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Biomedical subjects

M Leal

Publications and source records attributed to M Leal.

At least 91 records · Page 5Linked to original sources
PubMed1994

High rate of nonspecific anti-hepatitis C reactivity amongst homosexual men in comparison with that found in other sexually active groups and blood donors. Viral Hepatitis and AIDS Study Group.

OBJECTIVES: To investigate the concordance of anti-hepatitis C virus (anti-HCV) reactivity by a second-generation enzyme immunoassay (EIA-2) and by a four-antigen recombinant immunoblot assay (4-RIBA) in homosexual men, in comparison with that found in other sexually active groups and blood donors. DESIGN: Prospective study. SETTING: Tertiary referral centre, Seville, Spain. SUBJECTS: A total of 1203 subjects were studied. Eight hundred and three were sexually active individuals: 547 female prostitutes, 88 heterosexual men who had frequent sexual intercourse with prostitutes, and 168 homosexual men. All of them denied blood transfusion and parenteral drug use. In addition, 400 voluntary blood donors were selected at random. MAIN OUTCOME MEASURES: All serum samples were screened for anti-HCV by EIA-2 and repeatedly reactive sera were tested by 4-RIBA. Homosexual men were also screened for anti-human immunodeficiency virus (anti-HIV), hepatitis B virus (HBV) markers and gammaglobulin concentration. Finally, serum samples from homosexual men reactive for anti-HCV by EIA-2 were analyzed for HCV-RNA by polymerase chain reaction (PCR). RESULTS: Concordance between EIA-2 and 4-RIBA in female prostitutes (71.4%), clients of prostitutes (75.0%), and blood donors (83.3%) was significantly higher than in homosexual men (38.8%) (P < 0.04). In this collective the concordance between 4-RIBA and PCR was 85.7% for positive cases and 88.8% for negative ones, and EIA-2 ratios in reactive sera were significantly higher in 4-RIBA confirmed cases (P < 0.0001). No correlation between false positive EIA-2 results and presence of HIV infection, HBV markers or hypergammaglobulinaemia was found in homosexual men by univariate analysis. CONCLUSIONS: There is a high level of non-specific anti-HCV reactivity by EIA-2 amongst homosexual men in comparison with that found in other sexually active groups and blood donors. The true prevalence of HCV infection amongst homosexual men could be even lower than previously described.

Adult↗
PubMed1994

Predictive value of IgM antibodies to hepatitis C virus in patients with chronic hepatitis C undergoing interferon-alpha therapy. Analysis by two different methods.

To determine the predictive value of IgM anti-hepatitis C virus (HCV) testing in patients with chronic hepatitis C infections undergoing interferon-alpha (IFN-alpha) therapy, IgM anti-HCV reactivity was analysed by two different methods (non-commercial and commercial) in 19 patients and monitored at times 0 (pretreatment), 3, 6, 12, and 24 months during follow-up. Eight patients were non-responders, five remained in sustained response 1 year after stopping treatment, and six had a relapse. No correlation between alanine transaminase (ALT) levels and IgM anti-HCV reactivity was found by either method in baseline samples. In addition, neither the presence nor absence of IgM anti-HCV in baseline samples, nor the loss of specific IgM reactivity during treatment, had any predictive value. Finally, no other parameters analysed (age, sex, risk group and histological diagnosis), were significantly associated with IgM anti-HCV reactivity in our study. In summary, these results suggest that baseline detection and monitoring of IgM anti-HCV reactivity are not useful in predicting the sustained response to IFN-alpha therapy in chronic hepatitis C infection.

Adult↗
PubMed1994

[Pacemaker implantation in a patient with persistent left superior vena cava and atresia of the right superior vena cava].

Persistent left superior vena cava with absence or atresia of right superior vena cava is a congenital abnormality of systemic venous return to the heart which may complicate the insertion of a pacemaker electrode. We present a case report of a patient with conduction system disturbances in whom this abnormality was diagnosed during pacemaker implantation, with the possibility of using a transvenous electrode without active fixation system.

Aged↗
PubMed1993

[A multicenter study of infection with human immunodeficiency virus type-2 (HIV-2) in Spain (1991). The Spanish Group for the Study of HIV-2].

BACKGROUND: To January 1991 thirteen cases of HIV-2 infection had been reported in Spain. Paradoxically, neighboring countries, i.e. France and Portugal, have reported more than one thousand cases, and are the most HIV-2 prevalent areas outside West Africa. We report the results of a prospective, nationwide study on the prevalence of HIV-2 infection conducted in Spain in 1991. In addition, an evaluation of testing methodologies is made. METHODS: Sera collected from 8,073 individuals at high-risk for HIV infection were screened by a combined HIV-1 plus HIV-2 ELISA. Reactive samples were further evaluated by three tests, as HIV-1 Western blot (WB), HIV-2 specific WB, and a synthetic peptide assay immuno-dot (Pepti-lav, Pasteur). RESULTS: Fifteen (0.18%) individuals met criteria of HIV-2 infection in both specific WB and SPA. Four (27%) of them showed reactivity to both HIV-1 and HIV-2, and the dual infection was confirmed by polymerase chain reaction (PCR) in 2 out of 3 available samples. The SPA showed higher sensitivity and specificity than WB in the diagnosis and distinction of HIV-1 and HIV-2 infections. CONCLUSIONS: To January 1992, 28 cases of HIV-2 infection have been described in Spain. All but two were African immigrants. The first cases of HIV-1 plus HIV-2 coinfection have been identified. In HIV high-risk populations, SPA may provide an excellent alternative to WB to confirm ELISA reactive samples.

Africa↗
PubMed1993

[Prevalence of antibodies against hepatitis C virus in a sample of homosexual males].

BACKGROUND: The finding of an important proportion of cases of hepatitis C without previous contact with blood or hemoderivates has led to suspect that there may be other routes of transmission among which sexual transmission may be found. METHODS: The presence of antibodies against the hepatitis C virus (anti-HCV) and the association of this infection with certain epidemiologic parameters and sexual practice was determined in 184 homosexual males with no other risk factors for virasis of intravenous transmission. Moreover, the prevalence of anti-HCV was evaluated in 210 voluntary blood donors. Every homosexual was surveyed on sexual practice and the first serum sample available of each of these patients was analyzed for anti-HVC and anti-HIV-1. RESULTS: Twenty-two homosexual (12%) were anti-HCV positive while only one (0.5%) of the control was positive for this marker (p < 0.0001). Thirty-six cases (19%) were anti-HIV positive (none of the controls). No statistical association was found between both serologic markers or between the presence of anti-HCV and the epidemiologic parameters evaluated. CONCLUSIONS: Homosexuals constitute a risk group for hepatitis C virus infection although the sexual route is probably not effective for transmission of this entity.

Adult↗
PubMed1993

Hepatitis C virus infection among sexually promiscuous groups and the heterosexual partners of hepatitis C virus infected index cases.

To define the role of sexual transmission in the spread of hepatitis C virus (HCV) infection, a seroprevalence study of antibodies against HCV was performed in populations at high risk for sexually transmitted diseases. Subjects included 310 female prostitutes, 88 clients of prostitutes, 168 homosexual men and 147 stable heterosexual partners of index cases reactive for anti-HCV (98 of whom were partners of drug addicts coinfected with HCV and human immunodeficiency virus [HIV]). All subjects denied prior transfusion or intravenous drug use. Controls were 400 voluntary blood donors selected randomly from first-time donors. The prevalence of anti-HCV by enzyme immunoassay, confirmed by a second-generation recombinant immunoblot assay, was 6.4% in prostitutes, 6.8% in clients of prostitutes, 4.2% in homosexual men, 7.4% in heterosexual partners of index cases and 1.2% in random donors. However, the anti-HCV prevalence in stable heterosexual partners of HCV-positive/HIV-positive index cases was 2.2 times higher than in stable heterosexual partners of index cases reactive for anti-HCV only (9.2% vs. 4.1%), and sexual partners of index cases coinfected with HCV and HIV were almost three times more likely to be infected with HIV than with HCV (25.5% vs. 9.2%). These data suggest that HCV infection may be sexually transmitted but with low efficiency and that this efficiency could be increased in the presence of coexistent HIV infection in the index case.

Adolescent↗
PubMed1993

Failure to detect silent HIV infection by polymerase chain reaction in subjects at risk for heterosexually transmitted HIV type 1 infection.

The prevalence of silent HIV-1 infections in subjects at risk of acquiring HIV infection by heterosexual transmission was assessed using a nested polymerase chain reaction (PCR) assay. The two groups of risk subjects consisted of 92 female prostitutes and 43 heterosexual partners of infected individuals. Appropriate positive and negative control persons were included in the study. Serum samples were also tested for antibody to HIV-1 by an enzyme immunoassay (EIA) and positive results confirmed by Western blot. PCR results in the two risk groups and the positive and negative controls were in full agreement with serological results. It is concluded that silent infection with HIV-1 is infrequent in persons at risk for heterosexual transmission.

Adolescent↗
PubMed1993

Hepatitis B virus occult infection in subjects with persistent isolated anti-HBc reactivity.

The aim of this study was to investigate the presence of hepatitis B virus occult infection in asymptomatic subjects with persistent anti-HBc reactivity but no other hepatitis B virus serological markers, including HBsAg, anti-HBs, IgM anti-HBc and HBV-DNA. For this purpose we used both polymerase chain reaction assays in sera and immunohistochemistry for HBsAg and HBcAg in liver biopsy specimens. Twenty-four cases were studied: 15 were drug abusers or homosexuals (eight with normal alanine aminotransferase levels) and nine were heterosexuals with raised alanine aminotransferase levels (> 45 U/l) but with no history of blood transfusion or ethanol intake (< 80 g daily). In all but five cases, liver biopsy was performed in subjects with persistent elevated alanine aminotransferase levels. In 10 out of 24 cases (41.66%) hepatitis B virus infection was demonstrated by polymerase chain reaction or immunohistochemistry, and when results from both procedures were available (n = 11) hepatitis B virus infection was detected in 63.63% of the subjects. The only clinical feature associated with HBV infection was the presence of persistent elevated alanine aminotransferase levels (p < 0.05). In conclusion, persistent isolated anti-HBc reactivity may be a relatively common serologic pattern for hepatitis B virus occult infection, at least in patients with chronic liver disease.

Base Sequence↗
PubMed1992

[Multicenter study of the prevalence of type 2 human immunodeficiency virus infection in Spain (1990)].

BACKGROUND: HIV-2 is a new retrovirus which may produce AIDS and has been mainly described in individuals from West Africa. More than 400 cases have been reported in France and Portugal while in Spain very few cases of HIV-2 infection have been reported with few studies having been made concerning the prevalence of the disease. This multicentric study analyzes the prevalence of HIV-2 infection in subjects of different risk groups in Spain and evaluates the diagnostic efficacy of different methodologies. METHODS: The presence of HIV-2 antibodies was analyzed in 902 serum samples of high risk individuals collected in 1990 from: 386 drug addicts, 246 not drug addict prostitutes, 184 West Africans and 86 homo/bisexual individuals. These samples were from Barcelona, Sevilla, and Malaga. The detection of antibodies was carried out by enzymatic immunoanalysis (EIA), Western blot (WB) and an enzymoimmuno-dot (EID) designed with synthetic peptides. RESULTS: Positive serology only for HIV-2 was detected in 7 samples from African immigrants. Two drug addicts presented double reactivity HIV-1/HIV-2 in all the tests suggesting double infection. No prostitutes or homo/bisexual males were identified with positive serology for HIV-2. Cross-reactivity between HIV-1 and HIV-2 was more frequently detected in WB than in EID. Greater discordance was found in the results obtained by EIA, WB, and EID in the West Africans than in the analysis of the samples of native subjects. CONCLUSIONS: This study demonstrates that, for the time being, HIV-2 infection in Spain is rare although from among immigrants from endemic areas subjects with behavior to risk of transmission to the autochthonous population have been identified. The use of techniques designed with synthetic peptides may be of use to discriminate HIV-1 and HIV-2 infection in positive samples by enzymatic immunoanalysis (EIA) and Western blot which use a viral lysate as antigenic material.

Acquired Immunodeficiency Syndrome↗
PubMed1992

The metabolism of CGS 15873 in man using stable isotope pattern recognition techniques.

CGS 15873 is a relatively specific dopamine agonist with preferential activity at the presynaptic autoreceptor and therefore may represent a novel agent for the treatment of schizophrenia and/or Parkinson's disease. Several metabolites have been identified in the rat and monkey using an isotopically enriched dosing solution and pattern recognition techniques coupled with GC/MS and LC/MS. In this study, the metabolism of CGS 15873 was investigated in man using these same techniques. In urine, specific isotope clusters were found that matched the dosing solution pattern. Three metabolites were identified: an O-glucuronide conjugate of the parent drug, N-despropyl CGS 15873, and a keto metabolite of CGS 15873. Thermospray LC/MS allowed for the direct confirmation of the conjugated metabolite. GC/MS required derivatization but afforded greater sensitivity compared to LC/MS.

Adult↗
PubMed1992

Variational analysis of the transdermal delivery rate from two prototypical ethanol-water nitroglycerin TTS devices and Transderm-Nitro 10 in the normal population.

The performance of two prototypical ethanol-water flux-enhanced transdermal therapeutic systems were compared to the performance of commercial Transderm-Nitro 10. This was a single-center, open-label, three-treatment, randomized crossover study in six healthy subjects who completed the study. Concurrent with each transdermal treatment, an infusion of the stable isotope [15N]3-nitroglycerin was administered. The use of double isotope methodology was incorporated into this study to minimize the variation introduced by fixed-effect error on the evaluation of transdermal flux. The objectives of this study were to isolate experimentally and characterize the average flux enhancement of each prototype, to determine the temporal profile of delivery, and to evaluate the components of variance of drug delivery from each transdermal system. The results of this study showed that the two flux-enhanced transdermal systems with different fill volumes both produced flux enhancement factors of 2 to 3 relative to Transderm-Nitro 10. Prototype B demonstrated a 57% reduction in intersubject variation relative to Transderm-Nitro 10 indicative of enhanced control of drug permeation across a subject population. Prototype A, while reducing intersubject variations, was less than optimal. Both prototypes demonstrated comparable intrasubject variation relative to Transderm-Nitro 10, indicating similar stability for within-subject transdermal drug delivery. The flux enhancement and variational properties of Prototype B were consistent with those intended based on mechanistic considerations of mutual nitroglycerin and ethanol-coupled transdermal delivery.

Administration, Cutaneous↗