Plasmodium falciparum K13 expression associated with parasite clearance during artemisinin-based combination therapy.

BACKGROUND: Delayed parasite clearance and, consequently, reduced efficacy of artemisinin-based combination therapies have been linked with Plasmodium falciparum K13 gene SNPs in Southeast Asia. In Africa, significantly prolonged clearance has not yet been observed and the presently restricted variation in parasite clearance cannot be explained by K13 polymorphisms. OBJECTIVES: Our aim was to study the in vivo pfK13 transcriptional response in patients treated with artemether-lumefantrine and explore whether the pfk13 transcripts can explain the patients' parasite clearance outcomes. PATIENTS AND METHODS: A total of 47 Tanzanian children with microscopically confirmed uncomplicated P. falciparum malaria were hospitalized and received artemether-lumefantrine treatment (clinical trial ID: NCT00336375). RNA was extracted from venous blood samples collected before treatment initiation and at five more timepoints after treatment. cDNA was synthesized and pfk13 transcripts measured by real-time PCR. RESULTS: A wide range of pfk13 transcript variation was observed throughout all timepoints after artemether-lumefantrine treatment. Taking parasite clearance data together with the pfk13 transcripts profile, we observed a negative correlation inferring that pfk13 down-regulation is associated with longer parasite clearance time. CONCLUSIONS: The findings suggest that a reduced PfK13 transcriptional response may represent a first step towards artemisinin tolerance/resistance.

pfmdr1 amplification is related to increased Plasmodium falciparum in vitro sensitivity to the bisquinoline piperaquine.

The 4-aminoquinoline bisquinoline piperaquine is an important partner drug in one of the presently recommended artemisinin combination therapies. Recent clinical trials have confirmed its high efficacy in combination with dihydroartemisinin. Resistance to piperaquine alone has, however, been documented. Amplification in copy number of the Plasmodium falciparum multidrug resistance locus on chromosome 5, containing the pfmdr1 gene, has been shown to confer resistance to structurally unrelated antimalarials. Through the determination of the 50% inhibitory concentrations (IC(50)s) and IC(90)s for piperaquine and chloroquine in a set of 46 adapted P. falciparum cultures originating from the Thai-Burmese border, we have characterized the regions around the pfmdr1 gene and identified a significant association between the presence of pfmdr1 duplications and enhanced sensitivity to piperaquine (P = 0.005 for IC(50) and P = 0.002 for IC(90)) and chloroquine, reaching statistical significance at IC(90)s (P = 0.026). These results substantiate the potential importance of pfmdr1 copy number amplifications in the efficacy of the combination therapy piperaquine-dihydroartemisinin. It supports the rational use of 4-aminoquinolines and artemisinin-based compounds, as they independently select for mutually incompatible combinations of mutations.

Pharmacogenomics of CYP2A6, CYP2B6, CYP2C19, CYP2D6, CYP3A4, CYP3A5 and MDR1 in Vietnam.

AIM: The aim of this study was to obtain pharmacogenetic data in a Vietnamese population on genes coding for proteins involved in the elimination of drugs currently used for the treatment of malaria and human immunodeficiency virus/acquired immunodeficiency syndrome. METHOD: The main polymorphisms on the cytochrome P450 (CYP) genes, CYP2A6, CYP2B6, CYP2C19, CYP2D6, CYP3A4 and CYP3A5, and the multi-drug resistance 1 gene (MDR1) were genotyped in 78 healthy Vietnamese subjects. Pharmacokinetic metrics were available for CYP2A6 (coumarin), CYP2C19 (mephenytoin), CYP2D6 (metoprolol) and CYP3As (midazolam), allowing correlations with the determined genotype. RESULTS: In the CYP2 family, we detected alleles CYP2A6*4 (12%) and *5 (15%); CYP2B6*4 (8%), *6 (27%); CYP2C19*2 (31%) and *3 (6%); CYP2D6*4, *5, *10 (1, 8 and 44%, respectively). In the CYP3A family, CYP3A4*1B was detected at a low frequency (2%), whereas CYP3A5 *3 was detected at a frequency of 67%. The MDR1 3435T allele was present with a prevalence of 40%. Allele proportions in our cohort were compared with those reported for other Asian populations. CYP2C19 genotypes were associated to the S-4'-OH-mephenytoin/S-mephenytoin ratio quantified in plasma 4 h after intake of 100 mg mephenytoin. While CYP2D6 genotypes were partially reflected by the alpha-OH-metroprolol/metoprolol ratio in plasma 4 h after dosing, no correlation existed between midazolam plasma concentrations 4 h post-dose and CYP3A genotypes. CONCLUSIONS: The Vietnamese subjects of our study cohort presented allele prevalences in drug-metabolising enzymes that were generally comparable with those reported in other Asian populations. Deviations were found for CYP2A6*4 compared to a Chinese population (12 vs. 5%, respectively; P = 0.023), CYP2A6*5 compared with a Korean population (15 vs. <1%, respectively; P < 0.0001), a Malaysian population (1%; P < 0.0001) and a Chinese population (1%; P < 0.0001); CYP2B6*6 compared with a Korean population (27 vs. 12%; P = 0.002) and a Japanese population (16%; P = 0.021). Pharmacokinetic metrics versus genotype analysis reinforces the view that the predictive value of certain globally common variants (e.g. CYP2D6 single nucleotide polymorphisms) should be evaluated in a population-specific manner.

Cytogenetic analysis and description of the sexual chromosome determination system ZZ/ZW of species of the fish genus Serrapinnus (Characidae, Cheirodontinae).

Four populations of Serrapinnus notomelas and one population of Serrapinnus sp.1, both belonging to the subfamily Cheirodontinae, were analyzed by Giemsa and silver nitrate impregnation techniques. We found 2n = 52 chromosomes for all populations, with interspecific differences in the karyotype formula; S. notomelas showed 16 m + 22 sm + 10 st + 4a, with fundamental number (FN) = 100 for males, and 16 m + 23 sm + 10 st + 3a, with FN = 101 for females. Serrapinnus sp.1 had 8m + 16 sm + 4 st + 24 a, with FN = 80 for males, and 8m + 15 sm + 4 st + 25 a, with FN = 79 for females. The difference in FN for the two sexes is due to a pair of heteromorphic chromosomes in the females of both species, which characterizes a ZZ/ZW-type mechanism of chromosome sexual determination. Interspecies differences were also found in nucleolus organizer regions (NORs). A simple NOR system was detected in three of four S. notomelas populations, while Serrapinnus sp.1 had two chromosome pairs with NOR. Although S. notomelas and Serrapinnus sp.1 have the same diploid number, differences in the karyotype structure indicate that these are different species. Apparently there was pericentric inversion during the karyotype evolution of these species.

Cytogenetic analysis and description of the sexual chromosome determination system ZZ/ZW of species of the fish genus Serrapinnus (Characidae, Cheirodontinae)

Four populations of Serrapinnus notomelas and one population of Serrapinnus sp.1, both belonging to the subfamily Cheirodontinae, were analyzed by Giemsa and silver nitrate impregnation techniques. We found 2n = 52 chromosomes for all populations, with interspecific differences in the karyotype formula; S. notomelas showed 16m + 22sm + 10st + 4a, with fundamental number (FN) = 100 for males, and 16m + 23sm + 10st + 3a, with FN = 101 for females. Serrapinnus sp.1 had 8m + 16sm + 4st + 24a, with FN = 80 for males, and 8m + 15sm + 4st + 25a, with FN = 79 for females. The difference in FN for the two sexes is due to a pair of heteromorphic chromosomes in the females of both species, which characterizes a ZZ/ZW-type mechanism of chromosome sexual determination. Interspecies differences were also found in nucleolus organizer regions (NORs). A simple NOR system was detected in three of four S. notomelas populations, while Serrapinnus sp.1 had two chromosome pairs with NOR. Although S. notomelas and Serrapinnus sp.1 have the same diploid number, differences in the karyotype structure indicate that these are different species. Apparently there was pericentric inversion during the karyotype evolution of these species.

Caracterizaçäo da microbiota psicrotrófica deteriorativa em carcaças de frango sob efeito de soluçöes sanificadoras, na linha de produçäo de abatedouros industriais / Characterization of spoilage microorganisms in broiler carcasses, under effect of sanitizer solutions

Pesquisou-se a microbiota psicrotrótica deteriorativa (proteolítica e lipolítica) da carne de frango, sob efeito de tratamentos de pré-resfriamento em soluçöes de 50 e 70 ppm de cloro livre e em soluçöes de ácido acético 0,2M em pH=3,5 e 5,0, em dois abatedouros de duas regiöes produtoras do Estado de Minas Gerais. Houve predominância dos seguintes gêneros: Pseudomonas, 35,75 por cento, Acinetobacter, 21,71 por cento, Moraxella, 21,60 por cento, Achromobacter, 21,40 por cento, Alcaligenes, 15,60 por cento, Alteromonas, 13,30 por cento e Flavobacterium, 10,0 por cento, cujas freqüências foram diferentemente distribuídas para as duas regiöes estudadas

Clinical and arteriographic characterization of patients with unstable angina without critical coronary arterial narrowing (from the TIMI-IIIA Trial).

Previous studies have reported that some patients presenting with unstable angina are found at coronary angiography to have no critical coronary stenosis. This study evaluated the clinical presentation and arteriographic findings in patients enrolled in the Thrombolysis in Myocardial Ischemia (TIMI-IIIA) trial, which assessed the effect of tissue-type plasminogen activator added to conventional therapy on the coronary arteriographic findings in patients presenting with ischemic pain at rest. Three hundred ninety-one patients were enrolled in the TIMI-IIIA trial and underwent coronary arteriography within 12 hours of enrollment. Fifty-three patients (14%) had no luminal diameter stenosis of a major coronary artery of > or = 60% on the baseline arteriogram. Compared with patients with unstable angina with an identifiable culprit lesion, patients without critical coronary obstruction were more likely to be women and non-white and less likely to have ST-segment deviation on the presenting electrocardiogram. Arteriography in such patients revealed no visually detectable coronary stenosis in half of the group; the remaining patients had noncritical coronary narrowing (i.e., < 60% luminal diameter stenosis) without morphologic features (ulceration or thrombus) suggestive of unstable or active coronary plaque. Nearly one third of the patients without critical coronary stenosis had impaired angiographic filling, suggesting a possible pathophysiologic role for coronary microvascular dysfunction. These patients with unstable angina and no critical coronary obstruction had an excellent short-term prognosis; 2% died or had myocardial infarction compared with 18% of patients with critical obstruction.

A new look at Jinks-Hayman's method for the estimation of genetical components in diallel crosses.

A new interpretation of the assumption which states that genes are independently distributed across the parents leads to the construction of new estimates of the genetical components D, H1, H2 and F. Simulation experiments are used to compare the new estimates with the classical ones and with an improved (unbiased) version of those estimates. The new estimates show a better behaviour than their competitors in terms of bias and mean square deviation, especially for small diallels.

Varietal Response and Estimates of Heritability of Resistance to Meloidogyne javanica in Carrots.

With methods developed in this study, varietal responses to M. javanica were evaluated and heritability of resistance of two promising carrot cultivars was estimated. More egg masses were found on root systems inoculated with eggs added to the soil in three holes in 250 cm(3) cups than by mixing the inoculum with soil in the cups. A resistant breeding line, CNPH 1437, was discriminated from susceptible cultivar Nova Kuroda with inoculum levels higher than 2,000 eggs per cup. Greenhouse and field results suggested that cultivars Nantes Superior and Shin Kuroda were susceptible, Kuronan was somewhat tolerant, and Brasilia and Tropical were resistant to M. javanica. Nantes Superior or Shin Kuroda yielded less in carbofuran-treated soil (3 kg a.i./ha) than Kuronan, Brasilia, and Tropical did in nontreated soil. However, incorporation of the nematicide greatly increased yields of Kuronan (32%), Brasilia (62%), and Tropical (91%). Primary root galling at the seedling stage was an adequate parameter for resistance evaluation. Estimated heritability were 0.48 +/- 0.07 for primary root galling and 0.35 +/- 0.08 for egg mass production in Brasilia, and 0.16 +/- 0.11 for primary root galling and 0.31 +/- 0.09 for egg mass production in Kuronan.