Biomedical subjects
Publications and source records attributed to S Parra.
It is fundamental that quality, incorporated as a service, be provided. Assessing employees' input through a survey is an essential process. By developing, implementing and responding to staff questionnaires, a facility shows commitment to quality improvement. The mission and philosophy of a facility needs to incorporate employees concerns, and utilize this information towards the goal of improved patient care.
We describe sharply localized attenuated areas in the alveolar walls of 17 of 25 human specimens. In these areas the connective tissue scaffolding of the alveolar septum was interrupted, and the thickness of the alveolar wall was reduced to that of a single or double layer of alveolar epithelium, devoid of basal laminae. Serial sections proved that most such gaps were bridged by a thin partition of intact epithelium continuous with Type I cells at the borders of the gap. These areas were observed infrequently during a systematic ultrastructural survey of specimens from grossly normal areas of lung tissue obtained at surgery or at autopsy. The mean diameter of 25 gaps bridged by a double layer of epithelium was 4.1 +/- 2.0 micrometers, whereas that of 49 gaps bridged by a single layer of epithelium was 5.0 +/- 1.9 micrometers. This contrasted with the mean diameter of 329 interalveolar pores, which was 6.5 +/- 2.4 micrometers (p less than 0.01). The number of profiles of epithelial partitions per centimeter of section profiles of interalveolar septums examined correlated directly with the number of pore profiles (p less than 0.003). This correlation, and the stepwise increase in size of gaps beginning with those bridged by 2 layers of epithelium and moving to those with only a single layer and finally to interalveolar pores, suggests that the epithelium-covered gaps are a transitional stage in the development of pores. This hypothesis is strengthened by the rare occurrence of epithelium-covered gaps in which the epithelial partition is itself interrupted.
Electron microscopic examination of dog lungs after exposure to papain for as little as 30 min showed removal of surfactant material from the pores of Kohn, and significant enlargement of the pores. We analyzed these early events in terms of structural mechanics, and concluded that: (1) The approximate doubling of the average diameter indicates a lowering of the effective modulus of elasticity in the vicinity of the pores to less than 50% of its original value, which is consistent with the destruction of elastin. (2) The removal of the surfactant material, which normally occludes the pores, results in the loss of the force caused by surface tension, which normally acts at the rim of the pore, and alleviates maximal tissue stress. This lost force can result in a stress increase on the elastin by as much as 20 to 30% of its strength. (3) The whole lung volume pressure deflation curves obtained in hamsters after exposure to papain show a significant increase in compliance associated with papain treatment. Degradation in the elastic modulus of the tissue, caused by the papain, contributes to such an increase. On the other hand, surface tension measurements from canine lung extracts after exposure to papain yield results that should contribute to a decrease in compliance. Because papain treatment destroys the continuity of the lining layer, this contribution is minimized, and the effect on the tissue dominates, resulting in a net increase in compliance.
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BACKGROUND: In order to assess intake of antioxidants and retinol, we evaluated the validity and reproducibility of a semiquantitative food frequency questionnaire. METHODS: Data were collected from 110 women, aged 15-54 years, who resided in the southern part of Mexico City. Study participants were asked to complete the food frequency questionnaire before and after completing four series of 4 days of 24-h diet recalls. We obtained the 24-h recalls at 3-month intervals designed to account for seasonal variability. In addition, we measured serum blood levels of retinol and various carotenoids at 3 and 9 months after baseline. RESULTS: Intraclass correlation coefficients for intake of energy-adjusted daily nutrients, assessed by the questionnaires 1 year apart, ranged from 0.23 for lutein/zeaxanthin to 0.50 for total carotenes. Correlation coefficients between energy-adjusted nutrient intakes were measured by means of the sixteen 24-h dietary recalls, and the second questionnaire ranged from 0.09 for lutein/zeaxanthin to 0.45 for total carotenes. These correlations were higher after adjusting for day-to-day variations in diets ranging from 0.11 for lutein/zeaxanthin to 0.49 for vitamin C. Correlation coefficients between intake and biochemical measures were 0.32 for alpha-carotene, 0.34 for beta-carotene, and 0.40 for total carotene after adjusting for age, body mass index, cholesterol and triglyceride plasma levels, smoking status, and caloric intake. CONCLUSIONS: These data support the ability of our food frequency questionnaire to provide valid information on the relative intake of these nutrients and to confirm its usefulness in epidemiological studies of diet-disease relations. However, its application outside Mexico City or in different age or gender populations will require additional modifications and validation efforts.
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OBJECTIVE: To assess the reproducibility and validity of a 116 item semi-quantitative food frequency questionnaire (FFQ), designed to assess the relation between dietary intake and chronic diseases. MATERIAL AND METHODS: To test the reproducibility of the FFQ questionnaire, the FFQ was administered twice to 134 women residing in Mexico City at an interval of approximately one year; to assess the validity we compared results obtained by the FFQs with those obtained by four 4-day 24-hour recalls at three month intervals. Validity and reproducibility were evaluated using regression analysis and Pearson and intraclass correlation coefficients of log-e and calorie-adjusted nutrient scores. RESULTS: Mean values for intake of most nutrients assessed by the two food frequency questionnaires were similar. However, means for the 24-hr recall were significantly lower. Intraclass correlation coefficients for nutrient intakes, assessed by questionnaires, administered one year apart, ranged from 0.38 for cholesterol to 0.54 for crude fiber. Correlation coefficients between energy-adjusted nutrient intakes, measured by diet recalls, and the first FFQ ranged from 0.12 for polyunsaturated fatty acids to 0.67 for saturated fatty acids. Regression coefficients between 24-hr recall and FFQ,s were all significant were significant for all nutrients, except for polyunsaturated fat, folic acid, vitamin E and Zinc. CONCLUSIONS: These data indicate that this semi-quantitative FFQ is reproducible and provides a useful estimate by which to categorize individuals by level of past nutrient intake. However, its application outside Mexico City or in different age and gender populations will require additional modifications and validation efforts.
OBJECTIVE: To investigate some immune component that could contribute to the pathogenesis of Alzheimer's disease associated with the E280A mutation of the presenilin-1 gene (PS-1). PATIENTS AND METHODS: Serum antibodies against both cardiolipin and beta-amyloid peptides (beta 1-40 and beta 1-42) were quantitated by means of an indirect ELISA technique in carriers of the mutation, either healthy or with Alzheimer's disease, as well as in normal controls without the mutation. RESULTS: Out of 19 patients with Alzheimer's disease only 2 had increased values of antibodies to cardiolipin, namely: one with 14.58 micrograms/ml of IgM and the other with 36.16 micrograms/ml of IgG. The remaining individuals revealed values under 10 micrograms/ml, considered normal, and there was no significant difference between the groups. Significant serum reactivity (p < 0.001) was detected against both beta-amyloid peptides in the mutation carriers, either with or without Alzheimer's disease, as compared to the control group. No correlation was detected between this antibody response and the mental or functional situation of the patients. CONCLUSION: beta-amyloid antibodies, present in the mutation carriers, may simply represent a marker of immune activation induced by beta-amyloid with no in vivo effect; however, despite the results, the possibility can not be ruled out of a pathogenic role of these antibodies in early onset Alzheimer's disease.
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OBJECTIVE: This study evaluated the reproducibility of a questionnaire concerned with the clinical and epidemiological aspects of menopause. MATERIAL AND METHODS: The study population consisted of a hundred perimenopausal Mexican women seeking care at gynecology and obstetric health care services. Their participation was voluntary and they answered the same questionnaire two times with a 15-30 day lag between each application. RESULTS: The Kappa coefficient was high (0.81-1.0) for categorical variables such as: type of menstrual cycles, type of menopause, breast-feeding, use of estrogen during menopause and use of hormonal contraceptives. The Kappa coefficient was moderate (0.7-0.8) for symptoms related to menopause such as hot flashes, sweating, painful coitus, vaginal dryness and a decrease in libido. Mean differences were calculated for continuous variables such as age at menarche, age at menopause, time using estrogen and the duration of breast-feeding, the majority had a value of zero and 95% confidence intervals for these mean differences included the null value. The questionnaire also included other characteristics such as tobacco consumption and a short food frequency questionnaire, which showed high concordance (Kappa 0.7-1.0). CONCLUSIONS: The results of this study show that this questionnaire has a high level of reproducibility and can be useful as a research tool to explore menopause in Mexican women.