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Biomedical subjects

L Pagani

Publications and source records attributed to L Pagani.

At least 19 recordsLinked to original sources
PubMed2006

Deuterium enhancement in H3+ in pre-stellar cores.

Deuterium enhancement of monodeuterated species has been recognized for more than 30 years as a result of chemical fractionation that results from the difference in zero-point energies of deuterated and hydrogenated molecules. The key reaction is the deuteron exchange in the reaction between HD, the reservoir of deuterium in dark interstellar clouds, and the H3+ molecular ion, leading to the production of H2D+ molecule, and the low temperature in dark interstellar clouds favours this production. Furthermore, the presence of multiply deuterated species have incited our group to proceed further and consider the subsequent reaction of H2D+ with HD, leading to D2H+, which can further react with HD to produce D3+. In pre-stellar cores, where CO was found to be depleted, this production should be increased as CO would normally destroy H3+. The first model including D2H+ and D3+ predicted that these molecules should be as abundant as H2D+. The first detection of the D2H+ was made possible by the recent laboratory measurement for the frequency of the fundamental line of para-D2H+. Here, we present observations of H2D+ and D2H+ towards a sample of dark clouds and pre-stellar cores and show how the distribution of ortho-H2D+ (1(1,0)-1(1,1)) can trace the deuterium factory in pre-stellar cores. We also present how future instrumentation will improve our knowledge concerning the deuterium enhancement of H3+.

Journal Article↗
PubMed2003

Clinical stability in human immunodeficiency virus-infected patients with community-acquired pneumonia.

Clinical stability (CS), defined as normalization of vital signs, is often used to manage inpatients with community-acquired pneumonia (CAP). The main objective of our study was to identify a reliable definition of CS for human immunodeficiency virus (HIV)-positive patients with CAP. During an 18-month period, 437 HIV-positive Italian inpatients with CAP were enrolled in the study. We used 3 definitions of CS (from a less conservative [definition 1] to a more conservative [definition 3] definition) based on combinations of different thresholds for vital signs. Assessments were performed at admission and daily during the hospital stay. For the 3 definitions, 14.9%, 8.0%, and 4.8% of patients were stable at baseline, with deterioration after reaching CS in 7.16%, 4.76%, and 2.05%, respectively. The 8 patients whose conditions deteriorated after reaching CS definition 3 (systolic blood pressure, >90 mm Hg; pulse, <90 beats/min; respiratory rate, <20 breaths/min; oxygen saturation, >90%; temperature, <37 degrees C; ability to eat; and normal mental status) survived and were discharged from the hospital. The more conservative definition of CS appears to be reliable for the management of HIV-infected patients with CAP.

Adult↗
PubMed2003

Antibiotic lock-technique for the treatment of catheter-related bloodstream infections.

The management of central venous catheter-related bloodstream infections (CRBSI), though still debated, requires the removal of the line in most cases: we investigated the efficacy of an alternative approach, based on higher concentrations of antibiotics locked within the catheter lumen, in an open, pilot study aimed at preserving the line in place and at eradicating the infection. Thirty consecutive patients carrying a central line over 10 days and who fulfilled criteria for ascertained diagnosis of bacterial CRBSI, had the catheter "locked" with antimicrobials therein; all patients also received systemic antibiotic therapy within the first 48 hours. Subsequently, 15 patients underwent locks alone, and 15 locks plus systemic therapy. Twenty-eight out of 30 (93.3%) patients retained the catheter in place, appearing to be cleared of infection and no treatment-related untoward events were observed. Locks should be considered as effective as line removal in the management of bacterial CRBSI in unselected patients, and could thus provide advantages in terms of resource sparing and lowered antibiotic pressure in the hospital setting.

Adult↗
PubMed2003

Nosocomial infections in HIV-positive patients: an overview.

Nosocomial infections (NIs) constitute a significant public health problem and contribute to prolonged hospitalization, additional healthcare costs and excess morbidity and mortality. NIs appear to be more common in patients with acquired immunodeficiency syndrome (AIDS) as a result of some degree of immunosuppression, prior antiobiotics treatment and greater exposure to invasive devices such as indwelling intravenous catheters. The objective of this article is to give an insight into the main NIs occurring in HIV-infected patients. Literature pertaining to NIs in HIV-infected patients was reviewed. According to the leading studies in the literature, the incidence of NI ranges from 7.9 to 15 per 100 admissions. Bloodstream infections are the most frequent infections, mainly due to intravascular catheters, followed by urinary and respiratory tract infections. Colonization seems to have an important role in the development of NIs among this immunocompromised population. CLinicians need to be aware of the risk of NIs in HIV-infected patients, and must always take these infections into account in their overall management.

Bacteremia↗
PubMed2002

Sequential regimen for early post-surgical infective endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA), unresponsive to standard antibiotic therapy: a case report.

We describe a patient with early post-surgical infective endocarditis due to methicillin-resistant Staphylococcus aureus, who was unsuitable for surgical reintervention and who failed standard antistaphylococcal therapy, but was successfully cured with a sequential regimen including quinupristin/dalfopristin and linezolid.

Acetamides↗
PubMed2001

Effects of grade retention on academic performance and behavioral development.

This study examined the controversial practice of grade retention and children's academic and behavioral adjustment using data from the Quebec Longitudinal Study of Kindergarten Children. We employed an autoregressive modeling technique to detect the impact of being held back during primary school on subsequent academic performance and behavioral development until age 12 years. The results indicate both a short- and long-term negative influence on academic performance for boys and girls. Children's anxious, inattentive, and disruptive behaviors persisted and, in some cases, worsened after grade retention. These prospective associations were long lasting and more pronounced when grade retention occurred early in primary school. Boys were more vulnerable to the negative influence of grade retention on academic performance and classroom disruptiveness. Disruptive behavior in girls was comparatively less associated with long-term consequences than boys. Nevertheless, girls experienced both short- and long-term academic performance problems in the aftermath of grade retention. Children's prosocial behavior appeared unaffected by grade retention. These results are independent of what would have been expected by the natural course of academic and behavioral development.

Achievement↗
PubMed2001

Prevalence of psychiatric diagnoses and the role of perceived impairment: findings from an adolescent community sample.

The present study examined psychiatric functioning in a community sample of adolescents aged 14 to 17 years (average age of 15 years). We administered the Diagnostic Interview Schedule for Children-2.25 (DISC-2.25) to 1,201 adolescents and their mothers to obtain prevalence estimates of DSM-III-R disorders and the amount of perceived impairment associated with these disorders. While adolescent females reported a significantly higher prevalence of psychiatric disorders than males (15.5% vs. 8.5%), mothers indicated no sex difference. Compared with adolescent males, females had significantly higher rates of internalizing, anxiety. and depressive disorders. In contrast, the prevalence of externalizing disorders was significantly higher among adolescent males. The inclusion of an impairment criterion had a significant impact in reducing the prevalence rates of overall psychiatric disorders. This reduction occurred mainly through impairment's effects on internalizing disorders, specifically anxiety-based disorders (i.e., simple and social phobia). Given the limited research on the effect of impairment on the prevalence of adolescent psychiatric disorders, future work in this area seems warranted.

Adolescent↗
PubMed2000

Extended-spectrum TEM- and SHV-type beta-lactamase-producing Klebsiella pneumoniae strains causing outbreaks in intensive care units in Italy.

The aim of the present study was to investigate the production of extended-spectrum beta-lactamases (ESbetaLs) and the epidemiological correlations in a total of 107 Klebsiella pneumoniae strains resistant to third- and fourth-generation cephalosporins. The strains were collected from patients in four intensive care units (3 neonatal and 1 general) in three hospitals in Italy between March 1996 and July 1997. All strains were found to produce ESbetaLs. Phenotypic (antibiotyping and ESbetaL patterns) and genotypic (plasmid profile and pulsed-field gel electrophoresis) analyses showed that a single strain had been responsible for each outbreak in each of the four intensive care units. Isoelectric focusing, activity on substrates and gene sequencing showed that the strains produced SHV-5, SHV-2a, SHV-12 and TEM-52 beta-lactamases. This is not only the first time that ESbetaL-producing Klebsiella pneumoniae strains have been reported as causing epidemics in Italian hospitals, it is also, to the best of our knowledge, the first time that an outbreak caused by a TEM-52 ESbetaL-producing Klebsiella pneumoniae strain has been reported. The data presented here illustrate the complexity of determining the epidemiological pattern of ESbetaL producers in large hospitals that do not have an ESbetaL-monitoring program.

Anti-Bacterial Agents↗
PubMed2000

Molecular profile of Epstein-Barr virus infection in HHV-8-positive primary effusion lymphoma.

Primary effusion lymphoma (PEL) selectively involves the serous body cavities, occurs predominantly in immunodeficient patients and is infected consistently by human herpesvirus type-8. PEL is also frequently infected by Epstein-Barr virus (EBV). The precise pathogenetic role of EBV coinfection in PEL is not fully understood. The lymphoma fails to express the EBV transforming proteins EBNA-2 and LMP-1, whereas it expresses EBNA-1 (latency I phenotype). Some studies have hypothesized that other EBV-positive lymphomas expressing the latency I phenotype may associate with specific molecular variants of EBNA-1, although this issue has not been addressed in PEL. On this basis, this study is aimed at a detailed molecular characterization of EBV in PEL. Fifteen EBV positive PEL (12 AIDS-related, one post-transplant, two arising in immunocompetent hosts) were subjected to molecular characterization of the viral genes EBNA-1 and LMP-1, as well as definition of EBV type-1/type-2. The EBNA-1 gene displayed a high degree of heterogeneity in different cases of PEL, with seven distinct recognizable variants and subvariants. A wild-type LMP-1 gene was detected in 10/15 cases, whereas in 5/15 cases the LMP-1 gene harbored a deletion spanning codons 346-355. EBV type-1 occurred in 11/15 PEL whereas EBV type-2 occurred in 4/15 cases. Despite a high degree of genetic variability of the virus in different PEL cases, each single PEL harbored only one EBV variant, consistent with monoclonality of infection and suggesting that infection preceded clonal expansion. Overall, our results indicate that: (1) individual PEL cases consistently harbor a single EBV strain; (2) EBNA-1 displays a high degree of heterogeneity in different PEL cases; (3) no specific EBV genotype preferentially associates with PEL.

DNA, Viral↗
PubMed2000

Ivermectin alone or in combination with benzyl benzoate in the treatment of human immunodeficiency virus-associated scabies.

In order to establish a safe and reliable treatment for human immunodeficiency virus (HIV)-associated scabies, we have treated 60 episodes of scabies in this setting, occurring in 39 patients, with one of the following regimens: (i) topical treatment with benzyl benzoate solution; (ii) single-dose oral treatment with ivermectin alone; and (iii) combination therapy with benzyl benzoate solution and oral ivermectin, employing the same regimens as single-agent therapy. Patients were stratified according to the severity score of the disease and the outcome (eradication, relapse, failure). We found that both benzyl benzoate and ivermectin alone were quite effective in mild to moderate scabies, but they were both associated with an unacceptable rate of relapse and failure in severe or crusted scabies. In contrast, combined treatment produced an optimal rate of success, without significant treatment-related side-effects. Therefore, we consider that combination treatment with benzyl benzoate solution and oral ivermectin is preferable to single-agent therapy in crusted scabies occurring in HIV/acquired immune deficiency syndrome patients.

AIDS-Related Opportunistic Infections↗
PubMed1999

Disruptive behavior, peer association, and conduct disorder: testing the developmental links through early intervention.

We tested three competing models regarding the role of deviant friends in the trajectory linking early disruptiveness with later conduct problems through the use of a preventive intervention program. The program was implemented during the second and third grade. One model predicted that the program would positively affect later conduct problems by facilitating nondeviant peer association during early adolescence. The second model predicted a direct impact of the program on later conduct problems through the reduction of early disruptiveness. The third model predicted an interaction between postintervention disruptiveness and association with less deviant friends. The results showed that the program's effects on later conduct problems were mediated by the reduction in disruptiveness and by the association with less deviant friends. However, the positive effect of associating with less deviant friends depended on whether children's disruptiveness had been reduced or not by their participation in the program, thus supporting the third model. We recommend using intervention studies to test developmental models.

Attention Deficit and Disruptive Behavior Disorder↗
PubMed1999

Effects of poverty on academic failure and delinquency in boys: a change and process model approach.

Using data from the Montreal Longitudinal-Experimental Study, we examined the impact of poverty (and its correlate, family configuration status) on academic placement and self-reported delinquency in boys at age 16. We then investigated whether the relation between family economic hardship and antisocial behaviour is direct or indirect by considering the value of parenting practices and academic failure as process variables in the model. Data included official records, and parent, teacher, and self-reports. The temporal intensity of poverty was classified into five categories: never-poor; always-poor; poor-earlier; poor-later; and transitory-poverty. Family configuration status was classified by both temporal characteristics and number of marital transitions: intact-family; short-term-single; long-term-single; short-term-remarried; long-term-remarried; and multiple-marital-transitions. Results revealed that when maternal education and early childhood behaviour were controlled, poverty had an effect on both academic failure and extreme delinquency. This effect was independent of family configuration status. Although they both significantly predicted extreme delinquency on their own, academic failure and parental supervision did not mediate the relationship between poverty and delinquency. Divorce increased the risk of theft and fighting at age 16, regardless of financial hardship. Parental supervision only helped explain the effects of divorce on boys' fighting.

Adolescent↗
PubMed1998

Repeated epidemics caused by extended-spectrum beta-lactamase-producing Serratia marcescens strains.

An outbreak of Serratia marcescens involving 42 patients admitted to the general intensive care unit of the Hospital of Varese, Italy, occurred from March 1994 to August 1995. The causative strains were resistant to oxyimino-cephalosporins and monobactams due to their production of an extended-spectrum beta-lactamase. Another outbreak caused by Serratia marcescens strains had occurred in the same unit a few months earlier, from February to October 1993, with the strains involved producing a novel TEM-derived extended-spectrum beta-lactamase. In order to verify whether there were any relationships between isolates from the two epidemics, the strains and their enzymes were characterized. Biochemical data and gene amplification experiments showed that the isolates of the second outbreak harbored a non-conjugative plasmid of approximately 48 kb, codifying for the production of an SHV-derived extended-spectrum beta-lactamase with pI 8.2. Restriction fragment length polymorphism analysis of total genomic DNA by pulsed-field gel electrophoresis of Serratia marcescens isolates unambiguously identified two different bacterial clones responsible for the two epidemics. Epidemiological and microbiological investigations demonstrated the long persistence of Serratia marcescens strains and their circulation in other hospital wards, thus suggesting their possible role as a long-term reservoir for further epidemic spread.

Cross Infection↗
PubMed1998

The impact of family transition on the development of delinquency in adolescent boys: a 9-year longitudinal study.

The purpose of this study was to examine prospectively the impact of family transition on deviant development in a sample of 427 French-Canadian boys participating in a longitudinal study from kindergarten onwards. During the course of the study some boys experienced family transition. We grouped the boys by developmental period and number of marital transitions they experienced: divorced between ages 6 and 11; divorced between ages 12 to 15; remarried between ages 6 and 11; and remarried between ages 12 and 15. From ages 11 to 15 we assessed boys' delinquency and their family processes (parental supervision, punishment, and communication) annually. The results suggest that boys who experienced remarriage between ages 12 and 15 are at greater risk for delinquency. In particular, they showed evidence of comparatively more theft and fighting at earlier ages than their peers from families that had remained intact. At similar points in development, they perceived less expressive parent-child relationships. Finally, these boys also perceived less monitoring by their parents, both overall and at different points in adolescence.

Adolescent↗