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Biomedical subjects

E Caceres

Publications and source records attributed to E Caceres.

At least 37 records · Page 2Linked to original sources
PubMed1995

Training in hypoxia vs. training in normoxia in high-altitude natives.

To determine the interactions between endurance training and hypoxia on maximal exercise performance, we performed a study on sedentary high-altitude natives who were trained in normoxia at the same relative (n = 10) or at the same absolute (n = 10) intensity of work as hypoxia-trained subjects (n = 10). The training-induced improvement of maximal oxygen uptake (VO2max) in hypoxia-trained subjects was similar to that obtained in normoxia-trained sea-level natives submitted to the same training protocol (H. Hoppeler, H. Howald, K. Conley, S. L. Lindstedt, H. Claassen, P. Vock, and E. W. Weibel. J. Appl. Physiol. 59: 320-327, 1985). Training at the same absolute work intensity in the presence of increased oxygen delivery failed to provide a further increase in VO2max. VO2max was not improved to a greater extent by simultaneously increasing absolute work intensity and O2 delivery during the training sessions. In addition, training in normoxia is accompanied by an increased blood lactate accumulation during maximal exercise, leading to greater drops in arterial pH, bicarbonate concentration, and base excess. We conclude that, in high-altitude natives, 1) training at altitude does not provide any advantage over training at sea level for maximal aerobic capacity, whether assessed in chronic hypoxia or in acute normoxia; 2) VO2max improvement with training cannot be further enhanced by increasing O2 availability alone or in combination with an increased work intensity during the exercising sessions; and 3) training in normoxia in these subjects results in a reduced buffer capacity.

Adult↗
PubMed1994

Total lung capacity in young highlanders of Aymara ancestry.

Total lung capacity (TLC) and its components, including residual volume (RV) and vital capacity (VC), are described in a sample of 164 male and 143 female youths of Aymara ancestry (10.0-19.9 years) who were born and raised at high altitudes (> 2,500 m) and who were residing in La Paz, Bolivia (average altitude of about 3,600 m). The hypothesis was tested that the enhanced lung volumes of adult highlanders are attained during the period of growth and development. As found in adult male highlanders, TLC in young highlanders was significantly larger than in lowlanders of the same sex and body size, primarily as a result of increases in RV and secondarily through increases in VC. In addition, estimates of the magnitude of the effect of chronic hypobaric hypoxia on all of the measures of pulmonary function, including TLC, RV, and VC, were positively related to age. This finding suggests that growth and development at high altitude is associated with a constant increase in TLC and other measures of pulmonary function relative to those of lowlanders, a finding which is consistent with the expectations of the developmental adaptation hypothesis. However, although these relationships were statistically significant in males, they were not significant in females. Thus, although the magnitude of the estimated effects of chronic hypobaric hypoxia on TLC, RV, and VC were similar in males and females, the developmental pattern by which these enhanced volumes are achieved may differ between sexes.

Adolescent↗
PubMed1994

Effect of chronic hypoxia and socioeconomic status on the maximal oxygen uptake of 10- to 12-year-old Bolivian boys.

The aim of this study was to analyze the effect of altitude and socioeconomic status on the maximal oxygen uptake (VO2max) of prepubertal Bolivian boys. The subjects were 143 prepubertal boys (10 to 11.5 years old) living in La Paz (altitude 3600 m, n = 67) and Santa Cruz de la Sierra (altitude 420m, n = 76). At high altitude, 23 boys were from a high socioeconomic status (HAHSES) and 44 from a low socioeconomic background (HALSES). At low altitude, 29 boys were from a high socioeconomic level (LAHSES) and 47 from a low socioeconomic background (LALSES). Anthropometric characteristics were determined in order to assess the physical growth of the boys. The VO2max was determined from a progressive maximal exercise (direct method). The subjects performed this test using the same cycle ergometer at both high and low altitudes. For the overall anthropometric parameters, there was no significant difference between highland and lowland boys of the same socioeconomic status. However, regardless of altitude, boys from a low socioeconomic background were 2 years behind those from a high socioeconomic background. There was no significant difference for VO2max between boys from high and low socioeconomic backgrounds at HA (HAHSES: 37.2 +/- 5.6; HALSES: 38.9 +/- 6.4 ml.min-1.kg-1 body weight) and at LA (LAHSES: 42.6 +/- 5.4; LALSES: 43.1 +/- 4.9 ml.min-1.kg-1 body weight). The VO2max of highland boys was, on average, 11% lower than that of lowland boys. It appears, therefore, that a difference in socioeconomic status has no effect on the VO2max (ml.min-1.kg-1) of prepubertal children at low altitude as well as the altitude of 3600m.

Altitude↗
PubMed1990

Treatment of breast cancer by radical surgery: a personal experience of 653 patients with minimal follow-up of 10 years.

From June 1952 through December 1976, 695 radical operations were performed on 653 women suffering from invasive cancer of the breast. All operations were performed by a single surgeon (E.C.); the same principles in the selection of the patient techniques of surgery and overall treatment were practiced. Postoperative radiation therapy was used only in the beginning of the study, and 56 (15.9%) of the group with axillary metastases received such therapy. No patient with negative axillary lymph node received radiation therapy. No postoperative adjuvant chemotherapy or immunotherapy was administered. Complete follow-up data were obtained in 94.7% of all patients. In accord with the UICC clinical classification, 96 were classified as stage I (14.7%), 445 as stage II (68.1%), and 111 as stage III (17.%); 1 (0.1%) was not classified. From the 653 patients, 651 (two postoperative deaths) were observed for an average of 141.9 months. The longest period of follow-up evaluation for any patient was more than 35 years and the minimum, 10 years. Survival was calculated for the entire study group and for patients classified by nodal status and stage of disease. The 10-year overall survival rate for 651 patients is 60.4%; for those with positive nodes 46.4%, and for those with negative nodes, 76.7%. The overall survival, according to clinical stage, was as follows: the 5-year survival for patients in stage I was 89.5%, and the 10-year survival was 83.1%. In the stage II group, the 5-year survival was 76.1% and the 10-year survival, 58.5%. The patients in stage III had only a 62.1% 5-year survival and a 47.7% 10-year survival.

Adult↗
PubMed1990

Incidence of regional lymph node metastasis in operable osteogenic sarcoma.

Records of 182 consecutive patients with the diagnosis of operable osteogenic sarcoma, treated between 1954 through 1980 by the Breast, Bone and Mixed Tumors Department of the Instituto Nacional de Enfermedades Neoplasicas (Lima, Peru), were reviewed to study the incidence of regional lymph node metastases in this disease. All the patients included in this study had radical surgery, which means the complete resection of the bone where the tumor is located, including the proximal joint, which permitted excision of the regional lymph nodes. Nineteen patients (10.4%) had evidence of sarcoma metastatic to draining lymph nodes. A comprehensive analysis of the literature shows that the incidence of metastasis to the lymph nodes in this study, is higher than those cited in a review of the literature, probably due to the policy in the management of osteogenic sarcoma in our institution, during the period of study.

Adolescent↗
PubMed1990

Distribution and etiology of leishmaniasis in Colombia.

A total of 340 Leishmania strains, isolated from humans, animals, and sand flies from various regions of Colombia, were examined by isozyme electrophoresis. Seven different Leishmania species were identified. Leishmania panamensis and L. braziliensis were the most common, representing 53.8% and 30.3% of the total, respectively. Isolation rates of the other species were as follows: L. chagasi, 9.4%; L. guyanensis, 2.6%; L. amazonensis, 1.8%; L. mexicana, 0.8%; and a new species requiring additional study, 1.2%. Statistical analyses of representative L. panamensis and L. braziliensis isolates indicated that the populations of these 2 species are genetically very similar. L. panamensis may have a continuous distribution in Colombia west of the eastern Andes Mountains and L. braziliensis may have a continuous distribution east of the western Andes Mountains. Information is given on disease manifestations of the parasites in human hosts and on isolation records from sand flies and animals.

Animals↗
PubMed1990

[Financing research in Chile in biotechnology and other areas related to the productive sector].

This study describes the financial support for research in Chile in different areas related to the productive sector including biotechnology. Four different sources which help research in the country through competitive research grants were analysed. These include: FONDECYT (National Fund for Research and Technology), Fondo de Desarrollo Productivo de CORFO (Fund for Productive Development), Fondo de Investigaciones Agropecuarias (Fund for Research in Agriculture and Livestock) and the IV Program for Technical Cooperation between the Chilean Government and UNDP. Biotechnology appears as one of the areas related to the productive sector having an important number of projects approved with a substantial financial support. Based in a survey, recommendations are made to improve the relationship between the productive and academic sector in biotechnology and other areas.

Biotechnology↗
PubMed1989

A prospective double-blind trial of a low molecular weight heparin once daily compared with conventional low-dose heparin three times daily to prevent pulmonary embolism and venous thrombosis in patients with hip fracture.

In a randomized, prospective, double-blind trial, the effect of conventional low-dose heparin (5,000 units every 8 hours) was compared with that of a low molecular weight fragment (2165 LMWH, Kabi Vitrum AB, starting 2,500 units 2 hr before surgery, and then 5,000 units subcutaneously every morning for 9 days). A total of 90 patients admitted because of hip fracture fulfilled the inclusion criteria and were analyzed for development of pulmonary embolism and deep vein thrombosis: 46 patients were included in the low molecular weight heparin (LMWH) group, and 44 in the conventional heparin group. Two and three, respectively, died before diagnostic tests were performed. In the remaining patients a ventilation-perfusion lung scan was performed 8 days after intervention. In the first 57 patients studied a bilateral ascending venography was performed on the ninth day only if clinical symptoms suggested a deep venous thrombosis. Because of the rate of venous thrombosis detected in those patients was unexpectedly low, venography was requested in the remaining 33 patients, even if the screening tests were negative. Pulmonary embolism occurred in six patients, all in the LMWH group. Deep vein thrombosis occurred in 14 patients in the LMWH group and in six patients in the conventional heparin group. Both differences are statistically significant. Mortality did not differ between the groups, nor did haemorrhagic complications. Our findings suggest that, in patients with hip fracture, LMWH is not useful at the dosage used.

Aged↗
PubMed1989

Epidemiology of visceral leishmaniasis in Colombia.

Epidemiologic studies were conducted during the period 1986-1988 in a small rural community in Colombia (El Callejon) where visceral leishmaniasis is highly endemic. In this community of 185 people, 14 cases of infantile visceral leishmaniasis were diagnosed in the 9 years 1981-1988. Leishmanin skin testing of a sample of the human residents showed that prevalence of Leishmania chagasi infection increased with age; overall, 51.2% of the subjects had a positive reaction. A canine surveillance program was instituted, using introduced sentinel dogs as well as the indigenous dog population. Eleven of 16 sentinel dogs were infected within 8 months of exposure; mean seroconversion time was 4.4 months. Eleven of 25 seronegative local dogs were also infected during the 26 month period; mean seroconversion time was 8 months. Parasites identified by isozyme electrophoresis as L. chagasi were recovered from 18 of 22 seropositive dogs. Collections of wild animals using baited live traps yielded mainly the neotropical opossum, Didelphis marsupialis. Leishmania chagasi was recovered from 12 of 37 (32.4%) opossums. Six of 681 female Lutzomyia longipalpis collected in the community had flagellates in their guts; cultures from 4 were identified as L. chagasi. These data confirmed that active parasite transmission occurred. The relatively high prevalence of L. chagasi infection found among D. marsupialis captured near human dwellings suggests that these animals may be an important peridomestic reservoir.

Age Factors↗
PubMed1988

Effect of altitude on the lung function of high altitude residents of European ancestry.

The forced vital capacity (FVC), forced expiratory volume in one second (FEV), and ratio of FEV to FVC (%FEV) of 161 male and 158 female youths of European ancestry who were born at high altitudes and who were residing in La Paz, Bolivia (average altitude of 3,600 m) were examined and compared with those for lowland Europeans and highland Aymara Amerindians. FVC and FEV were significantly larger (p less than .001) in the La Paz Europeans than in two lowland control samples of European ancestry, with the relative differences between samples varying from small (1.5-4.1%) to moderate (7.7-11.9%). It could not be determined whether the enhanced lung volumes of the La Paz European children were acquired through an accelerated development of lung volumes relative to stature during adolescence, as is the case for Amerindian highlanders. After controlling for body and chest size, FVC and FEV were significantly smaller in the La Paz Europeans than in highland Aymara (p less than .001), suggesting that the lung volumes of the Aymara are influenced by factors other than simply growth and development at high altitude. Finally, as found in Amerindians, chest size is an important determinant of intra-individual variation in lung function among highland Europeans.

Adolescent↗
PubMed1988

Two years of cyclophosphamide and 5-fluorouracil as adjuvant chemotherapy for stage II and III breast carcinoma.

The results after 6 years of a prospective clinical trial of adjuvant chemotherapy with a regimen of two drugs--cyclophosphamide and 5-fluorouracil (CF)-- for 2 years in 97 women with stage II or III breast cancer are reported. Eligible patients were free from distant metastases. All patients began adjuvant therapy within 4 weeks of surgery; therapy consisted of radical, modified, or extended radical mastectomy. No postoperative radiotherapy was given. The results are compared with a historical control group from previous consecutive patients treated by surgery alone. Patients were stratified by age (younger than 50 or older than or equal to 50) and nodal status (one to three positive axillary nodes vs. four or more positive nodes). The estimated 6-year survival was 60% for CF patients vs. 31% for control patients (P = 0.001). The estimated 6-year disease-free survival was 53.6 and 30.3% for CF and control, respectively (P = 0.007). There was a trend toward longer disease-free survival (DFS) and survival (S) in patients treated with CF, but this was not significant in all the subgroups. Disease-free survival was statistically significant in the subgroup of women greater than or equal to 50 years old with one to three positive nodes (P = 0.038); survival in the patients less than or equal to 49 years old with four or more positive nodes (P = 0.0036); and in patients greater than or equal to 50 years old with one to three lymph nodes involvement (P = 0.038).

Adult↗
PubMed1987

Radiotherapy in the management of locally advanced breast cancer.

A retrospective study of 484 patients with locally advanced cancer of the breast treated with irradiation alone revealed a partial or complete response in 64% of the patients, with a mean duration of 13 months. The 5-year survival was 21.9% for the entire group of patients; 32% for patients responding, and 5% for non-responding patients. The data suggests that the size of the tumor and the age of the patients influence the quality of response. The results indicate that radiotherapy adequately controls local disease in a significant number of patients but systemic treatment is needed for better disease control.

Adult↗
PubMed1986

Postoperative whole lung irradiation with or without adriamycin in osteogenic sarcoma.

Thirty-six patients with histologically proven osteogenic sarcoma of the extremities, treated between September 1975 and April 1978, are the subject of this report. The primary tumor was treated with radical surgery. Patients received 2000 cGy whole lung irradiation postoperatively in an attempt to control micrometastases to the lung. Twenty-nine of the patients were given Adriamycin (60 mg/m2 IV every 6 weeks for a total dose of 550 mg/m2) in addition to the irradiation. The median, disease-free interval was 118 days for the seven patients treated with lung irradiation only. The median overall survival for these patients is 241 days, with one patient alive with disease. All patients developed lung metastasis. For the 29 patients treated with postoperative lung irradiation and Adriamycin, the median disease-free interval was 372 days, and the median overall survival is 843 days. Nineteen of the patients recurred (65.5%). The differences are statistically significant (p less than or equal to 0.003, median disease-free survival and p less than or equal to 0.03, median survival). This study supports the role of whole lung irradiation plus Adriamycin, in the control of micrometastases in osteogenic sarcoma of the extremities and suggests that additional clinical trials are warranted.

Adolescent↗
PubMed1984

The physical growth of urban children at high altitude.

The physical growth of urban Aymara children residing in La Paz, Bolivia (3,600 m) is described and compared with Amerindian children residing at low and high altitudes and with low-altitude U.S. children. The sample consists of 227 males (10.6-19.7 yr) and 219 females (11.2-19.8 yr). The urban La Paz children were taller at all ages than rural high altitude Amerindian children but similar in stature to urban high altitude children from Peru. The variation in stature among the high altitude populations was considerable, amounting to average differences between the tallest and shortest samples of about 10 cm in males and 8 cm in females. In addition, stature in the two urban high altitude samples was similar to that of rural low-altitude Amerindians. This overlapping of the distributions of stature in high- and low-altitude populations could easily confound comparisons designed to determine the effects of hypoxia on physical growth. La Paz Aymara children had considerably smaller chest sizes relative to stature than high-altitude Quechua children. However, the available data indicates that relative chest sizes are similar in Aymara and Quechua adults, suggesting that the process by which large chests are achieved may differ between these Andean populations.

Adolescent↗
PubMed1984

Local control of osteogenic sarcoma by radiation and chemotherapy.

Sixteen patients with osteogenic sarcoma of limbs were treated with high dose methotrexate followed by leucovorin rescue, adriamycin and radiotherapy to the primary tumor. A post-treatment surgical biopsy was performed in 15 of the 16 patients. In 12 of 15 patients (80%), the follow-up biopsy was negative for active tumor. Complications of treatment were myelosuppression (16 cases), moist desquamation (13 cases), soft tissue necrosis (2 cases) local infection (2 cases), fibrosis (9 cases) and bone fracture (4 cases). The mean survival time in this group of patients was 712 days.

Adolescent↗
PubMed1983

Radical mastectomy versus radical mastectomy plus internal mammary dissection. Ten year results of an international cooperative trial in breast cancer.

A multicentric randomized trial evaluated the interest of internal mammary dissection on operable breast cancer patients. One thousand four hundred and fifty-three patients were included in the study and were followed for ten years. There is no difference in survival or in relapse-free survival between the two groups. There were significantly more local recurrences in the group without internal mammary dissection, but these recurrences occurred mainly on patients who developed metastases. A great difference between centers was observed in the number of nodes examined and there is therefore a difference in the prognostic value of the number of nodes invaded.

Breast Neoplasms↗