Self-reported race/ethnicity in the age of genomic research: its potential impact on understanding health disparities

This review explores the limitations of self-reported race, ethnicity, and genetic ancestry in biomedical research. Various terminologies are used to classify human differences in genomic research including race, ethnicity, and ancestry. Although race and ethnicity are related, race refers to a person’s physical appearance, such as skin color and eye color. Ethnicity, on the other hand, refers to communality in cultural heritage, language, social practice, traditions, and geopolitical factors. Genetic ancestry inferred using ancestry informative markers (AIMs) is based on genetic/genomic data. Phenotype-based race/ethnicity information and data computed using AIMs often disagree. For example, self-reporting African Americans can have drastically different levels of African or European ancestry. Genetic analysis of individual ancestry shows that some self-identified African Americans have up to 99% of European ancestry, whereas some self-identified European Americans have substantial admixture from African ancestry. Similarly, African ancestry in the Latino population varies between 3% in Mexican Americans to 16% in Puerto Ricans. The implication of this is that, in African American or Latino populations, self-reported ancestry may not be as accurate as direct assessment of individual genomic information in predicting treatment outcomes. To better understand human genetic variation in the context of health disparities, we suggest using “ancestry” (or biogeographical ancestry) to describe actual genetic variation, “race” to describe health disparity in societies characterized by racial categories, and “ethnicity” to describe traditions, lifestyle, diet, and values. We also suggest using ancestry informative markers for precise characterization of individuals’ biological ancestry. Understanding the sources of human genetic variation and the causes of health disparities could lead to interventions that would improve the health of all individuals

HPLC detection of haemoglobinopaties

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Inhibitory effect of asymmetric dimethylarginine and NG-Monomethyl-L-arginine methyl ester on nitric oxide synthase activity

Background and Objective: Nitric oxide synthase (NOS) paly a role in nitric oxide (NO) generation. Despite the beneficial effects of NO on different body systems its overproduction of produce reactive nitrogen species (RNS) and nitrosilation of proteins. This study was done to evaluate the effect of asymmetric dimethylarginine (ADMA) and NG-Monomethyl-L-arginine methyl ester (L-NMMA) on inhibition of nitric oxide synthase activity. Materials and Methods: In this laboratory study, Nitric oxide synthase was extracted from 500 grams of sheep kidney by homogenization, ammonium sulphate precipitation and column chromatography on DEAE-32 Cellulose and 2', 5'-ADP-agarose. During purification, protein content was measured according to the Bradford and enzyme activity was assayed using the Griess reactions the inhibitory effects of 25 μΜ concentrations of ADMA and L-NMMA on purified enzyme were determined. Results: Specific activity and yield of NOS were 0.6 units/mg protein and 0.9%, respectively. Molecular weight of purified enzyme was 54 KD with SDS-PAGE. ADMA and L-NMMA in 25 μΜ concentrations reduced enzyme activity by 76 and 61.2%, respectively. Km values for NOS in absence and in presence of ADMA and L-NMMA were 5.32 μM, 31.25 μM (P<0.05) and 14.29 μM (P<0.05), respectively. Vmax for NOS in absence and presence of inhibitors was not changed. Conclusion: ADMA and L-NMMA have competitive inhibitory effect on NOS activity and ADMA have higher inhibitory effect than L-NMMA

EUS-Guided Gallbladder Drainage

High-risk non-surgical candidates with acute cholecystitis are traditionally treated with the placement of a percutaneous cholecystostomy tube. However, in recent years, transmural gallbladder drainage via an endoscopic ultrasound-guided approach (EUS-GBD) has emerged as a feasible and potential equally efficacious option that obviates the need for an external drainage catheter. Among expert endoscopists, technical and clinical success rates for EUS-GBD are greater than 90% with similar adverse event rates to percutaneous drainage. Early adopters of EUS-GBD used plastic or fully covered metal self-expandable metal biliary stents (FCSEMS), but more recently, the use of a lumen-apposing metal stent (LAMS) has become widespread due to ease of deployment and lower concern for biliary leakage. Furthermore, LAMS provides continued access to the gallbladder for cholecystoscopy or other advanced interventions such as stone removal. Nevertheless, EUS-GBD remains a relatively new procedure and optimal techniques and best practices are still being defined. As such, endoscopists have yet to reach consensus on issues such as optimal location of drainage (transgastric vs. transduodenal), ideal duration for stents to be left in, and whether patients should receive routine cholecystectomy after resolution of symptoms. Until prospective trials address these issues, EUS-GBD should only be reserved for carefully selected patients in tertiary care centers