TASK DEFINITION: Given a passage, 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: Despite much clinical experience, there are few published accounts of the surgical manifestations of HIV/AIDS in children and still fewer guidelines for the best or most appropriate treatment. Our primary objective was to document the incidence of HIV infection in children who presented with a surgical emergency to a major pediatric surgical unit in South Africa. If possible, we aimed to provide a description of the impact of the disease in a surgical pediatric population and to raise awareness of the mode of presentation of HIV to the pediatric surgeon in a developing nation, now that specific antiretroviral therapies are available.', 'This was a prospective observational study of consecutive surgical emergency admissions to the Division of Paediatric Surgery at the University of the Witwatersrand, Johannesburg, South Africa, between April 1 and May 31, 2005. Consent for inclusion in the study was sought in all cases. The clinical profile of children presenting during the study period was recorded. If relevant, permission was sought from the parent/guardian to undertake HIV status testing if this were not already known.', 'Three hundred ninety-one children were admitted as emergency cases during the study period. Thirty-seven (9.5%) of 391 were excluded, because consent could not be obtained, leaving 354 children. Ages ranged between 1 day and 17 years, with a median age of 3 years. The diagnosis in most was trauma/burns (42%) and abdominal emergencies (27%). Infections occurred in 13% of these patients. Human immunodeficiency virus status was already known in 10 (3%) of 354 patients, and only 18 (5%) of 344 children were tested; of these, 10 (55%) were positive. As expected, the predominant surgical presentation of HIV positive children was sepsis. The prevalence of HIV/AIDS in those children not tested is unknown.

SOLUTION: Are surgeons failing to recognize children with HIV infection?

PROBLEM: Stem cell factor (SCF) has well-known proliferative effects on hematopoietic cells. SCF also has effects on differentiation and proliferation in other cell types. Interleukin-6 (IL-6) and tumor necrosis factor (TNF)-alpha have proliferative effects in the liver. Recent studies in our laboratory have linked SCF's hepatoproliferative actions to those of IL-6, demonstrating that IL-6-induced hepatocyte proliferation depends, at least in part, on SCF. We now hypothesize that TNF-alpha's hepatoproliferative effects are also dependent on SCF.", 'In vitro studies using primary mouse hepatocytes show that SCF is induced by TNF-alpha; anti-SCF antibody treatment in this system inhibits TNF-alpha-induced hepatocyte proliferation, suggesting that TNF-alpha-induced hepatocyte proliferation is also SCF dependent. Additional in vivo experiments were performed in which wild type and/or TNF-alpha receptor-1 knockout mice (TNFR1(-/-)) were subjected to 70% hepatectomy or sham laparotomy. TNFR1(-/-) mice are known to have delayed hepatic regeneration after partial hepatectomy. Initial experiments demonstrated that the SCF receptor, c-kit, is upregulated after partial hepatectomy in wild-type mice, further emphasizing the importance of this system in the restoration of hepatic mass. SCF administration to TNFR1(-/-) mice in the context of partial hepatectomy restores hepatocyte proliferation to normal. Further, SCF administration to TNFR1(-/-) mice before hepatectomy increases phosphotyrosine signal transducer and activator (p-stat-3) levels, suggesting that SCF-induced increases in hepatocyte proliferation may also be stat-3 mediated.

SOLUTION: Are stem cell factor and its receptor , c-kit , important for hepatocyte proliferation in wild-type and tumor necrosis factor receptor-1 knockout mice after 70 % hepatectomy?

PROBLEM: Mycoplasmas are cell wall-less bacteria which encode a minimal set of proteins. In Mycoplasma hominis, the genes encoding the surface-localized membrane complex P60/P80 are in an operon with a gene encoding a cytoplasmic, nucleotide-binding protein with a characteristic Histidine triad motif (HinT). HinT is found in both procaryotes and eukaryotes and known to hydrolyze adenosine nucleotides in eukaryotes. Immuno-precipitation and BIACore analysis revealed an interaction between HinT and the P80 domain of the membrane complex. As the membrane anchored P80 carries an N-terminal uncleaved signal peptide we have proposed that the N-terminus extends into the cytoplasm and interacts with the cytosolic HinT.', 'Further characterization of P80 suggested that the 4.7 kDa signal peptide is protected from cleavage only in the membrane bound form. We found several proteins were released into the supernatant of a logarithmic phase mycoplasma culture, including P80, which was reduced in size by 10 kDa. Western blot analysis of recombinant P80 mutants expressed in E. coli and differing in the N-terminal region revealed that mutation of the +1 position of the mature protein (Asn to Pro) which is important for signal peptidase I recognition resulted in reduced P80 secretion. All other P80 variants were released into the supernatant, in general as a 74 kDa protein encompassing the helical part of P80. Incubation of M. hominis cells in phosphate buffered saline supplemented with divalent cations revealed that the release of mycoplasma proteins into the supernatant was inhibited by high concentrations of calciumions.

SOLUTION:
Is p80 , the HinT interacting membrane protein , a secreted antigen of Mycoplasma hominis?