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Biomedical subjects

A Gil

Publications and source records attributed to A Gil.

At least 181 records · Page 10Linked to original sources
PubMed1996

Interference assessment of yellow fever vaccine with the immune response to a single-dose inactivated hepatitis A vaccine (1440 EL.U.). A controlled study in adults.

The objective of this open, controlled clinical trial was to assess whether Yellow Fever (YF) vaccine would interfere with one single dose of an inactivated hepatitis A (HAV) vaccine 1440 El.U. when they are administered simultaneously. One hundred and ten healthy adults (24 +/- 4 years old, 65% females) were included and randomized to receive one single dose of HAV vaccine (Group 1) or HAV vaccine plus YF vaccine (Group 2). All subjects received a booster dose of HAV vaccine (month 6). Anti-HAV antibodies were measured (ELISA method) at screening and at months 1, 6 and 7. One month after the first inoculation, the seroconversion rates and geometric mean titers for anti-HAV were 98% and 275 mIU ml-1 in Group 1 and 100% and 239 mIU ml-1 in Group 2. After the booster dose all vaccinees had become seropositive. Administration of YF vaccine did not alter the safety profile of HAV vaccine. These results indicate that simultaneous administration of YF vaccine does not interfere with the immune response to HAV vaccine (1440 El.U.) in young healthy adults.

Adolescent↗
PubMed1996

The prevalence of anthelmintic resistance in nematode parasites of sheep in southern Latin America: Uruguay.

This survey was conducted on 252 farms randomly distributed over all the sheep raising areas in Uruguay. The study involved farms with more than 600 sheep, which represented 80% of the total sheep population of the country. Three anthelmintic groups were assessed, namely, benzimidazoles, levamisole and avermectins. Overall, the results showed 80% of sheep flocks had benzimidazole resistance, 71% had resistance to levamisole, and 1.2% of flocks showed resistance to avermectins. Approximately 28% of farms had resistance to one anthelmintic group, 64% to two anthelmintic groups, and 1% resistance to all three groups. Only 7.5% of farms had no detectable levels of anthelmintic resistance. More than 80% of farms had Trichostrongylus populations resistant to both benzimidazoles and levamisole. Resistance was recorded in all three anthelmintic groups for Haemonchus and resistance also occurred to benzimidazoles and levamisole in Ostertagia.

Agriculture↗
PubMed1996

Changes in plasma lipoproteins and liver lipids in neonatal rats.

Transient increases in triglycerides and cholesterol were found in rat liver immediately after birth. Plasma VLDL and HDL increased after birth and reached a plateau after one week of life. The content of cholesterol ester was low at birth in all lipoproteins and increased in LDL and HDL during the first week of life. After birth, VLDL became enriched in apolipoproteins C and E, whereas HDL was enriched in apolipoprotein C and depressed in apolipoprotein E. The developmental changes in plasma lipoprotein levels and compositions in rats during the first week of life are comparable to those described in humans.

Animals↗
PubMed1996

Modulation of antibody-forming cell and mitogen-driven lymphoproliferative responses by dietary nucleotides in mice.

Several studies have demonstrated that dietary nucleotides play a role in maintaining T-cell dependent immunity. In this work, we investigated the effects of nucleotide supplementation of a nucleotide-free diet (NFD) on some immunity parameters in BALB/c mice. Twenty day old mice were maintained on diets for 30 days prior to use in experiments. The addition of nucleotide mixtures to NFD resulted in an increase in the response of hemolytic IgG-forming cells induced by previous immunization with sheep erythrocytes. When NFD was supplemented with single nucleotides, AMP, GMP, or UMP increased the IgG response, whereas CMP and IMP were without effect. GMP was the only nucleotide that increased the hemolytic IgM-forming cell response. Neither the contact hypersensitivity response to dinitrofluorobenzene nor the time of death after transplantation of a syngenic lymphoma was modified by nucleotide addition to NFD. The in vitro proliferative response of splenocytes to LPS was not affected by nucleotide supplementation of NFD, but the ConA-driven proliferative response was increased in mice fed NFD supplemented with nucleotide mixtures or with UMP. These data show that dietary mononucleotides stimulated at least some T-cell dependent immunity mechanisms. Moreover, these stimulatory effects may be obtained by supplementing a nucleotide-free diet with a mixture in which mononucleotides are at the same levels as in murine breast milk.

Animals↗
PubMed1996

Deprivation of dietary nucleotides decreases protein synthesis in the liver and small intestine in rats.

BACKGROUND & AIMS: Dietary nucleotides are reported to influence the growth and functioning of the liver and small intestine. The aim of this study was to examine the mechanism by which nucleotides exert their effects in these tissues by assessing protein synthesis activity and related parameters in the presence or absence of dietary nucleotides. METHODS: Rats were fed a purified diet with or without nucleotides for 10 days. Fractional protein synthesis rate, RNA and DNA concentrations, polysome size distribution, and number of ribosomes were assessed. RESULTS: Fractional protein synthesis rates of the liver and small intestine were lower in the nucleotide-deprived group than in the control group. In the liver, RNA concentration was also lower in the nucleotide-deprived group, but values in the small intestine were similar in the two groups. In the liver, deprivation of nucleotides resulted in a reduction in the number of ribosomes and in polysome breakdown. Protein and DNA concentrations did not vary in the liver; however, the concentration of DNA was lower in the small intestine of the nucleotide-deprived group than in the control group. CONCLUSIONS: Dietary nucleotides can modulate protein synthesis in the liver and small intestine as a result of tissue-specific nucleic acid changes.

Animals↗
PubMed1996

Morphological changes in hepatocytes of rats deprived of dietary nucleotides.

The aim of the present study was to investigate the influence of dietary nucleotides on liver morphology. Adult rats were fed for 21 d on a nucleotide-containing diet or the same diet free of nucleotides. Liver sections were examined by light and transmission electron microscopy, as well as for nucleic acid and protein contents. Morphometric analysis was performed for different variables. Deprivation of dietary nucleotides resulted in a reduction in hepatocyte nuclear and nucleolar areas as well as in nuclear chromatin condensation. In addition, the rough endoplasmic reticulum was reduced, as were ribosome association and abundance, whereas fat accumulated. These findings portray dietary nucleotides as required nutrients for the liver under normal physiological conditions and suggest that an inadequate supply of nucleotides for a certain period of time has transient negative effects on liver ultrastructure and function.

Animals↗
PubMed1996

Safety, immunogenicity, and protective efficacy of one and three doses of the tetravalent rhesus rotavirus vaccine in infants in Lima, Peru.

An oral rhesus-human rotavirus tetravalent (RRV-TV) vaccine (10(4) pfu of rhesus rotavirus [type G3] and of 3 human-rhesus reassortants [G1, G2, and G4]) was evaluated in a field trial in Lima, Peru. At 2, 3, and 4 months of age, infants received either a dose of RRV-TV, an initial dose of vaccine followed by a dose of placebo at 3 and 4 months, or a dose of placebo. Rotavirus-specific IgA responses were detected by ELISA in 75% of the three-dose vaccine group, 59% of the one-dose vaccine group (P = .05), and 24% of the placebo group (P < .001): 64%, 48%, and 12% of each group, respectively, had a neutralizing antibody response to at least 1 serotype. Both one and three doses of vaccine failed to induce a significant level of protection against rotavirus diarrhea; however, they did provide some protection (range, 35%-66%) against more severe rotavirus diarrhea, especially for episodes caused by type G1.

Animals↗
PubMed1996

Dietary long-chain polyunsaturated fatty acids influence tissue fatty acid composition in rats at weaning.

We studied the fatty acid composition of plasma, plasma phospholipids, erythrocyte membrane lipids, liver microsomal phospholipids and brain lipids in rats fed three different diets varying in their (n-3) and (n-6) long-chain polyunsaturated fatty acid (LCP) concentrations for 0, 2 and 4 wk after weaning. The three diets contained 10% fat; diet HO had a high-oleic acid proportion; diet FO was enriched in n-3 LCP provided by fish oil; and diet FO + BPL contained n-3 and n-6 LCP supplied by fish oil and a brain phospholipid concentrate. At 2 and 4 wk after weaning the proportions of oleic acid in all tissues, except in liver microsomes of the FO + BPL group, were significantly higher than in weanling rats. The absence of (n-3) LCP intake resulted in significantly lower levels of docosapentaenoic [20:5(n-3)] and 22:6(n-3) acids in plasma, plasma phospholipids, erythrocyte membrane lipids and liver microsomal phospholipids but not in brain lipids compared with rats at weaning. Dietary supplementation with (n-3) LCP (FO and FO + BPL groups) for 4 wk led to higher levels of 22:6(n-3) in all tissues compared with rats fed the HO fat. The proportions of 20:4(n-6) and total (n-6) LCP were significantly lower in all tissues from rats fed the FO diet than in rats at weaning and rats fed the HO diet. After 2 and 4 wk, rats fed the FO + BPL diet had significantly higher levels of 20:4(n-6) and total (n-6) LCP in plasma, plasma phospholipids, erythrocyte lipids and liver microsomal phospholipids; the brain also showed a higher content of those fatty acids after 4 wk. Our results suggest that dietary supplementation with 20:4(n-6) and 22:6(n-3) influences the concentration of 20:4-(n-6) and 22:6(n-3) in body tissues of rats after weaning.

Animals↗
PubMed1996

Dietary restriction induces biochemical and morphometric changes in the small intestine of nursing piglets.

The purpose of this study was to evaluate the biochemical and morphometric changes in the small intestine of nursing piglets caused by 60% dietary restriction, and to ascertain whether this model reproduces the intestinal alterations caused by malnutrition in human infants. Piglets subjected to dietary restriction had significantly lower levels of mucosal DNA and protein, and significantly reduced segmental disaccharidase and leucine aminopeptidase activities compared with age-matched, freely fed controls. However, greater disaccharidase-specific activities were observed in duodenum and jejunum of diet restricted piglets compared with controls. Other findings included significantly lower thickness of the mucose, villous height and width, and villous surface area, a significantly lower number of goblet cells, and significantly greater mucosal crypt depth, intraepithelial leucocyte number, and infiltrated cells per area of lamina propria. The model reproduces most of the biochemical and morphometric changes observed in the small intestine of young human infants with chronic diarrhea and malnutrition, and may be useful in further investigations of the biochemical and molecular mechanisms of intestinal alterations caused by primary malnutrition in early infancy.

Animals↗
PubMed1996

Effects of native and hydrolyzed whey protein on intestinal repair of severely starved rats at weaning.

The aim of this study was to evaluate the effect of two sources of dietary nitrogen (isolated whey protein and hydrolyzed whey protein) on the intestinal repair of malnourished rats at weaning. The malnutrition was achieved by a 3 days' starvation period. Normally fed male Wistar rats were used as controls. Intestinal repair was studied after a refeeding period of 4 days. The parameters studied included nitrogen balance, lactase, sucrase, isomaltase, and maltase activities of the jejunum; liver acetylcholinesterase and glutamate dehydrogenase activities; and the serum amino acid profile. In addition, tests of intestinal permeability to macromolecules were performed by measurement of ovalbumin and beta-lactoglobulin in serum. Both diets of led to the recovery of the severely starved rats, in terms of the values of all the parameters evaluated. The serum beta-lactoglobulin was the only exception, because its concentration was significantly lower in the normally fed animals. This study suggests that the intestinal mucosal barrier is not completely repaired, even after a 4-day refeeding period, to the point of being suitable to accept an increase in the uptake of antigens.

Acetylcholinesterase↗
PubMed1996

Influence of dietary nucleotides on liver structural recovery and hepatocyte binuclearity in cirrhosis induced by thioacetamide.

Intake of thioacetamide in drinking water causes liver cirrhosis in rats, which exhibit many changes similar to human disease. Nucleotides play an important part in major cellular functions, and recent studies suggest that dietary nucleotides may be considered 'semi-essential' nutrients in situations when an inadequate dietary supply may affect the growth of tissues with a rapid turnover rate. The aim of this study was to assess the effect of dietary nucleotides on lesions in thioacetamide-cirrhotic rats, and to calculate the proportion of mono and binucleated hepatocytes in different experimental groups. Rats were given cirrhosis by oral intake of thioacetamide in the drinking water (300 mg/l) for four months. One group was treated with a standard nucleotide free diet, and another group was treated with the same diet supplemented with 250 mg of nucleotides per 100 g of diet for one and two weeks. A striking reduction (mean (SEM)) in the proportion of binucleated cells was seen in thioacetamide-cirrhotic rats (4.8 (1.3) v 21.4 (1.0)), showing a change in the mitotic mechanism in focal lesions. Cirrhotic rats that consumed a semipurified diet supplemented with nucleotides during two weeks showed considerable histological regeneration of the injured liver. These animals had significantly higher proportion of binucleated cells than did animals at the beginning of the recovery period (8.2 (1.2) v 4.8 (1.3)). In the second week of recovery, both types of diet (F = 5.54, p < 0.05) and the previous administration of thioacetamide (F = 142.82, p < 0.001) had significant effects on the percentage of binucleated hepatocytes.

Animals↗
PubMed1996

Comparison of content and distribution of human milk gangliosides from Spanish and Panamanian mothers.

The lactational changes in content and distribution of gangliosides in human milk from Spanish and Panamanian mothers delivering term newborns were studied. There were no statistically significant differences in the concentration of gangliosides between Spanish and Panamanian milk. The ganglioside content expressed as a function of total milk lipids tended to decrease as lactation progressed in both types of milk. There was a significant correlation (r = 0.5896; p = 0.0062) between ganglioside and total lipid contents in Panamanian milk. However, in Spanish milk, the correlation was not significant (r = 0.1516; p = 0.3439). We did not detect important differences in the relative concentrations of individual gangliosides during lactation among milk samples from Spanish and Panamanian mothers. For both of them, GD3 was the most abundant ganglioside in colostrum, whilst in mature milk it was GM3.

Adult↗
PubMed1996

Age-related response of the small intestine to severe starvation and refeeding in rats.

The impact of severe starvation and refeeding on the intestinal mucosa of rats of different ages has been studied in a diet-controlled model. Structural and functional alterations of the small intestinal mucosa were assessed by standard parameters including mucosal protein, DNA content as well as maltase, sucrase and leucine aminopeptidase enzymatic activities. Decreases in mucosal mass, DNA, protein and leucine aminopeptidase activity in both the jejunum and ileum caused by starvation, diminished with age. The depression of disaccharidase activities increased with age in the jejunum but not in the ileum. Except for jejunal protein and leucine aminopeptidase activity, the recovery from starvation, after refeeding, was complete for the other parameters studied, regardless of age.

Aging↗
PubMed1996

Monoclonal gammopathy associated with crescentic glomerulonephritis and antimyeloperoxidase antibodies.

A 68-year-old male patient suffering from dizziness, gait instability, deafness, and visual loss showed proteinuria, hematuria, reduced creatinine clearance, and a monoclonal IgA lambda component. Renal biopsy revealed crescentic glomerulonephritis. Serum antibodies against myeloperoxidase were identified. These antibodies were IgG, not related to the IgA monoclonal component. This clinical description adds new information to the spectrum of diseases associated with glomerulonephritis and antimyeloperoxidase antibodies and illustrates that a monoclonal component cannot be directly implicated in the pathogenesis of a vasculitic process associated with antineutrophil cytoplasm antibodies.

Aged↗
PubMed1996

Determination of pantothenic acid in infant milk formulas by high performance liquid chromatography.

A reverse-phase liquid chromatographic method was adapted for the assay of pantothenic acid in infant milk formulas. Sample preparation consisted of deproteination with acetic acid and sodium acetate solutions, followed by centrifugation and filtration. The chromatographic system included a C-18 column and a mobile phase consisting of a sodium phosphate buffer and acetonitrile (97:3, vol/vol). The column effluent was monitored by UV detection at 197 nm. The system was linear from 50 to 800 ng. The recoveries of pantothenic acid from augmented samples ranged from 89 to 98%, and the coefficients of variation ranged from 1.17 to 3.20%. The results obtained with the HPLC and a microbiological method were highly correlated for starting infant formula, follow-up infant formula, and formula for infants of low birth weight from four different manufactures. All formulas analyzed contained pantothenic acid at concentrations higher than those declared on their nutritional labels and were in compliance with international recommendations.

Chromatography, High Pressure Liquid↗
PubMed1996

Autosomal folate sensitive fragile sites in an autistic Basque sample.

The autosomal folate-sensitive fragile sites (FS) expression has been analyzed in an autistic children sample and in a control sample. The results obtained have proved that there is a higher frequency of expression of fragile sites in autistic children than in the control sample. The differences are statistically significant. The sex differences level is similar in both groups in relation to fragile sites expression. Three rare fragile sites, 2q13, 6p23, 12q13, are only expressed in autistic individuals. The meaning of these results have been discussed.

Adolescent↗