Magnocellular and parvocellular developmental course in infants during the first year of life

The visual system undergoes major modifications during the first year of life. We wanted to examine whether the magnocellular (M) and parvocellular (P) pathways mature at the same rate or if they follow a different developmental course. A previous study carried out in our laboratory had shown that the N1 and P1 components of pattern visual evoked potentials (PVEPs) were preferentially related to the activity of P and M pathways, respectively. In the present study, PVEPs were recorded at Oz in 33 infants aged between 0 and 52 weeks, in response to two spatial frequencies (0.5 and 2.5 c deg(-1)) presented at four contrast levels (4, 12, 28 and 95%). Results indicate that the P1 component appeared before the N1 component in the periods tested and was unambiguously present at birth. The P1 component showed a rapid gain in amplitude in the following months, to reach a ceiling around 4-6 months. Conversely, the N1 component always appeared later and then gained in amplitude until the end of the first year without reaching a plateau. Latencies were also computed but no developmental dissociation was revealed. Results obtained on amplitude are interpreted as demonstrating a developmental dissociation between the underlying M and P pathways, suggesting that the former is functional earlier and matures faster than the latter during the first year of life.     

Therapeutic vaccination for future management of HIV/AIDS

The investigation of novel and innovative treatment approaches for long-term management of HIV-infection has intensified due to the growing number of infected individuals worldwide and the constraints of resistance, toxicity and inconvenience associated with lifelong therapy. Current treatment relies entirely on antiretroviral drugs targeting various stages of the life cycle of HIV, rather than on leveraging the immune system. However, the boosting of HIV-specific immune responses in chronic infection offers a vast potential for synergy with antiretroviral drugs, thereby contributing to durable control of viral replication. A novel immunotherapeutic agent that delivers plasmid DNA to dendritic cells after topical skin application is the first therapeutic vaccine that has demonstrated immunological and clinical benefit in chronically infected rhesus macaques in combination with antiretroviral therapy.     

Risk groups for hepatitis A virus infection

We report the conduct and results of a systematic search for evidence of risk of infection with hepatitis A virus (HAV) among blood transfusion recipients, travellers, the military, healthcare workers, sewage workers, foodhandlers, day care assistants, institutionalised subjects, blood transfusion recipients, drug addicts, homosexuals, prisoners and other risk groups such a liver transplantees. We report our recommendations for the use of the HAV vaccine in these groups.     

Epidemiological profile of cocaine users on treatment in psychiatrics hospitals, Brazil

OBJECTIVE: To describe the epidemiological profile and patterns of cocaine use among hospitalized drug users. METHODS: A cross-sectional study was carried out among drug users, aged 18 years or more, hospitalized in one out six selected psychiatric hospitals in the metropolitan area of Greater S o Paulo, whose clinical conditions allowed them to reliably answer to a standardized questionnaire and who agreed to participate. Six psychiatric hospitals who attended spontaneously referred public and private patients from all Greater S o Paulo were selected. Data collection was conducted using structured interviews, individually applied by a trained psychologist. Statistical analysis was performed using Student t-test and Chi-square test at p<0.05. RESULTS: There was a predominance of crack use (38.4%) over intravenous drug use (1.6%). Addicts who smoked cocaine had lower education, most were unemployed and had previously lived on the streets, and used higher amounts of drugs. These addicts also had been previously incarcerated more often than addicts who used other routes for drug administration. CONCLUSIONS: Drug use is a serious public health problem in Greater S o Paulo, and this is shown by the great amount of hospital admissions due to drug addiction. Crack users have lower socioeconomic status and more often engage in violence and crimes.     

Prevalence of sexual disorders in those young males who later become drug abusers

The purpose of this study was to learn about the frequency of sexual disorders in young males who later become substance abusers. We interviewed 228 men treated in 10 drug centers for substance abuse. The questionnaire that we used was designed to assess the onset of erectile dysfunction (ED) or of premature ejaculation (PE). Only those subjects who became substance users between the ages of 17 to 29 were taken into consideration. Of the 228 subjects recruited, only 130 met the inclusion criteria (mean age 33). These male patients had a prevalence of ED of 20.3% (cl 99% 12.3-31.2), whereas the prevalence of ED of age-matched males in the general population is 2.1% (cl 99% 0.36-5.46; p < 0.000001). The prevalence of PE in the sample prior to drug use was 37.5%. Sexual desire was in the normal range in nearly all subjects. The prevalence of ED in the men of our sample is higher than in age-matched individuals of the general population. These data suggest a new hypothesis: sexual disorders or the conviction that one has a sexual problem is a possible risk factor among men for drug abuse and addiction.     

An inter- and intra-laboratory comparison of breath ¹³CO₂analysis

BACKGROUND: 13C breath test analysis requires accurate 13CO2 measurements. AIM:: To perform a multicentre study to evaluate the repeatability and reproducibility of breath 13CO2 analysis. METHODS: Two series of 25 paired randomly coded tubes (each consisting of 23 13CO2-enriched breath samples and two samples of standard reference pure CO2 with certified delta 13CPDB) were sent to participating centres for 13CO2 measurement. Each series of tubes was analysed 10 days apart. The repeatability and reproducibility of 13C measurements was assessed by Mandel's k and h statistics. RESULTS: Twenty-two centres participated in the study: 18 showed good inter- and intra-laboratory variability, whilst four showed abnormally high inter- or intra-laboratory variability. Breath test results were also significantly affected by the accuracy of the 13C analytical procedures. CONCLUSIONS: A low accuracy of 13C measurements may significantly affect the results of breath tests, leading to inappropriate clinical decisions. Standardization of 13C analysis is required to guarantee optimal 13C measurements and accurate 13C breath test results.