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Biomedical subjects

A Gil

Publications and source records attributed to A Gil.

At least 145 records · Page 8Linked to original sources
PubMed1998

Prevalence of antibodies against varicella zoster, herpes simplex (types 1 and 2), hepatitis B and hepatitis A viruses among Spanish adolescents.

The aim of this cross-sectional study was to assess the seroprevalence of antibodies against varicella zoster (VZV), herpes simplex type 1 (HSV-1) and type 2 (HSV-2), hepatitis B (HBV) and hepatitis A (HAV) viruses in adolescents (14-17 years of age) in Madrid, Spain. At the study visit, demographic data and blood samples were obtained. The enzyme linked immunosorbent assay (ELISA) method was used to assess the presence of anti-VZV, anti-HSV-1, anti-HSV-2, anti-HBc and anti-HAV antibodies. A total of 1191 serum samples were collected. Mean age (SD) and male/female ratio of the study population were 15.3 (1.1) years and 0.9, respectively. Seroprevalences obtained were as follows: anti-VZV (94%), anti-HSV-1 (46%), anti-HSV-2 (5%), anti-HBc (3%) and anti-HAV (5%). These data show that Spanish adolescents should be considered a target group for prevention programmes against HSV-2, HBV and HAV infections.

Adolescent↗
PubMed1998

Dietary nucleotides correct plasma and liver microsomal fatty acid alterations in rats with liver cirrhosis induced by oral intake of thioacetamide.

BACKGROUND/AIMS: Dietary nucleotides modulate a number of metabolic processes, including long-chain polyunsaturated fatty acid metabolism. In this study, we evaluated the effect of dietary nucleotides on plasma and liver microsomal fatty acid profiles in a rat model of liver cirrhosis induced by oral intake of thioacetamide. METHODS: Fifty-four female Wistar rats were assigned to one of the following groups: rats in the thioacetamide group (n=45) were given 300 mg thioacetamide/l in their drinking water for 4 months, and rats in the control group (n=9) received water during the same period. After 4 months of treatment, 9 rats in each group were killed. The remaining rats in the thioacetamide group were divided into two new groups, and the animals in each were allowed to recover for 1 or 2 weeks on either a nucleotide-free diet or the same diet supplemented with 50 mg of each of the following: AMP, GMP, CMP, IMP and UMP per 100 g diet. RESULTS: Saturated (mainly stearic acid), monounsaturated, and n-6 long-chain polyunsaturated fatty acids (mainly arachidonic acid), and also the unsaturation index decreased in plasma of rats with experimental cirrhosis. Administration of the diet supplemented with nucleotides to thioacetamide-treated rats corrected plasma levels of saturated, n-6 long-chain polyunsaturated fatty acids and the unsaturation index. In liver microsomes, the cirrhotic rats showed lower levels of protein and higher levels of palmitic, oleic, linoleic and arachidonic acids. Protein concentrations and levels of all the above-mentioned fatty acids were corrected with the nucleotide-enriched diet. CONCLUSIONS: Dietary nucleotides contribute to correcting plasma and liver microsomal fatty acid alterations in rats with liver cirrhosis induced by chronic oral administration of thioacetamide.

Administration, Oral↗
PubMed1998

Preferential localization of exocytotic active zones in the terminals of neurite-emitting chromaffin cells.

Amperometry using 2.5 microm radius carbon fiber electrodes was employed to study exocytotic catecholamine release from individual cultured bovine chromaffin cells. The secretory responses to either direct depolarization or nicotinic receptor stimulation were focal in nature in both round and neurite-emitting cells. In contrast to the random distribution of active sites found in round cells, bipolar and tripolar chromaffin cells had responsive zones preferentially located at neurite terminals as indicated by the lower probability of finding "silent" electrode positions and an increased nicotinic-receptor responsiveness when compared with the cell body. In agreement with these data we have observed a preferential deposition of dopamine-beta-hydroxylase into the neurite terminal plasmalemma after stimulation of intact cells. These observations might be of interest since the differences in the distribution of secretory "spots" between round and neurite-emitting chromaffin cells could be used to study the molecular factors determining active site localization.

Acetylcholine↗
PubMed1998

Plasma and red blood cell fatty acid composition in small for gestational age term infants fed human milk or formula.

The purpose of the present study was to evaluate the effects of feeding human milk or milk formula on the fatty acid composition of plasma and red blood cell (RBC) lipids in at term small for gestational age infants (SGA) for the first 3 months of life. One group of infants received a formula with a linoleic:alpha-linolenic acid ratio of 10:1 (MF group). Another group served as control and received their own mother's milk (HM group). Blood samples were taken at birth and at 1 week, 4 weeks, and 3 months of life. Plasma and RBC fatty acid composition were analyzed by gas liquid chromatography and results of total plasma lipids were expressed as concentrations by adding an internal standard. Concentrations of saturated and monounsaturated fatty acids increased in total plasma lipids with age in all infants. In contrast, those fatty acids decreased when results were expressed as percentages of total fatty acids. Long-chain polyunsaturated fatty acids (LCP) decreased regardless of how results were expressed, but the absolute concentrations of these fatty acids in plasma available for tissue accretion were greater than suggested by the percentage results. Plasma and RBC docosahexaenoic acid (22:6n-3) decreased in the MF group in comparison to the HM group. Arachidonic acid (20:4n-6) was lower in plasma of MF-fed infant but not in RBC phospholipids. We conclude that term SGA infants fed an adapted milk formula with a linoleic:alpha-linolenic acid ratio of 10:1 but devoid of LCP may lead to a low n-3 LCP status.

Erythrocytes↗
PubMed1998

Special formulas in infant nutrition: a review.

Special formulas should only be used by medical prescription and for those lactating infants with diagnosed nutritional problems. Lactose-free formulas or those based on soy are the logical choice when the exclusion of lactose from the diet is considered necessary. At present, there is no concensus on the appropriateness of soy formulas for the treatment and prevention of nutritional allergies and current opinion seems to favour hydrolyzed protein formulas. High-degree protein hydrolysate formulas are used to treat lactating infants with an allergy to cow milk proteins or with serious nutritional problems. These formulas are not without risk, as they may contain residual epitopes capable of provoking a severe allergic reaction. Before using these formulas, allergenicity tests should be performed, particularly for highly sensitive infants. The unpleasant taste and high cost of these formulas, in addition to possible nutritional problems, limit their use in the prevention of atopic disease, although their efficacy is well established. Partially protein hydrolysate formulas are only used for preventive purposes and are not suitable for lactating infants with a proven allergy to cow milk. Although these formulas can reduce the incidence or delay the appearance of certain atopic symptoms, they have not been shown to prevent IgE-mediated allergic reactions to cow's milk and so their effectiveness is open to question.

Dietary Proteins↗
PubMed1998

Neonatal dietary gangliosides.

Gangliosides are glycosphingolipids that are widely distributed in vertebrate tissues and body fluids and which are specially abundant in neural tissues. Milk from different species has a particular ganglioside content and profile. Human milk has a higher content of gangliosides than bovine milk. GD3 and GM3 are the predominant individual gangliosides in bovine milk. In human colostrum GD3 is also the main ganglioside whereas in human mature milk GM3 predominates over the other gangliosides. Human milk also contains GM1 and a number of highly polar gangliosides, which may play an important role in infant physiology. GM1 has been shown to inhibit Escherichia coli and Vibrio cholerae enterotoxins. We have found that a ganglioside-supplemented infant formula modifies the intestinal ecology of preterm newborns, increasing the Bifidobacteria content and lowering that of Escherichia coli. Although the exact mechanism by which dietary gangliosides reduce the fecal content of Escherichia coli is unknown, in vitro experiments suggest that they may act as false intestinal receptors for some strains of this bacteria. Since GD3 and other gangliosides have been involved in mechanisms of lymphocyte activation and differentiation, dietary gangliosides might have a function in intestinal immunity development.

Animals↗
PubMed1998

Bone mineralization status measured by dual energy radiographic densitometry in preterm infants fed commercial formulas.

We have studied the effect of two preterm commercial infant formulas with different calcium and phosphorus contents on the mineral balance and bone mineralization of 30 preterm infants at 1 month of age. Bone mineralization was measured by dual energy X-ray densitometry. The formula supplying a higher content of calcium and phosphorus promoted higher mineral retention (P<0.01) as well as higher bone mineral content (1.556 vs. 1.073 g, P<0.01) and bone mineral density (0.458 vs. 0.424 g/cm2, P<0.05), approaching values of the control group, which comprised a cohort of 15 preterm newborns whose gestational age was 4 weeks older than the subjects selected to be fed with the formulas. The intake of calcium correlated with retention (r=0.69); the phosphorus intake also correlated with phosphorus retention (r=0.95). Intakes of calcium and phosphorus correlated with the bone mineral content (r=0.65) and with bone mineral density (r=0.49). We conclude that formulas for preterm infants should not have a calcium content lower than 120 mg/100 kcal and should have a calcium/phosphorus ratio of about 2 to promote adequate bone mineralization.

Absorptiometry, Photon↗
PubMed1998

Changes in plasma and colonic mucosa fatty acid profiles in rats with ulcerative colitis induced by trinitrobenzene sulfonic acid.

Polyunsaturated fatty acids have a key role in the pathogenesis of inflammatory bowel disease since some of the arachidonic acid-derived eicosanoids have been found to be increased in inflamed intestinal mucosa in the acute phase of human disease. The aim of this study was to prospectively assess plasma and colon mucosa fatty acid patterns in rats with experimental ulcerative colitis. Twenty rats were treated with trinitrobenzene sulfonic acid and 20 with NaCl; two groups were killed after one week and two after two weeks to evaluate colon damage. Plasma was obtained by aortic puncture and colonic mucosa was scraped off and the fatty acid pattern was determined by gas-liquid chromatography. Total, saturated, and monounsaturated plasma fatty acids were significantly higher in both periods of ulcerative colitis as compared to controls. Plasma n-6 fatty acids were increased after treatment, but no significant changes were observed concerning to n-3 fatty acids. With regard to colon mucosa, saturated and monounsaturated fatty acids did not change because of the disease; however, n-6 fatty acids decreased in the first week and increased in the second week and n-3 fatty acids were increased. Changes on the fatty acid distribution in plasma did not parallel to those of colonic mucosa except for 22:6(n-3). We have also found that experimental ulcerative colitis induced by trinitrobenzene sulfonic acid reproduces many of the features related to changes in plasma and colon mucosa fatty acids observed in the human disease.

Animals↗
PubMed1998

Dietary monounsaturated n-3 and n-6 long-chain polyunsaturated fatty acids affect cellular antioxidant defense system in rats with experimental ulcerative colitis induced by trinitrobenzene sulfonic acid.

The intrarectal administration of trinitrobenzene sulfonic acid in rats induces ulcerative colitis, which results in histological alterations of colonic mucosa, severe modification of the cellular antioxidant defense system, and enhanced production of inflammatory eicosanoids. This study evaluated the influence of different dietary fatty acids, i.e., monounsaturated, n-3, and n-3 + n-6 polyunsaturated fatty acids, on the recovery of the colonic mucosa histological pattern, the cellular antioxidant defense system of colon, and PGE2 and LTB4 colonic mucosa contents in a model of ulcerative colitis induced by intrarectal administration of trinitrobenzene sulfonic acid. Administration of dietary n-3 polyunsaturated fatty acids led to a minimum stenosis score, a higher histological recovery, lower colon alkaline phosphatase and gamma-glutamyltranspeptidase activities, and lower mucosal levels of PGE2 and LTB4 compared with the other two experimental groups. However, glutathione transferase, glutathione reductase, glutathione peroxidase, and catalase activities were lower in the group treated with n-3 polyunsaturated fatty acids than in the groups fed with either the monounsaturated or the n-6 + n-3 polyunsaturated enriched diet. We conclude that n-3 polyunsaturated fatty acids can be administered to prevent inflammation in ulcerative colitis, but they cause a decrease in the colonic antioxidant defense system, promoting oxidative injury at the site of inflammation.

Animals↗
PubMed1998

Abnormalities in plasma and red blood cell fatty acid profiles of patients with colorectal cancer.

We evaluated total plasma fatty acid concentrations and percentages, and the fatty acid profiles for the different plasma lipid fractions and red blood cell lipids, in 17 patients with untreated colorectal cancer and 12 age-matched controls with no malignant diseases, from the same geographical area. Cancer patients had significantly lower total plasma concentrations of saturated, monounsaturated and essential fatty acids and their polyunsaturated derivatives than healthy controls; when the values were expressed as relative percentages, cancer patients had significantly higher proportions of oleic acid and lower levels of linoleic acid than controls. With regard to lipid fractions, cancer patients had higher proportions of oleic acid in plasma phospholipids, triglycerides and cholesterol esters, and lower percentages of linoleic acid and its derivatives. On the other hand, alpha-linolenic acid was significantly lower in triglycerides from cancer patients and tended to be lower in phospholipids. Its derivatives also tended to be lower in phospholipids and triglycerides from cancer patients. Our findings suggest that colorectal cancer patients present abnormalities in plasma and red blood cell fatty acid profiles characterized by lower amounts of most saturated, monounsaturated and essential fatty acids and their polyunsaturated derivatives, especially members of the n-6 series, than their healthy age-matched counterparts. These changes are probably due to metabolic changes caused by the illness per se but not to malnutrition.

Adult↗
PubMed1998

Decreased excretion of nitrate and nitrite in essential hypertensives with renal vasoconstriction.

Most hypertensive patients exhibit increased renal vascular resistance (RVR). This study was designed to investigate whether there exists any relationship between RVR and the production of nitric oxide (NO) in patients with essential hypertension. The study was performed in 49 non-treated patients with mild-to-moderate essential hypertension, and 20 age- and sex-matched normotensive subjects on a controlled sodium diet. Renal hemodynamics was measured in terms of the clearance of para-aminohippuric acid and inulin. Urinary excretion of nitrate and nitrite (NO3- plus NO2-) was determined as an index of NO production. As compared with normotensives, hypertensive patients exhibited higher (P < 0.001) RVR and lower (P < 0.05) urinary excretion of NO3- plus NO2-. With the 100% confidence (upper) limit of the normotensive population as a cut-off point, a subgroup of 30 hypertensives had an abnormally high RVR. The excretion of NO3- plus NO2- was lower (P < 0.005) in hypertensives with high RVR than in normotensives and the remaining hypertensives. No differences were found in the urinary excretion of NO3- plus NO2- between normotensives and hypertensives with normal RVR. Statistically significant associations were seen between diastolic blood pressure and RVR (r = 0.341, P < 0.05) and urinary excretion of NO3- plus NO2- (r = -0.387, P < 0.01) in all hypertensives. These results indicate that there is a subgroup (61%) of hypertensive patients with diminished urine levels of NO3- plus NO2- in which RVR is abnormally increased. Thus, it is suggested that in essential hypertension a diminished renal ability to produce NO by the endothelium may be involved in exaggerated renal vasoconstriction.

Endothelium, Vascular↗
PubMed1998

Dual effects of botulinum neurotoxin A on the secretory stages of chromaffin cells.

Truncation of the C-terminal domain of the synaptosomal associated protein of 25 kDa (SNAP-25) by botulinum neurotoxin A (BoNT A) has been shown to block neuroendocrine cell secretion. It is unclear, however, if toxin mechanism involved the affection of a single or more events of the exocytotic cascade. BoNT A induced changes in both the degree of inhibition and the kinetics of catecholamine secretion from populations of cultured bovine chromaffin cells. Ca2+-dependent secretion from digitonin-permeabilized cells showed partial inhibition associated with the alteration of a slow secretory phase at different toxin concentrations. In contrast, in intact cells stimulated by depolarization, cell treatment with low concentrations (1 nM) of the toxin affected the late phase of secretion, whereas 100 nM BoNT A-poisoned cells showed an alteration even of fast components. The high degree of inhibition associated with fast secretory component alteration was dependent on Ca2+ entry through the Ca2+ channels, as it was absent from cells permeated with the A23187 Ca2+ ionophore. Vesicle pools implicated in the effect of BoNT A on the secretory response from single cells were identified using amperometry. These studies supported the macroscopic view by showing that secretion from BoNT A-treated permeabilized cells presented specific inhibition of late vesicle fusions. Intact cells showed alterations in the late vesicle pool (t1/2 = 39 s) recruited during prolonged or repetitive KCI depolarizations using 1 nM BoNT A-treated cells as well as in an intermediate kinetic pool (t1/2 = 18 s) at higher toxin concentrations (100 nM). The faster resolved component (t1/2 = 8 s) or the membrane fusion event itself were not affected. Our results demonstrate that removal of the last nine C-terminal amino acids of SNAP-25 by BoNT A has a specific effect on two different and distal secretory stages in chromaffin cells.

Adrenal Glands↗
PubMed1998

Growth, development and differentiation: a functional food science approach.

Few other aspects of food supply and metabolism are of greater biological importance than the feeding of mothers during pregnancy and lactation, and of their infants and young children. Nutritional factors during early development not only have short-term effects on growth, body composition and body functions but also exert long-term effects on health, disease and mortality risks in adulthood, as well as development of neural functions and behaviour, a phenomenon called 'metabolic programming'. The interaction of nutrients and gene expression may form the basis of many of these programming effects and needs to be investigated in more detail. The relation between availability of food ingredients and cell and tissue differentiation and its possible uses for promoting health and development requires further exploration. The course of pregnancy, childbirth and lactation as well as human milk composition and the short- and long-term outcome of the child are influenced by the intake of foods and particularly micronutrients, e.g. polyunsaturated fatty acids, Fe, Zn and I. Folic acid supplementation from before conception through the first weeks of pregnancy can markedly reduce the occurrence of severe embryonic malformations; other potential benefits of modulating nutrient supply on maternal and child health should be further evaluated. The evaluation of dietary effects on child growth requires epidemiological and field studies as well as evaluation of specific cell and tissue growth. Novel substrates, growth factors and conditionally essential nutrients (e.g. growth factors, amino acids, polyunsaturated fatty acids) may be potentially useful as ingredients in functional foods and need to be assessed carefully. Intestinal growth, maturation, and adaptation as well as long-term function may be influenced by food ingredients such as oligosaccharides, gangliosides, high-molecular-mass glycoproteins, bile salt-activated lipase, pre- and probiotics. There are indications for some beneficial effects of functional foods on the developing immune response, for example induced by antioxidant vitamins, trace elements, fatty acids, arginine, nucleotides, and altered antigen contents in infant foods. Peak bone mass at the end of adolescence can be increased by dietary means, which is expected to be of long-term importance for the prevention of osteoporosis at older ages. Future studies should be directed to the combined effects of Ca and other constituents of growing bone, such as P, Mg and Zn, as well as vitamins D and K, and the trace elements F and B. Pregnancy and the first postnatal months are critical time periods for the growth and development of the human nervous system, processes for which adequate substrate supplies are essential. Early diet seems to have long-term effects on sensory and cognitive abilities as well as behaviour. The potential beneficial effects of a balanced supply of nutrients such as I, Fe, Zn and polyunsaturated fatty acids should be further evaluated. Possible long-term effects of early exposure to tastes and flavours on later food choice preferences may have a major impact on public health and need to be further elucidated. The use of biotechnology and recombinant techniques may offer the opportunity to include various bioactive substances in special dietary products, such as human milk proteins, peptides, growth factors, which may have beneficial physiological effects, particularly in infancy and early childhood.

Adolescent↗
PubMed1998

Severe malnutrition alters lipid composition and fatty acid profile of small intestine in newborn piglets.

The goal of this study was to evaluate the influence of severe protein-energy malnutrition (PEM) on lipid composition and fatty acid profile in the small intestinal mucosa of lactating pigs. Malnutrition was achieved by 80% protein-energy restriction for 30 d (20% of the food intake in the control group) in 7-d-old newborn piglets. Malnourished piglets had significantly lower concentrations of cholesterol, phospholipid and triglycerides in the jejunum and ileum compared with freely fed controls. Fatty acid composition of the intestinal mucosa was severely affected by malnutrition. A sharp decline in the relative percentages of (n-3) and (n-6) long-chain polyunsaturated fatty acids (LC-PUFA) in malnourished piglets paralleled higher (n-9) fatty acid proportions in the total mucosa, microsomes and phospholipids of the jejunum. The structure of the small intestine was severely affected as assessed by light and electron microscopy, and alkaline phosphatase and disaccharidase activities in the intestinal mucosa were also significantly impaired. Plasma from malnourished piglets had significantly lower concentrations of (n-3) and (n-6) LC-PUFA than that of control piglets; however, the fatty acid composition of red blood cell membrane was unaffected. Our results suggest that early severe PEM dramatically modifies intestinal membrane lipid composition. Changes in the lipid composition of the small intestinal mucosa and in phospholipid distribution as well as in the fatty acid profile may alter membrane fluidity and organization. These alterations appear to affect the activity of membrane-bound hydrolytic enzymes.

Alkaline Phosphatase↗
PubMed1998

Gestational age and origin of human milk influence total lipid and fatty acid contents.

The human milk composition may be influenced by several factors, such as gestational age or genetic characteristics and dietary habits of different populations. To analyze the total lipid and fatty acid contents of human milk, we have conducted two studies, one on mothers who had delivered preterm and term newborns and another on mothers from two different sociocultural backgrounds (Spain and Panama). The total lipid content (g/100 g wet weight) was significantly higher in term (2.76 +/- 0.66; mean +/- SD) than in preterm mature milk (1.06 +/- 0.4). The relative amount of 18:1n-9 was significantly higher in preterm than in term milk for transitional and mature milk, whereas that for the colostrum followed the opposite trend. Concerning the comparison between milk from mothers born in different countries, the relative contents of each of the fatty acids 16:0, 16:1n-7, 18:2n-6, 18:3n-3, and 22:5n-3 were higher in Panamanian than in Spanish milk, whereas the mean percentages of saturated fatty acids < 14:0, of 16:1n-9, and of 18:1n-9 were higher in Spanish than in Panamanian milk. Statistically significant differences were found during the three periods of lactation considered for almost all the fatty acids mentioned above, especially for 18:1n-9 and 18:3n-3. Although the potential biological significance of the changes in oleic acid content between preterm and term milk remains unclear, differences in fatty acid content between Spanish and Panamanian milk reflect the different composition of the diet among women from these countries.

Cohort Studies↗
PubMed1998

Carcinoid tumor of the uterine corpus. A case report.

BACKGROUND: Carcinoid tumors are neoplasms of neuroendocrine origin that rarely affect the genital tract. CASE: A 75-year-old woman underwent hysterectomy and bilateral adnexectomy due to vaginal bleeding and uterine pathology (leiomyoma, cervical low grade squamous intraepithelial lesions and endometrial hyperplasia on ultrasound). Pathologic examination of the specimen disclosed a uterine corpus carcinoid tumor. The patient had been taking tamoxifen for adjuvant treatment of breast cancer diagnosed and treated seven years before. CONCLUSION: A review of the literature revealed one case of carcinoid tumor of the uterine wall. There does not appear to be any relationship between tamoxifen and the carcinoid tumors reported.

Aged↗
PubMed1998

[Hernia of the lumbar discs in persons at work. Results of a retrospective study in a series of 189 consecutive patients].

INTRODUCTION: Owing to recent advances in the diagnosis and treatment of lumbar disc pathology, the functional results obtained have improved, although there are still certain factors which affect this. The results in the work place are particularly problematic. OBJECTIVE: With the aim of finding an answer to the problem of relapse of the sciatica syndrome in patients operated on for hernia of the lumbar discs, we describe a study carried out in a consecutive group of patients who had had operations for hernias of lumbar discs whilst at work, within the context of revindication involved in this situation. PATIENTS AND METHODS: We describe the results obtained in a series of 189 patients who had been operated on for lumbar disc pathology. Conventional open surgery was performed in 105 cases. Percutaneous nucleotomy was done in the remainder. In 17.39%, operations were done at more than one level, making a total of 265 discs operated on. RESULTS: These were considered good when the patient returned to his former work. Good results were obtained in 72% of the patients treated by open surgery and 68% of those treated by percutaneous nucleotomy. The re-operation rate was 8.57% for open surgery and 32.14% for percutaneous nucleotomy (p < 0.05). CONCLUSIONS: The main reason for re-operation was a recurrence of disc protrusion. Good results were obtained in 80% of those reoperated. All reoperations were done using open surgery techniques. Overall assessment of the cases, including initial and re-operations, gave good results, reaching 83.59% in the current series.

Adult↗