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: To survive and reproduce, animals must be able to modify their motor behavior in response to changes in the environment. We studied a complex behavior of Caenorhabditis elegans, male mating behavior, which provided a model for understanding motor behaviors at the genetic, molecular as well as circuit level. C. elegans male mating behavior consists of a series of six sub-steps: response to contact, backing, turning, vulva location, spicule insertion, and sperm transfer. The male tail contains most of the sensory structures required for mating, in addition to the copulatory structures, and thus to carry out the steps of mating behavior, the male must keep his tail in contact with the hermaphrodite. However, because the hermaphrodite does not play an active role in mating and continues moving, the male must modify his tail posture to maintain contact. We provide a better understanding of the molecular and neuro-muscular pathways that regulate male tail posture during mating.', 'Genetic and laser ablation analysis, in conjunction with behavioral assays were used to determine neurotransmitters, receptors, neurons and muscles required for the regulation of male tail posture. We showed that proper male tail posture is maintained by the coordinated activity of opposing muscle groups that curl the tail ventrally and dorsally. Specifically, acetylcholine regulates both ventral and dorsal curling of the male tail, partially through anthelmintic levamisole-sensitive, nicotinic receptor subunits. Male-specific muscles are required for acetylcholine-driven ventral curling of the male tail but dorsal curling requires the dorsal body wall muscles shared by males and hermaphrodites. Gamma-aminobutyric acid activity is required for both dorsal and ventral acetylcholine-induced curling of the male tail and an inhibitory gamma-aminobutyric acid receptor, UNC-49, prevents over-curling of the male tail during mating, suggesting that cross-inhibition of muscle groups helps maintain proper tail posture.
Answer: Our results demonstrated that coordination of opposing sex-specific and core muscle groups, through the activity of multiple neurotransmitters, is required for regulation of male tail posture during mating. We have provided a simple model for regulation of male tail posture that provides a foundation for studies of how genes, molecular pathways, and neural circuits contribute to sensory regulation of this motor behavior.

SOLUTION: Does coordination of opposing sex-specific and core muscle groups regulate male tail posture during Caenorhabditis elegans male mating behavior?

PROBLEM: Context: Parkinsonian signs, especially gait impairment, are common and associated with morbidity and mortality in older persons. Our objective was to test the hypothesis that substantia nigra neurofibrillary tangles (NFTs) are related to parkinsonian signs in older persons with and without dementia.', "We studied 86 deceased older Catholic clergy without idiopathic Parkinson's disease from the Religious Order Study, a longitudinal clinical-pathological study. Mean age at death was 85.3 years. Signs of gait disturbance, bradykinesia, rigidity, and tremor were assessed proximate to death using a modified Unified Parkinson's Disease Rating Scale. Forty-micrometer paraffin-embedded sections of substantia nigra were bleached before tau immunohistochemistry and the optical disector was used to count NFTs. We used multivariable linear regression to examine parkinsonian signs as a function of nigra NFTs, controlling for age, sex, education, and cortical NFTs.", 'Substantia nigra NFTs were present in 67 of 86 persons (77.9%). After controlling for age, sex, education, and cortical NFTs, nigra NFTs were related to gait impairment (p < 0.001), but not bradykinesia, rigidity, or tremor. Results were not confounded by dementia, Braak score, neuroleptic medication, cerebral infarcts, or Lewy bodies.
Answer: NFTs in the substantia nigra are associated with gait impairment in older persons with and without dementia.

SOLUTION: Are substantia nigra tangles related to gait impairment in older persons?

PROBLEM: Context: Angiopoietin-like protein 3, a liver-derived plasma protein, increases plasma triglycerides (TG) in mice by suppressing the activity of lipoprotein lipase, a key enzyme in plasma TG clearance. Uremic dyslipidemia is characterized by increased TG-rich lipoproteins such as very low-density lipoprotein (VLDL) and intermediate-density lipoprotein (IDL), lowered high-density lipoprotein (HDL), and TG-enrichment of low-density lipoprotein (LDL) and HDL. Since the role of angiopoietin-like protein 3 (ANGPTL3) in uremic dyslipidemia is unknown, we examined its possible association with the lipoprotein abnormalities in patients with chronic renal failure (CRF).', 'The subjects were 202 hemodialysis patients, 44 predialysis patients with CRF and 148 healthy control subjects comparable in age and sex. Fasting plasma ANGPTL3 was measured by enzyme-linked immunoassay, and lipoproteins were fractioned by ultracentrifugation.', 'Median (25th-75th percentile range) ANGPTL3 levels were 523 (409-645) and 393 (308-511)ng/mL in hemodialysis and predialysis patients, respectively, which were significantly lower than the control level of 700 (570-875)ng/mL. In the total subjects, ANGPTL3 was inversely correlated with VLDL- and IDL-cholesterol levels, and positively with HDL-cholesterol. ANGPTL3 correlated inversely with TG/cholesterol ratios of both LDL and HDL. In multiple regression models, these associations, excluding TG/cholesterol ratio of LDL, remained significant and independent of possible confounders including age, sex, body mass index, insulin resistance index (HOMA-IR), and adiponectin, whereas the associations of ANGPTL3 with the lipoprotein parameters were less significant when apoC-II/C-III ratio was included in the models.
Answer: The reduced ANGPTL3 level in hemodialysis patients was consistently associated with the major components of uremic dyslipidemia. ANGPTL3 may be a novel factor contributing to uremic dyslipidemia.

SOLUTION:
Is plasma angiopoietin-like protein 3 ( ANGPTL3 ) concentration associated with uremic dyslipidemia?