The impacts of seasonal variation and climate on food utilization in a population of critically endangered cotton-top tamarins (Saguinus oedipus) in Colombia: A 22-year longitudinal study.

To examine how precipitation patterns and climate change impact feeding choices made by a population of critically endangered cotton-top tamarins (Saguinus oedipus), we examined 22 years of feeding data (1999-2020) from 21 groups collected at Parque Natural Regional Bosque Seco El Ceibal Mono Tití in Santa Catalina, Colombia. We describe the diet and examine the role of seasonal rainfall and annual variation in rainfall on diet. Rainfall is highly seasonal (mean annual rainfall 1562 mm [range 940-2680 mm]) with a dry, early rainy, and late rainy season in each year. Over 80 species of plants formed part of the fruit, nectar, and exudate components of the diet. Fruits, although available year-round, were more commonly available and consumed during the late rainy seasons (August-November). Exudates were consumed more frequently in the dry season (December-March) and invertebrate consumption was stable across the year. Nectar feeding from a single species (Combretum fruticosum) peaked in November. Rainfall varied over the years, with 13 years exceeding the 99% confidence intervals for mean rainfall. Ten of these extreme years (both drought and extremely wet) occurred in the last 11 years. Fruit consumption did not vary between extreme and average years, but cotton-top tamarins consumed more invertebrates and exudates in wet years. Presently, cotton-top tamarins appear to be able to cope with these extreme variations in rainfall due to their highly varied diet. However, the forests that these primates depend upon for survival are threatened by human exploitation making it critically important to maintain a generalist feeding strategy for survival as many fruiting trees that compose a large proportion of the diet are removed. As conservation efforts continue, plant species consumed by cotton-top tamarins provide useful data when selecting species for habitat restoration programs.

Volumetric assessment of the sella turcica: a re-evaluation.

BACKGROUND: The sella turcica volume is widely measured by the Di Chiro-Nelson method. The purpose is to compare the fidelity of a proposed volumetry method vs. the Di Chiro-Nelson method, using computed tomography (CT) images. MATERIALS AND METHODS: Morphometric examination of 173 CT scans were included, of which 52.6% were female. The mean age was 53.2 ± 17.6 years. Considering the Di Chiro-Nelson method, two measurements were added for each axis in the CT evaluation: length (central, left, and right), width (central, anterior, and posterior), and height (central, left, and right). RESULTS: The mean measurements were length: central 10.11 ± 1.44, left 7.45 ± 1.67, right 7.53 ± 1.59; width: central 12.27 ± 2.11, anterior 10.99 ± 1.92, posterior 10.10 ± 1.74; height: central 7.68 ± 1.38, left 7.16 ± 1.35, right 7.40 ± 1.41. A statistically significant difference between sexes was found only in the anterior width (p = 0.01). Using the proposed method, the volume was 342.2 ± 88.5 and 378. 6 ± 113.9 mm³, respectively for females and males (p = 0.02) vs. 476.1 ± 132.4 and 523.8 ± 186.0 mm3 (p = 0.05) using the Di Chiro-Nelson's method. CONCLUSIONS: Women had significantly smaller sella turcica volume than men. This proposed method considers the sella turcica as a not strictly symmetrical structure and indicates reduced variation between the maximum and minimum values, compared to the Di Chiro-Nelson's. Our findings may be useful for reassessment the volume of the sella turcica as the measurements indicate a higher precision.

The influence of high-density lipoprotein (HDL) and HDL subfractions on insulin secretion and cholesterol efflux in pancreatic derived ß-cells.

BACKGROUND: High-density lipoprotein (HDL) is considered a complex plasma-circulating particle with subfractions that vary in function, size, and chemical composition. We sought to test the effects of HDL, and HDL subfractions on insulin secretion and cholesterol efflux in the ß-cell line MIN-6. METHODS: We used total HDL and HDL subfractions 2a, 2b, 3a, 3b, and 3c, isolated from human plasma, to test insulin secretion under different glucose concentrations as well as insulin content and cholesterol efflux in the insulinoma MIN-6 cell line. RESULTS: Incubation of MIN-6 cells with low glucose and total HDL increased insulin release two-fold. Meanwhile, when high glucose and HDL were used, insulin release increased more than five times. HDL subfractions 2a, 2b, 3a, 3b, and 3c elicited higher insulin secretion and cholesterol efflux than their respective controls, at both low and high glucose concentrations. The insulin content of the MIN-6 cells incubated with low glucose and any of the five HDL subclasses had a modest reduction compared with their controls. However, there were no statistically significant differences between each HDL subfraction on their capacity of eliciting insulin secretion, insulin content, or cholesterol efflux. CONCLUSIONS: HDL can trigger insulin secretion under low, normal, and high glucose conditions. We found that all HDL subfractions exhibit very similar capacity to increase insulin secretion and cholesterol efflux. This is the first report demonstrating that HDL subfractions act both as insulin secretagogues (under low glucose) and insulin secretion enhancers (under high glucose) in the MIN-6 cell line.

The -514C>T polymorphism in the LIPC gene modifies type 2 diabetes risk through modulation of HDL-cholesterol levels in Mexicans.

PURPOSE: Both type 2 diabetes (T2D) and low levels of high-density lipoprotein cholesterol (HDL-C) are very prevalent conditions among Mexicans. Genetic variants in the LIPC gene have been associated with both conditions. This study aimed to evaluate the association of the -514C < T (rs1800588) LIPC gene polymorphism with different metabolic traits, particularly the effects of this polymorphism on HDL-C plasma levels and T2D risk. METHODS: Mediation analysis was used to assess the direct and indirect effects of the -514C>T LIPC gene variant on HDL-C levels, T2D risk, and body mass index (BMI), in 2105 Mexican mestizo participants. We also assessed the functional effect of the -514C>T LIPC variant on the promoter activity of a reporter gene in the HepG2 cell line. RESULTS: Direct effects show that the -514C>T LIPC polymorphism is significantly associated with increased HDL-C plasma levels (ß = 0.03; p < 0.001). The -514C>T variant resulted in an indirect protective effect on T2D risk through increasing HDL-C levels (ß = - 0.03; p < 0.001). Marginal direct association between -514C>T and T2D was found (ß = 0.08; p = 0.06). Variables directly influencing T2D status were European ethnicity (ß = - 7.20; p < 0.001), age (ß = 0.04; p < 0.001), gender (ß = - 0.15; p = 0.017) and HDL-C (ß = - 1.07; p < 0.001). In addition, we found that the -514C>T variant decreases the activity of LIPC promoter by 90% (p < 0.001). CONCLUSIONS: The -514C>T polymorphism was not directly associated with T2D risk. HDL-C acts as a mediator between -514C>T LIPC gene variant and T2D risk in the Mexican population.

Microfiltración apical entre tres cementos utilizados en obturación retrógrada / Apical microfiltration between three cements used in retrograde obturation

Objetivo: Determinar la microfiltración apical de tres cementos utilizados en obturación retrógrada. Métodos: 45 piezas unirradiculares estandarizadas a 16 mm de longitud se instrumentaron con sistema ProTaper ® manual e irrigaron con NaClO al 5,25%. Las muestras fueron obturadas con cono principal ProTaper ® F3 y accesorios Denstply ® #A y #B; se realizó la recesión apical de 3 mm, posteriormente se desobturó 3 mm con ultrasonido (Satelec Acteon) con punta s12/70D; se dividió la muestra en tres grupos para realizar obturación retrógrada con diferentes cementos de obturación cada uno. Las muestras se incubaron a 37 °C por 3 días; se cubrieron con barniz de uñas excepto 2 mm apicales para ser sumergidas en azul de metileno al 1% por 48 horas, se lavaron y reali- zaron un corte longitudinal con disco de diamante #2 para su análisis en el estereomi- croscopio (EduBlue ED 1402S), con la ayuda de un micrómetro (Stainless Hardened) se obtuvieron diferentes valores de cada grupo, mismos que fueron analizados por medio de la comparación de medias y pruebas paramétricas. Resultados: La valoración media de la microfiltración que produce la obturación retrógrada indica que: el MTA ® presentó un valor de 87,33 ± 9,61 µm (14,57%), seguido del Biodentine ® con 136 ± 12,42 µm (22,69%), con respecto al IRM ® con mayor cantidad de microfiltración con un valor de 376 ± 12,98 µm (62,74%). Conclusiones: Al comparar las medias y porcentajes de la microfiltración apical que presentan los cementos IRM ® , Biodentine ® y MTA ® , se evidenció que el MTA ® presentó el menor valor de microfiltración

Objective: To determine the apical microfiltration of three cements used in retrograde obturation. Methods: 45 monoradicular pieces standardized to 16 mm in length were instrumented with manual ProTaper ® system and irrigated with 5.25% NaClO. The samples were sealed with ProTaper ® F3 main cone and Denstply ® accessories #A and #B; an apical recession of 3 mm was performed, subsequently a 3 mm of obturation was removed with ultrasound (Satelec Acteon) using tip s12/70D; the samples were divided into three groups to perform retrograde filling, each with different sealing cements. The samples were incubated at 37°C for 3 days; then covered with nail varnish except 2 mm apical to be immersed in 1% methylene blue for 48 hours, washed and longitudinally cut with #2 diamond disc for analysis in the stereo microscope (EduBlue ED 1402S), with the help of a micrometer (Stainless Hardened); different values of each group were obtained, then analyzed through comparison of means and parametric tests. Results: The average evaluation of the microfiltration produced by the retrograde filling indicates that: the MTA ® presented a value of 87.33 ± 9.61 µm (14.57%), followed by the Bio- dentine ® with 136 ± 12.42 µm ( 22.69%), compared to the IRM ® with the highest amount of microfiltration with a value of 376 ± 12.98 µm (62.74%). Conclusions: When comparing the means and percentages of the apical microfiltration of the IRM ® , Biodentine ® and MTA ® cements; it was evident that the MTA ® showed the lowest microfiltration value.

Genetic divergence predicts reproductive isolation in damselflies.

Reproductive isolation is the defining characteristic of a biological species, and a common, but often untested prediction is a positive correlation between reproductive isolation and genetic divergence. Here, we test for this correlation in odonates, an order characterized by strong sexual selection. First, we measure reproductive isolation and genetic divergence in eight damselfly genera (30 species pairs) and test for a positive correlation. Second, we estimate the genetic threshold preventing hybrid formation and empirically test this threshold using wild populations of species within the Ischnura genus. Our results indicate a positive and strong correlation between reproductive isolation and genetic distance using both mitochondrial and nuclear genes cytochrome oxidase II (COII: r = 0.781 and 18S-28S: r = 0.658). Hybridization thresholds range from -0.43 to 1.78% for COII and -0.052-0.71% for 18S-28S, and both F1 -hybrids and backcrosses were detected in wild populations of two pairs of Ischnura species with overlapping thresholds. Our study suggests that threshold values are suitable to identify species prone to hybridization and that positive isolation-divergence relationships are taxonomically widespread.

Prevalencia de anemia en varias comunidades de la etnia Nivaclé del Chaco paraguayo / Prevalence of anemia in several communities of the Nivaclé ethnic group of the Paraguayan Chaco

La anemia es la concentración de la hemoglobina por debajo de los valores límites establecidos. Las comunidades indígenas de la etnia Nivaclé que habitan el Chaco paraguayo viven bajo condiciones de extrema pobreza, careciendo de asistencia sanitaria y de programas de control de enfermedades. Este estudio descriptivo de corte transversal realizado de junio de 2001 a marzo de 2002, tuvo como objetivo establecer la prevalencia y distribución de anemia en hombres y mujeres de 15 a 65 años, de la etnia Nivaclé que habitan en el Chaco paraguayo. Se incluyó a todos los indígenas voluntarios sanos presentes en el momento del estudio que aceptaron participar, previo consentimiento informado. La concentración de hemoglobina se determinó en 379 indígenas Nivaclé. La OMS considera que existe anemia en los adultos (a partir de 15 años), cuando la concentración de hemoglobina es inferior a 130 g/L para el sexo masculino y menor a 120 g/l para el femenino. La prevalencia de anemia en mujeres n= 217 fue de 49,8 % (con media hemoglobina de 117,67 ± 12,16 g/L); y en los hombres n= 162 resultó de 33,3 % (promedio de hemoglobina de 132,62 ± 11,65 g/L). La elevada prevalencia de anemia observada, especialmente en mujeres, se debería a una pobre nutrición, lo que conlleva a una mala salud que justifica la incorporación de estrategias de atención primaria de salud que se adapten a la cultura y a las condiciones de estas comunidades.

Dysgnathia complex sine holoprosencephaly nor synotia: a case report and discussion of its nosology.

A severe mandibular hypoplasia and microstomy with intraoral anomalies including hypoglossia, fused gums, persistence of buccopharyngeal membrane, and laryngeal hypoplasia were noted in a female newborn with the dysgnathia complex (DC). Additionally, our proposita also presented natal teeth as a probably new finding. These clinical manifestations overlapped with those of the fourth report of hypomandibular faciocranial syndrome (HFS) (31), and given that both lack for craniosynostosis (pathognomonic of HFS), we considered that both represent a subtype of DC proposed as DC sine holoprosencephaly nor synotia (DCSHS). Differential characteristics between the DCSHS, the HFS, and the DC with holoprosencephaly sine synotia are reviewed and additionally, we discussed some aspects about the nosology of the DC.

Maintenance of polymorphic females: do parasites play a role?

The role of parasites in explaining maintenance of polymorphism is an unexplored research avenue. In odonates, female-limited color polymorphism (one female morph mimicking the conspecific male and one or more gynochromatic morphs) is widespread. Here we investigated whether parasitism contributes to color polymorphism maintenance by studying six species of female dimorphic damselflies using large databases of field-collected animals. We predicted that androchrome females (male mimics) would be more intensively parasitized than gynochrome females which is, according to previous studies, counterbalanced by the advantages of the former when evading male harassment compared to gynochrome females. Here we show that in Ischnura denticollis and Enallagma novahispaniae, androchrome females suffer from a higher degree of parasitism than gynochromatic females, and contrary to prediction, than males. Thus, our study has detected a correlation between color polymorphism and parasitic burden in odonates. This leads us to hypothesize that natural selection, via parasite pressure, can explain in part how androchrome and gynochrome female color morphs can be maintained. Both morphs may cope with parasites in a different way: given that androchrome females are more heavily parasitized, they may pay a higher fecundity costs, in comparison to gynochrome females.

Detección por PCR múltiple de gérmenes atípicos en pacientes con neumonía adquirida de la comunidad que concurrieron al INERAM / Multiplex PCR for detection of atypical bacteria in community-acquired pneumonia patients attending INERAM Hospital

La neumonía adquirida en la comunidad (NAC) es una causa relevante de morbilidad y mortalidad. Los métodos convencionales fracasan en la detección de Mycoplasma pneumoniae, Chlamydophila pneumoniae y Legionella pneumophila. Estas bacterias pueden generar procesos infecciosos crónicos y no responden a ciertos antibióticos empleados en el tratamiento empírico de la NAC. Nuestro objetivo fue detectar de forma simultánea, mediante métodos moleculares, M. pneumoniae, C. pneumoniae y L. pneumophila en muestras respiratorias de pacientes con NAC, y describir los gérmenes comunes aislados por métodos microbiológicos convencionales. Estudio observacional descriptivo de corte trasverso realizado en el año 2011, en el que se analizaron 60 muestras respiratorias provenientes de pacientes con NAC atendidos en el INERAM (Instituto de Enfermedades Respiratorias y del Ambiente). Para la PCR múltiple se emplearon primers específicos para genes de los tres microorganismos citados. El protocolo de estudio fue aprobado por los comités científico y ético del IICS y se mantuvieron en estricta confidencialidad los datos personales de los pacientes. La PCR múltiple permitió la amplificación de los genes específicos de estos microorganismos con límites de sensibilidad comprendidos entre 0,05 y 0,001 ng/µL de ADN. M. pneumoniae y C. pneumoniae estuvieron presentes respectivamente en el 18,3% y 1,7% del total de muestras analizadas. No se detectó la presencia de L. pneumophila. Los gérmenes comunes más frecuentemente aislados fueron estreptococos del grupo viridans y Candida spp.La técnica de PCR múltiple permitió detectar M. pneumoniae, C. pneumoniae y L. pneumophila, siendo el primero de los tres el más frecuentemente detectado en pacientes con NAC

Evaluación de parámetros litogénicos en pacientes con urolitiasis que concurrieron al Instituto de Investigaciones en Ciencias de la Salud en el año 2009 / Evaluation of lithogenic parameters in urolithiasis patients attending the Instituto de Investigaciones en Ciencias de la Salud in 2009

Los cálculos renales se forman cuando la concentración de los componentes de la orina alcanzan un nivel en el cual es posible la cristalización. Aunque las manifestaciones clínicas de todos los cálculos son similares, los mismos difieren en su composición, patogénesis y tratamiento. El trasfondo metabólico está asociado a la urolitiasis y la evaluación metabólica es fundamental para establecer un tratamiento específico y evitar las recidivas. En este estudio, observacional descriptivo, de corte trasverso sedeterminaron los valores de analitos con potencial litogénico o inhibidor de cristalización, en muestras de sangre y orina de 40 pacientes de ambos sexos con diagnóstico de urolitiasis que concurrieron al Laboratorio de Análisis Clínicos del IICS de junio a octubredel 2009, así como describir las manifestaciones clínicas más frecuentes. El protocolo del estudio fue aprobado por los comités científico y ético del IICS y durante su ejecución serespetaron principios éticos y científicos. Del total de pacientes, 52,5% fueron niños (n=21, edad media 9±4 años) y 47,5% adultos (n=19, edad media 35±17 años). Sedetectaron alteraciones en los valores de parámetros con potencial litogénico en el 48% de los niños y 87% de los adultos litiásicos. La hipocitraturia y la hipercalciuria fueron los desarreglos metabólicos más frecuentes en ambos grupos. Los síntomas más frecuentesreferidos por los pacientes fueron: cólicos, hematuria y fiebre. La mitad de los pacientes presentaron antecedentes familiares de litiasis renal. El 58% de los pacientes adultos estaba excedido de peso. La ingesta de agua fue inferior a 2 litros en 90% y el 47% de niños y adultos respectivamente. Estos hallazgos señalan la importancia de la evaluación metabólica como herramienta para orientar el diagnóstico y tratamiento adecuado.

Kidney stones are formed when concentration of urinary components reach such a level in which crystallization is possible. Although clinical manifestations of all kidney stones are similar, they differ in composition, pathogenesis and treatment. Metabolic background is associated to urolithiasis and metabolic evaluation is essential to establish specific treatment and avoid recurrences. In this cross-sectional observational descriptive study,we determined the levels of analytes with lithogenic or crystallization inhibitor potential in blood and urine samples of 40 patients, male and female, with diagnosis of urolithiasisthat attended the Department of Clinical Analysis of the IICS from June to October, 2009. Additionally, we describe the most frequent clinical manifestations present in these patients. The study protocol was submitted and approved by the IICS scientific and ethic committees. Of the total number of patients, 52.5% were children (n=21, 9±4 years old) and 47.5% adults (n=19, 35±17 years old). Alterations in the values of the potentially lithogenic parameters were detected in 48% of the children and 87% of the adults. The most frequent metabolic abnormalities were hypocitraturia and hypercalciuria in both groups. The most frequent symptoms were colics, hematuria and fever. Half of the patients referred a family history of urolithiasis. Overweight was detected in 58% of the adult patients. Water intake lower than 2 litres per day was referred by 90% of children and 47% of adults respectively. These findings point out the importance of the metabolic evaluation as a tool to orient adequate diagnosis and treatment.

Developing an effective community conservation program for cotton-top tamarins (Saguinus oedipus) in Colombia.

Developing effective conservation programs that positively impact the survival of a species while considering the needs of local communities is challenging. Here we present an overview of the conservation program developed by Proyecto Tití to integrate local communities in the conservation of Colombia's critically endangered primate, the cotton-top tamarin (Saguinus oedipus). Our comprehensive assessment of the threats effecting the long-term survival of the cotton-top tamarin allowed us to establish the primary components of our program. Proyecto Tití has three areas of emphasis: (1) scientific studies detailing the biology and long-term survival of the cotton-top tamarin, (2) conservation education programs to increase public awareness and conservation knowledge, and (3) community empowerment programs that demonstrate a valuable economic incentive to protecting wildlife and forested areas in Colombia. This integrated approach to conservation that involves local communities in activities that benefit individuals, as well as wildlife, has proven to be remarkably effective in protecting cotton-top tamarins and their forested habitat. Our bindes program, which uses small cook stoves made from clay, has demonstrated a marked reduction in the number of trees that have been harvested for firewood. Developing environmental entrepreneurs, who create products made from recycled plastic for sale in national and international markets, has had a significant impact in reducing the amount of plastic that has been littering the environment and threatening the health of wildlife, while creating a stable economic income for rural communities. Proyecto Tití has provided economic alternatives to local communities that have dramatically reduced the illegal capture of cotton-top tamarins and forest destruction in the region that has positively impacted the long-term survival of this critically endangered primate.

Estudio morfológico de cálculos urinarios de pacientes que concurrieron al Instituto de Investigaciones en Ciencias de la Salud en el 2007 / Morphological analysis of kidney stones from Instituto de Investigaciones en Ciencias de la Salud patients in 2007

Los cálculos renales se forman cuando la concentración de los componentes de orina alcanzan un nivel en el cual es posible la cristalización. Aunque las manifestaciones clínicas de todos los cálculos son similares, los mismos difieren en su composición, patogénesis y tratamiento. La clasificación morfoconstitucional de los cálculos urinarios consiste en la aplicación de criterios, de forma mineralógica y morfológica, que sirven para clasificar los cálculos en tipos morfológicos, cada uno con una composición dominante y a los que pueden atribuirse causas probables de la formación del cálculo. Este trabajo, descriptivo y retrospectivo, hace referencia a los resultados obtenidos del análisis de cálculos provenientes de 50 pacientes, realizados en el año 2007, aplicando los criterios de la clasificación morfoconstitucional. Cada paciente recibió su resultado, asegurando la confidencialidad. Los tipos más frecuentes fueron: IIa en núcleo (44,4%), Ia en capas intermedias y superficiales (37,7% y 44,1%). El tipo IVa1 se encuentra en todos los estratos con porcentajes comprendidos entre 13 al 31,1%. Estos tipos morfológicos están relacionados a condiciones de hipercalciuria, hiperoxaluria e infecciones urinarias respectivamente. La presencia de 2 o más tipos morfológicos asociados se dio en 42 pacientes. La asociación de los tipos Ia+IVa1 se presentó en el 45% de los cálculos bifactoriales. Es la primera vez que se aplica el estudio morfológico en Paraguay, sin necesidad de remitir las muestras al exterior para su análisis. La importancia del análisis de los cálculos es encontrar la causa de la litiasis y orientar hacia el tratamiento más apropiado.

Kidney stones are formed when the concentration of urine components reaches such levels that crystallization is induced. Although clinical symptoms of all types of stones are similar, they differ in the composition, pathogenesis and treatment. Morphoconstitutional classification of kidney stones is made by applying mineralogical and morphological criteria, useful to classify them in different morphological types, each one with a dominant composition and a probable etiological cause of the stone formation. This retrospective study describes the results of the analysis of kidney stones from 50 patients made in 2007, applying criteria of morphoconstitutional classification. Each patient received his results respecting confidentiality. The more frequent types were IIa located in the nucleus (44.4%) and Ia in intermediate and superficial strata (37.7% y 44.1%). Type IVa1 was present in all strata with percentages from 13 to 31.1%. These morphological types are related to hypercalciuria, hyperoxaluria and urinary infections respectively. The presence of 2 o more morphological types was observed in 42 patients. The association of Ia+IVa1 was present in 45% of bifactorial kidney stones. This is the first morphological study of kidney stones in Paraguay, without sending samples abroad. The analysis of kidney stones is important not only to find the cause of the lithiasis but also to select the appropriate treatment.

The repellence of Aristolochia aff. orbicularis roots against the corn borer Sitophilus zeamais.

The repellence of Aristolochia aff. orbicularis root, a native of Xochipala, Guerrero, Mexico, to the corn borer Sitophilus zeamais (Coleoptera) was investigated. The essential oil was isolated from the aromatic root and its repellent effect was assessed. About 40 components of the oil were identified using gas chromatography-mass spectrometry and other spectroscopic methods. The repellence of the roots, the oil and the chromatography fractions were also evaluated. Some fractions had a higher repellence than the total oil.

Microwave processing for scanning electron microscopy.

The normal processing of biological samples for Scanning Electron Microscopy, includes treatment with aldehyde (1 to 2 hours), postfixation with Osmium (1 hour), followed by dehydration in a ascending grade of ethanol (30 a 100%), 10 to 15 minutes in each step, and finally drying. This procedure takes at least 8 hours. In this work, samples of mosquitoes (Aedes), protozoa (Tritrichomonas muris), bacteria (Clostridium oceanicum), murine liver, and small intestine were processed in the same manner in a domestic microwave oven for two minutes at 20% of its maximum power. The complete procedure from the initial fixation to dehydration in 100% ethanol was reduced to one hour with good preservation of the ultrastructural details of the specimens.

I Jornada de prevención, diagnóstico y tratamiento de cáncer de piel en el asentamiento humano Tupac Amaru de Villa / The first working day of prevention, diagnosis and treatment of the skin cancer in the suburban \"Tupac Amaru de Villa\". Lima - Perú

Se aporta los resultados de la I Jornada de Prevención, Diagnóstico y Tratamiento de Cáncer de Piel en una población predominante mestiza, de escasos recursos, y con intensa exposición al sol y al ambiente. Se detecta un sólo caso de cáncer de piel de tipo epitelioma basocelular en un paciente de tipo de piel II, por lo que se plantea la hipótesis de resistencia genética en la población mestiza. La revisión bibliográfica realizada es la primera actividad de prevención y detección de cáncer de piel en el mundo, que incluye el tratamiento quirúrgico y estudio histopatológico.

Heavy metals and organic carbon in sediments from the Tuy River basin, Venezuela.

The Tuy River basin, located in north-central Venezuela with an annual average temperature of 27°C and precipitation of 140 cm, was selected to conduct a geochemical study of bottom sediments, with the object of establishing the natural and human influences in the abundance and distribution of Fe, Mn, Cr, Co, Cu, Ni, Pb, Zn and organic carbon. The basin is lithologically divided into two sub-basins, north and south. The north sub-basin drains a iow-grade metasedimentary terrain with a population density of 800 persons km(-2) and approximateiy 600 industrial sites, while the south sub-basin in underlain by metavolcanic and ultramafic rocks, with a population density of less than 10 persons km(-2).Stream bottom sediment samples (150) were collected during the years of 1979-1986 in 16 unpolluted sites and 13 polluted sites. The sediments were air dried at room temperature and sieved through a 120 stainless steel mesh (125 µm). Samples of grain size smaller than 125 µm were analysed, the heavy metals being determined by atomic absorption spectrometry and the organic carbon (Corg) by dry combustion.The higher concentrations of heavy metals and organic carbon found in the pristine areas were in the south sub-basin, especially in those areas with higher annual precipitation and tropical forest. This indicated that the metavolcanic and ultramafic rocks yield higher concentrations of heavy metals than the metasedimentary rocks. It was also noted that the higher concentrations of Cr and Ni are associated with the ultramafic rocks. The results obtained from the sediment samples collected in the polluted sites showed that the elements Pb, Zn and Corg are enriched up to 4 times as a result of ail the human activities taking place in the basin. Organic carbon is an excellent indicator of domestic wastewater, Pb and Zn are good indicators of the automotive traffic and industrial effluents. The concentrations of each heavy metal did not show any significant correlation with grain size fractions; however, the concentration of organic carbon did show a negative correlation with grain size. The lithological, climatic and vegetation influence in the abundance of heavy metals and organic carbon in stream sediments clearly indicates the necessity of establishing background levels for the area under study when carrying out studies in environmental geochemistry.

Dosificación reducida y simplificada de cimetidina en el tratamiento de la úlcera duodenal. / Reduced dosage of cimetidine in the duodenal ulcer treatment.

Cuarenta pacientes con úlceras duodenales activas demostradas endoscópicamente ingresaron a un estudio por el método del azar y el doble anonimato para comparar la capacidad cicatrizante de una nueva dosificación de cimetidina por la vía oral, consistente en 0.4 g. dos veces al día, frente al esquema de 1.0 g. diario distribuido en cuatro dosis desiguales (0.2 g. después de las tres comidas y 0.4 al acostarse). Los controles clínico y endoscópico fueron realizados por investigadores diferentes; los endoscopistas desconocían todos los detalles clínicos y terapéuticos.Los resultados no mostraron diferencia en las tasas de cicatrización, correspondiendo 94.74% al esquema de cuatro dosis, y 95.24% al de dos. Se observó que el esquema de cuatro dosis producía mejor paliación del dolor propio de la úlcera en las dos primeras semanas, perdiéndose esta diferencia en las dos semanas restantes; la cantidad total de antiácido utilizada ad libitum fue igual en ambos grupos. No se registró efecto colateral atribuible a cimetidina en cualquiera de los esquemas terapéuticos empleados. Es evidente que la dosificación simplificada facilita el cumplimiento del programa medicamentoso.