Infección tuberculosa latente en personal de salud de las Américas / Latent tuberculosis infection in health personnel in America

Introducción. Según la Organización Mundial para la Salud, un tercio de la población mundial tiene tuberculosis latente, considerando al personal de salud como uno de los grupos de riesgo con mayor tasa de prevalencia. Objetivo. En el presente estudio se realizó una revisión bibliográfica de la evidencia existente acerca de la situación epidemiológica de la infección tuberculosa latente en trabajadores de salud en las Américas. Metodología. Este estudio comprende una revisión sistemática de estudios transversales, metaanálisis y de cohorte, publicados en los últimos 10 años. Se seleccionaron los estudios que cumplieron con criterios de inclusión y de calidad. Resultados. Se seleccionaron 15 de 288 estudios encontrados, pertenecientes a 8 países de América. La prevalencia oscilaba entre 15% y 62.1%. La prevalencia de infección tuberculosa latente en nueve estudios es mayor a la de la población global, en cuatro es similar y en uno es inferior. Conclusión. La prevalencia de tuberculosis sigue siendo mayor en los trabajadores de salud que en la población general. Esto afecta mayoritariamente a las mujeres entre los 35 y 43 años que han laborado por más de 10 años en centros penitenciarios o centros de atención primaria.

Introduction. According to the World Health Organization, a third of the world's population has latent tuberculosis, considering health personnel as a risk group, with a higher prevalence rate. Objective. A bibliographic review of the existing evidence on the epidemiological situation of latent tuberculosis infection in health workers in the Americas was carried out. Methods. This study includes a systematic review of cross-sectional, meta-analysis and cohort studies, published in the last 10 years. The studies that met the inclusion and quality criteria were selected. Results. Fifteen of the 288 studies found in eight countries in the Americas were selected, with prevalence ranging from 15% to 62.1%. The prevalence of latent tuberculosis infection in nine studies is higher than the prevalence in the global population, in four it is similar and one is lower. Conclusion. The prevalence of tuberculosis remains higher in health workers than in the general population. This mostly affects women between the ages of 35 and 43 who have worked for more than 10 years in prisons or primary care centers.

ELF4 Is a Target of miR-124 and Promotes Neuroblastoma Proliferation and Undifferentiated State.

13-Cis-retinoic acid (RA) is typically used in postremission maintenance therapy in patients with neuroblastoma. However, side effects and recurrence are often observed. We investigated the use of miRNAs as a strategy to replace RA as promoters of differentiation. miR-124 was identified as the top candidate in a functional screen. Genomic target analysis indicated that repression of a network of transcription factors (TF) could be mediating most of miR-124's effect in driving differentiation. To advance miR-124 mimic use in therapy and better define its mechanism of action, a high-throughput siRNA morphologic screen focusing on its TF targets was conducted and ELF4 was identified as a leading candidate for miR-124 repression. By altering its expression levels, we showed that ELF4 maintains neuroblastoma in an undifferentiated state and promotes proliferation. Moreover, ELF4 transgenic expression was able to counteract the neurogenic effect of miR-124 in neuroblastoma cells. With RNA sequencing, we established the main role of ELF4 to be regulation of cell-cycle progression, specifically through the DREAM complex. Interestingly, several cell-cycle genes activated by ELF4 are repressed by miR-124, suggesting that they might form a TF-miRNA regulatory loop. Finally, we showed that high ELF4 expression is often observed in neuroblastomas and is associated with poor survival. IMPLICATIONS: miR-124 induces neuroblastoma differentiation partially through the downregulation of TF ELF4, which drives neuroblastoma proliferation and its undifferentiated phenotype.

Cutaneous melanoma in patients from western Mexico: Clinical pathology characteristics and their relationship to prognosis.

BACKGROUND/OBJECTIVE: Melanoma is the third most frequent malignant neoplasm in skin. The majority of information available comes from studies performed in Caucasian populations. Our objective was to investigate the clinico-pathological characteristics in Mexican patients with cutaneous melanoma and the relationship these characteristics had to prognosis. METHODS: A retrospective study included patients with a histopathological diagnosis of melanoma who were attended at a tertiary level Dermatology Institute over a 10-year period. Age, gender, anatomical location; histopathological subtype, Breslow thickness, Clark level; presence of ulceration, metastasis, anatomical-pathological stage and survival were investigated. To assess the data, descriptive statistics, chi-squared or the Fisher exact test and Kaplan-Meier curves were used. RESULTS: There were 323 patients included. The overall survival rate was 77% with an average follow-up of 7 years. The lowest survival was statistically related to the following: higher age (>65 years), localisation in palms/soles, histopathological nodular subtype, presence of ulceration, Breslow thickness >4.0 mm, Clark level V, the presence of metastasis and stage IV disease. CONCLUSIONS: Our results relay the characteristics and prognosis of patients with the diagnosis of cutaneous melanoma in western Mexico.

Psoriasis in Children and Adolescents: Epidemiological Study of 280 Patients from Mexico.

BACKGROUND: Psoriasis in children and adolescents has not been well studied in Mexico. OBJECTIVE: To study the epidemiological characteristics of psoriasis in this age group. METHODS: This is a retrospective study in an academic, tertiary care dermatology center from January 1999 to December 2014. We included patients ≤ 18 years of age, with clinical and histopathological diagnosis of psoriasis. We recorded the following information: gender, age, disease duration, clinical variant, nail involvement, treatment, and family history. Descriptive and inferential statistics were used for analysis. RESULTS: Of 2,491 patients with psoriasis, 280 were ≤ 18 years of age, resulting in a prevalence of 11%. There was female predominance and the mean age was 11.5 years. Disease duration was 18 ± 34 months. Plaque psoriasis was the most common form, comprising 191 cases (68%). Nail involvement occurred in only 15 patients (5%). Topical treatment was given to 177 patients (63%). Only 14 cases (5%) had a family history of psoriasis. These variables did not differ when children were compared with adolescents, except in those with a shorter disease duration (13 ± 19 vs. 24 ± 29 months; p = 0.0004). CONCLUSIONS: We found a higher prevalence of psoriasis than previously published studies in this age group and a lower frequency of nail involvement and family history of psoriasis.

Differential expression of solute carrier family 11a member 1 and inducible nitric oxide synthase 2 in skin biopsies from leprosy patients.

BACKGROUND: Leprosy is a chronic granulomatous infection caused by Mycobacterium leprae, an intracellular parasite that resides within macrophages and cannot be eliminated effectively. Solute carrier family 11a member 1 (Slc11a1) and inducible nitric oxide synthase (iNOS), both expressed in macrophages, play major roles in host defense against several intracellular pathogens. However, the roles of these molecules in natural infection with M. leprae remain unknown. OBJECTIVE: We aimed to investigate the expression of Slc11a1 and iNOS in macrophages (CD68+ cells) infiltrating skin lesions in leprosy. METHODS: Skin biopsies from 48 Mexican patients of leprosy [(33 lepromatous (LL), 15 tuberculoid (TT)] and from 10 healthy controls, were subjected to immunohistochemistry to determine expression of CD68, Slc11a1 and iNOS. RESULTS: We found a high expression of Slc11a1 and iNOS in most lepromatous leprosy samples. In tuberculoid leprosy samples, Slc11a1 expression was moderate or low, and that of iNOS was almost always low. In addition, Slc11a1 and iNOS expression levels were positively associated with bacillary loads in lepromatous leprosy lesions (P=0.05). CONCLUSIONS: These observations suggest that M. leprae infection promotes the expression of Slc11a1 and iNOS in macrophages and that lepromatous leprosy can occur despite this response.

Eccrine porocarcinoma: epidemiologic and histopathologic characteristics.

BACKGROUND: Porocarcinoma is a rare tumor, representing 0.005% of all malignant epithelial neoplasms. The majority of publications are single case reports. The objective of this study was to describe the epidemiologic and histopathologic characteristics of patients diagnosed with eccrine porocarcinoma. METHODS: A retrospective study was carried out from January 1994 to December 2010. Cases with a histopathological diagnosis of eccrine porocarcinoma were included. The investigated variables were frequency, gender, age, time of evolution, localization, morphology, referral clinical diagnosis, and histopathology patterns. The information was analyzed using descriptive statistics. RESULTS: During this 17-year period, 33 cases diagnosed with eccrine porocarcinoma were detected. Female gender was predominant with 64% cases. The average age was 74 ± 12 years. The most frequent location was the head with 37% cases; the most common observed morphology was nodular, in 46%. The main referral diagnosis was squamous cell carcinoma in 67% of cases. With regard to the histopathology characteristics, necrosis predominated in 64% cases, comedonecrosis in 45% cases, squamous differentiation in 42% cases, and melanocyte colonization in 21%. CONCLUSIONS: Our series presents some clinical and histopathology differences with previously reported, such as the most frequent localization in the head and the presence of melanocyte colonization.