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Biomedical subjects

L A Freitas

Publications and source records attributed to L A Freitas.

18 recordsLinked to original sources
PubMed2005

Body mass index and waist circumference in non-alcoholic fatty liver disease.

OBJECTIVE: To evaluate the association of anthropometric indexes (body mass index and waist circumference) in patients with non-alcoholic fatty liver disease (NAFLD), and its association with insulin resistance (IR), metabolic syndrome (MS) and histological findings. METHODS: From August 2003 to July 2004 a case series of 81 outpatients with clinic and/or histological diagnosis of NAFLD were selected at the Bahia University Gastro-Hepatology Clinic, Brazil. Liver function tests, lipid profile, glucose and insulin were performed in all patients. Body mass index (BMI) and waist circumference (WC) were determined according to WHO criteria. IR was measured by means of the homeostasis model assessment (HOMA) and IR was considered with HOMA > or =3. MS was defined according to the Adult Treatment Panel III (ATP III). Liver biopsy was performed in 37 cases. RESULTS: Body mass index > or = 30 kg m(-2) (obesity) was found in 39% of the cases and BMI > or = 25-29.9 kg m(-2) (overweight) in 53%. BMI was correlated with IR (r = 0.29; P = 0.02) and WC with ALT (r = 0.02; P = 0.03). Increased WC also was related to IR and to MS. The presence of steatohepatitis with fibrosis on liver biopsy was associated with overweight (68%) and increase of WC (41%). CONCLUSIONS: Body mass index and WC are frequent associated with MS, IR and histological findings (steatohepatitis and fibrosis) in patients with NAFLD.

Adult↗
PubMed1999

Nonalcoholic steatohepatitis: a toxic liver disease in industrial workers.

AIMS: Occupational/environmental exposure to hepatotoxins has recently been implicated in nonalcoholic steatohepatitis (NASH). The aims of this study were to determine the presence and frequency of NASH in a large group of workers chronically exposed to several volatile petrochemical products in an industrial area in north-east Brazil and to observe its course in workers removed from the work environment. METHODS: 1500 asymptomatic workers were screened with standard liver blood tests during 1994-5. Those with elevated transaminases (>3x normal) on 3 occasions were evaluated further both clinically and with serum HBsAg, anti-HCV, ferritin, lipids and autoantibody determination. Patients with either no etiological diagnosis, positive HBsAg/anti-HCV serology and/or excess alcohol intake underwent liver biopsy. Those with obesity, diabetes or an isolated abnormal GGT were excluded. Of workers diagnosed as having NASH (compatible histology and no excess alcohol intake), a proportion were removed from the work environment and evaluated monthly with liver blood tests and a repeat liver biopsy 8-14 months later. RESULTS: 112 workers had abnormal transaminases and 32 fulfilled the criteria for liver biopsy. 20 of these were classified as NASH, the remainder had viral hepatitis (n = 6), alcoholic liver disease (n = 5) or portal vein thrombosis (n = 1). In all of the 10/20 who were removed from the work environment, their aminotransferases and GGT gradually decreased and their histology improved. CONCLUSIONS: These results demonstrate that NASH can occur following chronic exposure to volatile petrochemical substances in the workplace. Exposed workers should be regularly screened for the presence of liver damage and ideally removed from the work environment where possible.

Adult↗
PubMed1996

A cross-sectional serodiagnostic survey of canine leishmaniasis due to Leishmania chagasi.

Jequie, a community of about 144,500 inhabitants located in the State of Bahia, Brazil, is endemic for both visceral and cutaneous leishmaniases. In the present epidemiologic study, the urban and inhabited periurban areas of the town were divided into 140 clusters of 0.25 km2 each. The seroprevalence of canine Leishmania antibodies was investigated using an enzyme-linked immunosorbent assay as a screening test since its sensitivity was significantly higher than that of an indirect immunofluorescence assay. A total of 1,681 dogs was surveyed in 34 randomly sampled clusters. The overall prevalence of Leishmania antibodies in the dog population was 23.5%, with intracluster prevalences ranging from 0% to 67%. There was no correlation of these seroprevalences with the intracluster densities of canine populations, or with the distances from individual clusters to the town center. Moreover, the Leishmania transmission did not seem to follow any clear-cut spatial pattern, since large disparities in the seroprevalences of contiguous clusters were found. Curiously, human cases of visceral leishmaniasis have never been observed in some clusters with a relatively high prevalence of canine seroprevalences. Eight parasite isolates from seropositive dogs were found to belong to the same serodeme and zymodeme as Leishmania (L.) chagasi. The implications of these findings with respect to the epidemiology and control of American visceral leishmaniasis are discussed.

Animals↗
PubMed1992

Leishmania amazonensis infection: a comparison of in vivo leishmanicidal mechanisms between immunized and naive infected BALB/c mice.

In vitro studies have shown that both macrophage activation and destruction of parasitized macrophages lead to leishmania destruction. The relative role played by such mechanisms in vivo have not been properly evaluated. We took advantage of the model of intravenous immunization with solubilized leishmanial antigen which renders partially resistant the otherwise highly susceptible BALB/c mice to address this issue avoiding the interference of different genetic backgrounds. Leishmania destruction occurred in three situations: destruction of the parasitized macrophage, which were in close contact with lymphocytes or eosinophils; extracellular damage, always surrounded by small foci of granulocytes; and parasite damage inside activated macrophages. Destruction of the parasitized macrophages was frequently seen in immunized and protected animals. Our observations suggest that destruction of parasite-loaded macrophages is an important mechanism of host protection in experimental cutaneous leishmaniasis.

Animals↗
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↗
PubMed1991

Granulocytes in the inflammatory process of BALB/c mice infected by Leishmania amazonensis. A quantitative approach.

We used previously immunized (partially resistant) and naive (highly susceptible) BALB/c mice infected with Leishmania amazonensis for evaluating the role of granulocytes in the course of murine leishmaniasis. The animals were examined at different times post-infection and granulocytes counted in lesion tissues examined ultra-structurally. Polymorphonuclear granulocytes predominated during the early phase of infection and their number decreased with progression of infection; their number was similar in both groups during the early and intermediate phases of infection, though slightly higher in immunized animals during the late phase. Eosinophils represented approximately 10% of cells in the inflammatory infiltrate, being higher during the intermediate phase, and not differing between the groups. Another approach was the evaluation of granulocyte migration to the peritoneal cavity of susceptible BALB/c mice or resistant C57BL/6 mice under several stimuli. There was no statistically significant difference between resistant and susceptible animals in any of the treatments. Despite the influx of granulocytes to the lesion and its possible role in the initial destruction of injected Leishmania, this aspect does not seem to have an important effect on the outcome of the leishmanial infection.

Animals↗
PubMed1991

Variations in susceptibility to Leishmania amazonensis infection in lines of mice selected for high or low immunoresponsiveness.

The degree of resistance to a local Leishmania amazonensis challenge has been compared in lines of mice obtained by selective breeding for high or low immunoresponsiveness: High and Low antibody responder mice of Selections I and II (HI, HII and LI, LII lines) and high and low responder mice to T mitogen PHA (Hi/PHA and Lo/PHA). The aim of this preliminary study was to focus attention on genetic differences related with well defined immune characteristics. Clear-cut results were obtained, both HI and HII mice developed large and disseminating lesions, the rate of symptom aggravation being faster in HII, while LI and LII proved resistant to parasites, only small and transient lesions being observed for them during a 150 days follow up. The outcome of infection also differs in Hi/PHA and Lo/PHA mice, Hi/PHA having a resistant and Lo/PHA a susceptible phenotype.

Animals↗
PubMed1991

Experimental chemotherapy of Trypanosoma cruzi infection: persistence of parasite antigens and positive serology in parasitologically cured mice.

Mice infected with Trypanosoma cruzi, but parasitologically cured after specific chemotherapy, continued to exhibit positive indirect immunofluorescence serological tests 3-6 months after the therapy. Treatment of trypanosome antigens with monospecific antisera produced in rabbits, and examination by immunoelectron-microscopy following peroxidase labelling disclosed the presence of membrane deposits in cell processes in the spleens of the mice. Similar deposits were observed in the external membranes of T. cruzi amastigotes in the spleens of acutely infected mice, but not in normal control mice. No reaction occurred in tissues not previously treated with the monospecific anti-T. cruzi serum. Positive cells in treated and cured mice, as well as in the not cured or untreated control mice, were located in germinal centres of the splenic white pulp and presented long and branching cytoplasmic processes, which are indicative of dendritic cells of the lymphoid follicles of the spleen.

Animals↗
PubMed1989

Iron, zinc, folate and vitamin B12 nutritional status and milk composition of low-income Brazilian mothers.

The purpose of this study was to assess the nutritional status of low-income Brazilian mothers, who were supplemented with iron and vitamin B12 during pregnancy, in terms of iron, zinc, folate and vitamin B12, in different stages of lactation and to determine the influence of the maternal nutritional status on milk composition. The effect of folate supplementation during pregnancy on folate status of the nursing mothers and milk composition was investigated. The effect of partial weaning on maternal status and milk composition was also studied. In general, the nutritional status of iron, zinc, folate and vitamin B12 of the mothers appears adequate. However, some of the mothers had indices of status lower than normal limits for non-pregnant women. These values, particularly after 30 d post-partum, indicate that these mothers might be at nutritional risk and that the nutrient supplementation received during pregnancy was insufficient to meet demands. There was an increase with the stage of lactation for haematocrit, serum vitamin B12, serum zinc, serum albumin, milk folate and saturation of its binding protein, but there was a decrease for milk protein, total and whey-bound iron and zinc, and lactoferrin. Mothers who took folate supplements during pregnancy had higher serum folate levels immediately after birth than those not taking the supplements but no differences were found at later stages of lactation. Milk composition was not affected. Partial weaning did not affect the maternal nutritional status or the milk composition except for iron which was higher in milk from mothers who were partially breastfeeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Brazil↗
PubMed1988

Differences in hepatic pathology resulting from bile duct obstruction in young and old rats.

1. Young and adult rats subjected to complete bile duct ligation from 4 to 40 days revealed different liver histopathologies at the end of the experimental period. 2. In young rats, ductal and ductular proliferation resulted in septal fibrosis which, originating from the portal spaces, tended to delimit areas of nodular parenchymal transformation (secondary biliary cirrhosis). In adult rats, proliferating ductal and ductular structures diffusely invaded the hepatic parenchyma, dissociating the liver cell plates in a pattern similar to that of a malignant neoplastic growth. 3. The different result of the lesions in young and old rats suggests that an age-related factor may be involved in the pathogenesis of lesions resulting from biliary obstruction.

Age Factors↗
PubMed1988

Concentration and distribution pattern of selected micronutrients in preterm and term milk from urban Brazilian mothers during early lactation.

The purpose of this study was to assess the concentration and binding pattern of zinc, iron, folate and vitamin B12 in milk of Brazilian women of low socioeconomic status giving birth at term or preterm, during early lactation. Protein, fat, total solids and ash concentrations were also determined. Protein and zinc concentrations decreased significantly as lactation proceeded whereas milk fat and folate increased with the lactation period. Total solids, ash, iron and vitamin B12 remained unchanged. Zinc was present mainly in the whey fraction while less than half of the total iron was present in this fraction, with no significant change due to stage of lactation. Unsaturated folate and vitamin B12 binding capacities and percentage of saturation of the folate binding protein increased with the stage of lactation. The vitamin B12 binding protein was highly unsaturated in all samples. There was no significant difference between term and preterm samples in the parameters investigated. Correlation analysis between milk components indicated significant relationships between total solids and fat, total zinc and whey zinc, folate and total folate binding capacity, unsaturated and total folate binding capacity, and unsaturated and total B12 binding capacity. In general, the nutrient concentrations found in this study are in good agreement with published data on milk composition of women from developed countries, with the possible exceptions of folate, which was lower, and iron, which was higher. The correlation of folate concentration with its binding protein found in this work supports the hypothesis of a regulatory role for folate levels in milk exerted by the folate binding protein in the mammary gland.

Adolescent↗
PubMed1987

Therapeutic action of MK-436 (2,5-nitroimidazole) on Trypanosoma cruzi infections in mice: a parasitological, serological, histopathological, and ultrastructural study.

The anti-protozoal drug MK-436 (3-(1-methyl-5-nitroimidazol-2-yl)-3a,4,5,6,7,7a-hexahydro-1,2-benzisoxazole) was found to be effective against Trypanosoma cruzi infections in mice (2 daily doses of 250 mg per kg body weight). Parasitaemia disappeared within 24 hours of treatment which was commenced during the early or late stages of acute infection. Intracellular T. cruzi parasites were also affected by the drug, ultrastructural findings showing severe cytoplasmic vacuolization and membrane alterations. Positive serological responses persisted in the majority of treated and parasitologically cured mice in the study. Cure rates varied from 72% to 100% and were similar regardless of the T. cruzi strain used (Y strain, type I; 12 SF strain, type II; or Colombian strain, type III). However, the proportion of positive serological tests and the frequency of inflammatory lesions were greatest for mice that were infected with the Colombian strain of the parasite.

Animals↗
PubMedDate not supplied

Leukocyte, platelet and endothelial activation in patients with acute renal failure treated by intermittent hemodialysis.

BACKGROUND: Using different types of dialysis membranes to treat acute renal failure (ARF), clinical and experimental studies have demonstrated discordant results relatively to the effect of membrane bioincompatibility on patient outcome. Nevertheless, there are few data on the biocompatibility indices in patients with ARF who need to be treated by hemodialysis. OBJECTIVE: To characterize the impact of intermittent hemodialysis (IHD) on indices of leukocyte, platelet and endothelial activation in patients with ARF. PATIENTS AND METHODS: We prospectively studied 27 patients with severe ARF treated by IHD. They were characterized relatively to gender, age, ARF etiology, urinary output per 24 h, Simplified Acute Physiology Score (SAPS), number of dialysis sessions and outcome. We evaluated the effect of hemodialysis with two types of low-flux dialyzers (cuprophane and polysulfone dialyzers) on plasma concentrations of soluble TNF-RI (TNF-sR55), TNF-RII (TNF-sR75), interleukin (IL)-6, soluble CD23 molecule, soluble P-selectin and von Willebrand factor (vWF). RESULTS: There were no significant differences between the two groups of patients dialyzed with cellulose-based and synthetic membranes in terms of age, sex, urinary output per 24 h, SAPS, number of dialysis sessions and mortality. We verified high plasma concentrations of TNF-sR55, TNF-sR75, IL-6, sCD23, sP-selectin and vWF in the global population studied. Patients dialyzed with cuprophane membranes showed significantly lower pre- and postdialysis concentrations of sP-selectin than patients dialyzed with polysulfone membranes. After a hemodialysis session, with correction for differences of blood hematocrit, we did not observe any significant modification in the concentrations of TNF-sR55, TNF-sR75, IL-6, sP-selectin and vWF of the plasma. On the other hand, a significant increase of sCD23 molecule was found in the group dialyzed with polysulfone membranes (p = 0.009). CONCLUSIONS: The group of 27 patients with ARF who needed IHD, showed increased plasma concentrations of some leukocyte, platelet and endothelial activation markers (TNF-sR55, TNF-sR75, IL-6, sCD23, sP-selectin and vWF). These mediators characterize the inflammatory and procoagulant state associated with this pathologic condition. After a hemodialysis session with these low-flux membranes (cellulose-based and polysulfone membranes), we did not observe any significant variation in the concentrations of TNF-sR55, TNF-sR75, IL-6, sP-selectin and vWF of the plasma. Patients dialyzed with polysulfone membranes presented higher basal plasma concentrations of sP-selectin and significant postdialysis increase of plasma concentrations of CD23 molecule compared to patients dialyzed with cuprophane dialyzers.

Acute Kidney Injury↗
PubMedDate not supplied

Hyperplasia of elastic tissue in hepatic schistosomal fibrosis.

Elastic tissue hyperplasia, revealed by means of histological, immunocytochemical and ultra-structural methods, appeared as a prominent change in surgical liver biopsies taken from 61 patients with schistosomal periportal and septal fibrosis. Such hyperplasia was absent in experimental murine schistosomiasis, including mice with "pipe-stem" fibrosis. Displaced connective tissue cells in periportal areas, such as smooth muscle cells, more frequently observed in human material, could be the site of excessive elastin synthesis, and could explain the differences observed in human and experimental materials. Elastic tissue, sometimes represented by its microfibrillar components, also appeared to be more condensed in areas of matrix (collagen) degradation, suggesting a participation of this tissue in the remodelling of the extracellular matrix. By its rectratile properties elastic tissue hyperplasia in hepatic schistosomiasis can cause vascular narrowing and thus play a role in the pathogenesis of portal hypertension.

Adolescent↗