The effect of high altitude on platelet counts, thrombopoietin and erythropoietin levels in young Bolivian airmen visiting the Andes.

Recognition of thrombosis as a complication of exposure to high altitude has stimulated interest in rheological changes resulting from hypobaric hypoxia. Previous studies of platelet counts at high altitude have yielded conflicting results and have not been studied in conjunction with potential mediating cytokines. We studied the effects of high-altitude exposure on platelet numbers, thrombopoietin (tpo) and erythropoietin (epo) levels in man.

Density of intimal smooth muscle cells in the coronary arteries of Bolivians.

Objective: To test an equation that uses measurements of fibroplastic intimal thickening and foam cell infiltrates, precursors for necrotic cores of atherosclerotic plaques in coronary arteries, to compute anticipated amounts of atheronecrosis. Data from New Orleans, La, and La Paz, Bolivia, afforded the opportunity to test the precision of the equation by comparing findings in separate populations.

Methods: Coronary arteries retrieved at autopsy in La Paz, Bolivia, were processed into hematoxylin-eosin-stained paraffin sections along with a parallel series in New Orleans.

Biochemical epidemiology of gallbladder cancer.

To evaluate the a priori hypotheses that an increased level of glyco and tauro lithocholic acid, perhaps because of a decreased capacity for hepatic sulfation, contributed to the biochemical epidemiology of gallbladder cancer, a case-control study was undertaken at four hospitals in La Paz, Bolivia, and at one hospital in Mexico City, Mexico. Eighty-four cases with newly diagnosed histologically confirmed gallbladder cancer were compared with 264 controls with cholelithiasis or choledocholithiasis in the absence of cancer and with 126 controls with normal biliary tracts. All study subjects were undergoing abdominal surgery.

Risk factors for gallbladder cancer. An international collaborative case-control study.

Background: Gallbladder cancer has an unusual geographic and demographic distribution, suggesting many possible etiologies.

Methods: A case-control study was undertaken at four hospitals in La Paz, Bolivia, and at one hospital in Mexico City, Mexico. Eighty-four patients with newly diagnosed, histologically confirmed gallbladder cancer were compared with 126 control subjects without stones and with 264 control subjects with cholelithiasis or choledocholithiasis without cancer.

Rarity of hypertensive stigmata in aging renocortical arteries of Bolivians.

Numerous reports have accumulated from around the world throughout the twentieth century of small, remote, self-sufficient populations that do not show a rise of blood pressure with age. Knowing that renocortical arteriosclerosis, a defining feature of hypertensive nephrosclerosis, is a close commensurate of blood pressure, it can be predicted that the elderly members of such populations should fail to show arteriosclerosis of hypertensive degree in the renal cortex. Emigrants from such populations sometimes come to medical attention in places like La Paz, Bolivia.

Pulmonary endocrine cells of Aymara Indians from the Bolivian Andes.

Introduction: There is evidence to suggest that life at high altitude causes changes in the population of pulmonary endocrine cells, possibly because of exposure to chronic hypoxia. A study was made of the populations of pulmonary endocrine cells in three Aymara Indians and three Mestizos of La Paz (3600 m), Bolivia, which were compared with those in four white lowlanders.

Methods: Pulmonary endocrine cells were immunolabelled for neurone specific enolase and their two major secretory products, gastrin releasing peptide and calcitonin, and their numbers expressed per cm2 of tissue section.

Morphological changes in the pituitary-adrenocortical axis in natives of La Paz.

Increased activity of the hypothalamic-pituitary-adrenocortical axis is part of the response to the stress of initial exposure to hypoxia, but there is evidence to suggest that it persists after homeostatic stability has been regained and acclimatization achieved. The adrenal glands of five lifelong residents of La Paz, Bolivia, who had lived at altitudes in the range 3600-3800 m, were significantly larger than those in age-matched controls from sea level (15.3 g vs 10.

Small pulmonary arterial vessels of Aymara Indians from the Bolivian Andes.

A study was made of the qualitative histological features of the small pulmonary arterial vessels of 25 adult citizens of La Paz, Bolivia (altitude 3600 m) coming to necropsy. Abnormalities found included muscularization of pulmonary arterioles, the development of longitudinal muscle in the intima of pulmonary arteries and arterioles, and the formation of muscular tubes lining the longitudinal muscle which extended through arterioles into the precapillaries of the lung. Arteriolar muscularization was found in three of the 13 Aymaras and in two of the 12 Mestizos studied.

Serum CEA and CA 19-9: potential future diagnostic or screening tests for gallbladder cancer?

The poor prognosis of gallbladder cancer and the presence of high-risk populations make the identification of a screening test for this disease very desirable. As part of an ongoing case-control study of gallbladder cancer being conducted in Mexico City, Mexico, and in La Paz, Bolivia, blood specimens were sought from all patients with cancer of the gallbladder and on controls of similar age and sex undergoing upper abdominal surgery. Each sample was analyzed for carcino-embryonic antigen (CEA) and CA 19-9.

Pulmonary vascular disease in a rabbit at high altitude.

A male weanling rabbit of the New Zealand White strain, born and living at an altitude of 3800 m in La Paz, Bolivia, developed right ventricular hypertrophy. This was found to be associated with growth of vascular smooth muscle cells in the intima of pulmonary arterioles, and contrasted with muscularization of the walls of pulmonary arterioles, without extension into the intima, found in a healthy, high-altitude control rabbit of the same strain. A low-altitude control showed no such muscularization.

Pathophysiology of tumor progression in human gallbladder: flow cytometry, CEA, and CA 19-9 levels in bile and serum in different stages of gallbladder disease.

Gallbladder epithelium is unique among the gastrointestinal cell types because proteins and protein levels in the fluid bathing the luminal side of the cells (bile) are different from and can be compared with those in the fluid bathing the basal side (serum). To help identify cellular changes that occur during the development of gallbladder cancer, we obtained gallbladder tissue, serum, and bile specimens from 20 patients with invasive adenocarcinoma of the gallbladder, three with high-grade dysplasia (carcinoma in situ), six with low-grade dysplasia, 12 with hyperplasia, and 10 with acute or chronic cholecystitis. We obtained serum samples from 40 patients with invasive adenocarcinoma and bile samples from 29 of these patients; serum samples from three with high-grade dysplasia and bile specimens from two of these; serum and bile samples from five with low-grade dysplasia; serum or bile samples from 126 with metaplasia, hyperplasia, or cholecystitis, including serum samples from 121 and bile samples from 110; and serum and bile samples from eight with normal biliary tracts.

Cancer of the gallbladder in Bolivia: suggestions concerning etiology.

In order to investigate the very high incidence of gallbladder cancer in Bolivia, a series of patients with gallbladder cancer and/or cholelithiasis from a hospital in La Paz was compared to a series of patients with cholelithiasis from Philadelphia. Each group demonstrated a similar female predilection. Bolivian patients with gallbladder cancer were older than patients with cholelithiasis who, in turn, were older than the general population (p less than 0.

The epidemiology of cancer of the extra-hepatic biliary tract in Bolivia.

Data on patients with cancer of the gall bladder and cancer of the extra-hepatic bile ducts were obtained from the tumour registry in La Paz, Bolivia. Incidence rates were calculated using the Bolivian census data and compared to US incidence data from the Third National Cancer Survey. The age and population standardized incidence rates for cancer of the gall bladder in Bolivia were 5.

Megacolon at high altitude.

Megacolon occurs frequently in high altitude areas. This report describes observations made in 60 cases seen in La Paz, Bolivia (3,600 meters above sea level). Motility of both the large and small bowel was found to be increased and the feces had a low pH.

Morbidity from cancer in La Paz, Bolivia.

Data from a population-based Cancer Registry in La Paz, Bolivia, are presented. The city is located at approximately 4,000 meters above sea level and has a strong cultural influence consisting of Aymará Indians immigrating from the altiplano. Incidence rates in females are high for cancer of the cervix, the gallbladder and the thyroid gland.

Small pulmonary arteries in some natives of La Paz, Bolivia.

A histological study was made of the small pulmonary blood vessels in pieces of lung obtained at necropsy from 19 long-term residents of La Paz, Bolivia (3800 m). There was variation in the response of the pulmonary vasculature of these subjects to the chronic hypoxia of high altitude. The most characteristic finding, seen in seven of the 16 cases beyond infancy, was distal extension of vascular smooth muscle into pulmonary arterioles as small as 20 micrometer in diameter.

Diseases of the colon and rectum in Bolivia.

A review of the surgical and autopsy records from two general hospitals in La Paz, Bolivia, discloses an incidence of colon and rectal disease, excluding hemorrhoids, of 0.6 per cent (138 of 22,361 surgical cases) and 2.5 per cent (16 of 640 consecutive autopsies).