instruction:
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.
question:
Context: To investigate the role of the anti-cellular immune response in the protection of rhesus macaques against infection with the simian immunodeficiency virus SIVmac. To determine the biological differences between SIV challenge stocks grown either on human T-cell lines or on monkey peripheral blood mononuclear cells (MPBMC).', 'A protective SIVmac split vaccine was administered to rhesus macaques and their anti-, B- and T-cell response monitored. Vaccinees and controls were challenged with SIVmac grown either on human or on monkey cells. The in vivo replication rate of, and the immune response to, the two viruses was compared.', 'Five rhesus macaques were immunized with a total of 2 mg each of purified SIVmac251/32H grown on the human C8166 T-cell line. The antibody and proliferative T-cell responses were evaluated by enzyme-linked immunosorbent assay and T-cell proliferation assay, respectively. Four protected animals and four controls were reboosted and challenged with MPBMC-grown SIVmac251 (SIVmac251/MPBMC). Cell-free virus load was determined by titration of plasma for SIV infectivity on C8166 cells and antigen with a core antigen capture assay.', 'Protection from virus challenge with C8166-grown SIVmac251/32H or SIVmac251/MPBMC did not correlate with anti-cellular antibodies or proliferative T-cell reactivities. Control animals infected with SIVmac251/MPBMC showed high persistent antigenaemia and high plasma virus titres. Both were absent in controls infected with complement C8166-grown SIVmac251/32H. Whereas the latter always seroconverted against the full panel of viral polypeptides, SIVmac251/MPBMC-infected animals showed a drastically decreased antibody response.\Question: Does protection of monkeys by a split vaccine against SIVmac depend upon biological properties of the challenge virus?
answer:
Neither the antibody nor the proliferative T-cell response to SIVmac correlates with protection from virus challenge. In contrast to SIVmac251/32H grown on C8166 cells, the MPBMC-grown challenge virus SIVmac251 appears to belong to the 'rapid-high' phenotype, possibly explaining the lack of protection against this SIV.


question:
Context: The surgical treatment method in which the peritoneal cavity is opened anteriorly and deliberately left open, hence often called "open abdomen" has become the standard of care in damage-control procedures as well as in the management of intra-abdominal hypertension and in severe intra-abdominal sepsis. Whereas open abdomen has been closed in two stages traditionally, a modern trend is to close the fascial layers within the initial hospitalization to avoid complications like enterocutaneous fistula and hernia formation. The aim of this study was to determine crucial factors influencing the possibility of fascial closure after open abdomen.', 'Between 2003 and 2013, 355 adult patients were treated with open abdomen in our institution. Their data were collected and retrospectively analyzed. They were divided into two groups depending on fascial closure or not (fascial closure, n\xa0=\xa0137 (39%) vs. non-fascial closure, n\xa0=\xa0218 (61%)).', 'The patients who reached fascial closure had a significantly higher rate of initially performed open abdomen (97 patients (71%) vs. 118 (54%), p\xa0=\xa00.002) and the periods of time until a second and a third look operation were significantly shorter (2.7\xa0±\xa02.5 vs. 4.2\xa0±\xa06.6 days, p\xa0=\xa00.021 and 5.6\xa0±\xa03.7 vs. 8.5\xa0±\xa08.6 days, p\xa0=\xa00.006). Furthermore, the presence of peritonitis (64 patients (47%) vs. 83 patients (38%), p\xa0=\xa00.023) and large bowel resection (74 patients (54%) vs. 90 patients (41%), p\xa0=\xa00.022) were significantly higher in this group. Rates of in-hospital mortality (97 patients (44%) vs. 38 patients (28%), p\xa0=\xa00.002) and the presence of pancreatitis (19 patients (9%) vs. 3 patients (2%), p\xa0=\xa00.013) were significantly higher in the non-fascial closure group.\Question: Are fascial closure after open abdomen : initial indication and early revisions decisive factors -- a retrospective cohort study?
answer:
The probability to reach fascial closure after open abdomen seems to increase when open abdomen is performed initially and when early second and third look operations are performed. The presence of pancreatitis seems to be the only negative prognostic marker concerning fascial closure.


question:
Context: Crohn's disease is associated with a host of factors potentially increasing the risk for osteoporosis and fractures. The aim of our study was to identify the most predictive factors for skeletal pathology in this patients.", "Using a cross-sectional study design, 146 randomly selected patients with Crohn's disease of variable disease activity who were given standard therapy to control disease activity, including glucocorticoids, and who attended the outpatient clinic of the Gastroenterology Unit on regular follow-up visits were studied. Bone mineral density (BMD) measurements and lateral X-rays of the spine were performed, and biochemical parameters of bone turnover, gonadal hormones and C-reactive protein (CRP) as markers of disease activity were measured in all patients.", 'There were 61 men and 85 women, with a mean age of 43 years and mean disease duration of 20 years. The majority of patients (86%) had been treated with glucocorticoids at some stage during their illness at a median dose of 7.5 mg/day, 43% were currently using these agents and 66% had undergone an intestinal resection. Twenty-one percent of patients had below-normal 25-hydroxy vitamin D levels. Osteoporosis was documented in 26% of patients, predominantly at the femoral neck, but also at the lumbar spine or at both sites; osteopenia was documented in 45% of patients. Prevalence of vertebral and non-vertebral fractures was, respectively, 6% and 12%. Ileum resection was the most predictive factor for osteoporosis: RR 3.84 (CI 1.24-9.77, p=0.018), followed by age: RR 1.05 (CI 1.02-1.08, p<0.001) and current or past glucocorticoid use: RR 1.94 (CI 0.92-4.10, p=0.08).\Question: Is ileum resection the most predictive factor for osteoporosis in patients with Crohn 's disease?
answer:

Our data suggest that in patients with Crohn's disease, the risk of osteoporosis is best predicted by a history of ileum resection.