PubMed Health⌕ Search

Biomedical subjects

M Ruz

Publications and source records attributed to M Ruz.

At least 19 recordsLinked to original sources
PubMed2004

Association between aminolevulinate dehydrase genotypes and blood lead levels in children from a lead-contaminated area in Antofagasta, Chile.

Childhood environmental lead exposure in the city of Antofagasta, Chile, was generated by the accumulation of recently removed lead stores derived from mining activities for a long period of time. Susceptibility to harmful lead effects may be associated with polymorphisms of delta-aminolevulinic acid dehydratase (ALAD) because of the differential binding of lead to the codified proteins. We assessed the associations and possible interactions among the following variables: blood lead levels, ALAD genotypes, and distance to the source of lead contamination in Chilean children exposed to lead contamination in Antofagasta, Chile. Ninety-three children were recruited from schools located near a lead- contaminated area. Lead blood levels were measured by atomic absorption spectrophotometry. ALAD genotypes were determined by polymerase chain reaction and restriction fragment-length polymorphism analysis. The frequency of the ALAD-2 allele was estimated at 0.054. Children with the ALAD-2 genotype had higher blood lead levels than noncarriers (p = 0.06). As expected, blood lead levels were inversely correlated with the distance from lead stores. Interestingly, ALAD-2 carriers were more frequent within the area defined by a distance of 200 m from lead deposits (27%) than in areas >200 m (5%) away. Children living within a maximum distance of 200 m from the lead stores showed higher blood lead levels in ALAD-2 carriers (geometric mean = 16.4 microg/dl, range 6 to 27) than in noncarriers (geometric mean = 12.1 microg/dl, range 0 to 26) without achieving statistical significance (p = 0.13). A trend for higher blood lead levels in ALAD-2 carriers compared with ALAD-1 homozygous children has been observed. Because ALAD-2 frequency was higher in subjects living within 200 m from the lead deposits, we hypothesized that a long-term selective pressure against the presence of the ALAD-1 allele is the cause of the overrepresentation of the ALAD-2 allele in children living in proximity to the recently removed lead stores.

Child↗
PubMed2000

Leukapheresis components may be cryopreserved at high cell concentrations without additional loss of HPC function.

BACKGROUND: The aim of this study was to assess the feasibility of freezing mobilized peripheral blood progenitor cell (PBPC) components at higher cell concentrations than are classically recommended for bone marrow. This approach might have potential benefits, such as lower cost of processing and storage and less risk of the complications associated with the transfusion of large component volumes and large quantities of DMSO. STUDY DESIGN AND METHODS: In the first phase, small aliquots of 19 apheresis components were cryopreserved at standard and higher cell concentrations (Aliquots A and B, respectively). In the second phase, 21 apheresis components were split into two bags each and frozen at standard (Bag A) and high (Bag B) cell concentrations. The differences in viability, cloning efficiency, and nucleated cell recovery in Bags A and B were examined. Finally, the hematologic recovery of 10 patients who underwent autologous transplantation with PBPC components frozen at high cell concentrations was analyzed. RESULTS: The median cell concentration at freezing was 94 (57-100) x 10(6) per mL and 291 (220-467) x 10(6) per mL for Aliquots A and B, respectively, and 90.9 (45.4-92) x 10(6) per mL and 332 (171-582) x 10(6) per mL for Bags A and B, respectively. The viability was significantly lower in samples frozen at higher cell concentrations: 92 versus 83 percent (p = 0.001) and 87 versus 77 percent (p<0.001) for Aliquots and Bags A and B, respectively. Significant differences were not observed in the recovery of total nucleated cells (102 vs. 101% and 98 vs. 105%) or the cloning efficiency after thawing (13 vs. 16% and 27 vs. 23%) for Aliquots and Bags A and B, respectively. The time to granulocyte engraftment >0.5 x 10(9) per L and platelet engraftment >20 x 10(9) per L was 9 (8-11) and 10.5 (7-21) days, respectively. CONCLUSION: The cryopreservation of PBPC components at standard concentrations and 3.3 (1.8-6.2)-fold cell concentrations has no adverse effect on the function of HPCs after thawing.

Blood Preservation↗
PubMed1999

Low environmental selenium availability as an additional determinant for goiter in East Java, Indonesia?

Iodine deficiency, which is most visibly indicated by goiter, is highly prevalent in Indonesia. Since 1994, Indonesia has a decree that all salt used for human, livestock, and industry must be iodized. However, despite the increased distribution of iodized salt, pockets with significantly higher prevalence of goiter still remain. This situation may be consequence of selenium (Se) deficiency. This study aimed to assess the Se level in the environment of goiter prevalent areas. Five hundred eleven school children participated in this study. Goiter was measured using both ultrasound and palpation. Ninety-nine eggs were collected from free-living chicken in 11 villages, and the Se contents of egg yolk and egg white were determined by neutron activation analysis. In the villages studied, Se concentration in egg yolk ranged from 0.15 to 1.52 microg/g and in egg white from 0.18 to 2.97 microg/g. The prevalence of goiter measured by palpation ranged from 18.4% to 70% and by ultrasound from 0% to 100%. Because of the inconsistency of goiter rate measured by palpation and ultrasonography, the question remains whether low availability of Se in the environment might be an additional contributing factor for goiter.

Child↗
PubMed1999

Single and multiple selenium-zinc-iodine deficiencies affect rat thyroid metabolism and ultrastructure.

This study was conducted to evaluate the effects of single and combined deficiencies of Se, Zn and I on thyroid function in rats. Rats were fed amino acid-based diets for 6 wk starting from weaning. The diets contained either low or adequate amounts of these minerals. In addition to the control and control pair-fed groups, seven experimental groups were formed: Se deficient (Se-); I deficient (I-); Zn deficient (Zn-); Se and I deficient (Se-I-); Zn and I deficient (Zn-I-); Se and Zn deficient (Se-Zn); and Se, I and Zn deficient (Se-I-Zn-). Serum triiodothyronine (T3) was significantly lower than in controls in Zn-, Se-Zn- and Se-I- groups. Serum total thyroxine (T4) and free T4 were significantly lower and thyroid-stimulating hormone (TSH) greater in all iodine-deficient groups, regardless of Se or Zn status. Thyroid glutathione peroxidase activity was significantly reduced in Se- and Se-Zn- groups. Nevertheless, in the groups with a concurrent I deficiency, the activity of this enzyme was significantly greater than in controls. Severe alterations of the follicle cellular architecture, including signs compatible with apoptosis, were observed in the Zn- and Se-Zn- groups. These alterations appeared to be less severe when iodine deficiency was simultaneously present. Single and multiple deficiencies of Se, Zn and I have distinct effects on thyroid metabolism and structure.

Animals↗
PubMed1997

A 14-mo zinc-supplementation trial in apparently healthy Chilean preschool children.

Apparently healthy preschool children (46 boys, 52 girls) aged 27-50 mo from low socioeconomic conditions who attended daycare centers in Santiago participated in a 14-mo long double-blind zinc supplementation trial. Unlike most previous studies, no additional inclusion criteria such as short stature or slow growth rate were considered. Subjects were pair matched according to sex and age and randomly assigned to two experimental groups: the supplemented group, which received 10 mg Zn/d, and the placebo group. Selected anthropometric, clinical, dietary, biochemical, and functional indexes were determined at the beginning of the study and after 6 and 14 mo of intervention. Actual dietary zinc intake was 66% of the recommended dietary allowance. Height gain after 14 mo was on average 0.5 cm higher in the supplemented group (P = 0.10). The response, however, was different between sexes. Boys from the supplemented group gained 0.9 cm more than those in the placebo group (P = 0.045). No effect was seen in girls. Although no significant differences were observed in the rest of the variables studied, trends (0.05 < P < 0.10) in the supplemented group compared with the placebo group for increased midarm muscle area in boys, improved response to tuberculin, and reduced rates of parasite reinfestation were noted. We conclude that in preschool children of low socioeconomic status, zinc is a limiting factor in the expression of growth potential.

Administration, Oral↗
PubMed1995

Characterization of the regional distribution of selenium in Chile using selenium in hens' eggs as a monitor.

Regional distribution of selenium (Se) in Chile was investigated by using the concentration of Se in hens' eggs as a monitor. Forty-one locations along the entire length of the country were sampled. Average (+/- SD) egg-white Se content (mg/kg dry) was 0.79 +/- 0.41, range 0.22-2.23. Corresponding yolk Se values were, mean 0.81 +/- 0.43, (mg/kg dry) range 0.26-2.23. Locations grouped in five main areas, according to their geographic-climatic characteristics, showed significant differences regarding both egg-white Se and yolk Se. Analyzed dietary Se intake from two distinct areas reflected the trends observed in the Se content of egg fractions from such regions. These data support the utilization of the concentration of Se in hens' eggs as a useful monitor of dietary selenium consumed by selected populations.

Animals↗
PubMed1995

Alteration of circulating micronutrients with overt and occult infections in anaemic Guatemalan preschool children.

Clinical and laboratory data to define conditions of apparent health, localised infection or inapparent infection were available for 74 anaemic Guatemalan preschool children in the baseline phase of a clinical trial of the effect of iron and vitamin A on haematological status to be correlated with serum levels of four circulating micronutrients--iron, zinc, copper and retinol--known to be influenced by activation of the acute-phase reaction. Upon enrolment, only 29.7% of the children were free of all evidence of infection, 36.5% had one or more localised conditions detected on clinical examination, and 33.8% had an elevated white cell count and/or sedimentation rate, without localising features. These were classified as 'inapparent infections'. With respect to the healthy children, levels of iron, zinc, and retinol declined and copper generally increased in the four categories of clinical infections (acute respiratory infection, dermal infections, conjunctivitis, and 'other') but were also displaced in inapparent infections. Some activation of the acute-phase response in anaemic children may occur in the absence of clinical findings. Care must be taken in interpreting circulating micronutrient levels in relation to nutritional status in such population.

Acute-Phase Reaction↗
PubMed1993

Growth and body composition of periurban Guatemalan children in relation to zinc status: a cross-sectional study.

In a study of periurban Guatemalan school-children (89 males, 73 females) aged 81.5 +/- 7.0 mo (mean +/- SD), height, weight, arm circumference, and triceps-skinfold-thickness (TSF) measurements were examined in relation to plasma and hair zinc concentrations, plasma and red blood cell alkaline phosphatase activities, recognition thresholds for salt (RTS), delayed-cutaneous hypersensitivity response to seven recall skin test antigens, and cognitive measures. Children were stunted [median height-for-age (HA) Z score -1.49] but not wasted [median weight-for-height (WH) Z score 0.20], with median midarm muscle area (MAMA) and midarm-fat area (MAFA) Z scores of -0.57 and -0.35, respectively. Of the children, 63.5% of males and 44.1% of females had hair zinc < 1.68 mumol/g (P < 0.05); 12.3% of males and 1.5% of females had plasma zinc < 10.71 mumol/L (P < 0.05). Children with hair zinc < 1.68 mumol/g had higher (P < 0.05) medians for WA Z and WH Z scores, RTS, and phytic acid intake than did those with hair zinc > or = 1.68 mumol/g. Zinc status explained some of the variance in growth (HA, WA, and WH Z scores), body composition (MAFA Z scores), and taste acuity. Suboptimal zinc status arose partly from diets low in readily available zinc.

Aging↗
PubMed1993

Growth and body composition of periurban Guatemalan children in relation to zinc status: a longitudinal zinc intervention trial.

Changes in growth, body composition, and zinc indexes were evaluated after 25 wk in a double-blind zinc-supplementation study of 162 periurban Guatemalan children aged 81.5 +/- 7.0 mo (mean +/- SD). Children receiving the zinc supplement (10 mg Zn/d as amino acid chelate) for 90.1 +/- 9.2 d had higher mean fasting plasma zinc (16.2 +/- 2.9 vs 14.9 +/- 2.1 mumol/L, P < 0.01), a greater increase in median triceps skinfold Z score (0.50 vs 0.38, P < 0.05), and a smaller deficit in median midarm circumference (MAC) Z score (-0.03 vs -0.20, P < 0.05) compared with the placebo group. Initial hair zinc classified as < 1.68 and > 1.68 mumol/g was the only laboratory variable that explained some of the variance in final Z scores of midarm-muscle area (P < 0.05) and MAC (P < 0.01). Children responded to the zinc supplement with changes in indexes of body composition rather than growth.

Anthropometry↗
PubMed1993

The effect of zinc supplementation on parasitic reinfestation of Guatemalan schoolchildren.

One hundred thirty children (65-95 mo old) from a low-socioeconomic neighborhood of Guatemala City participated in a randomized, double-blind, controlled trial of zinc supplementation. One group received 10 mg Zn/d (n = 65) and the other group received a placebo (n = 65); 90 +/- 9.2 doses were given over 120-150 d. Stools were examined for prevalence and intensity of helminths and prevalence of protozoa at the beginning and end of the study. The initial prevalence was 42% for helminths and 18% for protozoa, with no differences between groups. Mebendazole was administered to all children, and protozoal infections were treated specifically at the beginning of the study. The reinfection rates were 17% (11 of 65) for helminths and 12.3% (8 of 65) for protozoa in the zinc group and 15% (10 of 65) and 10.7% (7 of 65), respectively, in the placebo group (P > 0.05). Analysis by specific parasites revealed no treatment effect. We conclude that neither plasma or hair zinc status nor oral zinc supplementation had an effect on parasite status in children.

Animals↗
PubMed1993

Preparation effects on tortilla mineral content in Guatemala.

We have previously reported that in Guatemala, the calcium, iron, and zinc contents of tortillas from rural areas are higher that that of tortillas from urban centers. This study examines variation in the calcium, iron, zinc and copper content of tortilla according to the implements used for making tortillas and inquires as to whether preparation effects mediate rural-urban variation in tortilla mineral content. Tortilla samples and information on how the tortillas were prepared were collected from the female heads of a total of 50 households from three rural, two semi-urban and one low income urban community. Samples of lime used for making tortillas were collected from 31 households. To grind masa, a hand mill was found to be used in some rural households whereas a motorized mill predominated in the semi-urban and urban areas. Most women used grinding stones called the "mano y metate" to further refine the texture of the masa. Tortillas prepared with the combined use of the hand mill and "mano y metate" had a significantly (p < 0.05) higher iron content. Use of the "mano y metate" was also associated with a significantly (p < 0.05) higher zinc content. These results suggest that the use of certain grinding implements may mediate rural-urban variation in tortilla iron and zinc content. The cooking surface, pot used for nixtamalization, source of water, and amount of lime used did not significantly account for variation in the content of these minerals.

Female↗
PubMed1992

Indices of iron and copper status during experimentally induced, marginal zinc deficiency in humans.

This study examined the effect of diet-induced, marginal zinc deficiency for 7 wks in 15 men (aged 25.3 +/- 3.3 yrs; mean +/- SD) on selected indices of iron and copper status. The regimen involved low-zinc diets based on egg albumin and soy protein with added phytate and calcium such that mean [phytate]/[Zn] and [phytate] X [Ca]/[Zn] molar ratios were 209 and 4116, respectively, for 1 wk, followed by 70 and 2000, respectively, for 6 wks. Subjects were then repleted with 30 mg Zn/d for 2 wks. Plasma copper, Cu,Zn-superoxide dismutase (Cu,Zn-SOD) activity in plasma and red blood cells (RBC), hemoglobin, hematocrit, and serum ferritin were determined weekly on fasting blood samples. Significant reductions (p less than 0.05) after 7 wks in RBC Cu,Zn-superoxide dismutase (49.5 +/- 7.2 vs 33.6 +/- 6.3 U/mg Hb) and serum ferritin (69.2 +/- 38.7 vs 53.8 +/- 33.7 micrograms/L) occurred; no comparable decline was noted for plasma Cu, hemoglobin, or hematocrit. Significant (p less than 0.05) but less consistent changes were also observed in plasma superoxide dismutase activity. None of the changes were associated with the decreases in plasma, urinary and hair zinc concentrations, and alkaline phosphatase activity in RBC membranes. Results indicate that the biochemical iron and copper status of the subjects was marginally impaired, probably from the dietary regimen that induced marginal zinc deficiency.

Adult↗
PubMed1992

Erythrocytes, erythrocyte membranes, neutrophils and platelets as biopsy materials for the assessment of zinc status in humans.

During a controlled zinc depletion-repletion study, fifteen men aged 25.3 (SD 3.3) years were fed on a low-Zn diet with high phytate:Zn and phytate x calcium:Zn molar ratios for 7 weeks, followed by a 2 week repletion period when 30 mg supplemental Zn/d was given. Changes in plasma, urine, and hair Zn concentrations, taste acuity, and cellular immune response confirmed the development of mild Zn deficiency. Zn concentrations in neutrophils, platelets, erythrocytes and erythrocyte membranes, mean platelet volume, and activities of alkaline phosphatase (EC 3.1.3.1) and alpha-D-mannosidase (EC 3.2.1.24) in neutrophils did not respond to changes in Zn status. In contrast, alkaline phosphatase activity in erythrocyte membranes showed a significant decline which was consistent in all subjects (nmol product formed/min per mg protein; baseline v. 7-week Zn depletion, 0.656 (SD 0.279) v. 0.506 (SD 0.230), at 7 weeks; P < 0.05); neutral phosphatase activity remained unchanged. Alkaline phosphatase activity in erythrocyte membranes may be a potential index of Zn status in humans.

Adult↗
PubMed1992

Mouth-to-anus transit-time predicts the severity of fecal water loss in acute dehydrating diarrhea.

The mouth-to-anus transit time was estimated in 24 young children admitted to an outpatient rehydration unit with acute dehydrating diarrheal disease by adding an oral fecal marker (brilliant blue) to the first draught of oral rehydration solution. Transit times ranged from 30 to 242 min. There was a highly significant (logarithmic) relationship between rate of fecal output and transit time (r = 0.74; p < 0.001). Three of 24 subjects could not be rehydrated orally, were declared treatment failures, and were hospitalized for intravenous therapy. All of them had had an initial transit time of less than 50 min, and constituted three of the four subjects with this rapid rate of transit. Thus, a rapid mouth-to-anus transit time had a 100% sensitivity to predict treatment failures and a 75% predictive accuracy for a "positive" test. Although our series is small, the findings suggest that fecal markers may be useful in remote areas to assist in the early detection of diarrheal episodes that cannot be managed by oral rehydration therapy.

Acute Disease↗
PubMed1991

Development of a dietary model for the study of mild zinc deficiency in humans and evaluation of some biochemical and functional indices of zinc status.

After a 1-wk baseline period, a dietary regimen was developed to induce mild zinc deficiency in 15 males (aged 25.3 +/- 3.3 y, mean +/- SD). The regimen consisted of 1 wk on a liquid diet containing 0.6 mg Zn/d and molar ratios of phytate to zinc (phy:Zn) and of phytate X calcium to zinc [(phy X Ca): Zn] of 209 and 4116, respectively, followed by 6 wk on a diet based on soy protein and egg albumin containing 4 mg Zn/d and with phy:Zn and (Ca X phy):Zn of 70 and 2000, respectively. Subjects were then repleted with 30 mg Zn/d for 2 wk. Fasting blood and urine samples were taken weekly. Changes were observed in mean plasma (mumol/L) and urinary zinc (mumol/d): baseline 97.0 +/- 10.9 and 8.0 +/- 2.7, depletion 80.1 +/- 13.4 and 4.3 +/- 2.3, and repletion 100.8 +/- 13.6 and 8.2 +/- 3.1, respectively (P less than 0.05); taste acuity (0.05 less than P less than 0.10); and cellular immune responses (P less than 0.05). Activities of plasma angiotensin-1-converting enzyme and acidic alpha-D-mannosidase were unchanged. Mild zinc deficiency was induced by the dietary regimen.

Adult↗
PubMed1990

Mineral excretion during acute, dehydrating diarrhea treated with oral rehydration therapy.

Twenty-four male Guatemalan children, aged 7 to 23 mo, suffering dehydration due to acute diarrhea were studied to assess their fecal endogenous losses of trace minerals zinc, iron, and copper while treated with oral rehydration therapy, either with standard or glycine-added solutions. Sodium and potassium excretions (from endogenous and exogenous sources) were also monitored. No statistically significant effect of glycine was observed on any of the minerals studied, although a tendency to higher output was seen with zinc. Median rates of fecal excretion of zinc, iron, and copper were 6.08, 6.33, and 1.61 micrograms/kg/h, respectively, whereas those for sodium and potassium were 11.2 and 9.7 mg/kg/h. All of the minerals' excretion showed significant linear correlations with fecal volume, r values were 0.47 (Zn), 0.64 (Fe), 0.77 (Cu), 0.98 (Na), and 0.97 (K). Mineral-mineral interactions also were evident, with such correlations in fecal excretion rates as: Zn versus Cu, r = 0.75; Zn versus Fe, r = 0.62; Fe versus Cu, r = 0.76.

Diarrhea↗