Native American gene flow into Polynesia predating Easter Island settlement.

The possibility of voyaging contact between prehistoric Polynesian and Native American populations has long intrigued researchers. Proponents have pointed to the existence of New World crops, such as the sweet potato and bottle gourd, in the Polynesian archaeological record, but nowhere else outside the pre-Columbian Americas1-6, while critics have argued that these botanical dispersals need not have been human mediated7. The Norwegian explorer Thor Heyerdahl controversially suggested that prehistoric South American populations had an important role in the settlement of east Polynesia and particularly of Easter Island (Rapa Nui)2. Several limited molecular genetic studies have reached opposing conclusions, and the possibility continues to be as hotly contested today as it was when first suggested8-12. Here we analyse genome-wide variation in individuals from islands across Polynesia for signs of Native American admixture, analysing 807 individuals from 17 island populations and 15 Pacific coast Native American groups. We find conclusive evidence for prehistoric contact of Polynesian individuals with Native American individuals (around AD 1200) contemporaneous with the settlement of remote Oceania13-15. Our analyses suggest strongly that a single contact event occurred in eastern Polynesia, before the settlement of Rapa Nui, between Polynesian individuals and a Native American group most closely related to the indigenous inhabitants of present-day Colombia.

"Characterization of residential proximity to sources of environmental carcinogens in clusters of Acute Lymphoblastic Leukemia in San Luis Potosi, Mexico".

BACKGROUND: Acute Lymphoblastic Leukemia (ALL) is the most prevalent neoplasia in children and teenagers in Mexico. Although epidemiological data supports that children's residence close to emissions from vehicular traffic or industrial processes increases the risk of ALL; and the IARC states that benzene, PAHs, and PM 2.5 are well-known environmental carcinogens, there is a gap in linking these carcinogenic hazards with the sources and their distribution from scenario perspective. AIM: To identify ALL clusters in the population under 19 years of age and characterize the environment at the neighborhood level by integrating information on sources of carcinogenic exposure using spatial analysis techniques in the Metropolitan Area of San Luis Potosi, Mexico. METHODS: Using the Kernel Density test, we designed an ecological study to identify ALL clusters from incident cases in the population under 19 years of age. A multicriteria analysis was conducted to characterize the risk at the community level from carcinogenic sources. A hierarchical cluster analysis was performed to characterize risk at the individual level based on carcinogenic source count within 1 km for each ALL case. RESULTS: Eight clusters of carcinogenic sources were located within the five identified ALL clusters. The multicriteria analysis showed high-risk areas (by density of carcinogenic source) within ALL clusters. CONCLUSIONS: This study has a limited source and amount of available data on ALL cases, so selection bias is present as well as the inability to rule out residual confounding factors, since covariates were not included. However, in this study, children living in environments with high vehicular density, gas stations, brick kilns, incinerators, commercial establishments burning biomass, or near industrial zones may be at higher risk for ALL.

Association of Germline Variation in Driver Genes with Breast Cancer Risk in Chilean Population.

Cancer is a genomic disease, with driver mutations contributing to tumorigenesis. These potentially heritable variants influence risk and underlie familial breast cancer (BC). This study evaluated associations between BC risk and 13 SNPs in driver genes MAP3K1, SF3B1, SMAD4, ARID2, ATR, KMT2C, MAP3K13, NCOR1, and TBX3, in BRCA1/2-negative Chilean families. SNPs were genotyped using TaqMan Assay in 492 cases and 1285 controls. There were no associations between rs75704921:C>T (ARID2); rs2229032:A>C (ATR); rs3735156:C>G (KMT2C); rs2276738:G>C, rs2293906:C>T, rs4075943T:>A, rs13091808:C>T (MAP3K13); rs178831:G>A (NCOR1); or rs3759173:C>A (TBX3) and risk. The MAP3K1 rs832583 A allele (C/A+A/A) showed a protective effect in families with moderate BC history (OR = 0.7 [95% CI 0.5-0.9] p = 0.01). SF3B1 rs16865677-T (G/T+T/T) increased risk in sporadic early-onset BC (OR = 1.4 [95% CI 1.0-2.0] p = 0.01). SMAD4 rs3819122-C (A/C+C/C) increased risk in cases with moderate family history (OR = 2.0 [95% CI 1.3-2.9] p ≤ 0.0001) and sporadic cases diagnosed ≤50 years (OR = 1.6 [95% CI 1.1-2.2] p = 0.006). SMAD4 rs12456284:A>G increased BC risk in G-allele carriers (A/G + G/G) in cases with ≥2 BC/OC cases and early-onset cases (OR = 1.2 [95% CI 1.0-1.6] p = 0.04 and OR = 1.4 [95% CI 1.0-1.9] p = 0.03, respectively). Our study suggests that specific germline variants in driver genes MAP3K1, SF3B1, and SMAD4 contribute to BC risk in Chilean population.

Development of a small panel of SNPs to infer ancestry in Chileans that distinguishes Aymara and Mapuche components.

BACKGROUND: Current South American populations trace their origins mainly to three continental ancestries, i.e. European, Amerindian and African. Individual variation in relative proportions of each of these ancestries may be confounded with socio-economic factors due to population stratification. Therefore, ancestry is a potential confounder variable that should be considered in epidemiologic studies and in public health plans. However, there are few studies that have assessed the ancestry of the current admixed Chilean population. This is partly due to the high cost of genome-scale technologies commonly used to estimate ancestry. In this study we have designed a small panel of SNPs to accurately assess ancestry in the largest sampling to date of the Chilean mestizo population (n = 3349) from eight cities. Our panel is also able to distinguish between the two main Amerindian components of Chileans: Aymara from the north and Mapuche from the south. RESULTS: A panel of 150 ancestry-informative markers (AIMs) of SNP type was selected to maximize ancestry informativeness and genome coverage. Of these, 147 were successfully genotyped by KASPar assays in 2843 samples, with an average missing rate of 0.012, and a 0.95 concordance with microarray data. The ancestries estimated with the panel of AIMs had relative high correlations (0.88 for European, 0.91 for Amerindian, 0.70 for Aymara, and 0.68 for Mapuche components) with those obtained with AXIOM LAT1 array. The country's average ancestry was 0.53 ± 0.14 European, 0.04 ± 0.04 African, and 0.42 ± 0.14 Amerindian, disaggregated into 0.18 ± 0.15 Aymara and 0.25 ± 0.13 Mapuche. However, Mapuche ancestry was highest in the south (40.03%) and Aymara in the north (35.61%) as expected from the historical location of these ethnic groups. We make our results available through an online app and demonstrate how it can be used to adjust for ancestry when testing association between incidence of a disease and nongenetic risk factors. CONCLUSIONS: We have conducted the most extensive sampling, across many different cities, of current Chilean population. Ancestry varied significantly by latitude and human development. The panel of AIMs is available to the community for estimating ancestry at low cost in Chileans and other populations with similar ancestry.

In Vitro Effectiveness of a Terpenic Denture Cleanser on Old Biofilm Surfaces.

PURPOSE: To assess the effects of terpenic denture cleanser on denture biofilm removal using scanning electron microscopy (SEM). MATERIALS AND METHODS: The internal surface biofilm of four maxillary dentures was elucidated with Caristop-revelador Dual Tone, and 40 blue-stained specimens (0.6 cm × 0.4 cm × 2 mm) were obtained. These specimens were randomly assigned to one of the following four groups of 10 specimens each: control, Eci Clean, Fitty Dent, and terpenic denture cleanser. The period of immersion in each solution was 12 hours. Biofilm removal was evaluated using SEM, and morphologically varying areas of the SEM images were quantified with Imaris software. The data were analyzed using Kolmogorov-Smirnov, t-tests, ANOVA, and Tamhane's tests (p = 0.05). RESULTS: Data revealed that terpenic denture cleanser removed significantly more biofilm than any other treatment examined in this study. The t-tests revealed significant differences in the clean area that resulted from the use of the terpenic cleanser compared with the clean area that resulted from the use of Eci Clean (p = 0.013). Fitty Dent was the least effective and left dirty acrylic resin. The average areas with few removed layers were 59.3%, 43.3%, and 9.5% in Fitty Dent, Eci Clean, and terpenic cleanser groups, respectively. Tamhane's tests indicated that the Eci Clean and Fitty Dent groups were significantly different from the 0.5% terpenic cleanser group (p = 0.008). CONCLUSION: The terpenic denture cleanser was effective in removing denture biofilm.

Genetic Variants of Cytochrome CYP2D6 in Two Mixed Chilean Populations.

OBJECTIVES: It is known that the interindividual and interethnic variability of the genetic polymorphisms of CYP2D6 plays an important role in the presentation of adverse drug reactions and concerning lack of therapeutic effects in humans. However, there are few data available from mixed populations of Latin America, including the Chilean. The aim of this study was therefore to estimate the frequencies of CYP2D6 variants in two samples of hospitals from the northern (Hospital San José, HSJ) and eastern (Clínica Las Condes, CLC) parts of Santiago, Chile, with different degrees of Amerindian admixture (HSJ: 34.5%; CLC: 15.9%). METHODS: We used polymerase chain reaction followed by restriction endonuclease digestion (PCR-RFLP) to genotype 7 CYP2D6 alleles in 250 healthy unrelated individuals of Chilean Mestizo background. The detection of allele CYP2D6*5 and the duplication of this gene was performed by long-PCR. RESULTS: The degrees of Amerindian admixture are reflected in the observed frequencies of the CYP2D6*1 (HSJ: 58.26%; CLC: 41.06%), CYP2D6*2 (HSJ: 28.10%; CLC: 40.65%), and CYP2D6*4 (HSJ: 8.26%; CLC: 12.60%) alleles; the frequencies of CYP2D6*1 (p = 0.0002) and CYP2D6*2 (p = 0.0036) are significantly different between the samples. Four individuals (CLC: 0.41%; HSJ: 1.24%) could not be assigned to a genotype. We identified 3.25% of the genotypes which predict a poor metabolizer phenotype in CLC and 1.65% in HSJ. CONCLUSION: Our data indicate ethnic group-dependent genetic differences in the vulnerability to treatment with the large variety of drugs metabolized by the enzyme CYP2D6.

[Factors associated with success of a smoking cessation program]. / Factores asociados con el éxito de la terapia antitabaco en pacientes tratados con vareniclina: 10 años de experiencia en un programa multidisciplinario.

BACKGROUND: Smoking cessation therapies include counseling, psychological management and pharmacological therapy. Varenicline is the most effective and safe medication available. AIM: To study risk factors for the failure of pharmacological smoking cessation therapy with varenicline. PATIENTS AND METHODS: Retrospective analysis of 281 patients aged 45 ± 11 years (65% males) with a mean consumption of 31 ± 22 packs/year. They completed a smoking cessation program comprising psychological support and use of varenicline in a private clinic. Patients were followed with telephonic interviews during one year. A complete abstinence during one year was considered as a success of the program. RESULTS: The success rate of the program was 53.4%. The factors associated with failure were a high tobacco dependence rate determined with the Fageström test (Odds ratio (OR) 2.47, 95% confidence intervals (CI) 1.16-5.26, p = 0.02). An instruction level of more than 12 years was associated with a lower failure rate (OR 0.38 95% CI 0.18-0.82). CONCLUSIONS: A high tobacco dependence rate and a lower education were associated with a higher failure rate of this smoking cessation program.

Preliminary human health risk assessment of arsenic and fluoride in tap water from Zacatecas, México.

Zacatecas state is located in the central area of Mexico, where the underground water contains elevated quantities of natural arsenic and fluoride. In order to estimate health risk associated with human exposure to these pollutants, tap water samples from the southern-central region of the state were analyzed. Ninety percent of the samples exceeded the levels of arsenic established by the World Health Organization (WHO) of 0.01 mg/L and 43 % exceeded the limit established by the NOM-127-SSA1(1) of 0.025 mg/L. Forty-three percent of the samples had fluoride levels above the Mexican regulation limit of 1.5 mg/L (NOM-127-SSA1). We used WHO and EPA's health risk assessment method, we estimated 80 % of the inhabitants of sites studied could be exposed to arsenic levels higher than those recommended by EPA and the WHO, 22 % could be exposed to fluoride levels higher than those recommended by EPA, and 16 % of the local population may be in risk of suffering dental fluorosis.

Prevalence of the 35delG mutation in the GJB2 gene in two samples of non-syndromic deaf subjects from Chile.

Hearing loss is the most common inherited sensorial deficiency in humans; about 1 in 1000 children suffer from severe or profound hearing loss at birth. Mutations in the GJB2 gene are the most common cause of prelingual, non-syndromic autosomal recessive deafness in many populations; the c.35delG mutation is the most common in Caucasian populations. The frequency of the c.35delG mutation was estimated in two samples of deaf patients from Santiago, Chile. Unrelated non-syndromic sensorioneural deaf patients were examined: Group 1 consisted of 47 unrelated individuals with neurosensory deafness referred to the Chilean Cochlear Implant Program; Group 2 included 66 school children with prelingual deafness attending special education institutions for deaf people. Individuals with profound to moderate isolated neurosensory hearing loss with unknown etiology were included. The presence of the c.35delG mutation was evaluated by the allele-specific polymerase chain reaction method (PCR), and in some cases it was confirmed by direct DNA sequencing of the coding region of the GJB2 gene. Deaf relatives were present in 20.3% of the cases. We found 19.5% (22/113) patients with the c.35delG mutation, 6 of them homozygous; these rates are similar to frequencies found in other Latin American countries.

[Results of a multidisciplinary program to quit smoking]. / Resultados de un programa multidisciplinario para el control del hábito tabáquico.

BACKGROUND: Therapies to quit smoking are based on counseling, psychological therapy (PT), nicotine replacement therapy, bupropion or varenidine. AIM: To report the results of a multidisciplinary program to quit smoking. MATERIAL AND METHODS: Patients aged l8 years or more, motivated to quit smoking were admitted in a program based in counseling and PT, with or without pharmacological therapy. They were assessed by telephone during one year of follow up. Patients with unstable psychiatric diseases were excluded. Results were considered as "successful" when patients maintained abstinence during the year of follow up. A logistic regression analysis was done to identify factors associated with treatment success. RESULTS: Between 2005 and 2011, 198 patients aged 45 ± 11 years (56% males), who smoked 31.5 ± 20.6 packages/year, were treated. Of these, 155 (78%) were treated with varenidine, 26 (13%) with bupropion and 17 (9%>) did not receive pharmacological therapy. One hundred sixty eight patients completed the year of follow up. In 82 (49%>), treatment was successful and was negatively associated with a history of depression (odds ratio = 4 (95% confidence intervals 1.23-38.33). The main side effeets associated to varenidine and bupropion were nausea in 37 and 23%o, sleep disorders in 20 and 19%o and headache in 12 and 0%>, respectively. CONCLUSIONS: A multidisciplinary program to quit smoking achieved a 49%> of abstinence during a year of follow up.

Distal Symmetric Polyneuropathy Identification in Type 2 Diabetes Subjects: A Random Forest Approach.

The prevalence of diabetes mellitus is increasing worldwide, causing health and economic implications. One of the principal microvascular complications of type 2 diabetes is Distal Symmetric Polyneuropathy (DSPN), affecting 42.6% of the population in Mexico. Therefore, the purpose of this study was to find out the predictors of this complication. The dataset contained a total number of 140 subjects, including clinical and paraclinical features. A multivariate analysis was constructed using Boruta as a feature selection method and Random Forest as a classification algorithm applying the strategy of K-Folds Cross Validation and Leave One Out Cross Validation. Then, the models were evaluated through a statistical analysis based on sensitivity, specificity, area under the curve (AUC) and receiving operating characteristic (ROC) curve. The results present significant values obtained by the model with this approach, presenting 67% of AUC with only three features as predictors. It is possible to conclude that this proposed methodology can classify patients with DSPN, obtaining a preliminary computer-aided diagnosis tool for the clinical area in helping to identify the diagnosis of DSPN.

Risk-Profile and Feature Selection Comparison in Diabetic Retinopathy.

One of the main microvascular complications presented in the Mexican population is diabetic retinopathy which affects 27.50% of individuals with type 2 diabetes. Therefore, the purpose of this study is to construct a predictive model to find out the risk factors of this complication. The dataset contained a total of 298 subjects, including clinical and paraclinical features. An analysis was constructed using machine learning techniques including Boruta as a feature selection method, and random forest as classification algorithm. The model was evaluated through a statistical test based on sensitivity, specificity, area under the curve (AUC), and receiving operating characteristic (ROC) curve. The results present significant values obtained by the model obtaining 69% of AUC. Moreover, a risk evaluation was incorporated to evaluate the impact of the predictors. The proposed method identifies creatinine, lipid treatment, glomerular filtration rate, waist hip ratio, total cholesterol, and high density lipoprotein as risk factors in Mexican subjects. The odds ratio increases by 3.5916 times for control patients which have high levels of cholesterol. It is possible to conclude that this proposed methodology is a preliminary computer-aided diagnosis tool for clinical decision-helping to identify the diagnosis of DR.

Persistence of COVID-19 Symptoms after Recovery in Mexican Population.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease (COVID-19), a highly contagious infectious disease that has caused many deaths worldwide. Despite global efforts, it continues to cause great losses, and leaving multiple unknowns that we must resolve in order to face the pandemic more effectively. One of the questions that has arisen recently is what happens, after recovering from COVID-19. For this reason, the objective of this study is to identify the risk of presenting persistent symptoms in recovered from COVID-19. This case-control study was conducted in one state of Mexico. Initially the data were obtained from the participants, through a questionnaire about symptoms that they had at the moment of the interview. Initially were captured the collected data, to make a dataset. After the pre-processed using the R project tool to eliminate outliers or missing data. Obtained finally a total of 219 participants, 141 recovered and 78 controls. It was used confidence level of 90% and a margin of error of 7%. From results it was obtained that all symptoms have an associated risk in those recovered. The relative risk of the selected symptoms in the recovered patients goes from 3 to 22 times, being infinite for the case of dyspnea, due to the fact that there is no control that presents this symptom at the moment of the interview, followed by the nausea and the anosmia with a RR of 8.5. Therefore, public health strategies must be rethought, to treat or rehabilitate, avoiding chronic problems in patients recovered from COVID-19.

Probability of exclusion in paternity testing: time to reassess.

The average exclusion probability is a measure of efficiency in paternity testing; it refers to the a priori ability of a battery of tests to detect paternity inconsistencies. This parameter measures the capacity of the system to detect a false accusation of paternity. Traditionally, this average exclusion probability has been estimated as the probability of excluding a man who is not the father by an inconsistency in at least one of the studied loci. We suggest that this criterion should be corrected, as currently the presumed father is excluded when at least three genetic inconsistencies are found with the child being tested, not just one. This change of criterion has occurred because of the use of microsatellite loci, whose mutation rates are much greater than those of the coding genes used previously in paternity studies. We propose the use of the average probability of exclusion for at least three loci (not only one), as an honest measure of the combined probability of exclusion of several loci, and we propose an algebraic expression to calculate it.

Development of a small panel of SNPs to infer ancestry in Chileans that distinguishes Aymara and Mapuche components

BACKGROUND: Current South American populations trace their origins mainly to three continental ancestries, i.e. European, Amerindian and African. Individual variation in relative proportions of each of these ancestries may be confounded with socio-economic factors due to population stratification. Therefore, ancestry is a potential confounder variable that should be considered in epidemiologic studies and in public health plans. However, there are few studies that have assessed the ancestry of the current admixed Chilean population. This is partly due to the high cost of genome-scale technologies commonly used to estimate ancestry. In this study we have designed a small panel of SNPs to accurately assess ancestry in the largest sampling to date of the Chilean mestizo population (n = 3349) from eight cities. Our panel is also able to distinguish between the two main Amerindian components of Chileans: Aymara from the north and Mapuche from the south. RESULTS: A panel of 150 ancestry-informative markers (AIMs) of SNP type was selected to maximize ancestry informativeness and genome coverage. Of these, 147 were successfully genotyped by KASPar assays in 2843 samples, with an average missing rate of 0.012, and a 0.95 concordance with microarray data. The ancestries estimated with the panel of AIMs had relative high correlations (0.88 for European, 0.91 for Amerindian, 0.70 for Aymara, and 0.68 for Mapuche components) with those obtained with AXIOM LAT1 array. The country's average ancestry was 0.53 ± 0.14 European, 0.04 ± 0.04 African, and 0.42 ± 0.14 Amerindian, disaggregated into 0.18 ± 0.15 Aymara and 0.25 ± 0.13 Mapuche. However, Mapuche ancestry was highest in the south (40.03%) and Aymara in the north (35.61%) as expected from the historical location of these ethnic groups. We make our results available through an online app and demonstrate how it can be used to adjust for ancestry when testing association between incidence of a disease and nongenetic risk factors. CONCLUSIONS: We have conducted the most extensive sampling, across many different cities, of current Chilean population. Ancestry varied significantly by latitude and human development. The panel of AIMs is available to the community for estimating ancestry at low cost in Chileans and other populations with similar ancestry.

Muir-Torre syndrome: case report and molecular characterization.

CONTEXT: Muir-Torre syndrome is a rare autosomal dominant genodermatosis caused by mutations in the mismatch repair genes. It is characterized by the presence of sebaceous skin tumors and internal malignancies, affecting mainly the colon, rectum and urogenital tract. Awareness of this syndrome among physicians can lead to early diagnosis of these malignancies and a better prognosis. CASE REPORT: We report the case of a Chilean patient who, over the course of several years, had multiple skin lesions, endometrial cancer and colon cancer. The syndrome was diagnosed using molecular techniques such as microsatellite instability analysis, immunohistochemistry and DNA sequencing, which allowed us to find the causative mutation. CONCLUSION: Molecular diagnostics is a highly useful tool, since it allows clinicians to confirm the presence of mutations causing Muir-Torre syndrome. It is complementary to the analysis of the clinical data, such as dermatological presentation, presence of visceral malignancies and family history of colorectal tumors, and it provides important knowledge to help physicians and patients choose between treatment options.

Doppler ultrasound evaluation in preeclampsia.

BACKGROUND: Worldwide preeclampsia (PE) is the leading cause of maternal death and affects 5 to 8% of pregnant women. PE is characterized by elevated blood pressure and proteinuria. Doppler Ultrasound (US) evaluation has been considered a useful method for prediction of PE; however, there is no complete data about the most frequently altered US parameters in the pathology. The aim of this study was to evaluate the uterine, umbilical, and the middle cerebral arteries using Doppler US parameters [resistance index (RI), pulsatility index (PI), notch (N), systolic peak (SP) and their combinations] in pregnant women, in order to make a global evaluation of hemodynamic repercussion caused by the established PE. RESULTS: A total of 102 pregnant Mexican women (65 PE women and 37 normotensive women) were recruited in a cases and controls study. Blood velocity waveforms from uterine, umbilical, and middle cerebral arteries, in pregnancies from 24 to 37 weeks of gestation were recorded by trans-abdominal examination with a Toshiba Ultrasound Power Vision 6000 SSA-370A, with a 3.5 MHz convex transducer. Abnormal general Doppler US profile showed a positive association with PE [odds ratio (OR) = 2.93, 95% confidence interval (CI) = 1.2 - 7.3, P = 0.021)], and a specificity and predictive positive value of 89.2% and 88.6%, respectively. Other parameters like N presence, RI and PI of umbilical artery, as well as the PI of middle cerebral artery, showed differences between groups (P values < 0.05). CONCLUSION: General Doppler US result, as well as N from uterine vessel, RI from umbilical artery, and PI from umbilical and middle cerebral arteries in their individual form, may be considered as tools to determine hemodynamic repercussion caused by PE.

Aneurismal subarachnoid hemorrhage in a Chilean population, with emphasis on risk factors.

BACKGROUND: Subarachnoid Hemorrhage (SAH) is caused principally by the rupture of intracranial aneurisms. Important risk factors have been described such as age, sex, hypertension (HT) and season of the year, among others. The objective is to investigate the demographic characteristics and possible risk factors in a population of Chilean patients. METHODS: This retrospective study was based on the analysis of 244 clinical records of patients diagnosed with aneurismal SAH who were discharged from the Instituto de Neurocirugía ASENJO in Santiago, Chile. RESULTS: The mean age of patients was 49.85 years and the male:female ratio was 1:2.7. The signs and symptoms were not different between sexes; cephalea (85.7%) was predominant, followed by loss of consciousness, vomiting/nausea and meningeal signs. Risk factors included sex, age and HT. Concordant with other reports, the incidence of SAH was greatest in spring. CONCLUSIONS: The demographic characteristics and risk factors observed in patients with aneurismal SAH treated in ASENJO were comparable to those of other populations. We were not able to conclude that tobacco and alcohol consumption were risk factors for this population.

DNA extraction from formalin-fixed laryngeal biopsies: Comparison of techniques.

CONCLUSION: PCR-quality DNA could be extracted from formalin-fixed paraffin-embedded (FFPE) samples with amplicons of at least 390 bp. Paraffin removal was not a necessary step. Proteinase K digestion was as efficient as the commercial kit for DNA extraction with a lower cost. OBJECTIVES: To compare different DNA extraction protocols for FFPE samples and to describe the suitability of the extracted DNA for PCR reactions. METHODS: For deparaffinization the following techniques were compared: alkaline heat, xylene, and no removal. For DNA extraction, proteinase K digestion and organic extraction were compared. A commercial extraction kit was included as standard. DNA quality was assessed by PCR amplification of the HFE gene, for amplicons of 208 and 390 bp. RESULTS: Extraction with the commercial kit and proteinase K digestion were more efficient than other techniques, with no statistical difference between them for both amplicons. The proteinase K digestion buffer had a cost of U$ 0.2 per sample and the commercial kit of U$7 per sample.

Factores asociados con el éxito de la terapia antitabaco en pacientes tratados con vareniclina: 10 años de experiencia en un programa multidisciplinario / Factors associated with success of a smoking cessation program

Background: Smoking cessation therapies include counseling, psychological management and pharmacological therapy. Varenicline is the most effective and safe medication available. Aim: To study risk factors for the failure of pharmacological smoking cessation therapy with varenicline. Patients and Methods: Retrospective analysis of 281 patients aged 45 ± 11 years (65% males) with a mean consumption of 31 ± 22 packs/year. They completed a smoking cessation program comprising psychological support and use of varenicline in a private clinic. Patients were followed with telephonic interviews during one year. A complete abstinence during one year was considered as a success of the program. Results: The success rate of the program was 53.4%. The factors associated with failure were a high tobacco dependence rate determined with the Fageström test (Odds ratio (OR) 2.47, 95% confidence intervals (CI) 1.16-5.26, p = 0.02). An instruction level of more than 12 years was associated with a lower failure rate (OR 0.38 95% CI 0.18-0.82). Conclusions: A high tobacco dependence rate and a lower education were associated with a higher failure rate of this smoking cessation program.