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Biomedical subjects

J M Costa

Publications and source records attributed to J M Costa.

At least 73 records · Page 4Linked to original sources
PubMed1993

Detection of Toxoplasma gondii by competitive DNA amplification of bronchoalveolar lavage samples.

The prevalence of pulmonary toxoplasmosis was assessed by a prospective analysis of 144 bronchoalveolar lavage (BAL) samples using competitive polymerase chain reaction (PCR) to avoid false-negative results due to PCR techniques. Six samples were excluded because they contained amplification reaction inhibitors. None of the samples from the 37 immunocompetent patients and only 1 sample (1.7%) from the 59 immunocompromised patients without human immunodeficiency virus infection were PCR-positive. In contrast, Toxoplasma gondii DNA was found in 6 (14%) of 42 samples from patients with AIDS. All 6 patients had < or = 40 CD4 cells/microL and anti-Toxoplasma antibodies, and 5 had other sites of Toxoplasma infection. Six other AIDS patients who had received treatment for cerebral toxoplasmosis were PCR-negative. Thus, pulmonary toxoplasmosis is frequent in AIDS patients who have other sites of Toxoplasma infection and low CD4 lymphocyte counts and who are not receiving prophylaxis.

Adolescent↗
PubMed1993

Detection of a molecular defect in 40 of 44 patients with haemophilia B by PCR and denaturing gradient gel electrophoresis.

Oligonucleotides were computer designed to amplify by the polymerase chain reaction (PCR) the coding region, splice junctions, 112 bp of the 5' flanking region and 279 bp surrounding the polyadenylation site of the factor IX gene for analysis by denaturing gradient gel electrophoresis (DGGE). Forty-four unselected haemophilia B patients were studied of whom 24 had severe haemophilia and 20 had a mild to moderate form of the disease. Potential mutations were identified in 40 (91%) of the 44 cases. A defect could not be detected in three severe and one mild haemophiliac by DGGE analysis and direct sequencing of all the PCR fragments from these patients revealed no nucleotide alteration supporting the DGGE results. A total of 37 point mutations, two complete gene deletions and a duplication of 26 bp were found. The 37 point mutations included 35 single nucleotide substitutions, a deletion and an insertion of one nucleotide. The 35 single nucleotide substitutions included 26 missense mutations, seven nonsense mutations, a G (-6) to A transition in the promoter region and a G (30154) to A transition within the donor splice site of the last intron. Fifteen of these nucleotide substitutions involved CpG dinucleotides. Fifteen point mutations were found at codons where nucleotide substitutions had not been detected before. An insertion of a single nucleotide T at position 6370 and deletion of a G at nucleotide 30845 resulted in frameshift mutations creating stop codons at amino acid positions -2 and 250, respectively. A duplication of 26 bp (17747-17772) in exon V was found in a severe haemophilia patient resulting in a termination codon in exon VI. The detection of the mutation by the combined use of PCR, DGGE and direct sequencing was important for carrier diagnosis of 20 families with no prior history of haemophilia B.

Amino Acids↗
PubMed1993

Leishmaniasis recidiva cutis in American cutaneous leishmaniasis.

BACKGROUND: Leishmaniasis recidiva cutis (LRC) consists of active lesions around or inside the scar of classical cutaneous leishmaniasis (CL). In the literature it is considered as an hyperergic form of CL because the patients show a strong response to intradermal testing with leishmania antigen and, histologically, the parasites are scarce or absent; a well-organized granuloma is always observed. METHODS: Three patients from Bahia (Brazil) with LRC were evaluated by clinical examination, biopsies, skin tests with leishmania antigen, serology, and culture. In addition, a specific lymphocyte blastogenesis test was done and the species of leishmania characterized. RESULTS: The disease was caused by both L. amazonensis and L. braziliensis and serological titers varied from 1/16 to 1/64. The patients presented histologic and immunologic aspects different from those referred to in the literature. From four biopsies obtained only two presented a granulomatous reaction and parasites varied from absent to a parasite index 3. In one patient an absence of T cell response to leishmania antigen was observed in the first evaluation with restoration of the response after cure. In the other two, the degree of the specific proliferative response was lower than that usually observed in patients with classical CL. CONCLUSIONS: These findings indicate that New World LRC can not be considered a hyperergic form of CL. With respect to its clinical aspects and response to treatment, LRC must be considered as an entity different from the classical CL.

Adult↗
PubMed1992

XY sex reversal associated with a deletion 5' to the SRY "HMG box" in the testis-determining region.

The human testis-determining factor resides within a 35-kilobase (kb) region of the Y chromosome immediately adjacent to the pseudoautosomal boundary. A candidate gene for human sex determination (SRY) was isolated in this region. Here, we describe a study of 25 cases of XY females with pure gonadal dysgenesis for mutations on the Y chromosome short arm, including SRY. Southern blotting revealed a sex-reversed female harboring a deletion extending from approximately 8 kb from the pseudoautosomal boundary of the Y chromosome to at least 33 kb and no more than 60 kb upstream, toward the centromere. The deletion begins no more than 1.8 kb upstream from the first ATG of the SRY open reading frame present in the clone pY53.3. To our knowledge, no mutation has been described previously outside the SRY "HMG box" on the short arm of the Y chromosome, which is associated with sex reversal. Since the 5' extent of the SRY transcriptional unit has not been defined, the deletion may remove upstream exons of SRY and/or transcriptional regulatory motifs, either situation resulting in lack of testicular development. It cannot be formally excluded that the mutation removes a second locus, independent of SRY, that is critical for sex determination. Denaturant gradient gel electrophoresis analysis of the SRY open reading frame in the remaining 24 cases revealed de novo single base-pair transitions in the SRY conserved domain in 4 cases.

Amino Acid Sequence↗
PubMed1992

Partial characterization of an autoantibody recognizing the secondary binding site(s) of thrombin in a patient with recurrent spontaneous arterial thrombosis.

A patient with an 18 year history of recurrent arterial thrombosis and no evidence of atherosclerosis or embolism of cardiac origin presented with a prolonged thrombin clotting time when performed with human thrombin. The bovine thrombin clotting time was only slightly prolonged. During 30 months of follow-up, the thrombin time fluctuated, but remained prolonged. The patient has been treated with an oral anticoagulant for the past 8 years, with no thrombotic recurrence. The inhibitor activity was due to the presence of polyclonal IgGs which bound to thrombin-Sepharose. The influence of IgGs purified from the patient's serum was compared to the influence of normal IgGs in several systems exploring the catalytic activity of thrombin and the binding of the enzyme to macromolecular substrates through secondary binding site(s). We found that the IgGs did not impair the catalytic activity toward small synthetic substrates, but inhibited the binding of thrombin to fibrinogen, thrombomodulin and heparin cofactor II. Such proteins are known to require a secondary binding site of thrombin to interact with the enzyme. The anti-thrombin antibody might have resulted from an abnormal generation of thrombin. This would be the consequence of the process favouring thrombosis. Alternatively, the autoantibody might have favoured thrombosis primarily, by impairing natural antithrombotic mechanisms triggered by thrombin.

Adult↗
PubMed1992

An enzyme-linked immunosorbent assay for heparin cofactor II (HCII). Application to the measurement of HCII in clinical materials.

Heparin cofactor II (HCII) is a thrombin inhibitor in human plasma, the activity of which is enhanced by heparin and dermatan sulfate. To measure the plasma antigen concentration of HCII, an enzyme-linked immunosorbent assay (ELISA) has been developed, and this is based on the use of polyclonal anti-HCII IgG, both as the antigen-capturing antibody and as the labelled antibody. The intra- and inter-assay reproducibilities have been calculated to be less than 6%. HCII antigen concentrations evaluated with this ELISA technique in clinical plasma samples correlated well with those determined by electroimmunodiffusion and with HCII activities evaluated using a functional assay (r = 0.909 and r = 0.930, P less than 0.0001). Since the correlation between HCII deficiency and thrombosis is still a controversial issue, the ELISA technique described in this report could be a useful tool for the large-scale studies needed to determine the prevalence of HCII deficiency in healthy individuals and in patients with a history of thrombosis.

Adult↗
PubMed1992

Diffuse cutaneous leishmaniasis with atypical aspects.

A 16-year-old man had long-standing diffuse cutaneous leishmaniasis with the following characteristics: diffuse infiltrated lesions rich in amastigotes, absence of mucosal involvement, and lack of parasite-specific cell-mediated immune response. In situ identification of Leishmania mexicana amazonensis was achieved by the use of monoclonal antibodies. Clinically, as an atypical finding there was deep and extensive ulceration in the lower limbs. Histologically, an atypical characteristic was the presence of a high number of eosinophils in the infiltrate predominantly in the ulcerated lesion. Ultrastructurally, parasitized and lysed eosinophils with dispersion of their granules were seen in the vicinity of parasitized or lysed macrophages.

Adolescent↗
PubMed1992

[Bionomic studies of Dipetalogaster maximus (Uhler, 1894) (Hemiptera, Reduviidae, Triatominae). III. Population dynamics].

A population dynamics study of D. maximus was carried out under laboratory conditions (28 degrees C e 65% +/- 5% U.R.), and the methodology was the same that has been used for rearing these insects. In order to evaluate the population growth rate of this species, during a 24 months period, five colonies started with a couple recently emerged were observed. Each couple (a male and a female) was maintained in a glass container measuring 20 cm of diameter and 20 cm in height with filter paper on the bottom. The insects were monthly feeding with normal mice blood, and at this day the number of eggs, nymphal stages and adults was registered. All graphical representations of the populations growth showed the same shape. It was found that the average of nymphal stage represented 64.3% of the holè population whereas the oviposition curve showed to be inverse to this one (28.57%) a small percentage of adults was found: males 3.85% and females 3.12%. In this study observations on the biological cycle, longevity and fertility rates were also carried out.

Animals↗
PubMed1991

Heparin cofactor II deficiency in renal allograft recipients: no correlation with the development of thrombosis.

Heparin cofactor II (HC II) is a thrombin inhibitor in human plasma which displays great similarities with antithrombin III (AT III). Hereditary HC II deficiency was recently reported to be associated with thrombophilia. Since thromboembolism constitutes an important post-operative complication after renal transplantation, we measured HC II and AT III in the plasma of 118 healthy renal allograft recipients (RAR) and found stable low HC II and high AT III levels. Administration of azathioprine (AZA), cyclosporine A (CSA) or both as immunosuppressive therapy did not affect HC II levels, but CSA seems to have raised plasma AT III. The proportion of patients with HC II deficiency was significantly higher in RAR than the proportion we previously found (11) in healthy individuals (16.9% vs 1.5%). However, the proportions with low plasma HC II were not different in healthy RAR and in ten RAR with thrombotic events, suggesting that in transplanted patients, HC II deficiency is not in itself a risk factor for the development of thrombosis.

Adolescent↗
PubMed1990

[Treatment of neurocysticercosis with praziquantel].

Twenty seven patients with neurocysticercosis were treated with praziquantel in progressive doses reaching 50 mg/kg/day associated with dexamethasone for 21 days. The patients were followed during and after treatment and those followed up for one year repeated their immunological tests (indirect immunofluorescence and ELISA) at this time. Headache was the most frequent symptom during the treatment, occurring on 37% of patients. During the treatment 18.5% of patients had intracranial hypertension and one died. One year after treatment 72.2% of patients who finished treatment improved. The immunological tests became negative in 45.4% of patients sera and 42.8% of cerebrospinal fluids. There was no correlation between the clinical evolution and immunological tests. In this study it is not possible to affirm that both negative immunological tests and good clinical evolution were consequent to the efficacy of praziquantel treatment. Due to the great frequency and seriousness of this treatment complications, the patients with neurocysticercosis must be individually evaluated to know the risks and the benefits of the treatment with praziquantel.

Adolescent↗
PubMed1987

Evaluation of T-cell subsets in the lesion infiltrates of human cutaneous and mucocutaneous leishmaniasis.

We have characterized the T-lymphocytes in the skin lesions of 10 patients with cutaneous leishmaniasis and in the nasal lesions of seven patients with mucosal leishmaniasis, with the immunoperoxidase and monoclonal antibody techniques. There was predominance of cells with helper phenotype (Leu 3A+ 3B) over suppressor phenotype (Leu 2a) in the lesions of both groups. The helper/suppressor (H/S) ratio in the skin lesions was 1.6 +/- 0.5 and in the nasal lesions of mucosal leishmaniasis was 1.7 +/- 0.8. The H/S ratios in the peripheral blood of patients with cutaneous leishmaniasis (2.1 +/- 0.8) and in patients with mucosal leishmaniasis (1.6 +/- 0.8) were comparable and similar to the ratios in the skin and nasal biopsies. The percentage of T-cells and macrophages expressing the Dr antigen in the cutaneous group (69.5 +/- 13.7) was not significantly different from the mucosal patients (90.3 +/- 5.7). We conclude that the immunopathology of the skin lesions in cutaneous leishmaniasis is similar to the nasal lesions of mucosal leishmaniasis.

Adolescent↗
PubMed1987

[Vesico-ureteral reflux in patients with neurogenic bladder dysfunction: causes, types, treatment, development and results].

Thirty one patients, suffering from vesicoureteral reflux, were selected from a group of 106 children affected by neurogenic bladder dysfunction. The causes of neurogenic dysfunction (26 a sequel of spina bifida, 2 agenesis of sacrum and 3 medullar tumors) and grade and type of reflux in the 47 reno-ureteral units (I, 4; II, 20; III, 6; IV, 11, and V, 6) are described. The treatment was medical, combining different bladder expression methods, in 11 ureters, medical plus intermittent catheterization in 36 and surgical in 14. The analysis of the results were: Satisfactory because of complete cure or improvement of the reflux in 35 ureters, un satisfactory in 5 (3 patient died and 2 were diverted and indeterminate in the other 7, whose reflux remained unchanged whose follow up was too short.

Adolescent↗
PubMed1987

Antimony accumulation in hair during treatment of leishmaniasis.

We used instrumental neutron activation analysis (INAA) to determine antimony in small quantities of hair from individuals living in an area of endemic leishmaniasis. The groups studied were 12 patients undergoing treatment with N-methylglucamine antimoniate, 34 patients who had received such treatment a year ago, and 17 control subjects (untreated) who were living in the same area. Patients receiving treatment showed mean and median (12.13, 2.9 micrograms/g) values for antimony in hair that significantly exceeded those in either controls (1.01, 0.4 microgram/g) or patients one year after treatment (1.54, 1.0 microgram/g). We conclude that INAA can be useful in monitoring and differentiating such exposure to antimony in patients under treatment.

Antimony↗
PubMed1986

[Immunoenzymatic test (ELISA) in the diagnosis of neurocysticercosis: study of various antigenic extracts in the detection of IgG antibodies in serum and cerebrospinal fluid samples].

Five different antigens from Cysticercus cellulosae, a vesicular fluid, a saline and an alkaline total extracts, an escolex and membrane, were studied in the ELISA immunoenzymatic assay to demonstrate IgG antibodies in cerebrospinal fluid (CSF) and serum samples. For the 5 antigens the 20 micrograms/ml concentration was selected for polyvinyl plates sensitization for CSF and serum assays. The IgG fraction of a sheep anti-human IgG antiserum was labeled with horseradish peroxidase and revealed with hydrogen peroxide-5-aminosalicilic acid. For positive results 10 ELISA Units for sera and 5 EU for CSF were taken. A total of 182 serum samples and 115 CSF samples were tested. The ELISA sensitivity for sera were 88.6% for vesicular fluid, escolex and membrane; 85.7% for saline extract and 62.8% for alkaline extract. The ELISA sensitivity for CSF was 100% for vesicular fluid and saline total extract, 91.7% for membrane, 89.6% for excolex and 77.1% for alkaline. The ELISA specificity for sera was 100% to the 5 antigens studied; to the CSF was 100% for the alkaline and escolex and 98.5% for the other antigens. An ELISA geometric mean titer of sera and CSF was respectively the 121.1 and 27.3 for vesicular fluid, 111.6 and 31.1 for saline total extract, 30.3 and 5.3 for alkaline total extract, 63.2 and 14.8 for escolex and 69.1 and 18.8 for membrane antigen. ELISA was then compared to immunofluorescence, hemagglutination and complement fixation tests in CSF and sera. ELISA immunoenzymatic assay with saline total extract is recommended for the easy preparation and for the high quantity of antigens obtained, for the high sensitivity and great specificity for sera and CSF; we suggest that this test may be used as a substitute for immunofluorescence, hemagglutination and complement fixation in sera or CSF for the diagnosis of neurocysticercosis.

Antigens, Helminth↗