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Biomedical subjects

M Viviani

Publications and source records attributed to M Viviani.

At least 19 recordsLinked to original sources
PubMed2005

Polarization transfer in 4He(e-->,e'p-->)3H: is the ratio G E p/G M p ) modified in the nuclear medium?

Polarization observables in the (4)He(e-->,e'p-->)(3)H reaction are calculated using accurate three- and four-nucleon bound-state wave functions, a realistic model for the nuclear electromagnetic current operator, and a treatment of final-state interactions with an optical potential. In contrast to earlier studies, no significant discrepancies are found between theory and experiment both for the ratio of transverse to longitudinal polarization transfers and for the induced polarization, when free-nucleon electromagnetic form factors are used in the current operator. The present results challenge the current interpretation of the experimental data in terms of medium-modified form factors.

Journal Article↗
PubMed2005

Control of imported and acquired methicillin-resistant Staphylococcus aureus (MRSA) in mechanically ventilated patients: a dose-response study of enteral vancomycin to reduce absolute carriage and infection.

This study aimed to quantify the animate source provided by the patients using the concept of "absolute carriage" by multiplying the carrier rate by the level of carriage; and to compare the impact of a low and high dose of an oropharyngeal vancomycin gel on the absolute MRSA carriage and infection. In all, 265 patients were included, 126 were MRSA positive. Fifty-five patients received 2% vancomycin gel during the first year whilst 4% vancomycin gel was given to 50 patients during the second year. Surveillance swabs of throat and rectum were obtained from all eligible patients on admission and then twice weekly. The vancomycin protocol was started as soon as the surveillance cultures were positive for MRSA. Those patients received one gram of enteral vancomycin daily, divided into four doses. During the first year 2% vancomycin gel 4 ml (80 mg) was applied in the oropharynx in four doses in addition to the enteral solution (Group A). During the second year 4% vancomycin gel 4 ml (160 mg) was used (Group B). The absolute carriage was high during both periods: 3.6 for Group A, and 3.2 for Group B. The 4% vancomycin protocol significantly reduced the absolute carriage, compared to the 2% vancomycin protocol: 2.6 versus 1.5 (P < 0.01). Significant reduction in secondary endogenous infections was found in the second year: seven versus 15 patients (P < 0.05). A total of 3,588 microbiological samples were processed. Neither Staphylococcus aureus with intermediate sensitivity to vancomycin (VISA) nor vancomycin-resistant enterococci (VRE) were detected.

Administration, Rectal↗
PubMed2005

Systemic and organ dysfunction response during infusion of recombinant human activated protein C (rhAPC) in severe sepsis and septic shock.

AIM: The aim of this study was the assessment of the efficacy of recombinant human activated protein C (rhAPC) in septic patients. METHODS: A continuous observational prospective study on ICU patients with severe sepsis and septic shock was carried out. Applying the inclusion criteria of a national trial on the use of rhAPC, 15 patients (12 males and 3 females) were enrolled, mean age was 65.9 (SD 9.6), APACHE II score was > or =25. The following variables were assessed on 7 time-points (T1-T7): overall SOFA score; organ-specific SOFA score; APACHE II score; PCR, APTT, INR, fibrinogen, platelet count. Wilcoxon's statistical test and Spearman's correlation test (rho coefficient) between the SOFA and APACHE II scores were used. Test results with a P value below 0.05 were deemed significant. RESULTS: A significant correlation was identified between the APACHE II and SOFA scores. No significant change was found in Friedman's test and the respiratory, haematological and hepatic SOFA score, whereas cardiovascular, renal and neurological SOFA scores showed a significant trend between the ranks at the 7 time-points (chi2=14; df=6; P=0.029). During rhAPC treatment Friedman's test showed significant changes of PCR values over the 7 time-points (chi2=19.2; df=6; P=0.02). Wilcoxon's test indicated a significant decrease in the values recorded during the T2-T6 period. On day 28, 12 of the 15 patients originally enrolled were still alive. Mortality rate was therefore 20% (CI 95%). CONCLUSIONS: RhAPC is the first biological agent approved for the treatment of severe sepsis and septic shock. Our experience is confined to patients with severe sepsis and septic shock, and some severity indexes showed a modulation of the inflammatory processes and haemostatic balance, 2 factors which play a key role in the evolution of sepsis and organ dysfunction.

APACHE↗
PubMed2003

Candida colonization in patients with esophageal disease: a prospective clinical study.

The incidence of Candida infection has significantly increased over the recent years, becoming the fourth most common pathogens isolated in patients admitted to intensive care units (ICU). Mortality rates ranging between 6 and 38% have been reported to be associated with candidemia. Esophageal surgery may increase the risk of systemic Candida infection in critical patients requiring postoperative ICU admission. The aim of the present study was to assess the prevalence of Candida colonization in patients with esophageal disease undergoing surgery. Between April 1999 and April 2001, 131 patients with esophageal disease and 40 healthy volunteers were prospectively tested for Candida colonization by oral and pharyngeal swab. Candida colonization was significantly more frequent in patients with esophageal disease than in control subjects (38.9 vs 7.5%, P < 0.01); the prevalence was higher in individuals with carcinoma than in those with benign disease (51.8 vs 24%, P < 0.02), and in patients undergoing neoadjuvant chemoradiation therapy compared to those having primary surgery (55.5 vs 34.4%, P < 0.01). These data suggest that Candida colonization of the gastrointestinal tract is common in patients with esophageal disease. Pharmacological attempts to prevent or reduce the magnitude of this event may be worthwhile before surgery. However, the hypothesis that antifungal oral prophylaxis with nonabsorbable drugs may lower the incidence of candidemia in patients with gastrointestinal Candida colonization, especially in those candidates to postoperative ICU admission, should be tested by randomized double-blinded studies.

Adenocarcinoma↗
PubMed2001

Precision measurement of the spin-dependent asymmetry in the threshold region of 3He(e, e').

We present the first precision measurement of the spin-dependent asymmetry in the threshold region of 3He(e,e') at Q2 values of 0.1 and 0.2 (GeV/c)2. The agreement between the data and nonrelativistic Faddeev calculations which include both final-state interactions and meson-exchange current effects is very good at Q2 = 0.1 (GeV/c)2, while a small discrepancy at Q2 = 0.2 (GeV/c)2 is observed.

Journal Article↗
PubMed2001

The A(y) problem for p-3He elastic scattering.

We present evidence that numerically accurate quantum calculations employing modern internucleon forces do not reproduce the proton analyzing power, A(y), for p- 3He elastic scattering at low energies. These calculations underpredict new measured analyzing powers by approximately 30% at E(c.m.) = 1.20 MeV and by 40% at E(c.m.) = 1.69 MeV, an effect analogous to a well-known problem in p-d and n-d scattering. The calculations are performed using the complex Kohn variational principle and the (correlated) hyperspherical harmonics technique with full treatment of the Coulomb force. The inclusion of the three-nucleon interaction does not improve the agreement with the experimental data.

Journal Article↗
PubMed2000

Realistic calculation of the 3He + p (hep) astrophysical factor.

The astrophysical factor for the proton weak capture on 3He is calculated with correlated hyperspherical harmonic wave functions corresponding to a realistic Hamiltonian consisting of the Argonne v(18) two-nucleon and Urbana-IX three-nucleon interactions. The nuclear weak current has vector and axial-vector components with one- and many-body terms. All possible transitions connecting any of the p 3He S- and P-wave channels to 4He are considered. The S factor at a p 3He center-of-mass energy of 10 keV is predicted to be 10. 1x10(-20) keV b, a factor of approximately 4.5 larger than the value adopted in the standard solar model. The P-wave transitions are found to contribute about 40% of the calculated S factor.

Journal Article↗
PubMed2000

An uncommon cause of lower limb weakness.

We describe a case of a severely mentally disabled patient diagnosed as suffering from Guillain-Barré syndrome and treated with repeated plasma exchange. However, the abrupt onset of a cardiovascular collapse prompted a more in-depth diagnostic workup which demonstrated that the neurologic symptoms were likely to be ascribed to poisoning with heavy metals from a large number of ingested coins and other metallic items.

Aluminum↗
PubMed1999

Does the length of stay in the intensive care unit influence the diagnostic accuracy? A clinical-pathological study.

To evaluate the rate of diagnostic errors leading to preventable deaths among patients admitted to our intensive care unit (ICU), we retrospectively reviewed the medical and autopsy records of all patients who died in the ICU between 1 January 1991 and 31 December 1993. Excluded were patients with traumatic injuries, cerebrovascular accidents and primary cardiac arrest. According to their length of stay (LOS) in the ICU, patients were subdivided into Group A (LOS 0-24 hours), Group B (LOS > 24 hours-14 days), and Group C (LOS > 14 days). Errors were divided into Type 1 (failure to recognize a treatable life-threatening condition); Type 2 (failure to recognize a life-threatening condition, which treated, however, would unlikely alter the outcome), and Type 3 (failure to recognize a condition unrelated to the outcome). Overall, 159 consecutive patients were enrolled. Type 1 errors were 5% in Group A, 4% in Group B and 9% in Group C. Type 2 errors were 18% in Group A, 34% in Group B, and 30% in Group C. Fully correct diagnoses or Type 3 errors were present in 77% of patients in Group A, 62% of patients in Group B, and 61% of patients in Group C. Clinical errors of any type were not related with the LOS in the ICU or in the hospital, age and the number of underlying chronic diseases.

Adult↗
PubMed1998

[Leptospirosis. Description of a clinical case and review of the literature].

Leptospirosis is a world-wide diffused anthropozoonosis due to many strains of Leptospira. Initial symptoms may be mild, although in many cases severe systemic symptoms, including high fever, hypotension, etc. may be present since the beginning. In these latter circumstances, the diagnosis of leptospirosis can be very difficult because of the complexity of clinical picture especially when the history is lacking or incomplete. A case report of a 45 year-old man admitted to the hospital after severe jaundice and fever of unknown origin associated to altered mental status, renal failure and hypoxemia is presented. Because of the presence of septic shock and severe respiratory failure, the patient was transferred to the intensive care unit. The diagnostic hypothesis, based on clinical history, was confirmed by laboratory tests (leptospiral IgM antibodies detection). Therapeutical approach with the use of selected antibiotics (penicillin 24,000,000 U for day) and therapy of septic shock led to improvement of the patient's clinical conditions who was then transferred to a regular medical ward.

Humans↗
PubMed1996

Traumatic blunt carotid injury: clinical experience and review of the literature.

To evaluate the symptoms, the associated lesions, the treatment and the outcome of patients with blunt carotid injury (BCI), we reviewed the records of all patients admitted to our intensive care unit with head trauma between May 1991 and May 1995. A patient's assessment included the commonly used severity scores and cranial computed tomography (CT). Other diagnostic investigations were performed according to the clinical setting. Four patients (2 males, 2 females, age 29 +/- 13 years) out of 145 were diagnosed to have BCI. At admission, the Glasgow Coma Scale (GCS) was > or = 12 in all patients, and was associated with hemiparesis in three of them; the fourth became paretic 48 hours later. No pathological elements were demonstrated at the initial CT scan, whilst subsequent examinations showed signs of ischaemia after a variable interval from admission. In every patient the radiologic investigations demonstrated a thrombotic obstruction of the internal carotid artery (ICA), associated with an intimal dissection in two cases. Three patients were discharged with only minor neurologic symptoms. The fourth patient was referred to our ICU after the development of a massive hemispheric infarction, and died 3 days after admission.

Adolescent↗
PubMed1996

[Use of the laryngeal mask in general anesthesia. Clinical experience].

GOAL OF THE STUDY: To evaluate the use of the laryngeal mask during general anesthesia. STUDY DESIGN: We prospectively studied patients undergoing surgery with general anesthesia in spontaneous breathing. ENVIRONMENT: Urologic and general surgical ward, with standard monitoring equipment. PATIENTS: We studied consecutively 100 patients (ASA 1-3, 80 males, 20 females, age 64 +/- 15 years, range 19-98 years); 59 patients had a preexisting cardiopulmonary or metabolic disease. Monitoring included ECG, the arterial pressure (noninvasive), the CO2 capnography (EtCO2), the pulsossimetry (SpO2), the respiratory rate (RR) and the tidal volume/kg (TVi). The double product (DP = heart rate X systolic arterial pressure) was used as an index of cardiac stress. These parameters were recorded at 10-minute intervals throughout the procedure. RESULTS: The heart rate, the systolic arterial pressure remained stable during the anesthesia, whereas the DP significantly decreased at t10, t20, t30 and t40. The EtCO2 decreased slightly (from 41 +/- 6 to a 36 +/- 4 mmHg; p.n.s.), SpO2 did not change (from 97 +/- 2% to 96 +/- 2%; p:n.s.). The RR significantly increased at t30 and t40 and the TVi significantly increased during the first hour. No relevant complications have been reported. CONCLUSIONS: Anesthesia with laryngeal mask was not associated with any detrimental cardiovascular and respiratory effect.

Adult↗