High prevalence of HIV infection among homeless and street-involved Aboriginal youth in a Canadian setting

Aboriginal people experience a disproportionate burden of HIV infection among the adult population in Canada; however, less is known regarding the prevalence and characteristics of HIV positivity among drug-using and street-involved Aboriginal youth. We examined HIV seroprevalence and risk factors among a cohort of 529 street-involved youth in Vancouver, Canada. At baseline, 15 (2.8%) were HIV positive, of whom 7 (46.7%) were Aboriginal. Aboriginal ethnicity was a significant correlate of HIV infection (odds ratio = 2.87, 95%CI: 1.02 – 8.09). Of the HIV positive participants, 2 (28.6%) Aboriginals and 6 (75.0%) non-Aboriginals reported injection drug use; furthermore, hepatitis C co-infection was significantly less common among Aboriginal participants (p = 0.041). These findings suggest that factors other than injection drug use may promote HIV transmission among street-involved Aboriginal youth, and provide further evidence that culturally appropriate and evidence-based interventions for HIV prevention among Aboriginal young people are urgently required.     

Evidence for endogenous formation of tobacco-specific nitrosamines in rats treated with tobacco alkaloids and sodium nitrite

Carcinogenic tobacco-specific nitrosamines are present in tobacco products and are believed to play a significant role in human cancers associated with tobacco use. Additional amounts of tobacco-specific nitrosamines could be formed endogenously. We tested this hypothesis by treating rats with nicotine and sodium nitrite and analyzing their urine. Initially, we treated groups of rats with (S)-nicotine (60 micromol/kg) and NaNO2 (180 micromol/kg), (S)-nicotine alone, NaNO2 alone or 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK, 12 nmol/kg) by gavage twice daily for 4 days. We collected urine and analyzed for two metabolites of NNK; 4-(methylnitrosamino)-1-(3- pyridyl)-1-butanol and its glucuronide. We did not detect these metabolites in the urine of rats treated with nicotine alone or nicotine plus NaNO2, indicating that endogenous conversion of nicotine to NNK did not occur. However, the urine did contain N'- nitrosonornicotine (NNN), N'-nitrosoanabasine (NAB) and N'- nitrosoanatabine (NAT). Analysis of the (S)-nicotine used in this experiment demonstrated that it contained trace amounts of nornicotine, anabasine and anatabine. In a second experiment, we used an identical protocol to compare the endogenous nitrosation of this (S)-nicotine with that of synthetic (R,S)-nicotine, which did not contain detectable amounts of nornicotine, anabasine or anatabine. NNN (0.53 x 10(-3)% of nicotine dose), NAB (0.68%) and NAT (2.1%) were detected in the urine of the rats treated with the (S)-nicotine and NaNO2. NNN (0.47 x 10(- 3)% of dose), but not NAB or NAT, was present in the urine of the rats treated with synthetic (R,S)-nicotine and NaNO2. NNN probably formed via nitrosation of metabolically formed nornicotine. These results demonstrate for the first time that endogenous formation of tobacco- specific nitrosamines occurs in rats treated with tobacco alkaloids and NaNO2. The potential significance of the results with respect to nitrosamine formation in people who use tobacco products or nicotine replacement therapy is discussed.      

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Multiple sclerosis: a clinico-biological study of 100 cases in Spain.

A study was carried out on 100 cases with the clinical diagnosis of multiple sclerosis. Several clinical and analytical factors were considered and correlated. Special attention was paid to data obtained from cerebrospinal fluid (CSF) electrophoresis. The degree of severity of the disease does not affect the selective evaluation frequency of gamma-globulin or its average values. A greater frequency of definite gamma-globulin increase is observed in patients with a stationary development than in those a progressive development although, in both instances, the average values of gamma-globulin do not show any significant difference. There is no correlation between the CSF data and the presumed clinical site of the lesion. Those patients with a single lesion have a lower incidence of pathological data in CSF than those with multiple lesions. A higher proportion of pathological results is seen in CSF of patients with a chronic evolution from the onset than in chronic-intermittent cases. The cases studied during a relapse show a marked decrease in the frequency of definite gamma-globulin increase and paretic colloidal curves. This group of patients gives lower average values of gamma-globulin, total protein and cells, than those patients examined out of relapse. These results are in agreement with recent immunopathological observations.     

Prekallikrein-Kallikrein conversion rate as a predictor of contrast material catastrophies

An in vitro is described that attempts to detect patients with a potential for adverse systemic reactions to contrast material. This test involves measuring the rate of conversion of prekallikrein to kallikrein under certain standard conditions. In a preliminary retrospective study, the test could be used to identify such patients with a sensitivity of 88%, a specificity of 82%, and a predictive value of 79%.     

Upper urinary tract tumor: differential diagnosis by radiological images

To perform the adequate treatment of upper urinary tract lesions it is very important to have an exact diagnosis. When the suspicion of an upper tract urothelial tumor is established the initial evaluation is carried out by imaging diagnostic tests (intravenous urography, pyelography, and others). The association of radiological tests and urine cytologies allows us to get to a correct diagnosis in most cases. Upper urinary tract endoscopy solves some equivocal cases, but sometimes it is impossible to clarify the nature of the lesion in spite of a comprehensive diagnostic effort. Therapeutic decision should be individualized in these cases. The objective of this article is to describe the various features of upper tract urothelial tumors in a variety of available imaging tests, and to review all conditions that may have similar images, describing the characteristic radiological findings for each of them. We discuss about differential diagnosis and perform a critical evaluation of the diagnostic difficulties that occasionally present upper urinary tract diseases.