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.

[Q]: 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.
[A]: Does deletion of TRPC4 and TRPC6 in mice impair smooth muscle contraction and intestinal motility in vivo?


[Q]: Context: Visceral obesity is shown to be a predictor of morbidity and mortality. We evaluated the association of measurements of generalized adiposity and visceral fat area (VFA), with abnormalities of metabolic syndrome (MS).', 'Seventy-six women (47.9 +/- 9.2 years) with BMI of 38.7 +/- 5.4 kg/m(2) underwent anthropometric measurements, laboratory procedures, bioeletrical impedance, and abdominal computed tomography (CT) scan. Diagnosis of MS was based on the presence of abdominal obesity and at least two of the following components: hypertension, dyslipidemia, and glucose intolerance and/or hyperinsulinemia.', 'BMI was correlated with both components of adipose tissue--subcutaneous (r = 0.66, P < 0.01) and VFA (r = 0.33, P < 0.02)--and leptin levels (r = 0.38, P < 0.01). In contrast, VFA was correlated with 2-h glucose and insulin levels (r = 0.32 and 0.35, P < 0.05, respectively), triglyceride, HDL cholesterol, and uric acid (r = 0.33, -0.34 and 0.24, P < 0.05, respectively). Subjects with high VFA, matched for BMI, showed greater plasma glucose area under the curve (621 +/- 127 vs. 558 +/- 129 mg x h(-1) x dl(-1), P < 0.05), 2-h insulin (804 +/- 599 vs. 579 +/- 347 pmol/l, P < 0.05), and uric acid levels (0.33 +/- 0.07 vs. 0.26 +/- 0.06 mmol/l, P < 0.05) than subjects with low VFA. In logistic regression analysis, waist circumference, VFA, and 2-h insulin were identified as independent predictors of MS. Receiver operating characteristic curve analysis pointed out the values of 104 cm for waist circumference (58.1% specificity, 84.1% sensitivity), 158.5 cm(2) for VFA (78.1% specificity, 52.3% sensitivity), and 559.8 pmol/l for 2-h insulin (71.9% specificity, 69.8% sensitivity); the presence of at least two of the three variables resulted in a degree of concordance of 76%.
Answer: While BMI was unable to differentiate between obese people and those at higher risk for MS, abdominal fat was shown to be associated with its metabolic abnormalities. The usefulness of abdominal fat in the identification of high-risk subjects may be improved when combined with 2-h insulin determination.
[A]: Does two-hour insulin determination improve the ability of abdominal fat measurement to identify risk for the metabolic syndrome?


[Q]: Context: Elevated myeloperoxidase (MPO) levels are predictive of high cardiovascular (CV) risk in the general population. The value of MPO as a CV marker in the HIV population has not been investigated.', 'Medical records were reviewed to identify HIV+ patients with a documented CV event (myocardial ischemia/infarction) and stored plasma samples within 12 months prior to the event. HIV+ adults with no CV history and with similarly available stored plasma samples were site-, age-, and gender-matched 1:1 to cases.', 'We identified 124 participants (62 case-control pairs): 94% male, median age 46 years. Median (IQR) MPO levels (pmoles/L) were lower in cases vs. controls: 292 (235-376) vs. 320 (249-467); p= .004. Cases were more likely to have other CV risk factors, including smoking, hypertension, and higher cholesterol and triglycerides. The observed MPO directional difference persisted after controlling for CV risk factors. In the reduced model, observed differences in MPO remained independently and negatively associated with CV event (p= .03) after adjusting for two positively associated risk factors, differences in cholesterol levels (p= .01), and differences in smoking history (ever smoked vs. never smoked; p= .04). Differences in triglyceride levels and hypertension were not statistically significant independent risk factors in this sample (p> .05). Within cases, MPO was negatively correlated with CD4 count (rs= -0. 40, p= .0023) and age (rs= -0. 34, p= .01). In contrast, age at blood draw was positively correlated with MPO in controls (rs= 0.28, p= .031) and CD4 was uncorrelated (rs= -0. 01, p> .9). No other factors were significantly correlated with MPO within groups.
Answer: In contrast to the general population, higher MPO levels were not predictive of CV events in this study, underscoring the fact that pathways operative in HIV arteriopathy may be distinct from traditional CV disease pathogenesis.
[A]:
Are higher plasma myeloperoxidase levels associated with an increased risk for cardiovascular events in HIV-infected adults?