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Biomedical subjects

M Marconi

Publications and source records attributed to M Marconi.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Current therapeutic approaches of neurologic damage in neonatal asphyxia].

Perinatal hypoxiaischaemia is a major cause of mortality and neurological sequelae in term newborn. Modulation of mechanisms leading to brain cell death, in the so-called therapeutic window, may reduce apoptosis and necrosis. Oxidative stress and newborn resuscitation, early postnatal pharmacological treatment and hypothermic neuroprotection are described. Additional controlled prospective trials are warranted on newborns. A combination of neuroprotective agents with synergistic effects could represent a potential treatment strategy.

Animals↗
PubMed2000

Long term persistence of anti-HBs protective levels in young patients with type 1 diabetes after recombinant hepatitis B vaccine.

The aim of the present study was to evaluate the persistence of anti-hepatitis B protective levels in young patients with type 1 diabetes, successfully immunised with a recombinant hepatitis B vaccine. We re-evaluated, after a 4 year follow-up, 54 patients and 70 age and sex-matched healthy subjects. Protective antibodies levels were found in 50/54 (92%) patients and in 67/70 (96%) controls. Moreover, anti-HBs levels were similar in diabetic patients and controls (means of log-titre and (sd); 1.95 (0.88) and 2.18 (0.64) patients and controls, respectively; P=0.11). No cases of clinical hepatitis were reported and all patients and controls remained HBc negative. These data demonstrate the persistence of anti-HBs levels in children, adolescents and young patients with type 1 diabetes after recombinant hepatitis B vaccine showing evidence of longterm immunogenity and protective effect.

Adolescent↗
PubMed2000

The RR Lyrae Star U Comae as a Test for Nonlinear Pulsation Models.

We use high-precision multiband photometric data of the first-overtone RR Lyrae star U Comae to investigate the predictive capability of full-amplitude, nonlinear, convective hydrodynamical models. The main outcome of this investigation is that theoretical predictions properly account for the luminosity variations along a full pulsation cycle. Moreover, we find that this approach, because of the strong dependence of this observable and of the pulsation period on stellar parameters, supplies tight constraints on stellar mass, effective temperature, and distance modulus. Pulsational estimates of these parameters appear in good agreement with empirical ones. Finally, a well-defined bump just before the luminosity maximum gave the unique opportunity to calibrate the turbulent convection model adopted for handling the coupling between pulsation and convection.

Journal Article↗
PubMed2000

Increasing transfusion safety by reducing human error.

Transfusion of the wrong blood is a rare but measurable event that may result in serious complications and whose main cause is human error. Any preventive strategy should be based on a careful assessment of the incidence of these events and of their causes, and requires a standardized confidential reporting system, to avoid underreporting, covering also near misses. Creating or revising written procedures and monitoring their implementation are indispensable to improve blood safety, but human error can occur in spite of these measures. Technologic instruments are now available to fill the gap between written and implemented procedures, forcing the operator to carry out the critical steps in the process according to the adopted guidelines.

Humans↗
PubMed2000

Improving transfusion safety by electronic identification of patients, blood samples, and blood units.

To evaluate the feasibility of using an electronic identification system to improve safety and documentation of blood transfusions, a hand-held bar code scanner and data terminal, portable label printer, and related software were integrated into all phases of the blood transfusion process, including sample collection, laboratory testing, and administration of blood components. The study was conducted in two hospitals, one in Italy and the other in the United States. Each hospital used different laboratory analysers and information systems. A total of 621 blood components were transfused to 177 patients using 331 blood samples with 100 percent accuracy and electronic documentation of all pertinent patient, staff, sample, testing, and component information. Bar code reading and related electronic technology can be adapted to improve transfusion safety and reduce the risk of human errors at all steps of the blood transfusion process.

Journal Article↗
PubMed1999

Pyrrolo[3,2-c]quinoline derivatives: a new class of kynurenine-3-hydroxylase inhibitors.

A series of pyrrolo[3,2-c]quinoline derivatives were synthesised and evaluated as inhibitors of selected enzymes of the kynurenine pathway. 7-Chloro-3-methyl-1H-pyrrolo[3,2-c]quinoline-4-carboxylic acid (7a) was found to be a relatively potent and selective inhibitor of kynurenine-3-hydroxylase (KYN-3-OHase). A molecular modelling study showed a good superimposition of 7a with PNU-156561 and kynurenine the natural substrate of KYN-3-OHase.

Animals↗
PubMed1999

Brain concentrations of kynurenic acid after a systemic neuroprotective dose in the gerbil model of global ischemia.

1. Kynurenic acid (KYNA) is a kynurenine metabolite and a broad spectrum excitatory amino acid antagonist that has been shown to be neuroprotective in models of cerebral ischemia, when administered exogenously. However, the actual concentration required in the CNS to evoke significant neuroprotection has never been assessed. 2. The purpose of this study was to address this question in the gerbil model of forebrain ischemia. KYNA (400-1600 mg/kg) or vehicle were administered i.p. 15 min before 5 min bilateral carotid occlusion. 3. Seven days after reperfusion, ischemia-induced hippocampal nerve cell loss (95% in vehicle-treated) was significantly lower in KYNA-treated gerbils (65% and 52% at 1000 and 1200 mg/Kg, respectively, P < 0.01). Treatment with 1000 mg/kg produced brain KYNA concentrations that were dramatically elevated (135.9 and 42.3 microM in CSF and whole brain, vs 0.032 and 0.16 microM in controls, at 15 min after ischemia), as measured in a separate group of transcardially-perfused gerbils. Cerebral KYNA concentrations tended to return to basal values 2 hours after reperfusion. 4. These results indicate that KYNA has a marked neuroprotective effect in a model of forebrain ischemia. This activity is associated with KYNA concentrations in the brain and CSF that are compatible with the in vitro affinity of the compound for ionotropic glutamate receptors.

Animals↗
PubMed1998

G-CSF after autologous hemopoietic stem cell transplantation in malignant lymphoma.

Forty-eight autografted patients were studied after treatment with granulocyte-colony stimulating factor (G-CSF) and were compared with a historical series of 24 patients autografted with bone marrow (BM) without G-CSF. When the patients were divided on the basis of G-CSF administration, type of lymphoma and the source of hemopoietic stem cells, no significant difference was found in the median number of infused BM cells, duration of febrile episodes, platelet and hemoglobin recovery, or in the number of transfusions. The patients receiving peripheral blood (PB) + G-CSF had significantly shorter median durations of antibiotic therapy, hospital stay and polymorphonucleate (PMN) recovery. When the Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL) cases were considered separately, a significant difference between those receiving and those not receiving G-CSF was observed only in the HD group. The advantage offered by PB + G-CSF over BM + G-CSF was far more evident in the NHL group than in HD. It can be concluded that G-CSF improves the outcome of BM transplant in HD, and that the use of PB + G-CSF adds a further advantage; conversely, in NHL, PB + G-CSF is strikingly superior to BM + G-CSF, but the addition of G-CSF adds little advantage.

Adolescent↗
PubMed1998

IL-10 and IL-4 co-operate to normalize in vitro IgA production in IgA-deficient (IgAD) patients.

In the present study we evaluated in vitro immunoglobulin production from IgAD individuals and healthy controls. Peripheral blood mononuclear cells (PBMC) from IgAD and controls were cultured with anti-CD40 MoAb presented on a CDw32-transfected fibroblast cell line (CD40 system) in the presence of IL-10, IL-2, IL-4, transforming growth factor-beta (TGF-beta) alone as well as of IL-10 in combination with each of the other three cytokines. Only IL-10 added alone induced significant changes in baseline immunoglobulin production; marked increases in median supernatant levels of all three isotypes were observed in both groups. The most striking finding of this study was the synergizing effect of IL-4 on IgA production in the IgAD group when added with IL-10; median IgA supernatant level increased to a value superimposable on that found in the normal controls which remained about the same as when stimulated with IL-10 alone. The synergic effect of IL-4 and IL-10 was specific to the IgA isotype.

Adolescent↗
PubMed1996

(R,S)-3,4-dichlorobenzoylalanine (FCE 28833A) causes a large and persistent increase in brain kynurenic acid levels in rats.

Kynurenic acid is an endogenous excitatory amino-acid receptor antagonist with neuroprotective and anticonvulsant properties. We demonstrate here that systemic administration of the new and potent kynurenine 3-hydroxylase inhibitor (R,S)-3,4-dichlorobenzoylalanine (FCE 28833A) causes a dose-dependent elevation in endogenous kynurenine and kynurenic acid levels in rat brain tissue. In hippocampal microdialysates, peak increases of 10- and 80-fold above basal kynurenic acid concentrations, respectively, were obtained after a single oral or intraperitoneal administration of 400 mg/kg FCE 28833A. After intraperitoneal treatment with FCE 28833A, extracellular brain kynurenic acid levels remained significantly elevated for at least 22 h, rendering this compound a far more effective enhancer of kynurenic acid levels than the previously described kynurenine 3-hydroxylase blocker m-nitrobenzoylalanine. FCE 28833A and similar molecules may have therapeutic value in diseases which are linked to a hyperfunction of excitatory amino-acid receptors.

Animals↗
PubMed1996

Ontogeny of CD40L [corrected] expression by activated peripheral blood lymphocytes in humans.

The CD40 ligand (CD40L) is a molecule expressed by activated T cells which plays a critical role in the regulation of B-cell responses, including differentiation into Ig-producing cells. Using the specific monoclonal antibody TRAP1 we have evaluated the ontogeny of CD40L expression in 97 normal individuals between birth and 50 years of age. The expression of CD40L is a function of age; it is severely reduced at birth, progressively increases during the first months of life, and reaches a plateau in the second decade. This progressive attainment of the ability to express CD40L is due to a process of maturation of the CD4 + subset, being significantly correlated with the expression of the CD45RO antigen.

Adolescent↗
PubMed1996

Quality assurance of clinical transfusion practice by implementation of the privilege of blood prescription and computerized prospective audit of blood requests.

Guidelines, algorithms and recommendations have been issued in the attempt to ensure appropriateness of transfusion practice, but the results are less than satisfactory, mainly due to the difficulty to turn paper procedures into actual practice. In our hospital we have tried to overcome this difficulty through the implementation of a quality assurance programme which includes giving the privilege of nonurgent blood prescription to a limited number of physicians and a computerized prospective audit of blood requests. The latter is performed through verification of the compliance of blood requests, which are designed to include a patient's laboratory and clinical data, with hospital guidelines for the proper use of blood. In the 12 months since implementation of the computerized prospective audit the transfusion service has evaluated 7884 requests. Of these, 63.4% (n = 4998) were for red blood cells, 21.1% (n = 1664) for platelets and 15.5% (n = 1222) for fresh frozen plasma. The prospective audit showed that 96.8% and 98.1% of requests for red units and platelets were appropriate, respectively. Conversely, approximately 27% of plasma requests did not comply with guidelines, mainly because the evidence of coagulopathy was missing. However, inappropriateness of plasma requests for elective general surgery decreased from 39% at the onset of the programme to 14% in the last trimester considered. Moreover, the evaluation by retrospective audit of the proportion of patients transfused with both red blood cells and plasma in the perioperative period out of those transfused with red blood cells only, as an indicator of unwanted reconstitution of whole blood, showed that this proportion decreased from 47.6% (320/672) in the 12 months before implementation of computerized audit to 37.8% (244/646) in the following 12 months (difference = -9.8%, 95% confidence interval of the difference from -4.5% to -15.1%; P < 0.005 by chi 2 test). Our initial experience, together with the present system, shows that (1) the restriction of nonurgent blood prescription to a group of clinicians more educated in transfusion medicine than average clinicians practicing in a large multispecialty hospital is feasible; (2) prospective audit is a useful tool for assuring the quality of blood requesting.

Algorithms↗
PubMed1996

Italian experience with AutoCapture in conjunction with a membrane lead. Pacesetter Automatic Control of Energy and Membrane Automatic Threshold Evaluation (Pacemate) Study Group.

AutoCapture is a programmable feature of the Pacesetter Microny SR + 2425T VVIR pacemaker, which provides for the automatic capture verification, increase in output in the presence of noncapture and threshold searching, with adjustment of output settings. The effectiveness of this unit in conjunction with the Membrane models 1400T and 1401T bipolar endocardial leads was studied in 54 patients followed at 19 Italian Centers. The patients were randomized at the time of implantation to receive either the model 1400T or the 1401T lead. The electrodes in these leads are covered by a Nafion membrane, which was either impregnated (model 1400T) or not-impregnated (model 1401T) with steroid. This paper reports the data collected over the first six weeks postimplantation. The results of the automatic capture function was compared to the capture threshold measured using the Vario technique at the time of predischarge evaluations, and weeks 1,2, and 6 of postimplant follow-up. The reliability and effectiveness of the pulse generator-lead system allowed for consistent pacing at very low outputs and safety preserved at a programmed output only 0.3 V above the capture threshold.

Aged↗
PubMed1996

[Ischemic cardiopathy in the young: coronarographic and autopsy picture in 100 subjects].

Many aspects of coronary artery disease in young people are not completely understood. Our study concerns a series of 100 patients < 45 years with acute coronary artery disease. Sixty patients survived and 40 died suddenly. All subjects have been divided into four groups: Group I includes 20 deceased patients with anatomic features of acute myocardial infarction. Group II includes 20 subjects dead without features of acute myocardial infarction. Group III includes 30 patients surviving the first acute myocardial infarction. Group IV includes 30 patients surviving unstable angina. The coronary arteries have been studied by anatomic dissection in Group I and II and with coronarography in Groups III and IV. The left main was only involved in Group I and II patients. Multivessel disease was more frequent in Group I and II, but the difference was not significant. These results underline that coronary artery disease with multivessel involvement is not rare in young patients. The rare occurrence of left main disease at coronary angiography could be the consequence of the natural preselection determined by sudden death.

Adult↗