Trade-offs between succulent and non-succulent epiphytes underlie variation in drought tolerance and avoidance.

Epiphyte communities comprise important components of many forest ecosystems in terms of biomass and diversity, but little is known regarding trade-offs that underlie diversity and structure in these communities or the impact that microclimate has on epiphyte trait allocation. We measured 22 functional traits in vascular epiphyte communities across six sites that span a microclimatic gradient in a tropical montane cloud forest region in Costa Rica. We quantified traits that relate to carbon and nitrogen allocation, gas exchange, water storage, and drought tolerance. Functional diversity was high in all but the lowest elevation site where drought likely limits the success of certain species with particular trait combinations. For most traits, variation was explained by relationships with other traits, rather than differences in microclimate across sites. Although there were significant differences in microclimate, epiphyte abundance, and diversity, we found substantial overlap in multivariate trait space across five of the sites. We found significant correlations between functional traits, many of which related to water storage (leaf water content, leaf thickness, hydrenchymal thickness), drought tolerance (turgor loss point), and carbon allocation (specific leaf area, leaf dry matter content). This suite of trait correlations suggests that the epiphyte community has evolved functional strategies along with a drought avoidance versus drought tolerance continuum where leaf succulence emerged as a pivotal overall trait.

A critical test of twelve methods for estimating age using radiographic staging of developing teeth on a sample of 6- to 15-year-old children from Mérida, Yucatán (México).

Cross-population applicability of osteological and dental methods is a known issue in forensic anthropology, but very little is known about whether differences between populations are due to ancestry, environment effects, or even the statistical approach utilized for developing the methods. This study wishes to add to the discussion of population-specificity of dental age estimation methods and examine the impact of their statistical basis on their accuracy and precision. These parameters were estimated by testing 12 different dental age estimation techniques on a sample of 182 panoramic radiographs of children between the ages of 6 and 15 years (110 girls and 72 boys) from the city of Mérida in Yucatán, México. None of the 12 methods selected is based on Mexican samples. Dental maturation was scored following and methods tested employed two dental scoring schemes: Moorrees, Fanning, and Hunt's (MFH) 13-/14-stage system and Demirjian's 8-stage system. Results show that methods derived from more geographically specific groups do not fare better or worse than methods developed on more diverse and inclusive international samples, even if no methods specific to Mexicans were tested. While some of the methods performed very well, and they were not based on a Mexican sample, this suggests that population-specific dental age estimation methods may be relatively unimportant or that population differences in dental maturation are very small. Other issues seemed to have a greater impact on accuracy and precision, such as age dependency, inclusion of the third molar in age assessments, age truncation and age heaping in reference samples, the dental scoring scheme used, and how predicted age is calculated mathematically. As such, findings in this study suggest that validation tests of age estimation methods may not be a useful or reliable means to assess population differences and that these differences need to be more systematically assessed if an argument is to be made for the increased accuracy and precision of population-specific methods. The statistical basis of dental prediction methods seems to have a more significant role in their accuracy and precision outside of their reference sample.

Prevention and treatment of upper respiratory diseases in the pandemic COVID-19 era.

In the pandemic coronavirus disease 2019 (COVID-19) era, the need to use preventive-curative treatments is compelling. A series of non-pharmacological compounds, including oligo-elements, vitamins, nutraceuticals, and bacteriotherapy, might affect the risk of COVID-19, both reinforcing the immune system and improving the inflammation resolution during respiratory infections. Non-pharmacological remedies are very popular and usually have no relevant side effects. Bacterial and natural products may potentiate the immune system against respiratory viruses. Moreover, these compounds also exert antiinflammatory and antioxidant activity. Consequently, these non-chemical remedies could be prescribed to build up the immune defence and adequately treat the upper respiratory infection. In this way, natural compounds could be used to manage people in the pandemic COVID-19 era.

Nasal eosinophilic angiocentric fibrosis with IgG4-positive plasma cell infiltration.

INTRODUCTION: Eosinophilic angiocentric fibrosis (EAF) is a rare lesion that predominantly affects the upper respiratory tract. Its etiology is unknown and it has been recently associated with the IgG4- related disease (IgG4-RD) spectrum. To the author's knowledge, this is the sixth case report of the relationship between EAF and IgG4-RD. CASE REPORT: We report the case of a 37-year-old woman with nasal deformity and facial pain. The lesion was surgically excised. Histological examination revealed features of EAF with an IgG4/IgG plasma cell ratio ≷73% and 31 IgG4 stained cells per high power field. No clinical or radiological recurrence was detected during follow-up. Serum IgG4 quantification one year after surgery was within normal limits. DISCUSSION: The relationship between both entities may have therapeutic impact because IgG4-RD of the head and neck has a high remission rate with corticosteroids and immunosuppressive therapy. Additional reports of this infrequent disease are necessary to elucidate appropriate treatment and prognosis.

Liver damage in bleomycin-induced pulmonary fibrosis in mice.

Pulmonary fibrosis is an emerging disease with a poor prognosis and high mortality rate that is even surpassing some types of cancer. This disease has been linked to the concomitant appearance of liver cirrhosis. Bleomycin-induced pulmonary fibrosis is a widely used mouse model that mimics the histopathological and biochemical features of human systemic sclerosis, an autoimmune disease that is associated with inflammation and expressed in several corporal systems as fibrosis or other alterations. To determine the effects on proliferation, redox and inflammation protein expression markers were analyzed by immunohistochemistry. Analyses showed a significant increase in protein oxidation levels by lipoperoxidation bio-products and in proliferation and inflammation processes. These phenomena were associated with the induction of the redox status in mice subjected to 100 U/kg bleomycin. These findings clearly show that the bleomycin model induces histopathological alterations in the liver and partially reproduces the complexity of systemic sclerosis. Our results using the bleomycin-induced pulmonary fibrosis model provide a protocol to investigate the mechanism underlying the molecular alteration found in the liver linked to systemic sclerosis.

Factores fisiopatológicos y metas terapéuticas perioperatorias que influyen en procedimientos quirúrgicos reconstructivos mediante colgajos en pacientes con Diabetes Mellitus / Pathophysiologic factors and perioperative therapeutic goals that affect reconstructive surgical procedures with flaps in patients with Diabetes Mellitus

RESUMEN Introducción: la diabetes mellitus es considerada un factor de riesgo para complicaciones locales y fracaso quirúrgico en cirugías reconstructivas mediante el uso de colgajos debido a las alteraciones en el proceso de cicatrización propias de esta patología. Objetivo: hacer una revisión de la literatura disponible sobre los factores fisiopatológicos que influyen en los resultados posquirúrgicos a corto, mediano y largo plazo en la población diabética, así como de las metas terapéuticas perioperatorias asociadas a mayores tasas de éxito. Metodología de Búsqueda: se realizó búsqueda en las bases de datos PUBMED, MEDLINE Y SCIELO, mediante el gestor de búsqueda utilizando los términos: "Period perioperative", "Reconstructive surgical procedures", "Surgical flaps", "Diabetes mellitus", obteniendo un total de 160 artículos de revistas en línea, de los cuales se seleccionaron 50. Resultados: la realización de colgajos en pacientes con diabetes mellitus se asocia a mayor riesgo de fracaso y complicaciones, las cuales disminuyen considerablemente si se realiza un estricto manejo perioperatorio enfocado en metas. Conclusiones: la diabetes mellitus causa alteraciones en la respuesta inflamatoria, disfunción microvascular y mayor estrés oxidativo, lo cual se ve reflejado en un proceso de cicatrizacion anormal, generando mayores tasas de infeccion y perdidas de colgajos; un estricto manejo peri operatorio guiado por metas logra disminuir las complicaciones y aumentar el exito quirurgico. MÉD.UIS. 2017;30(1):35-43.

ABSTRACT Introduction: diabetes mellitus is considered a risk factor for local complications and surgical failure in reconstructive surgeries, mainly in flaps due to the fact that it causes alterations in the cicatrization process. Objective: to review the available literature on the pathophysiological factors that influence the short-, medium- and long-term results in the diabetic population, the perioperative therapeutic goals associated with higher success rates, and to establish a baseline protocol for the perioperative management of these patients. Searching methodology: we searched the PUBMED, MEDLINE and SCIELO databases using the search terms "Period perioperative", "Reconstructive surgical procedures", "Surgical flaps", "Diabetes mellitus", obtaining a total of 160 online journal articles, of which 50 were selected. Results: the performance of flaps in patients with diabetes mellitus is associated with an increased risk of failure and complications, which decrease considerably when a strict goal-directed perioperative management is performed. Conclusions: diabetes mellitus causes alterations in the inflammatory response, microvascular dysfunction and increases oxidative stress, which is reflected in an abnormal healing process, generating higher infection rates and graft loss, but if glycemic management goals are achieved in the perioperative period it is possible to reduce the complications and to increase the surgical success. MÉD.UIS. 2017;30(1):35-43.

Parathyroid hormone response to two levels of vitamin D deficiency is associated with high risk of medical problems during hospitalization in patients with hip fracture.

BACKGROUND: Vitamin D and the parathyroid hormone (PTH) response play an important role in hip fracture patients. This study was carried out to determine the factors associated with the PTH response to different levels of vitamin D deficiency during hospitalization. METHODS: This was a cross-sectional study of patients over 64 years of age admitted with an acute fragility hip fracture between March 1st 2009 and November 30th 2012. Demographic, clinical, functional, and cognitive function were evaluated at admission and during hospitalization. Levels of 25-hydroxyvitamin D (25-OHD) and PTH were analyzed. Two 25-OHD cut-off points were considered, <12 ng/ml and 12-20 ng/ml. Multivariate logistic regression analysis was used. RESULTS: Mean age of the 607 patients included was 84.7 years (SD 7.10), and 81.9 % were women. The mean 25-OHD level in the total sample was 13.2 (SD 11.1) ng/ml. Levels of 25-OHD <12 ng/ml were present in 347 patients (57.2 %), of whom 158 (45.5 %) had secondary hyperparathyroidism (SHPT) (PTH >65 pg/ml). 25-OHD levels of 12-20 ng/ml were present in 168 (27.7 %) patients, of whom 47 (28 %) had SHPT. Following logistic regression, SHPT was associated in both groups (25-OHD <12 and 12-20 ng/ml) with a greater number of medical problems during hospitalization. In the 25-OHD group <12 ng/ml, SHPT was also associated with poorer glomerular filtration rates. CONCLUSION: The PTH response to vitamin D deficiency in hip fracture patients may be a marker for patients with higher risk of developing multiple medical problems, both when considering severe (<12 ng/ml) and moderate (12-20 ng/ml) vitamin D deficiency.

Insertion of exogenous epitopes in the E3-19K of oncolytic adenoviruses to enhance TAP-independent presentation and immunogenicity.

Oncolytic adenoviruses can promote immune responses against tumors by expressing and/or displaying tumor-associated antigens. However, the strong immunodominance of viral antigens mask responses against tumor epitopes. In addition, defects in major histocompatibility complex class I antigen presentation pathway such as the downregulation of the transporter-associated with antigen processing (TAP) are frequently associated with immune evasion of tumor cells. To promote the immunogenicity of exogenous epitopes in the context of an oncolytic adenovirus, we have taken advantage of the ER localization of the viral protein E3-19K. We have inserted tumor-associated epitopes after the N-terminal signal sequence for membrane insertion of this protein and flanked them with linkers cleavable by the protease furin to facilitate their TAP-independent presentation. This strategy allowed an enhanced presentation of the exogenous epitopes in TAP-deficient tumor cells in vitro and the generation of higher specific immune responses in vivo that were able to significantly control tumor growth.

The association between CDC42 and caveolin-1 is involved in the regulation of capacitation and acrosome reaction of guinea pig and mouse sperm.

In the mammalian sperm, the acrosome reaction (AR) is considered to be a regulated secretion that is an essential requirement for physiological fertilization. The AR is the all-or-nothing secretion system that allows for multiple membrane fusion events. It is a Ca(2)(+)-regulated exocytosis reaction that has also been shown to be regulated by several signaling pathways. CDC42 has a central role in the regulated exocytosis through the activation of SNARE proteins and actin polymerization. Furthermore, the lipid raft protein caveolin-1 (CAV1) functions as a scaffold and guanine nucleotide dissociation inhibitor protein for CDC42, which is inactivated when associated with CAV1. CDC42 and other RHO proteins have been shown to localize in the acrosome region of mammalian sperm; however, their relationship with the AR is unknown. Here, we present the first evidence that CDC42 and CAV1 could be involved in the regulation of capacitation and the AR. Our findings show that CDC42 is activated early during capacitation, reaching an activation maximum after 20 min of capacitation. Spontaneous and progesterone-induced ARs were inhibited when sperm were capacitated in presence of secramine A, a specific CDC42 inhibitor. CAV1 and CDC42 were co-immunoprecipitated from the membranes of noncapacitated sperm; this association was reduced in capacitated sperm, and our data suggest that the phosphorylation (Tyr14) of CAV1 by c-Src is involved in such reductions. We suggest that CDC42 activation is favored by the disruption of the CAV1-CDC42 interaction, allowing for its participation in the regulation of capacitation and the AR.

Improved systemic antitumor therapy with oncolytic adenoviruses by replacing the fiber shaft HSG-binding domain with RGD.

Retargeting oncolytic adenoviruses from their systemic preeminent liver tropism to disseminated tumor foci would highly improve the efficacy of these agents at eradicating tumors. We have replaced the KKTK fiber shaft heparan sulfate glycosaminoglycan-binding domain with an RGDK motif in order to achieve simultaneously liver detargeting and tumor targeting. When inserted into a wild-type backbone, this mutation palliated liver transaminase elevation and hematological alterations in mice. Importantly, when tested in a backbone that redirects E1A transcription towards pRB pathway deregulation, RGD at this novel shaft location also improved significantly systemic antitumor therapy compared with the broadly used RGD location at the HI-loop of the fiber knob domain.

Grado de control de la presión arterial en pacientes crónicos de Atención Primaria / Blood pressure control in a hypertensive population in a primary care centre

Objetivos. Conocer el grado de control de la PA y las estrategias terapéuticas en pacientes hipertensos. Material y métodos. Estudio analítico transversal, sobre 229 pacientes hipertensos de la consulta de 2009. Se registraron las variables: edad, sexo, HTA, diabetes mellitus, lesiones de órganos diana, además de realizar un ECG y análisis de sangre y orina. La medida de PA se realizó siguiendo normas estandarizadas y se calculó la media aritmética de 2 tomas sucesivas. Se consideró que había buen control cuando el promedio era inferior a 140/90 en general, y menor de 130/80mmHg en pacientes con diabetes, insuficiencia renal o enfermedad cardiovascular. Resultados. El 56,77% eran mujeres con una edad media de 70,29±1,56 años. El 41,92% de los pacientes y el 23,61% de los diabéticos presentaban buen control de PA, siendo peor a mayor edad (33,33% en mayores de 85 años), p=0,0013; y mayor RCV (33,33%), p=0,004. Se realizaron cambios terapéuticos en el 57,14% de los casos con mal control. Los ARA-II fueron los fármacos más empleados (66,27%) y los diuréticos en las combinaciones (88,24%). El análisis multivariante mostró que el mal control metabólico de DM influía en el mal control de PA (R=0,15; p=0,01). Conclusiones. El control de las cifras de PA en nuestro centro de AP es peor en pacientes diabéticos. El control de la PAS es peor a mayor edad y mayor RCV. Los ARA-II y diuréticos son los fármacos más empleados en el tratamiento de la HTA. El mal control metabólico de la DM es la variable que más influye en el control de la PA (AU)

Objectives. To find out the level of BP control and therapeutic strategies in hypertensive patients. Material and methods. Cross-sectional study on 229 hypertensive patients seen in 2009. Variables were recorded: age, sex, hypertension, diabetes mellitus, target organ damage, as well as an ECG and blood and urine tests. The BP measurement was performed following a standard protocol and the arithmetic mean of two successive measurements was calculated. It was assumed that there was good control when the mean was less than 140/90 in general, and less than 130/80mmHg in patients with diabetes, renal or cardiovascular disease. Results. There were 56.77% women, with a mean age of 70.29±1.56 years. Good BP control was observed in 41.92% of patients and 23.61% of the diabetics, being worse with increasing age (33.33% older than 85 years), p=0.0013, and increased cardiovascular risk (33.33%), p=0.004. Therapeutic changes were made in 57.14% of cases with poor control. ARA-II drugs were used (66.27%) and diuretics in combination (88.24%). Multivariate analysis showed that poor metabolic control of DM affected the poor control of BP (R=0.15, p=0.01). Conclusions. The control of BP values at our centre is worse in diabetic patients. The control of the BP is worse with increasing age and greater cardiovascular risk. ARA-II and diuretics are the drugs most used in the treatment of hypertension. Poor metabolic control of DM is the most influential variable in the control of the BP (AU)

Social capital and self-rated health in urban low income neighbourhoods in Chile.

OBJECTIVE: To examine the potential association between social capital and self-rated health within a low income community of Santiago, Chile. METHOD: Cross-sectional survey, based on in-home interviews in the municipality of Puente Alto in Santiago, Chile. The participants were 781 residents of four neighbourhoods within Puente Alto (mean age 45.5 years). RESULTS: Principal components analysis with varimax rotation identified five domains of social capital: perceived trust in neighbours, perceived trust in organisations, reciprocity within the neighbourhood, neighbourhood integration, and social participation (Cronbach alphas: 0.58 to 0.77). Trust and reciprocity were significantly associated with better self-rated health. For example, a one standard deviation increase in trust in neighbours was associated with an adjusted odds ratio of 1.10 (95% confidence interval, CI: 1.05 to 1.15) for reporting good self-rated health. By contrast, social participation was associated with a lower odds (0.89, 95% CI: 0.89 to 1.06) of reporting good health. CONCLUSION: Neighbourhood social cohesion, measured by trust and reciprocity, is associated with higher self-rated health. However, social participation did not appear to be associated with better health in this predominantly low income neighbourhood. These findings provide preliminary support to the relevance for social capital as a determinant of health in Chile.

Parámetros cinéticos de crecimiento de saccharomyces cerevisiae en presencia de un campo magnético variable de baja intensidad y alta frecuencia / Kinetic parameters of growth of saccharomyces cerevisiae affected by a varying magnetic field of low intensity and high frequency

En el presente trabajo se evalúa el crecimiento de la levadura Saccharomyces cerevisiae en malaza (miel virgen), en presencia de un campo magnético (CM) variable de alta frecuencia y baja intensidad. Se evalúan los parámetros cinéticos: Velocidad específica máxima de crecimiento (?max), constante de saturación (Ks) y coeficiente de rendimiento (Yxs). Se realizan ensayos en fermentadores de 400 ml, a temperatura de 25 º C. El flujo de aire utilizado en cada fermentador es de aproximadamente 1 vvm. El campo aplicado posee una frecuencia de 100 kHz, el tiempo de exposición es de 200 s y la densidad de campo usada es de 250 mG. Se comparan los resultados obtenidos para cultivos bajo la acción del CM y cultivos creciendo en condiciones ambientales normales (control). Los resultados muestran que el campo magnético puede afectar los parámetros cinéticos de forma diferente dependiendo del número de aplicaciones que se utilicen, llegando a generar incrementos de hasta 20 (por ciento) en la velocidad específica de crecimiento y de hasta el 28 (por ciento) en el rendimiento, y descensos de hasta el 26 (por ciento) en el valor de la constante de saturación

Effects of mining activities on heavy metal concentrations in water, sediment, and macroinvertebrates in different reaches of the Pilcomayo River, South America.

From 1997 until 1999 the extent and the ecological effects of zinc, copper, lead, and cadmium pollution were studied in different reaches of the South American Pilcomayo River. A comparison of metal concentrations in water, sediment, and chironomid larvae, as well as the diversity of macroinvertebrate species, was made between sites near the origin of the Pilcomayo River, with hardly any mining activities, sites in the Potosí region, with intensive mining, and sites located 500 km or further downstream of Potosí, in the Chaco plain. Samples were also collected in an unpolluted river (Cachi Mayu River) and in the Tarapaya River, which is strongly contaminated by mine tailings (1000 tons a day). The upper parts of the Pilcomayo River are strongly affected by the release of mine tailings from the Potosí mines where mean concentrations of lead, cadmium, copper, and zinc in water, filtered water, sediment, and chironomid larvae were up to a thousand times higher than the local background levels. The diversity of the benthic macroinvertebrate community was strongly reduced in the contaminated parts; 97% of the benthic macroinvertebrates consisted of chironomid larvae. The degree of contamination in the lower reaches of the river, however, was fairly low because of sedimentation processes and the strong dilution of mine tailings with enormous amounts of clean sediment from erosion processes. Analysis of sediment cores from the Ibibobo floodplain, however, reveal an increase of the heavy metal concentrations in the lower reaches since the introduction of the contaminating flotation process in the mine industry in 1985.

[Socioeconomic strata as a predictor factor for constant condom use among adolescents]. / El estrato socioeconómico como factor predictor del uso constante de condón en adolescentes.

INTRODUCTION: Socioeconomic level plays an important role in health inequalities. In Mexico, the highest prevalence of AIDS cases is among individuals of lower socioeconomic level. The purpose of the study was to describe the socioeconomic level (adjusted for psychosocial, situational and demographic variables) as a predictor factor for the consistent condom use among adolescents of Guadalajara, Mexico. METHODS: A sample of 1,410 adolescents, aged 15 to 19 years, drawn from a previous survey stratified by age, gender and socioeconomic strata was included in the study. Analysis was performed in 251 adolescents who reported sexual activity. Statistical analysis was performed using Chi-square, t-test, ANOVA, and logistic regression. RESULTS: The frequency of consistent condom use was 30.7% and there was a prevalence of irregular use. The highest social level was the main predictor (OR= 11.1, CI 95%=2.6-47.6). Others significant predictors were male gender, peer support and better knowledge about HIV/AIDS. CONCLUSION: Socioeconomic level is an important predictor factor for consistent condom use.

[Sources of information and their relationship to the degree of knowledge about AIDS in Mexican adolescents]. / Fuentes de información y su relación con el grado de conocimientos sobre el SIDA en adolescentes de México.

INTRODUCTION: In Mexico 2.1% of the cases of AIDS are in adolescents. The cases of AIDS in the age group of 20 to 29 account for 30.5% of all the cases and an important proportion could have been infected with HIV in their adolescence, in view of the length of the incubation period from the infection with HIV to the manifestation of the syndrome. The adolescent's knowledge of HIV/AIDS varies. In some urban contexts the adolescents have lay concepts and myths that could guide them into misting practices that could lead to contamination by HIV. The mass media, especially television, and interpersonal sources such as teachers, parents and peers are important sources of information about HIV/AIDS and have a central role in the social construction and public perception of the problem in adolescents. The objective of the study is to relate the degree of knowledge of HIV/AIDS to the exposure to information sources among adolescents in Guadalajara city, in Mexico. MATERIAL AND METHOD: Survey sample with autoapplied questionnaire. Sample of 1,410 adolescents, male and female, of 15 to 19 years of age, in the four socioeconomic strata. The Chi-square and BTukey tests, 95% confidence interval for proportions and means, and simple ANOVA factor were applied. RESULTS: A considerate degree of knowledge (mean of 13.94 correct answer out of 24, standard deviation = 4.09, 95% CI = 13.69-14.11) was found significant mean differences in favor of the high (15.70) and medium (14.26) strata as opposed to the low (13.51) and marginalized (12.85) (F = 19.39, p < .0001, BTukey level .050). The information published by the newspapers (F = 11.1; p < .001) and the teachers (F = 3.72; p < .05) had a direct relationship to the degree of knowledge imported by the daily exposure to the television and other social demographic variables. CONCLUSIONS: The results describe the presence of inequalities by socioeconomic strata in the list of sources in information and the levels of knowledge about HIV/AIDS. It is necessary to strengthen and develop educational action and the publication of messages through the media, institutions and interpersonal networks, with emphasis on interpersonal and media sources available to the low and marginalized strata, and at the same time, to strengthen the action of sources of information available to the other socioeconomic strata.

PIP: 1410 adolescents aged 15-19 years, of both sexes and of varying socioeconomic strata in Guadalajara, completed anonymous self-administered questionnaires concerning their sources of information and knowledge of HIV/AIDS. The objective was to determine the relation between sources of information and degree of knowledge to guide future information campaigns. 95% of the adolescents knew about AIDS. 79% received information from television, 39% from radio, 26% from magazines, and 16% from newspapers. The media identified as the most important sources of information on AIDS were television (60%), and newspapers and magazines (25% each). Except for television, access to the mass media was greater in the high and medium socioeconomic strata. Interpersonal sources of information on HIV/AIDS included teachers for 39%, family members for 38%, friends for 32%, and physicians for 26%. Access to information through interpersonal means was always higher in higher strata. The adolescents had a fair degree of knowledge of AIDS, averaging 13.9 correct answers out of 24 questions. The average numbers correct were 15.7 in the high, 14.3 in the medium, 13.5 in the low, and 12.9 in the marginal strata. Analysis of variance demonstrated that newspapers were the only mass source of information presenting direct positive relation with level of knowledge. Among interpersonal relations, information from teachers had the greatest positive association with level of knowledge.

[Sexual subcultures and degree of risk for acquiring HIV in adolescents in a marginal neighborhood]. / Subculturas sexuales y grado de riesgo de adquisición del VIH en adolescentes de un barrio marginado.

OBJECTIVE: To describe the sexual subcultures and the risk of acquiring HIV among adolescents in Guadalajara, Jalisco MATERIAL AND METHODS: The study took place during August 1994. A cross-sectional study design was used; data collection was done using pile sorts of 20 males and 20 females aged between 15 and 19 years. Data analysis was done by means of hierarchical clustering, multidimensional scaling, cultural consensus and correspondence techniques. RESULTS: Males: this cluster presented a sexual subculture pattern of free expression associated to high risk behaviors. Females: this cluster showed a sexual subculture pattern of celibacy, associated to low risk. Correspondence analysis: a correlation was found among adolescents between their sexual subcultures and risk of acquiring HIV. CONCLUSIONS: Among males, the free expression sexual subculture included high risk sexual behavior for acquiring HIV. Among females, the celibacy sexual subculture included low risk sexual behavior. Nevertheless, both males and females presented high risk sexual behaviors, since they engage in unprotected sexual practices.

[Malnutrition as a multiple cause of death]. / El análisis de la desnutrición como causa múltiple de muerte.

With the purpose of describing the role of malnutrition at death time, an analysis of multiple causes of death in children under five years-old was performed on deaths which occurred during April and May 1985 in Mexico City. A proportional mortality analysis was done taking in consideration all the causes listed on the death certificate, not only the underlying causes. The number of deaths associated to malnutrition was greater by multiple cause than by underlying cause (OR = 7.9, 95% CI 5.0-12.7, p = 0.00000). The importance of considering multiple causes of death, mainly when there are frequent diseases which are some times recorded as underlying cause of death, is also discussed.

[Analysis of multiple-cause mortality: a new approach]. / El análisis de la mortalidad por causa múltiple: un nuevo enfoque.

Due to changes in mortality patterns, cronic and degenerative diseases have become a major problem in Mexico. Description and explanation of this kind of deaths is difficult by means of a single cause of death. In order to have a better understanding of this fenomenum an analysis of 4021 deaths occurred in Mexico city during april and may in 1985 using multiple cause of death was performed, this analysis take count of all causes reported in death certificates. With the method of multiple cause we found that the number of associated deaths, for example with hypertension and nutritional deficiencies, was considerably greater that when reported as underlying cause.