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C Malavé

Publications and source records attributed to C Malavé.

10 recordsLinked to original sources
PubMed2004

A real-time quantitative PCR comparative study between rat optic and sciatic nerves: determination of neuregulin-1 mRNA levels.

Injured axons from peripheral nervous system (PNS) possess the ability to regenerate. In contrast, regeneration of injured axons does not occur in the central nervous system (CNS) or occurs to a limited extent. Previous works have shown that rat sciatic nerve conditioned medium (CM) produced PC12 cells neuronal-like differentiation and neurite outgrowth. In the present work, we compared the expression of neuregulin-1s (NRG-1s) from rat sciatic and optic nerves as members of the PNS and CNS, respectively. Sciatic nerve CM showed a higher neurotrophic activity on PC12 cells than rat optic nerve CM. RT-PCR analysis verified the presence of all three types of NRG-1 mRNAs and their receptors in both types of nerves. Real-time quantitative PCR (QPCR) assays showed that the relative expression levels of all three types of NRG-1 mRNAs were higher in optic nerves than in sciatic nerves. Eleven-day cultured optic nerves showed an increased in NDF and SMDF when compared to freshly isolated optic nerves, whereas GGF decreased. However, 11-day-cultured sciatic nerves only showed an increase in SMDF mRNA. Western blots corroborated the differences in NRG-1 expression profile for both types of nerves and their CMs. Incubation of both CMs with the anti-pan-NRG-1 antibody showed that the neurotrophic activity of the optic nerve CM increased, whereas the sciatic nerve CM remained unchanged. These results indicated that different NRG-1 levels are expressed upon nerve degeneration and the balance between those levels and other neurotrophic factors could have an important role on nerve regeneration.

Animals↗
PubMed1995

Association between HIV and other DNA viruses in vitro.

To investigate the association of human immunodeficiency virus (HIV) with various DNA viruses, including hepatitis B virus (HBV), cytomegalovirus (CMV) and Epstein-Barr virus, (EBV), simultaneous detection of HIV p24 antigen, HBV surface antigen and DNA, CMV-DNA and EBV-DNA expression was performed in phytohemagglutinin-stimulated peripheral blood mononuclear (PBMC) culture supernatants obtained from 54 individuals at risk for HIV infection. HIV expression in PBMC culture supernatants never occurred alone; expression of other viruses was always detected in the 24 samples expressing HIV antigen in vitro. Furthermore, in 16 patients expression of other viruses was detected without HIV expression, and in 14 patients none of the tested viruses were detected. These results indicate a strong association between the presence of HIV antibody and expression of DNA viruses in vitro (p = 0.0001). The coexpression of these viruses could be related to the evolution of HIV infection and AIDS.

Cells, Cultured↗
PubMed1991

[Detection of hepatitis B virus DNA in peripheral blood mononuclear cells from patients with various hepatopathies using in situ hybridization].

We have investigated, by "in situ" hibridisation, the presence of hepatitis B virus (HBV) DNA in peripheral blood mononuclear cells (PBMC) from 45 patients with acute and chronic hepatic disorders directly related with HBV or with some seric HBV marker. Results has been related with serological markers and the different types of hepatopaties. The HBV-DNA was detected in PBMC more frequently in patients with hepatic alterations more prolongated (chronic active hepatitis, chronic persistent hepatitis and cirrhosis) than in acute hepatitis patients. It was not detected in any asymptomatic patient with HBV serological markers. As regards HBV serological markers, HBV-DNA was detected in PBMC in 8/11 HBsAg positive patients and in 11/34 HBsAg negative patients: 3 antiHBc positive, 5 antiHBc and antiHBs positive and 3 without conventional seric markers. The detection of HBV-DNA in antiHBc and/or antiHBs positive subjects means the virus may persist after recovery of infection and suggests PMBC could serve as additional reservoirs for reinfection of hepatocytes leading to a reactivation of the liver disease. Our results suggest that HBV infection of PBMC is a frequent event during HBV infection and can have important consequences fundamentally with respect to pathogenic mechanisms of HBV induced liver disease and to the transmission of the virus.

Acute Disease↗
PubMed1990

[Detection of human immunodeficiency virus in seronegative adults].

The diagnosis of human immunodeficiency virus infection is sometimes difficult or nonspecific, both in early and late stages, as the patients may be seronegative at the time of testing. Although serologic testing usually suffices to identify infected individuals and to follow up the course of the infection, in some cases direct detection of the virus is required. The culture of the mononuclear cells of the patient permits, after stimulation with mitogens and interleukin-2, the expression of viral antigens even in asymptomatic patients with latent or apparently nonproductive infection. In this way we have recovered the virus in four patients without serological evidence of infection. The possibility that human immunodeficiency virus infection can be undetectable with the usual diagnostic techniques, at least in a small proportion of patients, supports the need to use other methods such as direct viral culture to permit the identification of a greater number of infected individuals and the adoption of the appropriate prophylactic or therapeutic measures.

AIDS Serodiagnosis↗
PubMed1990

[Presence of HBsAg in lymphocyte cultured from patients infected with human immunodeficiency virus (HIV)].

The behavior of the hepatitis B virus was investigated in mononuclear cell cultures in nine patients infected by the human immunodeficiency virus. Although only one of them was a carrier of HBsAg and four had anti-HBs in their sera, HBsAg was detected in the supernatant of the cultures from all patients. These results suggest that mononuclear cells might act as a reservoir for hepatitis B virus, and that the concomitant infection by this virus and human immunodeficiency virus may alter the natural evolution of any of both conditions.

Adult↗
PubMed1990

[Detection and antigenic distribution of hepatitis B virus in liver tissue and its relation to other serological markers of viral replication].

The aim of this work has been the production of specific monoclonal antibodies against HBV-antigens and their utilisation in order to study their distribution on liver tissue. The monoclonal antibodies anti-HBc and anti-HBs were obtained by the modified hybridoma technique. This study was performed on 50 patients affected by several chronic hepatopathies. For the detection of the antigens, avidin-biotin-peroxidase complex immunostaining was used. Both cytoplasmic and membranous HBsAg were detected in 15 out of 16 HBsAg+ patients; 8 of 12 HBsAg-/anti-HBc+ patients and 1 HBsAg-/antiHBc- patient. Cytoplasmic and nuclear HBcAg was observed in 12 of 16 HBsAg+ patients and 4 of 20 HBsAg- patients. Although the presence of serum HBsAg is an index of liver infection, in some HBsAg-/antiHB+ patients (20%) with undetectable levels of HBsAg, hepatic injury may be disclosed by the detection of other markers of active viral replication.

Adolescent↗
PubMed1986

In situ detection of amastigotes in American cutaneous leishmaniasis, using monoclonal antibodies.

Using an immunoperoxidase technique we have applied monoclonal antibodies against American Leishmania for the detection of amastigotes in biopsies from cutaneous leishmaniasis patients. The immunocytochemical procedure was notably superior to conventional histological staining in terms of the visualization and definition of the amastigotes. This technique could eventually prove to be of value in epidemiological studies, and possibly have prognostic importance, by allowing the in situ characterization of the species of infecting organism.

Antibodies, Monoclonal↗
PubMed1986

IgE antibody against surface antigens of Leishmania promastigotes in American cutaneous leishmaniasis.

As IgE-mediated immune mechanisms participate in the host defence against some types of parasites, we evaluated sera from American cutaneous leishmaniasis (ACL) patients for the presence of this antibody against Leishmania. Using monoclonal antibodies against human IgE and an immunoperoxidase staining technique, 48% of the patients sera tested were found to contain IgE antibody that bound strongly to Leishmania promastigotes. A much lower proportion of sera from non-symptomatic subjects from either endemic or non-endemic areas of the disease contained significant levels of anti-Leishmania IgE antibody (6.5% and 0% respectively). The results indicated that the IgE antibody bound predominantly to surface components of the promastigotes, and reactivity against the intracellular amastigote form of the parasite was rarely detected. Somewhat unexpectedly, in a small proportion of the sera, the IgE antibody showed apparent specificity for L. mexicana or L. braziliensis. This study demonstrates that ACL patients can develop anti-Leishmania IgE antibody responses, that seem to be directed preferentially against surface antigens of promastigotes, and that can be strain specific. This raises the question as to the possible contribution of this antibody to the immune defence mechanisms against the parasite.

Animals↗
PubMed1984

Incidence of atopic disease in a tropical environment: partial independence from intestinal helminthiasis.

The reported incidence of atopic disease in the tropical environment, albeit somewhat controversial, has often been very low. This has been postulated to be due to an inhibitory influence of intestinal helminthiasis, although the predominantly rural nature of the populations studied might also be an important factor to consider. We evaluated two tropical groups in Venezuela that were basically comparable, both being highly parasitized but one of which was urban and the other rural. The apparent incidence of allergic conditions in the urban group was, in fact, comparable to that in temperate countries, whereas that of the rural subjects was markedly lower. A similar difference was found in skin test positivity to common inhalant allergens, although reactivity to Ascaris extract was comparably high between the two groups, and total serum IgE and eosinophil levels were uniformly elevated. Our results suggest that the incidence of atopic disease in the topical environment may depend not only on the intensity of helminthiasis suffered but also on factors related to the urban-rural situation.

Adolescent↗