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.

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?

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.
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Q: Context: P53 is a key protein which controls cell cycle arrest and apoptosis in response to DNA damage. Auto-antibodies against p53 have been detected in some cancer patients and also in patients with autoimmune diseases. In these patients, the main cause of anti-p53 antibody occurrence was considered to be increased intracellular p53 protein in cancer cells and autoreactive lymphocytes, respectively. Intracellular p53 also increases with cardiomyocyte apoptosis during heart failure and autoreactive lymphocytes play a role in the course of idiopathic dilated cardiomyopathy (IDC) and ischemic cardiomyopathy (ICM). Based on these observations, we hypothesized that anti-p53 antibody response may also occur in patients with heart failure due to ICM and IDC.', 'The aim of this study was to evaluate anti-p53 antibodies in the serum of patients with heart failure due to IDC and ICM.', '70 eligible patients with heart failure and severe left ventricular systolic dysfunction (mean fractional shortening 12.03 +/- 3.93%) were included in the study. The aetiology of heart failure was IDC in 26 patients and ICM in 44 patients, according to the angiographic and echocardiographic findings.', 'Anti-p53 antibodies were not detected in any of the patients.\Question: Do serum anti-p53 antibodies occur in patients with heart failure due to idiopathic dilated and ischemic cardiomyopathies?

A: Anti-p53 antibodies do not occur in patients with heart failure due to IDC and ICM, possible explanations are discussed in the text.
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Q: Context: Multicentric fibroadenomas, defined as multiple fibroadenomas located at different quadrants of the breast, occur in 10-20% of women with fibroadenoma. The surgical management of multicentric fibroadenomas may be troublesome for surgeons and patients. In this study, we report our preliminary experience using the "round block technique" in the management of women with multicentric fibroadenomas of the breast.', "Records of patients with breast diseases managed with the round block technique were searched for in the Changhua Christian Hospital oncoplastic breast surgery database. The patients' clinicopathologic characteristics, type of surgery, operation time, blood loss, and complications were recorded. The cosmetic outcome was evaluated by the patient and operating surgeon two months after the surgery.", 'Twenty patients with multicentric fibroadenomas managed by the round block technique comprised the current study cohort. The mean age of the subjects was 36.510.4 years. Twelve (60%) patients had tumors on one side of the breast, and eight (40%) had bilateral breast lesions. The average number of tumors removed was 3.31.2 (range 2-6) per breast, and mean tumor size was 2.20.5cm. Three (15%) patients developed mild ecchymosis of the breast undergoing operation, which resolved spontaneously. One (5%) patient had partial nipple ischemia/necrosis due to 2 tumors excised near the nipple-areolar complex. The aesthetic results were evaluated as good in 19 (95%) patients and fair in 1 (5%).\Question: Is round block technique a useful oncoplastic procedure for multicentric fibroadenomas?

A:
The round block technique is a useful oncoplastic procedure for the management of multicentric fibroadenomas excised at the same time.
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