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Biomedical subjects

A Romani

Publications and source records attributed to A Romani.

At least 19 recordsLinked to original sources
PubMed1995

Pavia memory project: study design and first results.

This paper describes the design and first results of the cross-sectional phase of a study on memory impairment in elderly subjects (Pavia Memory Project). The target population consisted of the 1,046 subjects born in 1925 and currently living in Pavia. Four hundred and thirty-six subjects (plus 287 interviewed at home) participated in the first stage, which consisted of a semi-structured anamnestic interview. The 400 interviewed subjects with none of the exclusion criteria participated in the second stage, which consisted of a memory test battery, a standardized neurological examination and screening procedures for depression (GDS) and dementia (MMSE). On the basis of the memory scores, three groups were defined: memory impairment (MI: 8.8%), mild memory impairment (MMI: 39.8%); normal (N: 51.3%). There were more failures on the visuo-spatial memory tests. Depression was equally distributed in the N and MI groups (about 15%), but was more frequent in the MMI group (27%). Abnormal neurological signs were largely independent of memory performance. Two cohorts (of MI and N subjects) underwent neuropsychological and instrumental (CT-scan, EEG, ERPs, eye movements) assessment, which will be regularly repeated in the longitudinal phase.

Aged↗
PubMed1995

Recovery functions of early cortical median nerve SSEP components: normative data.

The recovery functions of parietal P14-N20, N20-P27 and frontal P22-N30 amplitudes were assessed in 17 healthy controls aged 20-50 years by means of the paired stimulus technique. One unpaired and 4 paired stimuli with interstimulus intervals (ISIs) of 25, 50, 75 and 100 msec were cyclically presented in a single run. Responses to the unpaired stimulus were subtracted off-line from paired stimulus responses. The highest suppression was reached at shorter ISIs for components with shorter latencies. The mean suppression of P22-N30 was influenced by the subject's age, being greater in younger subjects. Normative data are reported.

Adult↗
PubMed1995

Differential regulation of circulating Mg2+ in the rat by beta 1- and beta 2-adrenergic receptor stimulation.

Extracellular Mg2+ homeostasis was studied in vivo in the anesthetized rat. Animals were infused with isoproterenol (ISO) for 10 minutes, and serum Mg2+ was measured after the infusion and then 10 and 20 minutes later. A dose-dependent increase in circulating Mg2+ was observed in animals infused with ISO at a rate of 0.1 microgram.kg-1.min-1 or higher. The time course of the effect demonstrated that circulating Mg2+ continued to increase 20 minutes after the end of the ISO infusion. A predicted maximal increase in serum Mg2+ concentration of 19.3% was derived with a predicted EC50 of 0.08 microgram.kg-1.min-1. The maximal percent increase corresponded to a net increase of 6.7 mumol/300 g body wt. Because infusion of ISO resulted in changes in hemodynamic parameters, most notably a drop in blood pressure, a group of animals was infused with nitroprusside to mimic the hypotensive response via a nonadrenergic mechanism. Under these conditions, there was a transient increase in circulating Mg2+ that was largely inhibited by propranolol, indicating that hypotension per se was not responsible for the mobilization of Mg2+. Infusion of salbutamol, but not prenalterol, also induced an increase in circulating Mg2+. Pretreatment with butoxamine, ICI-118551, or propranolol prevented the ISO-induced increase in serum Mg2+. Pretreatment with atenolol minimally affected the ISO-induced changes in circulating Mg2+. Pretreatment with CGP-20271A actually enhanced the ISO-induced increase in circulating Mg2+. This evidence demonstrates the existence of a pool of Mg2+ that is mobilized into the circulation in response to selective beta 2-adrenergic stimulation.

Adrenergic beta-Antagonists↗
PubMed1994

Usefulness of trigeminal somatosensory evoked potentials to detect subclinical trigeminal impairment in multiple sclerosis patients.

Trigeminal somatosensory evoked potentials (TSEPs) by surface electric pulse stimulation were recorded in 30 normal subjects and in 70 multiple sclerosis (MS) patients, 13 of whom presenting clinical trigeminal impairment. We observed significant prolongation of all TSEPs parameters in MS group. TSEPs were abnormal in 45 patients (64.3%). Clinical and neurophysiological data agreed in 36 patients (51%) on 84 sides (60%). TSEPs were able to detect clinically silent lesions 54 times. TSEPs recording proves to be an additional useful test in MS multimodal evoked potential protocols.

Adolescent↗
PubMed1994

[Treatment of dyslipidemia of the elderly with simvastatin and pravastatin. Effectiveness and tolerance].

After reviewing the literature concerning the advisability and efficacy of dyslipidemia treatment in old age, the authors present their experience with the use of HMG CoA reductase inhibitors. Twenty-five patients were treated with simvastatin and 20 with pravastatin. Already after one month of therapy, both drugs had induced a reduction of total cholesterol, LDL-cholesterol, and triglycerides, as well as an increase of HDL-cholesterol. These changes were found to be even more marked after three months of treatment. Altogether, tolerability of both drugs was good. However, recurrent episodes of nose bleeding were observed in two patients with normal blood clotting activity.

Aged↗
PubMed1992

Capsaicin releases calcitonin gene-related peptide from the human iris and ciliary body in vitro.

Slices of human iris or ciliary body, obtained post-mortem (8-12 h after death, n = 5), were superfused in vitro with capsaicin (10 microM) and the immunoreactivity for substance P (SP-LI) or calcitonin gene-related peptide (CGRP-LI) was measured in the effluent. In the iris and in the ciliary body CGRP-LI was 3.71 +/- 0.74 pmol/g and 3.01 +/- 0.55 pmol/g and SP-LI was 6.68 +/- 0.75 pmol/g and 6.55 +/- 0.84 pmol/g, respectively. A first exposure to capsaicin increased the CGRP-LI outflow from the ciliary body (427 +/- 46 fmol/g/30 min), whereas a second challenge with the drug 30 min later, failed to significantly enhance the CGRP-LI outflow (21.8 +/- 15.6 fmol/g/30 min). Likewise, the capsaicin-evoked increase in CGRP-LI outflow from the iris slices (472 +/- 62 fmol/g/30 min) was no longer observed at the second drug administration (38.4 +/- 12.8 fmol/g/30 min). Capsaicin failed to increase the SP-LI outflow from either the iris or the ciliary body. Reverse phase HPLC analysis of CGRP-LI indicated that authentic CGRP was contained in the tissue and in the superfusate collected during exposure to capsaicin. The present results show that in the human iris and ciliary body, capsaicin releases CGRP possibly contained in terminals of sensory nerves.

Calcitonin Gene-Related Peptide↗
PubMed1992

Regulation of Mg2+ uptake in isolated rat myocytes and hepatocytes by protein kinase C.

A large Mg2+ cell uptake against concentration gradients is stimulated in collagenase-dispersed rat myocytes by carbachol and in hepatocytes by carbachol or vasopressin. The signalling pathway(s) responsible for this stimulation of Mg2+ uptake was investigated by using various activators or inhibitors of protein kinase C (PKC) and by correlating Mg2+ uptake with cell PKC activity and cAMP content. In both cell preparations, the direct stimulation of PKC by diacylglycerol analogs or phorbol esters reproduce the same pattern of Mg2+ uptake as that induced by carbachol or vasopressin. These data indicate that the activation of PKC is responsible for a stimulation of Mg2+ uptake by myocytes or hepatocytes, whereas increase in cAMP in these cells stimulates Mg2+ release.

Animals↗
PubMed1992

cAMP control of Mg2+ homeostasis in heart and liver cells.

The increase of intracellular cAMP level in intact myocytes and hepatocytes induced by beta-adrenergic stimulation or by forskolin or permeant cyclic AMP analogues induces a sizeable Mg2+ efflux from the cells. Approximately 10-15% of total cell Mg2+ is mobilized over 5-8 min stimulation. The addition of cAMP to digitonin-permeabilized hepatocytes also mobilizes Mg2+ from intracellular compartment(s). Furthermore, cAMP stimulates a major Mg2+ extrusion from isolated rat liver mitochondria, indicating this compartment as the main source of Mg2+ mobilization in liver cells.

Animals↗
PubMed1992

Spinal and cortical potentials evoked by tibial nerve stimulation in humans: effects of sex, age and height.

Somatosensory evoked potentials by posterior tibial nerve stimulation at the ankle were performed in 74 healthy volunteers (36 females and 38 males) aged 14-76 years. Cortical potentials were obtained in all subjects and spinal potentials (N22) in 71 subjects. All parameters were related to subject's age, height and sex. Sex influenced only P40-N50 amplitude, which was greater in females. All latencies of spinal and cortical components increased in a similar manner with subject's height (about 0.16-0.18 ms per cm), whereas the N22-P40 interpeak latency was independent from height, but related to T12-Cz distance. Absolute latencies of the spinal and of most cortical components, but not interpeak latencies, increased with subject's age (about 0.06-0.09 ms per year). The parameters to compute normative data (according to univariate or bivariate regression models) are furnished. Limits of right-left differences are reported.

Adolescent↗
PubMed1992

A one-week test-retest reliability study of Brainstem Auditory Evoked Potentials.

Brainstem Auditory Evoked Potentials (BAEPs) are increasingly used in longitudinal evaluation of brainstem function. The reliability of the neurophysiological parameters and definition of the normal test-retest variability are required for such investigations. In the present study we submitted 20 healthy volunteers (10 males and 10 females; mean age 35.1 years, range 24-49) to BAEPs in two sessions separated by seven days. The reliability of the parameters was estimated by means of intraclass correlation coefficient (R). All BAEP parameters showed excellent R values (above 0.75). In addition, the confidence interval lower limits of all R coefficients had good to excellent values. Finally we computed the upper normal limits of the test-retest variability of each parameter, with alpha = 0.01, using the within-subjects mean square. The confirmed good reliability of the analyzed parameters enables us to employ BAEPs as useful monitoring instruments in longitudinal studies.

Adult↗
PubMed1992

The reliability of eye movement quantitative evaluation. I. Saccadic eye movements.

We adopted the estimate of the intraclass coefficient of reliability, R, to evaluate the reliability of saccadic eye movements quantitative analysis. At a one-week interval we recorded refixative saccadic eye movements twice from fifteen healthy subjects by means of the binocular electrooculographic technique. R was computed for the constants and the slopes of the amplitude/duration and the amplitude/peak velocity relationships, for the mean precision values and for the mean latency values adjusted for subject's age. Our data demonstrated that the reliability of saccade parameters is fairly good for the amplitude/peak velocity relationship, good for the precision and very good for the amplitude/duration relationship. Finally, we believe that the normal variability values we obtained can be usefully employed in neurophysiological longitudinal studies not only in normal subjects, but also in pathological condition provided the more reliable parameters and the more adequate strategies to compute normal variability values are chosen.

Adult↗
PubMed1992

The reliability of eye movement quantitative evaluation. II. Smooth pursuit eye movements.

We adopted the estimate of the intraclass coefficient of reliability, R, to evaluate the reliability of smooth pursuit eye movement quantitative analysis. At a one-week interval, we recorded twice smooth pursuit eye movements from fifteen healthy subjects by means of the binocular electrooculographic technique. R was computed for the constant and the slope of the target velocity/gain relationships. R values were rated good for the slope and excellent for the constant. Finally, we computed for each parameter the maximum variability value according to two differing methods; on the basis of the within-subjects mean square values, we defined the normal range of biological test-retest variability for the two parameters.

Adult↗
PubMed1991

Cyclic AMP-induced Mg2+ release from rat liver hepatocytes, permeabilized hepatocytes, and isolated mitochondria.

The addition of norepinephrine, epinephrine, or forskolin to collagenase-dispersed rat liver hepatocytes increase cAMP and result in a 15% loss in total cell Mg2+ within 5 min. Conversely, carbachol and vasopressin induce a 10-15% increase of total cell Mg2+. Permeabilized hepatocytes also mobilize a large pool of Mg2+ when stimulated by ADP or cAMP. This stimulation is completely inhibited by atractyloside and bongkrekic acid, two different specific inhibitors of the mitochondrial adenine nucleotide translocase. cAMP directly mobilizes Mg2+ efflux from isolated rat liver mitochondria. 50 nM cAMP or 250 microM ADP induces in 5 min a mitochondrial loss of about 6 nmol of Mg2+/mg of protein and a stimulation of ATP efflux. The effect of cAMP is specific, is not reproduced by other cyclic or noncyclic nucleotides, and is inhibited by inhibitors of the adenine nucleotide translocase. These data indicate that cAMP is a messenger for a major mobilization of Mg2+ in hepatocytes. A major target for the effect of cAMP are mitochondria, which lose up to 20-25% of their total Mg2+ in 5 min, both within the cell and after isolation. Evidence is presented suggesting that the adenine nucleotide translocase is the target of the cAMP-dependent Mg2+ efflux and that cAMP may change the operation of the translocase. This, in turn, could change within the matrix the substrate of choice of the translocase from ATP to ATP.Mg.

Adenosine Triphosphate↗
PubMed1991

Loss of membrane protein thiols and lipid peroxidation in allyl alcohol hepatotoxicity.

The data reported suggest that--following initiation of lipid peroxidation--membrane protein thiols can be attacked by lipid-derived radicals and/or reactive, lipid-soluble aldehydes like 4-hydroxynonenal and other hydroxyalkenals originated within the lipid core of cell membranes, resulting in a membrane protein thiol loss which is in turn associated with the development of hepatocellular injury.

1-Propanol↗
PubMed1991

Role of a nonmitochondrial Ca2+ pool in the synergistic stimulation by cyclic AMP and vasopressin of Ca2+ uptake in isolated rat hepatocytes.

The subcellular distribution of 45Ca2+ accumulated by isolated rat hepatocytes exposed to dibutyryl cyclic AMP (dbcAMP) followed by vasopressin (Vp) was studied by means of a nondisruptive technique. When treated with dbcAMP followed by vasopressin, hepatocytes obtained from fed rats accumulated an amount of Ca2+ approximately fivefold higher than that attained under control conditions. Ca2+ released from the mitochondrial compartment by the uncoupler carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) accounted for only a minor portion of the accumulated Ca2+. The largest portion was released by the Ca2+ ionophore A23187 and was attributable to a nonmitochondrial compartment. DbcAMP + Vp-treatment also caused a maximal stimulation of glucose production and a twofold increase in cellular glucose 6-phosphate levels. In hepatocytes obtained from fasted rats, dbcAMP + Vp-stimulated Ca2+ accumulation was lower, although with the same subcellular distribution, and was associated with a minimal glucose production. In the presence of gluconeogenetic substrates (lactate plus pyruvate) hepatocytes from fasted rats were comparable to cells isolated from fed animals. However, Ca2+ accumulation and glucose 6-phosphate production could be dissociated in the absence of dbcAMP, in the presence of lactate/pyruvate alone. Under this condition in fact Vp induced only a minimal accumulation of Ca2+ in hepatocytes isolated from fasted rats, although glucose production was markedly increased. Moreover, treatment of fed rat hepatocytes with 1 mM ATP caused a maximal activation of glycogenolysis, but only a moderate stimulation of cellular Ca2+ accumulation. In this case, sequestration of Ca2+ occurred mainly in the mitochondrial compartment. By contrast, the addition of ATP to dbcAMP-pretreated hepatocytes induced a large accumulation of Ca2+ in a nonmitochondrial pool. Additional experiments using the fluorescent Ca2+ indicator Fura-2 showed that dbcAMP pretreatment can enlarge and prolong the elevation of cytosolic free Ca2+ caused by Vp. A nonmitochondrial Ca2+ pool thus appears mainly responsible for the Ca2+ accumulation stimulated by dbcAMP and Vp in isolated hepatocytes, and cyclic AMP seems able to activate Ca2+ uptake in such a nonmitochondrial pool.

Adenosine Triphosphate↗
PubMed1991

Effectiveness of steroid treatment in myasthenia gravis: a retrospective study.

The records of 142 patients with generalized autoimmune myasthenia gravis who had been treated with steroids as the single immunosuppressive agent, collected at regular intervals, were employed for a retrospective evaluation. The effectiveness of treatment was assessed after 24 months; the data from the 6th and 12th months were also considered. After 24 months, 63.4% of the whole sample had improved (33.8% were in clinical or pharmacological remission); 13.4% were unchanged or had worsened and 22.3% had moved to a different immunosuppressive treatment. The rate of positive outcome was higher in patients over the age of 40 at disease onset.

Adolescent↗
PubMed1991

Evoked potentials monitoring of a cerebral focal ischemia model.

A model of cerebral ischemia by microsphere embolization in the rabbit was monitored with somatosensory evoked potentials by median nerve stimulation (SEPs) and by flash visual evoked potential (VEPs). The degree of SEP alterations paralleled the type of lesions (focal or multifocal ischemia or diffuse oedema). Alterations present at the first hour after ischemia were generally unchanged during the follow-up, which ended at the 24th hour. The prevalence of VEP alterations was low (only 16% in focal ischemia). These results are compared to EEG modifications performed in the same animals.

Animals↗