Browsing by Autor "Elfride Balanza"

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Aminothiol Multidentate Chelators against Chagas Disease
(Elsevier BV, 2000) Eric Deharo; Mark Loyevsky; Christy S. John; Elfride Balanza; Grace Ruiz; Victoria Muñoz; Victor R. Gordeuk
Antiprotozoal activity of Jatrogrossidione from Jatropha grossidentata and Jatrophone from Jatropha isabellii 
(Wiley, 1996) Guillermo Schmeda‐Hirschmann; Iván Razmilic; Michel Sauvain; Christian Moretti; Verónica Francisca Loewe Muñoz; E. Ruiz; Elfride Balanza; Alain Fournet
The activity of jatrogrossidione, the main diterpene of Jatropha grossidentata and jatrophone from Jatropha isabellii was determined against Leishmania and Trypanosoma cruzi strains in vitro as well as against Leishmania amazonensis in vivo. Jatrogrossidione showed a strong in vitro leishmanicidal and trypanocidal activity with IC100 of 0.75 and 1.5–5.0 μg/mL, respectively. Under similar conditions, the IC100 of glucantime, ketoconazole and pentamidine towards Leishmania strains were >100, 50–100 and 1 μg/mL, respectively. The IC50 of jatrogrossidione was <0.25 μg/mL against amastigote forms of Leishmania infecting macrophages, with toxicity at concentrations higher than 0.5 μg/mL. BALB/c mice infected with L. amazonensis strain PH 8 were treated 24 h after infection with jatrogrossidione and jatrophone for 13 consecutive days. Jatrophone at 25 mg/kg/day subcutaneously administered was significantly active (p<0.05) against the virulent strain PH 8 of L. amazonesis; it was more active than Glucantime at 112 mg Sbv per kg/day. Subcutaneous administration of jatrophone, however, proved to be too toxic under our assay conditions. Assays of single local treatment on the footpad infection 2 weeks after inoculation of L. amazonensis indicated that jatrogrossidione and jatrophone were inactive at the selected doses.
Antiprotozoal activity of Jatrogrossidione from Jatropha grossidentata and Jatrophone from Jatropha isabellii
(Wiley, 1996) Guillermo Schmeda‐Hirschmann; Iván Razmilic; Michel Sauvain; Christian Moretti; Verónica Francisca Loewe Muñoz; E. Ruiz; Elfride Balanza; A. Fournet
The activity of jatrogrossidione, the main diterpene of Jatropha grossidentata and jatrophone from Jatropha isabellii was determined against Leishmania and Trypanosoma cruzi strains in vitro as well as against Leishmania amazonensis in vivo. Jatrogrossidione showed a strong in vitro leishmanicidal and trypanocidal activity with IC100 of 0.75 and 1.5–5.0 μg/mL, respectively. Under similar conditions, the IC100 of glucantime, ketoconazole and pentamidine towards Leishmania strains were >100, 50–100 and 1 μg/mL, respectively. The IC50 of jatrogrossidione was <0.25 μg/mL against amastigote forms of Leishmania infecting macrophages, with toxicity at concentrations higher than 0.5 μg/mL. BALB/c mice infected with L. amazonensis strain PH 8 were treated 24 h after infection with jatrogrossidione and jatrophone for 13 consecutive days. Jatrophone at 25 mg/kg/day subcutaneously administered was significantly active (p<0.05) against the virulent strain PH 8 of L. amazonesis; it was more active than Glucantime at 112 mg Sbv per kg/day. Subcutaneous administration of jatrophone, however, proved to be too toxic under our assay conditions. Assays of single local treatment on the footpad infection 2 weeks after inoculation of L. amazonensis indicated that jatrogrossidione and jatrophone were inactive at the selected doses.
Expression of lactate dehydrogenase A and B genes in different tissues of rats adapted to chronic hypobaric hypoxia
(Wiley, 2003) Fabrice Rossignol; Magali Solares; Elfride Balanza; J Coudert; Eric Clottes
Lactate dehydrogenase (LDH) is a tetramer made up of two different subunits A and B. In cellular models, severe hypoxia increases LDH A gene expression whereas LDH B gene does not exhibit any regulation. The aim of our work was to characterise LDH expression in different tissues of rats bred at high altitude. For this purpose, we chose a Sprague-Dawley rat strain adapted to chronic hypoxia in La Paz (3700 m), Bolivia. Two normoxic control groups were bred at low altitude in Clermont-Ferrand (350 m), France, one group was ad libitum with free access to food and water as was the hypoxic one, and the second normoxic group was nourished with the food intakes measured for the animals from La Paz. We measured total LDH specific activity, isoform distribution and LDH A and B mRNA amounts in three skeletal muscles (soleus, extensor digitorum longus (EDL), plantaris), heart and brain. Our study demonstrates that, unlike what has been shown in cellular models under severe hypoxia, LDH A gene is not systematically up-regulated in tissues of rats living at high altitude. Furthermore, chronic hypoxia limits LDH B gene transcription or its mRNA stability in both soleus and EDL. These regulations occur at various molecular levels like gene transcription, mRNA stabilisation or translation and protein stability, depending on the tissue studied, and are partly attributed to caloric restriction provoked by high altitude. These data provide insight into LDH gene expression underlying the diverse and complex tissue-specific response to chronic hypoxia.
Hypoglycemia and the Origin of Hypoxia-Induced Reduction in Human Fetal Growth
(Public Library of Science, 2009) Stacy Zamudio; Tatiana Torricos; Ewa Fik; Maria Oyala; Lourdes Echalar; Janet Pullockaran; Emily Tutino; Brittney Martin; Sonia Belliappa; Elfride Balanza
Our results support that preferential anaerobic consumption of glucose by the placenta at high altitude spares oxygen for fetal use, but limits glucose availability for fetal growth. Thus reduced fetal growth at high altitude is associated with fetal hypoglycemia, hypoinsulinemia and a trend towards lactacidemia. Our data support that placentally-mediated reduction in glucose transport is an initiating factor for reduced fetal growth under conditions of chronic hypoxemia.
The frequency of lactase phenotypes in Aymara children.
(BMJ, 1985) Elfride Balanza; Gonzalo Taboada
A total of 122 apparently healthy Bolivian Aymara-mixed children ranging in age from 2 to 12 years were tested for lactose absorption using the standard lactose tolerance test with blood glucose determination. Analysing the sample according to the age of the probands, we found an increased age related frequency of lactose malabsorption showing final percentages of 55% in the 2 to 5 years group, 57.4% in the 6 to 10 years group, and 77.4% in the 11 to 15 years group.
Trypanocidal Withanolides and Withanolide Glycosides from Dunalia brachyacantha
(American Chemical Society, 2001) José A. Bravo B.; Michel Sauvain; Alberto Gimenez T.; Elfride Balanza; Laurent Sérani; Olivier Laprévôte; Georges Massiot; Catherine Lavaud
Two new withanolide glycosides, (20R,22R)-O-(3)-alpha-L-rhamnopyranosyl(1-->4)-beta-D-glucopyranosyl-1 alpha,12 beta-diacetoxy-20-hydroxywitha-5,24-dienolide (3) and (20R,22R)-O-(3)-beta-D-xylopyranosyl(1-->3)-[beta-D-xylopyranosyl(1-->4)]-beta-D-glucopyranosyl-1 alpha-acetoxy-12 beta,20-dihydroxywitha-5,24-dienolide (4), were isolated from the leaves and root of Dunalia brachyacantha. Their aglycones, (20R,22R)-1 alpha,12 beta-diacetoxy-3 beta,20-dihydroxywitha-5,24-dienolide (or 1 alpha,12 beta-diacetyldunawithagenine) and (20R,22R)-1 alpha-acetoxy-3 beta,12 beta,20-trihydroxywitha-5,24-dienolide (or 1 alpha-acetyl-12 beta-hydroxydunawithagenine), are novel. The known 18-acetoxywithanolide D (1) and 18-acetoxy-5,6-deoxy-5-withenolide D (2) were also isolated from the leaves. These last two compounds were shown to be responsible for the trypanocidal, leishmanicidal, and bactericidal activities manifested by the crude ethanolic extract. The structures were deduced from spectroscopic data and on the basis of chemical evidence.
Variation of leishmanicidal activity in four populations of Urechites andrieuxii
(Elsevier BV, 2003) Manuel Jesús Chan-Bacab; Elfride Balanza; Eric Deharo; Victoria Muñoz; Rafael Durán Garcı́a; Luis M. Peña-Rodrı́guez
Where the O2goes to: preservation of human fetal oxygen delivery and consumption at high altitude
(Wiley, 2008) Lucrecia Postigo; Gladys Heredia; Nicholas P. Illsley; Tatiana Torricos; Caitlin Dolan; Lourdes Echalar; Wilma Téllez; Iván Maldonado; Michael Brimacombe; Elfride Balanza
Fetal growth is decreased at high altitude (> 2700 m). We hypothesized that variation in fetal O(2) delivery might account for both the altitude effect and the relative preservation of fetal growth in multigenerational natives to high altitude. Participants were 168 women of European or Andean ancestry living at 3600 m or 400 m. Ancestry was genetically confirmed. Umbilical vein blood flow was measured using ultrasound and Doppler. Cord blood samples permitted calculation of fetal O(2) delivery and consumption. Andean fetuses had greater blood flow and oxygen delivery than Europeans and weighed more at birth, regardless of altitude (+208 g, P < 0.0001). Fetal blood flow was decreased at 3600 m (P < 0.0001); the decrement was similar in both ancestry groups. Altitude-associated decrease in birth weight was greater in Europeans (-417 g) than Andeans (-228 g, P < 0.005). Birth weight at 3600 m was > 200 g lower for Europeans at any given level of blood flow or O(2) delivery. Fetal haemoglobin concentration was increased, decreased, and the fetal / curve was left-shifted at 3600 m. Fetuses receiving less O(2) extracted more (r(2) = 0.35, P < 0.0001). These adaptations resulted in similar fetal O(2) delivery and consumption across all four groups. Increased umbilical venous O(2) delivery correlated with increased fetal O(2) consumption per kg weight (r(2) = 0.50, P < 0.0001). Blood flow (r(2) = 0.16, P < 0.001) and O(2) delivery (r(2) = 0.17, P < 0.001) correlated with birth weight at 3600 m, but not at 400 m (r(2) = 0.04, and 0.03, respectively). We concluded that the most pronounced difference at high altitude is reduced fetal blood flow, but fetal haematological adaptation and fetal capacity to increase O(2) extraction indicates that deficit in fetal oxygen delivery is unlikely to be causally associated with the altitude- and ancestry-related differences in fetal growth.