Meta-based association of the lipoprotein lipase gene S447X variant with hypertension and blood pressure variation

Association of the lipoprotein lipase (LPL) gene S447X variant with hypertension has been investigated extensively, whereas the results are often irreproducible. We therefore conducted a meta-analysis to examine whether S447X variant was associated with hypertension and blood pressure variation. Case-control reports published in English language and humans were identified from MEDLINE, EMBASE and Web of Science search engines as of 10 December 2009. Fixed-effects model was applied to pool data in the absence of between-studies heterogeneity, and random-effects model otherwise. A total of five studies (960 cases and 1145 controls) for hypertension and four studies (n=2777) for blood pressure were included. Compared with 447SS homogeneous carriers, those with 447X variant had a lower risk of hypertension (odds ratio (OR)=0.78; 95% confidence interval (CI): 0.62-0.98; P=0.03), and this effect reached significance under the fixed-effects model (I(2)=30% and P=0.22). Similarly, compared with 447S allele carriers, those with 447X allele carriers also had a lower risk of hypertension (OR=0.79; 95% CI: 0.64-0.98; P=0.03). In case of pregnancy-induced hypertension, no significance was observed (P>0.05). As for blood pressure association, there was no significant difference between 447X variant and 447SS homogeneous carriers for both systolic and diastolic blood pressure in the whole population, even stratified by gender (P>0.05). The Egger test told no publication bias for all associations. This meta-analysis demonstrated that LPL gene S447X variant was significantly associated with hypertension and showed no obvious relation with pregnancy-induced hypertension and blood pressure variation.

Increased lipolysis in adipose tissues is associated with elevation of systemic free fatty acids and insulin resistance in perilipin null mice

Elevated plasma levels of free fatty acids (FFAs) are thought to restrict glucose utilization and induce insulin resistance. Plasma FFA concentrations are primarily governed by lipolysis in adipocytes. Perilipin surrounds the lipid droplet in adipocytes and has a dual role in lipolysis regulation. Perilipin null mice studied by two independent laboratories exhibited similar phenotypes of reduced adipose mass and resistance to diet-induced obesity, but have inconsistent metabolic parameters such as plasma levels of FFA, glucose, and insulin. This discrepancy may be due to differences in genetic background, generation, and nutritional status of the animals examined. In this study, we examined the major metabolic parameters in 129/SvEv perilipin null mice fasted for 4 h and observed increased plasma concentrations of FFA, glycerol, glucose, and insulin. An increase in the score for the homeostasis model assessment of insulin resistance index confirmed the insulin resistance in perilipin null mice, which may be attributed to the plasma FFA elevation. Basal lipolysis was increased in adipose tissues or primary adipocytes isolated from perilipin null mice with increased mass and activity of hormone-sensitive lipase and adipose triglyceride lipase. The increased lipolytic action may accelerate FFA efflux from the adipose tissues to the bloodstream, thereby accounting for systemic FFA elevation and, hence, insulin resistance in perilipin null mice.

Low adiponectin concentration during pregnancy predicts postpartum insulin resistance, beta cell dysfunction and fasting glycaemia

AIMS/HYPOTHESIS

The postpartum phase following gestational diabetes (GDM) is characterised by subtle metabolic defects, including the beta cell dysfunction that is believed to mediate the increased future risk of type 2 diabetes in this patient population. Low circulating levels of adiponectin and increased leptin and C-reactive protein (CRP) have recently emerged as novel diabetic risk factors, although their relevance to GDM and subsequent diabetes has not been characterised. Thus, we sought to determine whether adiponectin, leptin and CRP levels during pregnancy relate to the postpartum metabolic defects linking GDM with type 2 diabetes.

METHODS

Metabolic characterisation, including oral glucose tolerance testing, was undertaken in 487 women during pregnancy and at 3 months postpartum. Based on the antepartum OGTT, there were 137 women with GDM, 91 with gestational impaired glucose tolerance and 259 with normal glucose tolerance.

RESULTS

Adiponectin levels were lowest (p < 0.0001) and CRP levels highest (p = 0.0008) in women with GDM. Leptin did not differ between the glucose tolerance groups (p = 0.4483). Adiponectin (r = 0.41, p < 0.0001), leptin (r = -0.36, p < 0.0001) and CRP (r = -0.30, p < 0.0001) during pregnancy were all associated with postpartum insulin sensitivity (determined using the insulin sensitivity index of Matsuda and DeFronzo [IS(OGTT)]). Intriguingly, adiponectin levels were also related to postpartum beta cell function (insulinogenic index/HOMA of insulin resistance; r = 0.16, p = 0.0009). Indeed, on multiple linear regression analyses, adiponectin levels during pregnancy independently predicted both postpartum insulin sensitivity (t = 3.97, p < 0.0001) and beta cell function (t = 2.37, p = 0.0181), even after adjustment for GDM. Furthermore, adiponectin emerged as a significant negative independent determinant of postpartum fasting glucose (t = -3.01, p = 0.0027).

CONCLUSIONS/INTERPRETATION

Hypoadiponectinaemia during pregnancy predicts postpartum insulin resistance, beta cell dysfunction and fasting glycaemia, and hence may be relevant to the pathophysiology relating GDM with type 2 diabetes.

Epigenetic inactivation of the miR-34a in hematological malignancies

miR-34a is a transcriptional target of p53 and implicated in carcinogenesis. We studied the role of miR-34a methylation in a panel of hematological malignancies including acute leukemia [acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL)], chronic leukemia [chronic lymphocytic leukemia (CLL) and chronic myeloid leukemia (CML)], multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL). The methylation status of miR-34a promoter was studied in 12 cell lines and 188 diagnostic samples by methylation-specific polymerase chain reaction. miR-34a promoter was unmethylated in normal controls but methylated in 75% lymphoma and 37% myeloma cell lines. Hypomethylating treatment led to re-expression of pri-miR-34a transcript in lymphoma cells with homozygous miR-34a methylation. In primary samples at diagnosis, miR-34a methylation was detected in 4% CLL, 5.5% MM samples and 18.8% of NHL at diagnosis but none of ALL, AML and CML (P = 0.011). In MM patients with paired samples, miR-34a methylation status remained unchanged at progression. Amongst lymphoid malignancies, miR-34a was preferentially methylated in NHL (P = 0.018), in particular natural killer (NK)/T-cell lymphoma. In conclusion, amongst hematological malignancies, miR-34a methylation is preferentially hypermethylated in NHL, in particular NK/T-cell lymphoma, in a tumor-specific manner, therefore the role of miR-34a in lymphomagenesis warrants further study.

The response to short-term intensive insulin therapy in type 2 diabetes

AIM

Although a short course of intensive insulin therapy (IIT) can improve beta-cell function and glycaemic control in most patients with newly diagnosed type 2 diabetes (T2DM), the impact of this intervention in diabetes of longer duration has not been carefully studied. Thus, we sought to evaluate the effect of short-term IIT in patients with established T2DM.

METHODS

Thirty-four patients, with diabetes of mean 5.9 +/- 6.6 years duration, underwent 4-8 weeks of IIT, with 4-h meal test administered at baseline and at 1 day post-IIT. A positive clinical response was defined as fasting glucose < 7.0 mmol/l off any antidiabetic therapy at the latter test.

RESULTS

A positive response was achieved in 68% (n = 23) of the subjects. At baseline meal test, the responders had lower glucose levels than the non-responders from 120 to 240 min (all timepoints p < or = 0.0008) and higher late incremental area-under-the-C-peptide-curve (AUC(Cpep)), particularly from 60 to 150 min (all p < 0.005). Beta-cell function (ratio of AUC(Cpep) to AUC(gluc) divided by HOMA-IR) was similar between the groups at baseline (median 54.1 vs. 51.3, p = 0.62) but after IIT was significantly higher in the responders (109.3 vs. 57.4, p = 0.009). At baseline, the strongest predictors of the change in beta-cell function were glucose levels between 180 and 240 min (all r = -0.5, p = 0.005) and incremental AUC(Cpep) from 120 to 180 min (all r > or = 0.66, p < or = 0.0001), both reflecting late-phase insulin secretion.

CONCLUSIONS

The clinical response to short-term IIT is variable, consistent with the heterogeneity of T2DM. However, preserved late-phase insulin secretion may identify those patients who can benefit from this intervention with improved beta-cell function.

Effects of physicochemical factors on Cr(VI) removal from leachate by zero-valent iron and alpha-Fe(2)O(3) nanoparticles

The effects of nanoparticle dosage, initial hexavalent chromium concentration, pH value, reaction temperature, and initial concentration of humic acid (HA) on chromate (CrO(4)(2-)) removal from landfill leachate by nanoscale zero-valent iron (NZVI) and hematite (alpha-Fe(2)O(3)) nanoparticles were examined in the present investigations. The Cr(VI) removal rate decreased as the initial Cr(VI) concentration and the reaction temperature increased, whereas corresponding removal rate by NZVI was higher than that of alpha-Fe(2)O(3). The optimum pH for the removal of Cr(VI) by NZVI was found to be 5.0 and more than 99.0% of Cr(VI) was removed within 5 h. However, the removal rate by alpha-Fe(2)O(3) decreased as pH increased. Presence of HA resulted in substantial reduction in the rate and extent of Cr(VI) removal by NZVI, whereas Cr(VI) removal rate by alpha-Fe(2)O(3) did not significantly decrease as HA concentration increased from 0.5 g/L to 3.0 g/L. Increasing the dosage of nanoparticles enhanced the rate constant and the removal of Cr(VI) by NZVI and alpha-Fe(2)O(3) followed pseudo-first-order reaction kinetics. The information should be very useful for the successful application of NZVI and alpha-Fe(2)O(3) for the treatment of groundwater or raw wastewater.

The Molecular Anatomy of Breast Cancer Stroma; Independent Prognostic Role in ER-Positive and ER-Negative Cancers

BackgroundIn this paper we examine the various molecular components of a breast cancer stromal gene signature and correlate these with clinical phenotype and outcome including prognosis and response to preoperative chemotherapy.MethodsWe compared Affymetrix HGU133A-based gene expression profiles of 37 matching core needle biopsies (CNB) and fine-needle aspirations (FNA) from the same cancers. Genes over-expressed in CNB relative to the FNA were defined as the “stromal signature”. Gene expression data from 56 breast cancer cell lines, two separate neoadjuvant data sets (n=233, n=103), 3 independent cohorts of node negative, untreated patients (n=286, n=198, n=200) and 259 estrogen receptor-positive (ER+) tamoxifen-treated patients were used to assess the prognostic and predictive values of these genes in ER+ and ER- cancers separately. Univariate and multivariate Cox analyses were performed. Metagenes were defined as average expression of co-clustered genes.Results293 probe sets (206 genes) were significantly over-expressed in the CNBs (false discovery rate ≤ 0.001, fold-change ≥ 3). These genes overlapped with previously reported stromal signatures and fell into several co-expression clusters including a B-cell/Plasma Cell (B-cell), Dendritic cell, extracellular matrix (ECM), and TGFb-receptor metagenes. Interestingly, ER+ and ER- cancers showed a significantly different stroma-gene expression pattern, and many stromal genes were also differentially expressed between ER+ and ER- breast cancer cell lines. The ECM and TGFb metagenes had modest and variable prognostic value across different datasets in both ER groups. The Dendritic and B cell metagenes were highly co-expressed, but the B-cell metagene had more robust and consistent prognostic value. The B-cell metagene was statistically significant prognostic in univariate and multivariate analysis in ER+/High proliferative and ER- tumors, but it was not prognostic in ER+/Low proliferative tumors. In the 3 different node negative, untreated patient cohorts, the ER+/High proliferative cancers in the lowest B-cell metagene tertile had 10-year distant metastasis free survival (DMFS) of 0.18 (0.07-0.46), 0.22 (0.06-0.75), and 0.44 (0.21-0.92) compared to 0.71 (0.54-0.94), 0.89 (0.71-1.00) and 0.89 (0.71-1.00) in the highest tertile. Among the ER- cancers, the lowest B cell metagene group had 10-year DMFS of 0.57 (0.44-0.75), 0.63 (0.48-0.83), and 0.44 (0.25-0.76) compared to 0.93 (0.81-1.00), 0.83 (0.64-1.00) and 0.83 (0.58-1.00) in the highest B-cell metagene group in each prognostic dataset, respectively. The B-cell metagene was also prognostic in univariate (HR 0.83 (0.71-0.98) p=0.03) and multivariate (HR 0.80 (0.68-0.94) p=0.007) analysis in the Tamoxifen-treated cohort. None of the above stromal metagenes showed reproducible association with response to chemotherapy.ConclusionsThe B-cell/Plasma cell metagene component of the “stroma-related genes” is a robust and reproducible prognostic marker in ER+/High proliferative and also in ER- cancers. Other stromal genes are variably expressed in ER+ and ER- tumors and many are also expressed by neoplastic cells in culture and by primary tumors and carry less reproducible prognostic value.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 105.

Evaluation of the Predictive Performance and Regimen Specificity of a 30-Gene Predictor of Pathologic Complete Response in a Prospective Randomized Neoadjuvant Clinical Trial for Stage I-III Breast Cancer

Purpose: To prospectively evaluate in a randomized trial if a previously reported multigene predictor of pathologic complete response (pCR) to preoperative weekly paclitaxel and fluorouracil-doxorubicin-cyclophosphamide (T/FAC) chemotherapy can accurately predict pCR to neoadjuvant T/FAC chemotherapy, and if it also predicts pCR to FAC only chemotherapy. Furthermore, it is unknown if the T/FAC regimen is superior to 6 courses of FAC; therefore we compare the pCR rates for patients who receive T/FAC versus FACx6 preoperative chemotherapy.Materials and Methods: Patients with stage I-III breast cancer (n=273) were randomly assigned to receive either 12 courses of weekly paclitaxel followed by 4 courses of FAC (T/FAC, n=138), or 6 courses of FAC (FACx6, n=135) neoadjuvant chemotherapy. All patients underwent a pretreatment FNA biopsy of the tumor for gene expression profiling on oligonucleotide microarrays, and treatment response prediction (pCR versus residual disease, RD) was performed using the multigene predictor. Predicted and observed pathologic responses were compared independently in the two treatment arms.Results: The pCR rate was 19% with T/FAC and 9% with FACx6 (p&lt;0.05). In the T/FAC arm, the positive predictive value (PPV) of the genomic predictor was 38% (95%CI:21-56%), the negative predictive value (NPV) 88% (CI:77-95%), sensitivity 63% (CI:38-84%), specificity 72% (CI:60-82%), and the AUC 0.711. In the FAC only treatment arm, the PPV was 9% (CI:1-29%), the NPV 92% (CI:83-97%), sensitivity 29% (CI:4-71%), specificity 75% (CI:64-84%), and the AUC 0.584. This suggests that the genomic predictor is regimen-specific. In a multivariate analysis including age, tumor size, nodal status, histologic grade, HER2 and estrogen receptor (ER) status and the genomic predictor, only ER status was a significant predictor of pCR.Discussion: Pathologic complete response rate was significantly higher in the T/FAC arm compared to the FACx6 arm indicating a higher efficacy of the paclitaxel containing arm. Patients who were predicted to achieve pCR to T/FAC had a significantly higher pCR rate (38%) than unselected patients (19%) or patients predicted to have RD (12%) when treated with this regimen. These results confirm that the multigene predictor can identify patients with greater than average sensitivity to T/FAC chemotherapy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 101.

Clinical Subtype-Derived p53 Gene Signature Is Predictive of Prognosis and Response to Chemotherapy in ER-Positive but Not in ER-Negative Breast Cancers

BackgroundBreast cancer is a collection of molecularly distinct neoplastic diseases and therefore, we hypothesized that p53 gene mutations may lead to different transcriptional changes in the different molecular subtypes and these may translate into subtype-dependent prognostic and predictive values.MethodsWe developed gene expression-based predictors of p53 status separately for estrogen receptor-positive (ER+) and -negative (ER-) breast cancers from a publicly available data set with known p53 mutation status (n=251). We validated the two signatures on an independent cohort of cancers (n=103) with known p53 functional status and tested their prognostic and predictive values on two other cohorts of breast cancers that received no systemic adjuvant therapy (n=255; n=198), and on one cohort of ER+ patients treated with adjuvant tamoxifen (n=277). We also examined if the p53 signatures were associated with chemotherapy sensitivity in ER+ and ER- cancers, respectively in two separate neoadjuvant data sets (n=233; n=103).ResultsWe developed a 39-gene p53 signature derived from 213 ER+ and a 30-gene p53 signature derived from 38 ER- breast cancers with no overlapping genes. External validation showed a sensitivity and specificity of 89% and 54%, respectively for the 39-gene signature in ER+ breast cancers; and 82% and 61%, respectively for the 30-gene signature in ER- cancers. The 39-gene signature was predictive of worse distant metastasis free survival (DMFS) in ER+ cancers with p53 dysfunction in both prognostic data sets (Hazard ratio (HR): 2.3 (95% confidence interval (CI):1.25-4.23, p=0.005 and HR:2.17 (95%CI:0.85-5.56, p=0.09). It remained predictive of worse DMFS even after tamoxifen adjuvant therapy (HR=2.43, 95%CI: 1.35-4.38, p&lt;0.0001). In contrast it was associated with higher chemotherapy sensitivity in ER+ cancers. Its predictive accuracy for pathologic complete response was of 68% (95%CI: 64-70%), sensitivity 89% (95%CI: 58-98%), specificity 67% (95%CI: 65-68%), positive predictive value 15% (95%CI: 10-17%), and negative predictive value 99% (95%CI: 96-100%) in ER+ cancers. The prognostic and predictive values remained significant in multivariate analysis. The same 39-gene signature was not prognostic or predictive in ER- cancers. The 30-gene signature derived from ER- tumors had no chemotherapy response predictive value in either ER- or ER+ cancers. The p53 dysfunctional cases showed better survival in the absence of any adjuvant therapy among ER- cancers. It had no prognostic value in ER+ cancers.ConclusionThese observations support the hypothesis that predictive or prognostic biomarkers may be best developed separately for different clinical and molecular subsets of breast cancer. P53 dysfunction is clinically most relevant in ER+ breast cancers.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6122.

Antigens containing TAVSPTTLR tandem repeats could be used in assaying antibodies to Classical swine fever virus

Classical swine fever virus (CSFV) causes a highly contagious and often fatal viral disease in pigs. The highly conserved epitope TAVSPTTLR on the glycoprotein E2 was shown to be suitable for differentiation of CSFV from other pestiviruses. In this study, we found that swine CSFV antisera contained TAVSPTTLR-related rather than TAVSPTTLR-specific CSFV antibodies. The CSFV antisera reacted only to some extent with a synthetic TAVSPTTLR-containing peptide, but inhibited the binding of TAVSPTTLR-specific antibodies to the viral antigen. Since chimeric antigens containing TAVSPTTLR tetramers or hexamers were recognized by the swine CSFV antisera, such antigens could be potentially applied to the detection of CSFV antibodies. These results might be helpful in designing a TAVSPTTLR epitope-based CSFV vaccine and a corresponding serological test.

17beta-Estradiol modulates local cardiac renin-angiotensin system to prevent cardiac remodeling in the DOCA-salt model of hypertension in rats

Ventricular remodeling can play a detrimental role in the progression of cardiovascular diseases, leading to heart failure. The current study was designed to investigate the effects of 17beta-estradiol (E2) on cardiac remodeling. Cardiac fibrosis and hypertrophy were examined in deoxycorticosterone acetate (DOCA)-salt treated rats with chronic, six-week administration of two different doses of E2. Bilaterally ovariectomized (Ovex) female Sprague-Dawley rats were randomly assigned to one of the following groups: Ovex-control; Ovex-DOCA; Ovex-DOCA+low-dose E2 (1.66 microg/day); or Ovex-DOCA+high-dose E2 (2.38 microg/day). All DOCA-treated rats were uninephrectomized and drinking water was replaced by 0.15M NaCl solution for the remainder of the study period. DOCA-salt treatment resulted in a significant increase in blood pressure, which was not altered by estrogen replacement. Histological examinations revealed marked cardiac remodeling (both ventricular hypertrophy and interstitial fibrosis) with DOCA treatment, which was attenuated in animals receiving estrogen therapy. Western blot analysis demonstrated increased cardiac levels of angiotensin converting enzyme (ACE) with DOCA treatment, which was attenuated by E2 replacement. Furthermore, increased levels of cardiac angiotensin converting enzyme 2 (ACE2) protein were observed in animals receiving high-dose E2 replacement. These findings suggest that physiologically relevant estrogen replacement therapy has blood pressure-independent cardioprotective effects, which are possibly mediated through modulation of the cardiac renin-angiotensin system.

Evaluation of proposed oral disposition index measures in relation to the actual disposition index

Aims While the disposition index provides a useful measure of B-cell function, its calculation requires the performance of a frequently sampled intravenous glucose tolerance test (FSIVGTT). Recently, the demonstration of a hyperbolic relationship between indices of insulin secretion and insulin sensitivity derived from the oral glucose tolerance test (OGTT) has led to the introduction of two novel OGTT-based measures of B-cell function analogous to the disposition index: (i) the insulin secretion-sensitivity index-2 (ISSI-2) (defined as the ratio of the area-under-the-insulin-curve to the area-under-the-glucose curve, multiplied by the Matsuda index) and (ii) insulinogenic index (IGI)/fasting insulin. However, neither of these two measures has been directly compared with the disposition index. Methods Two hundred and thirteen non-diabetic children (122 boys, 91 girls) underwent both OGTT and FSIVGTT, allowing for the calculation of ISSI-2, IGI/fasting insulin and the disposition index. Results ISS1-2 and IGI/fasting insulin were strongly correlated with each other (r = 0.82, P < 0.0001). Both measures correlated with the disposition index, with ISSI-2 showing a modestly stronger association (ISSI-2: r = 0.24, P = 0.0003; IGI/fasting insulin: r = 0.21, P = 0.0022). Standardized linear regression analyses confirmed that the relationship between log ISSI-2 and the disposition index (standardized regression coefficient = 0.224, P = 0.001) was stronger than that between log IGI/fasting insulin and the disposition index (standardized regression coefficient = 0.166, P = 0.015). Conclusions The OGTT-derived measures ISSI-2 and IGI/fasting insulin exhibit modest correlations with the disposition index. These relationships require further assessment in other patient populations.

Projections of RFamide-related peptide-3 neurones in the ovine hypothalamus, with special reference to regions regulating energy balance and reproduction

RFamide-related peptide-3 (RFRP-3) is a neuropeptide produced in cells of the paraventricular nucleus and dorsomedial nucleus of the ovine hypothalamus. In the present study, we show that these cells project to cells in regions of the hypothalamus involved in energy balance and reproduction. A retrograde tracer (FluoroGold) was injected into either the arcuate nucleus, the lateral hypothalamic area or the ventromedial nucleus. The distribution and number of retrogradely-labelled RFRP-3 neurones was determined. RFRP-3 neurones projected to the lateral hypothalamic area and, to a lesser degree, to the ventromedial nucleus and the arcuate nucleus. Double-label immunohistochemistry was employed to identify cells receiving putative RFRP-3 input to cells in these target regions. RFRP-3 cells were seen to project to neuropeptide Y and pro-opiomelanocortin neurones in the arcuate nucleus, orexin and melanin-concentrating hormone neurones in the lateral hypothalamic area, as well as orexin cells in the dorsomedial nucleus and corticotrophin-releasing hormone and oxytocin cells in the paraventricular nucleus. Neurones expressing gonadotrophin-releasing hormone in the preoptic area were also seen to receive input from RFRP-3 projections. We conclude that RFRP-3 neurones project to hypothalamic regions and cells involved in regulation of energy balance and reproduction in the ovine brain.

Evidence that RF-amide related peptides are inhibitors of reproduction in mammals

Gonadotropin releasing hormone (GnRH) secretion represents the final common pathway in the control of the reproductive axis. Dogma has been that GnRH is solely responsible for the control of gonadotropin secretion, but emerging data presents a strong case for the existence of a gonadotropin inhibitory hormone in mammals. This evidence arose from initial work in avian species to isolate and identify a factor that inhibited gonadotropin release, which is known as gonadotropin inhibitory hormone (GnIH). The mammalian ortholog of avian GnIH is named RF-amide related peptide (RFRP). There are two forms of RFRP in mammals, RFRP-1 and RFRP-3 encoded by a single gene, but there has been skepticism and controversy as to whether these peptides play a significant role in the regulation of gonadotropin secretion. There is now a significant body of evidence that one or more RFRP exists in mammals and acts as an inhibitor of GnRH and/or gonadotropin secretion. Moreover, RFRP-producing neurons have been shown to transmit information to GnRH cells and/or gonadotropes in relation to seasonal status and to coordinate events around the preovulatory luteinizing hormone surge. This review will focus on the significant advances in RFRP research in mammalian species.

Discovery of a tumor-specific biomarker for gastric cancer using proteomic analysis in tissue and serum

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Background: Gastric cancer is curable at an early stage. However, most cases are diagnosed at an advanced stage because of the lack of screening programs. Therefore, for early detection, there is a need for serum biomarkers to be identified. Methods: We explored surface-enhanced laser desorption/ionization time-of-flight mass spectrometry to elucidate potential protein biomarkers of gastric cancer. Twenty-one resected gastric cancer samples were compared with matched adjacent normal mucosa samples. Serum from patients with gastric cancer (n=51) was compared with patients with benign gastric diseases (n=29). Samples were analyzed on Cu2+-loaded IMAC protein chips via surface-enhanced laser desorption /ionization time-of-flight mass spectrometry. Results: Comparisons of surface-enhanced laser desorption /ionization time-of-flight mass spectrometry spectra of 21 gastric cancer tissue extracts with paired adjacent normal mucosa showed a total of 56 differentially expressed protein peaks (p<0.05; Wilcoxon test). Twenty-two were up-regulated in gastric cancer tissue, whereas 34 were down-regulated. The surface- enhanced laser desorption /ionization time-of-flight mass spectrometry spectra of serum contained 130 peaks, of which 67 were significantly associated with gastric cancer (p<0.05; Wilcoxon test). We found five proteomic features (mass charge values of 2273, 3143, 3372, 3444, 3485) that were significantly up-regulated in both gastric cancer tissue and serum from gastric cancer patients. The peak intensities of tumor-specific proteomic features were used to develop a linear regression model for calculating a diagnostic index. The area under the receiver operating characteristic curve of the corresponding diagnostic index was 0.87. Conclusions: Serum biomarker panels associated with tumor tissue are capable of distinguishing gastric cancer patients from non-cancer ones.

No significant financial relationships to disclose.

Comparison of progression-free survival (PFS) and tumor response as endpoints for predicting overall survival (OS) in untreated extensive-stage small cell lung cancer (ED-SCLC): Findings based on North Central Cancer Treatment Group (NCCTG) trials

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Background: Historically, tumor response has been the primary endpoint in phase II (P2) trials in ED-SCLC. We investigated the suitability of alternate PFS based endpoints to predict OS as early evidence of efficacy in the P2 setting. Methods: Individual patient (pt) data from 942 pts from 11 previously untreated ED-SCLC P2 and phase III (P3) platinum- or paclitaxel-based treatment trials were pooled. Best response (BR), response confirmed (RC), objective status at 16 weeks (RR16), and PFS rate at 5 and 6 months were considered. Percent agreement (PA) and kappa (k) for PFS5, PFS6, BR, RC, and RR16 with OS at 12 months (OS12) was calculated on a per-pt basis and predictive utility was assessed using the area under the receiver operating characteristic (A- ROC) curve in logistic models. Cox models were used to assess the prognostic impact of the endpoints on subsequent survival, using landmark analysis. Results: The median OS and PFS were 9.6 m and 5.5 m, respectively. PFS5 and PFS6 had the highest PA, k, and A-ROC values, and were predictive of subsequent survival in the landmark analysis (p <0.0001; c-statistics ≥ 0.60). While RR16 and BR were significantly associated with subsequent survival (p<0.0001, c-statistics of 0.61 and 0.57, respectively) the PA, k, and A-ROC values were lower. Conclusions: PFS rate at 5 and 6 months is more predictive of 12-month OS and subsequent survival than tumor response in untreated ED-SCLC. PFS based endpoints should be routinely used as primary endpoints in P2 trials within ED-SCLC.

[Table: see text]

No significant financial relationships to disclose.

Impact of surface chemistry on grain boundary induced intrinsic stress evolution during polycrystalline thin film growth

First principles calculations were integrated with cohesive zone and growth chemistry models to demonstrate that adsorbed species can significantly alter stresses associated with grain boundary formation during polycrystalline film growth. Using diamond growth as an example, the results show that lower substrate temperatures increase the hydrogen content at the surface, which reduces tensile stress, widens the grain boundary separations, and permits additional atom insertions that can induce compressive stress. More generally, this work demonstrates that surface heteroatoms can lead to behavior which is not readily described by existing models of intrinsic stress evolution.

Lignite aided dewatering of digested sewage sludge

Mechanical dewatering is commonly used to increase the solids content of municipal sludge prior to its disposal. However, if the rate of filtration is slow, mechanical dewatering can be expensive. In this study, the use of lignite to improve the sludge dewatering is investigated. The effectiveness of lignite conditioning of polyelectrolyte-flocculated sludge is examined using mechanical compression tests. Results show that lignite conditioning in conjunction with polyelectrolyte flocculation gives much better dewatering than the polyelectrolyte flocculation alone. Using Darcy's filtration theory, the specific cake resistance and permeability of the compressed cakes are obtained. Both of these parameters are significantly improved after lignite conditioning. Mercury porosimetry tests on compressed cakes show that the porosity of the lignite-conditioned sludge cake is much higher than that of the polyelectrolyte-flocculated sludge and it increases with increasing doses of lignite. The mercury porosimetry results show that the lignite pore volume of pores greater than 0.5 microm are reduced with increasing sludge ratio indicating that sludge is trapped within these pores, whereas smaller pores are unaffected. The yield stress curves for sludge, lignite and sludge-lignite mixtures show that the sludge filter cake is very compressible, but the lignite-conditioned cake has a range of compressibility which although more than lignite indicate that the cake is relatively incompressible at low pressures. Thus, lignite conditioning acts to maintain the permeability of the filter cake during compression dewatering by resisting cake compression. This leads to a trade-off between the rate of dewatering and the solids content of the compressed cake. With lignite conditioning, the dewatering rate can be increased by a factor of five for the same degree of water removal.