TASK DEFINITION: Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
PROBLEM: Context: Downstream effects of muscarinic receptor stimulation in intestinal smooth muscle include contraction and intestinal transit. We thought to determine whether classic transient receptor potential (TRPC) channels integrate the intracellular signaling cascades evoked by the stimulated receptors and thereby contribute to the control of the membrane potential, Ca-influx, and cell responses.', 'We created trpc4-, trpc6-, and trpc4/trpc6-gene-deficient mice and analyzed them for intestinal smooth muscle function in vitro and in vivo.', 'In intestinal smooth muscle cells TRPC4 forms a 55 pS cation channel and underlies more than 80% of the muscarinic receptor-induced cation current (mI(CAT)). The residual mI(CAT) depends on the expression of TRPC6, indicating that TRPC6 and TRPC4 determine mI(CAT) channel activity independent of other channel subunits. In TRPC4-deficient ileal myocytes the carbachol-induced membrane depolarizations are diminished greatly and the atropine-sensitive contraction elicited by acetylcholine release from excitatory motor neurons is reduced greatly. Additional deletion of TRPC6 aggravates these effects. Intestinal transit is slowed down in mice lacking TRPC4 and TRPC6.
Answer: In intestinal smooth muscle cells TRPC4 and TRPC6 channels are gated by muscarinic receptors and are responsible for mI(CAT). They couple muscarinic receptors to depolarization of intestinal smooth muscle cells and voltage-activated Ca(2+)-influx and contraction, and thereby accelerate small intestinal motility in vivo.

SOLUTION: Does deletion of TRPC4 and TRPC6 in mice impair smooth muscle contraction and intestinal motility in vivo?

PROBLEM: Context: Differences in mortality are thought to exist between African Americans and Caucasians with heart failure. These differences may be due to a variety of factors, including differences in disease process, socioeconomic status, and access to health care. Additionally, little data exist on racial differences between these two groups after cardiac transplantation. This study examines a single center, urban experience in treating African Americans and Caucasians with heart failure and after cardiac transplantation. We hypothesize that treatment in a specialized, comprehensive heart failure/cardiac transplantation program results in similar survival between African Americans and Caucasians.', 'We retrospectively reviewed the Rush Heart Failure and Cardiac Transplant Database from July 1994 to August 2000. Variables analyzed in the cardiomyopathy patients included survival (until death, placement of left ventricular assist device or cardiac transplantation), number of hospitalizations per year, length of stay per year, and utilization of outpatient resources. Follow-up period was from initial visit to death, transplantation, or implantation of left ventricular assist device. In those who underwent cardiac transplantation, we examined rejection rates (cellular and humoral), rejection burden, hospitalization data, and 5-year survival. A subgroup bridged to cardiac transplantation with a left ventricular device was also analyzed.', 'Seven hundred thirty-four cardiomyopathy patients were identified: 203 were African Americans and 531 were Caucasians. The etiology of cardiomyopathy was more commonly ischemic in Caucasians as compared to non-ischemic in African Americans (P <.01). African Americans had more admissions to the hospital per year compared with Caucasians, 1.2 +/- 2.1 versus.5 +/- 1.1 (P <.01) with longer length of stay per year, 1.4 +/- 25.2 days versus 4.4 +/- 14.3 days (P <.01). Utilization of outpatient resources was significantly higher in African Americans compared with Caucasians with more use of continuous inotropes (13% versus 6%, P <.01), intermittent inotropes (11% versus 5%, P <.01), and home nursing after hospital discharge (52% versus 32% of hospital discharges, P <.01). Survival by Kaplan-Meier analysis was comparable between the two groups (mean survival 1,470 +/- 72 days in African Americans versus 1521 +/- 46 days in Caucasians, log rank test [P =.6]). During this time, 30 African Americans and 73 Caucasians underwent cardiac transplantation. Fifty-three were bridged to transplantation with a left ventricular assist device (20 African Americans, 33 Caucasians). There were no differences in 5-year survival by Kaplan-Meier analysis despite higher peak preoperative panel reactive antibody levels in African Americans versus Caucasians (12% +/- 30% compared with 5% +/- 15%, P =.04), more overall treated rejection episodes per year in the African Americans (P <.01), as well as more posttransplant hospitalizations (2.2 +/- 1.2 times per year as compared with 1.7 +/- 2.1 times per year, P =.04).
Answer: Delivery of care to heart failure patients in a comprehensive, specialized program results in similar survival regardless of race despite higher utilization of inpatient and outpatient resources. The finding that, after cardiac transplantation, African Americans do not have higher mortality rates, despite having higher rates of rejection overall and more hospitalizations, further supports the hypothesis that optimal care can improve outcomes despite unfavorable baseline clinical characteristics.

SOLUTION: Are influence of race in heart failure and cardiac transplantation : mortality differences eliminated by specialized , comprehensive care?

PROBLEM: Context: The symptoms of sleep apnea, such as sleep fragmentation and oxygen desaturation, might be risk factors for subsequent mood disorder (MD), but associations between sleep apnea and MD remain unclear. This nationwide population-based study thus aimed to identify the risk of MD in patients with vs. without sleep apnea.', 'This cohort study used data from the National Health Insurance database. In total, 5415 patients diagnosed with sleep apnea between 2000 and 2010 were evaluated, and 27,075 matched non-sleep apnea enrollees were included as a comparison cohort. All subjects were followed until 2011. The Cox proportional hazard ratio (HR) was used to investigate the relationship between MD and sleep apnea while controlling covariates and comorbidities of sleep apnea.', 'Of 5415, 154 patients with sleep apnea (2.84\xa0%) were diagnosed with MD during the follow-up period in comparison with 306 of 27,075 individuals (1.13\xa0%) without antecedent sleep apnea. After adjusting for the selected factors and comorbidities, we found that patients with sleep apnea were from 1.82- to 2.07-fold greater risk of MD than the comparisons. Of the three subcategories of MD (major depressive disorder, bipolar disorder, and unspecified MD), sleep apnea had the highest predisposing risk with respect to major depressive disorder (adjusted HR from 1.82 to 2.07) and bipolar disorder (adjusted HR from 2.15 to 3.24).
Answer: There is a greater likelihood of MD manifesting in patients with a history of sleep apnea. Health professionals are thus advised to carefully monitor the psychological impacts of sleep apnea.

SOLUTION:
Is sleep apnea associated with an increased risk of mood disorders : a population-based cohort study?