TASK DEFINITION: In this task, you are given an abstract of article. Your task is to generate label "True" if abstract is structured, otherwise generate "False". A structured abstract is composed of a topic sentence (or key sentence), relevant supporting sentences, and a closing (or transition) sentence. This structure is key to keeping your abstract focused on the main idea and creating a clear and concise image.
PROBLEM: This study examines factors associated with caregiver burden in 82 HIV-positive (HIV+) and 162 HIV-negative (HIV-) partners of men with AIDS. We expected HIV+ caregivers to report more burden than HIV- caregivers because of the toll of their disease on their resources. HIV+ caregivers did report more burden and, compared with the HIV- caregivers, they were more religious or spiritual, had less income, and coped by using more positive reappraisal and cognitive escape-avoidance and by seeking social support. Comparisons of HIV+ caregivers with 61 HIV+ partners of healthy men indicated that most differences between HIV+ and HIV- caregivers were associated with HIV seropositivity rather than caregiving. However, of the variables associated with HIV seropositivity, only religiosity or spirituality contributed independently to burden in HIV+ caregivers, suggesting a relatively weak link between HIV seropositivity and caregiver burden. The model explained 62% of the variance in burden in HIV+ caregivers and 36% of the variance in HIV- caregivers.

SOLUTION: False

PROBLEM: Oxysterols are oxygenated cholesterol derivates that are emerging as a physiologically important group of molecules. Although they regulate a range of cellular processes, only few oxysterol-binding effector proteins have been identified, and the knowledge of their binding mode is limited. Recently, the family of G protein-coupled seven transmembrane-spanning receptors (7TM receptors) was added to this group. Specifically, the Epstein-Barr virus-induced gene 2 (EBI2 or GPR183) was shown to be activated by several oxysterols, most potently by 7,25-dihydroxycholesterol (7,25-OHC). Nothing is known about the binding mode, however. Using mutational analysis, we identify here four key residues for 7,25-OHC binding: Arg-87 in TM-II (position II:20/2.60), Tyr-112 and Tyr-116 (positions III:09/3.33 and III:13/3.37) in TM-III, and Tyr-260 in TM-VI (position VI:16/6.51). Substituting these residues with Ala and/or Phe results in a severe decrease in agonist binding and receptor activation. Docking simulations suggest that Tyr-116 interacts with the 3-OH group in the agonist, Tyr-260 with the 7-OH group, and Arg-87, either directly or indirectly, with the 25-OH group, although nearby residues likely also contribute. In addition, Tyr-112 is involved in 7,25-OHC binding but via hydrophobic interactions. Finally, we show that II:20/2.60 constitutes an important residue for ligand binding in receptors carrying a positively charged residue at this position. This group is dominated by lipid- and nucleotide-activated receptors, here exemplified by the CysLTs, P2Y12, and P2Y14. In conclusion, we present the first molecular characterization of oxysterol binding to a 7TM receptor and identify position II:20/2.60 as a generally important residue for ligand binding in certain 7TM receptors.

SOLUTION: False

PROBLEM: BACKGROUND:It is well established that a minority of celiac patients present with "classic" symptoms due to malabsorption. However, few studies have focussed on the distribution of body mass index (BMI) in celiac populations and its relationship to clinical characteristics, or on its response to treatment.
METHODS:We reviewed BMI measurements and other clinical and pathological characteristics from a database of 371 celiac patients diagnosed over a 10-yr period and seen by a single gastroenterologist. To assess response to gluten exclusion, we compared BMI at diagnosis and after 2 yr treatment in patients with serological support for dietary compliance.
RESULTS:Mean BMI was 24.6 kg/m2 (range 16.343.5). Seventeen patients (5%) were underweight (BMI <18.5), 211 (57%) were normal, and 143 (39%) were overweight (BMI 25), including 48 (13% of all patients) in the obese range (BMI 30.0). There was a significant association between low BMI and female gender, history of diarrhea, reduced hemoglobin concentration, reduced bone mineral density (BMD), osteoporosis, and higher grades (subtotal/total) of villous atrophy. Of patients compliant with a gluten-free diet, 81% had gained weight after 2 yr, including 82% of initially overweight patients.
CONCLUSIONS:Few celiac patients are underweight at diagnosis and a large minority is overweight; these are less likely to present with classical features of diarrhea and reduced hemoglobin. Failed or delayed diagnosis of celiac disease may reflect lack of awareness of this large subgroup. The increase in weight of already overweight patients after dietary gluten exclusion is a potential cause of morbidity, and the gluten-free diet as conventionally prescribed needs to be modified accordingly.

SOLUTION:
True