instruction:
Given a passage with a context and an answer, 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.
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Context: To date, cardiac catheterization and endomyocardial biopsy have been considered the "gold standard" for rejection surveillance after heart transplantation. Factors such as patient size (i.e., infant transplantation), loss of vascular access after repeated catheterizations, and anesthesia requirements all present unique problems and risks related to pediatric rejection surveillance. Therefore, additional methods to monitor for rejection in a non-invasive, reliable and frequent manner have been sought. We studied the utility of echocardiographic measurement of the left ventricular myocardial performance index (LVMPI), a reproducible measure of combined systolic and diastolic performance, in pediatric heart transplant recipients as a method of identifying acute rejection.', 'Two-dimensional/Doppler echocardiographic studies (n = 36) were performed on 21 cardiac transplant patients (ages 6.2 to 21.9 years) at the time of endomyocardial biopsy. The LVMPI, the sum of the isovolumic contraction time and isovolumic relaxation time divided by aortic ejection time, was determined at each study, as well as other echocardiographic measures of systolic and diastolic function. Patients were grouped by concurrent histologic rejection grade and the results compared between groups.', 'Significant differences in LVMPI (p < 0.001) were noted between patients with no rejection (Grade 0; n = 23) and those with moderate to severe rejection (Grade 3; n = 5), as well as between those with no rejection and those with focal moderate (Grade 2; n = 8) rejection (p < 0.05). The LVMPI was 0.42 +/- 0.03 (mean +/- SEM) for the group without rejection, 0.57 +/- 0.06 for those with Grade 2 rejection and 0.73 +/- 0.05 for those with Grade 3 rejection. Although 9 of the 23 studies in the non-rejection group had LVMPI values exceeding 0.44 (upper threshold value), 12 of 13 patients in the rejection groups exceeded this threshold. LVMPI >or= 0.64 was associated with significant rejection in all cases in this study (n = 7). No significant differences were noted between groups for left ventricular ejection fraction or shortening fraction, percent septal or posterior wall thickening, left ventricular mass index or mitral valve deceleration time. In addition, for those individual patients with multiple studies, the LVMPI consistently increased with higher rejection grades and decreased after therapy.
Answer: In this series, increased LVMPI correlated with biopsy-proven rejection, and frequent serial assessments using this technique may provide a relatively sensitive non-invasive means of rejection surveillance after pediatric cardiac transplantation. False positive results may be encountered, likely due to alterations in diastolic function that have been previously observed in transplant recipients.
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Does increased myocardial performance index correlate with biopsy-proven rejection in pediatric heart transplant recipients?

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Context: The orphan G protein-coupled receptor (GPR) 39 was originally identified as the receptor of obestatin. In this study, the effects and mechanisms of GPR39 on cell proliferation and differentiation were investigated in cultured porcine intramuscular preadipocytes.', 'Morphology of preadipocytes and accumulated lipid droplets within cells were identified by an inverted microscope. After transfected with constructed pCMV-GPR39 plasmid, cell proliferation was measured by using methyl thiazolyl tetrazolium method, mRNA expression of GPR39, CCAAT/enhancer binding protein- (C/EBP), peroxisome proliferator-activated receptor- (PPAR), Caspase-9 and adipocyte determination and differentiation factor-1 (ADD1) was determined by RNA preparation and reverse transcription polymerase chain reaction, protein expression of phosphoinositide-3 kinase (PI3K), 3-phosphoinositide-dependent protein kinase 1, phosphorylated glycogen synthase kinase 3 (pGSK3), total Akt and phosphorylated Akt (pAkt) was analyzed by Western blot.', 'It found that GPR39 mRNA and protein were expressed in porcine intramuscular preadipocytes and its expression was significantly up-regulated after treatment with Zn(2+) whose function is found to be mediated by GPR39. Furthermore, over-expression of GPR39 further promoted the optical density value of cells, enhanced mRNA expression of PPAR, C/EBP and ADD1, and inhibited mRNA expression of Caspase-9. Protein expression of pGSK3 and pAkt was also increased by GPR39 stimulation. In addition, GPR39-induced proliferation and differentiation of porcine intramuscular preadipocytes was partially blocked by the Akt inhibitor (PDTC) and the PI3K inhibitor (LY294002).
Answer: It indicated that GPR39 was a transducer of Zn(2+), and enhanced proliferation and differentiation of porcine intramuscular preadipocytes through activation of the PI3K/Akt signaling pathway.
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Does gPR39 activate proliferation and differentiation of porcine intramuscular preadipocytes through targeting the PI3K/AKT cell signaling pathway?

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Context: To investigate the relationship between ovarian androgen excess and impaired growth hormone (GH)/insulin-like growth factor-1 (IGF-1) axis in nonobese women with polycystic ovary syndrome (PCOS).', 'A prospective, controlled clinical study.', 'Reproductive Endocrine Unit, Department of Obstetrics and Gynecology, Jinling Hospital, Nanjing University School of Clinical Medicine.', 'Six patients with PCOS with both clomiphene resistance and gonadotropin hyperreponsiveness and six controls with regular cycles, matched for age and body mass index (BMI).', 'Bilateral ovarian wedge resection (OWR) was performed to induce ovulation surgically for these refractory women with PCOS. A GH stimulation test with oral L-dopa was arranged for controls and for patients with PCOS before and again 6 months later after OWR.', 'Plasma GH, IGF-1, FSH, LH, testosterone, androstenedione, estradiol, progesterone, prolactin, insulin, and glucose.', 'Basal levels and areas under the response curve of GH and GH-IGF-1 ratio to L-dopa were significantly lower in patients with PCOS before surgery than those of controls. The OWR in patients with PCOS obviously reduced their androstenedione and testosterone levels and insulin-glucose ratios, and increased the GH and GH-IGF-1 responses to L-dopa.
Answer: Impaired somatotrophic axis caused by a defect in central dopaminergic activity may be responsible for severe anovulation in these women with PCOS, which could be reversed by removing excessive androgens with OWR.
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Does androgen excess contribute to altered growth hormone/insulin-like growth factor-1 axis in nonobese women with polycystic ovary syndrome?