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Biomedical subjects

C Restrepo

Publications and source records attributed to C Restrepo.

48 records · Page 3Linked to original sources

Polyps in a low-risk colonic cancer population in Colombia, South America.

Colonic polyps were systematically searched for in 508 specimens collected from unselected autopsies in individuals more than 10 years of age from Medellín, Colombia, a low-incidence geographic region for colorectal cancer. Adenomatous polyps have a low prevalence rate in both sexes, comparable to that found in Cali, Colombia and other populations with low risk for cancer. They were found more frequently in the right side of the colon and are rare in the sigmoid colon. They begin to appear in the third decade of life in both sexes. Prevalence rates for single and multiple polyps increase with age in both sexes, males showing higher rates than females at every age group. Adenomatous polyps in this population are usually less than 3 mm in diameter and do not show villous changes or epithelial atypia. Hyperplastic polyps were more frequently observed than adenomatous polyps and rates show a progressive increase with age in both sexes. Multiplicity also increases with age. Most polyps are located in the low rectum and sigmoid followed by the cecum and ascending colon. Usually hyperplastic polyps are smaller than 3 mm in diameter and do not show epithelial atypia. Juvenile polyps were infrequently found in this series because children less than 10 years old were excluded. Diverticular disease was also rare and, when found, was not associated with adenomatous polyps. The association between adenomatous polyps and colonic cancer is discussed based on findings in this report.

Adolescent↗

Variations in human aortic fatty streaks among geographic locations.

Histologic features of aortic fatty streaks were examined in male subjects aged 10-39 from Guatemala, Jamaica Negro, Durban Bantu, New Orleans Negro, New Orleans white, Lima and Santiago. These groups were selected from the 19 available in the IAP (International Atherosclerosis Project) because they represented the greatest contrasts between the exten of fatty streaks in the young and raised lesions in the elders. Among these seven groups the extent of raised lesions in the older subjects was significantly but weakly correlated with the type of fatty streaks in the young as measureed by lesion thickness, content of demonstrable lipid, numbers of foam and spindle cells. The severity of leukocytic infilitration and prevalence of foci of necrosis in fatty streaks however, correlated strongly with raised lesions (rank r equals 0.90). We interpret this to imply that the presence of leukocytes and of foci of necrosis in the fatty streak marks its propensity to progress into raised lesions. If this formulation is correct, then the presence of both features in the histology of fatty streaks could be used as a marker in future studies of factors bearing upon the emergence of raised lesions out of fatty streaks.

Adolescent↗

Use of serum lipid and apolipoprotein concentrations to predict extent of diet-induced atherosclerotic lesions in aortas and coronary arteries and to demonstrate regression of lesions in individual rhesus monkeys.

In most studies, the assessment of lesion "regression" is based on comparisons of group means between the "progression" and regression groups. This comparison depends on the assumption that the extent and distribution of lesions produced by the end of the lesion-induction period in the regression animals are equal to those observed in the progression group. To determine whether significant regression of lesions occurs in an individual regression animal, it is necessary to obtain a measure of the lesions produced in these animals at the end of the lesion-induction period. We achieved this goal by developing models using multiple stepwise regression analysis that related steady-state serum cholesterol and apolipoprotein B and A-I concentrations measured during a lesion-induction period in 27 rhesus monkeys fed an atherogenic high-saturated-fat/high-cholesterol diet for 2 years. The models were developed to estimate the percent of intimal surface with lesions, the esterified cholesterol content (micrograms/cm2) for the artery segments, and three histomorphometric measures (mean intimal thickness, mean maximal intimal thickness, and mean percent stenosis) for the coronary arteries. In these models, multiple R2 ranged from 0.42 to 0.74 for the aortas and peripheral arteries, indicating that approximately one half to three fourths of the variance in lesions was accounted for. For the three histomorphometric measures in coronary arteries, however, the multiple R2 was 0.27 or 0.28, indicating that only approximately one fourth of the variance in lesions was accounted for.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Microscopic morphometry of abdominal aorta from men in New Orleans and Guatemala.

Morphometric light microscope measurements were made on 154 abdominal aortas from 77 Guatemalan Indian-white (ladinos) men and from 77 new Orleans white men, aged 15 to 54 years. In each case, means were derived from 12 points measured independently. A progressive increase in intimal lipid with increasing age was observed in men from both countries. Extracellular intimal lipid was consistently higher in men from New Orleans than in those from Guatemala, although not always significantly so. Intimal thickness followed a similar pattern to intimal lipid regarding age and geographic location. Foam cells and leukocytes (mainly monocytes) did not follow a consistent pattern. The smooth muscle cell count was the only variable that was significantly greater in New Orleans men than in Guatemalans aged 15 to 34 years. Morphometric microscopic measurements were significantly correlated with unaided visual estimates of atherosclerotic lesions and with chemical determinations of lipid fractions in the arterial intima. All three methods, gross grading, microscopy, and chemistry, agree in revealing little or nor measureable difference between new Orleans men and Guatemalans younger than 35 years, but an accelerated divergence of the populations over age 35.

Adolescent↗

Regression of experimental atherosclerotic lesions in rhesus monkeys consuming a high saturated fat diet.

Atherosclerotic lesions were induced in rhesus monkeys by feeding them a high-fat, high-cholesterol diet for 2 years. Arteries were examined after autopsy of a subgroup of animals (group P) and cholesterol was removed from the diet of the remaining animals. Lesions were examined in other subgroups after 30 weeks (group R1) and after 52 weeks (group R2). A control group (group C) was fed the diet without cholesterol throughout the study. The mean total serum cholesterol concentration before, during, and after lesion induction was 151, 390, and 157 mg/dl, respectively. The mean percent of surface area with fatty streak or fibrous plaque and the free and esterified cholesterol content of the artery increased in all six arterial segments examined in group P. The means for percent of surface with fatty streak and for arterial cholesterol content or concentration (but not for extent of surface with fibrous plaque) were consistently less in groups R1 and R2 than in group P, although they remained greater in groups R1 and R2 than in group C. The mean intimal thickness for coronary arteries was 10-fold greater in group P than in group C and 60 percent less in groups R1 and R2 than in group P; there was, however, much variability among animals and these differences among groups were not statistically significant. By using several measures in several arterial systems, we have shown that there was regression of diet-induced atherosclerotic lesions in rhesus monkeys while they were fed a diet high in saturated fat but without cholesterol for 30 or 52 weeks.

Animals↗

[Familial incidence of post-streptococcal glomerulonephritis].

The investigation on siblings of AGN patients has shown a streptococcus carrier evidence of 45%, while glomerulonephritis incidence was 15%. These data allowed us to classify our population as highly susceptible to bacterial dissemination and to the development of non-suppurative complications. Renal compromise was clinical and histologically classified. Subclinical forms showed glomerular lesions of mesangial localization, while clinical forms exhibited variable degrees of cellular proliferation. All patients recovered except one who died of a rapidly progressive form.

Adolescent↗