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Biomedical subjects

M Araya

Publications and source records attributed to M Araya.

At least 19 recordsLinked to original sources
PubMed2006

Erythrocyte CuZn superoxide dismutase activity is decreased in iron-deficiency anemia.

Iron and copper are essential microminerals that are intimately related. The present study was performed to determine the effect of iron-deficiency anemia (IDA) and treatment with iron on laboratory indicators of copper status. Hemoglobin, mean corpuscular volume erythrocyte Zn protoporphyrin, serum ferritin, serum copper, serum ceruloplasmin, and erythrocyte CuZn-superoxide dismutase (SOD) activity were studied in 12 adult women with IDA before and after iron treatment for 60-90 d (100 mg/d Fe, as ferric polymaltose) and in 27 women with normal iron status. Prior to treatment with iron, serum copper and ceruloplasmin were not different between the groups and treatment with iron did not affect these measures. IDA women, before and after treatment with iron, presented a 2.9- and 2-fold decrease in erythrocyte CuZn-SOD activity compared to women with normal iron status (p < 0.001). Treatment with iron increased erythrocyte CuZn-SOD activity of the IDA group; however, this change was not statistically significant. In conclusion, CuZn-SOD activity is decreased in IDA. Measurement of this enzyme activity is not useful for evaluating copper nutrition in iron-deficient subjects.

Adult↗
PubMed2005

Upper limits on a stochastic background of gravitational waves.

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of omega0 < 8.4 x 10(-4) in the 69-156 Hz band is approximately 10(5) times lower than the previous result in this frequency range.

Journal Article↗
PubMed2005

Limits on gravitational-wave emission from selected pulsars using LIGO data.

We place direct upper limits on the amplitude of gravitational waves from 28 isolated radio pulsars by a coherent multidetector analysis of the data collected during the second science run of the LIGO interferometric detectors. These are the first direct upper limits for 26 of the 28 pulsars. We use coordinated radio observations for the first time to build radio-guided phase templates for the expected gravitational-wave signals. The unprecedented sensitivity of the detectors allows us to set strain upper limits as low as a few times 10(-24). These strain limits translate into limits on the equatorial ellipticities of the pulsars, which are smaller than 10(-5) for the four closest pulsars.

Journal Article↗
PubMed2005

Prebiotic ingestion does not improve gastrointestinal barrier function in burn patients.

Prebiotics increase intestinal levels of health-promoting bacteria implicated in decreasing pathogen colonization, stimulating immune functions and stabilizing gut barrier functions, parameters which are altered in burn patients. We propose that regular intake of a prebiotic, oligofructose (OF), might help to improve the altered gastrointestinal (GI) permeability observed in burn patients. A randomized, double-blind, controlled clinical trial was carried out in 41 burn patients (mean burn surface area=17.1+/-8.2%) who ingested daily 6 g of oligofructose (OF group) or sucrose as placebo (Control group) during 15 days. Gastrointestinal permeability to sucrose and lactulose/mannitol (L/M) was evaluated on days 1 (before treatment) 3, 7, 14 and 21. A permeability test was also performed in 18 healthy subjects as controls. Thirty-one patients completed the protocol (dropout rate=24.4%). Healthy subjects had a basal sucrose excretion of 21.3 mg (14.0-32.5 mg) and a basal L/M ratio of 0.017% (0.009-0.022%). Sucrose excretion increased 5-fold and L/M ratio 4.4-fold in burn patients on day 1 and these high levels of marker excretion decreased significantly throughout the study (p=0.016 and 0.000001, respectively). No differences between the OF and Control groups were observed for sucrose excretion or L/M ratio. In conclusion, the normalization of gastrointestinal permeability is not accelerated by prebiotic intake.

Adult↗
PubMed2004

Health and aesthetic impacts of copper corrosion on drinking water.

Traditional research has focused on the visible effects of corrosion--failures, leaks, and financial debits--and often overlooked the more hidden health and aesthetic aspects. Clearly, corrosion of copper pipe can lead to levels of copper in the drinking water that exceed health guidelines and cause bitter or metallic tasting water. Because water will continue to be conveyed to consumers worldwide through metal pipes, the water industry has to consider both the effects of water quality on corrosion and the effects of corrosion on water quality. Integrating four key factors--chemical/biological causes, economics, health and aesthetics--is critical for managing the distribution system to produce safe water that consumers will use with confidence. As technological developments improve copper pipes to minimize scaling and corrosion, it is essential to consider the health and aesthetic effects on an equal plane with chemical/biological causes and economics to produce water that is acceptable for public consumption.

Copper↗
PubMed2002

Role of thymidine phosphorylase and dihydropyrimidine dehydrogenase in tumour progression and sensitivity to doxifluridine in gastric cancer patients.

This study was designed to investigate the role of thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) on tumour progression and sensitivity to 5'-deoxy-5-fluorouridine (5'-DFUR). Tumour tissue was obtained from surgically resected samples from 93 patients with primary gastric cancer. Tumour TP and DPD expression levels were determined by the enzyme-linked immunosorbent assay (ELISA) system and compared with several clinicopathological factors and in vitro sensitivity to 5'-DFUR. DPD showed no correlation with any clinicopathological factors. However, the TP level was significantly correlated with the depth of tumour, lymphatic invasion and venous invasion. In comparison with 5'-DFUR sensitivity, there was a weak inverse correlation between the DPD level and the sensitivity to 5'-DFUR (r(s)=-0.361). Furthermore, the TP/DPD ratio showed a significant correlation with 5'-DFUR sensitivity (r(s)=0.634). In a subgroup of patients with postoperative 5'-DFUR administration, the survival rate was significantly better in patients with a high TP/DPD ratio (n=8) than in those with low TP/DPD ratio (n=14) (P=0.0140). These results suggest that sensitivity to 5'-DFUR is predictable by measurement of both TP and DPD levels.

Adult↗
PubMed2001

Lifetime events and posttraumatic stress disorder in 4 postconflict settings.

CONTEXT: Little is known about the impact of trauma in postconflict, low-income countries where people have survived multiple traumatic experiences. OBJECTIVE: To establish the prevalence rates of and risk factors for posttraumatic stress disorder (PTSD) in 4 postconflict, low-income countries. DESIGN, SETTING, AND PARTICIPANTS: Epidemiological survey conducted between 1997 and 1999 among survivors of war or mass violence (aged >/=16 years) who were randomly selected from community populations in Algeria (n = 653), Cambodia (n = 610), Ethiopia (n = 1200), and Gaza (n = 585). MAIN OUTCOME MEASURE: Prevalence rates of PTSD, assessed using the PTSD module of the Composite International Diagnostic Interview version 2.1 and evaluated in relation to traumatic events, assessed using an adapted version of the Life Events and Social History Questionnaire. RESULTS: The prevalence rate of assessed PTSD was 37.4% in Algeria, 28.4% in Cambodia, 15.8% in Ethiopia, and 17.8% in Gaza. Conflict-related trauma after age 12 years was the only risk factor for PTSD that was present in all 4 samples. Torture was a risk factor in all samples except Cambodia. Psychiatric history and current illness were risk factors in Cambodia (adjusted odds ratio [OR], 3.6; 95% confidence interval [CI], 2.3-5.4 and adjusted OR,1.6; 95% CI, 1.0-2.7, respectively) and Ethiopia (adjusted OR, 3.9; 95% CI, 2.0-7.4 and adjusted OR, 1.8; 95% CI, 1.1-2.7, respectively). Poor quality of camp was associated with PTSD in Algeria (adjusted OR, 1.8; 95% CI, 1.3-2.5) and in Gaza (adjusted OR, 1.7; 95% CI, 1.1-2.8). Daily hassles were associated with PTSD in Algeria (adjusted OR, 1.6; 95% CI, 1.1-2.4). Youth domestic stress, death or separation in the family, and alcohol abuse in parents were associated with PTSD in Cambodia (adjusted OR, 1.7; 95% CI, 1.1-2.6; adjusted OR, 1.7; 95% CI, 1.0-2.8; and adjusted OR, 2.2; 95% CI, 1.1-4.4, respectively). CONCLUSIONS: Using the same assessment methods, a wide range of rates of symptoms of PTSD were found among 4 low-income populations who have experienced war, conflict, or mass violence. We identified specific patterns of risk factors per country. Our findings indicate the importance of contextual differences in the study of traumatic stress and human rights violations.

Adult↗
PubMed2001

Nausea threshold in apparently healthy individuals who drink fluids containing graded concentrations of copper.

Ingestion of drinking water with a high copper content may induce acute gastrointestinal effects, mainly nausea and vomiting, rarely diarrhea and abdominal pain. The objectives of this study were to define nausea threshold in apparently healthy adult volunteers who received graded concentrations of copper and to explore how individual thresholds were modified by delivering copper in an orange-flavored drink. Sixty-one healthy subjects received 200 mL of a copper-containing solution in purified water, at concentrations 0, 2, 4, 6, 8, 10, and 12 mg/L, as copper sulfate, in random order. Nausea threshold concentration for first response was established and then this threshold was confirmed. Subsequently, following the same design, subjects received the same copper concentrations (up to 12 mg/L), delivered in an orange-flavored drink, starting at the confirmed threshold concentration found in water. Mild nausea shortly after ingestion of copper-containing water was the most frequent finding (33/61 subjects), starting at 4 mg/L; vomiting was observed in 7 individuals, starting at 6 mg/L. The NOEL for copper in purified water was 2 and 4 mg/L for nausea and vomiting, respectively. When copper was provided as an orange-flavored drink, 11 subjects (18%) reported nausea, starting at 8 mg Cu/L, and no subjects vomited up to 12 mg Cu/L. It is concluded that after consumption of copper in purified water, the NOEL is 2 mg Cu/L and the LOAEL 4 mg Cu/L for nausea, while tolerable intake is between 2 and 4 mg Cu/L in water depending on whether apparent or confirmed nausea is used as the criterion to define critical effects.

Administration, Oral↗
PubMed2001

Determination of an acute no-observed-adverse-effect level (NOAEL) for copper in water.

A prospective, double-blind controlled study was designed to determine the acute no-observed-adverse-effect level (NOAEL) of nausea in an apparently healthy population of 179 individuals who drank copper-containing water as the sulfate salt. Subjects were recruited at three different international sites and given a blind, randomly selected dose (0, 2, 4, 6, or 8 mg Cu/L) in a bolus of 200 ml (final total copper dose was equivalent to 0, 0.4, 0.8, 1.2, and 1.6 mg) once weekly over a consecutive 5-week period. Gastrointestinal (GI) symptoms of nausea, abdominal pain, vomiting, or diarrhea were screened for a period of up to 24 h. Nausea was the most frequently reported effect and was reported within the first 15 min of ingestion. For the combined trisite population (n=179), 8, 9, 14, 25, and 44 subjects responded positively to one or more GI symptoms at 0, 2, 4, 6, and 8 mg Cu/L, respectively. Analysis of the data demonstrated a clear dose response to the combined positive GI effects and to nausea alone. Statistically significant greater reporting of effects occurred at 6 and 8 mg Cu/L. Therefore, an acute NOAEL and lowest-observed-adverse-effect level of 4 and 6 mg Cu/L (0.8 and 1.2 mg Cu), respectively, were determined in drinking water for a combined international human population.

Adult↗
PubMed2001

Effect of acute copper exposure on gastrointestinal permeability in healthy volunteers.

In vitro studies indicate that treating cells with copper results in alteration of tight junction permeability. In humans, ingestion of a single bolus of up to 10 mg Cu/L (as copper sulfate) causes nausea and vomiting in approximately 20 and 5% of the volunteers, respectively. To understand better the gastric and intestinal effects of copper, in this study we evaluated in asymptomatic volunteers (1) the effects of acute copper ingestion on gastric and intestinal permeability and (2) whether the appearance of gastrointestinal symptoms is associated with changes in mucosal permeability. Thirty-one asymptomatic subjects were assessed in a randomized, double-blind, crossover study that included two permeability tests, one after ingesting 200 ml distilled water and the other after ingesting 200 ml water containing 10 mg Cu/L (as copper sulfate). Fifteen minutes after ingestion subjects drank a second solution containing 40 g sucrose, 7.5 g lactulose, and 2 g mannitol, and urine was collected for 5 hr. Sugar concentrations were determined by gas chromatography. Symptoms during the trials were recorded in self-administered questionnaires. Ingestion of the 10 mg/L copper solution significantly increased gastric permeability to sucrose [20.8 (11.8-73.4) vs 28.4 (16.6-113.9) mg, respectively; P = 0.0064] but did not change intestinal permeability to lactulose/mannitol [0.87 (0.53-2.06) vs 1.17 (0.58-2.39)%, respectively; P = 0.18]. Gastrointestinal symptoms were reported during both the basal and the experimental conditions, but after copper ingestion they increased to 22.6% of the subjects and were significantly more intense than under basal conditions (P = 0.047). However, changes in permeability were not related to the appearance of symptoms. These results indicate that acute oral exposure to 10 mg Cu/L exerts an effect on gastric but not intestinal mucosa, reducing the gastric mucosal barrier capacity, independently of the appearance of gastrointestinal symptoms.

Adult↗
PubMed2001

Acute nutritional and intestinal changes after pelvic radiation.

OBJECTIVE: Pelvic radiotherapy induces acute small bowel injury but its effects on nutritional status are unknown. The objective of this study was to prospectively evaluate nutritional, functional and morphologic intestinal changes, after radiotherapy. METHODS: Fifteen patients were studied before and after pelvic irradiation. A clinical, nutritional and routine clinical laboratory assessment was performed. Nutritional parameters included dietary recall, subjective global assessment, anthropometric measurements (body mass index, skinfold thickness at four sites and circumferences of arm, waist and hip), hand grip strength, indirect calorimetry and Dual Energy X-ray absortiometry (DEXA). Intestinal parameters included permeabilty to sugars (assessed by lactulose and mannitol urinary excretion), intestinal transit time (measured by hydrogen breath test after ingestion of lactulose) and jejunal biopsies. RESULTS: Thirteen patients presented diarrhea during radiation therapy. After five weeks, intestinal permeability increased, while intestinal transit time decreased. The second biopsy showed hypertrophy of villae and crypts. Simultaneously, patients lost weight at the expense of fat free mass. Resting energy expenditure was elevated prior to treatment and declined after five weeks. Changes in caloric ingestion were not significant. CONCLUSIONS: Our results indicate that pelvic radiation induces a loss of fat free mass along with intestinal morphologic and functional changes.

Adult↗
PubMed2001

Determination of the taste threshold of copper in water.

Copper effects on human health represent a relevant issue in modern nutrition. One of the difficulties in assessing the early, acute effects of copper ingested via drinking water is that the taste of copper may influence the response and the capacity to taste copper in different waters is unknown. The purpose of the study was to determine the taste threshold of copper in different types of water, using soluble and insoluble salts (copper sulfate and copper chloride). Copper-containing solutions (range 1.0-8.0 mg/l Cu) were prepared in tap water, distilled deionized water and uncarbonated mineral water. Sixty-one healthy volunteers (17-50 years of age), with no previous training for sensory evaluation, participated in the study. A modified triangle test was used to define the taste threshold value. The threshold was defined as the lowest copper concentration detected by 50% of the subjects assessed. To evaluate the olfactory input in the threshold value obtained, 15 of 61 subjects underwent a second set of triangle tests with the nose open and clamped, using distilled water with copper sulfate at a concentration corresponding to the individual's threshold. The taste threshold in tap water was 2.6 mg/l Cu for both copper sulfate and copper chloride. The corresponding values for distilled deionized water were 2.4 and 2.5 mg/l Cu for copper sulfate and copper chloride, respectively. In uncarbonated mineral water the threshold values were slightly higher, 3.5 and 3.8 mg/l Cu for copper sulfate and for copper chloride, respectively, which are significantly higher than those observed in tap and distilled waters (P < 0.01, Kruskal-Wallis test). The taste threshold did not change significantly when the nose was clamped. In conclusion, the median values for copper taste threshold were low, ranging between 2.4 and 3.8 mg/l Cu, depending on the type of water.

Adolescent↗
PubMed2001

Gastrointestinal effects associated with soluble and insoluble copper in drinking water.

The aim of this study was to determine whether total copper or soluble copper concentration is associated with gastrointestinal signs and symptoms. Forty-five healthy adult women (18-55 years of age), living in Santiago, Chile, ingested tap water with 5 mg/L of copper containing different ratios of soluble copper (copper sulfate) and insoluble copper (copper oxide) over a 9-week period. Three randomized sequences of the different copper ratios (0:5, 1:4, 2:3, 3:2, and 5:0 mg/L) were followed. Subjects recorded their water consumption and gastrointestinal symptoms daily on a special form. Mean water consumption was similar among groups. Serum copper levels, ceruloplasmin, and activities of liver enzymes were within normal limits. No differences were detected between the means of biochemical parameters at the beginning and at the end of the study. Twenty subjects presented gastrointestinal disturbances at least once during the study, 9 suffered diarrhea (with or without abdominal pain and vomiting), and the other 11 subjects reported abdominal pain, nausea, or vomiting. No differences were found in incidence of abdominal pain, nausea, vomiting, and diarrhea regardless of the ratio of copper sulfate to copper oxide. In conclusion, both copper sulfate (a soluble compound) and copper oxide (an insoluble compound) have comparable effects on the induction of gastrointestinal manifestations, implying that similar levels of ionic copper were present in the stomach.

Abdominal Pain↗
PubMed2001

[Celiac disease in adolescents and young adults. A challenge for gastroenterologists of children and adults].

BACKGROUND: Follow-up of celiac patients in Chile is often interrupted when adolescents are referred to adult gastroenterologists. AIM: To study the evolution of patients with celiac disease when they reach adolescence or young adulthood. PATIENTS AND METHODS: Current adherence to gluten-free diet and its relation to symptoms and circulating antiendomysial antibodies were evaluated in the 58 confirmed celiac patients older than 12 years of age controlled at 3 hospitals in Santiago. RESULTS: Mean age at the moment of this assessment was 17.8 +/- 5 years, 65.5% were women, 12.5% were at nutritional risk (-IDS) while 20% were overweight/obese. Although all patients declared themselves asymptomatic, a focused questionnaire revealed that 26% suffered some symptoms. Only 24.1% followed a strict gluten-free diet. Eight of 20 patients who ate gluten-containing diets had negative antiendomysial antibodies (EMA), three of whom turned positive within 6 to 9 months. In three of four (asymptomatic) cases that accepted a new jejunal biopsy, histology was abnormal. One patient who followed a strict diet had EMA (+) and normal histology. CONCLUSIONS: These results confirm that after childhood, symptoms abate significantly in celiac patients. The observed sensitivity and specificity of EMA makes necessary to maintain small intestinal biopsies as the gold standard for diagnosis and confirmation of the disease.

Adolescent↗
PubMed2000

Celiac disease in a Chilean population carrying Amerindian traits.

BACKGROUND: Although clinical manifestations of celiac disease may change throughout life, clinical, histologic, immunologic, and genetic studies show that there are incomplete forms of this condition, making it difficult to define the disease at a given moment. Because there is no information published in the Latin American-Amerindian population, this study was conducted to assess relations between these parameters in Chileans with celiac disease and their first-degree relatives. METHODS: Sixty-two persons with confirmed celiac disease (mean age, 17.9 +/- 5.1 years; 78.3% females) and 126 relatives (mean age, 27.9 +/- 17.2 years; 65.1% females) were evaluated. Clinical manifestations, antiendomysial antibodies (EMAs), and human leukocyte antigen (HLA) haplotypes were studied in patients. Additionally, jejunal biopsy specimens were assessed (light microscopy) in EMA-positive (EMA+) relatives. RESULTS: Of the patients, 24.1% adhered to a strict gluten-free diet; 26% were oligosymptomatic, and none were malnourished; 45% were EMA+; 13.8% who ingested gluten were EMA-negative (EMA-); one patient consuming a strict gluten-free diet was EMA+. The DQA1*0501 allele was present in the highest frequency (48%, P < 0.0005), whereas combinations of DQ8 were predominant. Of the relatives, 4.8% were EMA+; they had a significantly higher frequency of diarrhea, weight loss, and anorexia (P < 0.03); and all had abnormal histology in biopsy specimens. CONCLUSIONS: After childhood, celiac disease is oligosymptomatic and is often unrecognized by patients. Disease in 13.8% of patients and in 4.8% relatives appeared as incomplete forms of celiac disease. Predominance of DQ8 HLA haplotypes reflects the genetic Spanish-Mapuche heritage of this population.

Adolescent↗
PubMed2000

[Eosinophilic colitis caused by allergy to cow's milk protein].

Eosinophilic colitis is one of the clinical manifestations of allergy to cow's milk during the first year of life. We report a series of 9 infants who, under 9 months of age and while clinically well, presented rectal bleeding of variable magnitude, with or without diarrhea, shortly after a cow's milk-based formula was initiated (n = 6); yet, 3 cases received only breast feeding. Bleeding disappeared in all patients after milk withdrawal from the diet. Challenges were planned after 12 months of treatment; three patients have not yet reached this moment, 3 had a negative challenge at 12, 18 and 28 months of age and are on a complete diet, and 3 are still on cow's milk free diet because ingestion of milk at 12, 18 and 25 months still induced rectal bleeding. This series of patients gathered in 3 years, follows the trend reported in many countries that there is a relative increase of patients diagnosed with allergy conditions early in life.

Age of Onset↗