Impact of hyperparathyroidism on allograft histology and function after kidney transplantation: Rethinking its causal role in graft dysfunction.

INTRODUCTION: The causal relationship between hyperparathyroidism and kidney graft dysfunction remains inconclusive. Applying Bradford-Hill's temporality and consistency causation principles, we assessed the effect of parathyroid hormone (iPTH) on graft histology and eGFR trajectory on kidney transplant recipients (KTRs) with normal time-zero graft biopsies. METHODS: Retrospective cohort study evaluating the effect of hyperparathyroidism on interstitial fibrosis and tubular atrophy (IF/TA) development in 1232 graft biopsies. Pre-transplant hyperparathyroidism was categorized by KDIGO or KDOQI criteria, and post-transplant hyperparathyroidism by iPTH >1× and >2× the URL 1 year after transplantation. RESULTS: We included 325 KTRs (56% female, age 38 ± 13 years, follow-up 4.2 years [IQR: 2.7-5.8]). Based on pre-transplant iPTH levels, 26% and 66% exceeded the KDIGO and KDOQI targets, respectively. There were no significant differences in the development of >25% IF/TA between KTRs with pre-transplant iPTH levels above and within target range according to KDIGO (53% vs. 62%, P = .16, HR.94 [95% CI:.67-1.32]) and KDOQI (60% vs. 60%, P = 1.0, HR 1.19 [95% CI:.88-1.60]) criteria. Similarly, there were no differences when using 1 year post-transplant iPTH cut-offs > 88 pg/mL (58% vs. 64%, P = .33) and > 176 pg/mL (55% vs. 62%, P = .19). After adjusting for confounders, no significant differences were observed in eGFR trajectories among the iPTH strata. CONCLUSION: In young KTRs who received a healthy graft, no association was found between increased pre- and post-transplant iPTH levels and graft dysfunction, as assessed histologically and through eGFR trajectory. The concept of hyperparathyroidism as a risk factor for graft dysfunction in recipients at low risk requires reevaluation.

Integrative Taxonomy Reveals Hidden Diversity in the Aloina catillum Complex (Pottiaceae, Bryophyta).

Aloina catillum is a variable moss typical of xerophytic environments in the Neotropics, characterized against other closely allied Aloina species with well-differentiated leaf border by its setae twisted to the left throughout. In order to clarify its variability and its relationships with the allied species with differentiated leaf border A. brevirostris, A. obliquifolia, and A. rigida, we performed an integrative study including sequence data from four markers (nuclear ITS, plastid atpB-rbcL, trnG, trnL-F), morphometry, and species assembling by automatic partitioning (ASAP) algorithm. Our data suggest that A. catillum consists of at least three species: A. calceolifolia (an earlier name for A. catillum), and two species described here as a new, A. bracteata sp. nov. and A. limbata sp. nov. This latter species includes the specimens previously identified as A. obliquifolia from South America. Additionally, some morphological and molecular variability was also detected in A. limbata, but was not consistent enough to be recognized taxonomically. The study supports the presence of A. brevirostris in the Neotropics and A. rigida is tentatively excluded from South America. Full descriptions of the A. catillum s.l. species and a diagnostic key to this complex in South America are provided.

Adhesion factors and antimicrobial resistance of Escherichia coli strains associated with colibacillosis in piglets in Colombia.

Background and Aims: The pathogenicity of Escherichia coli is determined by the presence of genes that mediate virulence factors such as adherence capacity and toxin production. This research aimed to identify the adhesion factors and antibiotic resistance capacity of E. coli strains associated with diarrhea in piglets in Colombia. Materials and Methods: Presumptive E. coli strains were isolated from the rectal swabs of piglets in swine farms between 4 and 40 days of age with evidence of diarrhea. Presumptive E. coli strains were tested for antibiotic resistance. The hemolytic capacity of presumptive E. coli strains was measured and molecularly identified. Strains confirmed as hemolytic E. coli was evaluated for the presence of five adhesion factors (F4, F5, F6, F18, and F41) and resistance to 11 antibiotics. Results: Fifty-two putative E. coli strains were isolated, six of which showed a hemolytic capacity. The hemolytic strains were molecularly identified as E. coli. Adhesive fimbriae were found in five of six ß-hemolytic E. coli isolates. Combinations of the adhesion factors F6-F18 and F6-F41 were linked to antibiotic resistance capacity. Conclusion: The phenomenon of E. coli strains resistant to multiple antibiotics on pig farms represents a constant risk factor for public health and pig production.

COVID-19 patients with high TNF/IFN-γ levels show hallmarks of PANoptosis, an inflammatory cell death.

TNF and IFN-γ trigger cell damage during SARS CoV-2 infection; these cytokines can induce senescence and a cell death process called PANoptosis. This study included 138 vaccine-naïve COVID-19 patients, who were divided into four groups (Gp) according to the plasma level of TNF and IFN-γ (High [Hi] or Normal-Low [No-Low]), Gp 1: TNFHi/IFNγHi; Gp 2: TNFHi/IFNγNo-Low; Gp 3: TNFNo-Low/IFNγHi; and Gp 4: TNFNo-Low/IFNγNo-Low. Thirty-five apoptosis-related proteins and molecules related to cell death and senescence were evaluated. Our results showed that groups did not display differences in age and comorbidities. However, 81% of the Gp 1 patients had severe COVID-19, and 44% died. Notably, the p21/CDKN1A was increased in Gp 2 and Gp 3. Moreover, Gp 1 showed higher TNFR1, MLKL, RIPK1, NLRP3, Caspase 1, and HMGB-1 levels, suggesting elevated TNF and IFN-γ levels simultaneously activate diverse cell death pathways because it is not observed when only one of these cytokines is increased. Thus, high TNF/IFN-γ levels are predominant in severe COVID-19 status, and patients display cell alterations associated with the activation of diverse cell death pathways, including a possible senescent phenotype.

Tratamiento quirúrgico del divertículo de Zenker; un caso clínico; Hospital Militar Central de La Paz (COSSMIL) gestión 2022 / Surgical treatment of Zenker's diverticulum, a Clinical Case Central Military Hospital of La Paz (COSSMIL) gestión 2022

Se presenta un caso clínico de una paciente de 66 años de edad masculino que acude a nuestro hospital (COOSMIL), después de hacer una anamnesis donde el paciente manifiestas molestias como tos, regurgitación y mal alientos (halitosis) y se le hace exámenes complementarios y se llega a un diagnóstico de divertículo faringo-esofágico o Zenker. Esta patología no es muy frecuente, pero se presenta en ancianos por una alteración anatomo-funcional que es un debilitamiento del músculo esofágico Hay tres divertículos esofágicos de los cuales el divertículo de Zenker es el más común aunque es relativamente raro que se presente, en la mayoría de las personas en edad seniles. Después de analizar el tamaño y forma del divertículo de este paciente se toma la decisión de una intervención quirúrgica el más acertado por el tamaño que mide es la diverticulectomia este tratamiento quirúrgico actualmente se continúa realizando en esta patología y con buen pronóstico de vida del paciente. Actualmente, el paciente se encuentra en buen estado salud y su recuperación es favorable desde la operación hasta el momento.

A case of a male patient of 66 years old was referred to our hospital (COSSMIL), after making an anamnesis in which the patient manifested cough, regurgitation and bad breath (halitosis). After further examination a the diagnosis is pharyngo-esophageal diverticulum or Zenker. This condition is rare, but sometimes it happens in elders due to an anatomical and functional alteration caused by is an esophagus muscle weakening. There are three esophageal diverticula in which the Zenker diverticulum is the most common but relatively rarely to occur in elder people. Before analyzing the size and shape of the diverticulum in this patient, the decision is proceed with surgery, the most recommended solution for measuring the size of the diverticulectomy. is The surgical treatment is still being applied in this pathology, with a high probability of success. Currently, the patient is in good health and the recovery from surgery is favorable so far.

Trends and outcomes of trauma patients positive to marijuana and cocaine.

PURPOSE: Substance misuse has long been recognized as a major predisposing risk factor for traumatic injury. However, there still exists no clear scientific consensus regarding the impact of drug use on patient outcomes. Therefore, this study aims to evaluate the demographic profile, hospital-course factors, and outcomes of trauma patients based on their toxicology. METHODS: This is a non-concurrent cohort study of 3709 patients treated at the Puerto Rico Trauma Hospital during 2002-2018. The sample was divided into four groups according to their toxicology status. Statistical techniques used included Pearson's chi-square test, Spearman correlation, and negative binomial and logistic regressions. RESULTS: Admission rates for marijuana (rho = 0.87) and marijuana and cocaine positive (rho = 0.68) patients increased. Positive toxicology patients underwent surgery more often than negative testing patients (marijuana: 68.7%, cocaine: 65.6%, marijuana & cocaine: 69.8%, negative: 57.0%). Among patients with non-penetrating injuries, a positive toxicology for cocaine or marijuana was linked to a 48% and 42% increased adjusted risk of complications, 37% and 27% longer TICU LOS, and 32% and 18% longer hospital LOS, respectively. CONCLUSION: Our results show an association between positive toxicology for either marijuana, cocaine, or both with higher need for surgery. Additionally, our results show an increase in complications, TICU LOS, and hospital LOS among non-penetrating trauma patients testing positive for marijuana or cocaine. Therefore, this study provides valuable information on the clinical profile of patients with positive toxicology, suggesting they might benefit from more aggressive management.

Socio-Demographic and Medical Characteristics of Patients With Odontogenic Infection Admitted to the Adult University Hospital in Puerto Rico: A Cross-sectional Study.

OBJECTIVE: We aimed to estimate the overall distribution of odontogenic infection by socio-demographic and medical characteristics in patients admitted to the Adult University Hospital (AUH) in Puerto Rico (PR). METHODS: A cross-sectional study was undertaken with the medical charts of 129 patients (≥21 years) with odontogenic infection who had been admitted (2011-2015) to the AUH and treated by the Oral and Maxillofacial Surgery Post - graduate Program of the University of PR. The patients were selected from the hospital's billing database after having been identified using the International Classification of Diseases (9th and 10th revisions). The study variables included age, gender, municipality of residence, medical insurance, infection etiology, surgical and antibiotic treatments, length of stay (LOS), and the presence of diabetes. Descriptive and frequency statistics were calculated for all the variables; chi-squared, Kruskal-Wallis, Kendall tau, and Mann-Whitney tests were performed. A P < .05 was considered statistically significant. RESULTS: The mean age of the subjects was 40.36 (SD: 14.74) years, and they ranged in age from 21 to 81 years; the majority were enrolled in the public health insurance plan of PR. The leading cause of infection was dental caries. Diabetes was associated with longer LOSs; P < .01. CONCLUSION: In our study, the relative frequency of admitted patients with an odontogenic infection, most of them with low income, increased over time with dental caries being the principal cause of infection.

Work orientation and flourishing life in twelve Ibero-American countries / Orientación laboral y vida floreciente en doce países iberoamericanos

Abstract Introduction/Objetive: Work orientation includes the individual's beliefs regarding the role of work in his/her life as a whole and what they are searching for in their careers. There are three types of orientation to work: job, career, and vocation. Work orientation has the distinction of examining how work connects with people's lives and is, therefore, an appropriate construct for evaluating the impact of work on human flourishing. The aims of this study are first to explore work orientation in twelve Ibero-American countries; and second, to investigate whether work orientation affects flourishing in the lives of adults in twelve Ibero-American countries. Method: A total of 3000 adults participated in this study. The University of Pennsylvania Work-Life Questionnaire was used to evaluate the type of relationship that employees reported having with their work, according to the distinctions between job, career, and calling. A 12-item version of the Multidimensional Flourishing Scale was used to measure three aspects of flourishing: social, psychological, and emotional well-being. Results: Most participants reported a high level of calling in their work orientation. In most countries, those with a calling orientation reported higher levels of social and psychological well-being than those with a job orientation. The results indicate a clear relationship between a calling orientation and social and psychological well-being. Conclusion: This research is the first to compare the relationship between work-orientation and flourishing in Ibero-America. The findings help us understand that work-orientation is not a secondary aspect of a person's life but has fundamental implications in the lives of workers.

Resumen Introducción/Objetivo: La orientación laboral incluye las creencias del individuo sobre el papel del trabajo en su vida como un todo y lo que está buscando en su carrera. La orientación laboral examina cómo el trabajo se conecta con la vida de las personas y es un constructo apropiado para evaluar el efecto del trabajo en el florecimiento humano. Se propone explorar la orientación laboral en 12 países iberoamericanos; e investigar si la orientación laboral afecta el florecimiento humano. Método: Tres mil adultos participaron en este estudio. Se utilizó el Work-Life Questionnaire para evaluar el tipo de relación que los empleados informan tener con su trabajo, de acuerdo con las distinciones entre trabajo, carrera y vocación. Se utilizó la Escala de Florecimiento Multidimensional para medir tres aspectos del florecimiento: bienestar social, psicológico y emocional. Resultados: La mayoría de los participantes informaron un alto nivel de orientación laboral como vocación. En la mayoría de los países, aquellos que trabajan por vocación informaron niveles más altos de bienestar social y psicológico que aquellos que trabajan solo por una motivación económica. Conclusiones: Esta investigación es la primera en comparar la relación entre la orientación al trabajo y el florecimiento humano en Iberoamérica. Los hallazgos nos ayudan a comprender que la orientación al trabajo no es un aspecto secundario de la vida de una persona, sino que tiene implicaciones fundamentales en los trabajadores.

Genetic analysis of patients with nonsyndromic and syndromic retinitis pigmentosa in Puerto Rico: a genetic legacy.

BACKGROUND: Retinitis pigmentosa (RP) is a genetically heterogeneous group of diseases characterized by complete progressive vision loss; it has a prevalence of approximately one in 2500-7000. Patients with RP may have isolated findings, or the disorder can occur as part of a constellation of other abnormalities that, together, are known as syndromic RP. The aim of this study was to describe the results of a genetic analysis of a cohort of Puerto Ricans with a clinical diagnosis of RP. MATERIALS AND METHODS: This was a cross-sectional study with a cohort of 224 Puerto Rican patients who carried a clinical diagnosis of RP. During a local (Puerto Rico) RP convention, the patients were offered genetic analysis. Volunteering patients signed consent forms for the study. Saliva samples were obtained and analyzed. Patients were evaluated by at least one of the authors. Patients with pathogenic mutation(s), according to the panel, were classified as positive and sorted based on the results. RESULTS: Of 224 patients, 161 (71.9%) had pathogenic gene variants associated with IRDs. 54.5% (122/224) of cases were conclusive. More than half (72/122) of these cases are explained by mutations in the BBS1, PDE6B, CNGB1, and USH2A genes. Genetic analysis showed that the highest rate of pathogenic variants in our cohort was found in the BBS1 gene. CONCLUSIONS: This was the first genetic analysis in Puerto Rico of patients with RP. The most common mutation associated with RP was found in the BBS1 gene. The frequency of other pathogenic variants related to RP in Puerto Rico were different to those reported in Spain.

Diagnostic criteria for enduring sexual dysfunction after treatment with antidepressants, finasteride and isotretinoin.

BACKGROUND: A set of enduring conditions have been reported in the literature involving persistent sexual dysfunction after discontinuation of serotonin reuptake inhibiting antidepressants, 5 alpha-reductase inhibitors and isotretinoin. OBJECTIVE: To develop diagnostic criteria for post-SSRI sexual dysfunction (PSSD), persistent genital arousal disorder (PGAD) following serotonin reuptake inhibitors, post-finasteride syndrome (PFS) and post-retinoid sexual dysfunction (PRSD). METHODS: The original draft was designed using data from two published case series (Hogan et al., 2014 and Healy et al., 2018), which represent the largest public collections of data on these enduring conditions. It was further developed with the involvement of a multidisciplinary panel of experts. RESULTS: A set of criteria were agreed upon for each of the above conditions. Features of PSSD, PFS and PRSD commonly include decreased genital and orgasmic sensation, decreased sexual desire and erectile dysfunction. Ancillary non-sexual symptoms vary depending on the specific condition but can include emotional blunting and cognitive impairment. PGAD presents with an almost mirror image of unwanted sensations of genital arousal or irritability in the absence of sexual desire. A new term, post-SSRI asexuality, is introduced to describe a dampening of sexual interest and pleasure resulting from a pre-natal or pre-teen exposure to a serotonin reuptake inhibitor. CONCLUSIONS: These criteria will help in both clinical and research settings. As with all criteria, they will likely need modification in the light of developments.

Estudio transoperatorio de tumores limítrofes de ovario. Características que pueden repercutir en el diagnóstico / The intraoperative study in borderline ovarian tumors. Characteristics that can impact the diagnosis

Resumen OBJETIVO: Determinar el porcentaje de concordancia del estudio transoperatorio con el diagnóstico definitivo de tumores limítrofes de ovario. MATERIALES Y MÉTODOS: Estudio observacional, transversal, retrospectivo y descriptivo efectuado en el Hospital de Ginecoobstetricia 4 Luis Castelazo Ayala, Ciudad de México, en pacientes operadas entre el 1 de enero de 2018 y el 31 diciembre de 2020 de un tumor abdominopélvico, con examen transoperatorio de tumor limítrofe de ovario. El estudio transoperatorio se evaluó como prueba diagnóstica y el diagnóstico definitivo como patrón de referencia para establecer la concordancia del primero con el diagnóstico definitivo de tumores limítrofes de ovario. RESULTADOS: Se analizaron 68 tumores limítrofes de ovario, entre los diagnosticados en el estudio transoperatorio y el definitivo. Se encontraron 59 casos con diagnóstico definitivo de tumor limítrofe de ovario. La concordancia con el estudio transoperatorio fue de 63.2%. Se sobrediagnosticaron 2 de 68 pacientes (2.9%) y se subdiagnosticaron 23 de 68 (33.8%). CONCLUSIONES: La concordancia obtenida es semejante a lo reportado en la bibliografía internacional. Los tumores mucinosos mayores de 10 cm son subdiagnosticados con mayor frecuencia debido a su extensión.

Abstract OBJECTIVE: To determine the percentage of concordance of the transoperative study with the definitive diagnosis of borderline ovarian tumors. MATERIALS AND METHODS: Observational, cross-sectional, retrospective and des-criptive study performed at the Hospital de Gineco Obstetricia 4 Luis Castelazo Ayala, Mexico City, in patients operated between January 1, 2018 and December 31, 2020 for an abdominopelvic tumor, with transoperative examination of borderline ovarian tumor. The transoperative study was evaluated as a diagnostic test and the definitive diagnosis as a reference standard to establish the concordance of the former with the definitive diagnosis of borderline ovarian tumors. RESULTS: Sixty-eight borderline ovarian tumors were analyzed, between those diagnosed in the transoperative study and the definitive one. We found 59 cases with definitive diagnosis of borderline ovarian tumor. The concordance with the transoperative study was 63.2%. Two of 68 patients (2.9%) were overdiagnosed and 23 of 68 (33.8%) were underdiagnosed. CONCLUSIONS: The concordance obtained is like that reported in the international literature. Mucinous tumors larger than 10 cm are most frequently underdiagnosed due to their extension.

Prevalence of Short Root Anomaly in a Group of Puerto Ricans.

OBJECTIVE: To estimate the prevalence of short root anomaly (SRA) in a group of Puerto Ricans at the Advanced Education Program in Orthodontics of the University of Puerto Rico. METHODS: A cross-sectional study was conducted with digital panoramic x-rays of 203 patients (112 females and 91 males; mean age: 17 years) in Puerto Rico. Utilizing the modified Lind's method, 406 maxillary right and left central incisors (1) were measured and evaluated for SRA. Root and crown length and R/C ratio were compared by sex and side. Linear regression was used to evaluate the associations between the R/C ratio and age, sex, and side (right/left). All the statistical analyses were evaluated using significance level of .05 (2). RESULTS: The prevalence of SRA was 0.49%. The average root and crown lengths for the maxillary right and left central incisors were 19.47 and 10.28 mm, respectively. Sex was associated with root and crown length, not with the R/C ratio. No differences were observed in the R/C ratio by the side. There were no significant associations between age, sex, and side and R/C ratio in the multivariate analysis. CONCLUSION: The prevalence of SRA in our population is lower than any reported in the literature. The R/C ratio in our Hispanic population was the highest compared with those of other ethnicities. Neither the sex nor the side of the incisor was associated with the R/C ratio. These findings are contrary to those of prior reports stating that males have higher R/C ratios than females.

A Retrospective Cohort Study on Health Insurance: Related Disparities in Trauma Patients After Penetrating Injuries: 2000-2014.

OBJECTIVE: Although the lack of health insurance has been linked to poor health outcomes in several diseases, this relationship is still understudied in trauma. There exist differences between the Puerto Rico health care system and that of the United States. We therefore aimed to assess mortality disparities related to insurance coverage at the Puerto Rico Trauma Hospital (PRTH). METHODS: A retrospective cohort study of patients who sustained penetrating injuries (presenting at the PRTH from 2000 to 2014) was performed. Individuals were classified by their insurance status. Study variables comprised demographics, clinical characteristics and outcomes. A logistic regression analysis was performed to identify the association between health insurance status and risk of dying. RESULTS: Patients with public health insurance experienced more complications than did individuals who had private health insurance (PrHI) or who were uninsured. This group had longer durations of mechanical ventilation and spent more time in the hospital than did patients who had PrHI or who were uninsured. However, uninsured patients with gunshot wounds were 54% (adjusted odds ratio = 1.54; 95% CI: 1.01, 2.36) more likely to die than were their counterparts who had PrHI. CONCLUSION: Our study suggests that having health insurance could reduce a given patient mortality risk in trauma settings. More studies with larger samples are warranted to confirm these findings. If these findings hold true, then providing equitable access to health services for the entire population could prevent patients suffering trauma from having premature, preventable deaths.

Participation of angiotensin-(1-7) in exercise-induced analgesia in rats with neuropathic pain.

Exercise reduces neuropathic pain in animals and humans. Recent studies indicate that training exercise favors the synthesis and action of angiotensin-(1-7) (Ang-(1-7)), a vasoactive peptide of the renin-angiotensin system (RAS), in various tissues. Interestingly, Ang-(1-7) also relieves neuropathic pain; however, it remains to be elucidated whether exercise mitigates this type of pain through Ang-(1-7). In this study, we investigated the role of Ang-(1-7) in exercise-induced analgesia in a neuropathic pain model. Male Wistar rats were ligated of lumbar spinal nerves (L5 and L6) or sham-operated. Then, they were subjected to acute (2-h) or chronic (4-week) exercise protocols. Tactile allodynia was evaluated before and after each exercise intervention. Microosmotic pumps were implanted subcutaneously for the release of Ang-(1-7) or A779 (selective Mas receptor (MasR; Ang-(1-7) receptor) antagonist). Plasma levels of Ang II and Ang-(1-7) were quantified by HPLC. Spinal nerve ligation (SNL) produced tactile allodynia. Both acute and chronic exercise reversed this neuropathic behavior. A779 treatment prevented the antiallodynic effect induced by each exercise protocol. SNL increased the plasma Ang II/Ang-(1-7) ratio; however, exercise did not modify it. Acute treatment with Ang-(1-7) via MasR mimicked exercise-mediated antinociception. Collectively, these results suggest that activation of the Ang-(1-7)/MasR axis of the RAS represents a potential novel mechanism by which exercise attenuates neuropathic pain in rats.

Presencia de inestabilidad microsatélite en pacientes colombianos con adenocarcinoma colorrectal / Microsatellite instability in Colombian patients with colorectal adenocarcinoma

Resumen Introducción y objetivos: la vía de inestabilidad de microsatélites (IMS) está implicada en la carcinogénesis de un 15 % de carcinomas colorrectales (CCR). La detección de esta alteración tiene relevancia en el pronóstico y en el tratamiento de los pacientes con CCR. El objetivo del presente estudio es determinar la prevalencia de IMS en CCR en una cohorte de pacientes de Bogotá, Colombia. Materiales y métodos: se evaluó por inmunohistoquímica la presencia de homólogo MutL 1 (MLH1), segregación posmeiótica aumentada 2 (PMS2), homólogo mutS 2 (MSH2) y homólogo mutS 6 (MSH6) en muestras de CCR prevenientes de colectomías. Adicionalmente, se analizaron las variables clinicopatológicas. A los casos con pérdida de MLH1 y PMS2 se les evaluó la mutación del gen BRAF. Resultados: en total se incluyeron 86 casos. La mediana de edad de los pacientes con CCR fue de 69 años, 52,3 % fueron hombres. De los pacientes con CCR, 12 (13,9 %) presentaron IMS, de los cuales 10 (83,3 %) tenían ausencia de expresión MLH1/PMS2 y 2 (16,7 %), de MSH2/MSH6. La mediana de edad de los pacientes con CCR e IMS fue de 52 años (45-76,5), 9 eran hombres y el 66,7 % de estos casos se localizaron en el colon derecho. El tipo histológico más frecuente fue adenocarcinoma moderadamente diferenciado (67 %). Los linfocitos infiltrantes al tumor fueron observados en el 83 %, la presencia de infiltrado de tipo Crohn estaba presente en el 42 %. La mutación de BRAF se observó en el 30 % de los pacientes con pérdida de MLH1 y PMS2. Conclusión: la prevalencia de la IMS en nuestra población fue de 14 %, datos similares a los observados en la población norteamericana y europea. Sin embargo, se observa que el 83 % presentó pérdida de expresión del complejo MLH1/PMS2, una prevalencia mayor comparada con otras poblaciones.

Abstract Introduction: The microsatellite instability (MSI) pathway is involved in the carcinogenesis of 15% of colorectal carcinomas (CRC). The detection of this alteration is relevant for the prognosis and treatment of CRC patients. Objective: The aim of this study is to determine the prevalence of MSI in CRC in a cohort of patients in Bogotá, Colombia. Materials and methods: The presence of MLH1, PMS2, MSH2, and MSH6 was evaluated by immunohistochemistry in CRC samples collected during colectomy. Clinicopathological variables were analyzed as well. Cases with loss of MLH1 and PMS2 were evaluated for BRAF gene mutation. Results: A total of 86 cases were included. The median age was 69 years, 52.3% were male. 12 (13.9%) patients had IMS, 10 (83.3%) had absence of MLH1/PMS2 expression and 2 (16.7%) absence of MSH2/MSH6 expression. The median age of patients with IMS was 52 years (45-76.5), of which 9 were male. 66.7% of carcinomas were located in the right colon and the most frequent histological type was moderately differentiated adenocarcinoma (67%). Tumor infiltrating lymphocytes were observed in 83% of the cases, while the presence of Crohn's-like infiltrate was present in 42%. BRAF mutation was observed in 30% of patients with loss of MLH1 and PMS2. Conclusion: The prevalence of IMS in our population was 14%, similar to the data observed in the North American and European populations. However, we observed that 83% had loss of expression of the MLH1/PMS2 complex, a higher prevalence compared to other populations.