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Biomedical subjects

E Aguirre

Publications and source records attributed to E Aguirre.

At least 19 recordsLinked to original sources
PubMed2006

Kindling increases aversion to saccharin in taste aversion learning.

Kindling is a model in which an initially subconvulsive electrical stimulation of certain brain areas eventually develops a generalized seizure that produces behavioral and long term neuronal changes. In the present study we evaluated if kindling can modify conditioning taste aversion (CTA). In this paradigm animals acquire aversion to saccharin when it is presented as the conditioned stimulus (CS) followed by an injection of lithium chloride (LiCl) that induces a gastric irritation as the unconditioned stimulus (US). Male Wistar rats were implanted with bipolar electrodes aimed at the right amygdala (AMG) or at the right insular cortex (IC). The animals were stimulated daily until they reached stages 2-4 (intermediate) or until kindling was fully established (three consecutive stage 5 seizures). At least two weeks after kindling stimulation had ceased the animals were deprived of water for 24 h and given 10-min drinking sessions twice a day for 4 days. On day 5 (morning session) tap water was replaced by saccharin solution (0.1%), 20 min later the animals were injected with LiCl (7.5 ml/kg i.p., 0.2 M) to induce gastric malaise or taste aversion. After three more days of baseline consumption, water was substituted by a fresh 0.1% saccharin solution to test the aversion. AMG-kindling delayed the extinction of CTA. Animals with kindling in the IC had a higher retention than the sham kindling group; that is, they drank significantly less saccharin solution than the other groups. The results of the present experiment show that local modification of brain function induced by kindling stimulation can prolong the aversive effects of CTA.

Amygdala↗
PubMed2006

Antibodies from patients with dengue viral infection mediate cellular cytotoxicity.

Acute and late convalescent sera (collected at day 5 of disease onset and 1 year later) from dengue fever (DF) and dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) laboratory confirmed cases, were tested for antibody-dependent cell-mediated cytotoxicity (ADCC) activity using dengue 1 (DENV-1) or dengue 2 (DENV-2) infected cells as target. All patients experienced their first dengue virus (DENV) infection 20 years before. ADCC activity was detected in acute sera from DHF/DSS but not in sera from DF patients. However, 1 year after illness, ADCC activity was observed in all cases. This preliminary report represents one of the few studies of ADCC in dengue patients and suggests that ADCC could be implicated in dengue pathogenesis.

Antibodies, Viral↗
PubMed2006

Genetic characterization of Anaplasma (Ehrlichia) platys in dogs in Spain.

This paper reports the first genetic characterization of Anaplasma (Ehrlichia) platys in Spain from a naturally infected dog. The dog presented clinical signs compatible with canine ehrlichiosis. After DNA extraction and PCR amplification, 16S rRNA gene and citrate synthase gene ( gltA) of this agent were amplified. The GenBank accession number for the nucleotide sequence of the 16S rRNA gene of this strain is AY530806. The A. platys strains registered in France and Japan showed the highest similarity to the 16S rRNA gene sequence obtained from the Spanish strain. In the amplification of the gltA gene, a 1443 bp fragment was obtained, and three nucleotide differences were detected in comparison with other strains sequences. These data confirm the presence of A. platys in a dog showing clinical signs compatible with ehrlichiosis in Spain.

Anaplasma↗
PubMed2000

Geographic differences in bone mineral density of Mexican women.

The aim of this study was to generate standard curves for normal spinal and femoral neck bone mineral density (BMD) in Mexican women using dual-energy X-ray absorptiometry (DXA), to analyze geographic differences and to compare these with 'Hispanic' reference data to determine its applicability. This was a cross-sectional study of 4460 urban, clinically normal, Mexican women, aged 20-90 years, from 10 different cities in Mexico (5 in the north, 4 in the center and 1 in the southeast) with densitometry centers. Women with suspected medical conditions or who had used drugs affecting bone metabolism, were excluded. Lumbar spine BMD was significantly higher (1.089 +/- 0.18 g/cm2) in women from the northern part of Mexico, with intermediate values in the center (1.065 +/- 0.17 g/cm2) and lower values (1.013 +/- 0.19 g/cm2) in the southeast (p < 0.0001). Similarly, femoral neck BMD was significantly higher in women from the north (0.895 +/- 0.14 g/cm2), intermediate in the center (0.864 +/- 0.14 g/cm2) and lower (0.844 +/- 0.14 g/cm ) in the southeast part of Mexico (p < 0.0001). Northern Mexican women tend to be taller and heavier than women from the center and, even more, than those from the southeast of Mexico (p < 0.0001). However, these differences in BMD remained significant after adjustment for weight (p < 0.0001). A significant loss (p < 0.0001) in BMD was observed from 40 to 69 years of age at the lumbar spine and up to the eighth decade at the femoral neck. Higher and lower lumbar spine values, as compared with the 'Hispanic' population, were observed in Mexican mestizo women from the northern and southeastern regions, respectively. In conclusion, there are geographic differences in weight and height of Mexican women, and in BMD despite adjustment for weight.

Absorptiometry, Photon↗
PubMed2000

Can a generalized kindling seizure induce a reward state?

The postictal behavioral depression (PBD), characterized by behavioral immobility and unresponsiveness to environmental stimuli, observed after a stage 5 kindling seizure is opioid dependent. Morphine injection prolongs while naloxone and naltrexone (opioid antagonists) reduce or eliminate PBD. Opioids have clear rewarding actions that can be easily detected by place preference conditioning (PPC). In the present study, we evaluated if the opioid release after a stage 5 kindling seizure that produces PBD could induce PPC. Male rats were kindled in the medial preoptic area (MPOA), the amygdala (AMG) or insular cortex (IC). After kindling was established their initial preference in a three-compartment chamber was determined. During conditioning, subjects received a standard kindling stimuli that evoked a stage 5 seizure. At the end of the after discharge and during the PBD the animals were placed in the non-preferred chamber for 30 min. On alternate days they were placed without stimulation in the preferred chamber. At the end of conditioning the kindled groups showed a clear change of preference. This change of preference was completely blocked by injection of naloxone. These results suggest that opioid release after a stage 5 kindling seizure can induce a positive affect of sufficient intensity and duration to induce conditioning.

Amygdala↗
PubMed2000

Energy requirements in Chilean infants.

AIM: To evaluate the energy requirements of breast fed infants. METHODS: The study was conducted in 17 healthy exclusively breast fed infants of normal birth weight (mean (SD) 3332 (280) g). Energy expenditure by the doubly labelled water method and milk intake by the dose to infant method were measured at 34 (4) days. A dose of 0. 2 g/kg deuterium oxide (99.8%) and 2.0 g/kg 10% (18)O labelled water was given to the infants, and urine samples were collected for seven consecutive days after dosing. RESULTS: The mean (SD) weight of the infants during the period of evaluation was 4617 (343) g and weight gain 34.0 (7.5) g/day. Daily milk intake was 728 (101) g and its metabolisable energy content 2.71 kJ/g. The energy expenditure of the infants was 1205 (312) kJ/day and energy required for growth was 607 (130) kJ/day. When combined this produced an energy requirement of 391 kJ/kg/day for these infants. CONCLUSION: These data agree with those from other studies in the United Kingdom and the United States and suggest that adequate growth can be achieved with 19.4% less energy than recommended by FAO/WHO/UNU.

Body Composition↗
PubMed1999

[Osteoporosis in Mexican postmenopausal women. Magnitude of the problem. Multicenter study].

Incidencia of osteoporosis induced fractures increases with age; risk increases exponentially as bone mass decreases. Women are prone to osteoporosis 2 to 3 times more than men, due to lower "peak" bone mass and the accelerated loss that occurs after the menopause. The prevalence of osteoporosis in with Caucasian postmenopausal women varies from 16 to 30% depending upon the number of sites measured (lumbar spine/hip and/or forearm). The aim of this study was to estimate the prevalence of osteopenia and osteoporosis in pre and postmenopausal Mexican women in relation to men, and to that reported in Caucasia women. The study involved 4,821 apparently healthy subjects (without known risk factors for osteoporosis), 4,467 females and 354 males from 11 different centers of Mexican Republic, 20 to 90 years old, using DXA bone densitometry of lumbar spine and hip. Prevalence of osteoporosis in women is twice that in men (P < 0.001), and it increases with age, particularly after the menopause (P < 0.0001). Our study found a prevalence of osteoporosis of the lumbar spine and/or hip in apparently healthy postmenopausal Mexican women over 50 years of age of 16%, increasing to 20% in those women with or without risk factors who attended voluntarily or by suggestion of their physician to be studied. The prevalence values obtained seem to be lower than those reported for Caucasian women, 30%. We found a prevalence of osteoporosis of 16% and of osteopenia of 57% in women 50 years of age and older. We also found a higher prevalence of osteoporosis in women of the south east part of the county.

Female↗
PubMed1999

Paternity analysis when the putative father is missing: first case in Chile.

Genetic marker analysis is a powerful tool for solving paternity-related problems when the putative father is missing. This report describes the first time this approach was employed in Chile to solve such a problem. In the case presented, the alleged father was missing as a result of the political detentions that took place in Chile during 1973. It was not possible to obtain any biological sample from him because he was missing. Thus, the case was resolved by means of genetic marker analysis of the alleged father's close relatives.

Birth Certificates↗
PubMed1999

[Paternity analysis using four DNA markers amplified by polymerase chain reaction].

BACKGROUND: DNA typing in forensic analysis is a useful tool to analyze paternity due to its high discrimination power. AIM: To report the experience of Servicio Medico Legal in Santiago, resolving cases of dubious paternity. SUBJECTS AND METHODS: Four highly polymorphic loci, amplified by polymerase chain reactions, were analyzed in 153 cases of uncertain paternity. The paternity index was calculated for each case. RESULTS: The four genetic markers analyzed provided an exclusion probability of 0.933 for the general population in Santiago. Thirty-seven cases were excluded as parents. In 31 cases, the paternity index ranged from 19 to 100, considered as probable paternity and 77 cases had an index of over 100, considered as almost certain paternity. Eight cases had an index between 0.5 and 19, considered as inconclusive. All loci met Hardy-Weinberg expectations and their frequencies were similar to other data from people living in Santiago. CONCLUSIONS: The use of these genetic markers proved to be very useful, reliable and with a high exclusion power for paternity analysis.

DNA↗
PubMed1996

Assessment and accreditation of Mexican medical schools.

With the objective of evaluating and accrediting the quality of medical education in the country, the Mexican Association of Medical Schools initiated the National Programme for the Strengthening of the Quality of Medical Education (PNFCE). This programme led to the establishment of the National System of Accreditation. Medical school deans in Mexico determined the criteria for the evaluation of quality and its subsequent standards through a consensus process. The following 10 criteria resulted: general basis and educational objectives; government and institutional orientation; educational programme and academic structure; educational process assessment; students; teaching staff; institutional coherence; resources; clinical sites; and administration. Eighty-eight standards were developed in the instrument designed for the self-evaluation phase. The information resulting from the self-evaluation will be verified by a group of experts during a survey visit, which will be finalized with a report to serve as the basis for the decision to be made by the Accreditation Commission. The self-evaluation phase started in 1994. In 1996 four schools submitted their request for accreditation. As of July 1996, one survey visit has been completed and three more are programmed for the second half of the year.

Accreditation↗
PubMed1996

[Paternity determination in cases of incest using multiallelic loci DNA polymorphisms].

The analysis of genetic markers in man allows to efficiently resolve cases of dubious paternity. Lately, the use of genetic markers derived from DNA analysis allows high exclusion probabilities. A particular case are those consultations whom the progenitors are closely related, in which the criteria to attribute paternity are modified. The present report explains the analysis methods and interpretation of results in situations of doubtful paternity in cases of incest between father and daughter, using monolocus DNA polymorphisms. The method is illustrated through the analysis of four cases seen at the Servicio Médico Legal of Santiago. To be able to determine paternity in these cases of incest, at least three multiallelic loci in which mother and son have different genotypes must be examined.

Alleles↗
PubMed1995

Smoking and its effects on maternal body composition in late pregnancy.

OBJECTIVE: To assess the possible impact of smoking on body composition at the 34-39 weeks of pregnancy, and its consequences on birth weight. SUBJECTS: 31 smokers and 31 non-smokers matched by age, gestational age and percentage of standard weight (PSW). Smoking mothers had 5 cigarettes or more per day during the whole period of pregnancy and non-smoking mothers never smoked. METHODS: A cross-sectional study was conducted in an urban Public Health Center. Anthropometry and the deuterium dilution technique were used to determine body composition. The statistical analysis used a t-test for matched pairs to assess significance of the means difference for each variable. RESULTS: Suprailiac and subscapular skinfolds were found to be larger in non-smokers; this difference was significant for the suprailiac skinfold (P < 0.05). No significant difference was found in total body fat, total body water and fat-free mass obtained with the deuterium dilution technique, or FFM determined by anthropometry. Infants' birth weight was similar in the two groups of mothers. CONCLUSION: These findings suggest that pregnancy does not modify the pattern of body fat distribution already present in smokers before conception. Infants' birth weight was similar in both groups, probably due to no difference in fat-free mass and body fat. The physiological effect of nicotine (e.g. on prolactin, micronutrients), seems to be clearer during lactation and infant growth.

Adult↗
PubMed1993

[Effects of lyophilization on four biological activities of Bothrops atrox venom (Serpentes: Viperidae)].

Fresh venom was obtained by milking both sexes of adult Bothrops atrox snakes. Four biological activities were studied in both fresh and freeze dried venom: local hemorrhagic in guinea pig skin, proteolytic upon casein (caseinolytic), esterasic upon TAME and fibrinogen clotting activity. All activities were detected in fresh venom: Hemorrhagic (DHM = 0.93, DHR = 9.75 micrograms protein), caseinolytic (0.25 U kunitz/mg protein), esterasic (0.70 U/mg protein) and clotting activity (75.7 U NIH/mg protein). After freeze drying, all the biological activity of B. atrox venom enzymes decreased: hemorrhagic, caseinolytic and clotting activity in 50% and the esterasic activity only in 15%. Our results show that lyophylization decreases several important biological activities in snake venom related to a decrease in the venom enzymatic activities.

Animals↗
PubMed1993

[Molecular genetic study of a severe growth hormone deficiency in a Chilean family].

The first and so far the only form of isolated growth hormone deficiency to accede to molecular genetic analysis is IGHD 1A, which has an autosomal recessive mode of inheritance. Several sizes of growth hormone gene deletions, ranging from 6.7 to 8.5 Kb are responsible for IGHD 1A. It has been reported that children with IGHD 1A have an initial good response to growth hormone treatment, followed by growth failure associated with the development of blocking antibodies against growth hormone. The effectiveness of treatment has been associated to the size of the gene deletion. We performed a molecular genetic analysis of the growth hormone locus, using Southern Blot and PCR techniques, to a 12 years old girl who fulfilled the criteria for IGHD 1A and her closer relatives. The results showed a 7 Kb deletion for the growth hormone gene in the girl and one of her brothers.

Child↗
PubMed1992

[Hemolytic disease of the newborn due to ABO incompatibility. A predictive test].

A direct 2 stage enzymatic test and the direct anti gamma globulin test were used to predict hemolytic disease of the newborn. Maternal allo-antibodies were determined in cord blood of all newborns from April to June 1988. 0.25% bromelase was used for the 2 Stage Enzymatic Test and a polyspecific anti-gammaglobulin serum was used for the Anti Gamma Globulin Test. Of 618 newborns 97 had parental ABO heterospecificity. Maternal allo-antibodies were present in 20 cases (3.2%). 20 of 86 fullterm newborns developed jaundice presumably due to ABO incompatibility. Blood exchange was required in 6, while phototherapy was sufficient in the rest. The 2 Stage Enzymatic Test was positive in 20 of these cases and the Anti Gamma Globulin Test was positive in 10. Thus, these tests may be used to predict hemolytic disease of the newborn due to ABO incompatibility.

ABO Blood-Group System↗
PubMed1991

[Incidence of insulin-dependent diabetes mellitus in the metropolitan region].

We used a retrospective search and confirmation method to establish the number of new cases of insulin dependent diabetes mellitus diagnosed between Jan 1, 1986 and Dec 31, 1989 in subjects under 15 years of age in the Metropolitan region of Chile. All hospitals and outpatient facilities of the National Health Service, other hospitals and private offices of endocrinologists and specialists in diabetes were surveyed, as well as the registry from the Juvenile Diabetes Foundation. A total of 115 cases, 52 in males and 63 in females were found, for an annual incidence of 1.69 and 2.15 per 100,000, respectively. Overall, the annual incidence rates were 2.22 in 1986, 1.22 in 1987 (p < 0.001), 2.13 in 1988 and 2.09 in 1989. A greater number of cases was diagnosed at age 4 in males and at age 12 in females (p < 0.001). The greater number of cases were diagnosed from June to August (winter) and the lowest in October (p < 0.001).

Adolescent↗
PubMed1991

The dose-to-mother method to measure milk intake in infants by deuterium dilution: a validation study.

A validation study of the dose-to-mother deuterium dilution method to measure breast-milk intake has been carried out on ten infants from a Nutrition Recovery Centre in Santiago, Chile. Formula milk labelled with exponentially decreasing doses of deuterium oxide represented milk from a 'pseudo mother' of these exclusively bottle-fed infants. Unlabelled formula represented milk from other sources. Deuterium levels in the infants' body water were measured on saliva samples by mass spectroscopy. The data were fitted in a two-compartment steady-state model of the mother-child system to estimate the flow of labelled water from the 'mother' to the infant and the 'mother' and infant's water elimination constants. A dose-to-child experiment was also carried out on each infant to determine the deuterium dilution space and total daily water intake. Total and labelled water flows from deuterium dilution were used to calculate total, labelled and unlabelled formula milk intakes which were compared to the same quantities measured by bottle weighing. Water elimination constants calculated from the dose-to-mother experiments underestimated by 17 per cent the initially set mother constant and overestimated by 21 per cent the infant constants calculated from the dose-to-child experiments. Rate constants, however, have little effect on the estimated water flows so that there was good agreement between values from deuterium dilution and from direct weighing. Mean (SD) total formula, labelled formula and unlabelled formula intakes were 865 (129) g/d, 417 (74) g/d and 448 (106) g/d, respectively, when measured by deuterium dilution, compared with 856 (116) g/d, 414 (71) g/d and 441 (68) g/d when measured by direct weighing. The mean per cent differences were 1.1 per cent, 0.7 per cent and 1.6 per cent and the mean absolute differences for individuals, 4.3 (1.9) per cent, 4.8 (3.1) per cent and 9.7 (6.6) per cent, respectively.

Deuterium↗