PubMed Health⌕ Search

Biomedical subjects

A Barral

Publications and source records attributed to A Barral.

At least 73 records · Page 4Linked to original sources
PubMed1988

Visceral leishmaniasis: a disease associated with inability of lymphocytes to activate macrophages to kill leishmania.

1. The production of lymphokines capable of activating macrophages to kill leishmania was evaluated in seven visceral leishmaniasis patients. 2. Macrophages from healthy donors cultivated in vitro with supernatants from lymphocyte cultures of visceral leishmaniasis patients were infected with L. d. chagasi or L. m. amazonensis. After infection the number of amastigotes per 100 cells was counted. 3. The supernatant from visceral leishmaniasis lymphocytes did not significantly reduce the number of intracellular amastigotes of L. donovani chagasi (89 +/- 27%) in relation to controls (culture containing medium alone). In contrast, supernatants of mucocutaneous lymphocyte cultures decreased the percentage of infection to 26 +/- 11%. The supernatant of antigen-stimulated lymphocyte cultures from visceral leishmaniasis patients also did not inhibit L. mexicana amazonensis growth. The supernatant of visceral leishmaniasis lymphocytes stimulated with PHA reduced the number of intracellular amastigotes to 62 +/- 23% in relation to controls. 4. The inability of lymphocytes from visceral leishmaniasis patients to proliferate when stimulated with leishmania antigens and to activate macrophages to kill leishmania may represent a fundamental defect and lead to the acquisition of the disease.

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

Different patterns of disease in two inbred mouse strains infected with a clone of Leishmania mexicana amazonensis.

We have infected BALB/c and C57BL/6 mice with a cloned Leishmania mexicana amazonensis population, obtained from the "Maria" strain. Progression of infection and histopathological examination confirmed the extreme susceptibility of BALB/c mice and the resistant pattern of the C57 BL/6. Anti-Leishmania antibody titers were higher in BALB/c than in C57BL/6 mice through the period of infection. Tests of delayed type hypersensitivity reaction with Leishmania antigens were positive in both strains in the beginning of the infection, but were negative later on in BALB/c mice. Our results are similar to those obtained with mixed parasite populations, and rule out the possibility of selection among different parasite subpopulations as responsible for the divergent course of the disease exhibited by these two strains of mice.

Animals↗
PubMed1986

New perspectives on a subclinical form of visceral leishmaniasis.

During an epidemiological study of visceral leishmaniasis in an endemic region of Brazil, new perspectives emerged on a subclinical form of the disease. A group of 86 children with antibody to Leishmania were identified. None of these children had a history of leishmaniasis. The children were segregated into four groups: One group remained asymptomatic (n = 20), whereas another developed classic kala-azar within weeks of the index serology (n = 15). The remaining 51 patients initially had subclinical disease; 13 (25%) of these patients progressed to classic kala-azar (mean, five months). The others (75%) resolved their illness after a prolonged period (mean, 35 months). The initial illness in the subclinical group was characterized by hepatomegaly, frequent splenomegaly, intermittent cough, diarrhea, and low-grade fever. Malaise and poor weight gain were common. Giemsa-stained smears and cultures of bone marrow aspirates were usually negative for Leishmania in the absence of symptoms of classic kala-azar.

Antibodies↗
PubMed1986

Evaluation of the micro enzyme-linked immunosorbent assay (ELISA) for antibodies in American visceral leishmaniasis: antigen selection for detection of infection-specific responses.

This study was designed to evaluate the ELISA for diagnosis of American visceral leishmaniasis (AVL) using antigen prepared from different Leishmania isolates and from a strain of Trypanosoma cruzi. Two Leishmania donovani chagasi isolates from Bahia and Maranhão (both states of northern Brazil), one L. donovani from Sudan, one L. mexicana amazonensis isolate, and one T. cruzi isolate were used. A total of 375 sera were tested, including 119 from AVL patients, 96 from nonleishmaniasis hospitalized patients, 20 from healthy persons, 30 from patients with mucocutaneous leishmaniasis, 28 from patients with Chagas' disease, 20 from patients with tuberculosis, 21 from leprosy patients, 27 from schistosomiasis patients and 14 from patients with systemic mycoses. The antigens prepared from L. d. chagasi (Bahia) and L. m. amazonensis showed the highest sensitivity (98% and 99%, respectively) for detecting antibodies in sera from AVL patients. However, the specificity of L. d. chagasi (Bahia) antigen was better than that of L. m. amazonensis (96% vs. 86%). Comparison among the three L. donovani isolates demonstrated that the antigen prepared with the isolate from the same area where the sera originated yielded higher mean absorbance than the others. By using spectrophotometric absorbance values it was possible to use a single dilution of serum (between 1/100-1/400) since a clear separation was seen between AVL patients and controls. No patients with the other diseases who were tested gave positive results. We suggest that ELISA can be a very convenient, sensitive, and specific test for diagnosis of AVL when soluble antigen, preferably from an isolate from the test area, is used.

Antibodies↗
PubMed1986

Isolation of Leishmania mexicana amazonensis from the bone marrow in a case of American visceral leishmaniasis.

The first documented human case of visceral leishmaniasis caused by L. mexicana amazonensis is reported. Leishmania were isolated from bone marrow aspirate material from a typical visceral leishmaniasis patient. Further characterization by isoenzyme electrophoresis and by a panel of species- and subspecies-specific monoclonal antibodies established its classification as L. m. amazonensis.

Antibodies, Monoclonal↗
PubMed1986

Suppression of lymphocyte proliferative responses by sera from patients with American visceral leishmaniasis.

We examined the effect of sera from 11 patients with American visceral leishmaniasis on mitogen-driven lymphocyte proliferative capacity. All sera inhibited lymphocyte proliferation of patients' peripheral blood mononuclear cells (PBMC) when stimulated by either phytohemagglutinin, Concanavalin A or pokeweed mitogen. Serum was also strongly inhibitory for Concanavalin A-pulsed normal volunteers' PMBC. The effect of the serum was not due to cytotoxicity, inadequate nutritional support or altered kinetics of DNA synthesis. High levels of IgM or IgG (both total and antiparasite) and high levels of triglycerides were found in patients' sera.

Adolescent↗
PubMed1986

Management of phenotypic female patients with an XY karyotype.

Nine phenotypic female patients with XY karyotype were evaluated through a clinical, cytogenetic, hormonal, endoscopic and histologic diagnostic protocol. Seven patients complained of primary amenorrhea and two patients of abnormal puberal development. The final diagnosis was XY gonadal dysgenesis (n = 5) and testicular feminization syndrome (n = 4). Two patients were less than 155 cm tall, and the remainder were over 155. Minor somatic anomalies were found in two patients with XY gonadal dysgenesis. Patient with testicular feminization syndrome had FSH and LH within the normal range, and patients with XY gonadal dysgenesis had elevated FSH and LH levels. Gonadoblastomas were found in two patients with XY gonadal dysgenesis (one patient with XO/XX/XY mosaicism). Laparoscopy and gonadal biopsy might be useful in some patients to avoid confusion between XY gonadal dysgenesis and testicular feminization syndrome. Early diagnosis of XY gonadal dysgenesis is always desirable, and bilateral gonadectomy is indicated as soon as the diagnosis is made in patients with a Y chromosome and elevated FSH levels. Surgical removal of the gonads from patients with testicular feminization should be delayed until the completion of puberty because of the low risk of malignancy.

Adolescent↗
PubMed1986

Disseminated cutaneous leishmaniasis in a field clinic in Bahia, Brazil: a report of eight cases.

Eight Bahian patients with cutaneous leishmaniasis who had 20 or more ulcerative lesions of short duration are described. Of five identifications of isolated parasites, four were Leishmania braziliensis braziliensis and one was L. mexicana amazonensis. All but one had positive Montenegro tests initially, and all did after treatment. All had circulating anti-leishmanial antibodies and five responded well to glucantime therapy suggesting a functioning immune response. This is quite different to the anergic hansenoid leishmaniasis seen with L. mexicana amazonensis infections in Brazil. Possible reasons for the occurrence of this type of leishmaniasis are briefly discussed.

Adolescent↗
PubMed1984

Gonadal dysgenesis and somatic stigmata in patients with 45,X/46,Xr(X) ring chromosome.

Two cases of gonadal dysgenesis and stigmata of Turner's syndrome with ring chromosome X are described. Their features support the idea that ring chromosome X should be considered as a deletion in the genetic sense, affecting both the gonadal and statural determinants. Without knowing the cytogenetic findings, these patients are usually labeled as having Turner's syndrome. Furthermore, endocrine data and histologic examination of the gonads are indistinguishable from those of individuals with 45,X or 46XX gonadal dysgenesis.

Adolescent↗
PubMed1984

Monocyte suppression of antigen-specific lymphocyte responses in diffuse cutaneous leishmaniasis patients from the Dominican Republic.

Patients from the Dominican Republic with diffuse cutaneous leishmaniasis showed in vivo and in vitro anergy to leishmanial antigen. Relatives of these DCL patients living in the same endemic area frequently showed skin test and lymphocyte reactivity to leishmanial antigens. This further supports the concept of specific anergy in patients with diffuse cutaneous leishmaniasis. Adherent suppressor cells modulate the antigen-specific lymphocyte proliferative response. Suppressor cells could also be isolated by Percoll gradient centrifugation. Co-culturing of lymphocytes and monocytes from HLA-identical leishmanin responders and nonresponders also identified the suppressor cell as a monocyte. In one patient, this suppression disappeared when clinical cure had been accomplished.

Adolescent↗
PubMed1984

Chromosomal complements in primary gonadal failure.

Twenty-nine patients underwent clinical, hormonal, endoscopic, and cytogenetic studies to determine the cause of primary amenorrhea or delayed sexual development. In 19 of them (mean age 17.6 years), the X chromosome was either missing or anomalous. In ten patients (mean age 25.5 years), the chromosomal complement was normal, 46 XX in six patients and 46 XY in four patients. Those with abnormal chromosomal complements were shorter (mean height, 141.9 cm) than patients with normal complements (158.7 cm). Somatic stigmas were observed more frequently in patients with chromosomally abnormal primary gonadal failure. In 23 patients (79.3%), the gonads were streaks, with fibrous stroma devoid of either follicles or tubules containing germ cells. In three patients the ovaries were hypoplastic, with few primordial follicles. Gonadoblastoma was present in two patients with XY and mixed XX/X/XY gonadal dysgenesis. In every patient with streak gonads and lack of germ cells, serum gonadotropin levels were elevated. Karyotype, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) assays, and eventually laparoscopy and gonadal biopsy are important in the management of patients with primary gonadal failure.

Adolescent↗
PubMed1983

Late metastatic Leishmaniasis in the mouse. A model for mucocutaneous disease.

BALB/c, C57B1/6 and (BALB/c x C57B1/6)F1 mice all proved susceptible to infection by a strain of Leishmania isolated from a Central Brazilian with espundia. The course of disease differed markedly between BALB/c and C57B1/6 mice. BALB/c mice suffered from a rapidly progressive and widely metastatic, but non-ulcerative, disease resembling diffuse cutaneous leishmaniasis. In contrast, C57B1/6 mice initially contained parasite multiplication effectively and appeared clinically cured. However, the parasite could persistently be cultured up to about 1 year post-infection. At that time, the parasite load in the infected footpad increased and a patent disease developed characterized by distinctive ulcerative metastases with destruction of soft-tissue in the nasal region similar to the one observed in espundia. Development of disease in both strains of mice was associated with depression of cell-mediated immunity as monitored by delayed-type hypersensitivity in vivo and lymphocyte transformation in vitro. Thus, our study suggests that diffuse cutaneous leishmaniasis and espundia can be caused by the same strain of parasite, and that the particular clinical expression in the individual mouse is determined by the host response.

Animals↗
PubMed1983

Thermosensitivity patterns of Old vs. New World cutaneous strains of Leishmania growing within mouse peritoneal macrophages in vitro.

Infection of mouse peritoneal macrophages in vitro was used to examine the effect of elevated temperature on the intracellular replication of various strains of Leishmania. Of eight cutaneous strains examined, all grew optimally at 35 degrees C. At 37 degrees C the reduction in growth was most pronounced for the New World cutaneous strains, and at 39 degrees C three of four New World cutaneous strains were completely destroyed whereas all of the L. tropica strains survived and exhibited at least 100% growth after 3 days. The results of these in vitro studies correlate closely with the outcome of heat therapy on two patients with cutaneous disease, suggesting that, in general, cutaneous lesions due to L. tropica strains might be less responsive to heat therapy than lesions due to L. mexicana and related strains.

Animals↗
PubMedDate not supplied

Risk factors associated with asymptomatic infection by Leishmania chagasi in north-east Brazil.

Various factors have been associated with a predisposition to the development of clinical American visceral leishmaniasis (AVL). However, little information is available about the factors that predispose to asymptomatic infection. To identify the risk factors associated with asymptomatic infection, a study was carried out between July 1997 and June 1998 on children aged 0-5 years in the districts of Vila Nova and Bom Viver in the municipality of Raposa in the island of São Luís, State of Maranhão, Brazil. A questionnaire containing socioeconomic, demographic and epidemiological data was used. The delayed-type hypersensitivity (DTH) test was carried out on 639 children in the first phase, and on 572 in the second, 7 months after the first survey, using Leishmania amazonensis antigen. Infection was determined by enzyme-linked immunosorbent assay (ELISA) in 638 children during the first phase, and in 572 during the second. Six outcome measures were used: initial prevalence, final prevalence and incidence, each determined by DTH and ELISA. The incidence of infection was 10.8% when determined by DTH and 28.5% when determined by ELISA. After adjustment for confounding variables using Cox regression, infection by L. chagasi was associated with child's age (> or = 2 years), location of the dwellings (Vila Nova) and reporting of relatives with AVL. Bathing outside the house and playing outdoors between 18:00 and 20:00 were identified as risk factors in some analyses but not in others. Presence of intra- and peridomestic Lutzomyia sandflies and animals such as dogs or chickens in the house or in the neighbourhood appeared as risk factors in some analyses but in others they unexpectedly seemed to protect from infection. Malnutrition was not found to be associated with infection.

Animals↗
PubMedDate not supplied

Tegumentary leishmaniasis in childhood.

Very little has been published about tegumentary leishmaniasis in children and there are many controversies about this disorder in the literature. Therefore, we discuss the pathogenesis, clinical aspects, means to diagnosis, and treatment of this endemic disease.

Animals↗
PubMedDate not supplied

Spontaneous regional healing of extensive skin lesions in diffuse cutaneous Leishmaniasis (DCL).

The authors report a case of diffuse cutaneous leishmaniasis, with longstanding evolution and presenting with diffuse infiltrated lesions rich in amastigotes in the absence of mucosal involvement. In situ characterization with monoclonal antibodies revealed Leishmania amazonensis. Large regional lesions have presented spontaneous healing without specific therapy. Considering that DCL presents with a defect in the cellular immune response, this fact demonstrate that this patient may develop a regional cellular immune response enough to destroy the parasites and to produce clearing of some lesions.

Child↗