Ultrastructure of medial rectus muscles in patients with intermittent exotropia

PURPOSE To study the ultrastructure of the medial rectus in patients with intermittent exotropia at different ages.PATIENTS AND METHODS The medial recti were harvested surgically from 20 patients with intermittent exotropia. Patients were divided into adolescent (age<18 years, n=10) and adult groups (age >18 years, n=10). The normal control group included five patients without strabismus and undergoing eye enucleation. Hematoxylin and eosin staining and transmission electron microscopy were used to visualize the medial recti. Western blot was used to determine the levels of myosin and actin.RESULTS Varying fiber thickness, atrophy, and misalignment of the medial recti were visualized under optical microscope in patients with exotropia. Electron microscopy revealed sarcomere destruction, myofilament disintegration, unclear dark and light bands, collagen proliferation, and fibrosis. The adolescent group manifested significantly higher levels of myosin and actin than the adult group (P<0.05).CONCLUSION Younger patients with intermittent exotropia show stronger contraction of the medial recti compared with older patients. Our findings suggest that childhood was the appropriate time for surgery as the benefit of the intervention was better than in adulthood.

Significance of detecting IgH and TCRγ gene rearrangements in patients with hemopoietic maligancies by real-time quantitative PCR

The aim of our study was to investigate the association of IgH and TCRγ gene rearrangements in hematological malignancies with the disease and clinical application. IgH and TCRγ gene rearrangements were determined in 69 paraffin and bone marrow specimens with SYBR Green I fluorescent dye and RQ-PCR method, including 21 paraffin-embedded tissues of the onset cases and 48 bone marrow samples, representing 15 ALL and 25 AML cases. After chemotherapy, 8 cases were NHL; the 10 cases of the negative control group were healthy people. Among the ALL cases, the IgH rearrangement occurred in 80.0%, the TCRγ rearrangement in 46.7%, and both gene rearrangements in 46.7%. Among the AML cases, the IgH rearrangement occurred in 72.0%, the TCRγ rearrangement in 68.0%, and both gene rearrangements in 60.0%. In the lymphoma cases, the IgH rearrangement occurred in 93.1%, the TCRγ rearrangement in 51.7%, and both gene rearrangements in 44.8%. In the negative control group, the 10 cases were all negative. There was the phenomenon of "sequence-non-fidelity" in the hematologic malignancies; the detection rate of both genes was much higher than that of the single gene. The application of the RQ-PCR method in the detection of IgH and TCRγ gene rearrangements in hematologic malignancies has important clinical significance in MRD monitoring.

Activation of the SIRT1/p66shc antiapoptosis pathway via carnosic acid-induced inhibition of miR-34a protects rats against nonalcoholic fatty liver disease

Recent studies have demonstrated that miR-34a expression is significantly upregulated and associated with apoptosis in nonalcoholic fatty liver disease (NAFLD). Carnosic acid (CA) is a novel antioxidant and a potential inhibitor of apoptosis in organ injury, including liver injury. This study aimed to investigate the signaling mechanisms underlying miR-34a expression and the antiapoptotic effect of CA in NAFLD. CA treatment significantly reduced the high-fat diet (HFD)-induced elevations in aminotransferase activity as well as in serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and malondialdehyde (MDA) levels but increased serum high-density lipoprotein cholesterol (HDL-C) and hepatic superoxide dismutase (SOD) levels. Moreover, CA treatment ameliorated the increase in cleaved caspase-3 caused by HFD exposure and completely reversed the HFD-induced decreases in manganese superoxide dismutase (MnSOD) and B-cell lymphoma-extra large expression. CA also counteracted the HFD- or palmitic acid (PA)-induced increases in caspase-3 and caspase-9 activity. Mechanistically, CA reversed the HFD- or PA-induced upregulation of miR-34a, which is the best-characterized regulator of SIRT1. Importantly, the decrease in miR-34a expression was closely associated with the activation of the SIRT1/p66shc pathway, which attenuates hepatocyte apoptosis in liver ischemia/reperfusion injury. A dual luciferase assay in L02 cells validated the modulation of SIRT1 by CA, which occurs at least partly via miR-34a. In addition, miR-34a overexpression was significantly counteracted by CA, which prevented the miR-34a-dependent repression of the SIRT1/p66shc pathway and apoptosis. Collectively, our results support a link between liver cell apoptosis and the miR-34a/SIRT1/p66shc pathway, which can be modulated by CA in NAFLD.

Two approaches for addressing electrochemical electrode arrays with reduced external connections

Although patterning hundreds or thousands of electrochemical electrodes on lab-on-a-chip devices is straightforward and cost-effective using photolithography, easily making connections between hundreds of electrodes and external amplifiers remains a bottleneck. Here we describe two electrode addressing approaches using multiple fluid compartments that can potentially reduce the number of external connections by ~100-fold. The first approach enables all compartments on the device to be filled with solution at the same time, and then each fluid compartment is sequentially electrically activated to make the measurements. The second approach achieves lower measurement noise by sequentially filling recording chambers with solution. We propose an equivalent circuit to explain measurement noise in these recording configurations and demonstrate application of the approaches to measure quantal exocytosis from individual cells. A principle advantage of using these approaches is that they reduce the fraction of the microchip area that needs to be dedicated to making external connections and therefore reduces the cost per working electrode.

Bifidobacteria Expressing Tumstatin Protein for Antitumor Therapy in Tumor-Bearing Mice

Tumstatin (Tum) is a powerful angiostatin that inhibits proliferation and induces apoptosis of tumorous vascular endothelial cells. A nonpathogenic and anaerobic bacterium, Bifidobacterium longum (BL), selectively localizes to and proliferates in the hypoxia location within solid tumor. The aims of this study were to develop a novel delivery system for Tum using engineered Bifidobacterium and to investigate the inhibitory effect of Tum on tumor in mice. A vector that enabled the expression of Tum under the control of the pBBADs promoter of BL was constructed and transformed into BL NCC2705 by electroporation. The mouse colon carcinoma cells CT26 (1 × 10(7)/mL) were subcutaneously inserted in the left armpit of BALB/c mice. The tumor-bearing mice were treated with Tum-transformed BL, and green fluorescent protein (GFP)-transformed BL was used as a negative control. The microvessel density (MVD) in the transplanted tumor was determined, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling was used to detect apoptosis of vascular endothelial cells in transplanted tumor. The in vitro expression of Tum was examined in BL after l-arabinose induction. Bifidobacterium longum with pBBAD-Tum (BL-Tum) showed significant antitumor effect in tumor-bearing mice. The weight, volume, growth, and MVD, as well as the percentage of apoptotic vascular endothelial cells of transplanted tumors in the tumor-bearing mice treated with Tum-transformed BL were all significantly lower than those in the GFP negative control group. Intragastric administration, injection in tumor and vena caudalis injection of Tum-transformed BL exerted marked antitumor effects in tumor-bearing mice. This is the first demonstration of the utilization of Tum-transformed BL as a specific gene delivery system for treating tumor.

Longitudinal assessment of oxytocin efficacy on bone and bone marrow fat masses in a rabbit osteoporosis model through 3.0-T magnetic resonance spectroscopy and micro-CT

This study aims to longitudinally assess the effect of oxytocin on bone and bone fat masses using micro-CT, in vivo magnetic resonance spectroscopy (MRS), and histopathological adipocyte quantification. Early in vivo oxytocin (OT) treatment to the osteoporosis (OP) rabbit model may reliably inhibit bone degeneration and reduce bone marrow fat accumulation by decreasing marrow adipocyte size and density.

INTRODUCTION

This study aims to longitudinally assess the effect of early OT treatment on bone and bone fat masses in a rabbit OP model by comparing the results of MRS and micro-CT with histopathological findings.

METHODS

Sixty 20-week-old female rabbits were randomly assigned into three groups. The control and OP groups were subjected to either sham surgery or bilateral ovariectomy (OVX). The OT group was subcutaneously injected with OT daily from the second week after OVX for 8 weeks. The left proximal femurs of the rabbits were evaluated through MRS, micro-CT, and histopathological examination at 0, 4, 8, 10, and 12 weeks after operation. Differences in fat fraction (FF) values, micro-CT parameters, and calculated pathological marrow adipocytes among three groups were analyzed.

RESULTS

The FF values of the OP group significantly increased (p = 0.019), but the tissue mineral density (TMD) decreased (p = 0.037) from eighth week compared with those of the control group. The FF values of the OT group significantly decreased (p = 0.044), but the TMD values increased (p = 0.042) from eighth week compared with those of the OP group. The adypocyte diameter of the OT group significantly decreased (p = 0.041) from eighth week and then adypocyte density did so too from tenth week, compared with those of the OP group at the same time point. No difference in adypocyte calculation was found between the OT and control groups until the 12th week after operation.

CONCLUSION

Early in vivo OT treatment slowed down bone deterioration and reduced bone marrow adiposity accumulation in a rabbit OP model, which is consistent with pathologic findings. OT treatment is a promising preventive OP therapy.

Circulating microRNAs in response to exercise

MicroRNAs (miRNAs, miRs) are a novel class of endogenous noncoding RNAs, which post-transcriptionally regulate gene expression via mRNA degradation or translational inhibition. miRNAs have become increasingly recognized as central players in the process of gene regulation and are responsible for a variety of essential biological processes including proliferation, differentiation and metabolism. miRNAs can be released into the circulation where they remain stable. Exercise is one of the most positive and effective means of achieving enhanced physique. This review highlights and summarizes recent progress in the field of circulating miRNAs in response to acute and chronic exercise and discusses future directions in studying circulating miRNAs in exercise-induced adaptation. A better understanding of how circulating miRNAs participate in the physiological response to exercise would eventually help develop circulating miRNAs as therapeutic targets for improving exercise capacity in patients with heart failure and other diseases.

Hole spin coherence in a Ge/Si heterostructure nanowire

Relaxation and dephasing of hole spins are measured in a gate-defined Ge/Si nanowire double quantum dot using a fast pulsed-gate method and dispersive readout. An inhomogeneous dephasing time T2* 0.18 μs exceeds corresponding measurements in III–V semiconductors by more than an order of magnitude, as expected for predominately nuclear-spin-free materials. Dephasing is observed to be exponential in time, indicating the presence of a broadband noise source, rather than Gaussian, previously seen in systems with nuclear-spin-dominated dephasing.

NF-κB and Nrf2 signaling pathways contribute to wogonin-mediated inhibition of inflammation-associated colorectal carcinogenesis

The transcriptional factors nuclear factor-κB (NF-κB) and NF-E2-related factor 2 (Nrf2) have been recently reported to have critical roles in protecting various tissues against inflammation and colitis-associated colorectal cancer (aberrant crypt foci). Our previous studies showed that wogonin (5,7-dihydroxy-8-methoxyflavone) possessed anti-neoplastic and anti-inflammatory activities. The present study extended these important earlier findings by exploring the effect of wogonin on the initiation and development of colitis-associated cancer. Wogonin lowered tumor incidence and inhibited the development of colorectal adenomas in azoxymethane- or dextran sulfate sodium-induced mice. We found that wogonin significantly decreased the secretion and expression of IL-6 and IL-1β, reduced cell proliferation and nuclear expression of NF-κB in adenomas and surrounding tissues and promoted Nrf2 nuclear translocation in surrounding tissues, although overexpressed Nrf2 in tumor tissues was independent of wogonin administration. Furthermore, wogonin inhibited the interaction between human monocytic THP-1 cells and human colon cancer HCT116 cells, and significantly downregulated lipopolysaccharide-induced secretion of prototypical pro-inflammatory cytokines IL-6 and IL-1β in THP-1 cells. Further mechanism research revealed that wogonin inhibited the nuclear translocation of NF-κB and phosphorylation of IκB and IKKα/β, and promoted Nrf2 signaling pathway in HCT116 cells and THP-1 cells. Taken together, the present results indicated that wogonin effectively suppressed inflammation-associated colon carcinogenesis and cancer development, suggesting its potential as a chemopreventive agent against colitis-associated colon cancer.

708 Common and 2010 rare DISC1 locus variants identified in 1542 subjects: analysis for association with psychiatric disorder and cognitive traits

A balanced t(1;11) translocation that transects the Disrupted in schizophrenia 1 (DISC1) gene shows genome-wide significant linkage for schizophrenia and recurrent major depressive disorder (rMDD) in a single large Scottish family, but genome-wide and exome sequencing-based association studies have not supported a role for DISC1 in psychiatric illness. To explore DISC1 in more detail, we sequenced 528 kb of the DISC1 locus in 653 cases and 889 controls. We report 2718 validated single-nucleotide polymorphisms (SNPs) of which 2010 have a minor allele frequency of <1%. Only 38% of these variants are reported in the 1000 Genomes Project European subset. This suggests that many DISC1 SNPs remain undiscovered and are essentially private. Rare coding variants identified exclusively in patients were found in likely functional protein domains. Significant region-wide association was observed between rs16856199 and rMDD (P=0.026, unadjusted P=6.3 × 10(-5), OR=3.48). This was not replicated in additional recurrent major depression samples (replication P=0.11). Combined analysis of both the original and replication set supported the original association (P=0.0058, OR=1.46). Evidence for segregation of this variant with disease in families was limited to those of rMDD individuals referred from primary care. Burden analysis for coding and non-coding variants gave nominal associations with diagnosis and measures of mood and cognition. Together, these observations are likely to generalise to other candidate genes for major mental illness and may thus provide guidelines for the design of future studies.

Selective inhibition of protein kinase C β2 attenuates the adaptor P66 Shc-mediated intestinal ischemia-reperfusion injury

Apoptosis is a major mode of cell death occurring during ischemia–reperfusion (I/R) induced injury. The p66^Shc adaptor protein, which is mediated by PKCβ, has an essential role in apoptosis under oxidative stress. This study aimed to investigate the role of PKCβ₂/p66^Shc pathway in intestinal I/R injury. In vivo, ischemia was induced by superior mesenteric artery occlusion in mice. Ruboxistaurin (PKCβ inhibitor) or normal saline was administered before ischemia. Then blood and gut tissues were collected after reperfusion for various measurements. In vitro, Caco-2 cells were challenged with hypoxia–reoxygenation (H/R) to simulate intestinal I/R. Translocation and activation of PKCβ₂ were markedly induced in the I/R intestine. Ruboxistaurin significantly attenuated gut damage and decreased the serum levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Pharmacological blockade of PKCβ₂ suppressed p66^Shc overexpression and phosphorylation in the I/R intestine. Gene knockdown of PKCβ₂ via small interfering RNA (siRNA) inhibited H/R-induced p66^Shc overexpression and phosphorylation in Caco-2 cells. Phorbol 12-myristate 13-acetate (PMA), which stimulates PKCs, induced p66^Shc phosphorylation and this was inhibited by ruboxistaurin and PKCβ₂ siRNA. Ruboxistaurin attenuated gut oxidative stress after I/R by suppressing the decreased expression of manganese superoxide dismutase (MnSOD), the exhaustion of the glutathione (GSH) system, and the overproduction of malondialdehyde (MDA). As a consequence, ruboxistaurin inhibited intestinal mucosa apoptosis after I/R. Therefore, PKCβ₂ inhibition protects mice from gut I/R injury by suppressing the adaptor p66^Shc-mediated oxidative stress and subsequent apoptosis. This may represent a novel therapeutic approach for the prevention of intestinal I/R injury.

Comparing drug detection in oral fluid and blood: data from a national sample of nighttime drivers

OBJECTIVE

The National Roadside Survey is a study undertaken in the United States to determine the prevalence of alcohol and drugs in randomly selected drivers. Following the success of a 2006 pilot study, the 2007 survey incorporated, for the first time, the collection of biological specimens for drug analysis. This article compares the results obtained from blinded analyses of pairs of oral fluid and blood samples obtained from the same subject.

METHODS

During the 2007 survey, more than 7000 nighttime drivers were randomly stopped and surveyed for their self-reported drug use and were requested to donate an oral fluid specimen using the Quantisal (Immunalysis Corporation, Pomona, CA) device and a blood sample. Overall, 5869 oral fluid specimens were collected from nighttime drivers with 3236 corresponding blood samples.

RESULTS

Biological specimens were analyzed for a wide range of drugs. At nighttime, 14.4 percent of the drivers were positive for drugs in oral fluid, with just over half of those having marijuana present (7.6%). Of the 3236 pairs of specimens, 2676 were negative for all drugs, and 326 matched pairs of samples were both positive, out of which 247 (75.8%) were an exact match for all drug classes and 70 (21.5%) were positive for at least one common drug class.

CONCLUSIONS

Oral fluid and blood samples provided very similar information regarding recent drug intake by randomly tested drivers and oral fluid yielded a higher detection rate for one drug (cocaine) than blood. Oral fluid can be considered a reliable alternative to blood as a matrix for drug testing.

The nature and origin of nucleus-like intracellular inclusions in Paleoproterozoic eukaryote microfossils

The well-known debate on the nature and origin of intracellular inclusions (ICIs) in silicified microfossils from the early Neoproterozoic Bitter Springs Formation has recently been revived by reports of possible fossilized nuclei in phosphatized animal embryo-like fossils from the Ediacaran Doushantuo Formation of South China. The revisitation of this discussion prompted a critical and comprehensive investigation of ICIs in some of the oldest indisputable eukaryote microfossils-the ornamented acritarchs Dictyosphaera delicata and Shuiyousphaeridium macroreticulatum from the Paleoproterozoic Ruyang Group of North China-using a suite of characterization approaches: scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focused ion beam scanning electron microscopy (FIB-SEM). Although the Ruyang acritarchs must have had nuclei when alive, our data suggest that their ICIs represent neither fossilized nuclei nor taphonomically condensed cytoplasm. We instead propose that these ICIs likely represent biologically contracted and consolidated eukaryotic protoplasts (the combination of the nucleus, surrounding cytoplasm, and plasma membrane). As opposed to degradational contraction of prokaryotic cells within a mucoidal sheath-a model proposed to explain the Bitter Springs ICIs-our model implies that protoplast condensation in the Ruyang acritarchs was an in vivo biologically programmed response to adverse conditions in preparation for encystment. While the discovery of bona fide nuclei in Paleoproterozoic acritarchs would be a substantial landmark in our understanding of eukaryote evolution, the various processes (such as degradational and biological condensation of protoplasts) capable of producing nuclei-mimicking structures require that interpretation of ICIs as fossilized nuclei be based on comprehensive investigations.

Lack of mutations of G4.5 in three families from China with noncompaction of the ventricular myocardium

To find the underlying cause of noncompaction of the ventricular myocardium (NVM), three Chinese families with probands who presented this problem were studied. After the family members were evaluated by echocardiography, the gene G4.5 (taffazin) was scanned by sequencing. Although X-linked inheritance could not be ruled out, NVM were thought to have a vague rule of inheritance in our data from 8 patients and 28 family members. We also did not identify any mutations in G4.5 in all samples. Our data suggest that other genes are responsible for the familial form of this disease.

Correlation of subclinical HPV infection with genital warts and cervical erosion

OBJECTIVE

To investigate the correlation of subclinical human papillomavirus (HPV) infection (SPI) with genital warts and cervical erosion.

MATERIALS AND METHODS

The questionnaire was firstly conducted in experimental groups (genital warts + cervical erosion), and then cervical liquid-based cytology was performed, followed by colposcopy and pathological diagnosis. In the control group, cervical liquid-based cytology and pathological diagnosis were performed. Hybrid Capture 2 assay (HC2) was conducted to detect the cervical high-risk HPV DNA.

RESULTS

The positive rate of cervical SPI in experimental groups were significantly higher than control group (p < 0.01), and in the genital warts group it was significantly higher than cervical erosion group (p < 0.05). There was no significant difference of SPI positive rate for cervical erosion with different area and degree (p > 0.05). Compared to control group, the detection rates of cervical high-risk HPV DNA in the experimental groups significantly increased (p < 0.01), and the difference between vulvar condyloma and cervical erosion groups was not statistically significant (p < 0.05). The detection rate of high-risk HPV DNA in positive SPI cases was significantly higher than negative SPI cases.

CONCLUSIONS

Women with genital warts and cervical erosion are high-risk individuals for cervical cancer, and deserve a focused initial and follow-up management.

Point mutation of the c-Ki-ras proto-oncogene and the p53 tumour suppressor gene in distal colonic adenocarcinomas

One hundred and twenty-seven monochronous primary colorectal adenocarcinomas were examined for both activation of the c-Ki-ras proto-oncogene by point mutation in codons 12 or 13 and inactivation of the p53 tumour suppressor gene by point mutation in exons four through nine. All of the carcinomas originated in the distal half of the colorectum. Activation of the c-Ki-ras proto-oncogene was detected in 23% (29/127) of adenocarcinomas, and p53 inactivation was detected in 63% (80/127) of adenocarcinomas. Only 16% (20/127) of cases exhibited both genetic changes, and no association was noted between the occurrence of these two changes. Individually, both ras activation and p53 inactivation were associated with a poorer patient prognosis (p=0.0009 and p=0.0159 respectively). In a Cox regression analysis both ras activation and p53 inactivation contributed independently towards patient mortality. These results suggest that mutations exert their effect independently of each other, and that it is the cumulative mutational load that determines a patient's prognosis.

Clinical Analysis of 50 Chinese Patients with Aqueous Misdirection Syndrome: A Retrospective Hospital-Based Study

OBJECTIVES: To evaluate the efficacy of treatments for aqueous misdirection syndrome and explore possible risk factors influencing prognosis. METHODS: Data including demographics, initial clinical characteristics and ocular outcomes at follow-up were collected for patients treated for aqueous misdirection syndrome. Main outcome measures were: best-corrected visual acuity (BCVA); intraocular pressure (IOP); number of antiglaucoma medications; recurrence; complications. RESULTS: Data were available for 50 patients (57 eyes). Final mean BCVA improved significantly and correlated with baseline BCVA (mean follow-up, 34.47 ± 28.65 months). Final mean IOP and mean number of antiglaucoma medications were significantly reduced. Treatment failure rates were higher in patients with significantly higher IOP at baseline and/or shorter axial length. Following pars plana vitrectomy (PPV), recurrence occurred in two of 10 pseudophakic and one of 40 phakic eyes; complications were observed in 12/50 eyes (choroidal detachment, corneal decompensation, retinal detachment, vitreous haemorrhage, hyphaema). CONCLUSIONS: PPV and laser treatments, augmented by pharmacotherapy, were effective in treating aqueous misdirection syndrome. Surgical intervention should be undertaken early in eyes with higher baseline IOP and/or shorter axial length. Total vitrectomy— zonulectomy—iridectomy is a potential approach for recalcitrant cases.

Cordycepin as a sensitizer to tumour necrosis factor (TNF)-α-induced apoptosis through eukaryotic translation initiation factor 2α (eIF2α)- and mammalian target of rapamycin complex 1 (mTORC1)-mediated inhibition of nuclear factor (NF)-κB

Cordycepin (3'-deoxyadenosine) is one of the major bioactive substances produced by Cordyceps militaris, a traditional medicinal mushroom. Cordycepin possesses several biological activities, including both pro-apoptotic and anti-apoptotic properties. In the present report, we investigated an effect of cordycepin on the survival of cells exposed to tumour necrosis factor (TNF)-α. We found that subtoxic doses of cordycepin increased susceptibility of cells to TNF-α-induced apoptosis. It was associated with suppression of nuclear factor-κB (NF-κB), a major prosurvival component involved in TNF-α signalling. The adenosine transporter and A₃ adenosine receptor, but not A₁ and A₂ adenosine receptors, mediated both anti-NF-κB and pro-apoptotic effects. We found that cordycepin had the potential to phosphorylate eukaryotic translation initiation factor 2α (eIF2α) and that activation of eIF2α mimicked the suppressive effect of cordycepin on the NF-κB pathway. Furthermore, activation of eIF2α sensitized cells to TNF-α-induced apoptosis. To identify molecular events downstream of eIF2α, the role of mammalian target of rapamycin complex 1 (mTORC1) was examined. Selective activation of ₃eIF2α, as well as treatment with cordycepin, caused phosphorylation of mTORC1. Rapamycin, an inhibitor of mTORC1, significantly reversed the suppressive effects of eIF2α on NF-κB. These results suggest that cordycepin sensitizes cells to TNF-α-induced apoptosis, at least in part, via induction of the eIF2α-mTORC1 pathway and consequent suppression of NF-κB.

Chronic treatment with a glucokinase activator delays the onset of hyperglycaemia and preserves beta cell mass in the Zucker diabetic fatty rat

AIMS/HYPOTHESIS

Glucokinase activators (GKAs) are currently being developed as new therapies for type 2 diabetes and have been shown to enhance beta cell survival and proliferation in vitro. Here, we report the effects of chronic GKA treatment on the development of hyperglycaemia and beta cell loss in the male Zucker diabetic fatty (ZDF) rat, a model of type 2 diabetes with severe obesity.

METHODS

Cell protection by GKA was studied in MIN6 and INS-1 cells exposed to hydrogen peroxide. Glucose homeostasis and beta cell mass were evaluated in ZDF rats dosed for 41 days with Cpd-C (a GKA) or glipizide (a sulfonylurea) as food admixtures at doses of approximately 3 and 10 mg kg(-1) day(-1).

RESULTS

Incubation of MIN6 and INS-1 832/3 insulinoma cell cultures with GKA significantly reduced cell death and impairment of intracellular NADH production caused by exposure to hydrogen peroxide. Progression from prediabetes (normoglycaemia and hyperinsulinaemia) to overt diabetes (hyperglycaemia and hypoinsulinaemia) was significantly delayed in male ZDF rats by in-feed treatment with Cpd-C, but not glipizide. Glucose tolerance, tested in the fifth week of treatment, was also significantly improved by Cpd-C, as was pancreatic insulin content and beta cell area. In a limited immunohistochemical analysis, Cpd-C modestly and significantly enhanced the rate of beta cell proliferation, but not rates of beta cell apoptosis relative to untreated ZDF rats.

CONCLUSIONS/INTERPRETATION

These findings suggest that chronic activation of glucokinase preserves beta cell mass and delays disease in the ZDF rat, a model of insulin resistance and progressive beta cell failure.

Quantitative assessment of first-pass perfusion using a low-dose method at multidetector CT in oesophageal squamous cell carcinoma: correlation with VEGF expression

AIM

To investigate the correlation between vascular endothelial cell growth factor (VEGF) expression and first-pass perfusion parameters at multidetector computed tomography (MDCT) using a low-dose technique, and to determine how to discriminate VEGF positivity from VEGF negativity by perfusion CT in oesophageal squamous cell carcinomas.

MATERIALS AND METHODS

Thirty-two patients with oesophageal squamous cell carcinomas underwent first-pass perfusion with 64-section MDCT at 50 mAs. Perfusion parameters, including perfusion, peak enhanced density (PED), time to peak (TTP), and blood volume (BV), were measured. Postoperative specimens were assessed for VEGF expression. Correlation tests were performed to determine the associations between each CT perfusion parameter and VEGF expression. The cut-off values of perfusion parameters were obtained statistically to discriminate VEGF positivity from VEGF negativity.

RESULTS

Mean perfusion, PED, TTP, and BV were 38.47 ± 30.26 ml/min/ml, 24.68 ± 9.65 HU, 28.35 ± 9.03 s, and 11.82 ± 6.06 ml/100 g, respectively. PED or BV were significantly higher in the VEGF-positive group than in the VEGF-negative group (all p < 0.05), but no significant difference in perfusion or TTP was found between the VEGF-positive and VEGF-negative groups (all p > 0.05). In VEGF positivity, PED and BV were correlated with VEGF expression (r = 0.576 and 0.765, respectively; all p < 0.05), whereas perfusion and TTP were not (r = 0.361 and 0.239, respectively; all p > 0.05). A threshold of BV (10.23 ml/100 g) achieved a sensitivity of 94.4%, and a specificity of 92.9% for discriminating VEGF positivity from VEGF negativity.

CONCLUSION

BV could reflect tumour VEGF expression, and could be an indicator for evaluating angiogenesis in oesophageal tumours.