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.

[EX Q]: Context: To determine whether cancer antigen-125 (CA-125) levels are increased in women with endometriosis, especially in those with endometriomas (OMAs), deep infiltrating lesions (DIE), and superficial endometriosis (SUP) compared with controls without endometriosis in a large cohort of operated women.', 'Cross-sectional study (Canadian Task Force classification II-2).', 'Tertiary-care university hospital.', 'Four hundred six women with histologically proven endometriosis and 279 women without endometriosis.', 'Surgical examination of the abdomino-pelvic cavity.', 'Preoperative serum CA-125 antigen levels were evaluated by electrochemoluminescence immunoassay in women with endometriosis and controls. Correlations between serum CA-125 levels and clinical and anatomical characteristics of disease severity were examined. Women with endometriosis displayed higher mean serum CA-125 levels compared with disease-free controls (50.1\xa0±\xa062.4 U/mL vs 22.5\xa0±\xa025.2 U/mL; p\xa0≤\xa0.001). CA-125 levels were significantly increased in women with OMA (60.8\xa0±\xa063.5 U/mL) and DIE (55.2\xa0±\xa068.7 U/mL) compared with women with SUP (23.2\xa0±\xa024.5 U/mL) and controls (22.5\xa0±\xa025.2 U/mL). There was no difference in CA-125 levels between patients with SUP and controls and between patients with OMA and DIE. CA-125 serum levels were correlated with DIE severity: the mean number of DIE lesions and worst DIE lesion.\Question: Is increased serum cancer antigen-125 a marker for severity of deep endometriosis?
[EX A]: Serum CA-125 levels were significantly increased in women with severe forms of endometriosis, OMA, and DIE lesions. In addition, elevated serum Ca-125 levels were associated with more severe and extended DIE lesions. In women with superficial peritoneal lesions, CA-125 levels were not different from women without endometriosis.

[EX Q]: Context: Infection of human immunodeficiency virus (HIV) has been associated with several chronic diseases, including pulmonary artery hypertension and atherosclerosis. However, the underlying mechanisms of these vascular complications are largely unknown. The objective of this study was to test a novel hypothesis that HIV Nef, an accessory HIV protein, may directly affect endothelial functions and gene expression in pulmonary arteries.', 'Fresh porcine pulmonary artery rings and human pulmonary artery endothelial cells (HPAECs) were treated with HIV Nef for 24 h. With a myograph device, vasomotor function was determined with thromboxane A2 analog, U46619, for contraction, bradykinin, and sodium nitroprusside for relaxation. The expression of endothelial nitric oxide synthase (eNOS) was determined with real-time PCR and immunohistochemistry. Nitric oxide (NO) production was determined by Calorimetric Nitric Oxide Assay kit. Superoxide anion levels were detected with lucigenin-enhanced chemiluminescence assay and dihydroethidium (DHE) staining.', 'The endothelium-dependent vasorelaxation in response to bradykinin was significantly reduced in HIV Nef-treated porcine pulmonary artery rings in a concentration-dependent manner. In response to bradykinin (10(-8) mol/L), HIV Nef (10 ng/mL) significantly reduced vasorelaxation by 32% compared with untreated controls (P < 0.05). In addition, HIV Nef significantly decreased eNOS expression in the vessels and HPAECs. HIV Nef at 10 ng/mL significantly decreased NO production in HPAECs by 21% compared with controls (P < 0.05). Furthermore, HIV Nef significantly increased superoxide anion production in porcine pulmonary arteries and HPAECs compared with controls (P < 0.05). Consequently, Mn (III) tetrakis porphyrin, a superoxide dismutase mimic, effectively blocked HIV Nef-induced vasomotor dysfunction and superoxide anion production. The specificity of HIV Nef action was confirmed by anti-Nef antibody blocking and Nef heat inactivation.\Question: Does hIV Nef protein cause endothelial dysfunction in porcine pulmonary arteries and human pulmonary artery endothelial cells?
[EX A]: HIV Nef protein significantly decreases endothelium-dependent vasorelaxation in porcine pulmonary arteries. It also reduces eNOS expression and induces oxidative stress in both porcine pulmonary arteries and HPAECs. This study demonstrates a new mechanism of HIV Nef, which causes endothelial dysfunction and may contribute to the human pulmonary artery disease in HIV-infected patients.

[EX Q]: Context: 5-hydroxytryptamine-3 (5-HT3) receptor antagonists inhibit gastric phase-3 motor activity in the dog. This study examined the role of 5-HT3 receptors in the generation of gastric phase 3 of the migrating motor complex in humans.', 'Interdigestive motor activity was recorded manometrically in 16 subjects before and after administration of ondansetron, a selective 5-HT3 receptor antagonist. Plasma motilin values were also assayed in 7 individuals. The incidence of gastric activity fronts before and after ondansetron was compared with a control group that had not received ondansetron. The ability of erythromycin to induce a gastric activity front in the presence of ondansetron was also evaluated in 7 subjects.', 'The incidence of gastric activity fronts was 69% before ondansetron vs. 19% after ondansetron. In contrast, in the control group there was no significant change in the incidence of gastric activity fronts over time. Activity fronts preceding ondansetron were associated with motilin peaks while activity fronts after ondansetron were not. Despite the previous administration of ondansetron, erythromycin induced gastric activity fronts in 89% of cases.\Question: Are 5-hydroxytryptamine-3 receptors involved in the initiation of gastric phase-3 motor activity in humans?
[EX A]:
Selective antagonism of 5-HT3 receptors suppresses the gastric component of phase-3 motor activity and simultaneously suppresses plasma motilin peaks. The results suggest that the suppression of gastric activity fronts is achieved via the suppression of plasma motilin peaks because in the presence of ondansetron a motilin agonist like erythromycin restores the gastric phase 3.