Farmacogen\ue9tica de la Tuberculosis: Nuevo modelo de predicci\uf3n de hepatotoxicidad inducida por f\ue1rmacos antituberculosis

Introducci\uf3n: La hepatotoxicidad inducida por f\ue1rmacos antituberculosis (HIFA) es una reacci\uf3n adversa grave y potencialmente fatal del tratamiento de la tuberculosis (TB). Tres de los cuatro f\ue1rmacos utilizados como terapia de primera l\uednea (isoniacida, rifampicina, pirazinamida), han sido asociados a HIFA. Estudios sobre farmacogen\ue9tica de la TB han asociado el desarrollo de HIFA con variaciones en genes de enzimas que metabolizan estos f\ue1rmacos. Objetivos: Debido a que en Argentina la TB es una enfermedad re-emergente y a la elevada prevalencia de HIFA encontrada en pacientes internados, nos propusimos evaluar la posible asociaci\uf3n de factores ambientales y variantes gen\ue9ticas en enzimas que metabolizan f\ue1rmacos anti-TB con el desarrollo de HIFA. Tambi\ue9n, investigar las posibles interacciones gen-gen y gen-ambiente y su asociaci\uf3n con el desarrollo de HIFA, en una poblaci\uf3n de pacientes con TB hospitalizados de la Ciudad de Buenos Aires. M\ue9todos: Se estudiaron 345 pacientes con TB tratados con f\ue1rmacos anti-TB (96 con HIFA). Se analizaron variables cl\uednicas y demogr\ue1ficas tomadas en fichas de datos. Las variaciones gen\ue9ticas en las enzimas N-acetiltransferasa 2 (NAT2), citocromo P450 2E1 (CYP2E1), glutathione S-transferasa theta 1 (GSTT1) y glutathione S-transferasa mu 1 fueron detectadas por reacci\uf3n en cadena de polimerasa (PCR), secuenciaci\uf3n o PCR-RFLP. Para comparar las posibles variables predictoras entre pacientes con y sin HIFA se utiliz\uf3 un an\ue1lisis de regresi\uf3n log\uedstica binaria. Para estudiar las interacciones gen\ue9ticas y ambientales en asociaci\uf3n con HIFA se utiliz\uf3 el m\ue9todo de reducci\uf3n de la dimensionalidad multifactorial (MDR). Resultados: Este estudio mustra que ser acetilador lento (AL) de NAT-2 [OR (IC95%) = 3,02 (1,82-5,00); p<0,001], ser portador de la variante c2 [OR (IC95%) = 2,16 (1,33-3,51); p = 0,002] o ser portador de la variante A4 de CYP2E1 [OR (IC95%) = 2,13 (1,06-4,29); p = 0,049], y ser mujer [OR (IC95%) = 1,94 (1,20 - 3,14); p = 0,006] resultaron variables predictoras independientes para HIFA. Aquellos pacientes AL que adem\ue1s eran portadores de la variante c2 de CYP2E1 tienen un riesgo mayor [OR (IC95%) = 7.07 (3.34-14.95); p <0,001]. Por primera vez, se identific\uf3 una interacci\uf3n sin\ue9rgica (epistasis) entre GSTT1 y CYP2E1 con mayor riesgo de HIFA. A su vez, se describe por primera vez una significativa interacci\uf3n gen (NAT2 y CYP2E1) - ambiente (sexo) con riesgo aumentado de HIFA [TBA = 0,675, (p = 0,001) y CVC = 10/10]. Es decir que el mejor modelo de predicci\uf3n (67,5%) de HIFA contempla las variables NAT2, CYP2E1 y sexo. Conclusiones: HIFA es una reacci\uf3n adversa potencialmente fatal y prevalente (11% de los pacientes tratados) que conduce a la interrupci\uf3n del f\ue1rmaco. En nuestro estudio, se obtuvo un modelo de predicci\uf3n que clasifica adecuadamente al 67,5% de los pacientes con TB en su riesgo de desarrollar HIFA. Dado el n\ufamero considerable de TB en nuestro pa\ueds, las pruebas farmacogen\ue9ticas y una historia cl\uednica completa podr\uedan ser \ufatiles para reconocer a los pacientes con alto riesgo de sufrir hepatotoxicidad. Estos representan datos nacionales e internacionales in\ue9ditos relacionados a HIFA

Histomorphometric analysis of inflammatory response and necrosis in re-implanted central incisor of rats treated with low-level laser therapy

Low-level laser therapy is a tool employed in the management of post-operative inflammation process and in the enhancement of reparative process. The aim of the study was to perform histological evaluation of dental and periodontal ligament of rats central upper-left incisor teeth re-implanted and irradiated with low-level laser (InGaAl, 685 nm, 50 J/cm2) 15, 30, and 60 days after re-implantation. Seventy-two male rats had the central upper left incisor removed and kept for 15 min on dry gauze before replantation. Laser was irradiated over the root surface and empty alveolus prior replantation and over surrounding mucosa after the re-implantation. After histological procedures, all slices were analyzed regarding external resorption area and histological aspects. We observed an increase of root resorption (p < 0.05) in the control group compared to the laser group at 15, 30, and 60 days. These results showed that the laser groups developed less root resorption areas than the control group in all experimental periods. Additionally, histological analysis revealed less inflammatory cells and necrotic areas in laser groups

Preventive Antibacterial Therapy in Acute Ischemic Stroke: A Randomized Controlled Trial

BACKGROUND: Pneumonia is a major risk factor of death after acute stroke. In a mouse model, preventive antibacterial therapy with moxifloxacin not only prevents the development of post-stroke infections, it also reduces mortality, and improves neurological outcome significantly. In this study we investigate whether this approach is effective in stroke patients. METHODS: Preventive ANtibacterial THERapy in acute Ischemic Stroke (PANTHERIS) is a randomized, double-blind, placebo-controlled trial in 80 patients with severe, non-lacunar, ischemic stroke (NIHSS>11) in the middle cerebral artery (MCA) territory. Patients received either intravenous moxifloxacin (400 mg daily) or placebo for 5 days starting within 36 hours after stroke onset. Primary endpoint was infection within 11 days. Secondary endpoints included neurological outcome, survival, development of stroke-induced immunodepression, and induction of bacterial resistance. FINDINGS: On intention-to treat analysis (79 patients), the infection rate at day 11 in the moxifloxacin treated group was 15.4% compared to 32.5% in the placebo treated group (p = 0.114). On per protocol analysis (n = 66), moxifloxacin significantly reduced infection rate from 41.9% to 17.1% (p = 0.032). Stroke associated infections were associated with a lower survival rate. In this study, neurological outcome and survival were not significantly influenced by treatment with moxifloxacin. Frequency of fluoroquinolone resistance in both treatment groups did not differ. On logistic regression analysis, treatment arm as well as the interaction between treatment arm and monocytic HLA-DR expression (a marker for immunodepression) at day 1 after stroke onset was independently and highly predictive for post-stroke infections. INTERPRETATION: PANTHERIS suggests that preventive administration of moxifloxacin is superior in reducing infections after severe non-lacunar ischemic stroke compared to placebo. In addition, the results emphasize the pivotal role of immunodepression in developing post-stroke infections. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN74386719

Is elevated SUA associated with a worse outcome in young Chinese patients with acute cerebral ischemic stroke?

<p>Abstract</p> <p>Background</p> <p>Elevated serum uric acid (SUA) levels can enhance its antioxidant prosperities and reduce the occurrence of cerebral infarction. Significantly elevated SUA levels have been associated with a better prognosis in patients with cerebral infarction; however, the results from some studies on the relationship between SUA and the prognosis of patients with cerebral infarction remain controversial.</p> <p>Methods</p> <p>We analyzed the relationship between SUA and clinical prognosis of 585 young Chinese adults with acute ischemic stroke as determined by the modified Rankin Scale at discharge. Using multivariate logistic regression modeling, we explore the relationship between SUA levels and patient's clinical prognosis.</p> <p>Results</p> <p>Lower SUA levels at time of admission were observed more frequently in the lowest quintile for patients with severe stroke (P = 0.02). Patients with cerebral infarction patients caused by small-vessel blockage had higher SUA concentrations (P = 0.01) and the lower mRS scores (P < 0.01) were observed in, while the lowest SUA concentrations and the highest mRS scores were seen in patients with cardiogenic cerebral infarction patients. Logistic regression analysis adjusted for confounders confirmed the following independent predictors for young cerebral infarction: uric acid (-0.003: 95%CI 0.994 to 0.999) and platelet (0.004, 95%CI 0.993 to 0.996).</p> <p>Conclusion</p> <p>Elevated SUA is an independent predictor for good clinical outcome of acute cerebral infarction among young adults.</p

The Art of Research: A Divergent/Convergent Framework and Opportunities for Science-Based Approaches

Applying science to the current art of producing engineering and research knowledge has proven difficult, in large part because of its seeming complexity. We posit that the microscopic processes underlying research are not so complex, but instead are iterative and interacting cycles of divergent (generation of ideas) and convergent (testing and selecting of ideas) thinking processes. This reductionist framework coherently organizes a wide range of previously disparate microscopic mechanisms which inhibit these processes. We give examples of such inhibitory mechanisms and discuss how deeper scientific understanding of these mechanisms might lead to dis-inhibitory interventions for individuals, networks and institutional levels

ESR1 gene promoter region methylation in free circulating DNA and its correlation with estrogen receptor protein expression in tumor tissue in breast cancer patients

[Background] Tumor expression of estrogen receptor (ER) is an important marker of prognosis, and is predictive of response to endocrine therapy in breast cancer. Several studies have observed that epigenetic events, such methylation of cytosines and deacetylation of histones, are involved in the complex mechanisms that regulate promoter transcription. However, the exact interplay of these factors in transcription activity is not well understood. In this study, we explored the relationship between ER expression status in tumor tissue samples and the methylation of the 5′ CpG promoter region of the estrogen receptor gene (ESR1) isolated from free circulating DNA (fcDNA) in plasma samples from breast cancer patients. [Methods] Patients (n = 110) with non-metastatic breast cancer had analyses performed of ER expression (luminal phenotype in tumor tissue, by immunohistochemistry method), and the ESR1-DNA methylation status (fcDNA in plasma, by quantitative methylation specific PCR technique). [Results] Our results showed a significant association between presence of methylated ESR1 in patients with breast cancer and ER negative status in the tumor tissue (p = 0.0179). There was a trend towards a higher probability of ESR1-methylation in those phenotypes with poor prognosis i.e. 80% of triple negative patients, 60% of HER2 patients, compared to 28% and 5.9% of patients with better prognosis such as luminal A and luminal B, respectively. [Conclusion] Silencing, by methylation, of the promoter region of the ESR1 affects the expression of the estrogen receptor protein in tumors of breast cancer patients; high methylation of ESR1-DNA is associated with estrogen receptor negative status which, in turn, may be implicated in the patient’s resistance to hormonal treatment in breast cancer. As such, epigenetic markers in plasma may be of interest as new targets for anticancer therapy, especially with respect to endocrine treatment.The study was funded, in part, by a grant from the Ministerio de Educación y Ciencia (CICYT: SAF 2004–00889)

Post-stroke infection: A systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p><b>s</b>troke is the main cause of disability in high-income countries, and ranks second as a cause of death worldwide. Patients with acute stroke are at risk for infections, but reported post-stroke infection rates vary considerably. We performed a systematic review and meta-analysis to estimate the pooled post-stroke infection rate and its effect on outcome.</p> <p>Methods</p> <p>MEDLINE and EMBASE were searched for studies on post-stroke infection. Cohort studies and randomized clinical trials were included when post-stroke infection rate was reported. Rates of infection were pooled after assessment of heterogeneity. Associations between population- and study characteristics and infection rates were quantified. Finally, we reviewed the association between infection and outcome.</p> <p>Results</p> <p>87 studies were included involving 137817 patients. 8 studies were restricted to patients admitted on the intensive care unit (ICU). There was significant heterogeneity between studies (P < 0.001, I²= 97%). The overall pooled infection rate was 30% (24-36%); rates of pneumonia and urinary tract infection were 10% (95% confidence interval [CI] 9-10%) and 10% (95%CI 9-12%). For ICU studies, these rates were substantially higher with 45% (95% CI 38-52%), 28% (95%CI 18-38%) and 20% (95%CI 0-40%). Rates of pneumonia were higher in studies that specifically evaluated infections and in consecutive studies. Studies including older patients or more females reported higher rates of urinary tract infection. Pneumonia was significantly associated with death (odds ratio 3.62 (95%CI 2.80-4.68).</p> <p>Conclusions</p> <p>Infection complicated acute stroke in 30% of patients. Rates of pneumonia and urinary tract infection after stroke were 10%. Pneumonia was associated with death. Our study stresses the need to prevent infections in patients with stroke.</p

Transcriptional Silencing of the Wnt-Antagonist DKK1 by Promoter Methylation Is Associated with Enhanced Wnt Signaling in Advanced Multiple Myeloma

The Wnt/β-catenin pathway plays a crucial role in the pathogenesis of various human cancers. In multiple myeloma (MM), aberrant auto-and/or paracrine activation of canonical Wnt signaling promotes proliferation and dissemination, while overexpression of the Wnt inhibitor Dickkopf1 (DKK1) by MM cells contributes to osteolytic bone disease by inhibiting osteoblast differentiation. Since DKK1 itself is a target of TCF/β-catenin mediated transcription, these findings suggest that DKK1 is part of a negative feedback loop in MM and may act as a tumor suppressor. In line with this hypothesis, we show here that DKK1 expression is low or undetectable in a subset of patients with advanced MM as well as in MM cell lines. This absence of DKK1 is correlated with enhanced Wnt pathway activation, evidenced by nuclear accumulation of β-catenin, which in turn can be antagonized by restoring DKK1 expression. Analysis of the DKK1 promoter revealed CpG island methylation in several MM cell lines as well as in MM cells from patients with advanced MM. Moreover, demethylation of the DKK1 promoter restores DKK1 expression, which results in inhibition of β-catenin/TCF-mediated gene transcription in MM lines. Taken together, our data identify aberrant methylation of the DKK1 promoter as a cause of DKK1 silencing in advanced stage MM, which may play an important role in the progression of MM by unleashing Wnt signaling