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.

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

Context: Women have poorer outcomes after vascular surgery as compared to men as shown by studies recently. Frailty is also an independent risk factor for postoperative morbidity and mortality. This study examines the interplay of gender and frailty on outcomes after infrainguinal vascular procedures.', 'The American College of Surgeons National Surgical Quality Improvement Program database was used to identify all patients who underwent infrainguinal vascular procedures from 2005-2012. Frailty was measured using a modified frailty index (mFI; derived from the Canadian Study of Health and Aging). Univariate and multivariate analysis were performed to investigate the association of preoperative frailty and gender, on postoperative outcomes.', 'Of 24,645 patients (92% open, 8% endovascular), there were 533 deaths (2.2%) and 6198 (25.1%) major complications within 30 d postoperatively. Women were more frail (mean mFI = 0.269) than men (mean mFI = 0.259; P < 0.001). Women and frail patients (mFI>0.25) were more likely to have a major morbidity (P < 0.001) or mortality (P < 0.001) with the highest risk in frail women. On multivariate logistic regression analysis, female gender and increasing mFI were independently significantly associated with mortality (P < 0.05) as well as major complications. The interaction of gender and frailty in multivariate analysis showed the highest adjusted 30-d mortality and morbidity in frail females at 2.8% and 30.1%, respectively and that was significantly higher (P < 0.001) than nonfrail males, nonfrail females and frail males.
Answer: Female gender and frailty are both associated with increased risk of complications and death following infrainguinal vascular procedures with the highest risk in frail females. Further studies are needed to explore the mechanisms of interaction of gender and frailty and its effect on long-term outcomes for peripheral vascular disease.
Do gender and frailty predict poor outcomes in infrainguinal vascular surgery?

Context: Aberrant expression of the cell cycle kinase inhibitors p16, p21, and p27 has been associated with poor prognosis in a variety of human malignancies. Little is known, however, about their clinical impact in vulvar carcinoma patients. Thus, we analyzed a larger series of vulvar squamous cell carcinomas and compared the results with clinical outcome.', 'A total of 224 vulvar squamous cell carcinomas were immunohistochemically investigated for expression of p16, p21, and p27 using the biotin-streptavidin-peroxidase method and the OptiMax Plus automated cell staining system.', 'High p16 (> or =5%) positive nuclear immunostaining was found in 69 (31%) cases, high p21 (any staining) protein levels was detected in 95 (42%) cases, and low p27 (< or =50% positive nuclei) staining was seen in 170 (76%) cases. High expression of p16 was related to lower patient age and low expression of p53. High expression of p16 indicated a better prognosis in the multivariate analysis (RR = 0.5, 95% CI = 0.2-1.0) and less risk of developing lymph node metastasis (OR = 0.3, 95% CI = 0.2-0.7). High level of p21 was significantly associated with shorter survival in patients staged FIGO I and II (RR = 3.4, 95% CI = 1.3-9.3). We found no significant correlation between the expression of p27 and any of the clinicopathological variables.
Answer: Our study indicates a prognostic relevance for p16 and p21 immunoreactivity. Low level of p16 protein and high level of p21 protein were associated with a shorter disease-related survival. We did not find p27 protein expression to be useful as a prognostic indicator in vulvar carcinoma patients.

Does p16INK4a and p21Waf1/Cip1 expression correlate with clinical outcome in vulvar carcinomas?