Sensibilidad y especificidad del examen directo micológico con blanco de calcoflúor para el diagnóstico de onicomicosis / Sensitivity and specificity of mycological direct examination with calcofluor white for the diagnosis of onychomycosis

INTRODUCCIÓN: La creciente importancia de la onicomicosis, no sólo por el aumento en su frecuencia sino también por el incremento de patógenos emergentes, plantea un reto diagnóstico y terapéutico. MATERIAL Y MÉTODOS: Estudio comparativo, abierto, observacional y transversal de pacientes con diagnóstico clínico de onicomicosis y se comparó la utilidad diagnóstica del examen directo con KOH-negro de clorazol y el blanco de calcoflúor, tomando como estándar de oro la biopsia de la porción distal de la lámina ungueal teñida con PAS. RESULTADOS: Se incluyeron 165 pacientes (70% mujeres), el 79,4% fueron positivos para onicomicosis (OSDL 50,9%) en uñas de pies (89%) con 6años de evolución. Se reportó una sensibilidad: KOH-negro de clorazol 90,12% (95% CI: 81,46%-95,63%) vs blanco de calcoflúor 86,42% (95% CI:76,99%-93,01%) y una especificidad de 50% para KOH-negro de clorazol (95% CI: 38,89%-61,11%) vs 60,71% para blanco de calcoflúor (95% CI:49,45%-71,20%). Así mismo, se registró un VPP de 63,48% para KOH-negro de clorazol (95% CI: 53,99%-72,26%) y de 67,96% para blanco de calcoflúor (95% CI: 58,04%-76,81%) y un VPN de 84% (95% CI: 70,88%- 92,81%) y 82,26% (95% CI: 70,46%-90,78%), respectivamente. Comentario: El examen directo con blanco de calcoflúor resulta una buena herramienta diagnóstica debido a que es altamente sensible, requiere de poca experiencia por parte del observador, se realiza mediante un procesamiento sencillo, que consume poco tiempo y es de bajo costo

INTRODUCTION: The growing importance of onychomycosis, not only by the increase in frequency but also by the rise of emerging pathogens poses a diagnostic and therapeutic challenge. MATERIAL AND METHODS: A comparative, open, observational, transversal, which included patients with clinical diagnosis of onychomycosis and compared the diagnostic utility of direct examination of KOH-chlorazol black and calcofluor white, on the gold standard biopsy of the distal portion of the nail plate stained with PAS. RESULTS: We included 165 patients (70% women), 79.4% were positive for onychomycosis (OSDL 50.9%) in toenails (89%) with 6 years of evolution. They reported a sensitivity: KOH-black of chlorazol 90.12% (95% CI: 81.46% -95.63%) vs86.42% calcofluor white (95% CI: 76.99% -93.01%) and aspecificity of 50% KOH-black of chlorazol (95% CI: 38.89% -61.11%) vs 60.71% for calcofluor white (95% CI: 49.45% -71.20%). Also, there was aPPV of 63.48% for chlorazol KOH-black (95% CI: 53.99% -72.26%) and 67.96% for calcofluor white (95% CI: 58.04% -76.81%) and a NPV of 84%(95% CI: 70.88% - 92.81%) and 82.26% (95% CI: 70.46% -90.78%), respectively. Comment: The direct examination with calcofluor white is a good diagnostic tool because it is highly sensitive, requires little expertise on the part of the observer, is performed by simple processing, which consumes little time and is inexpensive

[Evaluation of the indoor and outdoor air quality in a nursery school in Mexico City]. / Evaluación de la calidad del aire interior y exterior en un jardín de niños de la Ciudad de México.

OBJECTIVE: To evaluate the differences between indoor and outdoor ozone (O3) and nitrogen dioxide (NO2) levels at a school located in southwest Mexico City. MATERIAL AND METHODS: Indoor and outdoor O3 and NO2 levels were measured daily between January and April 1990 by manual monitoring. RESULTS: Indoor and outdoor concentrations of nitrogen dioxide did not surpass the Mexican standard (0.21 ppm). The correlation coefficient between maximum NO2 concentrations measured by the city's local monitoring station and those measured outside the classroom was 0.82 (p < 0.001). Regarding ozone, its maximum outdoor concentration was 0.29 ppm and indoor concentrations were on average below 0.06 ppm (maximum = 0.17 ppm). The indoor/outdoor correlation coefficient was 0.72, and for every 1.7 ppm outside, there was 1.0 ppm inside (p < 0.05). CONCLUSIONS: Since the highest outdoors O3 concentrations were observed between 11:00 and 14:00 hrs, it is recommendable to have recess before this time.

[Cost-benefit analysis of the Program for Early Screening of Cervico-uterine Cancer]. / Análisis costo beneficio del Programa de Detección Oportuna del Cáncer Cervicouterino.

OBJECTIVE: Previous researches pointed out the critical changes needed to increase the efficiency of the National Screening Programme of Cervical Cancer in Mexico. These changes were assessed through a cost-benefit analysis. This paper presents the results of that appraisal. Figures are presented as US Dollars of 1996 valued as 7.5 pesos for each dollar. RESULTS: The operational unitary cost of the integral process of the cytology-the obtention of the Pap smear, its transportation to the interpretation centre, its analysis, and the notification of results to users-was estimated in US$ 11.6. If the proposed changes are operated, the cost of each citology would increase by 32.7%. The benefit/cost ratio would be 2 and the net benefit of 88 millions of US dollars for the next five years. CONCLUSIONS: The operation of the proposed changes is socially desirable, but should be supported the training activities of the personnel, the increase of the coverage of women at risk, the quality control activities, the monitoring of the program and the communication with women detected as positive cases.

Trends of lung cancer mortality in Mexico.

Lung cancer (LC) is one of the most important public health problems in the world; 1,035,000 annual deaths are estimated each year and more than 80% of these are attributed to tobacco. The trend of lung cancer mortality in Mexico City from 1979 - 1993 was determined, as was the rate ratio of lung cancer mortality in 31 states in Mexico, taking Mexico City as a reference by means of a Poisson model. A strong linear regression model was used to evaluate the rate, where the dependent variable was LC mortality rate and the independent variable the year observed. In 15 years, 73,807 deaths from LC were reported, with an increase in mortality from 5.01 - 7.25 per 100,000 inhabitants. Mortality increases significantly after 60 years of age (B not equal to 0), p<.05) in men and in women. Mortality from LC was 70% in men, and more than 60% of deaths were reported after 65 years of age. Mortality risk is higher in the northern states of the country (e.g., Sonora, RR=2.40) than in the southern region (e.g., Oaxaca RR=0.40). In Mexico, almost 10,000 deaths by LC are estimated for the year 2010. Therefore, changes in lifestyle should be encouraged in order to decrease the smoking habit. The governmental tax on cigarettes should be increased, smoking restricted in squares and public spaces, and the risks should be announced on cigarette packages, among other measures. With respect to other emergent risk factors, the sources of industrial pollution and toxic emissions should be regulated.

[Effect of environmental pollution on medical visits for respiratory infections in children in Mexico City]. / Efecto de la contaminación ambiental sobre las consultas por infecciones respiratorias en niños de la Ciudad de México.

OBJECTIVE: To model the variability of medical visits by children for respiratory reasons as a consequence of the daily changes in environmental pollution observed in the emergency and family medicine departments of a hospital of the Instituto Mexicano del Seguro Social located in the southwest of Mexico City during 1993. MATERIALS AND METHODS: The correlation between the presence of upper and lower respiratory tract infections and exposure to ozone and nitrogen dioxide was studied. To model this association, the authors used multivariate Poisson regression models with linear and non-linear risk, with lag periods between the environmental measurements and the medical visits of one, two and three days, as well as the average of the measurements of three, five and seven days previous to the visit. RESULTS: The model estimates that an increment of 50 ppb in the daily average of ozone would cause an increase of 9.9% in emergency visits due to high respiratory tract infections during the winter, which could rise to 30% if the increment would last five consecutive days in average. CONCLUSIONS: Results suggest that exposure of children younger than 15 years of age to ozone and nitrogen dioxide significantly affect the number of medical visits for respiratory causes in this part of Mexico City.

Exercise and reproductive factors as predictors of bone density among osteoporotic women in Mexico City.

We examined the association between physical activity and reproductive factors with bone density among 313 Mexican women, aged 26-83 years. Bone mineral density (BMD) was measured with a HOLOGIC QRD 1000 w, DXA densitometer at the lumbar spine and femoral region. We explored the relation between BMD and parity, age, body mass index (BMI), type of menopause, and level of exercise. Multiple regression models examining determinants of bone density at the lumbar and femoral regions showed that increasing age and lack of exercise were statistically significant predictors of bone demineralization. The number of pregnancies also had a deletereous effect on bone density, especially for lumbar spine, as well as BMI <20 kg/m2. Our results suggest that physical activity, parity, and BMI are important determinants of bone density in this population.

[Asthma in a population of children and its relation to airborne environmental pollutants in Mexico City. A cohort study. Mexico, 1991. Experimental design]. / Asma en población infantil y su relación con los contaminantes ambientales aéreos de la ciudad de México. Un estudio de cohorte. México, 1991 Diseño metodológico.

We developed a panel study to evaluate the association between intermittent exposure to ozone and acute attack of asthma. The population study consists in 136 asthmatic children residents in the southwest and northeast of Mexico City. They were attended in the allergic services of the two main Pediatric Hospital of Mexico City. In this paper we present the methodological issues following in the study and the results of the descriptive analysis of the relation between ozone exposure and acute attack of asthma.

[Accidents and injuries in 4 general hospitals of the Distrito Federal]. / Accidentes y lesiones en cuatro hospitales generales del Distrito Federal.

We report the injuries for "E" code in 10191 subjects attending four general hospitals of Mexico City. Seventy-nine per cent of them were males and 29.1 per cent were females. THe highest utilization rate of the care unit was during weekends. Only 14 per cent of the study population were admitted to the hospital. People classified as drunk were more likely to have more severe injuries and to be admitted to the hospital and female drinkers had the highest risk of hospitalization (RR = 3.03; IC = 1.85-5.04). Only in 49 per cent of the cases was the external cause of injury coded The main causes were gunshots and stabbing with knife or cutting weapon. In this study we found a greater proportion of fractures in women than in men, pointing toward the possible presence of osteoporosis in the female population.

Blood lead level and neurobehavioral development among children living in Mexico City.

This cross-sectional study examined the association between blood lead levels and neuropsychological and behavioral development of 139 children (7-9 y of age) who attended school in the southwestern part of Mexico City. A trained psychologist administered an IQ test to 84% of the children, and teachers graded them for agility, socialization, expression, and knowledge. Parents also answered a questionnaire on demographic and socioeconomic variables. Anodic stripping voltametry was used to determine blood lead levels. Regression models were used to determine the best predictors of IQ and teachers' rating scores. The mean blood lead level was 19.4 micrograms/dl (standard deviation [SD] = 7.6), with a geometric mean of 17.8 micrograms/dl (95% confidence interval [95% CI] = 16.5-19.1). Blood lead was the strongest predictor of full-scale IQ, and there was a significant negative trend between blood lead, full-scale IQ, and teachers' rating scores. In this study, children with higher levels of blood lead performed more poorly on psychometric tests and had poorer educational attainment than their counterparts. These results suggest an association between neuropsychological and behavioral impairment and lead exposure.

[Epidemiologic investigation of measles in Mexico. A methodological proposal]. / La investigación epidemiológica del sarampión en México. Propuesta metodológica.

The epidemiological study of measles needs a critical perspective in addition to a descriptive study of variables in time, place and person. The goal of this critical and methodological study of measles is to evaluate the coverage and efficacy of the vaccine in the affected population. These indicators will provide an indirect evaluation of the preventable services. This document presents a general view of the epidemiological design of cohorts and case-control studies and their immediately application to the study of measles. It describe the mathematical procedures for calculating the coverage and efficacy of the measles vaccine in community and hospital outbreaks.