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E Vargas

Publications and source records attributed to E Vargas.

At least 37 records · Page 2Linked to original sources
PubMed1998

Hemoglobin concentration of high-altitude Tibetans and Bolivian Aymara.

Elevated hemoglobin concentrations have been reported for high-altitude sojourners and Andean high-altitude natives since early in the 20th century. Thus, reports that have appeared since the 1970s describing relatively low hemoglobin concentration among Tibetan high-altitude natives were unexpected. These suggested a hypothesis of population differences in hematological response to high-altitude hypoxia. A case of quantitatively different responses to one environmental stress would offer an opportunity to study the broad evolutionary question of the origin of adaptations. However, many factors may confound population comparisons. The present study was designed to test the null hypothesis of no difference in mean hemoglobin concentration of Tibetan and Aymara native residents at 3,800-4,065 meters by using healthy samples that were screened for iron deficiency, abnormal hemoglobins, and thalassemias, recruited and assessed using the same techniques. The hypothesis was rejected, because Tibetan males had a significantly lower mean hemoglobin concentration of 15.6 gm/dl compared with 19.2 gm/dl for Aymara males, and Tibetan females had a mean hemoglobin concentration of 14.2 gm/dl compared with 17.8 gm/dl for Aymara females. The Tibetan hemoglobin distribution closely resembled that from a comparable, sea-level sample from the United States, whereas the Aymara distribution was shifted toward 3-4 gm/dl higher values. Genetic factors accounted for a very high proportion of the phenotypic variance in hemoglobin concentration in both samples (0.86 in the Tibetan sample and 0.87 in the Aymara sample). The presence of significant genetic variance means that there is the potential for natural selection and genetic adaptation of hemoglobin concentration in Tibetan and Aymara high-altitude populations.

Adaptation, Physiological↗
PubMed1998

Dermal infiltrate of enlarged macrophages in patients receiving chemotherapy.

A histologically distinct maculopapular eruption has been associated with the use of recombinant forms of granulocyte and granulocyte-macrophage colony-stimulating factors (GCSF and GMCSF). One of the most distinctive features was an increase in the number and the size of dermal macrophages, which was proposed as a clue to diagnosis of these cytokine-induced dermatoses. We describe 8 patients who received chemotherapy and who developed a maculopapular eruption, of which histological examination showed an increase in the number and the size of dermal macrophages. Three patients had also received GM-CSF or G-CSF, before the onset of rash, but 5 patients had not. In conclusion, an increase in the number and the size of dermal macrophages is not specific for the reaction to GM-CSF or G-CSF, and may also be observed in patients receiving chemotherapy.

Adult↗
PubMed1998

Comparison of the safety and efficacy of the fixed combination of dorzolamide/timolol and the concomitant administration of dorzolamide and timolol: a clinical equivalence study. International Clinical Equivalence Study Group.

AIMS: To compare the tolerability and efficacy of a fixed combination solution of dorzolamide/timolol (Cosopt), administered twice daily with the concomitant administration of its components, dorzolamide (Trusopt) twice daily and timolol (Timoptic) twice daily. METHODS: After a 2 week timolol run in, patients with open angle glaucoma or ocular hypertension were randomised (1:1) to receive treatment with either the dorzolamide/timolol combination solution twice daily (combination) or the dorzolamide solution twice daily plus timolol maleate solution twice daily (concomitant) for 3 months. RESULTS: 299 patients were entered and 290 patients completed the study. Compared with the timolol baseline, additional IOP lowering of 16% was observed at trough (hour 0) and 22% at peak (hour 2) at month 3 in both the concomitant and combination groups. The IOP lowering effects of the two treatment groups were clinically and statistically equivalent as demonstrated by the extremely small point differences (concomitant--combination) observed in this study--0.01 mm Hg at trough and 0.08 mm Hg at peak. The safety variables of the concomitant and combination groups were very similar. Both combination and concomitant therapy were well tolerated and few patients discontinued due to adverse effects. CONCLUSIONS: The dorzolamide/timolol combination solution administered twice daily is equivalent in efficacy and has a similar safety profile to the concomitant administration of the components administered twice daily.

Adult↗
PubMed1997

Ventilation and hypoxic ventilatory response of Tibetan and Aymara high altitude natives.

Newcomers acclimatizing to high altitude and adult male Tibetan high altitude natives have increased ventilation relative to sea level natives at sea level. However, Andean and Rocky Mountain high altitude natives have an intermediate level of ventilation lower than that of newcomers and Tibetan high altitude natives although generally higher than that of sea level natives at sea level. Because the reason for the relative hypoventilation of some high altitude native populations was unknown, a study was designed to describe ventilation from adolescence through old age in samples of Tibetan and Andean high altitude natives and to estimate the relative genetic and environmental influences. This paper compares resting ventilation and hypoxic ventilatory response (HVR) of 320 Tibetans 9-82 years of age and 542 Bolivian Aymara 13-94 years of age, native residents at 3,800-4,065 m. Tibetan resting ventilation was roughly 1.5 times higher and Tibetan HVR was roughly double that of Aymara. Greater duration of hypoxia (older age) was not an important source of variation in resting ventilation or HVR in either sample. That is, contrary to previous studies, neither sample acquired hypoventilation in the age ranges under study. Within populations, greater severity of hypoxia (lower percent of oxygen saturation of arterial hemoglobin) was associated with slightly higher resting ventilation among Tibetans and lower resting ventilation and HVR among Aymara women, although the associations accounted for just 2-7% of the variation. Between populations, the Tibetan sample was more hypoxic and had higher resting ventilation and HVR. Other systematic environmental contrasts did not appear to elevate Tibetan or depress Aymara ventilation. There was more intrapopulation genetic variation in these traits in the Tibetan than the Aymara sample. Thirty-five percent of the Tibetan, but none of the Aymara, resting ventilation variance was due to genetic differences among individuals. Thirty-one percent of the Tibetan HVR, but just 21% of the Aymara, HVR variance was due to genetic differences among individuals. Thus there is greater potential for evolutionary change in these traits in the Tibetans. Presently, there are two different ventilation phenotypes among high altitude natives as compared with sea level populations at sea level: lifelong sustained high resting ventilation and a moderate HVR among Tibetans in contrast with a slightly elevated resting ventilation and a low HVR among Aymara.

Acclimatization↗
PubMed1997

Patterns of uveitis as a guide in making rheumatologic and immunologic diagnoses.

OBJECTIVE: To describe the patterns of clinical presentation in a series of 407 patients with uveitis and to establish the relationship between these patterns and the final diagnosis. METHODS: Patients were referred to the Uveitis Clinic of a tertiary hospital from January 1992 to January 1996. All patients received a complete ophthalmologic examination, and a general clinical history was obtained. The current International Uveitis Study Group classification system was used for anatomic classification. To establish the final diagnosis of the most common entities causing uveitis, current diagnostic criteria were used. A discriminant analysis, with diagnostic grouping as the outcome variable and the clinical presentation features as discriminating variables, was performed. RESULTS: With our classification system, 66.5% of the cases could be correctly classified according to the clinical pattern and morphologic findings. By diagnostic groups, discriminant analysis showed that 75% of patients with Behçet's disease, 77.1% of those with spondylarthropathy (including inflammatory bowel disease), 33.3% of those with sarcoidosis, 97.9% of those with toxoplasmosis, 85.7% of those with Vogt-Koyanagi-Harada syndrome, 100% of those with herpes, and 50.4% of those with idiopathic uveitis were correctly classified. In the miscellaneous group, which included disease entities with fewer than 5 cases, 42.9% were correctly classified. CONCLUSION: Rheumatologic evaluation of the patient with uveitis can be more cost-effective if the referring ophthalmologist follows the classification system described herein, allowing a tailored approach in which only specific and necessary diagnostic tests are used.

Adolescent↗
PubMed1997

Use of albumin in two Spanish university hospitals.

OBJECTIVES: The aim of this study was to characterize the use of seralbumin, evaluating how appropriate its prescription is and what possible economic repercussions may result from inappropriate use. METHODS: We performed a prospective study that included all patients receiving albumin in two University Hospitals from October 1995 to March 1996. The reasons for albumin use were considered appropriate if they coincided with the recommendations of a panel of experts. RESULTS: During the study period, 197 patients received albumin and a total of 3208 50-ml vials (20%) were used. The internal medicine and gastroenterology services prescribed this drug the most often. The most frequent prescription motives were paracentesis in cirrhotic patients (25.9%), hypoalbuminemia (24.9%) and chronic handling of cirrhotic patients (18.6%). Only 16 prescriptions (8.1%) (corresponding to 315 vials, 9.8%) were considered appropriate. One cause of inappropriate prescribing was that colloid solutions had not previously been used in 56 (30.9%) of the 186 inappropriate prescriptions. During the study period, 74,306 ECUs were spent on inappropriate indications. CONCLUSIONS: The use of albumin in our centers is incorrect and has important economic repercussions. Some educational and informative measures must be established to change this situation.

Albumins↗
PubMed1995

Developmental, genetic, and environmental components of aerobic capacity at high altitude.

The aerobic capacity of 268 subjects (158 males and 110 females) was evaluated in La Paz, Bolivia situated at 3,750 m. The sample included 1) 39 high altitude rural natives (all male); 2) 67 high altitude urban natives (32 male, 35 female); 3) 69 Bolivians of foreign ancestry acclimatized to high altitude since birth (37 male, 32 female); 4) 50 Bolivians of foreign ancestry acclimatized to high altitude during growth (25 male, 25 female); and 5) 42 non-Bolivians of either European or North American ancestry acclimatized to high altitude during adulthood (25 male, 18 female). Data analyses indicate that 1) high altitude urban natives, acclimatized to high altitude since birth or during growth, attained higher aerobic capacity than subjects acclimatized to high altitude during adulthood; 2) age at arrival to high altitude is inversely related to maximum oxygen consumption (VO2 max) expressed in terms L/min or ml/min/kg of lean body mass, but not in terms of ml/min/kg of body weight; 3) among subjects acclimatized to high altitude during growth, approximately 25% of the variability in aerobic capacity can be explained by developmental factors; 4) as inferred from evaluations of skin color reflectance and sibling similarities, approximately 20 to 25% of the variability in aerobic capacity at high altitude can be explained by genetic factors; 5) except among the non-Bolivians acclimatized to high altitude during adulthood, the aerobic capacity of individuals with high occupational activity level is equal to the aerobic capacity of high altitude rural natives; and 6) the relationship between occupational activity level and aerobic capacity is much greater among subjects acclimatized to high altitude before the age of 10 years than afterwards. Together these data suggest that the attainment of normal aerobic capacity at high altitude is related to both developmental acclimatization and genetic factors but its expression is highly mediated by environmental factors, such as occupational activity level and body composition.

Acclimatization↗
PubMed1995

Chromosome-encoded inducible copper resistance in Pseudomonas strains.

Nine Pseudomonas strains were selected by their high copper tolerance from a population of bacteria isolated from heavy-metal polluted zones. Copper resistance (Cu(r)) was inducible by previous exposure of cultures to subinhibitory amounts of copper sulfate. All nine strains possessed large plasmids, but transformation and curing results suggest that Cu(r) is conferred by chromosomal genes. Plasmid-less Pseudomonas aeruginosa PAO-derived strains showed the same level of Cu(r) as environmental isolates and their resistance to copper was also inducible. Total DNA from the environmental Pseudomonas, as well as from P. aeruginosa PAO strains, showed homology to a Cu(r) P. syringae cop probe at low-stringency conditions but failed to hybridize at high-stringency conditions.

Chromosomes, Bacterial↗
PubMed1994

Anthropometry and lung function of 10- to 12-year-old Bolivian boys.

Anthropometric measurements of 23 HAHSES, 44 HALSES, 43 LAHSES, and 28 LALSES boys (see Introduction to this Supplement) are presented here. They include body height (H), body weight (BW), upper arm circumference (UAC), and skinfold thickness taken at four locations. From these measurements, body fat, lean body mass, and body mass index (BMI = BW/H2) were calculated. The degree of maturation was assessed according to Tanner, orchidometry, and by quantification of testosterone in saliva. Lung function data include: vital capacity (VC), forced expired volume per 1 s (FEV1), functional residual capacity (FRC), residual volume (RV), and total lung capacity (TLC). The results show enhanced lung volumes in both HA groups in comparison to LA groups, with HALSES boys having the greatest increase, even though the LSES boys were significantly smaller compared to the HSES boys at both altitudes and their growth was delayed by approximately 2 years. From the anthropometric data it appears that physical growth of prepubertal boys is dependent on SES but not on high-altitude exposure. We tentatively conclude that chronic hypoxia per se does not affect physical growth in prepubertal boys in an Andean environment and that development of lung function is accelerated in relation to linear growth as has been suggested by other authors (15).

Altitude↗
PubMed1993

Is there a relationship between supine systemic blood pressure and orthostatic hypotension in the elderly?

The relationship between blood pressure and orthostatic hypotension was studied in 48 elderly patients with orthostatic hypotension and 29 healthy age-matched controls. Individuals were designated as hypertensive (systolic > 160 and or diastolic > 90 mmHg) or normotensive on the basis of supine blood pressure levels. Systolic, diastolic and mean blood pressures, heart rate, stroke volume, cardiac output, cardiac index and total peripheral resistance were measured every 5 min before, during and after 10 min head-up tilt to 70 degrees. Eighteen orthostatic hypotension subjects and six controls were hypertensive, while 30 orthostatic hypotension subjects and 23 controls were normotensive. There were no differences between hypertensive and normotensive patients in mean age, weight, height or body surface area. Mean systolic blood pressure in orthostatic hypotension subjects was higher than in controls (148.8 +/- 3.6 vs. 137.5 +/- 3.34 mmHg). Mean diastolic pressure was not different (79.1 +/- 2.0 vs. 79.0 +/- 2.0 mmHg). There were no differences between patients with or without hypertension in the haemodynamic changes produced by head-up tilt. Heart rates in orthostatic hypotension subjects with hypertension were significantly lower throughout the study when compared with normotensive orthostatic hypotension patients. Further, the increases in heart rate on tilting were significantly smaller (8.4 +/- 1.9 vs. 14.5 +/- 1.8 beats/min). Control hypertensive subjects had significantly higher mean cardiac output and cardiac index compared with non-hypertensives from before and during tilt. We conclude that hypertension is not related to the development or the degree of orthostatic hypotension in the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Sleep apneas in high altitude residents (3,800 m).

The question is: to what extent periodic breathing usually observed in translocated subjects at high altitude affects normal and polycythemic residents of high altitude? Standard sleep parameters, chest wall movements, temperature of ventilated gas and arterial O2 saturation (SaO2) were continuously recorded in 7 normal highlanders (mean hematocrit: 51%) and 14 polycythemic highlanders (mean hematocrit: 68%) during one night in La Paz, 3,850 m, Bolivia. The patterns of breathing instability were analysed by two ways: measuring duration of apneas and counting all the oscillations of SaO2 greater than 1%. Normal and polycythemic highlanders displayed a wide intersubject variability with regard to breathing instability, hence no significant difference in the total number of apneas and oscillations of SaO2 could be evidenced between the 2 groups. However, the longest apneas and the highest number of oscillations of SaO2 were found in the polycythemic highlanders.

Adaptation, Physiological↗
PubMed1992

Reduced corrosion of CP Ti and Ti-6A1-4V alloy endosseous dental implants after glow-discharge treatment: a preliminary report.

Inductively coupled argon plasma spectroscopic analysis was used to quantify titanium, aluminum, and vanadium corrosion products released by superficial layers of identically shaped commercially pure titanium and Ti-6A1-4V alloy dental implants. Halves of each of two originally sterile groups were analyzed directly from the manufacturer's packaging and the other halves received glow-discharge treatment prior to their corrosion assay. The implants were incubated in pH 3 modified saline solution and were analyzed after 2- and 12-week corrosion periods. Implants treated with glow discharge showed statistically significant reduction in the amounts of corrosion products released, apparently as a result of glow-discharge-produced surface oxides of greater passivity than originally present.

Aluminum↗
PubMed1992

[Carbon monoxide poisoning. Report of 13 cases].

From November 1990 to February 1991 was had, in the Emergency Unit of Clinical University Hospital San Carlos, Madrid, 13 documented cases of intoxication due to Carbon Monoxide (CO), in patients with unspecific cephalalgia and asthenia and a possible CO source (total 19 affected people living together, because some of them did not came to hospital to consult). We consider that CO intoxication shall be always be beared in mind when doing the diagnosis at the Emergency Unit, especially during winter months, and that appropriate resources should be available to perform promptyl the analytical confirmation.

Adolescent↗
PubMed1991

Acetylator polymorphism in human colorectal carcinoma.

Acetylator phenotype has been determined using sulfamethazine in 109 patients histologically diagnosed with colorectal carcinoma (resected in 74 patients by the time of the study) and in 96 age-matched controls. Fifty-five % of patients and 58.3% of controls were classified as slow acetylators (chi 2 = 0.11, not significant). No differences were observed in the distribution of acetylator phenotype when analyzing separately male and female, surgically treated and untreated, and colonic and rectal carcinoma patients. We conclude that acetylator polymorphism is not a genetic trait related to the risk of developing colorectal carcinoma in human beings.

Acetylation↗