Biomedical subjects

Ignacio Méndez-Ramírez

Publications and source records attributed to Ignacio Méndez-Ramírez.

8 recordsLinked to original sources

PubMed2004

A cluster analysis model for caries risk assessment.

Cluster analysis was applied to determine, the natural grouping of individuals, among sixty 8-10-year-old children, and to identify the most significant set of markers for risk assessment. The risk clusters were obtained with initial clinical and bacteriological measurements including dmf + DMFS, active caries, mutans streptococci and lactobacilli counts in plaque or saliva on two media, and Snyder's test results. The morbidity clusters were constructed with the final clinical indexes and incidence after 18 months (dependent variables). A risk cluster was identified that included the following significant initial variables; dmf + DMFS, active caries, counts of mutans streptococci from plaque on TSY20B and lactobacilli in saliva, and Snyder's test results. This set of markers identified 86% of the children at high risk who developed high morbidity, as well as 94% of children in the low-risk cluster who developed low or no caries. The results of this investigation provide the basis to develop a system for caries risk assessment.

Child↗

PubMed2003

Methods of the National Nutrition Survey 1999.

OBJECTIVE: To describe the methods and analyses of the 1999 National Nutrition Survey (NNS-99). MATERIAL AND METHODS: The 1999 National Nutrition Survey (NNS-99) is a probabilistic survey with nationwide representativity. The NNS-99 included four regions and urban and rural areas of Mexico. The last sampling units were households, selected through stratified cluster sampling. The study population consisted of children under five years of age, school-age children (6-11 years), and women of childbearing age (12-49 years). Data were collected on anthropometric measurements, hemoglobin levels, morbidity and its determinants, and socioeconomic and demographic characteristics. In addition, data on diet and micronutrients intakes (iron, zinc, vitamin A, folic acid, vitamin C, and iodine) were obtained in a sub-sample of subjects. RESULTS: The response rate for the NNS-99 was 82.3%; the non-response rate was 5.9% and the remaining did not participate due to uninhabited houses. CONCLUSIONS: This survey updates the information on nutritional status in Mexico and should serve as the basis for food and nutrition policy-making and priority program design. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Adolescent↗

PubMedDate not supplied

Prediction equations for spirometric parameters in Mexican adult population.

BACKGROUND: Our objective was to develop prediction equations for spirometric parameters that included the following: forced vital capacity (FVC); 1st-sec forced expiratory volume (FEV1); FEV1/FVC ratio; peak expiratory flow (PEF); maximal expiratory flow 50% FVC (VF50) and maximal expiratory flow 75% FVC (VF75); maximal mid-expiratory flow (FEF25-75), and forced late expiratory flow rate (FEF75-85) in a sample of adult Mexican population of both sexes. Age and height variables were utilized. METHODS: Spirometric studies were carried out, observing the international recommendations and norms in force and effected under basal conditions and post-bronchodilator. Linear regression equations were generated based on gender, age, and height. For each spirometric parameter, we selected a linear model. Studies were carried out with spirometry that was in agreement with quality criteria recommended by the American Thoracic Society (ATS). Bronchodilatator administration allowed for elimination of subjects with subclinical bronchial hyperreactivity RESULTS: We studied 436 patients with normal clinical radiographic and pulmonary function, with negative smoking and age range between 17 and 63 years; 206 were females and 230, males. Linear regression equations obtained had direct linear correlation with height and inverse linear correlation with age; in addition, equations had a determination coefficient equal to or less than those reported by authors recommended by the ATS. CONCLUSIONS: Equations obtained in this study possessed the quality required for application in adult Mexican population exposed or not to occupational and environmental contaminants.

Adolescent↗

PubMedDate not supplied

Healing of chronic arterial and venous leg ulcers through systemic effects of electromagnetic fields [corrected].

BACKGROUND: Mitogen-activated autologous peripheral blood mononuclear cells applied locally on the ulcer surface promote healing of chronic arterial and venous leg ulcers. In vitro, extremely low frequency electromagnetic fields (ELF) interact with peripheral blood mononuclear cells (PBMC) via Ca++ channels, activating signal transduction cascades, promoting cytokine synthesis, and changing cell proliferation patterns. METHODS: ELF frequencies were configured to interact in vitro with the proliferation patterns of PBMC obtained from normal human volunteers. These ELF were then applied peripherally as the sole treatment to 26 patients with 42 chronic leg ulcers of predominantly arterial or venous etiology unresponsive to previous medical and/or surgical treatments in a phase I before-after design. RESULTS: At admission, age of ulcers had a skewed distribution with a median of 639 days. Wound healing or deleterious effects began in all patients during the first 2 weeks after ELF exposure, permitting their previously unresponsive ulcers to function as internal controls. After ELF exposure, 69% of all lesions were cured or healed >50% in a period <4 months. Defective wound healing was observed in lesions associated with important arterial occlusion, uncontrolled arterial hypertension, severe lipodermatosclerosis, non-pitting edema, and obesity (body mass index >30). Lesions worsened in patients with autoimmune diseases. CONCLUSIONS: Systemic effects are hypothetically explained by ELF activation of PBMC and their subsequent transportation to the ulcer site via humoral route. This therapy is effective in selected patients with chronic arterial and venous leg ulcers.

Arteries↗

PubMedDate not supplied

Esophageal anastomotic failure: an experimental study.

BACKGROUND: Postsurgical complications in patients with esophageal atresia have remained unchanged during the last three decades. This study was aimed at investigating certain risk factors for small-sized esophageal anastomosis and to assess the probable relationship between esophageal length and body weight in rabbit. METHODS: Six groups of 10 adult rabbits were subjected to section or 1-cm segmental resection of thoracic esophagus followed by end-to-end anastomosis. Approximation strength of esophageal ends was measured. Three different suture materials were used, and three different surgeons carried out procedures. Observed morbidity was recorded, as well as leakage or stenosis frequency in suture line. Esophageal length and body weight of nonresected rabbits were measured. RESULTS: Fifteen leakages were observed in suture line; there were no differences in relative risk between groups with and without resection, or in ratio of this complication among surgeons; nonetheless, a greater number of leakages (p < 0.05) was observed at higher tension. There were no differences in magnitude of stenosis among surgeons, tension degree, or suture material used. Quadratic association was found between length of thoracic esophagus and body weight in nonresected rabbits. CONCLUSIONS: Rabbit esophagus is a suitable model to assess early surgical complications but not for late complications. Among three assessed factors, increased tension in patients with segmental deficit was the most significant factor in development of anastomotic leakage. Existence of nonlineal correlation between esophageal length and body weight in rabbit showed that resection of 1 cm of esophagus represented a different weight-dependent segmental deficit, which increased as weight decreased.

Anastomosis, Surgical↗

PubMedDate not supplied

Computer use increases the risk of musculoskeletal disorders among newspaper office workers.

BACKGROUND: Our objectives were to estimate prevalence of musculoskeletal disorders among office workers at a newspaper in Mexico City, analyze the relationship between musculoskeletal disorders and use of the personal computer (PC) and associated ergonomic factors in the aforementioned population, and to analyze the modifying effect that psychosocial factors have on the relationship between ergonomic factors and musculoskeletal disorders and extant jobs at the newspaper. METHODS: A total of 73% (218 of 298) of office workers at a newspaper were studied. Information was collected by a questionnaire completed by participants. Cases for work-related musculoskeletal disorder in hands (WMSD-H), upper extremity (WMSD-UE), and back (WMSD-B) were established. Working conditions, computer use, and ergonomic and psychosocial factors were studied as independent variables. To study the relationship between musculoskeletal disorders and independent variables, prevalence ratios adjusted for potential confounders (sex, age, educational level, and marital status) were estimated. RESULTS: Risk of musculoskeletal disorders was greater among workers at the newspaper who used computers, those involved in editing work, and those who adopted uncomfortable positions. The modifying effect of psychosocial factors was observed only in the relationship between ergonomic factors and WMSD-B because among workers with control over work, WMSD-B risk was reduced by the greater number of work breaks. Among workers without social support, increase in number of postures and rotation/inclination of the neck was associated with substantial risk increase, while amid workers under psychological demand number of PC tasks and number of rest pauses were associated with increase in WMSD-B risk. CONCLUSIONS: The findings of our study showed that PC use increased risk of developing musculoskeletal disorders (WMSD-H and WMSD-UE). Such an increase is mediated by ergonomic factors such as mouse use, remaining seated for prolonged periods, adoption of inadequate or uncomfortable postures, performing certain PC tasks, and psychosocial factors.

Adult↗

PubMedDate not supplied

[Adjustment of the Andersen's model to the Mexican context: access to prenatal care].

UNLABELLED: The aim of this work was to propose an adjustment to the Model of Andersen who answers better to the social inequality of the population in the Mexico City and allows to evaluate the effect of socioeconomic factors in the access to the prenatal care of a sample stratified according to degree of marginalization. MATERIAL AND METHODS: The data come from a study of 663 women, randomly selected from a framework sample of 21,421 homes in Mexico City. This work collects information about factors that affect utilization of health services, as well as predisposing factors (age and socioeconomic level), as enabling factors (education, social support, entitlement, pay out of pocket and opinion of health services), and need factors. The sample was ranked according to exclusion variables into three stratums. The data were analyzed through the technique of path analysis. RESULTS: The results indicate that socioeconomic level takes part like predisposed variable for utilization of prenatal care services into three stratums. Otherwise, education and social support were the most important enabling variables for utilization of prenatal care services in the same three groups. In regard to low stratum, the most important enabling variables were education and entitlement. For high stratum the principal enabling variables were pay out of pocket and social support. The medium stratum shows atypical behavior which it was difficult to explain and understand. There was not mediating role with need variable in three models. This indicated absence of equality in all stratums. However, the most correlations in high stratum perhaps indicate less inequitable conditions regarding other stratums.

Adolescent↗

PubMedDate not supplied

[Risks and health problems caused by the use of video terminals].

OBJECTIVE: To evaluate the association between video display terminal (VDT) use and health hazards, occupational risks, and psychosocial factors, in newspaper workers. MATERIALS AND METHODS: A cross-sectional study was conducted in 1998 in a representative sample (n = 68) drawn from a population of 218 VDT operators in Mexico City. Data were collected using a self-administered questionnaire. Data were confirmed by performing physical examinations. The research hypothesis was that both the current and cumulative use of VDT are associated with visual, musculoskeletal system, and skin illnesses, as well as with fatigue and mental or psychosomatic disorders. Occupational health hazards were assessed (visual problems, postural risks, sedentary work, computer mouse use, excessive heat, and overcrowding), as well as psychosocial factors related to work organization (psychological demands, work control, and social support). Prevalence ratios were adjusted for confounding variables like age, sex and schooling. RESULTS: Women were more likely than men to have upper extremity musculoskeletal disorders (MSD), dermatitis, and seborrheic eczema. VDT use was associated with neuro-visual fatigue, upper extremity MSD, dermatitis, and seborrheic eczema. Computer mouse use and postural risks were significantly associated with health problems. Psychosocial factors were mainly associated with mental problems, psychosomatic disorders, and fatigue. CONCLUSIONS: Intense use of video screens has been found to cause musculoskeletal disorders of the hand. The diversification of tasks and control of labor processes itself had a protective effect against psychosomatic disorders and pathological fatigue.

Adult↗