Predictors of self-expanding metallic stent dysfunction in malignant gastric outlet obstruction. / Predictores de disfunción del stent metálico autoexplandible en la obstrucción de salida gástrica maligna.

INTRODUCTION AND OBJECTIVES: Self-expanding metallic stents (SEMS) are the ideal treatment for malignant gastric outlet obstruction (MGOO) in patients with a short life expectancy, but stent dysfunction is frequent. The primary aim of our study was to identify the predictive factors of SEMS dysfunction in MGOO and the secondary aim was to determine the technical success, clinical success, and nutritional impact after SEMS placement. MATERIAL AND METHODS: A retrospective, longitudinal study was conducted at the gastrointestinal endoscopy department of the Instituto Nacional de Cancerología in Mexico City. Patients diagnosed with MGOO that underwent SEMS placement within the time frame of January 2015 to May 2018 were included. We utilized the gastric outlet obstruction scoring system (GOOSS) to determine clinical success and SEMS dysfunction. RESULTS: The study included 43 patients, technical success was 97.7% (n=42), and clinical success was 88.3% (n=38). SEMS dysfunction presented in 30.2% (n=13) of the patients, occurring in<6 months after placement in 53.8% (n=7) of them. In the univariate analysis, the histologic subtype, diffuse gastric adenocarcinoma (p=0.02) and the use of uncovered SEMS (p=0.02) were the variables associated with dysfunction. Albumin levels and body mass index did not increase after SEMS placement. Medical follow-up was a mean 5.8 months (1-24 months). CONCLUSIONS: SEMS demonstrated adequate technical and clinical efficacy in the treatment of MGOO. SEMS dysfunction was frequent and diffuse type gastric cancer and uncovered SEMS appeared to be dysfunction predictors.

Effect of bovine sperm chromatin integrity evaluated using three different methods on in vitro fertility.

In vitro fertility potential of individual bulls is still relatively uncharacterized. Classical sperm analysis does not include the evaluation of all sperm characteristics and thus, some cell compartments could be neglected. In humans, sperm DNA integrity has already proven to have major influence in embryo development and assisted reproduction techniques successfully. In bovine, some studies already correlated chromatin integrity with field fertility. However, none of those have attempted to relate DNA assessment approaches such as chromatin deficiency (CMA3), chromatin stability (SCSA; AO+) and DNA fragmentation (COMET assay) to predict in vitro bull fertility. To this purpose, we selected bulls with high and low in vitro fertility (n = 6/group), based on embryo development rate (blastocyst/cleavage rate). We then performed CMA3, SCSA test and COMET assay to verify if the difference of in vitro fertility may be related to DNA alterations evaluated by these assays. For the three tests performed, our results showed only differences in the percentage of cells with chromatin deficiency (CMA3+; high: 0.19 ± 0.03 vs low: 0.04 ± 0.04; p = 0.03). No difference for chromatin stability and any of COMET assay categories (grade I to grade IV) was observed between high and low in vitro fertility bulls. A positive correlation between AO + cells and grade IV cells was found. Despite the difference between groups in CMA3 analysis, our results suggest that protamine deficiency in bovine spermatozoa may not have a strong biological impact to explain the difference of in vitro fertility between the bulls used in this study.

Albendazole as a promising molecule for tumor control.

This work evaluated the antitumor effects of albendazole (ABZ) and its relationship with modulation of oxidative stress and induction of DNA damage. The present results showed that ABZ causes oxidative cleavage on calf-thymus DNA suggesting that this compound can break DNA. ABZ treatment decreased MCF-7 cell viability (EC50=44.9 for 24h) and inhibited MCF-7 colony formation (~67.5% at 5µM). Intracellular ROS levels increased with ABZ treatment (~123%). The antioxidant NAC is able to revert the cytotoxic effects, ROS generation and loss of mitochondrial membrane potential of MCF-7 cells treated with ABZ. Ehrlich carcinoma growth was inhibited (~32%) and survival time was elongated (~50%) in animals treated with ABZ. Oxidative biomarkers (TBARS and protein carbonyl levels) and activity of antioxidant enzymes (CAT, SOD and GR) increased, and reduced glutathione (GSH) was depleted in animals treated with ABZ, indicating an oxidative stress condition, leading to a DNA damage causing phosphorylation of histone H2A variant, H2AX, and triggering apoptosis signaling, which was confirmed by increasing Bax/Bcl-xL rate, p53 and Bax expression. We propose that ABZ induces oxidative stress promoting DNA fragmentation and triggering apoptosis and inducing cell death, making this drug a promising leader molecule for development of new antitumor drugs.

Sperm cryodamage occurs after rapid freezing phase: flow cytometry approach and antioxidant enzymes activity at different stages of cryopreservation.

BACKGROUND: In order to improve the efficiency of bovine sperm cryopreservation process, it is important to understand how spermatozoa respond to differences in temperature as well as the ability to recover its own metabolism. The combination between flow cytometry approach and antioxidant enzymes activity allows a more sensible evaluation of sperm cell during cryopreservation. The aim of this study was to evaluate sperm attributes and antioxidant enzymes activity during different stages of cryopreservation process. Semen samples from Holstein bulls (n = 4) were separated in 3 treatments: fresh (37 °C); cooled (5 °C); and thawed. Evaluation occurred at 0 h and 2 h after incubation. Membrane integrity, mitochondrial membrane potential (MMP) and DNA damages were evaluated by flow cytometry; activities of antioxidant enzymes such as catalase, superoxide dismutase and gluthatione peroxidase were measured by spectrofotometry. RESULTS: There was an increase in the percentage of sperm with DNA damage in the thawed group, compared to fresh and cooled, and for 2 hs of incubation when compared to 0 h. Considering MMP, there was an increase in the percentage of cells with medium potential in thawed group when compared to fresh and cooled groups. Opposingly, a decrease was observed in the thawed group considering high mitochondrial potential. Also in the thawed group, there was an increase on cells with damaged acrosome and membrane when compared to fresh and cooled groups. Significant correlations were found between antioxidant enzymes activity and membrane or mitochondrial parameters. CONCLUSION: Based on our results, we conclude that cryopreservation affects cellular and DNA integrity and that the critical moment is when sperm cells are exposed to freezing temperature. Also, our study indicates that intracellular antioxidant machinery (SOD and GPX enzymes) is not enough to control cryodamage.

Genotoxicity testing of Ambelania occidentalis (Apocynaceae) leaf extract in vivo.

Ambelania occidentalis is routinely used in folk medicine for treating gastrointestinal disorders, even though there have been no safety trials. We evaluated the genotoxic potential of hydro-alcoholic extracts of this plant in mice; induced DNA damage was assessed in peripheral blood leukocytes and micronucleus induction was assessed in polychromatic erythrocytes from bone marrow. The extract was administered by an oral route at single doses of 1000, 1500 and 2000 mg/kg body weight. N-nitroso-N-ethylurea was used as a positive control. The comet assay was performed on peripheral blood leukocytes at 4 and 24 h after treatment, and the micronucleus test was carried out on bone marrow cells collected at 24 and 48 h after treatment. The ratio of polychromatic/normochromatic erythrocytes was scored for cytotoxicity assessment. No increase in the number of micronucleated polychromatic erythrocytes from bone marrow or in leukocyte DNA damage was observed. The hydro-alcoholic extracts of A. occidentalis had no mutagenic or cytotoxic effects in the mouse cells.

Effect of smoking habits on sleep.

To evaluate the effect of smoking habits on sleep, data from 1492 adults referred to the Sleep Institute were accessed and divided into 3 categories of smoking status: current, former and non-smokers. Categories of pack-years (<15 and > or =15) defined smoking severity. The association of smoking status and smoking severity with sleep was analyzed for sleep parameters, especially apnea and hypopnea index (AHI) > or =5, more than 5% of total sleep time (TST) spent with oxyhemoglobin saturation (SaO2) <90%, and arousal index. The arousal index was higher among current (21 +/- 17) and former smokers (20 +/- 17) than non-smokers (17 +/- 15; P < 0.04). Former smokers had a higher percent of TST at SaO2 <90% than non-smokers (9 +/- 18 vs 6 +/- 13; P < 0.04). Former smokers with pack-years > or =15 compared to <15 exhibited higher AHI (22 +/- 24 vs 16 +/- 21; P < 0.05) and arousal index (22 +/- 19 vs 18 +/- 15; P < 0.05). Current smokers with pack-years > or =15 compared to <15 exhibited higher arousal index (23 +/- 18 vs 18 +/- 16; P < 0.05) and percent of TST at SaO2 <90% (11 +/- 17 vs 6 +/- 13; P < 0.05). Smoking status and pack-years were not associated with AHI > or =5 on logistic regression analysis, but current smokers with pack-years > or =15 were 1.9 times more likely to spend more than 5% of TST at SaO2 <90% than non-smokers (95%CI = 1.21-2.97; P = 0.005). The variability of arousal index was influenced by gender, AHI and current smokers with pack-years > or =15 (all P < 0.01). Smoking habits seem to be associated with arousal and oxyhemoglobin desaturation during sleep, but not with AHI. The effect was more pronounced in current than former smokers.

Effect of smoking habits on sleep

To evaluate the effect of smoking habits on sleep, data from 1492 adults referred to the Sleep Institute were accessed and divided into 3 categories of smoking status: current, former and non-smokers. Categories of pack-years (<15 and greater than or equal to 15) defined smoking severity. The association of smoking status and smoking severity with sleep was analyzed for sleep parameters, especially apnea and hypopnea index (AHI) greater than or equal to 5, more than 5 percent of total sleep time (TST) spent with oxyhemoglobin saturation (SaO2) <90 percent, and arousal index. The arousal index was higher among current (21 plus or minus 17) and former smokers (20 plus or minus 17) than non-smokers (17 plus or minus 15; P < 0.04). Former smokers had a higher percent of TST at SaO2 <90 percent than non-smokers (9 more less 18 vs 6 more less 13; P < 0.04). Former smokers with pack-years greater than or equal to 15 compared to <15 exhibited higher AHI (22 plus or minus 24 vs 16 plus or minus 21; P < 0.05) and arousal index (22 plus or minus 19 vs 18 plus or minus 15; P < 0.05). Current smokers with pack-years greater than or equal to 15 compared to <15 exhibited higher arousal index (23 plus or minus 18 vs 18 plus or minus 16; P < 0.05) and percent of TST at SaO2 <90 percent (11 plus or minus 17 vs 6 more less 13; P < 0.05). Smoking status and pack-years were not associated with AHI greater than or equal to 5 on logistic regression analysis, but current smokers with pack-years greater than or equal to 15 were 1.9 times more likely to spend more than 5 percent of TST at SaO2 <90 percent than non-smokers (95 percentCI = 1.21-2.97; P = 0.005). The variability of arousal index was influenced by gender, AHI and current smokers with pack-years greater than or equal to 15 (all P < 0.01). Smoking habits seem to be associated with arousal and oxyhemoglobin desaturation during sleep, but not with AHI. The effect was more pronounced in current than former smokers.

A framework for automated evidence gathering with mobile systems using Bayesian Networks.

This article presents a framework that allows the automated gathering of medical evidence, using a methodology based on Bayesian Networks (BN). For such purpose, system software and a programming methodology were developed. The proposed methodology is generic and can be applied to different contexts (application domains) were evidence gathering is executed in mobile devices.

Telomerase activity in pulmonary neuroendocrine tumors: correlation with histologic subtype (MS-0060).

The authors measured telomerase activity using the telomeric repeat amplification protocol-enzyme-linked immunosorbent assay method in 13 neuroendocrine pulmonary neoplasms and in non-neoplastic frozen lung samples from the same patients. These cases belonged to the complete neuroendocrine neoplastic spectrum: four typical carcinoids, three atypical carcinoids, four large cell neuroendocrine lung carcinomas, and two small cell lung carcinomas. The authors performed the same assay for 52 non-neoplastic lung tissues from the surgical files in their department (negative controls). They verified the presence (or absence) of neoplastic tissue in every case by looking at one frozen section done in the same tissue used for telomerase assay. The telomerase activity level in non-neoplastic tissues (mean, 182 A450nm U) was similar to that obtained in the typical carcinoids (mean, 104.5 A450nm U). All neuroendocrine tumors but the typical carcinoids showed high levels of telomerase activity (mean, 1,750.8 A450nm U). According to the telomerase hypothesis, typical carcinoid cells are mortal pre-M2 stage cells, but atypical carcinoid, large cell neuroendocrine lung carcinoma, and small cell lung carcinoma cells are immortal post-M2 stage cells. This finding may be of important prognostic significance in these kinds of tumors. Measurement of enzyme activity with a good morphologic control could be necessary in telomerase activity assay.

Transjugular intrahepatic portosystemic shunt with the Strecker stent for control of refractory acute and chronic variceal bleeding.

BACKGROUND: We wanted to assess prospectively the safety, efficacy, and applicability of transjugular intrahepatic portosystemic shunt (TIPS) with the Strecker stent, focusing mainly on clinical and hemodynamic medium- and long-term follow-up. METHODS: Fifty-two patients reached an indication to perform a TIPS, in an emergency or after refractory variceal bleeding. It was completed in 50 of them. All presented with cirrhosis (Child C = 15, B = 23, A = 12). The prosthesis was a Strecker stent. During the follow-up, clinical, biochemical, endoscopic, ultrasound, and pressure measurement studies were performed at 1, 3, 6, 12 months. Mean follow-up was 13.5 + or - 7.8 months. RESULTS: Portal pressure decreased from 32.3 + or - 8.1 (mean + or - standard deviation) to 22.3 + or - 6.7 mm Hg and portocaval gradient from 21 +/- 5.2 to 8.7 +/- 3.9 mm Hg (average, 56 + or - 16%). Shunt dysfunction was diagnosed when the portocaval gradient was >12 mm Hg (20 patients). Eleven patients (22%) presented with variceal rebleeding because of shunt dysfunction. The probability of remaining free of bleeding was 78%, 74%, and 68% at 6, 12, and 24 months, respectively. Actuarial survival rate was 91% and 86% after 12 and 18 months, respectively. CONCLUSION: TIPS with the Strecker stent is a safe alternative for variceal bleeding. Shunt dysfunction is frequent and increases the rebleeding rate, requiring a close follow-up with pressure measurements. Randomized trials comparing stents and other alternatives are needed to fully address the role of this procedure.