The aim of this study was to obtain the cut point to determine an individual's seronegativity with respect to measles using commercial reagents. To determine the test sensitivity, the serum of 22 ...individuals 21 years of age or older, and a positive history of measles (positive control group) was studied. For specificity, the serum of 22 children 15 to 24 months old, and no measles vaccination record nor positive history of measles (negative control group), was analyzed. The antibodies titer determination for both groups was done using the ELISA technique and the Brunell method, subsequently, as well as a ROC curve (Received Operating Curve). When the Brunell method was used, the cut points were 0.4090 (sensitivity 1.0 and specificity 0.95) and 0.5042 (sensitivity 0.95 and specificity 1.0). When a ROC curve was done the cut point was 0.4500, with a sensitivity and specificity of 100 per cent. It was also concluded that the latter is the best method to obtain this cut point, because it does not establish arbitrary values when the data distribution does not follow a normal pattern.
To determine children's perception of their own psychosocial functioning, to compare it with their parents' perception, and determine the type and rate of their psychopathological syndromes and ...family functioning, and to investigate correlation among these data. Nineteen children with craniofacial deformities and their parents responded to the Columbia Impairment Scale, the Child Behavior Checklist and the McMaster General Functioning Subscale. Psychosocial impairment is a trend in children with craniofacial deformities. There is a correlation between children's and parents' perception of the patient's psychosocial adaptation, global psychopathology and externalizing and aggressive syndromes. A less strong correlation was found with internalizing, somatization and attention deficit syndromes, and with family functioning. Craniofacial deformities in childhood pose special risks for psychosocial adjustment due to type of illness and environmental and family factors.
Usefulness of residuals in clinical research Cuevas-Urióstegui, M L; Garduño-Espinosa, J; Fajardo-Gutiérrez, A ...
Boletín médico del Hospital Infantil de México (Spanish edition)
50, Številka:
5
Journal Article
Recenzirano
The simple linear regression analysis, multiple linear regression and logistic regression constitute powerful statistical analysis tools widely used in clinical research. These kinds of analyses are ...based upon mathematical models which at the same time are established on certain basic assumptions. The regression analysis assumptions are basically: a) that the model is really linear, b) that the distribution of data is normal (from a statistical point of view), c) that the variances of the employed data are homogeneous (homocedastics) and that the included data are independent. The regression diagnostic has become popular as a form to evaluate if the assumptions have been accomplished, one of its most important techniques is the residual analysis. A residual can be defined as the value which measures the distance between the regression line and the corresponding value of the variable "y". Among these kinds of residuals used to evaluate the assumptions of regression are: the crude residual, the standardized, of student and the jackknife. The most useful among them is the jackknife residual. The usefulness and limitations of the residuals in the evaluation of the regression analysis assumptions are described, basically referring to the identification and handling of extreme values (outliers).
Prognostic factors in a pediatric intensive care unit Garduño-Espinosa, J; Campos-Leyva, M E; Fajardo-Gutiérrez, A ...
Boletín médico del Hospital Infantil de México (Spanish edition)
48, Številka:
11
Journal Article
Recenzirano
To identify the mortality prognostic factors from a pediatric intensive care unit.
Retrolective cohort study with an analysis of cases and controls (ambidirectional design). PLACE OF STUDY: The ...intensive care unit at a Pediatric Third Level Hospital.
All of the patients admitted into the I.C.U. for a year (August 1989 to August 1990).
The patients were identified when admitted into I.C.U., while evaluating their clinical course through their charts. Afterwards, they were placed into two groups, those who died while in I.C.U. (n = 49) and those in the control group which constituted the initial cohort survivors (n = 115). The prognostic factors evaluated were age, sex, diagnosis when admitted, organic failure, changes in diagnosis and treatment.
164 patients were studied, with a slight predominance of the male sex (53%). The patient's age fluctuated between 1 day and 17 years of age, with a mean age of 10 months. The diagnosis established when admitted were predominantly dealing with infectious problems (n = 54, 32%). The most important prognostic factors seen during the bivaried analysis were the peritoneal dialysis (RM = 12.71, IC 95% = 2.41-98.29, P less than 0.01); a Glasgow index less than or equal to 10 points (RM = 7.33, IC 95% = 1.25-47.26, P less than 0.01), respiratory organic failure (RM = 6.32, IC 95% = 2.46-16.8, P less than 0.01) and assisted mechanical ventilation (RM = 5.61, IC 95% = 2.52-12.68, P less than 0.01).
The mortality rate in I.C.U. was 30%. The most important prognostic factors associated to mortality after adjusting for severity were having a cardiovascular ailment, the need to administer blood products, a Glasgow index less than or equal to 10 points, heart and hematologic organic failure and when respiratory mechanical assistance was provided.
In clinical pediatric research as in all research, one of the fundamental characteristics is the measurement of the studied features, either clinical, of laboratory or cabinet. A measurement must ...have two fundamental characteristics, for it to be considered as scientific: consistency and validity. The first one is centered on the variability of the measurement, which is due to the measuring instrument, to the subject or entity which is measured and to the individual or individuals who carry out the measuring, this is known as intra or interobserver variability, respectively. Validity is the fact of "actually" measuring what we want to measure. Both characteristics of measurement, are often mixed, between them and with other concepts, and this is the reason of not having a clear idea of what is the real meaning. This paper discusses the different terms that have been used for consistency and validity of a measurement. Also it points out how to assess consistency, from the validity, taking into account the measuring scale of the variables and the number of observers. Easy examples are used for the application of different formulas and for the interpretation of the results.
There are different risk factors which have been related to the presence of leukemia in children. In the past years one of these factors has become relevant, the risk of living in an area near to ...high electric voltage lines, generators of electromagnetic fields of low frequency (EMF), which can cause development of leukemia in children.
To learn whether living in an area close to EMF generator sources, electric transformers, high electric voltage distribution or transmission lines and electric substations, is a risk factor in the development of leukemia in children living in Mexico City.
A projective study of case-control was accomplished. The cases were obtained from hospitals of the third level. The diagnosis of leukemia in its different varieties was confirmed through biopsy of bone marrow. The controls were selected in the same hospital from inpatients and outpatients with different problems, except neoplasia. A total sample of 81 cases and 77 controls was analyzed. The residence of the controls and cases were visited using a questionnaire coded with the different study variables. To diminish the memory bias in relation to EMF, the subjects were shown different pictures pointing out the different sources of exposures, which were asked. Having obtained the information, different odds ratios (OR) were calculated for the different associations, as well as the confidence intervals at 95% and an unconditioned logistic regression was accomplished to know the adjusted OR.
There were no differences between the cases and controls according to the relative who gave the information, the current age of children, the parents's age, the social class and the parent's occupation. It was found that all the generating sources of EMF, which were involved in the study, had and OR above 1. Being the highest, the ones living near the distribution or transmission wires of high voltage with an OR of 2.63 (1.26-5.36) and 2.5 (0.97-6.67) respectively. When the distance of exposure was controlled, the highest OR was for distribution lines (OR 2.12; 0.79-5.85). When the analysis was applied to persons who have moved from the residence, it was found that the OR was above 1 in all the associations, the highest being the distribution wires and with the distance the highest was the electric substations. Furthermore, the multivariate analysis showed that the risk continued only for the distribution wires.
The EMF exposure was found positive, however this is not very precise, that is why it is necessary to carry out other studies to confirm the existence of the association and correct possible biases which could appear during the research.
Leukemia is the most frequent neoplasia in children; in our country it is the main cause of medical attention in children with cancer. The are different risk factors associated with the development ...of this kind of cancer.
To identify which of the already known factors described in the literature associated with the development of leukemia are most frequent in the pediatric population of Mexico City.
A protective case-control study was carried out using prevalent and incident cases. In two third level hospitals of Mexico City, a total of 81 children who had been diagnosed as suffering from different kind of leukemia, confirmed by biopsy of bone marrow, were select and studied. The control were 154 children from two different sources: 77 of them came from the same hospital where the cases received medical care, the selection criteria was not to have any kind of neoplasia; and 77 came from the same community where those diagnosed children cases lived, the selection criteria for this group was that they were healthy children. Both cases and community controls were visited at home and interview to complete precoded questionnaire with the different variables of the study. The information from the hospital controls was obtained during the time they stayed in the hospital. Odds ratio (OR's) for the different associations were calculated, as well as its confidence intervals at 95% (IC) accord to Cornfield and unconditioned logistic regression was carried out to control confounding variables.
OR greater than 1 was found in those with familiar cancer background 1.93 (1.2-3.63); the mother being exposed to X-ray during pregnancy 1.89 (0.84-4.22); previous abortions before the child with leukemia was born 2.44 (1-06-5.68); being born from full term birth 2.42 (0.47-16.65); being born with weight greater that 3500 g 2.21 (1.04-4.33); being exposed to fertilizers 4.73 (1.04-24.14) and insecticides 1.93 (1.05-3.56). OR smaller than 1 was found in those who have been in a hospital because of an infectious disease during the first year of life 0.57 (0.17-1.74); to have suffered from chicken pox 0.59 (0.32-1.08). No association to parent's age or job was found. Multivariated analysis shows that the exposure to insecticide is the most important risk factor associated with the development of leukemia in children.
We obtained positive associations to different risk factors described in the literature, having found that exposure to fertilizers is the most important risk factor and finding no association with the parent's occupation. This leads to the need of carrying out further studies to investigate, in more detail, the occupation of the father to confirm whether or not this is a risk factor.
