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Biomedical subjects

H Gutiérrez

Publications and source records attributed to H Gutiérrez.

17 recordsLinked to original sources
PubMed2001

Unusually high prevalence rates of obesity in four Mexican rural communities.

OBJECTIVE: To establish the nutritional status of previously studied rural populations. DESIGN AND SUBJECTS: A total of 139 households with 245 males and 301 females from four relatively isolated Mexican rural communities were randomly selected to be surveyed in 1996. RESULTS: Underweight was not a problem in either children or adults. In children <5 y only three (4.2%) were stunted but the age- and sex-specific distributions of body mass index (BMI) in children showed 17% of boys and 19% of girls exceeded the proposed International Obesity Task Force limits for classifying the overweight. Triceps skinfold values were similar to NHANESI values for white USA children. Of the adult men 42% were overweight (BMI 25.0-29.9) and 9% obese; 40% of adult women were overweight and a further 33% obese. Adjusting BMI values with corrected total heights by relating them to measured knee height reduced the BMI of women >50 y by 2.0 units; the male data were essentially unchanged. The prevalence of abdominal obesity in women, based on waist measurements and WHO cut-off points was high with 25% of women having elevated values despite a normal BMI; 43% of the overweight women had substantial increases in waist measurements, indicative of high risk, as did 91% of obese women. The men's waist measurements were greater in relation to both BMI and body fat but the prevalence of values in excess of the suggested sex-specific WHO limits was less than half that of women. CONCLUSIONS: The high prevalence of overweight and obesity is now evident in poor and relatively isolated rural communities of Mexico. SPONSORSHIP: The Chronic Disease Office, from the Ministry of Health in Mexico partially financed this study.

Adipose Tissue↗
PubMed2000

Differential participation of the NBM in the acquisition and retrieval of conditioned taste aversion and Morris water maze.

Deficits in both learning and memory after lesions of the cholinergic basal forebrain, in particular the nucleus basalis magnocellularis (NBM), have been widely reported. However, the participation of the cholinergic system in either acquisition or retrieval of memory process is still unclear. In this study, we tested the possibility that excitotoxic lesions of the NBM affect either acquisition or retrieval of two tasks. In the first experiment, animals were trained for two conditioned taste aversion tasks using different flavors, saccharine and saline. The acquisition of the first task was before NBM lesions (to test retrieval) and the acquisition of the second task was after the lesions (to test acquisition). Accordingly, in the first part of the second experiment, animals were trained in the Morris water maze (MWM), lesioned and finally tested. In the final part of this experiment, another set of animals was lesioned, then trained in the MWM and finally tested. All animals were able to retrieve conditioned taste aversion (CTA) and MWM when learned before NBM lesions; however, lesions disrupted the acquisition of CTA and MWM. The results suggest that the NBM and cholinergic system may play an important role in acquisition but not during retrieval of aversive memories.

Acetylcholinesterase↗
PubMed1999

Redundant basal forebrain modulation in taste aversion memory formation.

Mnemonic deficits resulting from excitotoxic lesion of the basal forebrain have been classically attributed to the resulting depletion of cortical acetylcholine activity. It has been demonstrated that in spite of the strong cholinergic depletion after injections into the basal forebrain of the immunotoxin 192IgG-saporin, no detectable deficit can be found in the acquisition of several learning tasks, including conditioned taste aversion. Conversely, NMDA-induced lesions of the basal forebrain strongly impair taste aversion learning. In this study we show that 192IgG-saporin produces an efficient and selective cholinergic deafferentation of the rat neocortex but not the amygdala. Furthermore, a stronger relationship between severity of memory impairment after NMDA lesions and basoamygdaloid cholinergic deafferentation was found. Therefore, in a second experiment, we show that combining NMDA-induced lesions into the basolateral amygdala with 192IgG-saporin injections into the basal forebrain results in a strong disruption of taste aversion learning, whereas none of these treatments were by themselves capable of producing any detectable impairment in this learning task. The double lesion effect was only paralleled by simple NMDA lesions into the basal forebrain, suggesting that the learning deficits associated to excitotoxic lesions of the basal forebrain are the result of the simultaneous destruction of the corticopetal and basoamygdaloid interaction. A model is proposed, according to which the modulation of learning processes exerted by the basal forebrain can be redundantly performed by both the basocortical and basoamygdaloid pathway.

Acetylcholinesterase↗
PubMed1999

Differential effects of 192IgG-saporin and NMDA-induced lesions into the basal forebrain on cholinergic activity and taste aversion memory formation.

Mnemonic deficits resulting from excitotoxic lesion of the basal forebrain have been classically attributed to the resulting depletion of cortical acetylcholine activity. In this study, we have performed a detailed analysis of the cholinergic status of the insular cortex (IC) following local injections of either 192IgG-saporin (192IgG-sap) or N-methyl-D-aspartate (NMDA) directly into the nucleus basalis magnocellularis (NBM). By means of in vivo microdialysis, we show that the immunotoxin lesion results in an almost complete lack of extracellular acetylcholine release, whereas NMDA-induced lesions result in a marginal reduction in cortical cholinergic activity. Choline-acetyltransferase activity in the IC further confirmed this differential pattern of cortical deafferentation. Surprisingly, however, only NMDA-induced lesions showed a strong disruptive effect upon taste aversion learning whereas no detectable deficits could be found following 192IgG-sap lesions. By combining intrabasal injections of 192IgG-sap with acute pre-training infusions of the cholinergic antagonist scopolamine into the IC, a strong disruption of taste aversion was attained. These results imply that residual cholinergic activity, following 192IgG-saporin lesions, might be still critical for normal cortical mediation of memory processing. They also support the role of basal forebrain in mediating learning and memory processes, and demonstrate that mnemonic deficits resulting from excitotoxic lesions of the basal forebrain are not the sole result of cortical acetylcholine activity hypofunction.

Acetylcholine↗
PubMed1999

Blockade of N-methyl-D-aspartate receptors in the insular cortex disrupts taste aversion and spatial memory formation.

The present experiments examined the effects of direct intracortical microinjections of the N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonovaleric acid directly into the insular cortex of rats, before or immediately after training of conditioned taste aversion and the water maze spatial learning task. In the first series of experiments animals received bilateral injections of 2-amino-5-phosphonovaleric acid prior to taste aversion conditioning or spatial training. A strong disruptive effect was found in the acquisition of training tasks. To determine the possible involvement of N-methyl-D-aspartate receptors in the early post-training processes taking place in the cortex during both learning paradigms, in a second series of experiments, animals received bilateral 2-amino-5-phosphonovaleric acid microinjections 30, 60 or 120 min after the acquisition trial, and 15 min before the retention test. For spatial learning successive treatments were independently done either starting at the onset of the asymptotic phase of the learning curve, 0, 30 or 120 min after finishing the training session, as well as 15 min before the retention test trial. The conditioned taste aversion task remained sensitive to N-methyl-D-aspartate blockade during a period of at least 2 h after the first presentation of the gustatory stimulus, while in the case of the spatial learning task, a gradually decreasing effect was observed from the onset of the asymptotic phase onwards. Taken together, these results provide direct evidence for N-methyl-D-aspartate receptor involvement in cortical regulation of memory formation. Furthermore, our results suggest that in the same cortical region, a different time-course for the activation of N-methyl-D-aspartate-dependent mechanisms occurs during the early formation of cortically mediated memories, depending on the particular behavioural task.

2-Amino-5-phosphonovalerate↗
PubMed1997

Learning impairment and cholinergic deafferentation after cortical nerve growth factor deprivation.

Cholinergic basal forebrain (CBF ) neurons have been shown to respond in vivo to exogenous administration of NGF. Although neurotrophins and their receptors are widely expressed in the CNS, little data exist for the physiological significance of endogenous neurotrophin signaling in CNS neurons. To test directly whether cortically derived NGF is functionally required for the cholinergic functions mediated by the cerebral cortex, repeated injections of anti-NGF mAbs were locally applied into the insular cortex (IC) of rats. The biochemical results, using an in vivo microdialysis technique, showed a dramatic lack of extracellular release of acetylcholine after high potassium stimulation compared with controls. Furthermore, by using small injections of the neurotracer fluorogold, we found a corresponding disruption in the connectivity between the IC and the CBF. Behavioral experiments showed that the NGF antibodies applied into the IC produced a significant disruption on the acquisition of conditioned taste aversion and inhibitory avoidance learning. However, the same animals were able to recall the taste aversion when the conditioning trial was established before injections of NGF antibodies. Given these results, it seems that cortical cholinergic functions are actively dependent on locally derived NGF in the adult normal brain, and that the cholinergic activity from the CBF is not necessary for recalling aversive stimuli, but is necessary for the acquisition of aversively motivated conditionings.

Age Factors↗
PubMed1989

The use of oral hydration in the treatment of children with acute diarrhea in primary care.

The use of oral rehydration solutions (ORSs) for treating children with diarrhea is spreading in hospitals in Chile, but it has not yet been incorporated into routine primary care programs. We sequentially compared the effectiveness of an ORS, with 60 mmol/L of Na+, with the standard treatment for diarrhea used in primary care centers, in a study with 285 diarrheal children under 2 years of age who consulted a health center in a low-income periurban neighborhood of Santiago. When compared with the control group, the patients treated with ORS showed a significantly higher percentage weight gain in the first few days after treatment was begun, required fewer medical visits for follow-up treatment at other facilities (8.4 vs. 15.5%; p less than 0.05), and experienced fewer episodes of subsequent clinical dehydration that needed rehydration (oral or intravenous) in emergency services (2.8 vs. 10.6%; p less than 0.01). In addition, there were no metabolic complications in either group. Our results reinforce the feasibility, efficaciousness, and safety of programs that use ORS at the primary care level and indicate that this is an effective method of preventing metabolic complications and reducing hospitalizations of children with acute diarrhea.

Chile↗
PubMedDate not supplied

[The choice of career and the prospects for the professional development of students of medicine].

This paper is based on a survey on 1,044 medical students during the 3rd, 4th and, 5th year of the career, internship and social service in four different medical schools in Mexico City's metropolitan area. Their motivations for studying medicine and their perspectives for professional development are analyzed. More than 90% decided on their own to study medicine, about 60% decided to study medicine for personal satisfaction, 50% have relatives in the field, 90% wish to become specialists and the same percentage would like to work in a public institution. About 60% of the students believe they will find a job immediately after finishing their training.

Adult↗