PubMed Health⌕ Search

Biomedical subjects

M Benvenuti

Publications and source records attributed to M Benvenuti.

At least 19 recordsLinked to original sources
PubMed2004

Prevalence of HCV infection among health care workers in a hospital in central Italy.

Health care workers are at risk of acquiring transmissible diseases. Controversial results have been reported about HCV. The aims of the present study are to assess the prevalence of HCV in health care workers in Pistoia General Hospital (central Italy) and to compare prevalence with other groups, particularly with a sample of the general population. Serum samples collected from 511 health care employees engaged in direct clinical task and 222 clerical and nurse school attendees have been tested by ELISA and confirmed by RIBA. Total seroprevalence was 3.8%:4.7% in the first group; 1.8% in the second group. The data showed a slight increase in prevalence by age and not by length of stay in the health care workers' group. Comparison of HCV prevalence with blood donors from the province of Pistoia and the general population from Sersale (Catanzaro, southern Italy), restricted to under-40 subjects, indicates an increasing trend in this order: Blood donors, general population, clerical and nursing school attendees, health care workers' group with the highest value (3.4%). A cohort study is needed to evaluate pattern of HCV seroconversion.

Adult↗
PubMed1999

Encephalitis caused directly by Mycoplasma pneumoniae.

A case of non-fatal encephalitis in a 21-y-old immunocompetent woman is described. High titre serum antibodies against Mycoplasma pneumoniae were found. In addition, Mycoplasma pneumoniae DNA was detected in the cerebrospinal fluid by polymerase chain reaction. Neuroimaging findings by magnetic resonance and computed tomographic scanning of the brain, and laboratory investigations, including a search for serum antibodies to gangliosides, did not support an immune-mediated mechanism. No other pathogens were found. These results strongly suggest that the encephalitis was caused directly by Mycoplasma pneumoniae invasion of the central nervous system. They also indicate that such pathogenetic mechanism may sometimes be sufficient to explain neurological manifestations occurring during the course of Mycoplasma pneumoniae infection. The consequences for therapy are discussed.

Adult↗
PubMed1999

Crystallization and preliminary crystallographic analysis of the hydroxyquinol 1,2-dioxygenase from Nocardioides simplex 3E: a novel dioxygenase involved in the biodegradation of polychlorinated aromatic compounds.

Hydroxyquinol 1,2-dioxygenase (HQ1,2O) from Nocardioides simplex 3E, an enzyme involved in the aerobic biodegradation of a large class of chloroaromatic compounds such as 2,4-dichlorophenoxyacetate (2,4-D) and 2,4,5-trichlorophenoxyacetate (2,4,5-T), has been crystallized. HQ1,2O, which specifically catalyzes the intradiol cleavage of hydroxyquinol (1,2,4-trihydroxybenzene), an intermediate in the degradation of a variety of aromatic pollutants, to maleylacetate, has been recently purified to homogeneity. The enzyme is an homodimer composed of two identical subunits in a alpha 2-type quaternary structure, has a molecular weight of about 65 kDa and contains a catalytically essential Fe(III) ion. Crystals of HQ1,2O obtained using 2% PEG 400 and 2 M ammonium sulfate at pH 7.5 as precipitants belong to the orthorhombic space group P212121, with unit-cell parameters a = 81.15 (6), b = 86.79 (7), c = 114.93 (8). Assuming one dimer per asymmetric unit, the Vm value is 2.51 A3 Da-1. A complete native data set to 1.8 A resolution has been collected on a laboratory source. This is the first intradiol dioxygenase which specifically catalyzes the cleavage of hydroxyquinol to give diffraction-quality crystals.

Actinomycetales↗
PubMed1998

A one-million-year-old Homo cranium from the Danakil (Afar) Depression of Eritrea.

One of the most contentious topics in the study of human evolution is that of the time, place and mode of origin of Homo sapiens. The discovery in the Northern Danakil (Afar) Depression, Eritrea, of a well-preserved Homo cranium with a mixture of characters typical of H. erectus and H. sapiens contributes significantly to this debate. The cranium was found in a succession of fluvio-deltaic and lacustrine deposits and is associated with a rich mammalian fauna of early to early-middle Pleistocene age. A magnetostratigraphic survey indicates two reversed and two normal magnetozones. The layer in which the cranium was found is near the top of the lower normal magnetozone, which is identified as the Jaramillo subchron. Consequently, the human remains can be dated at approximately 1 million years before present.

Animals↗
PubMed1996

[Pulsating tumor of the sternum: enlarged exeresis and reconstruction with marlex-methylmethacrylate prosthesis].

The authors report on a rare case of pulsating tumor of the sternum. En bloc resection was carried out with removal of the sternal manubrium and body, tracts of the I-II-III rib with the intercostal muscles and part of the left pectoralis major. Reconstruction of the thoracic wall was performed with a marlex MMA sandwich prosthesis. From a histological viewpoint, the carcinoma was well differentiated and compatible with thyroid primitivity. Non complementary antiblastic therapies were provided as all the examinations carried out were negative and the intervention was radical. The patient had been followed-up with serial controls and three complete stagings at one, three and five years after intervention (CT, echography and function tests of the thyroid, bone scintigraphy). At follow-up of more than six years the patient is doing well and is event free. The authors believe, even with the help of reports from the literature that, in sternal metastases from thyroid carcinomas, especially when single and large, surgical therapy is required.

Carcinoma↗
PubMed1995

[Surgical stabilization of post-traumatic flail chest. Our experience with 116 cases treated].

The therapeutic approach in a patient with traumatic flail chest is varied and controversial, both as regards the type of treatment and as regards the surgical techniques to be employed. The authors have examined 116 cases of flail chest treated surgically; these represented 17.7% of the 655 chest traumas operated in the period from July 1975 to March 1993. Increasing experience has reduced indications for surgery: at present it is not performed in cases of serious craniocerebral lesions, of severe pulmonary contusions, or, however, when mechanical ventilation is required. As for surgical techniques, external traction was applied in the first 15 cases treated but then discontinued because of the poor outcome. Osteosynthesis (77 cases), associated with thoracotomy, was carried out with Kirschner wires, Vecsei metal plates, Judet agraffe, alone or variously combined. Recently, a less aggressive personal technique has been employed prevalently: Kirschner wires placed vertically within the chest, bridging between one rib (generally the V or VI, well fixed with metal plates), and the clavicle and/or sternum. The overall mortality rate, prevalently due to associated lesions, was 20.6%. Excluding emergencies, these patients should be operated in deferred emergency within 24-48 hours of trauma. Osteosynthesis, when indicated is the procedure offering the greatest assurance of success. The authors believe that, in selected cases, surgical stabilization is necessary.

Adolescent↗
PubMed1989

Synthesis and physicochemical characterization of a new material (PUPA) based on polyurethane and poly(amido-amine) components capable of strongly adsorbing quantities of heparin.

The synthesis of new materials (PUPAs) based on a commercial polyurethane and a heparin-complexing polymer, poly(amido-amine), was studied. PUPAs are capable of adsorbing heparin because the basic nitrogens of poly(amido-amine), once protonated, interact with the negative charges carried by the heparin molecule. Six different samples of PUPA were synthesized having a varied ratio of the components. The quantity of basic nitrogen on the surface and the bound heparin for each sample was determined. Two different kinds of heparin are present on a PUPA surface: one is strongly bound but can be detached by 0.1 M NaOH solution, the other is physically adsorbed and is slowly released by a stream of saline solution. A relationship between the quantity of strongly bound heparin and basic nitrogen was found. SEM and FTIR-ATR analysis were performed on all the PUPA samples. The mechanical characteristics change according to chemical composition.

Adsorption↗
PubMed1989

[Peroperative morbidity and mortality in thromboendarterectomy of the carotid bifurcation in patients with a previous stabilized stroke. Our results and review of the literature].

Carotid endarterectomy (CE), when performed in patients with previous stable stroke followed by complete or almost complete recovery, seems to be affected by a higher peroperative risk. From January 1982 to March 1988, we performed 230 CE in 207 patients, 188 (81.8%, Group 1) in patients with TIA or an asymptomatic plaque and 42 (18.2%, Group 2) in patients with previous strokes. The need for a temporary indwelling shunt has been evaluated with the measurement of carotid back pressure and, in the last 100 CEE, with the monitoring of somatosensory evoked responses (the shunt has however been used routinely anyway in the very first part of our experience). The incidence of carotid back-pressure values and of positive somatosensory evoked responses were similar in the two groups of C.E., even if the differences in the prealable evaluation were not statistically significant. The shunt has been nevertheless used more frequently in Group 2 (40.5 vs 28.2%). Statistical analysis has been performed with the chi 2 method. The incidence of permanent and transient neurologic deficits and of the peroperative mortality due to neurological and non-neurological causes was, respectively, 0.5, 2.6, 1.6, 0% (Group 1) and 2.4, 7.3, 2.4, 2.4% (Group 2) (non-significant). If we exclude the first 50 operations (in which technical and/or anaesthesiological problems may have influenced the neurological outcome of the patients operated upon), the previous values become, respectively, 0,07*, 0,7, 0% (Group 1) and 0, 5,5*, 0, 2,7% (Group 2) (*p less than 0,01, the only significant difference).(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Artery Diseases↗
PubMed1988

Value and limits of "critical auscultation" of neck bruits.

Within a group of 2,000 patients evaluated, most of them with symptoms of cerebrovascular insufficiency, 441 had a monolateral or bilateral cervical bruit. The 627 sides with an audible bruit were divided into main groups (A) symptomatic (TIA and/or stroke homolateral to the bruit), (B) possibly symptomatic (non-side-related symptoms), (C) asymptomatic (C1, in totally asymptomatic patients; C2, in patients with symptoms dependent on the hemisphere contralateral to the cervical bruit). Each patient was studied by means of clinical (history, blood pressure in both upper limbs, phonoendoscopic auscultation at various levels) and noninvasive instrumental examinations (CW Doppler spectrum analysis). An apparently primitive cervical bruit corresponded to a lesion of the carotid bifurcation in 61% of the cases (positive predictive value) whereas a normal bifurcation was detected in 70% of the cases in which the cervical bruit was considered as secondary (negative predictive value); the diagnostic accuracy of the "critical auscultation" has a value therefore of 63%, with a sensitivity of 84% and a specificity of 40%. The results obtained in the different groups of patients (symptomatic or asymptomatic) were not significantly different (chi-square). Even though maintaining the value of a cervical bruit as a sign of carotid stenosis or occlusion and consequently confirming the importance of neck auscultation, the authors conclude that the critical auscultation as commonly performed is not capable of excluding the presence of a carotid lesion with sufficient reliability, even in totally asymptomatic patients.

Auscultation↗
PubMed1987

Surface characterization of heparin-complexing poly(amido amine) chains grafted on polyurethane and glass surfaces.

Poly(amido-amine) chains grafted onto polyurethanes and glass form stable complexes with heparin yielding potential nonthrombogenic surfaces. The characterization of the surfaces, and the product of each chemical reaction including final heparinized surfaces, has been studied by contact angle data and scanning electron microscopy (SEM). Air in water, octane in water, and drop-on-plate contact angle data were used to estimate surface (gamma sv) and interfacial (gamma sw) free energies. Solid-water work of adhesion (Wa) and its dispersive (Wda) and polar (Ipsw) components were calculated for all studied surfaces. It has been found that the viscosity of polyurethane solution used for film casting influences wetting properties of these films. It has also been found that a direct correlation exists between the Ipsw/Wda values and the degree of coverage of the surfaces by cellular deposits after their exposure to platelet-rich plasma. Final heparinized polyurethane and glass materials are hydrophilic, their Ipsw/Wda ratio is high, and little or no cellular deposit is observed on their surfaces.

Biocompatible Materials↗
PubMed1987

Chemical and biological evaluation of heparinized poly(amido-amine) grafted polyurethane.

By a simple process poly(amido-amine) chains have been grafted onto the surface of polyurethane. The poly(amido-amine) was found to be able to complex heparin by electrostatic interaction. Heparin can be released only at pH greater than 10 with NaOH solution. The heparin adsorbing capacity of the material was biologically tested, and the anticoagulant activity of the heparinized polyurethane was demonstrated.

Adsorption↗
PubMed1987

A material (PUPA) presenting both the properties of polyurethanes and the capacity of adsorbing a high quantity of heparin.

Polyurethanes are widely used for biomedical applications, but there is still a constant search for improved blood-compatible materials. We studied a material (PUPA) obtained by the interconnection between a poly(amido-amine), N2LL, capable of forming stable complexes with heparin and a commercial polyurethane, Pellethane 2363-80AE, using hexamethylenediisocyanate as the crosslinking agent. The amount of absorbed heparin (evaluated by biological tests) was generally much higher than that found on the poly(amido-amine) surface-grafted polyurethane.

Adsorption↗