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Biomedical subjects

A Baroni

Publications and source records attributed to A Baroni.

At least 55 records · Page 3Linked to original sources
PubMed1994

Properties of Yersinia enterocolitica porins: interference with biological functions of phagocytes, nitric oxide production and selective cytokine release.

We have extracted and purified Yersinia enterocolitica ATCC 9610 porins that have molecular weights of 36-38 kDa. They inhibited phagocytosis and phagosome-lysosome fusion (30%) in human monocytes and caused enhanced nitrite production. Preincubation of polymorphonuclear neutrophils with porins (1-10 micrograms/ml/10(6) cells) induced a reduction in chemotaxis, adherence to nylon wool and chemiluminescence. Human lymphomonocytes treated with Y. enterocolitica porins showed a distinctive cytokine profile. Interleukin-1 alpha, interleukin-6 and tumour necrosis factor alpha were released within 3-6 h, while interleukin-8, gamma interferon and granulocyte-macrophage colony stimulating factor were released after 18 h. Interleukin-3 and interleukin-4 were not detected at up to 48 h of incubation. In conclusion, these immunomodulating and histotropic properties may account for Y. enterocolitica infection and its sequelae.

Chemotaxis↗
PubMed1994

[Cost methodologies in dialysis in relation to the Italian National Health Service].

This work analyses the economic aspects of dialysis in Italy in relation to government resources allocated to the health service in general. The authors illustrate the procedures used to estimate the resources required by the dialytic programme. The costs of dialytic programmes in different cities and at different periods in the history of the Italian health service are compared. A concrete example is outlined of the economic management of dialysis and the authors demonstrate how the results were obtained using cost analysis.

Health Care Costs↗
PubMed1993

Outer-membrane porins from gram-negative bacteria stimulate platelet-activating-factor biosynthesis by cultured human endothelial cells.

Porins are a family of hydrophobic proteins located in the outer membrane of the cell wall in Gram-negative bacteria. The effect of porins on the biosynthesis of platelet-activating factor (PAF) by cultured human umbilical-cord-vein-derived endothelial cells (HUVEC) was investigated. The results demonstrate that porins were able to induce a dose-dependent synthesis of PAF in HUVEC. PAF, synthesized after stimulation with porins, was mainly cell associated and the synthesis peaked at 15 min, decreasing rapidly thereafter. Experiments with radiolabeled precursors demonstrated that PAF, a 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine, was synthesized via the remodeling pathway involving the acetylation of 1-O-alkyl-2-lyso-sn-glyceryl-3-phosphorylcholine (2-lysoPAF) generated from 1-O-alkyl-2-acyl-sn-glyceryl-3-phosphorylcholine by phospholipase-A2 activity. The activation of phospholipase A2 in HUVEC stimulated by porins was detected by observing the mobilization of [14C]arachidonic acid. In addition, the activity of acetyl-CoA:1-alkyl-sn-glycero-3-phosphorylcholine 2-O-acetyltransferase was transiently increased in porin-stimulated HUVEC and, after incubation with [3H]CoASAc or [3H]acetate, the [3H]acetyl group was incorporated into newly synthesized PAF. Porins, by forming transmembrane channels, induced a sustained influx of extracellular 45Ca2+ into the cytosol. The activation of PAF synthesis by porins depended on this influx rather than on intracellular calcium mobilization, since PAF synthesis did not occur in the absence of extracellular Ca2+.

Acetyltransferases↗
PubMed1993

Relationship between health status, fluid intelligence and disability in a non demented elderly population.

This study examines the impact of overall health status and common chronic medical conditions on cognitive performance in an older population and the effect of poor cognitive performance on functional disability. The study population consisted of 485 subjects who were 77 and 78 years old, and residing in district No. 6 of the city of Florence; all participants underwent a structured interview to collect information on demographics, education, physical health, disability, and cognitive status. Data from 94 subjects, who were previously diagnosed as affected by dementia or other conditions known to be direct causes of cognitive impairment, and from 6 subjects, who scored less than 20 in the Mini-Mental State Examination, were excluded from the analysis. The number of chronic conditions, drugs used, contacts with the physician, days in bed, and days of hospitalization in the last 6 months were considered as indicators of physical health. Functional disability was assessed evaluating both ADLs and IADLs. The Mini-Mental State and the "Blocks" test, a component of the Wechsler Adult Intelligence Scale Revised, were used for the assessment of cognitive status. After adjusting for the level of formal education, physical health status and several specific chronic conditions were predictors of cognitive performance. A significant association was found between a low "Blocks" test score and a decreased level of functional status. In a multivariate model, better performance on the "Blocks" test was associated with a higher score in the disability scale. This association was independent of the effect of education. The results suggest that in the elderly, poor health status is associated with a cognitive impairment that can be measured by the "Blocks" test. However, the role of this association in the pathway from disease to disability remains unclear.

Activities of Daily Living↗
PubMed1993

Recovery of functional status after stroke. A postrehabilitation follow-up study.

BACKGROUND AND PURPOSE: Information on predictors of long-term change in functional capacity after a rehabilitation program in stroke patients is scant. This study describes the long-term evolution of self-reported functional ability after discharge from rehabilitation and its relation with age, level of neural impairment at discharge, and changes in neural impairment during follow-up. METHODS: Fifty patients (31 men and 19 women; mean +/- SD age, 66.0 +/- 9.9 years; range, 47-86 years) with a first unilateral stroke and no severe cognitive impairment were consecutively enrolled. Self-reported disability in activities of daily living and neural impairment measured by the Fugl-Meyer Scale were evaluated after discharge from a rehabilitation program and 3 and 6 months later. RESULTS: Functional disability was significantly reduced after 3 and 6 months. Attenuation of disability occurred mainly among those patients with more severe baseline neural impairment. In this group, patients aged > or = 65 years were more disabled at baseline than younger individuals, but they had the same rate of improvement. In patients aged < 65 years, changes in disability over time could be attributed to changes in neural function, whereas older patients' functional recovery was greater than that expected from their improvement in neural impairment alone. CONCLUSIONS: These results suggest that in stroke patients with severe neural damage further functional improvement occurs even after completion of a rehabilitation program. There is evidence that older patients may be more likely to employ compensatory strategies to overcome some of the neural impairment that remains after stroke.

Activities of Daily Living↗
PubMed1992

Salmonella typhimurium porins stimulate platelet-activating factor synthesis by human polymorphonuclear neutrophils.

Porins, a family of hydrophobic proteins located in the outer membrane of cell-wall of Gram-negative bacteria, were shown to stimulate the synthesis and release of platelet-activating factor (PAF), a 1-O-alkyl-2-acetyl-sn-glycerol-3-phosphorylcholine mediator of inflammation and endotoxic shock produced by polymorphonuclear neutrophils. PAF synthesis was independent either from contamination by LPS or generation of TNF. Experiments with labeled precursors demonstrated that PAF was synthesized via the remodeling pathway that involves acetylation of 1-O-alkyl-sn-glyceryl-3-phosphorylcholine generated from 1-O-alkyl-2-acyl-sn-glyceryl-3-phosphorylcholine by phospholipase A2 (PLA2) activity. Porins, indeed, induced a sustained PLA2-dependent mobilization of [14C]arachidonic acid that was inhibited by p-bromodiphenacylbromide. p-Bromodiphenacylbromide, an inhibitor of PLA2, also blocked PAF synthesis by preventing the mobilization of 2-lyso-PAF, the substrate for PAF-specific acetyltransferase. The addition of 2-lyso-PAF restored PAF synthesis. The activity of acetyl CoA:2-lyso-PAF acetyltransferase was transiently increased in porin-stimulated PMN and the [3H]acetyl group was incorporated in the synthetized PAF after cell preincubation with [3H]acetyl CoA. The activation of PAF synthesis by porins as well as its release were dependent on extracellular Ca2+. Porins by forming trans-membrane channels determined a sustained influx of 45Ca2+ into the cytosol. As shown by inhibitors of Ca(2+)-calmodulin complexes, calmodulin mediated the Ca(2+)-dependent activation of enzymes involved in PAF synthesis.

Arachidonic Acid↗
PubMed1992

Effective population size of a rural village on a large plain (Veggiano, Padua, Italy).

A small municipality of about 2,000 inhabitants on a large plain (that of the river Po, which flows across the whole of Northern Italy) was chosen as a model to study the level of genetic isolation of a population which is not delimited by clear geographical barriers. Wright's treatment of isolation by distance was considered to be applicable to this case. Estimates of the non-random component of inbreeding and of the immigration rate in the past showed that, despite the deeply rural environment, the population turnover in the area was extremely rapid. Although the parameter estimates were computed on the basis of little direct empirical evidence, it was concluded that the effective population size was at least one order of magnitude larger than might appear when considering the total population size of the municipality.

Consanguinity↗
PubMed1992

Anesthetic agents induce human mononuclear leucocytes to release cytokines.

Studies were carried out on the ability of some anesthetic agents (Propofol, Dormicum, Ketalar and Penthotal) to induce the release of cytokines by human monocytes and lymphocytes in vitro. All anesthetic agents tested at hematic concentrations reached during anesthetic administration cause an increase in the production of Tumor necrosis factor (TNF) from human monocytes; the increase is 4-5 times greater than controls. The greatest Interleukin -1 alpha (IL-1 alpha) production increase was induced by Propofol. The release of Interleukin -6 (IL-6) is notably increased by Ketalar (about 10 times greater than controls). In the presence of different anesthetic agents, human lymphocytes release Interleukin -4 (IL-4) and Interferon gamma- (IFN-gamma). Penthotal and Ketalar increase IL-4 production which appears quite high compared to that obtained with Con A used as standard challenge. Propofol induce IL-4 release which is about the same as that seen with Con A. IFN-gamma is released in high quantities by lymphocytes treated with Propofol. Dormicum, Ketalar and Penthotal induce non-significant increase of IFN-gamma release. The results concern the choice of anesthetic, in relation to its action on host immune response. This aspect is particularly interesting in immunocompromised host.

Anesthetics↗
PubMed1992

Antimicrobial agents induce monocytes to release IL-1 alpha, IL-6, and TNF, and induce lymphocytes to release IL-4 and TNF tau.

Evaluation was carried out on the action of different antibiotics on the release of cytokines. Experiments were done in vitro on monocytes and on human lymphocytes. Results show that the majority of the antibiotics tested are able to induce the release of one or more cytokines from their respective producing cells. Among the beta-lactams the most active were the cephalosporins (cephalexin, cefamandol, ceftazidin, and a sulbactam-ampicillin combination) in inducing the release of TNF, IL-1 alpha, and IL-6 from monocytes, and releasing IL-4 and IFN-tau from lymphocytes. The sulbactam-ampicillin combination and cefamandole were extremely active in the production of IFN-tau. Among the lincosamides, clindamycine notably stimulated the release of TNF and IL-6, while lincomycine induced a notable increment of IL-4 from monocytes. Teicoplanin is a very strong inducer of TNF, IL-1 alpha and IL-6.

Anti-Bacterial Agents↗
PubMed1991

Value of combined assessment of physical health and functional status in community-dwelling aged: a prospective study in Florence, Italy.

A survey of the health and social conditions of a representative sample of 967 persons aged 60 years and older from the city of Florence, Italy, was undertaken in 1980. In 1987, a follow-up survey of this cohort was performed. There were 391 documented deaths, 408 survivors, and 168 individuals who could not be located. Functional ability at baseline was assessed using a World Health Organization 14-item scale. Indicators of physical health status included chronic disease status, number of drugs, physician visits, and days of hospitalization. After adjustment for age and sex, both functional ability and indicators of physical health status were found to be independent, statistically significant predictors of mortality. The results of this study further support the view that biomedical and functional assessment are both necessary for a comprehensive evaluation of the older population.

Activities of Daily Living↗
PubMed1989

[Spatial identification of an excess of cerebral tumors in a highly industrialized small area: results of a case-control study].

A case-Control Study for the association between Central Nervous System Malignancies and residence in a small area within the municipality of Campi Bisenzio (Florence, Italy) has been performed following a spontaneous reporting of three cases of brain cancer. All incident cases of SNC tumours diagnosed in the period 1973-82 with histological or radiological confirmation among residents in the study area are recruited as cases. Five controls for each case, matched by sex and age (+ - 1 year), are randomly chosen from demographic files in the municipality. The residential history for each subject enrolled in the study is recorded from the same demographic files. The relative risk for ever resident in the 46-50 electoral sections relative to never resident was 7.33 (C.I. 95% 2.6-20.3). A trend for duration of residence was also relevant (less than 5 years RR = 2.1, 5-10 years RR = 8.4, more than 10 years RR = 11.3; chi-square for trend = 41 p = 0.00002).

Adolescent↗
PubMed1988

Flunarizine-induced parkinsonism in the elderly.

Twenty-seven patients (19 women and 8 men, ages 63 to 88 years; mean, 74 years) displayed mild to moderate parkinsonism and altered ballistic motor performances during long-term flunarizine treatment. One month after, flunarizine withdrawal, 20 patients showed clear-cut improvements in both clinical features and ballistic motor performances; a complete recovery within 6 months was observed in all these patients but one, who still showed very mild slowness of movement. On the other hand, seven patients showed little clinical improvement and still maintained markedly altered ballistic motor performances 1 month after drug withdrawal. At the 2-month follow-up assessments, either they did not improve further or they deteriorated; they were successfully treated with L-dopa and, despite the ameliorations, after 12 to 24 months they still have definite parkinsonian syndrome. The authors conclude that (1) flunarizine, even at the recommended dose (10 mg daily), can induce reversible parkinsonism, at least in subjects older than 60; (2) the persistence of a marked symptomatology 2 months after flunarizine withdrawal should lead to starting treatment with antiparkinsonism drugs; (3) the study of ballistic movements is proposed as a useful tool for objective quantification and early detection of bradykinesia.

Aged↗
PubMed1988

Effects of expected perturbations on the velocity control of fast arm abduction movements.

A triphasic electromyographic pattern of sequential activation of agonist, antagonist, and again agonist muscles underlies rapid or ballistic limb movements in humans. The first agonist burst reflects muscular force accelerating the limb, the antagonist burst is mainly related to the braking process of movement, while the second agonist burst is considered a reactive adjustment to the deceleration. The duration of the first agonist burst has been reported to be constant for movements of different amplitudes, thus suggesting that only changes in its amplitude contribute to the velocity control of movement. The present research has been undertaken to investigate the strategy whereby the nervous system increases agonist impulsive force for ballistic performance in response to experimental conditions requiring perceptual and/or provisional processes related to expected changes in load or accuracy constraints. The effects of expected perturbations of different strengths on some kinematic and electromyographic variables of fast arm abduction movements performed in a step-tracking task and in an outer-stop terminated task were analyzed in normal subjects. All motor performances were characterized by triphasic electromyographic patterns. In the absence of expected perturbations, the mean velocity of the movements was markedly higher in the outer-stop terminated task. Correspondingly, greater amplitudes and durations of the first agonist burst were observed. In both types of motor tasks, when expected perturbations were inserted, the velocity of the movement increased as well as the amplitude and the duration of the first agonist burst. These results, in agreement with previous observations, indicate that the normal mechanism, whereby the nervous system increases agonist impulsive force in rapid movements, comprises changes not only in the amplitude but also in the duration of the first agonist burst.

Adult↗
PubMed1984

Human ballistic arm abduction movements: effects of L-dopa treatment in Parkinson's disease.

In patients with Parkinson's disease who had never previously been treated with any antiparkinsonism drug, we studied the effects of L-dopa on ballistic arm abduction movement in a step-tracking task. L-Dopa treatment increased the mean velocity of the initial movement towards the target without loss of accuracy and with improved motor performance under open-loop conditions. Performance also improved in motor tasks with expected perturbation. EMG patterns of arm abduction movements showed abnormal features in untreated patients and improved after L-dopa treatment.

Adult↗
PubMed1981

[Age-related changes in some spatial-temporal parameters of ballistic movement in man].

Age-related changes in spatio-temporal parameters of ballistic arm abduction movements were investigated in two groups of healthy volunteers: a group of younger subjects (aged 20-45 years) and a group of older subjects (aged 60-82 years). Arm abduction was performed in a step-tracking task. Older subjects exhibited longer reaction times, greater durations of the initial movement together with lower mean velocities. Accuracy, however, did not significantly differ from that of younger subjects. No differences were found both in the number and in the accuracy of "ballistic" movements, i.e. those completed within one mean reaction time or less. In motor tasks including slight expected perturbations during the movement, the motor performance of all tested subjects was not impaired. Furthermore, older subjects displayed a decrease in the duration of the initial movement and an increase of its mean velocity, without changes in accuracy; the increase of mean velocity became significant under visual closed-loop conditions. The results suggest that only some features of bradykinesia are age-related. Older subjects appear to retain a normal strategy for ballistic movement: the neural mechanisms controlling the generation of sufficient accelerative forces and of the appropriate timing for ballistic movements seem to be poorly activated rather than disrupted, since they may recover under specific circumstances.

Adult↗