Clinical and genetic factors involved in Porto-sinusoidal vascular disorder after oxaliplatin exposure.

BACKGROUND AND AIMS: Oxaliplatin (OX) has been described as a potential etiologic agent for porto-sinusoidal vascular disorder (PSVD). Our aim was to describe the natural history of PSVD due to OX in colon cancer (CRC) and identify risk factors for its development. METHODS: We made a multicenter retrospective case-control (ratio 1:3) study with patients diagnosed of PSVD-OX. Baseline data, end of treatment, years of follow-up and diagnosis of PSVD were collected and compared to controls (without PSVD). Besides, 16 different SNPs were selected from bibliography and analyzed by genotyping in the case group to identify potential genetic risk factors. RESULTS: 41 cases were identified, with a median time to PSVD diagnosis after the end of OX of 34 months. Spleen diameter was the strongest predictor of PSVD during treatment (OR 43.94 (14.48-133.336); p < 0.0001). Additionally, thrombocytopenia (<150 × 10^9) at one year was a significant disease risk marker (OR 9.35; 95% CI: 3.71-23.58; p = 0.001). We could not establish any significant association between the selected SNPs and PSVD diagnosis. CONCLUSION: The increase of spleen diameter is the strongest predictor of PSVD in patients treated with OX for CRC. These patients could be candidates for a specific follow-up of portal hypertension-related complications.

The Chilean socio-ethno-genomic cline.

Studies of the current Chilean population performed using classical genetic markers have established that the Chilean population originated primarily from the admixture of European people, particularly Spaniards, and Amerindians. A socioeconomic-ethno-genetic cline was established soon after the conquest. Spaniards born in Spain or Chile occupied the highest Socioeconomic Strata, while Amerindians belonged to the lowest. The intermediate strata consisted of people with different degrees of ethnic admixture; the larger the European admixture, the higher the Socioeconomic Level. The present study of molecular genomic markers sought to calculate the percentage of Amerindian admixture and revealed a finer distribution of this cline, as well as differences between two Amerindian groups: Aymara and Mapuche. The use of two socioeconomic classifications - Class and Socioeconomic Level - reveals important differences. Furthermore, Self-reported Ethnicity (self-assignment to an ethnic group) and Self-reported Ancestry (self-recognition of Amerindian ancestors) show variations and differing relationships between socioeconomic classifications and genomic Amerindian Admixture. These data constitute a valuable input for the formulation of public healthcare policy and show that the notions of Ethnicity, Socioeconomic Strata and Class should always be a consideration in policy development.

Tools for determining critical levels of atmospheric ammonia under the influence of multiple disturbances.

Critical levels (CLEs) of atmospheric ammonia based on biodiversity changes have been mostly calculated using small-scale single-source approaches, to avoid interference by other factors, which also influence biodiversity. Thus, it is questionable whether these CLEs are valid at larger spatial scales, in a multi- disturbances context. To test so, we sampled lichen diversity and ammonia at 80 sites across a region with a complex land-cover including industrial and urban areas. At a regional scale, confounding factors such as industrial pollutants prevailed, masking the CLEs. We propose and use a new tool to calculate CLEs by stratifying ammonia concentrations into classes, and focusing on the highest diversity values. Based on the significant correlations between ammonia and biodiversity, we found the CLE of ammonia for Mediterranean evergreen woodlands to be 0.69 µg m(-3), below the previously accepted value of 1.9 µg m(-3), and below the currently accepted pan-European CLE of 1.0 µg m(-3).

Surface plasmon resonance in doping analysis.

Doping analysis relies on the determination of prohibited substances that should not be present in the body of an athlete or that should be below a threshold value. In the case of xenobiotics their mere presence is sufficient to establish a doping offence. However, in the case of human biotics the analytical method faces the difficulty of distinguishing between endogenous and exogenous origin. For this purpose ingenious strategies have been implemented, often aided by state-of-the-art technological advancements such as mass spectrometry in all its possible forms. For larger molecules, i.e. protein hormones, the innate structural complexity, the heterogeneous nature, and the extremely low levels in biological fluids have rendered the analytical procedures heavily dependent of immunological approaches. Although approaches these confer specificity and sensitivity to the applications, most rely on the use of two, or even three, antibody incubations with the consequent increment in assay variability. Moreover, the requirement for different antibodies that separately recognise different epitopes in screening and confirmation assays further contributes to differences encountered in either measurement. The development of analytical techniques to measure interactions directly, such as atomic force microscopy, quartz crystal microbalance or surface plasmon resonance, have greatly contributed to the accurate evaluation of molecular interactions in all fields of biology, and expectations are that this will only increase. Here, an overview is provided of surface plasmon resonance, and its particular value in application to the field of doping analysis.

Purification of erythropoietin from human plasma samples using an immunoaffinity well plate.

A method is described to isolate human erythropoietin (hEPO) from plasma using an EPO-specific immunoaffinity micro well plate (IAP). The operating conditions of the method (binding, blocking and elution) were optimised to avoid isoform discrimination and cross-contamination with other glycoproteins. The overall hEPO recovery was ca. 56% and significant clean-up for plasmatic hEPO was achieved. Polyvinylpyrrolidone (PVP) was used as a blocking reagent and elution took place at pH 11.0. Under these conditions all isoforms from recombinant human EPOs (rhEPOs) and analogues were uniformly recovered guaranteeing lack of discrimination. The resulting procedure allowed isolating erythropoietin from plasma in conditions amenable to hEPO analysis by other techniques such as SDS-PAGE or IEF. Moreover, avoiding contamination with other glycosylated material allowed the identification in human plasma samples of the non-human N-glycolyl-neuraminic acid (Neu5Gc) using HPLC-FLD. Neu5Gc is present as 1-2% of the sialic acid content in rhEPO so this approach could be used to unequivocally detect abuse of rhEPOs or analogues as part of the doping control.

Decrease in viral load at weeks 12 and 24 in patients with chronic hepatitis B treated with lamivudine or adefovir predicts virological response at week 48.

AIM: The aim of our study was to evaluate the decrease in viral load (VL) that is able to predict antiviral treatment response at one year in patients with chronic hepatitis B. METHODS: The clinical records of 66 patients, 31 treated with lamivudine (LAM) and 35 treated with adefovir (ADF), were retrospectively reviewed. We measured viral DNA at months 1, 3 and 6. RESULTS: The LAM group showed virological response (VR) in 51.6% of patients. Baseline VL was higher in non responders (5.37 +/- 1.16 vs. 7.01 +/- 1.05; p < 0.001). Responders showed a higher percentage of VL decrease at month 3 from baseline (49.2 vs. 38.3%; p = 0.03). We designed a ROC curve and established a cutoff point for decrease of 30% that had 80% of negative predictive value (NPV).The ADF group showed VR in 57.1% of patients. Baseline VL was higher in nonresponders (4.67 +/- 1.22 vs. 5.78 +/- 1.34; p = 0.01). We observed a significant decrease in VL (log) at months 3 (2.6 +/- 1.1 vs. 1.3 +/- 1.3; p = 0.03) and 6 (2.6 +/- 1.2 vs. 1.3 +/- 1.2; p = 0.006). The percentage of decrease of VL from baseline was also statistically significant. We created ROC curves at months 3 and 6, and established the best cutoff points. At month 6 a decrease of 1 log in VL had a NPV of 80%, and a decrease of 20% in VL from baseline had 100% NPV. CONCLUSION: The decrease in viral DNA at weeks 12 and 24 can predict VR at one year in patients with chronic hepatitis B treated with LAM or ADF. This could optimize treatment.

Decrease in viral load at weeks 12 and 24 in patients with chronic hepatitis B treated with lamivudine or adefovir predicts virological response at week 48

Aim: the aim of our study was to evaluate the decrease in viralload (VL) that is able to predict antiviral treatment response at oneyear in patients with chronic hepatitis B.Methods: the clinical records of 66 patients, 31 treated withlamivudine (LAM) and 35 treated with adefovir (ADF), were retrospectivelyreviewed. We measured viral DNA at months 1, 3 and6.Results: the LAM group showed virological response (VR) in51.6% of patients. Baseline VL was higher in non responders(5.37 ± 1.16 vs. 7.01 ± 1.05; p < 0.001). Responders showed ahigher percentage of VL decrease at month 3 from baseline (49.2vs. 38.3%; p = 0.03). We designed a ROC curve and establisheda cutoff point for decrease of 30% that had 80% of negative predictivevalue (NPV).The ADF group showed VR in 57.1% of patients. Baseline VLwas higher in nonresponders (4.67 ± 1.22 vs. 5.78 ± 1.34; p =0.01). We observed a significant decrease in VL (log) at months 3(2.6 ± 1.1 vs. 1.3 ± 1.3; p = 0.03) and 6 (2.6 ± 1.2 vs. 1.3 ±1.2; p = 0.006). The percentage of decrease of VL from baselinewas also statistically significant. We created ROC curves atmonths 3 and 6, and established the best cutoff points. At month6 a decrease of 1 log in VL had a NPV of 80%, and a decrease of20% in VL from baseline had 100% NPV.Conclusion: the decrease in viral DNA at weeks 12 and 24can predict VR at one year in patients with chronic hepatitis Btreated with LAM or ADF. This could optimize treatment(AU)

Hamster zona pellucida is formed by four glycoproteins: ZP1, ZP2, ZP3, and ZP4.

The zona pellucida (ZP) is an extracellular glycoprotein matrix that surrounds all mammalian oocytes. Recent data have shown the presence of four glycoproteins (ZP1, ZP2, ZP3, and ZP4) in the ZP of human and rat rather than the three glycoproteins proposed in the mouse model. In the hamster (Mesocricetus auratus), it was previously described that ZP was composed of three different glycoproteins, called ZP1, ZP2, and ZP3, even though only ZP2 and ZP3 have been cloned thus far. The aim of the study was to determine whether hamster might also express four, rather than three, ZP proteins. The full-length cDNAs encoding hamster ZP glycoproteins 1 and 4 were isolated using rapid amplification cDNA ends (RACE). The cDNA of ZP1 contains an open reading frame of 1851 nucleotides encoding a polypeptide of 616 amino acid residues. The amino acid sequence of ZP1 revealed a high homology with other mammalian species like human (66%), rat (80%), and mouse (80%). The cDNA of ZP4 contains an open reading frame of 1632 nucleotides encoding a polypeptide of 543 amino acid residues. The deduced amino acid sequence of ZP4 revealed high overall homology with rat (82%) and human (78%). Subsequent mass spectrometric analysis of the hamster ZP allowed identification of peptides from all four glycoproteins. The data presented in this study provide evidence, for the first time, that the hamster ZP matrix is composed of four glycoproteins.

Can glycans unveil the origin of glycoprotein hormones? - human chorionic gonadotrophin as an example -.

Doping with (glyco)protein hormones represent an extremely challenging, analytical problem as nearly all are constitutively present at low concentrations that fluctuate according to circadian or alternative periodical, or external stimuli. Thus the mere concentration in a biological sample is only resolutive when this surpasses extreme values. As the vast majority of these molecules are produced by recombinant DNA technology it is believed that the exogenous molecules could bear the signature of the host cell. In particular, these could comprise structural differences originated from co or post-translational differences. In this study we have employed both proteomics and glycomics strategies to compare recombinant and urinary human chorionic gonadotrophin in order to evaluate this hypothesis. As anticipated the recombinant hormone could be shown to contain N-glycolyl neuraminic acid, a sialic acid that cannot be produced by humans. Furthermore, differences were observed in the overall glycosylation, in particular the presence of abundant hybrid-type glycans that were much less pronounced in the recombinant species. These differences were determined to occur predominantly in the alpha-subunit for which antidoping strategies focussed on these elements could be used for both chorionic gonadotrophin and lutrophin as they share the same alpha-subunit.

Mujer joven con dolor lumbar de larga duración / Young woman with long-course back pain

No disponible

Recombinant erythropoietin and analogues: a challenge for doping control.

Erythropoietin (EPO) increases the number of circulating erythrocytes and thus muscle oxygenation. The availability of the recombinant protein (rEPO) has increased the risk of its illegal use in sports, its detection being a difficult challenge. Five different hematopoietic parameters were initially chosen as indirect markers of rEPO abuse: concentration of serum EPO, concentration of serum-soluble transferrin receptors (sTFr), hematocrit, percentage of reticulocytes, and percentage of macrocytes. New models considering only hemoglobin, serum EPO concentration, and percentage of reticulocytes are simpler and seem to be more sensitive when low doses of rEPO are used. A more direct method of urine analysis (isoelectrofocusing, double blotting, and chemiluminescent detection) based on the charge differences between rEPO and endogenous EPO, related to their carbohydrate composition, provides proof of rEPO use. Furthermore, this approach permits the detection of darbepoetin, a direct analogue of EPO also known as NESP ("new erythropoiesis stimulating protein"). Recently a protein conjugate, "synthetic erythropoiesis protein" (SEP), containing precision-length, monodisperse, negatively charged polymers instead of oligosaccharides has been synthesized. Finally, EPO-mimetics are molecules capable of acting as EPO in dimerizing the EPO receptor. Two kinds of EPO-mimetics have been described: peptides and nonpeptides. The enhancement of oxygen availability to muscles by rEPO, analogues, and mimetics constitutes one of the main challenges to doping control. Major steps have already been developed for detection ofrEPO and some analogues. In the near future, the transfection to an athlete's body of genes that code for erythropoietin might be an emerging doping issue, and sports authorities have incorporated "gene doping" among the prohibited practices.

Genetic variants of serum butyrylcholinesterase in Chilean Mapuche Indians.

We estimated the frequencies of serum butyrylcholinesterase (BChE) alleles in three tribes of Mapuche Indians from southern Chile, using enzymatic methods, and we estimated the frequency of allele BCHE*K in one tribe using primer reduced restriction analysis (PCR-PIRA). The three tribes have different degrees of European admixture, which is reflected in the observed frequencies of the atypical allele BCHE*A: 1.11% in Huilliches, 0.89% in Cuncos, and 0% in Pehuenches. This result is evidence in favor of the hypothesis that BCHE*A is absent in native Amerindians. The frequencies of BCHE*F were higher than in most reported studies (3.89%, 5.78%, and 4.41%, respectively). These results are probably due to an overestimation of the frequency of allele BCHE*F, since none of the 20 BCHE UF individuals (by the enzymatic test) individuals analyzed showed either of the two DNA base substitutions associated with this allele. Although enzymatic methods rarely detect the presence of allele BCHE*K, PCR-PIRA found the allele in an appreciable frequency (5.76%), although lower than that found in other ethnic groups. Since observed frequencies of unusual alleles correspond to estimated percentages of European admixture, it is likely that none of these unusual alleles were present in Mapuche Indians before the arrival of Europeans.

Genetic marker variation in coastal populations of Chile.

Gene frequencies for nine genetic marker systems are presented for the following Chilean coastal populations: Paposo, Carelmapu, Laitec and Ukika. Historical and anthropological data suggest the presence of descendants of the Amerindian populations, specifically of Changos, Cuncos, Chonos and Yamanas in these populations. Results indicate that the studied groups maintain an important aboriginal genetic composition. According to Amerindian admixture estimates, the genetic isolation of coastal populations is lower than that of inland populations, suggesting that proximity to the sea facilitated gene flow. Genetic distances and dendrograms were obtained for these populations and another four Chilean Indian populations. Results agree with expectations, taking geographic isolation and non-aboriginal admixture into account.

Origin and evolutionary relationships of native Andean populations.

This paper represents an effort to explore the origin and the evolutionary relationships of native Andean populations using a multidisciplinary approach. Archeological and linguistic evidence is briefly reviewed. A genetic distance analysis among major linguistic groupings and among Andean and Amazonian native populations, together with information obtained from archaeological and linguistic sources was used to generate a migration model. It is suggested that in the late Pleistocene a group of nomadic hunters entered South America through the Isthmus of Panama and split afterwards into two groups, one moving southward into the central and south Andean areas and after crossing the Colombian, Equador and Peruvian highlands to people northwestern Argentina, the open park country of east Brazil and the Argentine Pampas. The second group migrated eastwards into Venezuela and Guyana and later southward, peopling the Brazilian Amazon. Following available waterways the Amazonian Indians expanded east and west arriving probably at the eastern slopes of the Andes some 3,500 years ago. It is hypothesized that present day Andean natives are descendants of the Amazonian groups that migrated eastwards.

[Genetic composition of Chilean population: rural communities of Elqui, Limari and Choapa valleys]. / Composición genética de la población chilena: las comunidades rurales de los valles de Elqui, Limarí y Choapa.

BACKGROUND: The population that inhabits the semiarid Northern zone of Chile arose from ethnic admixture between aborigines, Spanish conquerors and the influx, during the XVII century, of foreign aboriginal workers and a minority of African slaves. AIM: To study the phenotypic frequencies of 15 genetic markers among populations inhabiting valleys in the Northern zone of Chile and to estimate the percentage of indigenous, African and Caucasian admixture in these populations. MATERIAL AND METHODS: Throughout five different field works, blood samples were obtained from 120 individuals living in the Elqui valley, 120 individuals living in the Limari valley and 85 living in the Choapa valley. Blood groups, erythrocyte enzymes, plasma proteins and HLA markers were typified. RESULTS: In the populations studied, the contribution of non indigenous genes was low in relation with the time elapsed since the Spanish invasion. The Hardy-Weinberg disequilibrium for MNS system would have microevolutive implications. The admixture percentages in these valleys confirm ethnic and historic information. The variation of the enzyme esterase D is identical to that of other Chilean populations. CONCLUSIONS: The phenotypic and genetic frequencies in the three populations studied and different admixture of indigenous genes is inversely proportional to the geographic distance from Santiago, in Central Chile.

Mitochondrial DNA polymorphisms in Chilean aboriginal populations: implications for the peopling of the southern cone of the continent.

The mitochondrial DNAs (mtDNAs) from individuals belonging to three Chilean tribes, the Mapuche, the Pehuenche, and the Yaghan, were studied both by RFLP analysis and D-loop (control region) sequencing. RFLP analysis showed that 3 individuals (1.3%) belonged to haplogroup A, 19 (8%) to haplogroup B, 102 (43%) to haplogroup C, and 113 (47.7%) to haplogroup D. Among the 73 individuals analyzed by D-loop sequencing, we observed 37 different haplotypes defined by 52 polymorphic sites. Joint analysis of data obtained by RFLP and sequencing methods demonstrated that, regardless of the method of analysis, the mtDNA haplotypes of these three contemporary South American aborigine groups clustered into four main haplogroups, in a way similar to those previously described for other Amerindians. These results further revealed the absence of haplogroup A in both the Mapuche and Yaghan as well as the absence of haplogroup B in the Yaghan. These results suggest that the people of Tierra del Fuego are related to tribes from south-central South America.

[Genetics of addictive disorders]. / Genética de los desórdenes adictivos.

Given the spectacular advances of genetics during the last five years, it seems appropriate to revisit the important subject of genetics of alcoholism and substance abuse. In recent studies alcohol abuse was shown to have an hereditability of roughly 38%, whereas psychostimulant and opiate use exhibit hereditabilities of 11 to 45%. The hereditability of smoking was found to be around 50%. There is a strong comorbidity between alcoholism and smoking. More than 80% of alcoholics smoke cigarettes in the U.S.A. Other genetic methods such as linkage analysis, allele sharing methods, association studies and analysis of inbred, transgenic and gene-knockout rodents, have partially agreed in showing that the 5HT-1B serotonin receptor and the DRD1, DRD2 and DRD4 dopamine receptors, as well as the dopamine transporter DAT, play an important role in behaviors related to alcoholism and substance abuse. Some neurochemical markers, as for example monoamine oxidase and adenylate cyclase have also been implicated in addictive disorders. The aldehyde dehydrogenase allele ALDH2*2 has a protective effect against alcoholism. Two whole genome linkage studies have shown linkage to chromosomal regions that are in the proximity of the DRD4 dopamine receptor, the GABA receptor gene cluster and the alcohol dehydrogenase gene cluster.

[Coastal Chilean populations: genetic markers in four locations]. / Poblaciones costeras de Chile: marcadores genéticos en cuatro localidades.

BACKGROUND: Historical and anthropological data suggest the presence of descendents of Changos, Cuncos, Chonos and Yamanas, South American indian populations, in certain Chilean coastal villages. AIM: To assess the degree of South American indian admixture in Chilean coastal villages using protein markers, to complete the assessment of human biological diversity in Chile. SUBJECTS AND METHODS: ABO, Rh, MNS, Duffy and Kidd blood group systems were assessed in 47, 48, 55 and 24 individuals from Paposo, Carelmapu, Laitec and Ukika respectively. Phenotypic and gene frequencies were calculated. The degree of South American indian admixture was estimated from the ABO*O allele and Rh*dce haplotypes. RESULTS: High frequencies of ABO*O, Fy*a, Jk*b alleles, Dce and Ms haplotypes were found in all villages, consistent with the pattern expected for South American Aboriginal populations. The highest presence of South American indian admixture was present in Laitec with 80% and in Ukika with 74%. The figures for Paposo and Carelmapu were 60 and 65% respectively. CONCLUSIONS: According to South American indian admixture estimates, the genetic isolation of coastal populations is lower than that of inland subjects, suggesting that sea proximity facilitates gene flow.