Short-term modulation at synapses between neurons in laminae II-V of the rodent spinal dorsal horn

Unitary excitatory (EPSP) and inhibitory (IPSP) postsynaptic potentials (PSPs) were evoked between neurons in Rexed's laminae (L)II-V of spinal slices from young hamsters (7-24 days old) at 27°C using paired whole cell recordings. Laminar differences in synaptic efficacy were observed: excitatory connections were more secure than inhibitory connections in LII and inhibitory linkages in LII were less reliable than those in LIII-V. A majority of connections displayed paired-pulse facilitation or depression. Depression was observed for both EPSPs and IPSPs, but facilitation was seen almost exclusively for IPSPs. There were no frequency-dependent shifts between facilitation and depression. Synaptic depression was associated with an increased failure rate and decreased PSP half-width for a majority of connections. However, there were no consistent changes in failure rate or PSP time course at facilitating connections. IPSPs evoked at high-failure synapses had consistently smaller amplitude and showed greater facilitation than low-failure connections. Facilitation at inhibitory connections was positively correlated with synaptic jitter and associated with a decrease in latency. At many connections, the paired-pulse ratio varied from trial to trial and depended on the amplitude of the first PSP; dependence was greater for inhibitory synapses than excitatory synapses. Paired-pulse ratios for connections onto neurons with rapidly adapting, "phasic" discharge to depolarizing current injection were significantly greater than for connections onto neurons with tonic discharge properties. These results are evidence of diversity in synaptic transmission between dorsal horn neurons, the nature of which may depend on the types of linkage, laminar location, and intrinsic firing properties of postsynaptic cells.

Glucose metabolism-related protein 1 (GMRP1) regulates pancreatic beta cell proliferation and apoptosis via activation of Akt signalling pathway in rats and mice

AIMS/HYPOTHESIS

We attempted to elucidate the impacts on and possible mechanisms by which glucose metabolism-related protein 1 (GMRP1) affects beta cell survival.

METHODS

Adenovirus-mediated GMRP1 overproduction and siRNA-mediated knockdown were performed in INS-1E cells and rat islets, after which cell proliferation or apoptosis were determined, and phosphorylation of Akt and BCL2-associated agonist of cell death (BAD) investigated. INS-1E cells and rat islets were cultured at 5.6 (low) or 25 mmol/l (high) glucose for 24 or 48 h, and cell proliferation or apoptosis and GMRP1 levels were investigated. INS-1E cells were treated for 24 h with 0, 10, 50 and 100 nmol/l insulin, and GMRP1 levels were determined. After INS-1E cells were transfected with siRNA for 72 h, high glucose-induced cell proliferation and insulin-stimulated Akt phosphorylation were investigated. Glucose-infused rat models were established and beta cell proliferation and mass were evaluated. Levels of GMRP1, and phosphorylation of Akt and BAD were determined in glucose-infused islets. The GMRP1-mediated Akt pathway was also investigated in db/db mice.

RESULTS

Overproduction of GMRP1 promoted beta cell proliferation via increased phosphorylation of Akt. Knockdown of Gmrp1 (also known as Btbd10) reduced phosphorylation of Akt with enhanced beta cell apoptosis. High glucose increased GMRP1 levels and cell proliferation in INS-1E cells and islet cells. Knockdown of Gmrp1 decreased high glucose-induced cell proliferation and insulin-stimulated Akt phosphorylation. Increased GMRP1 levels were involved in the enhancement of beta cell proliferation and mass in glucose-infused islets. Decreased GMRP1 levels may participate in beta cell apoptosis of db/db mice.

CONCLUSIONS/INTERPRETATION

GMRP1 regulates pancreatic beta cell proliferation and apoptosis via activation of Akt signalling pathway.

"Ulm pouch" technique for total gastrectomy. Chinese experiences

AIM

"Ulm pouch" jejunal interposition reconstruction for total gastrectomy was applied in 62 patients in China, and its morphology was observed by virtual endoscopy.

METHODS

The study enrolled 220 patients who underwent total gastrectomy. Among them 62 underwent "Ulm pouch" reconstruction. Patients were 34 men and 28 women, with a mean age of 56 years (range 23-79). Twenty-two patients had underlying diseases, including hypertension and coronary disease, diabetes mellitus, chronic obstructive pulmonary disease (COPD), and malnutrition. An "Ulm pouch" was made from a jejunal segment by using staplers. An esophago-jejuno anastomosis and an end-to-end anastomosis of the distal end of the pouch to the duodenum were also performed by hand sutures or a stapler. The dimensions of the "Ulm pouch" were measured in 10 randomly selected patients, and we observed the pouch's morphology by virtual endoscopy in 13 patients. We performed Roux-Y reconstruction for the remaining patients. Fifty patients received adjuvant chemotherapy and all patients were followed for one to two years postoperatively.

RESULTS

All operations were successful. "Ulm pouch" in size and shape were similarly like actual stomach. Patients regained their appetite within three days of the operation. At one- to two-month postoperative follow-up, patients' nutritional condition had improved and they gained 2-5 kg of body weights. Complications included postoperative cholecystitis, jejuno-duodenal anastomosis leakage and upper gastric bleeding.

CONCLUSION

"Ulm pouch" for total gastrectomy is a safe procedure for alimentary reconstruction. The use of linear and circular staplers simplifies the procedure and reduces operative time. Virtual endoscopy showed that the morphology of the pouch is similar to the native stomach. "Ulm pouch" reconstruction results in a good postoperative quality of life and favorable prognosis.

Characterization of nanoscale mechanical heterogeneity in a metallic glass by dynamic force microscopy

We report nanoscale mechanical heterogeneity of a metallic glass characterized by dynamic force microscopy. Apparent energy dissipation with a variation of ~12%, originating from nonuniform distribution of local viscoelasticity, was observed. The correlation length of the heterogeneity was measured to be ~2.5 nm, consistent with the dimension of shear transformation zones for plastic flow. This study provides the first experimental evidence on the nanoscale viscoelastic heterogeneity in metallic glasses and may fill the gap between atomic models and macroscopic glass properties.

GRP78 promoter polymorphism rs391957 as potential predictor for clinical outcome in gastric and colorectal cancer patients

BACKGROUND

Recently, the analysis of gastric and colorectal tumor specimens determined that 78-kiloDalton glucose-regulated protein (GRP78), an endoplasmic reticulum chaperone, up-regulation serves as an efficient mechanism protecting cells against apoptosis and can confer drug resistance. We tested whether functional polymorphisms within the GRP78 gene are related to clinical outcome in gastric and colorectal cancer (CRC) patients.

PATIENTS AND METHODS

Blood samples of 234 stage II/III CRC patients at the University of Southern California (USC) and formalin-fixed paraffin-embedded tissues of 137 patients with localized gastric adenocarcinoma (GA) at USC and Memorial Sloan-Kettering Cancer Centers were obtained. GRP78 polymorphisms analyzed on germline DNA were correlated with clinical outcome using univariate and multivariate analyses.

RESULTS

GA patients with the combined GRP78 rs391957 C/T and T/T genotype were at higher risk for tumor recurrence and death [hazard ratio (HR) 2.61; P < 0.001 and HR 3.17; P < 0.001, respectively], than those with C/C. These findings were subsequently tested in a CRC cohort where patients with the homozygous T/T genotype were at highest risk for tumor recurrence (HR 2.61; P = 0.015). The results remained significant after adjusting for clinicopathologic determinants.

CONCLUSION

These data provide the first evidence that the GRP78 rs391957 polymorphism can predict clinical outcome in localized GA and locally advanced CRC patients.

Metformin vs thiazolidinediones for treatment of clinical, hormonal and metabolic characteristics of polycystic ovary syndrome: a meta-analysis

OBJECTIVES

Insulin-sensitizing drugs (ISDs) have been advocated for the long-term treatment of polycystic ovary syndrome (PCOS). It is therefore important to compare the efficacy and safety of ISDs such as metformin and thiazolidinediones (TZDs) for the treatment of this syndrome.

METHODS

A meta-analysis to assess the effectiveness and safety of metformin vs TZDs (including pioglitazone and rosiglitazone) in the treatment of PCOS was conducted, using MEDLINE (1966-May 2010) and EMBASE (1988-May 2010) to select randomized controlled trials comparing clinical, hormonal and metabolic results.

RESULTS

Ten trials were included. TZDs were superior to metformin in reducing serum levels of free testosterone (P=0.03) and dehydroepiandrosterone sulfate (DHEA) (P=0.002) after 3 months treatment. Decreases in triglyceride levels were more pronounced with metformin after 6 months (P<0.0001). Decreases in body mass index (BMI) were greater with metformin treatment as assessed at 3 and 6 months (P<0.00001). There were no significant between-group differences concerning improvements in ovulation, pregnancy rate, menstrual patterns or insulin sensitivity, or changes in serum levels of androstenedione, luteinizing hormone, follicle-stimulating hormone, total cholesterol, low-density lipoprotein C or insulin. Metformin caused a significantly higher incidence of side effects such as nausea, diarrhoea and abdominal cramping (P<0.00001). Significant between-study heterogeneity was detected for several variables assessed.

CONCLUSIONS

The findings from this meta-analysis do not indicate that metformin is superior to TZD's for the treatment of PCOS or vice versa. Between studies, heterogeneity was a major confounder. A large scale, well-designed, randomized, controlled trial is needed to further address this issue.

LeERF-1, a novel AP2/ERF family gene within the B3 subcluster, is down-regulated by light signals in Lithospermum erythrorhizon

We previously showed that ethylene might be involved in the process of shikonin biosynthesis regulated by light signals. Here, we cloned a full-length cDNA of LeERF-1, a putative ethylene response factor gene, from Lithospermum erythrorhizon using the RACE (rapid amplification of cDNA ends) method. Phylogenetic analysis revealed that LeERF-1 was classified in the B3 subfamily, together with ERF1 and ORA59 of Arabidopsis. Heterologous expression of LeERF-1 in Arabidopsis showed that LeERF-1:eGFP fusion protein was precisely localised to the nucleus, implying that it might function as a transcription factor. Detailed expression analysis with real-time PCR showed that LeERF-1 was significantly down-regulated by white, blue and red light, although the inhibitory effect of red light was relatively weak compared to other light conditions. Tissue-specific expression analysis also indicated that LeERF-1 was dominantly expressed in the roots, which grow in soil in darkness. These patterns are all consistent with the effects of different light signals on regulating formation of shikonin and its derivatives, indicating that LeERF-1 might be a crucial positive regulator, like other B3 subfamily proteins (such as ORCA3 and ORA59), in regulating biosynthesis of secondary metabolites.

Large-scale meta-analysis of interleukin-1 beta and interleukin-1 receptor antagonist polymorphisms on risk of radiographic hip and knee osteoarthritis and severity of knee osteoarthritis

OBJECTIVE

To clarify the role of common genetic variation in the Interleukin-1β (IL1B) and Interleukin-1R antagonist (IL1RN) genes on risk of knee and hip osteoarthritis (OA) and severity of knee OA by means of large-scale meta-analyses.

METHODS

We searched PubMed for articles assessing the role of IL1B and IL1RN polymorphisms/haplotypes on the risk of hip and/or knee OA. Novel data were included from eight unpublished studies. Meta-analyses were performed using fixed- and random-effects models with a total of 3595 hip OA and 5013 knee OA cases, and 6559 and 9132 controls respectively. The role of ILRN haplotypes on radiographic severity of knee OA was tested in 1918 cases with Kellgren-Lawrence (K/L) 1 or 2 compared to 199 cases with K/L 3 or 4.

RESULTS

The meta-analysis of six published studies retrieved from the literature search and eight unpublished studies showed no evidence of association between common genetic variation in the IL1B or IL1RN genes and risk of hip OA or knee OA (P>0.05 for rs16944, rs1143634, rs419598 and haplotype C-G-C (rs1143634, rs16944 and rs419598) previously implicated in risk of hip OA). The C-T-A haplotype formed by rs419598, rs315952 and rs9005, previously implicated in radiographic severity of knee OA, was associated with reduced severity of knee OA (odds ratio (OR)=0.71 95%CI 0.56-0.91; P=0.006, I(2)=74%), and achieved borderline statistical significance in a random-effects model (OR=0.61 95%CI 0.35-1.06 P=0.08).

CONCLUSION

Common genetic variation in the Interleukin-1 region is not associated with prevalence of hip or knee OA but our data suggest that IL1RN might have a role in severity of knee OA.

Antioxidant network expression abrogates oxidative posttranslational modifications in mice

Antioxidant enzymatic pathways form a critical network that detoxifies ROS in response to myocardial stress or injury. Genetic alteration of the expression levels of individual enzymes has yielded mixed results with regard to attenuating in vivo myocardial ischemia-reperfusion injury, an extreme oxidative stress. We hypothesized that overexpression of an antioxidant network (AON) composed of SOD1, SOD3, and glutathione peroxidase (GSHPx)-1 would reduce myocardial ischemia-reperfusion injury by limiting ROS-mediated lipid peroxidation and oxidative posttranslational modification (OPTM) of proteins. Both ex vivo and in vivo myocardial ischemia models were used to evaluate the effect of AON expression. After ischemia-reperfusion injury, infarct size was significantly reduced both ex vivo and in vivo, ROS formation, measured by dihydroethidium staining, was markedly decreased, ROS-mediated lipid peroxidation, measured by malondialdehyde production, was significantly limited, and OPTM of total myocardial proteins, including fatty acid-binding protein and sarco(endo)plasmic reticulum Ca(²+)-ATPase (SERCA)2a, was markedly reduced in AON mice, which overexpress SOD1, SOD3, and GSHPx-1, compared with wild-type mice. These data demonstrate that concomitant SOD1, SOD3, and GSHPX-1 expression confers marked protection against myocardial ischemia-reperfusion injury, reducing ROS, ROS-mediated lipid peroxidation, and OPTM of critical cardiac proteins, including cardiac fatty acid-binding protein and SERCA2a.

Characterization of a novel HLA allele, HLA-B*40:128, in a Chinese individual

Nucleotide sequence of HLA-B*40:128 has a single nucleotide difference at position 539 T>G compared with that of HLA-B*40:01:01, with an amino acid change from Leu to Arg at codon 156.

Expressions of BAFF/BAFF receptors and their correlation with disease activity in Chinese SLE patients

B-cell activating factor belonging to tumour necrosis factor family (BAFF) is essential for B-cell survival and function through interaction with its receptors BAFF receptor 3 (BR3), B-cell maturation antigen (BCMA) and/or transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), though BCMA and/or TACI can also bind to a proliferation-inducing ligand (APRIL). We evaluate the correlation of the expressions of these ligands/receptors with different clinical manifestations of systemic lupus erythematosus (SLE). Levels of BAFF and APRIL in plasma from 73 SLE patients were determined by enzyme-linked immunosorbent assay. Expressions of BR3, TACI and BCMA on CD19+ B cells were detected by flow cytometry. Clinical data were collected and disease activity was evaluated using SLEDAI-2000. SLE patients had elevated BAFF and APRIL levels in their plasma. BAFF levels correlated positively with SLEDAI while negatively with the BR3 protein expression on CD19+ B cells (p < .05). The detected BR3 protein expression in SLE patients was reduced on CD19+IgD+CD27-, CD19+IgD+CD27+ as well as CD19+IgD-CD27+ B cells compared to the counterparts of healthy controls (p < .001), whereas SLE patients did not differ from healthy controls in BR3 mRNA levels. In untreated new-onset patients, the expression rate of BR3 on CD19+ B cells correlated negatively with SLEDAI (p < .05). Elevation of BAFF and reduction of BR3 on CD19+ B cells were more obvious in those with lupus nephritis (LN, p < .05). TACI expression on CD19+ B cells was up-regulated only in those subjects with LN (p < .05). Elevated plasma BAFF and reduced BR3 protein expression on peripheral B cells could act as biomarkers for active disease in SLE patients. High expression of TACI may indicate the occurrence of LN.

Transforming growth factor beta 1 plays an important role in inducing CD4(+)CD25(+)forhead box P3(+) regulatory T cells by mast cells

The role of mast cells (MCs) in the generation of adaptive immune responses especially in the transplant immune responses is far from being resolved. It is reported that mast cells are essential intermediaries in regulatory T cell (T(reg)) transplant tolerance, but the mechanism has not been clarified. To investigate whether bone marrow-derived mast cells (BMMCs) can induce T(regs) by expressing transforming growth factor beta 1 (TGF-β1) in vitro, bone marrow cells obtained from C57BL/6 (H-2(b) ) mice were cultured with interleukin (IL)-3 (10 ng/ml) and stem cell factor (SCF) (10 ng/ml) for 4 weeks. The purity of BMMCs was measured by flow cytometry. The BMMCs were then co-cultured with C57BL/6 T cells at ratios of 1:2, 1:1 and 2:1. Anti-CD3, anti-CD28 and IL-2 were administered into the co-culture system with (experiment groups) or without (control groups) TGF-β1 neutralizing antibody. The percentages of CD4(+)CD25(+)forkhead box P3 (FoxP3)(+) T(regs) in the co-cultured system were analysed by flow cytometry on day 5. The T(reg) percentages were significantly higher in all the experiment groups compared to the control groups. These changes were deduced by applying TGF-β1 neutralizing antibody into the co-culture system. Our results indicated that the CD4(+) T cells can be induced into CD4(+)CD25(+)FoxP3(+) T cells by BMMCs via TGF-β1.

A global, multicenter phase II trial of lapatinib plus capecitabine in gastric cancer

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Background: Advanced gastric cancer (GC) is an incurable disease. HER2 overexpression has been reportedin 6%–35% of gastric and gastroesophageal tumors, whereas the EGFR is upregulated in about 18%–28%. Clinical studies confirm that targeting HER2 in combination with chemotherapy is an effective strategy, achieving a median survival of ∼13.5 mos. Lapatinib, a dual tyrosine kinase inhibitor of HER2 and the EGFR, inhibits tumor growth and modulates expression of fluoropyrimidine-targeting genes. LPT109747 is an international, multicenter phase II study investigating the combination of lapatinib + capecitabine in patients with advanced gastric or gastroesophageal junction adenocarcinoma.

Methods: Primary endpoints of the study included clinical response rate, 5 mo PFS and mRNA and protein expression levels of genes involved in the 5-FU and HER2 pathway. HER2 overexpression was not required at study entry. Oral lapatinib was administered (1,250 mg/d, continuously) during a monotherapy run-in period (day -7 to 0) and in combination with oral capecitabine (1,000 mg/m2 BID, 14 of 21 days). Patients were treated until disease progression (PD) or study withdrawal. Biopsies were performed on days -7 and 0. Safety was assessed every 3 weeks and response every 6 weeks by RECIST.

Results: Sixty-seven patients were included in the current analysis: 25% female, 75% male; 51% Caucasian, 45% Asian; median age 60 y (range: 22-89 y); 75% GC, 25% GEJ. All 67 patients were evaluable for response. The overall response rate was 22.4% (16.4% confirmed). 45% of patients had stable disease, and 24% had PD. No complete responses were observed. PD or death at < 5 mo was 63%. At the time of data cut off, PFS at 5 mo was 28.4% (17.3%–40.5%); median follow up was 26.4 weeks (CI: 22.1; 55.9); 39% of patients remain in follow up. Most frequent grade 3/4 events were anemia (13%), hand-foot syndrome (12%), decreased appetite (10%), and nausea (9%).

Conclusions: The combination of lapatinib + capecitabine shows promising efficacy and is well tolerated as 1st line treatment for advanced GC. An analysis of biomarker data may help identify who may benefit most from this regimen.

[Table: see text]

Use of genetic variants in formyl peptide receptor 2 (FPR2) to predict tumor recurrence in stage II colon cancer

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Background: The formyl peptide receptor (FPR) is a G-protein-coupled receptor (GPCR) that mediates chemotaxis of phagocytic leucocytes induced by bacterial and host-derived chemotactic peptides. Recent studies found that it is selectively expressed in highly malignant gliomas and contributes to tumor growth and angiogenesis by mediating tumor cell chemotaxis, proliferation and production of chemokines and VEGF. Previously we demonstrated that polymorphisms in the VEGF pathway predict tumor recurrence in adjuvant colon cancer. Here we tested the hypothesis that two genetic variants in the FPR2 gene (rs17834679 and rs17694990) may predict tumor recurrence in a cohort of adjuvant colon cancer patients.

Methods: Between 1992 and 2007, blood samples were obtained from 234 adjuvant colon caner patients (109 with stage II and 125 with stage III) at the USC medical facilities. Genomic DNA was extracted from peripheral blood and two potentially functional genotypes (rs17834679 and rs17694990) within the FPR2 gene were determined utilizing the PCR-RFLP technique. The median follow-up was 4.4 years (range: 0.3- 16.8). Ninety of 234 patients (38.5%) developed tumor recurrence with a 3-year probability of 0.34 ± 0.05.

Results: In multivariable Cox proportional hazards regression analysis, FPR2 polymorphism rs17834679 was significantly associated with time to tumor recurrence (TTR) in stage II colon cancer (adjusted P = 0.027). Patients with CC genotype were at greatest risk of developing tumor recurrence (adjusted hazard ratio [HR]: 2.819 [95%CI: 1.127-7.051]) compared to those with GC and GG genotypes. In the dominant inheritance model, patients with any G allele had longer TTR (16.8 years+, median was not reached) compared to those with CC genotype (median TTR 5.4 years [95%CI: 3.2-10.7]; p=0.007, log-rank test). There are no significantly associations between FPR2 polymorphisms and TTR in stage III colon cancer.

Conclusions: Polymorphisms in the FPR2 gene may serve as molecular markers for tumor recurrence in stage II colon cancer, indicating that the analysis of genetic variants of FPR2 may help to identify patient subgroups at high risk for tumor recurrence.

No significant financial relationships to disclose.