Variability in electromagnetic field levels over time, and Monte-Carlo simulation of exposure parameters.

This article analyses the electric field levels around medium-wave transmitters, delimiting the temporal variability of the levels received at a pre-established reception point. One extensively used dosimetric criterion is to consider historical levels of the field recorded over a certain period of time so as to provide an overall perspective of radio-frequency electric field exposure in a particular environment. This aspect is the focus of the present study, in which the measurements will be synthesised in the form of exposure coefficients. Two measurement campaigns were conducted: one short term (10 days) and the other long term (1 y). The short-term data were used to study which probability density functions best approximate the measured levels. The long-term data were used to compute the principal statistics that characterise the field values over a year. The data that form the focus of the study are the peak traces, since these are the most representative from the standpoint of exposure. The deviations found were around 6 % for short periods and 12 % for long periods. The information from the two campaigns was used to develop and implement a computer application based on the Monte Carlo method to simulate values of the field, allowing one to carry out robust statistics.

Gastric heterotopic mucosa in the rectum with Helicobacter pylori-like organisms: a rare cause of rectal bleeding.

We report the case of a 9-year-old boy who presented with chronic rectal bleeding. On proctosigmoidoscopy, a polypoid elevation in the rectal ampulla measuring 5 x 3 cm was found. Biopsies were reported to show gastric mucosa. The Giemsa stain showed Helicobacter pylori-like organisms. Including our patient, there are now 30 similar cases reported in the medical literature. The usual manifestations of this rare entity are chronic bleeding and rectal pain. In one-half of cases there is chronic rectal ulceration. The recommended treatment is transanal surgical resection unless there is rectal peptic ulceration. H2 receptor blockers are then advised. Surgical excision is carried out after healing has taken place.

Evaluación de Cisapride en Reflujo Gastroesofágico

En el presente trabajo se estudiaron 16 pacientes con sintomatología clínica de reflujo gastroesofágico, mediante esofagogastroscopia, biopsia de las zonas de esofagitis y gamagrafía para reflujo. Posteriormente se les administró Cisapride 10 mg antes de cada comida y se revaluaron con igual metodología 4 semanas después, anotándose todos los síntomas durante el estudio. Se recurrió a la prueba de Wilcoxon para análisis estadístico. Se analizan los resultados y finalmente se hace una comparación descriptiva con otros fármacos de efecto análogo

Intestinal function and morphology in strongyloidiasis.

Divergent available information on the capability of Strongyloides stercoralis to cause malabsorption prompted a long-term observation in which the nutritional state of the subjects was carefully defined. In spite of moderate to severe symptoms, well nourished patients, even with segmental jejunitis, did not show malabsorption. All patients presenting this parasitic infection with concomitant malnutrition showed absorptive defects. Abnormal absorption persisted in spite of parasitic cure when malnutrition was not immediately corrected, and disappeared with correction of the malnutrition even if parasitic infection was allowed to continue. The present experience indicates that the malabsorption syndrome seen in some cases of S. stercoralis infection is secondary to the concomitant malnutrition and not to the parasite per se.

Gastric cancer in Colombia. III. Natural history of precursor lesions.

The premalignant process in the gastric mucosa was studied by gastroscopic surveys of Colombian populations, and the prevalence of superficial gastritis, chronic atrophic gastritis, and intestinal metaplasia was calculated for population samples having a very high gastric cancer risk (Nariño), very low risk (Cartagena), and intermediate risk (Cali). The prevalence of individuals with normal mucosa in successive age groups was used to estimate "depletion" curves, which were taken as indicators of the dynamics of the premalignant process in each community. Differences corresponding to the geographic variation in stomach cancer risk were found: In the high-risk areas of Nariño, around 75% of the population developed some type of gastritis by 45 years of age, whereas in the low- and intermediate-risk population of Cartagena and Cali, the proportion of such lesions did not exceed 50% at age 45 or thereafter. The effect of environmental factors in early life seemed to be important in determining the prevalence of lesions in each population.