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Biomedical subjects

M Barbera

Publications and source records attributed to M Barbera.

17 recordsLinked to original sources
PubMed2005

Incidence of prostate cancer in Sicily: results of a multicenter case-findings protocol.

OBJECTIVE: To establish the incidence of prostate cancer (PCa) in Sicily in patients who entered an early detection protocol. METHODS: From February 2002 to February 2004, 16,298 subjects aged 40-75 entered the protocol. Patients with suspicious DRE, PSA>10 ng/ml, PSA<or=2.5 ng/ml, from 2.6 to 4 ng/ml or from 4.1 to 10 ng/ml with F/T PSA of <or=15%, <or=20% and <or=25% respectively underwent needle biopsy according to an extensive protocol. RESULTS: 3266 patients were eligible for biopsy; PSA was <or=4 in 12.7% and <or=10 ng/ml in 63.9% of patients. A PCa was found in 1171 cases (36.9%) with a relationship between PCa incidence and PSA and age respectively (chi2-test, p<0.0001); 51.8% of patients with PCa had a PSA<10 and 8.8% a PSA<4 ng/ml; 49% were clinically staged as T1c. The estimated odds ratios for each age group showed increased risk for PCa in the fourth decade with PSA between 2.6 and 4 ng/ml (12.5 times higher) and in the fifth decade with PSA between 4.1 and 10 ng/ml (6.2 times higher). CONCLUSIONS: Age and serum PSA levels are the major risk factors for PCa. On their basis it is possible to modulate the most suitable timing for early diagnosis in individual patients.

Adult↗
PubMed2001

Analysis of broadband x-ray spectra of highly charged krypton from a microcalorimeter detector of an electron-beam ion trap.

Spectra of highly charged Kr ions, produced in an electron-beam ion trap (EBIT), have been recorded in a broad x-ray energy band (0.3 keV to 4 keV) with a microcalorimeter detector. Most of the spectral lines have been identified as transitions of B- to Al-like Kr. The transition energies have been determined with 0.2% uncertainty. A semi-empirical EBIT plasma model has been created to calculate a synthetic spectrum of highly charged Kr and to determine a charge state distribution of Kr ions inside the EBIT.

Journal Article↗
PubMed2001

The Saccharomyces cerevisiae MUM2 gene interacts with the DNA replication machinery and is required for meiotic levels of double strand breaks.

The Saccharomyces cerevisiae MUM2 gene is essential for meiotic, but not mitotic, DNA replication and thus sporulation. Genetic interactions between MUM2 and a component of the origin recognition complex and polymerase alpha-primase suggest that MUM2 influences the function of the DNA replication machinery. Early meiotic gene expression is induced to a much greater extent in mum2 cells than in meiotic cells treated with the DNA synthesis inhibitor hydroxyurea. This result indicates that the mum2 meiotic arrest is downstream of the arrest induced by hydroxyurea and suggests that DNA synthesis is initiated in the mutant. Genetic analyses indicate that the recombination that occurs in mum2 mutants is dependent on the normal recombination machinery and on synaptonemal complex components and therefore is not a consequence of lesions created by incompletely replicated DNA. Both meiotic ectopic and allelic recombination are similarly reduced in the mum2 mutant, and the levels are consistent with the levels of meiosis-specific DSBs that are generated. Cytological analyses of mum2 mutants show that chromosome pairing and synapsis occur, although at reduced levels compared to wild type. Given the near-wild-type levels of meiotic gene expression, pairing, and synapsis, we suggest that the reduction in DNA replication is directly responsible for the reduced level of DSBs and meiotic recombination.

Alleles↗
PubMed2001

Dexamethasone-induced insulin resistance and pancreatic adaptive response in aging rats are not modified by oral vanadyl sulfate treatment.

OBJECTIVE: To explore the adaptive response of the endocrine pancreas in vivo and in vitro and the possible beneficial effect of the insulino-mimetic agent vanadyl sulfate (VOSO(4)), using glucocorticoid treatment to increase insulin resistance, in aging rats. DESIGN AND METHODS: Dexamethasone (Dex) (0.13 mg/kg b.w.) was administered daily for 13 days to 3- and 18-month old Sprague-Dawley rats and oral VOSO(4) was given from the 5th day. Plasma glucose, insulin and free fatty acids (FFA) concentrations were measured during these treatments and the insulin secretory response of the isolated perfused pancreas was assessed at the end of the experiment. RESULTS AND CONCLUSIONS: In both young and aging rats, particularly in the latter, hyperinsulinemia and increased in vitro insulin responsiveness to glucose were observed in response to Dex treatment, concomitant with an increase in plasma FFA concentrations. Thus, in glucocorticoid-treated animals, the beta-cell adaptive response occurred in both age groups and could possibly be mediated by increased circulating FFA; however, it was insufficient to prevent hyperglycemia in 60% of aging animals. Oral VOSO(4) administration failed to correct Dex-induced alterations in glucose and lipid metabolism, although it influenced in vitro beta-cell responsiveness to stimuli in aging rats.

1-Methyl-3-isobutylxanthine↗
PubMed1996

The oxytocin antagonist atosiban prevents androstenedione-induced myometrial contractions in the chronically instrumented, pregnant rhesus monkey.

We tested the hypothesis that increased oxytocin is a necessary mechanism for the mediation of androstenedione (delta 4A)-induced myometrial contractions by investigating the effects of maternal treatment with the oxytocin antagonist atosiban on in vivo delta 4A-induced contractions. In four monkeys (group I), maternal estradiol, oxytocin, and myometrial contractions were assessed at baseline and after continuous iv delta 4A administration. Similar measurements were made in three monkeys (group II) that received the same delta 4A infusion regimen, but in addition were treated daily with atosiban. Maternal estradiol and oxytocin levels and contractions were also assessed in four additional monkeys (controls; group III), in which the delta 4A vehicle, intralipid, was infused iv continuously. In group I, delta 4A induced myometrial contractions and increased maternal estradiol and oxytocin to term concentrations. No myometrial contractions occurred in group II monkeys after combined delta 4A and atosiban treatment despite estradiol being elevated to concentrations similar to those measured in group I monkeys. Atosiban had no effect on maternal heart rate or blood pressure. Maternal estradiol, oxytocin, and number of myometrial contractions remained unchanged from baseline values in control monkeys. In conclusion, oxytocin is a necessary part of the mechanisms mediating delta 4A-induced myometrial contractions. delta 4A promotes myometrial contractions via similar mechanisms that mediate spontaneous term contractions in pregnant monkeys.

Androstenedione↗
PubMed1993

Comparison of the myometrial response to oxytocin during daylight with the response obtained during the early hours of darkness in the fetectomized rhesus monkey at 160-172 days gestational age.

Six rhesus monkeys, fetectomized at 122-129 days gestational age (dGA), were studied to evaluate photoperiod-dependent differences in the myometrial sensitivity to exogenous oxytocin in the absence of a live fetus. One to two weeks before the study, at 150-162 dGA, sixteen maternal arterial samples were taken every 4 h to assess plasma concentrations as well as the presence of 24-h rhythmicity in plasma estradiol and cortisol. At 160-172 dGA, oxytocin was administered via the maternal inferior vena cava to elicit regular myometrial contractions. Each animal was studied twice: once during daylight and once during the early hours of darkness. Oxytocin was infused in a pulsatile fashion during the first minute out of every five over four consecutive 30-min intervals, during which the dose rate was increased after each 6-h oxytocin pulse (400, 800, 2000, and 4000 pg.kg-1.min-1). The overall response of the myometrium of the fetectomized animals, evaluated as the number of contractions per pulse of oxytocin, was higher during the daytime study (p = 0.006). The response to oxytocin in intact pregnant animals is greatest during the early hours of darkness. Comparison of the overall myometrial response of the fetectomized monkeys with the response of intact pregnant animals showed that the daytime responses were similar, but that the nighttime response of the fetectomized animals was significantly lower (p < 0.0002). These contrasting findings may be due to differences in the maternal neuroendocrine environment depending on the presence or absence of a fetal adrenal steroid contribution acting directly on the myometrium or acting indirectly through provision of precursors for estrogen formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Intraocular pressure during mechanical ventilation with different levels of positive end-expiratory pressure.

OBJECTIVE: To determine the effect of positive end-expiratory pressure (PEEP) on intraocular pressure. DESIGN: Prospective, controlled, longitudinal, dual center study. In one group, patients served as their own control. In the second group, isolated determinations of intraocular pressure were made in mechanically ventilated patients receiving PEEP. SETTING: Adult intensive care units of two university hospitals. PATIENTS: Intraocular pressures were measured serially in eight patients during the recovery phase of different clinical conditions and in 22 patients receiving mechanical ventilation with PEEP > or = 10 cm H2O for > 24 hrs. INTERVENTIONS: Group A) In eight patients, a PEEP dose-response curve was established (PEEP 0, 5, 10, 15, and 0 cm H2O every 15 mins). Intraocular pressures were measured at the end of each period. Group B) In 22 patients, measurement of intraocular pressures were done while the patients received mechanical ventilation with PEEP > or = 10 cm H2O for at least > 24 hrs. MEASUREMENTS AND MAIN RESULTS: In both groups, there was a positive correlation between the PEEP level and the central venous pressure (p < .05 in group A, and p < .03 in group B). No relationships between intraocular pressure and PEEP or central venous pressure were observed. However, there was a correlation between intraocular pressure and length of PEEP therapy (p < .03). We found ocular hypertension in only one patient (right eye intraocular pressure = 26 mm Hg; left eye intraocular pressure = 24 mm Hg). CONCLUSIONS: Short-term therapy with PEEP of < or = 15 cm H2O does not present a clinically important significant risk for intraocular pressure increase in a population with normal basal ocular tonometry. During prolonged mechanical ventilation with PEEP, increments in intraocular pressure may occur, but these increments appear to not be of a clinically relevant magnitude.

Adult↗
PubMed1978

Platelet aggregation following electrical stimulation.

It was demonstrated that the previous in vitro electrical stimulation of human and rat platelet-rich plasma does not modify the subsequent response of platelets to the aggregating activity of ADP, thrombin, thrombofax or adrenaline. This is interesting in view of the fact that the electrical stimulation can induce clot retraction.

Adenosine Diphosphate↗