Germline mutations of breast cancer susceptibility genes through expanded genetic analysis in unselected Colombian patients.

BACKGROUND: In Colombia and worldwide, breast cancer (BC) is the most frequently diagnosed neoplasia and the leading cause of death from cancer among women. Studies predominantly involve hereditary and familial cases, demonstrating a gap in the literature regarding the identification of germline mutations in unselected patients from Latin-America. Identification of pathogenic/likely pathogenic (P/LP) variants is important for shaping national genetic analysis policies, genetic counseling, and early detection strategies. The present study included 400 women with unselected breast cancer (BC), in whom we analyzed ten genes, using Whole Exome Sequencing (WES), know to confer risk for BC, with the aim of determining the genomic profile of previously unreported P/LP variants in the affected population. Additionally, Multiplex Ligation-dependent Probe Amplification (MLPA) was performed to identify Large Genomic Rearrangements (LGRs) in the BRCA1/2 genes. To ascertain the functional impact of a recurrent intronic variant (ATM c.5496 + 2_5496 + 5delTAAG), a minigene assay was conducted. RESULTS: We ascertained the frequency of P/LP germline variants in BRCA2 (2.5%), ATM (1.25%), BRCA1 (0.75%), PALB2 (0.50%), CHEK2 (0.50%), BARD1 (0.25%), and RAD51D (0.25%) genes in the population of study. P/LP variants account for 6% of the total population analyzed. No LGRs were detected in our study. We identified 1.75% of recurrent variants in BRCA2 and ATM genes. One of them corresponds to the ATM c.5496 + 2_5496 + 5delTAAG. Functional validation of this variant demonstrated a splicing alteration probably modifying the Pincer domain and subsequent protein structure. CONCLUSION: This study described for the first time the genomic profile of ten risk genes in Colombian women with unselected BC. Our findings underscore the significance of population-based research, advocating the consideration of molecular testing in all women with cancer.

Functional Analysis of BRCA1 3'UTR Variants Predisposing to Breast Cancer.

Purpose: Breast Cancer (BC) is the main female cancer diagnosed worldwide, and it has been described that few genes, such as BRCA1, have a high penetrance for this type of cancer. In this manuscript, we were interested in evaluating the effect of 3'UTR variants on BRCA1 expression. Patients and Methods: To accomplish this objective, Whole Exome Sequencing (WES) data of 400 patients with unselected BC was used to filter variants located in the region of interest of BRCA1 gene, finding two of them (c.*36C>G and c.*369_373del). miRGate and miRanda in silico tools were used to predict microRNA (miRNA) interaction. Results: The two variants (c.*36C>G, c.*369_373del) were predicted to affect miRNA interaction. After cloning of BRCA1 3'UTR into pMIR-Report vector, the construct was transfected into two BC cell lines (MDA-MB-231 and MCF-7), and the variant c.*36C>G evidenced overexpression of reporter gene luciferase, showing that the transcript was not being degraded by the miRNA in MDA-MB-231 cells. Conclusion: The variant seems to protect against Triple Negative BC probably due to the expression level of miRNA in this particular cell line (MDA-MB-231). This is consistent with the clinical history of the patients who harbor BC Hormone Receptors positive (HR+).

Performance Comparison of a Duplex Implementation of the CDC EUA 2019-nCoV Assay with the Seegene Allplex-SARS-CoV-2 Assay for the Detection of SARS-CoV-2 in Nasopharyngeal Swab Samples.

RT-PCR tests have become the gold standard for detecting the SARS-CoV-2 virus in the context of the COVID-19 pandemic. Because of the extreme number of cases in periodic waves of infection, there is a severe financial and logistical strain on diagnostic laboratories. For this reason, alternative implementations and validations of academic protocols that employ the lowest cost and the most widely available equipment and reagents found in different regions are essential. In this study, we report an alternative implementation of the EUA 2019-nCoV CDC assay which uses a previously characterized duplex PCR reaction for the N1 and RNAse P target regions and an additional uniplex reaction for the N2 target region. Taking advantage of the Abbott m2000 Sample Preparation System and NEB Luna Universal Probe One-Step RT-qPCR kit, some of the most widely available and inexpensive nucleic acid extraction and amplification platforms, this modified test shows state-of-the-art analytical and clinical sensitivities and specificities when compared with the Seegene Allplex-SARS-CoV-2 assay. This implementation has the potential to be verified and implemented by diagnostic laboratories around the world to guarantee low-cost RT-PCR tests that can take advantage of widely available equipment and reagents.

Entropy-Based Diversification Approach for Bio-Computing Methods.

Nature-inspired computing is a promising field of artificial intelligence. This area is mainly devoted to designing computational models based on natural phenomena to address complex problems. Nature provides a rich source of inspiration for designing smart procedures capable of becoming powerful algorithms. Many of these procedures have been successfully developed to treat optimization problems, with impressive results. Nonetheless, for these algorithms to reach their maximum performance, a proper balance between the intensification and the diversification phases is required. The intensification generates a local solution around the best solution by exploiting a promising region. Diversification is responsible for finding new solutions when the main procedure is trapped in a local region. This procedure is usually carryout by non-deterministic fundamentals that do not necessarily provide the expected results. Here, we encounter the stagnation problem, which describes a scenario where the search for the optimum solution stalls before discovering a globally optimal solution. In this work, we propose an efficient technique for detecting and leaving local optimum regions based on Shannon entropy. This component can measure the uncertainty level of the observations taken from random variables. We employ this principle on three well-known population-based bio-inspired optimization algorithms: particle swarm optimization, bat optimization, and black hole algorithm. The proposal's performance is evidenced by solving twenty of the most challenging instances of the multidimensional knapsack problem. Computational results show that the proposed exploration approach is a legitimate alternative to manage the diversification of solutions since the improved techniques can generate a better distribution of the optimal values found. The best results are with the bat method, where in all instances, the enhanced solver with the Shannon exploration strategy works better than its native version. For the other two bio-inspired algorithms, the proposal operates significantly better in over 70% of instances.

Relationship between the concentration of anti-Müllerian hormone and antral follicle count in pasture-managed Holstein cows in the high tropics.

We evaluated the relationship between plasma levels of anti-Müllerian hormone (AMH) and the number of antral follicles at the restart of the follicular wave in crossbred Holstein cows reared under extensive grazing systems over 2500 m above sea level. The study included 140 cows from 15 farms that were in average at the 75.3 ± 2.10 d post partum. Animals were synchronized according to the following regime: day 0 = intravaginal progesterone releasing device (IPD) + estradiol benzoate (EB); day 7: withdrawal of IPD + prostaglandin; and day 8: EB, for restart of the follicular wave on day 11. On this day 11, antral follicle counts (AFCs) were made by transrectal ultrasound, and a plasma sample was taken for the determination of AMH. The mean AMH plasma level was 0.06 ± 0.03 ng/ml and the mean AFC was 17.26 ± 0.38 follicles. A strong positive linear correlation was found between these two variables (r = 0.783, r = 0.613, P < 0.0001). Cows were categorized according to AMH concentration as high (>0.09 ng/ml), intermediate (0.09-0.05 ng/ml) or low (<0.05 ng/ml). Cows with high AMH presented a higher AFC (25.0 ± 2.21 follicles) than those with low AMH (14.08 ± 2.68 follicles; P < 0.001. Our results suggest that the cut-off value of AMH = 0.09 ng/ml may be useful for selecting donors in multiple ovulation embryo transfer programs involving cows with these characteristics. Our data further suggest that AMH plasma concentration correlates with AFC and can be used as an endocrine biomarker of the number of antral follicles present at a given moment of the estrous cycle in crossbred Holstein cows raised at altitudes above 2500 m.

Structural Modelling of KCNQ1 and KCNH2 Double Mutant Proteins, Identified in Two Severe Long QT Syndrome Cases, Reveals New Insights into Cardiac Channelopathies.

Congenital long QT syndrome (LQTS) is a cardiac channelopathy characterized by a prolongation of the QT interval and T-wave abnormalities, caused, in most cases, by mutations in KCNQ1, KCNH2, and SCN5A. Although the predominant pattern of LQTS inheritance is autosomal dominant, compound heterozygous mutations in genes encoding potassium channels have been reported, often with early disease onset and more severe phenotypes. Since the molecular mechanisms underlying severe phenotypes in carriers of compound heterozygous mutations are unknown, it is possible that these compound mutations lead to synergistic or additive alterations to channel structure and function. In this study, all-atom molecular dynamic simulations of KCNQ1 and hERG channels were carried out, including wild-type and channels with compound mutations found in two patients with severe LQTS phenotypes and limited family history of the disease. Because channels can likely incorporate different subunit combinations from different alleles, there are multiple possible configurations of ion channels in LQTS patients. This analysis allowed us to establish the structural impact of different configurations of mutant channels in the activated/open state. Our data suggest that channels with these mutations show moderate changes in folding energy (in most cases of stabilizing character) and changes in channel mobility and volume, differentiating them from each other and from WT. This would indicate possible alterations in K+ ion flow. Hetero-tetrameric mutant channels showed intermediate structural and volume alterations vis-à-vis homo-tetrameric channels. These findings support the hypothesis that hetero-tetrameric channels in patients with compound heterozygous mutations do not necessarily lead to synergistic structural alterations.

NMR-based leaf metabolic profiling of V. planifolia and three endemic Vanilla species from the Peruvian Amazon.

The fruit of Vanilla planifolia is broadly preferred by the agroindustry and gourmet markets due to its refined flavor and aroma. Peruvian Vanilla has been proposed as a possible source for genetic improvement of existing Vanilla cultivars, but, little has been done to facilitate comprehensive studies of these and other Vanilla. Here, a nuclear magnetic resonance (NMR) metabolomic platform was developed to profile for the first time the leaves - organ known to accumulate vanillin putative precursors - of V. planifolia and those of Peruvian V. pompona, V. palmarum, and V. ribeiroi, with the aim to determine metabolic differences among them. Analysis of the NMR spectra allowed the identification of thirty-six metabolites, twenty-five of which were quantified. One-way ANOVA and post-hoc Tukey test revealed that these metabolites changed significantly among species, whilst multivariate-analyses allowed the identification of malic and homocitric acids, together with two vanillin precursors, as relevant metabolic markers for species differentiation.

A Novel Splice-Site Mutation in the ELN Gene Suggests an Alternative Mechanism for Vascular Elastinopathies.

The ELN gene encodes elastin, a fundamental protein of the extracellular matrix that confers elasticity to different tissues including blood vessels. The formation of elastin fibers is a complex process involving monomer coacervation and subsequent crosslinking. Mutations in exons 1-29 of the ELN gene have been linked to supravalvular aortic stenosis (SVAS) whereas mutations in exons 30-33 are associated with autosomal dominant cutis laxa (ADCL). This striking segregation has led to the hypothesis that distinct molecular mechanisms underlie both diseases. SVAS is believed to arise through haploinsufficiency while ADCL is hypothesized to be caused by a dominant negative effect. Here, we describe a patient with SVAS harboring a novel splice-site mutation in the last exon of ELN. The location of this mutation is not consistent with current knowledge of SVAS, since all mutations reported in the C-terminus have been found in ADCL patients, and a thorough evaluation did not reveal significant skin involvement in this case. RT-PCR analysis of skin tissue showed that C-terminal mutations in the region can lead to the production of aberrant transcripts through intron retention and activation of cryptic splice sites and suggest that disruption of the very last exon can lead to functional haploinsufficiency potentially related to SVAS.

Morphological and metabolic profiling of a tropical-adapted potato association panel subjected to water recovery treatment reveals new insights into plant vigor.

Potato (Solanum tuberosum L.) is one of the world's most important crops, but it is facing major challenges due to climatic changes. To investigate the effects of intermittent drought on the natural variability of plant morphology and tuber metabolism in a novel potato association panel comprising 258 varieties we performed an augmented block design field study under normal irrigation and under water-deficit and recovery conditions in Ica, Peru. All potato genotypes were profiled for 45 morphological traits and 42 central metabolites via nuclear magnetic resonance. Statistical tests and norm of reaction analysis revealed that the observed variations were trait specific, that is, genotypic versus environmental. Principal component analysis showed a separation of samples as a result of conditional changes. To explore the relational ties between morphological traits and metabolites, correlation-based network analysis was employed, constructing one network for normal irrigation and one network for water-recovery samples. Community detection and difference network analysis highlighted the differences between the two networks, revealing a significant correlational link between fumarate and plant vigor. A genome-wide association study was performed for each metabolic trait. Eleven single nucleotide polymorphism (SNP) markers were associated with fumarate. Gene Ontology analysis of quantitative trait loci regions associated with fumarate revealed an enrichment of genes regulating metabolic processes. Three of the 11 SNPs were located within genes, coding for a protein of unknown function, a RING domain protein and a zinc finger protein ZAT2. Our findings have important implications for future potato breeding regimes, especially in countries suffering from climate change.

Ultra-Clean Pure Shift 1H-NMR applied to metabolomics profiling.

Even though Pure Shift NMR methods have conveniently been used in the assessment of crowded spectra, they are not commonly applied to the analysis of metabolomics data. This paper exploits the recently published SAPPHIRE-PSYCHE methodology in the context of plant metabolome. We compare single pulse, PSYCHE, and SAPPHIRE-PSYCHE spectra obtained from aqueous extracts of Physalis peruviana fruits. STOCSY analysis with simplified SAPPHIRE-PSYCHE spectra of six types of Cape gooseberry was carried out and the results attained compared with classical STOCSY data. PLS coefficients analysis combined with 1D-STOCSY was performed in an effort to simplify biomarker identification. Several of the most compromised proton NMR signals associated with critical constituents of the plant mixture, such as amino acids, organic acids, and sugars, were more cleanly depicted and their inter and intra correlation better reveled by the Pure Shift methods. The simplified data allowed the identification of glutamic acid, a metabolite not observed in previous studies of Cape gooseberry due to heavy overlap of its NMR signals. Overall, the results attained indicated that Ultra-Clean Pure Shift spectra increase the performance of metabolomics data analysis such as STOCSY and multivariate coefficients analysis, and therefore represent a feasible and convenient additional tool available to metabolomics.

Perforator Propeller Flaps for the Coverage of Middle and Distal Leg Soft-tissue Defects.

BACKGROUND: Local propeller flaps preserve the main vascular arteries of the lower extremity and muscle function, avoiding the need for a microsurgical anastomosis and the benefit of providing a "like with like" coverage. Our goal in this study was to demonstrate the versatility, safety, and complications of the local propeller flaps for lower extremity reconstruction. METHODS: We present a series of 28 patients in whom we used local propeller flaps to restore small-to-medium soft-tissue defects of the lower limb in different hospitals of Managua, Nicaragua. RESULTS: Flap average dimensions were of 48 cm2. Flap rotation was performed in 180 degrees in 85% of the cases. The propeller flaps were based on a single perforator, from the posterior tibial artery in 50%, anterior tibial artery in 39.3%, and peroneal artery in 10.7% of the cases. Complications occurred in 14% of the propeller flaps performed, with 3 partial necrosis of less than 15% of the flap transposed. Complications of the patients occurred in both sex groups; however, for the female group, there was a 75% of complications with a tendency toward statistical significance of P = 0.038. Donor site of the flap was closed primarily in 85.7% (24) of the cases. CONCLUSIONS: In our opinion, the availability and safety of local propeller flaps, justifies its use in cases where microsurgical techniques are not an option for the reconstruction of the middle and distal extremity, in small-to-medium defects of soft-tissue coverage of the lower limb.

Identification of a New Candidate Locus for Ebstein Anomaly in 1p36.2.

Ebstein anomaly (EA) is a rare congenital heart defect (CHD) with a poorly characterized genetic etiology. However, some EA patients carry deletions in 1p36, all of which have been reported to carry distal deletions and share loss of the PRDM16 gene, which is currently considered the most likely candidate for EA development in this region. Here, we report a patient with an 11.96-Mb proximal 1p36 deletion, without loss of PRDM16, who presented with EA and a proximal deletion phenotype. This finding suggests that PRDM16 loss is not required for the development of EA in 1p36 deletions and that the loss of an additional proximal locus in 1p36 is also likely associated with EA. Our data suggest that a distal locus containing the SKI gene and a proximal locus containing the CHD-associated genes RERE and UBE4B are the most probable etiological factors for EA in patients with 1p36 deletion syndrome.

NMR-based metabolic study of fruits of Physalis peruviana L. grown in eight different Peruvian ecosystems.

The berry of Physalis peruviana L. (Solanaceae) represents an important socio-economical commodity for Latin America. The absence of a clear phenotype renders it difficult to trace its place of origin. In this study, Cape gooseberries from eight different regions within the Peruvian Andes were profiled for their metabolism implementing a NMR platform. Twenty-four compounds could be unequivocally identified and sixteen quantified. One-way ANOVA and post-hoc Tukey test revealed that all of the quantified metabolites changed significantly among regions: Bambamarca I showed the most accumulated significant differences. The coefficient of variation demonstrated high phenotypic plasticity for amino acids, while sugars displayed low phenotypic plasticity. Correlation analysis highlighted the closely coordinated behavior of the amino acid profile. Finally, PLS-DA revealed a clear separation among the regions based on their metabolic profiles, accentuating the discriminatory capacity of NMR in establishing significant phytochemical differences between producing regions of the fruit of P. peruviana L.

Identification of clinically relevant phenotypes in patients with Ebstein anomaly.

BACKGROUND: Ebstein anomaly (EA) is a heterogeneous congenital heart defect (CHD), frequently accompanied by diverse cardiac and extracardiac comorbidities, resulting in a wide range of clinical outcomes. HYPOTHESIS: Phenotypic characterization of EA patients has the potential to identify variables that influence prognosis and subgroups with distinct contributing factors. METHODS: A comprehensive cross-sectional phenotypic characterization of 147 EA patients from one of the main referral institutions for CHD in Colombia was carried out. The most prevalent comorbidities and distinct subgroups within the patient cohort were identified through cluster analysis. RESULTS: The most prevalent cardiac comorbidities identified were atrial septal defect (61%), Wolff-Parkinson-White syndrome (WPW; 27%), and right ventricular outflow tract obstruction (25%). Cluster analysis showed that patients can be classified into 2 distinct subgroups with defined phenotypes that determine disease severity and survival. Patients in cluster 1 represented a particularly homogeneous subgroup with a milder spectrum of disease, including only patients with WPW and/or supraventricular tachycardia (SVT). Cluster 2 included patients with more diverse cardiovascular comorbidities. CONCLUSIONS: This study represents one of the largest phenotypic characterizations of EA patients reported. The data show that EA is a heterogeneous disease, very frequently associated with cardiovascular and noncardiovascular comorbidities. Patients with WPW and SVT represent a homogeneous subgroup that presents with a less severe spectrum of disease and better survival when adequately managed. This should be considered when searching for genetic causes of EA and in the clinical setting.

Protocol to obtain targeted transcript sequence data from snake venom samples collected in the Colombian field.

Snake venoms are a mixture of different molecules that can be used in the design of drugs for various diseases. The study of these venoms has relied on strategies that use complete venom extracted from animals in captivity or from venom glands that require the sacrifice of the animals. Colombia, a country with political and geographical conflicts has difficult access to certain regions. A strategy that can prevent the sacrifice of animals and could allow the study of samples collected in the field is necessary. We report the use of lyophilized venom from Crotalus durissus cumanensis as a model to test, for the first time, a protocol for the amplification of complete toxins from Colombian venom samples collected in the field. In this protocol, primers were designed from conserved region from Crotalus sp. mRNA and EST regions to maximize the likelihood of coding sequence amplification. We obtained the sequences of Metalloproteinases II, Disintegrins, Disintegrin-Like, Phospholipases A2, C-type Lectins and Serine proteinases from Crotalus durissus cumanensis and compared them to different Crotalus sp sequences available on databases obtaining concordance between the toxins amplified and those reported. Our strategy allows the use of lyophilized venom to obtain complete toxin sequences from samples collected in the field and the study of poorly characterized venoms in challenging environments.

Influencia del polimorfismo rs11549465 de HIF-1α en los niveles de hemoglobina y lactato en pacientes de cirugía cardiovascular / Influence of HIF-1α rs11549465 polymorphism on hemoglobin and lactate levels in cardiovascular surgery patients

Resumen Introducción. La anemia perioperatoria es una complicación común de la cirugía cardiovascular. Pacientes con el alelo T del polimorfismo rs11549465 de HIF-1α podrían tener niveles alterados de hemoglobina y lactato antes, durante y después de la cirugía, en comparación con los del ancestral. Esto, por un aumento en la estabilidad de HIF-1α causado por este. Objetivo. Describir la frecuencia del alelo T en pacientes de cirugía cardiovascular programada y su relación con los niveles de hemoglobina y lactato. Materiales y métodos: Se aisló ADN de 84 pacientes de cirugía cardiovascular para genotipificación por secuenciación de Sanger y se recolectaron características demográficas y clínicas. Resultados. La frecuencia del alelo T fue 0.066 (IC95%: 0.037-0.114). No hubo diferencias significativas en los niveles de hemoglobina y lactato preoperatorios, intraoperatorios y posoperatorios entre pacientes con alelo T y aquellos con alelo ancestral. Conclusión. La frecuencia del alelo T fue menor que la esperada, de acuerdo con otros estudios en poblaciones similares de voluntarios sanos y no mostró diferencias significativas con algunas poblaciones asiáticas, ni con un grupo de pacientes con infarto agudo de miocardio. Parece que la genotipificación de rs11549465 en pacientes de cirugía cardiovascular no representó un método de estratificación de riesgo de anemia en este grupo.

Abstract Introduction: Perioperative anemia is a common complication of cardiovascular surgery. Patients who present the T allele of the HIF-1α rs11549465 polymorphism may have altered hemoglobin and lactate levels before, during and after surgery, compared to the wild-type allele, due to an increased stability of HIF-1α caused by this allele. Objective: To describe the frequency of the T allele in patients scheduled for cardiovascular surgery, and its relationship with hemoglobin and lactate levels. Materials and methods: DNA was isolated from 84 cardiovascular surgery patients for genotyping by Sanger sequencing. Demographic and clinical characteristics were collected. Results: The frequency of the T allele was 0.066 (95%CI: 0.0370.114). No significant differences were observed in preoperative, intraoperative, and postoperative hemoglobin and lactate levels between patients with the T allele and those with the wild-type allele. Conclusion: The frequency of the T allele is lower than expected according to other studies in healthy volunteers. No significant differences were observed in some Asian populations, nor in a group of acute myocardial infarction patients. Apparently, rs11549465 genotyping in cardiovascular surgery patients is not a valid risk stratification method for anemia in this group.

Semiconductor Whole Exome Sequencing for the Identification of Genetic Variants in Colombian Patients Clinically Diagnosed with Long QT Syndrome.

BACKGROUND AND OBJECTIVE: Inherited long QT syndrome (LQTS) is a cardiac channelopathy characterized by a prolongation of QT interval and the risk of syncope, cardiac arrest, and sudden cardiac death. Genetic diagnosis of LQTS is critical in medical practice as results can guide adequate management of patients and distinguish phenocopies such as catecholaminergic polymorphic ventricular tachycardia (CPVT). However, extensive screening of large genomic regions is required in order to reliably identify genetic causes. Semiconductor whole exome sequencing (WES) is a promising approach for the identification of variants in the coding regions of most human genes. METHODS: DNA samples from 21 Colombian patients clinically diagnosed with LQTS were enriched for coding regions using multiplex polymerase chain reaction (PCR) and subjected to WES using a semiconductor sequencer. RESULTS: Semiconductor WES showed mean coverage of 93.6 % for all coding regions relevant to LQTS at >10× depth with high intra- and inter-assay depth heterogeneity. Fifteen variants were detected in 12 patients in genes associated with LQTS. Three variants were identified in three patients in genes associated with CPVT. Co-segregation analysis was performed when possible. All variants were analyzed with two pathogenicity prediction algorithms. The overall prevalence of LQTS and CPVT variants in our cohort was 71.4 %. All LQTS variants previously identified through commercial genetic testing were identified. CONCLUSION: Standardized WES assays can be easily implemented, often at a lower cost than sequencing panels. Our results show that WES can identify LQTS-causing mutations and permits differential diagnosis of related conditions in a real-world clinical setting. However, high heterogeneity in sequencing depth and low coverage in the most relevant genes is expected to be associated with reduced analytical sensitivity.

The outcome of free tissue transfers in patients with hematological diseases: 20-year experiences in single microsurgical center.

BACKGROUND: Free tissue transfers performed in patients with hematological diseases represent significant challenges for micro-surgeons. There are rare literatures that address the outcome in these patients. Therefore, we collected our database, analyzed the outcome, reliability, and related-management of microsurgical technique in the patients with hematological diseases. METHODS: A retrospective chart review of 20 patients with hematological disorders who received free tissue transfers during 20-years period in a single microsurgical center was done. Eleven patients who received head and neck reconstruction were found to have hyperfibrinogenemia. Seven patients with reactive thrombocytosis after trauma, and two patients with leukemia had soft tissue defects in the upper and lower extremities. Twenty-six flaps were used for free tissue transfers. Intra-operatively all patients received intravenous 5,000 Ud of heparin post immediate reperfusion. Anti-coagulant medication such as Dextran-40 or prostaglandin-E1 (PGE1) was given postoperatively. RESULTS: Twenty-three of the 26 free flaps survived without vascular compromise. Intra-operatively all patients received intravenous 5,000 Ud of heparin post immediate reperfusion, and anti-coagulant medication such as Dextran-40 or prostaglandin-E1 was given to the patients postoperatively. The three failed cases were found in patients with hyperfibrinogenemia and needed further reconstruction with another flap. The overall success rate was 88.5% (23/26). CONCLUSIONS: Hematologic disorder is not a predicted factor of free flap failure. The key factors for success flap survival in patients with hematologic disorders include preoperative knowledge of the medical condition and monitoring potential post-operative complications, aggressive hematologist consultations, and meticulous non-traumatic surgical anastomosis.

Entendiendo las bases genéticas de la enfermedad coronaria - Polimorfismos en la enzima convertidora de angiotensina / Understanding the genetic basis of coronary heart disease - Polymorphisms in angiotensin converting enzyme

En esta edición de la Revista Colombiana de Cardiología, Jaramillo y colaboradores reportan el estudio de las frecuencias de un polimorfismo de inserción/deleción (I/D) en un elemento intrónico del gen codificante de la enzima convertidora de angiotensina (ECA) y su relación con el riesgo de enfermedad coronaria. La hipótesis de la influencia del alelo D en el riesgo de enfermedad cardiovascular se basa en una correlación observada entre la presencia de dicho alelo y los niveles elevados de ECA. Se piensa que éstos generarán mayores niveles de angiotensina II a partir de angiotensina I y degradarán bradiquinina, afectando el equilibrio hemodinámico y desencadenando complicaciones cardiacas y/o renales. El análisis de este polimorfismo se ve complicado por el hecho de que es considerado un locus de un carácter cuantitativo (quantitative trait locus) que modifica el nivel de expresión de ECA. Sin embargo, no se conoce el mecanismo molecular que explica la correlación entre la presencia del alelo D de ECA y los niveles elevados de ésta en el plasma. De hecho, se ha demostrado que hay al menos cuatro polimorfismos en el gen de ECA que pueden afectar su expresión y que, en sujetos de ascendencia europea, hay un desequilibrio de ligamiento muy alto entre el alelo D de ECA y algunos de estos elementos . Por el contrario, en familias de Nigeria (y posiblemente en otras poblaciones), no existe un desequilibrio de ligamiento tan alto y los niveles de ECA no muestran correlación significativa con el alelo D . Debido a la falta de conocimiento sobre los mecanismos de regulación de expresión del gen de ECA, es posible que el alelo D de ECA sólo se correlacione con la expresión de ECA en ciertas poblaciones (donde existe un desequilibrio de ligamiento con otros elementos con mayor efecto sobre la expresión del gen), hecho que podría explicar las inconsistencias que se observan en la relación entre el alelo D de ECA y el riesgo de enfermedad cardiovascular en diferentes poblaciones.