Biomedical subjects

F S Moreno

Publications and source records attributed to F S Moreno.

10 recordsLinked to original sources

PubMed2006

Protective effects of guarana (Paullinia cupana Mart. var. Sorbilis) against DEN-induced DNA damage on mouse liver.

Guarana (Paullinia cupana Mart. var. Sorbilis) is a plant originally from Brazil, which is rich in tannins. Some tannins are known to present protective effects against DNA damage. This study was performed to investigate the anti-genotoxic/cytotoxic properties of guarana in hepatocytes of mice injected with N-nitrosodiethylamine (DEN). The protective effect of guarana was evaluated both by comet assay and DNA smear fragmentation technique in two month-old female BALB/c mice. These were treated previously with 2.0 mg/g bw of guarana for 16 days and then injected with DEN (160 microg/g body weight) to induce DNA damage. The DEN-only treated group presented higher comet image length than the guarana plus DEN and untreated groups (116.06+/-5.0 microm, 104.09+/-3.3 microm and 93.28+/-14.4 microm, respectively; p<0.01). Guarana treatment presented a 52.54% reduction in comet image length when animals were exposed to DEN (p<0.05). DNA samples from the guarana plus DEN group clearly showed less EtBr fluorescence intensity when compared to the DEN-only group, reinforcing the comet assay data. These results show, for the first time, that guarana has a protective effect against DEN-induced DNA damage in mouse liver.

Alkylating Agents↗

PubMed2005

Towards single screening tests for brucellosis.

This paper describes an indirect enzyme-linked immunosorbent assay (I-ELISA) and a fluorescence polarisation assay (FPA), each capable of detecting antibody in several species of hosts to smooth and rough members of the genus Brucella. The I-ELISA uses a mixture of smooth lipopolysaccharide (SLPS) and rough lipopolysaccharide (RLPS) as the antigen, and a recombinant protein A/G conjugated with horseradish peroxidase as the detection reagent. When using individually determined cutoff values, the SLPS/RLPS combined-antigen I-ELISA detected antibody in slightly more animals exposed to SLPS or to RLPS than did I-ELISA procedures using each individual antigen separately. Similarly, the assay using combined antigens detected antibody in slightly fewer animals not exposed to Brucella sp. When a universal cutoff of 10% positivity was used (relative to strongly positive control sera of each species), the overall performance index (percentage sensitivity plus percentage specificity) value decreased by 1.0 (from 199.4 to 198.4). In the FPA, it was not possible to use a universal cutoff without significant loss of performance. The overall sensitivity value for the FPA using the combined FPA antigen was 1.0% lower than using the O-polysaccharide (OPS) from SLPS and 9.1% higher than using the core antigen (CORE) from RLPS. When the combined antigen was used, the FPA specificity was slightly higher (1.2%) than from only the OPS, and considerably higher (12.6%) than the CORE. Overall, both the I-ELISA and the FPA with combined antigens were suitable as screening tests for all species of Brucella in the animal species tested.

Animal Diseases↗

PubMed2001

Vitamin A and all-trans and 9-cis retinoic acids inhibit cell proliferation during the progression phase of hepatocarcinogenesis in Wistar rats.

The effects of vitamin A and all-trans and 9-cis retinoic acids on the progression phase of hepatocarcinogenesis were evaluated in this study. For this purpose, male Wistar rats were first submitted to the resistant hepatocyte model of carcinogenesis (diethylnitrosamine for initiation and 2-acetylaminofluorene for selection/promotion). Ten months after initiation, the animals were distributed into four groups and treated by gavage, every other day and during eight weeks, with corn oil (control group), vitamin A (10 mg/kg of body wt), all-trans retinoic acid (10 mg/kg body wt), or 9-cis retinoic acid (10 mg/kg body wt). After this period, the animals were killed one hour after intraperitoneal administration of 5-bromo-2-deoxyuridine (BrdU, 100 mg/kg body wt). At the time of sacrifice, liver samples were collected for histopathological (hematoxylin-eosin) examination and immunohistochemical detection of glutathione S-transferase and BrdU, as well as for analysis of retinol and retinoic acid concentrations. Histopathological examination showed the lowest incidence of hepatocarcinomas in vitamin A-treated animals. Moreover, groups treated with retinoids demonstrated lower hepatic BrdU labeling indexes in the neoplastic lesions, as well as in their respective surrounding tissues, than controls. Thus vitamin A and all-trans and 9-cis retinoic acid strongly inhibited cell proliferation when administered during the progression phase of hepatocarcinogenesis. Therefore, the anticarcinogenic effects that have been attributed to these retinoids could be partially related to their capacity of inhibiting in vivo cell proliferation.

2-Acetylaminofluorene↗

PubMed1998

Beta-carotene reduces the ductular (oval) cell reaction in the liver of Wistar rats submitted to the resistant hepatocyte model of carcinogenesis.

The morphology of livers of Wistar rats treated with beta-carotene (BC), vitamin A (VA, retinol acetate) or corn oil (CO, controls) and submitted to the resistant hepatocyte model of carcinogenesis was studied. Preneoplastic lesions (PNL) were smaller and less numerous in the BC group. The latter group also presented fewer placental glutathione-S-transferase (GST-P) positive and hematoxylin and eosin (H&E) distinguishable PNL, with smaller mean areas and smaller mean areas of the liver occupied by PNL. Clear cell foci predominated in BC livers. In picrosirius-stained liver sections, fibrosis, whether or not accompanying the bile ductular cells, surrounded only 16.67% of PNL in the BC group, as compared to 35.71% in the VA group and 87.72% in the CO group. Moreover, the ductular cell reaction was smaller in the BC group. Smooth muscle actin-positive cells surrounded some PNL, mostly in CO rats, and less frequently in the VA and BC groups. Examination by transmission electron microscopy (TEM) showed that cells with nuclei similar to those of perisinusoidal cells, devoid of cytoplasmic fat globules, probably represented myofibroblasts derived from Ito cells and accompanied the ductular cell reaction. On the basis of these results, we suggest that BC reduced not only the PNL but also the ductular (oval) cell reaction in this experimental model.

2-Acetylaminofluorene↗

PubMed1997

beta-carotene inhibits persistent and stimulates remodeling gamma GT-positive preneoplastic lesions during early promotion of hepatocarcinogenesis.

The inhibitory effects of beta-carotene or vitamin A on preneoplastic lesions induced in rats were compared, when specifically administered during early promotion of hepatocarcinogenesis. Initiation was performed by diethylnitrosamine. During the selection/promotion period 2-acetylaminofluorene was administered, and a partial hepatectomy was performed. Afterwards, the rats were divided into 3 groups. To two groups, beta-carotene or vitamin A were given for five weeks. Another group served as control and received corn oil. At the end of the study, beta-carotene reduced the incidence and total number of hepatocyte nodules. Vitamin A rats exhibited a lower number of nodules, but the incidence was 100%. Moreover, beta-carotene reduced the total number of gamma GT-positive preneoplastic lesions, as well as the morphometric parameters of persistent gamma GT-positive lesions. In contrast, morphometric parameters of persistent lesions remained almost unaffected in vitamin A animals. Furthermore, beta-carotene significantly increased the number of remodeling gamma GT-positive preneoplastic lesions. Vitamin A administration, however, resulted only in a small increase in the number of remodeling lesions. These results suggest that the inhibitory effects of beta-carotene during early promotion of hepatocarcinogenesis can be attributed not only to an inhibitory effect on persistent lesions, but also to a striking stimulatory activity on remodeling gamma GT-positive lesions.

Animals↗

PubMed1995

Effect of beta-carotene on the expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase in rat liver.

3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase), is a rate-limiting enzyme in the biosynthesis of not only cholesterol but also a variety of non-sterol isoprenoids. It is subjected to multivalent feedback suppression by transcriptional and post-transcriptional control mechanisms mediated by sterols and non-sterol substances. In the present study, the effect of a plant isoprenoid, beta-carotene, on the expression of HMG-CoA reductase in rat liver was investigated. In control rats the hepatic levels of mRNA transcripts of HMG-CoA reductase increased following 2/3 partial hepatectomy with two peaks, one at 8 h and the other at 24 h. Administration of the carotenoid (70 mg/kg, given every alternate day for 3 consecutive weeks) partially inhibited the increase in the transcript level with a 50% reduction at 8 h and 30% reduction at 24 h post partial hepatectomy. Nuclear run-off assays with nuclei isolated from the resting liver and from livers of control rats and rats exposed to beta-carotene for 3 consecutive weeks and killed 8 h after partial hepatectomy indicated that beta-carotene did not inhibit the rate of transcription of HMG-CoA reductase gene. These observations suggest that beta-carotene regulates the expression of HMG-CoA reductase by some post-transcriptional mechanisms.

Animals↗

PubMed1995

A comparison of beta-carotene and vitamin A effects on a hepatocarcinogenesis model.

The effects of beta-carotene (beta C) or vitamin A (VA) administration for 8 consecutive weeks were compared in male Wistar rats submitted to the resistant hepatocyte model (RH model) of hepatocarcinogenesis. Animals treated with corn oil (CO), instead of carotenoid or retinoid, served as controls. At the end of the study, beta C treatment resulted in a substantial reduction in the hepatocyte nodule incidence, total number of nodules and in the nodule multiplicity, as well as in the number and size of hepatic gamma-glutamyltranspeptidase (gamma GT)-positive foci. In contrast, animals administered with VA presented a 100% nodule incidence and only a moderate decrease in the total number of hepatocyte nodules. These showed to be in the great majority larger than nodules observed after beta C treatment. Moreover, VA administration resulted in similar number and size of gamma GT-positive foci than controls. In addition, the hepatic concentrations of total VA increased in both, beta C and VA treated animals. However, as expected, increases in the hepatic carotenoid concentrations could be only observed after beta C application. Therefore, changes in the hepatic levels of beta C, and not of VA, resulted in appreciable inhibitory effects on preneoplastic lesions of the liver. The evidence implies that the chemopreventive property of beta C is unrelated to its provitamin A activity.

Animals↗

PubMed1991

Inhibitory effects of beta-carotene on preneoplastic lesions induced in Wistar rats by the resistant hepatocyte model.

The inhibitory effects of beta-carotene (BC) on preneoplastic lesions induced in male Wistar rats by the resistant hepatocyte model was investigated. Rats were divided into six groups. Initiation was performed in all animals by a single injection of diethylnitrosamine. During the selection/promotion period five doses of 2-acetylaminofluorene were administered to the rats and a partial hepatectomy was performed. To three different groups BC was given by gavage throughout the experiment, before the initiation or during the selection/promotion period respectively. Three other groups served as controls and received corn oil instead of the carotenoid. At the end of the study (8 weeks), BC administration throughout the experiment reduced the incidence (P less than 0.005), multiplicity as well as the total number and size of hepatocyte nodules. Furthermore, it significantly decreased the number of foci per cm2 (P less than 0.05), the average focal area (P less than 0.01) and the percentage of liver parenchyma occupied (P less than 0.01). Similar results were observed when BC was given only before the initiation. However, the administration of the carotenoid during the selection/promotion period did not result in significant decreases of these parameters. These results suggest that the inhibitory effects of BC are primarily exerted on the initiation phase of the hepatocarcinogenic process. Nevertheless, continuous long-term exposure to the carotenoid would confer a greater degree of protection. In addition, by means of an analysis of correlation a positive relationship was found between the number of hepatocyte nodules and the hepatic concentration of BC. In contrast, an inverse relationship was observed between the number of nodules and the hepatic concentration of total vitamin A.

Animals↗

PubMed1991

Plasma amino acid patterns in alcoholic pellagra patients.

Plasma amino acid concentrations in 33 male alcoholic patients with pellagra (age 20-68 years) were compared with those in 17 healthy male subjects (age 20-45 years). Pellagra diagnosis was made on the basis of the typical clinical skin picture, and low urinary excretion of N'methylnicotinamide and N'methyl-2-pyridone-5-carboxamide (reduced by 70 and 80%, respectively, compared with controls). There were significant differences in body mass index, creatinine/high index and serum albumin between the two groups, indicating that besides pellagra the alcoholic patients had some degree of malnutrition. Of 17 plasma amino acids measured, the following had significantly lower concentrations in the pellagrins: tryptophan (3.65 vs 5.93 mumol/dl, pellagrin vs control), isoleucine (6.31 vs 11.13), leucine (11.54 vs 24.19), lysine (16.25 vs 34.47), methionine (2.61 vs 4.22), phenylalanine (5.71 vs 9.23), threonine (13.29 vs 26.81), valine (17.60 vs 41.06), alanine (42.54 vs 70.87), arginine (5.87 vs 10.09), tyrosine (5.57 vs 9.30). Glutamic acid was significantly higher in the pellagrins (18.45 vs 9.49). There was no difference between the groups of aspartic acid, glycine, histidine, proline and serine concentrations. It is concluded that pellagra is an important factor influencing the amino acid profiles in these patients. This finding should be taken into account when using plasma amino acid levels to assess the clinical status of the pellagrin.

Alcoholism↗

PubMed1989

Interaction of niacin and zinc metabolism in patients with alcoholic pellagra.

The effect of zinc supplementation on the metabolism of tryptophan conversion to niacin was studied in 14 alcoholic patients with pellagra and in 7 male control subjects aged 21-45 y. The pellagrins received chemically defined diets based on crystalline amino acids through an enteral tube for 7 d. Patients were divided into two groups (A and B), both receiving a diet from which tryptophan, Zn, and niacin were excluded. Patients in group B, however, received 220 mg Zn sulfate orally. Upon admission the pellagra patients had low plasma Zn levels and low urinary excretion values of N'methylnicotinamide (N'MN) and N'methyl-2-pyridone-5-carboxamide (2-PYR) in relation to the control subjects (p less than 0.01). During the experimental period there was an increase in plasma Zn levels (p less than 0.005) and in urinary N'MN (p less than 0.05) and 2-PYR (p less than 0.05) excretion in the patients receiving Zn supplementation (group B). These results suggest that Zn interacts with niacin metabolism in alcoholic patients with pellagra through a probable mediation by vitamin B-6.

Adult↗