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Biomedical subjects

M C Maroto

Publications and source records attributed to M C Maroto.

At least 37 records · Page 2Linked to original sources
PubMed1998

GBV-C RNA presence in several high-risk groups of Spain.

GB virus C subtype (GBV-C) seems to share the same routes of transmission as other parenteral transmitted viruses. We have evaluated the prevalence of GBV-C in 247 patients with potential risk for GBV-C infection and in 91 healthy blood donors. The presence of GBV-C RNA was examined by polymerase chain reaction in serum samples. The 23.6% of parenteral drug users were GBV-C positive, 36.3% of them were also HIV infected. Moreover, 22.5 and 19% of sera from patients with HBV and HCV chronic hepatitis, respectively, but without apparent risk factors seemed GBV-C infected. Finally, the 6% of patients on hemodialysis were also positive. Therefore, these results suggest that GBV-C is transmitted by parenteral routes but other non-parenteral routes shared with HBV or HCV must be considered.

Adult↗
PubMed1998

A recombinant protein-based enzyme immunoassay for IgM antibody to human cytomegalovirus.

The reliability of an enzyme-linked immunosorbent assay (ELISA) which used recombinant antigen to detect human cytomegalovirus IgM was studied. Serum samples from each of 283 children aged 5 +/- 2 years were studied. In all samples the anti-IgM antibodies were investigated with the ELISA techniques Enzygnost (Behring) and ETI-Cito (Sorin) which were both based on whole viral particles, and OPUS (Behring) based on recombinant antigen. Of the samples, 254 (89.4%) were negative with all three tests. The 29 remaining samples were positive with one or two of the three techniques. The diagnostic efficacy of Enzygnost, ETI-Cito and OPUS, respectively, was for sensitivity of 50%, 66.7% and 50%, and for specificity of 100%, 95.6% and 96%, respectively. The results with each of the three ELISAs did not differ widely and their diagnostic efficacy was similar. The method based on recombinant antigen was not found to be more effective than tests based on whole viral particles.

Antibodies, Viral↗
PubMed1998

[Laboratory diagnosis of Lyme borreliosis].

Some direct methods that can be used for the diagnosis of Lyme borreliosis are the culture, direct visualization or the detection of microbial DNA using polymerase chain reactions, in body tissues or fluids. Unfortunately, all these methods have a low sensitivity. There is a wide assortment of tests and antigens for indirect diagnosis, and the most recommended are ELISA tests and Western blot. The main inconvenient of these tests are the existence of shared serologic reactions, the variability of immune response and the difficult interpretation of results. Therefore, we propose the following guidelines for the diagnosis of Lyme borreliosis: For sero-epidemiological studies and to diagnose infection, antibodies should be determined in subjects with a compatible clinical picture, using an ELISA test that must be positive in at least two separate samples. All positive ELISA results should be confirmed with Western blot analysis, that must be interpreted using established criteria. Polymerase chain reactions should be used when they are available.

Borrelia burgdorferi Group↗
PubMed1998

Subtype distribution among intravenous drug users with chronic type C hepatitis in southern Spain.

The hepatitis C virus (HCV) subtype distribution among intravenous drug users (IVDU), and patients without this risk of acquiring HCV infection, was evaluated. The patients included in the study were 51 with chronic type C hepatitis (36 IVDU and 25 coinfected by HIV-1), and 31 on haemodialysis. Genotyping was performed on 71 viraemic patients, with the following distribution: 25.4%, 1a; 54.9%, 1b; 8.5%, 3a; 7%, mixed (1a, 1b; 3a, 1a; 3a, 1b; 2 x 3a, 2a); 1.4%, 4; and 2.8%, non-typeable. When subtypes were related to IVDU practice, the statistical significance was p < 0.01 for subtypes 1a (48.5% vs 7.5%, for IVDU and non-IVDU, respectively) and 1b (16.1% vs 85.1%). No relation between HIV-1 coinfection and subtype distribution was observed among IVDU patients. The results suggest that among young IVDU of Southern Spain the emerging HCV subtype is 1a.

Antibodies, Viral↗
PubMed1997

Behaviour of IgG antibody avidity for the antigen and of IgA antibody in active cytomegalovirus, Epstein-Barr virus, herpes simplex virus and human herpes virus 6 infections. Adaptation of a commercial test.

The clinical value of specific IgA and IgG antibody avidity to herpes simplex virus, cytomegalovirus, Epstein-Barr virus and human herpes virus 6 for the detection of active disease and primary infection, respectively, was evaluated. The IgG avidity test, with a break point of 55%, for the detection of primary infection, and of the IgA test for the detection of disease, were associated with a sensitivity of 97% and 64%, respectively; specificity of 100% and 82%; a positive predictive value of 100% and 76%; and a negative predictive value of 96% and 72%, respectively.

Adult↗
PubMed1997

Detection of enteroviral RNA by a new single-step PCR.

In this study we present a modified diagnostic routine PCR (polymerase chain reaction) technique for the detection of specific enteroviral nucleic acid sequences in human body fluids, the use of which would reduce the number of false-positive results, the costs and the concentration of reagents required in PCR. Cerebrospinal samples, pharyngeal swabs and faeces were tested. To this end, general primers, selected in the highly conserved 5' non-coding region were used, with a closed-tube RT semi-nested PCR protocol, and the PCR product was analysed using a hybridization in solid phase. A total of 32 patients with suspected enteroviral infection, 17 with suspected viral meningitis and 15 with a possible acute enteroviral infection different from meningitis were analysed, and 80% of the patients with possible acute enteroviral infection were PCR-positive. A broad range of enteroviruses can be detected and false-positive results can be reduced. The availability of results in less than 12 h and the lack of need for radiolabelled probes also increase the convenience of this protocol.

Enterovirus↗
PubMed1997

A comparison of two ELISA methods for the investigation of anti-cytomegalovirus IgG antibodies.

The Alpha-method ELISA for detection of anti-cytomegalovirus (CMV) IgG antibodies (test 1) was compared with another ELISA technique MEIA (test 2). Samples (248 sera and 56 cerebrospinal fluid) from patients with suspected CMV infection were investigated. Discordant samples were re-analysed, undiluted, with a latex test. Positive results were considered to be true positives when there was agreement in the results from the two methods. There were fourteen discrepant samples (4.6%). The latex agglutination test confirmed eight positive for test 1 and six positive for test 2. The overall diagnostic yield of tests 1 and 2 was sensitivity, 91% and 100%; specificity, 99% and 96%; positive predictive values, 95% and 85%; and negative predictive values 98% and 100%, respectively.

Antibodies, Viral↗
PubMed1996

Relationship between viral genotype and viral load in patients with chronic hepatitis C.

To determine the distribution of hepatitis C virus (HCV) genotypes and to related genotype to viral load, genotyping and quantification of viral RNA were carried out in 35 patients with chronic hepatitis C. Subtype 1a was most prevalent (43%), followed by subtypes 1b (23%) and 3a (14%). Mean viral load (log HCV-RNA copies/ml) for subtypes 1b, 1a and 3a was 7.1 +/- 1, 5.6 +/- 1.1 and 4.1 +/- 2.4, respectively. The presence of immunoglobulin M was related to the duration of hepatitis and genotype 1 to a more severe hepatic injury and higher viral load. Differences observed in viral load for a single HCV subtype justify the need to quantify HCV-RNA prior to establishing antiviral therapy.

Analysis of Variance↗
PubMed1996

Diagnosis of cutaneous tuberculosis in biopsy specimens by PCR and southern blotting.

AIMS: To evaluate the use of a gene amplification and hybridisation method for detecting mycobacterial nucleic acid as a possible diagnostic method for cutaneous tuberculosis infection. METHODS: Biopsy specimens from 20 patients with various skin conditions of possible tuberculous aetiology were studied. Six patients had ulcerative nodules, seven lupiform lesions, two non-necrotic granulomas, one scrofulous lichen, one impetigo, one erythematosus lesions, one warty lesions, and one suspected tuberculous lipoma. Biopsy specimens were stained using Ziehl-Neelsen stain and cultured in Lowenstein-Jensen medium. DNA was extracted and then amplified by PCR using primers specific for the Mycobacterium tuberculosis complex. Specificity was confirmed by Southern blotting. RESULTS: Of the specimens, 30% were positive for mycobacteria on staining with Ziehl-Neelsen stain, 60% were culture positive and 85% PCR positive. Only 35.2% of specimens were positive with all three techniques. A further 32.5% were both culture and PCR positive. All PCR negative samples were also negative when cultured or stained with Ziehl-Neelsen stain. Of the PCR positive specimens, 29.4% were negative when cultured or stained. CONCLUSIONS: PCR, using suitable primers, is an efficient and sensitive method for the diagnosis of cutaneous tuberculosis.

Biopsy↗
PubMed1996

Seroprevalence of human toxoplasmosis.

A comparative study of the prevalence of infection by Toxoplasma gondii in Southern Spain in different population groups was carried out using serological markers. The presence of IgG antitoxoplasma antibodies was investigated in serum samples of several population groups. Infection by T. gondii was very prevalent, especially among intravenous drug users (47.6%). An IgG antibody prevalence of 49.6% was obtained from immunocompetent adults with suspected active toxoplasmosis. In infants IgG antibodies were detected in 12.2%, and in pregnant women there was 30% IgG antitoxoplasma antibodies.

Adult↗
PubMed1996

[Superantigens: concept and applications in the pathogenesis and treatment of infectious and autoimmune diseases].

The aim of this study was to review the characteristics of conventional antigens and the way they work, as well as to remark their differences with superantigens. They bind exclusively to the lymphocytic TCR V beta portion, are not processed by macrophages, are related to dependent HLA but not restrained HLA and are able to stimulate a hugh number of lymphocytes, leading them to destruction. Different microorganisms (toxins from S. aureus, S. pyogenes, M. arthritidis, etc. produce a high number of superantigens, which have been associated with infectious diseases, especially by HIV. They have also been related to immunological disorders such as multiple sclerosis, diabetes mellitus, Siögren's syndrome, sarcoidosis, etc. In conclusion, these new molecules will enable us to review the etiology of many diseases and, the most relevant from a clinical point of view, its treatment.

Antigens, Bacterial↗
PubMed1995

Seroepidemiological study of hepatitis E virus in different population groups.

In order to determine the seroprevalence of hepatitis E virus, 1,993 sera (453 from healthy pregnant women, 491 from Moroccan subjects, 492 from blood donors, 321 from children, and 236 from intravenous drug users) were studied. IgG was measured by enzyme immunoassay (EIA), and positive results were confirmed by Western blot. The EIA detected antibodies in 3.96% of the subjects (5.6% of the Moroccans and drug users and 1.8% of the children). Fifty-four percent of these results were confirmed by Western blot, 11.4% were found to be negative, and 34.2% indeterminate. The overall prevalence after confirmation by Western blot decreased to 2.15%. When studying the Western blot pattern of the positive samples, 95% showed antibodies to SG-3, 65% to 8-5, and only 9.3% to CKS fusion protein. In the indeterminate Western blots, the results for these proteins were 96.3%, 62.9%, and 37%, respectively. When the epidemiological data were analysed, no statistically significant differences between women and men or between different age groups were found.

Adult↗
PubMed1995

Three-year study of antibody to Borrelia burgdorferi in southern Spain.

The prevalence of anti-Borrelia burgdorferi antibodies was studied in Granada, Spain, between January 1991 and November 1993 in 354 patients with suspected Lyme disease (group 1); in 50 patients either with syphilis (n = 32) or without syphilis but with a positive Rapid Plasma Reagin test (n = 18) (group 2); and in 150 healthy subjects (group 3). In addition, intrathecal antibody production was evaluated by EIA in CSF samples obtained from 117 patients in group 1. Anti-Borrelia burgdorferi antibodies were detected by EIA in 58 patients (16.4%) in group 1, 29 (8.2%) of whom were positive by Western blot. Intrathecal antibody production was detected in one patient. In group 2, 8 (16%) patients had a positive EIA result, but none of these was confirmed by Western blot. western blot was negative for all subjects in group 3. The results of this study indicate that anti-Borrelia burgdorferi antibodies are not uncommon in our area, although Lyme disease is rare.

Antibodies, Bacterial↗
PubMed1995

Human immunodeficiency virus type-1 can be detected in monocytes by polymerase chain reaction.

Lymphocytes and monocytes from 25 patients infected with human immunodeficiency virus type-1 (HIV-1)--13 asymptomatic, seven with the AIDS-related complex (ARC) and five with the acquired immunodeficiency syndrome (AIDS)--were lysed and subjected to PCR with three primer pairs: SK38/SK39 (gag), SK68/SK69 (env) and SK29/SK30 (LTR). Amplified DNA was solution-hybridised with 32P-labelled probes (SK19, SK70 and SK31, respectively) and detected by PAGE-autoradiography. HIV-1 DNA was detected as follows. Asymptomatic patients: monocytes--gag 61.5%, env 100%, LTR 0%; lymphocytes--gag 100%, env 92.3%, LTR 53.84%. ARC patients: monocytes--gag 71.4%, env 57.1%, LTR 0%; lymphocytes--gag 100%, env 71.4%, LTR 71.4%. AIDS patients: monocytes--gag 80.0%, env 100%, LTR 0%; lymphocytes--gag 100%, env 60%, LTR 60%. The presence of HIV-1 DNA was confirmed in the monocyte fraction. In this cell subset, the env gene-directed primers were the most effective for amplification, whereas the LTR gene-directed primers failed to amplify HIV-1 DNA. The different pattern of amplification found in monocytes may suggest that these cells could be infected by a genetic variant of the virus.

AIDS-Related Complex↗
PubMed1995

Evaluation of enzyme immunoassay for hepatitis B virus DNA based on anti-double-stranded DNA.

We have evaluated a new enzyme immunoassay technology to detect the products of PCR-based amplification that may be applicable to routine testing of hepatitis B virus (HBV) DNA. Two hundred eight serum samples were studied: 73 were basal samples and 135 were sequential serum samples from patients with chronic hepatitis, some of whom were being treated with alpha interferon. We compared the new detection method (PCR-DNA enzyme immunoassay [DEIA]) with dot blot hybridization performed without prior PCR amplification and with two other methods for detection of PCR products: agarose gel electrophoresis with ethidium bromide staining (PCR-EB) and dot blot (PCR-dot blot). For hepatitis B-antigen-positive basal samples, HBV DNA was detected in 70.4% by dot blot, 74.1% by PCR-EB, and 100% by PCR-DEIA and PCR-dot blot; for anti-hepatitis B e-antigen basal samples, HBV DNA was found in 10.5% by dot blot and PCR-EB and in 42.1% by PCR-DEIA and PCR-dot blot. Chi-square tests showed a strong association between dot blot and PCR-EB and between PCR-DEIA and PCR dot blot. Using PCR-dot blot as the reference, dot blot shows a 56.9% sensitivity and a 100% specificity, PCR-EB shows a 55.0% sensitivity and a 100% specificity, and PCR-DEIA shows a 95.4% sensitivity and a 97% specificity. We conclude that the technical advantages of the DEIA method and its high sensitivity and specificity may facilitate the use of PCR in routine testing for HBV DNA in clinical microbiology laboratories.

Base Sequence↗
PubMed1995

[Activation of cell death in lymphocytes from individuals infected with HIV].

BACKGROUND: In HIV infection, T cells depletion cannot only be explained by direct viral infection. Programmed cell death (PCD), also know as apoptosis or activation-induced cell death, may be responsible for the deletion of reactive T cells that contributes to HIV induced immunodeficiency. We studied the response of lymphocytes in vitro to different polyclonal and oligoclonal (superantigen) activators, and tested whether the stimulation of T cells from individual with HIV infection lead to cell death. MATERIAL AND METHODS: Peripheral blood mononuclear cells, total T lymphocytes, TCD4+ and TCD8+ cells from 10 positive patients, 2 patients with AIDS and 10 negative individual for the virus were cultured in RPMI medium and subjected to stimulation with PHA, PWM and SEB (staphylococcus B enterotoxin). Trypan blue was used to distinguish viable from dead cells. RESULTS: TCD4+ cells from HIV-infected patients die after SEB or PWM activation (almost 40% from asymptomatic and 80% from AIDS), and do not die TCD8+ from the same individuals (around 10-15%), or T cells from seronegative controls. CONCLUSIONS: Lymphocytes from patients with HIV-infection showed as abnormal proliferative response to self-MHC class II restricted recall antigens and PWM whereas the response to PHA was conserved. Probably, apoptosis is triggered by an aberrant form of T cell activation in the mature TCD4+ cell population in HIV-infected individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Relationship between the duration of the clinical course of human brucellosis and the avidity of specific IgG antibodies].

The aim of this work was to relate the avidity of specific IgG antibodies with the time of evolution of human brucella infection. IgG anti-brucella antibodies were measured using an ELISA assay with 8 M urea in 17 patients with recent active brucellosis (group I), 31 patients with chronic active brucellosis (group II) and 120 asymptomatic patients with past brucellosis (group III). Twelve patients of group I (70.6%), three of group II (9.7%) and none in group III had low avidity antibodies against Brucella. It is concluded that these antibodies have a high diagnostic efficiency for recent Brucella infections.

Agglutination Tests↗