TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: The population analysis of cardiovascular risk and non-risk genetic variation can help to identify adaptive or random demographic processes that shaped coronary incidence variation across geography.', 'In this study, 114 single nucleotide polymorphisms and 17 tandem repeat polymorphisms from Nitric Oxide Synthases (NOS) regions were analyzed in 1686 individuals from 35 populations from Europe, North Africa, and the Middle East. NOS genes encode for key enzymes on nitric oxide availability, which is involved in several cardiovascular processes. These genetic variations were used to test for selection and to infer the population structure of NOS regions. Moreover, we tested whether the variation in the incidence of coronary events and in the levels of classical risk factors in 11 of these European populations could be explained by the population structure estimates.', 'Our results supported, first, the absence of clear signs of selection for NOS genetic variants associated with cardiovascular diseases, and second, the presence of a continuous genetic pattern of variation across European and North African populations without a Mediterranean barrier for gene flow. Finally, population structure estimates from NOS regions are closely correlated with coronary event rates and classical risk parameters (explaining 39-98%) among European populations.\Question: Does population structure from NOS genes correlate with geographical differences in coronary incidence across Europe?

SOLUTION: Our results reinforce the hypothesis that genetic bases of cardiovascular diseases and associated complex phenotypes could be geographically shaped by random demographic processes.

PROBLEM: Context: Benign esophageal strictures are frequently encountered pathologies occurring due to various reasons. Repeated dilatations may be needed, particularly in resistant strictures. This study aimed to evaluate patients who underwent repeated dilatations in our clinic due to resistant esophageal strictures.', 'Sixteen patients who underwent multiple dilatations in our clinic with the diagnosis of resistant benign esophageal stricture between 2007 and 2014 were studied for age, sex, etiology, symptoms, complications, number of dilatations, and intervals between dilatations. Under general anesthesia, all patients underwent dilatation with Savary-Gilliard bougie dilators with the help of rigid esophagoscopy.', 'In 10 of the patients, stenosis was cervical, and in others it was in the thoracic esophagus. The mean dilatation performance was 4.4 (range: 3-12). In 9 patients, dilatations were performed when the patients presented with the complaint of dysphagia. Following the initial dilatation performed for dysphagia, 7 patients underwent endoscopy and dilatation 3-5 times with 1-week intervals without waiting for the development of dysphagia symptoms. These patients developed no complications, and no stenting was needed. In 5 patients, restenosis developed despite multiple dilatations, and esophageal stent placement was performed.\Question: Is recurrent dilatation in resistant benign esophageal strictures : timing significant?

SOLUTION: Dilatations performed at frequent intervals without waiting for the symptoms of dysphagia can contribute to safer and more effective results in resistant benign esophageal strictures.

PROBLEM: Context: Despite CDC recommendations to vaccinate injection drug users (IDUs) against hepatitis A virus (HAV) and hepatitis B virus (HBV) infections, coverage remains low. Vaccination programs convenient to IDUs have not been widely implemented or evaluated. We assessed whether convenience and monetary incentives influenced uptake of free vaccine by 18-30-year-old IDUs in five U.S. cities.', 'IDUs recruited from community settings completed risk behavior self-interviews and testing for antibodies to HAV (anti-HAV) and hepatitis B core antigen (anti-HBc). Vaccine was offered presumptively at pre-test (except in Chicago); on-site availability and incentives for vaccination differed by site, creating a quasi-experimental design.', 'Of 3181 participants, anti-HAV and anti-HBc seroprevalence was 19% and 23%, respectively. Although 83% of participants were willing to be vaccinated, only 36% received > or =1 dose, which varied by site: Baltimore (83%), Seattle (33%), Los Angeles (18%), New York (17%), and Chicago (2%). Participation was highest when vaccine was available immediately on-site and lowest when offered only after receiving results. Monetary incentives may have increased participation when on-site vaccination was not available.\Question: Is convenience the key to hepatitis A and B vaccination uptake among young adult injection drug users?

SOLUTION:
IDUs were willing to be vaccinated but immediate, on-site availability was critical for uptake. Convenience should be a key consideration in designing strategies to increase vaccine coverage among IDUs.