscle.

Nicotinic acetylcholine receptors (nAcChoRs) of skeletal muscle are heterosubunit ligand-gated channels that mediate signal transmission from motor nerves to muscle. While cloning murine nAcChoR subunits, to gain an insight into the receptor diversity across species, we detected two forms of gamma subunits in the myogenic C2C12 cell line. Both forms are functional when expressed in Xenopus oocytes. One gamma subunit [long gamma (gamma 1)] was almost identical to that previously cloned in the murine BC3H-1 tumor cell line. The second form of gamma subunit [short gamma (gamma s)] lacked 156 bp (52 amino acids) in the extracellular N terminus, adjoining the hydrophobic segment M1, which corresponds to the fifth exon of the gamma-subunit gene. The two forms of gamma subunit coexist during myogenesis in vitro and in 17-day embryonic and denervated adult muscle fibers in vivo. However, the gamma s variant was the only form of gamma subunit in newborn muscle. In dissociated muscle fibers of newborn mice, AcCho-evoked channel openings were more prolonged when compared with C2C12 myotubes or denervated adult muscle fibers. The gamma s subunit may, thus, contribute to the structural and functional diversity of nAcChoRs in muscle cells.

Acetylcholine↗
PubMed1995

Lack of involvement of nitric oxide in the mechanisms of seizures and hippocampal damage produced by kainate and ouabain in rats.

The gross behavioural, electrocortical and neuropathological effects of kainate (10 mg/kg i.p,) and ouabain (1 micrograms, given into one dorsal hippocampus) were studied in rats. The effects of these treatments on nitric oxide synthase (NOS) activity in homogenates of hippocampus and cortex were also studied. Administration of kainate or ouabain produced motor and electrocortical seizures similar for latency to onset (approximately 15 min) and intensity (in all instances 80-100% of the treated rats showed behavioural and electrographic seizures). These effects were accompanied at 24 h by severe damage to all subsectors of the hippocampal formation and this concerned a similar proportion of the treated rats (n = 4-8 per treatment). No significant changes in nitric oxide synthase (NOS) activity were noted in the cerebral cortex and hippocampus of rats receiving injections of kainate and ouabain. In addition, pretreatment with N omega-Nitro-L-arginine methyl ester (300 micrograms, given into one lateral cerebral ventricle 15 min previously) was ineffective in preventing the effects of kainate and ouabain. In conclusion, present data suggest that excessive production of NO is not involved in the mechanisms triggering seizures and neurodegeneration produced by kainate or ouabain.

Amino Acid Oxidoreductases↗
PubMed1995

The desensitization of the embryonic mouse muscle acetylcholine receptor depends on the cellular environment.

The rate of desensitization of nicotinic acetylcholine (ACh) receptor (nAChR), an important characteristic of nAChR function, was studied in myotubes of the mouse C2C12 cell line at different times after fusion, by measuring the decay of ACh-evoked currents (IACh) under various patch-clamp configurations. We observed a progressive slowing of IACh decay rate (half-decay time rose from about 0.5 s to over 5 s) in myotubes of increasing size (i.e. age) under all experimental conditions, except in outside-out patches, when IACh decayed as fast as in the smallest myotubes. Single-channel conductance (about 35 pS) and open time (about 3.5 ms), measured in outside-out and cell-attached patches, were independent of myotube size. In Xenopus oocytes injected with poly(A+)RNA extracted from C2C12 myoblasts or mature myotubes, IACh decay was about 50 times slower than in myotubes. Neither cAMP-dependent nor diacylglycerol-dependent protein kinases, actin nor microtubule polymerization state influenced IACh decay. Our data indicate that the cellular environment, but not readily dialysable cytosolic factors, markedly influences the functional behaviour of nAChR.

Acetylcholine↗
PubMed1995

Regional distribution of epidermal growth factor, testosterone and dihydrotestosterone in benign prostatic hyperplasia tissue.

In benign prostatic hyperplasia (BPH), basic fibroblast growth factor (bFGF) is found to have a regional distribution, with concentrations in the periurethral zone (where the primitive fibrostromal nodule originates) higher than those of the peripheral subcapsular zone. The aim of the present investigation was to verify whether androgens and epidermal growth factor (EGF) are uniformly distributed from the periurethral to the peripheral zone or whether they show regional differences. Tissue samples, removed by transvesical resection from nine untreated BPH patients, sectioned in periurethral, subcapsular, and intermediate zones, were examined. In the periurethral zone, dihydrotestosterone (DHT), testosterone, and EGF, determined by radioimmunoassay (RIA) techniques after purification on Celite microcolumns and Sep-pak C18 cartridge, showed values significantly higher (mean +/- SD: 1121 +/- 482 pg, 250 +/- 129 pg, and 6.89 +/- 3.28 ng/mg DNA, respectively; P < 0.01) than those of the subcapsular zone (489 +/- 190 pg, 114 +/- 70 pg, and 3.40 +/- 1.90 ng/mg DNA, respectively). A positive linear correlation between EGF, testosterone, and DHT was also observed. The regional distribution of EGF, testosterone, and DHT was similar to that found for bFGF: the highest levels of these factors in the periurethral region allow us to hypothesize on their possible involvement in the rewakening of mesenchymal tissue, leading to the formation of the primitive fibrostromal nodule and then to BPH development.

Data Interpretation, Statistical↗
PubMed1994

Effects of perphenazine on the metabolism of inositol phospholipids in SK-N-BE(2) human neuroblastoma cells.

Administration of myo-[3H]inositol to SK-N-BE(2) human neuroblastoma cells for 24 hr resulted in equilibrium labelling of phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2), as well as in retention of a large intracellular pool of free myo-[3H]inositol. Equilibrium labelling was no longer observed when cells were treated for 2 hr with 20 microM perphenazine (PPZ) in label-free medium; under these conditions, myo-[3H]inositol from the retained intracellular pool was incorporated into PI and PIP but not into PIP2. Analysis of water-soluble myo-[3H]inositol derivatives and inositol 1,4,5-trisphosphate mass determination indicated that PPZ did not stimulate phosphoinositide hydrolysis by phospholipase C. These results indicate that PPZ raises PI and PIP levels, whereas it is ineffective in expanding the PIP2 pool. The latter effect is not due to a concomitant synthesis and hydrolysis of this lipid.

Cell Line↗
PubMed1994

Intracerebral injection of human immunodeficiency virus type 1 coat glycoprotein GP120 does not produce neurodegeneration in rats.

The human immunodeficiency virus type 1 (HIV-1) coat glycoprotein, GP120 has been reported to cause death of several neuronal cell types maintained in vitro. In the present experiments the gross behavioural, electrocortical (ECoG) and neuropathological effects of GP120 were studied in rats chronically microinfused into one lateral cerebral ventricle (i.c.v.) via mini-osmotic pumps. Treatment with GP120 (100 ng/day) for 1, 7 and 14 consecutive days lacked postural, motor and ECoG effects nor did it produce any apparent brain damage. In addition, acute i.c.v. injection of a subconvulsive dose (500 ng) of N-methyl-D-aspartate (NMDA) did not produce motor and ECoG epileptogenic discharges in rats which received 1 h beforehand a dose of GP120 (900 ng) into the dorsal hippocampus ipsilateral to the injected ventricle; per se this dose of GP120 was ineffective. In conclusion, the present experiments demonstrate that acute or chronic microinfusion of GP120 into the rat cerebral ventricular system does not produce neurotoxic effects. In addition, they demonstrate that intrahippocampal GP120 does not sensitize rats to the excitotoxic effects of a subconvulsive dose of NMDA.

Animals↗
PubMed1994

Age-dependent appearance of synaptic currents in rat neocortical neurons in culture.

Rat neocortical neurons grown in dissociated cell culture were recorded with the whole-cell patch-clamp technique. Spontaneous inward currents were observed in cells that were held at a membrane potential of -80 mV in medium containing tetrodotoxin and Cd2+. These currents displayed amplitudes up to 140 pA and rise time of 1.8 +/- 0.2 ms (mean +/- SD, n = 15). They reversed near 0 mV and showed no voltage-dependent frequency of occurrence. Hence, they were presumably due to spontaneous release of transmitter. The inward currents appeared around day 10 in culture and were detected up to 4 weeks. When cells of different ages were compared, the maximal probability of recording these inward events occurred at around 3 weeks in culture. The inward currents were not reduced by application of bicuculline methiodide which is a competitive antagonist of the GABAA receptor, but were blocked by the broad-spectrum glutamate receptor antagonist kynurenic acid. Moreover, spontaneous inward events were not affected by DL-2-aminophosphono-valerate (NMDA receptor antagonist) but disappeared following application of the non-NMDA receptors antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Our observations indicate that the inward currents represent miniature synaptic events that are primarily mediated by non-NMDA excitatory amino acid receptor subtypes. Furthermore, our findings indicate that they develop over time and are not present in neurons that are grown in culture for less than 10 days.

2-Amino-5-phosphonovalerate↗
PubMed1993

Arachidonic acid augments potassium currents in rat neocortical neurones.

We analysed the effects induced by arachidonic acid on voltage-dependent outward currents generated by rat neocortical neurones in culture in the presence of Na+ and Ca2+ channel blockers. These currents, recorded with whole-cell voltage-clamping techniques, were presumably carried by K+ and were characterized by an early transient and a late persistent component. Extracellular application of arachidonic acid (50 microM) enhanced both components of the voltage-dependent K+ response by 15-29% (n > 20 cells). These effects were reversible and not observed when a low dose (50 microM) of indomethacin was present in the bath (n = 7 cells). We conclude that one or more of the arachidonic acid metabolites of the cyclooxygenase pathway might be involved in the modulation of outward currents in neocortical cells in culture.

Animals↗
PubMed1993

[Clinico-radiological correlation in thalassemia intermedia].

Fifteen thalassemia intermedia patients were considered, whose clinical and radiological findings were examined and compared. Eight patients underwent regular transfusion therapy. All patients underwent total body CT: the volume of ectopic erythropoiesis foci was calculated by a digital calculation algorithm (ROI volume). This work was aimed at correlating the quantitative measures of ectopic erythropoiesis assessed by CT with serum level of erythropoietin (EPO) and of trasferrin-free receptors (TfR) in both transfused and non-transfused patients, also considering the volume changes of ectopic erythropoiesis and bone changes over 36 months' follow-up. A direct correlation was demonstrated between serum transferrin and ectopic erythropoietic masses in transfusion-dependent patients: in fact, increased values of serum transferrin correspond to the enlargement of these masses and to bone lesion worsening.

Adolescent↗
PubMed1992

Immunoreactive EGF in human benign prostatic hyperplasia: relationships with androgen and estrogen receptors.

Benign prostatic hyperplasia (BPH) is a sex steroid dependent disease. Estrogens and androgens can modulate in different mammalian tissues epidermal growth factor (EGF) production and/or secretion. In order to clarify the relationships between estrogen and androgen receptor concentrations and those of immunoreactive EGF (irEGF), we have evaluated these parameters in 14 human BPH samples, by means of a dextran-coated charcoal method and radioimmunoassay, respectively. Cytosolic steroid receptors did not seem to correlate with irEGF. A linear significative relationship was evident between nuclear androgen receptor (ARn) levels and endogenous irEGF but not between nuclear estrogen receptors and irEGF: in ARn negative BPH samples, irEGF levels were lower than in ARn positive ones. Therefore, it is possible that androgens act at prostatic tissue level, through their own receptors, by modulating EGF production and/or secretion.

Aged↗
PubMed1992

Sex steroid hormones in the pathogenesis of chronic subdural haematoma.

In order to verify whether hormonal factors could be involved in the pathogenesis of Chronic Subdural Haematoma (CSDH), based on clinical and epidemiological demonstration of higher incidence of this disease in male patients and particularly in those with high urinary estrogen values, Estradiol (ER) and Progesterone (PR) Receptors were studied in the Haematoma External Membrane (HEM) in 18 male and 7 female CSDH patients. The observed higher incidence of ER and PR in male rather than in female patients (73% vs 27% and 72% vs 28% for male and female patients respectively), and the higher concentration of ER in the HEM of male rather then female patients (55 +/- 15 S.E. vs 13 +/- 7 S.E. fmol/mg protein) suggest that this pathological process, which affects individuals whose gonadal activity is quiescent, is mainly dependent upon hormonal local effect played by estrogen compounds on the HEM of the male patients. In this sex, in fact, whose tissues are not usually adapted to an estrogen action, the effect of estrogens on a responsive tissue such as the newly-vascularized HEM could lead to an increased formation of tissue Plasminogen Activator (t-PA), a compound that, escaping into the subdural collection, could maintain a local hyperfibrinolysis with formation of Fibrinogen Degradation Products (FDP). Therefore local hyperfibrinolysis enhanced by steroid hormones and the subsequent CSDH may perhaps be influenced by the prophylactic or adjuvant treatment with inhibitors either of the aromatase activity or of the estrogen action at receptor level.

Aged↗
PubMed1992

Evidence that Serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients.

A double-blind placebo-controlled study was performed in 35 benign prostatic hypertrophy (BPH) patients never treated before. The patients were randomized into two groups, the 1st (18 cases) receiving Serenoa repens extract (160 mg t.d.) for 3 months up to the day before the operation of transvesical adenomectomy and the 2nd (17 cases) receiving placebo. Steroid receptors were evaluated in the nuclear (n) and cytosolic (c) fraction using the saturation analysis technique (Scatchard analysis or single saturating-dose assay) for androgen (AR) and estrogen (ER) receptors and the enzyme immunoassay (EIA) for ER and progesterone receptors (PgR). Scatchard analysis of ERc and ERn revealed the presence of two classes of binding sites, one with high-affinity low-capacity binding and the other with low-affinity high-capacity binding. In the untreated BPH group, ER were higher in the n than in the c fraction: ERn were positive in 14 cases and ERc in 12 of 17 cases. In the BPH group treated with S. repens extract on the contrary, ERn were negative for both binding classes in 17 cases and ERc in 6 of 18 cases. Using EIA, ERn and ERc were detected in all 15 samples examined, but in the treated group, ERn were significantly (p less than 0.01) lower than in the untreated group, whilst ERc remained almost unchanged. Similar results were obtained measuring PgR: the n fraction of the treated group prostatic samples was significantly (p less than 0.01) lower than that of the untreated group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Modulation of voltage-activated channels by calcitonin gene-related peptide in cultured rat neurones.

1. Whole-cell currents were recorded from cultures of dissociated neocortical neurones of the rat. Rat alpha-calcitonin gene-related peptide (CGRP; 1 nM-1 microM) caused significant dose-dependent decreases in the voltage-activated transient (A-current) and delayed rectifier K+ currents. Forskolin (10 nM-20 microM) mimicked this effect. Peak K+ currents were gradually decreased after loading neurones with cyclic AMP (100 microM) through patch pipettes. CGRP was ineffective in neurones loaded with cyclic AMP. 2. CGRP (0.5-2 microM) increased cytosolic cyclic AMP concentration and this effect was mimicked by forskolin (5-40 microM). 3. CGRP (0.1-1 microM) reduced high-threshold Ca2+ currents; as did forskolin (5-20 microM) and cyclic AMP loaded into the neurones. In contrast, low-threshold Ca2+ currents were not affected by any of these agents. 4. Voltage-activated Na+ currents were significantly reduced by both CGRP (0.1-1 microM) and forskolin (5-20 microM). A similar effect was observed when cells were loaded with cyclic AMP. 5. We conclude that, in neocortical neurones, CGRP attenuates voltage-activated currents by stimulating the intracellular cyclic AMP signalling system.

Animals↗
PubMed1990

Potassium currents in rat cortical neurons in culture are enhanced by the antiepileptic drug carbamazepine.

We report that carbamazepine (Tegretol), a drug that is useful for the treatment of complex partial seizures, enhances outward, voltage-dependent K+ currents generated by rat neocortical cells in culture and recorded with patch-clamping techniques. This effect is seen in the presence of therapeutic concentrations of carbamazepine (10-20 microM). Furthermore, at these doses carbamazepine does not influence voltage-dependent inward Na+ and Ca2+ currents recorded in these cells. The action exerted by carbamazepine on K+ currents is a novel finding and might represent an important mechanism for controlling neocortical excitability and thus the generation of epileptiform activity.

4-Aminopyridine↗