Mechanisms for multiple resistances in field populations of rice stem borer, Chilo suppressalis (Lepidoptera: Crambidae) from Sichuan Province, China.

Chilo suppressalis Walker (Lepidoptera: Crambidae) is a widely destructive pest occurring in rice, particularly in the rice-growing regions of Asia. In recent years, C. suppressalis has developed resistance to several insecticides because of the extensive use of insecticides. The resistance levels to four insecticides were determined among populations from different regions of Sichuan Province, China, using a drop-method bioassay. Based on LC50 values of a laboratory susceptible strain, all field populations showed moderate level of resistance to triazophos (23.9- to 83.5-fold) and were either susceptible or had a low level of resistance to abamectin (2.1- to 5.8-fold). All field-collected populations had a low or moderate level of resistance to chlorpyrifos (1.7- to 47.1-fold) and monosultap (2.7- to 13.5-fold). The synergism experiment indicated that the resistance of the XW19 to triazophos may be associated with cytochrome P450 monooxygenases (P450s), with the highest synergistic ratio (SR) of 3.05-fold and increased ratio (IR) of 2.28-fold for piperonylbutoxide (PBO). The P450 activity of the TJ19 population was the greatest among the six field populations. Moreover, the relative expression levels of four resistance-related P450 genes were detected with qRT-PCR, and the results indicated that CYP324A12, CYP321F3 and CYP9A68 were overexpressed in the resistant population, especially in the XW19 population (by 1.2-, 3.4 -, and 18.0-fold, respectively). In addition, the relative expression levels of CYP9A68 among the CZ19 and TJ19 populations were also enhanced 10.5- and 24.9-fold, respectively. These results suggested that CYP324A12, CYP321F3 and CYP9A68 may be related to the resistance development of C. suppressalis to triazophos.

Norcrassin A, a novel C16 tetranorditerpenoid, and bicrotonol A, an unusual dimeric labdane-type diterpenoid, from the roots of Croton crassifolius.

A novel C16 tetranorditerpenoid, norcrassin A (1), and an unusual dimeric labdane-type diterpenoid, bicrotonol A (2), were isolated from the roots of Croton crassifolius. Norcrassin A (1) featured a new carbon skeleton with an unprecedented 5/5/5/6 tetracyclic system. Bicrotonol A (2) possessed an unusual tetrahydroxypyran ring linkage connecting two labdane diterpenoid monomers. The structures of all compounds, including the absolute configuration, were elucidated by the interpretation of their NMR spectroscopic data, high resolution mass spectrometry, and single-crystal X-ray diffraction. A plausible biosynthetic pathway of 1 is proposed. The anti-Alzheimer's Disease (AD) activities of 1 and 2 are also evaluated using the AD pathological model.

Cotesia ruficrus (Hymenoptera: Braconidae) Parasitizing Cnaphalocrocis medinalis (Lepidoptera: Pyralidae): Developmental Interactions and Food Utilization Efficiency of Hosts.

Cotesia ruficrus (Haliday), a gregarious larval endoparasitoid, is an important biological control agent of various pest species. The developmental interactions between the host rice leaf folder, Cnaphalocrocis medinalis (Guenée), and its koinobiont parasitoid, C. ruficrus, were investigated for the first time under laboratory conditions. The effects of host instar at parasitization on the development time, clutch size, and survival of C. ruficrus were determined. The results showed that the parasitoids starting parasitism in the fourth-instar larvae had the shortest development duration and highest fecundity. Meanwhile, the growth of the host parasitized by C. ruficrus in various instars was also observed. The results indicated that the growth of the parasitized larvae was significantly inhibited, compared with unparasitized ones, irrespective of the host instar at oviposition. In addition, the effect of parasitism on food consumption and utilization of the fourth-instar larvae was determined, suggesting that the nutritional physiology of the host was affected by parasitism. Wet or dry weight gain, food consumption, and fecal matter were all significantly reduced in the parasitized larvae in contrast with the unparasitized larvae. Parasitization by C. ruficrus could significantly increase the approximate digestibility of the host.

Functional and structural alterations of peritoneum and secretion of fibrotic cytokines in rats caused by high glucose peritoneal dialysis solutions.

OBJECTIVE: To determine functional and structural alterations of peritoneum and fibrotic cytokines expression in peritoneal dialysis (PD) rats. METHODS: 28 Sprague-Dawley (S-D) rats were randomly divided into four groups and dialyzed with various solutions daily for four weeks: (1) no solution (CON group), (2) 0.9% Saline solution (NS group), (3) 1.5% Dianeal (LG group), (4) 4.25% Dianeal (HG group). Peritoneal equilibration tests, ultrafiltration function and effluent protein quantification were measured. Peritoneum morphology was studied and immunohistochemistry were performed for detection of transforming growth factor ß1 (TGF-ß1), connective tissue growth factor (CTGF), and fibronectin (FN) proteins. Reverse transcriptional-polymerase chain reaction was used to analyze the expression of TGF-ß1, CTGF mRNA. RESULTS: Administration of 4.25% Dianeal caused functional and structural changes of peritoneum, including protein loss through the transport process, decrease of peritoneal solute transport rate and ultrafiltration capacity. The collagen of peritoneum in the HG group was thicker than the other groups. The levels of CTGF, TGF-ß1, and FN proteins were significantly the highest in the HG group, followed by the LG group. The liner correlation analysis showed positive correlations between the levels of CTGF, TGF-ß1, and FN proteins and the collagen thickness. The expression of TGF-ß1 and CTGF mRNA in the HG group were significantly higher than those in the other groups and were indicated positive correlation. CONCLUSION: Using high glucose peritoneal dialysis solutions in rats may not only lead to processing of peritoneal fibrosis, which is promoted by ectopic expression of TGF-ß1, but also increase the expression of CTGF. CTGF is an important fibrotic media of peritoneal fibrosis in PD rats.

Effects of juvenile hormone analogue and ecdysteroid on adult eclosion of the fruit fly Bactrocera minax (Diptera: Tephritidae).

The univoltine Bactrocera minax (Enderlein) is a devastating pest of citrus in Nepal, India, Bhutan, and China. To better understand the overwintering pupal diapause, we investigated the juvenile hormone III (JH III) and ecdysteroid 20-hydroxyecdysone (20E) titers across the developmental stages, and the effects of juvenile hormone analog (JHA) and 20E treatments on adult emergence patterns. The results showed that both JH III and 20E levels fluctuated from the late larval stage to the late pupal stage. JHA and 20E treatments at the late larval stage had marginal effect on the adult emergence patterns, with slightly faster adult eclosion and higher eclosion rate. Similarly, JHA treatment at the early pupal stage did not affect the adult emergence. However, 20E treatment at the early pupal stage remarkably shortened the duration of diapause, but lowered the eclosion rate, especially with relatively high dose. These findings demonstrated that 20E treatment at the early pupal stage is a suitable method to hasten the diapause termination of B. minax, which will contribute to the rearing of B. minax in the laboratory as needed for routine experiments.

HSP47 regulates ECM accumulation in renal proximal tubular cells induced by TGF-ß1 through ERK1/2 and JNK MAPK pathways.

Heat shock protein (HSP)47 is a collagen-specific molecular chaperone that is essential for the biosynthesis of collagen molecules. It is likely that increased levels of HSP47 contribute to the assembly of procollagen and thereby cause an excessive accumulation of collagens in disease processes associated with fibrosis. Although HSP47 promotes renal fibrosis, the underlying mechanism and associated signaling events have not been clearly delineated. We examined the role of HSP47 in renal fibrosis using a rat unilateral ureteral obstruction model and transforming growth factor (TGF)-ß(1)-treated human proximal tubular epithelial (HK-2) cells. An upregulation of HSP47 in both in vivo and in vitro models was observed, which correlated with the increased synthesis of extracellular matrix (ECM) proteins and expression of tissue-type plasminogen activator inhibitor (PAI)-1. Blockade of HSP47 by short interfering RNA suppressed the expression of ECM proteins and PAI-1. In addition, TGF-ß(1)-induced HSP47 expression in HK-2 cells was attenuated by ERK1/2 and JNK MAPK inhibitors. These data suggest that ERK1/2 and JNK signaling events are involved in modulating the expression of HSP47, the chaperoning effect of which on TGF-ß(1) would ultimately contribute to renal fibrosis by enhancing the synthesis and deposition of ECM proteins.

miRNA589 regulates epithelial-mesenchymal transition in human peritoneal mesothelial cells.

Background. microRNA (miRNA, miR) are thought to interact with multiple mRNAs which are involved in the EMT process. But the role of miRNAs in peritoneal fibrosis has remained unknown. Objective. To determine if miRNA589 regulates the EMT induced by TGFß1 in human peritoneal mesothelial cell line (HMrSV5 cells). Methods. 1. Level of miR589 was detected in both human peritoneal mesothelial cells (HPMCs) isolated from continuous ambulatory peritoneal dialysis (CAPD) patients' effluent and HMrSV5 cells treated with or without TGFß1. 2. HMrSV5 cells were divided into three groups: control group, TGFß1 group, and pre-miR-589+TGFß1 group. The level of miRNA589 was determined by realtime PCR. The expressions of ZO-1, vimentin, and E-cadherin in HPMCs were detected, respectively. Results. Decreased level of miRNA589 was obtained in either HPMCs of long-term CAPD patients or HMrSV5 cells treated with TGFß1. In vitro, TGFß1 led to upregulation of vimentin and downregulation of ZO-1 as well as E-cadherin in HMrSV5 cells, which suggested EMT, was induced. The changes were accompanied with notably decreased level of miRNA589 in HMrSV5 cells treated with TGFß1. Overexpression of miRNA589 by transfection with pre-miRNA589 partially reversed these EMT changes. Conclusion. miRNA589 mediates TGFß1 induced EMT in human peritoneal mesothelial cells.

Evaluation of renal clinicopathological changes in IgA nephropathy by urinary podocytes excretion and podocalyxin expression.

OBJECTIVE: To explore the association of urinary podocyte excretion and renal expression of podocyte-specific marker podocalyxin (PCX) with clinicopathological changes in immunoglobulin A nephropathy (IgAN). METHODS: Morning urine samples from IgAN patients and healthy controls were collected. The expression of glomerular PCX was quantified in 50 IgAN patients diagnosed by renal biopsy. IgAN was classified based on the Lee's Grading system and scored according to the Katafuchi semiquantitative criteria. Morphological evaluation of podocyte was determined by electron microscopy. RESULTS: The amount of urinary podocytes in the IgAN patients was significantly higher than that in the healthy controls (p < 0.01). Pairwise comparison among Lee's grades of IgAN showed that the median of urinary podocytes in Lee's I-II group was lower than that in Lee's III, IV, and V groups (p < 0.05); group III lower than group V (p < 0.05). The positive rate of urinary podocytes was the highest in Lee's IV and V groups (100%), and lowest in Lee's I-II group (55%). Multiple comparison among groups of Lee's grades of IgAN showed that the glomerular PCX expression in Lee's I-II group was higher than that in Lee's III, IV, and V groups (p < 0.05); groups III and IV higher than group V (p < 0.05). The amount of urinary podocytes in IgAN patients was negatively correlated with PCX expression (r = -0.702, p < 0.01), but positively correlated with 24-h urinary protein (r = 0.465, p < 0.01) and glomerular (r = 0.233, p < 0.01) and renal tubular pathological scores (r = 0.307, p < 0.05). The glomerular PCX expression was negatively correlated with 24-h urinary protein (r = -0.367, p < 0.05) and glomerular (r = -0.560, p < 0.05) and tubular pathological scores (r = -0.377, p < 0.05). Electron microscopy showed significant changes in podocytes of IgAN, especially in the foot process. CONCLUSION: The amount of urinary podocyte can reflect the loss of podocytes in renal tissue, which may be a marker of IgAN progression.

Trehalose-6-phosphate phosphatases are involved in trehalose synthesis and metamorphosis in Bactrocera minax.

Trehalose is the principal sugar circulating in the hemolymph of insects, and trehalose synthesis is catalyzed by trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP). Insect TPS is a fused enzyme containing both TPS domain and TPP domain. Thus, many insects do not possess TPP genes as TPSs have replaced the function of TPPs. However, TPPs are widely distributed across the dipteran insects, while the roles they play remain largely unknown. In this study, 3 TPP genes from notorious dipteran pest Bactrocera minax (BmiTPPB, BmiTPPC1, and BmiTPPC2) were identified and characterized. The different temporal-spatial expression patterns of 3 BmiTPPs implied that they exert different functions in B. minax. Recombinant BmiTPPs were heterologously expressed in yeast cells, and all purified proteins exhibited enzymatic activities, despite the remarkable disparity in performance between BmiTPPB and BmiTPPCs. RNA interference revealed that all BmiTPPs were successfully downregulated after double-stranded RNA injection, leading to decreased trehalose content and increased glucose content. Also, suppression of BmiTPPs significantly affected expression of downstream genes and increased the mortality and malformation rate. Collectively, these results indicated that all 3 BmiTPPs in B. minax are involved in trehalose synthesis and metamorphosis. Thus, these genes could be evaluated as insecticidal targets for managing B. minax, and even for other dipteran pests.

Toxicity Effects and Mechanisms of MgO Nanoparticles on the Oomycete Pathogen Phytophthora infestans and Its Host Solanum tuberosum.

Engineered nanoparticles have recently been used for innovation in agricultural disease management. However, both the toxicity effects and mechanisms of nanoparticles in target pathogens and their host plants are still largely unknown. Here, we found that magnesium oxide nanoparticles (MgO NPs) could protect potatoes against Phytophthora infestans (P. infestans) at a low dosage (50 µg/mL). Through scanning electron microscopy observation, antioxidant enzymes activity measurement, and gene transcriptome analysis, we found that the cell surfaces of P. infestans were destroyed, endogenous superoxide dismutase continuously remained in a higher active state, oxidoreductase activity-related gene ontology (GO) terms were enriched with upregulation, and transporter-activity related GO terms and six essential metabolism-related pathways were enriched with downregulation in P. infestans after 30 min MgO NPs treatment, whereas only 89 genes were changed without enriched GO and pathways terms, and no change in antioxidant activities and phenylalnine ammonialyase in potato appeared at 6 h post-MgO NPs treatment. Only the "plant hormone signal transduction pathway" was enriched with upregulation under differential expression analysis in potatoes. In conclusion, cell surface distortion, continuous oxidative stress, and inhibitions of membrane transport activity and metabolic pathways were toxic mechanisms of Mg ONPs in P. infestans, and the "plant hormone signal transduction pathway" was potentially regulated by Mg-ONPs without obviously harmful effects on potato after Mg ONPs exposure.

Long-term nucleos(t)ide analogues therapy for adults with chronic hepatitis B reduces the risk of long-term complications: a meta-analysis.

BACKGROUND: The effect of antiviral therapy in chronic hepatitis B (CHB) on reducing the risk of long-term complications (LTCs) remains unclear so far. To study whether long-term nucleos(t)ide analogues therapy can reduce the risk of long-term complications. METHODS: We searched MEDLINE, EMBASE, OVID, the Cochrane Central Register of Controlled Trials. Relative risks (RRs) of long-term complications with or without treatment were studied. Also subgroup analyses including the status of drug-resistance, HBeAg and pre-existing compensated cirrhosis were done using relative risks of long-term complications either with or without treatment or among nucleos(t)ide analogues treatment groups. RESULTS: Six eligible studies (3644 patients in all) were included. Data showed the incidence of long-term complications in treatment groups was induced by 74%(RR:0.26, 95% CI: 0.15-0.47) compared with no treatment. Whether drug-resistant happened or not during the long-term therapy, the incidence of long-term complications was still significantly induced respectively by 45%(RR: 0.55,95%CI:0.40-0.76) and 78% (RR:0.22, 95%CI: 0.13-0.36). For both different status of HBeAg and pre-existing compensated cirrhosis, there was significant lower incidence of long-term complications in treatment groups compared with no treatment, too. Moreover, among the NA treatment groups, patients with drug-resistance had 2.64 times (RR:2.64, 95%CI: 1.58-4.41) higher chance of developing to long-term complications, and patients with pre-existing compensated cirrhosis also had 3.07 times (RR:3.07, 95%CI: 1.04-9.11) higher chance of developing to long-term complications. CONCLUSIONS: Long-term nucleos(t)ide analogue therapy for adults with CHB prevents or delays the development of long-term complications including decompensated cirrhosis, CHB-related death or CHB-related HCC in patients with CHB. The patients who need take antiviral drugs should receive the antiviral therapy as soon as possible.

The complete mitogenome of Chlorops oryzae Matsumura (Diptera: Chloropidae).

Chlorops oryzae Matsumura is an important pest of rice plants throughout Asia, and has even become a major pest in some regions. Here, we present the complete mitogenome of C. oryzae for the first time. The complete mitogenome is 17,313 bp in length and contains 37 genes (13 protein-coding genes, 22 transfer RNAs, and two ribosomal RNAs) and a control region. The overall base composition is 42.04% for A, 37.18% for T, 12.59% for C, and 8.29% for G, with a bias toward A + T (79.22%). Protein-coding genes cox1 features an atypical ACG start codon and cox2, nad5, and nad4 have incomplete stop codons T or TA. All tRNA genes present the typical clover leaf secondary structure except trnS1 (AGN), where the DHU arm is replaced by a loop. Phylogeny showed that C. oryzae was placed as the basal lineage in Brachycera clade, and shared a closer relationship to Acalyptrate species.

p66Shc mediates high-glucose and angiotensin II-induced oxidative stress renal tubular injury via mitochondrial-dependent apoptotic pathway.

p66Shc, a promoter of apoptosis, modulates oxidative stress response and cellular survival, but its role in the progression of diabetic nephropathy is relatively unknown. In this study, mechanisms by which p66Shc modulates high-glucose (HG)- or angiotensin (ANG) II-induced mitochondrial dysfunction were investigated in renal proximal tubular cells (HK-2 cells). Expression of p66Shc and its phosphorylated form (p-p66Shc, serine residue 36) and apoptosis were notably increased in renal tubules of diabetic mice, suggesting an increased reactive oxygen species production. In vitro, HG and ANG II led to an increased expression of total and p-p66Shc in HK-2 cells. These changes were accompanied with increased production of mitochondrial H(2)O(2), reduced mitochondrial membrane potential, increased translocation of mitochondrial cytochrome c from mitochondria into cytosol, upregulation of the expression of caspase-9, and ultimately reduced cell survival. Overexpression of a dominant-negative Ser36 mutant p66Shc (p66ShcS36A) or treatment of p66Shc- or PKC-ß-short interfering RNAs partially reversed these changes. Treatment of HK-2 cells with HG and ANG II also increased the protein-protein association between p-p66Shc and Pin1, an isomerase, in the cytosol, and with cytochrome c in the mitochondria. These interactions were partially disrupted with the treatment of PKC-ß inhibitor or Pin1-short interfering RNA. These data suggest that p66Shc mediates HG- and ANG II-induced mitochondrial dysfunctions via PKC-ß and Pin1-dependent pathways in renal tubular cells.

Comparative proteomics provides insights into diapause program of Bactrocera minax (Diptera: Tephritidae).

The Chinese citrus fly, Bactrocera minax, is a notorious univoltine pest that causes damage to citrus. B. minax enters obligatory pupal diapause in each generation to resist harsh environmental conditions in winter. Despite the enormous efforts that have been made in the past decade, the understanding of pupal diapause of B. minax is currently still fragmentary. In this study, the 20-hydroxyecdysone solution and ethanol solvent was injected into newly-formed pupae to obtain non-diapause- (ND) and diapause-destined (D) pupae, respectively, and a comparative proteomics analysis between ND and D pupae was performed 1 and 15 d after injection. A total of 3,255 proteins were identified, of which 190 and 463 were found to be differentially abundant proteins (DAPs) in ND1 vs D1 and ND15 vs D15 comparisons, respectively. The reliability and accuracy of LFQ method was validated by qRT-PCR. Functional analyses of DAPs, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and protein-protein interaction (PPI) network construction, were conducted. The results revealed that the diapause program of B. minax is closely associated with several physiological activities, such as phosphorylation, chitin biosynthesis, autophagy, signaling pathways, endocytosis, skeletal muscle formation, protein metabolism, and core metabolic pathways of carbohydrate, amino acid, and lipid conversion. The findings of this study provide insights into diapause program of B. minax and lay a basis for further investigation into its underlying molecular mechanisms.

Cadinane-type sesquiterpenes from the resinous exudates of Commiphora myrrha and their anti-Alzheimer's disease bioactivities.

Commiphoins A-C (1-3), three new cadinane-type sesquiterpenes, together with two known cadinane-type sesquiterpenes (4 and 5) were isolated from the resinous exudates of Commiphora myrrha. Their structures and relative configurations were established on the basis of comprehensive spectroscopic methods, including HRESIMS, 1D and 2D NMR analyses. Compounds 1 and 3-5 were screened for anti-Alzheimer's disease (AD) activities using the AD pathological model in Caenorhabditis elegans. The results showed that they all had significant anti-AD activities.

Expression Analysis Reveals the Association of Several Genes with Pupal Diapause in Bactrocera minax (Diptera: Tephritidae).

The Chinese citrus fly, Bactrocera minax, is a devastating pest of citrus, which enters the obligatory diapause in overwintering pupae to resist harsh environmental conditions. However, little is known about the molecular mechanisms underlying pupal diapause. The previous transcriptomic analysis revealed that a large number of genes were regulated throughout the pupal stage. Of these genes, 12 and six ones that are remarkably up- and downregulated, respectively, specifically in intense diapause were manually screened out in present study. To validate the expression of these genes throughout the pupal stage, the quantitative real-time PCR (qRT-PCR) was conducted, and the genes displaying different expression patterns with those of previous study were excluded. Then, the expressions of remaining genes were compared between diapause-destined and non-diapause-destined pupae to reveal their association with diapause using qRT-PCR and semiquantitative PCR. Finally, five genes, TTLL3B, Cyp6a9, MSTA, Fru, and UC2, and two genes, KSPI and LYZ1, were demonstrated to be positively and negatively associated with diapause, respectively. These findings provide a solid foundation for the further investigation of molecular mechanisms underlying B. minax pupal diapause.

Norcantharidin ameliorates proteinuria, associated tubulointerstitial inflammation and fibrosis in protein overload nephropathy.

Norcantharidin (NCTD), the demethylated analog of cantharidin isolated from Mylabris, is an anticancer drug routinely used against various human cancers in China. The aims of this study are to learn if NCTD has a protective action against severe proteinuria and consequent interstitial inflammation and fibrosis, and if the inhibition of nuclear factor-kappaB (NF-kappaB) and connective tissue growth factor (CTGF) by NCTD might be involved. Male Sprague-Dawley rats with protein overload nephropathy induced by intraperitoneally injected bovine serum albumin were used as a model. The histopathological examination of kidney tissue in the 9th week by light microscopy and scanning electron microscopy revealed that inflammatory cells had extensively infiltrated into the tubulointerstitial areas with interstitial fibrosis. The administration of NCTD at 0.1 mg/kg/day to the bovine-serum-albumin-injected animal models effectively reduced the proteinuria, and prevented the proteinuria-induced interstitial inflammation and fibrosis. Expressions of the NF-kappaB p65 subunit and CTGF, detected by immunohistochemistry, Western blotting and reverse-transcription polymerase chain reaction, were upregulated in protein overload nephropathy and were attenuated by NCTD. Inhibition of the expressions of the NF-kappaB p65 subunit and CTGF was one beneficial effect of NCTD. These results suggest that in addition to the antiproteinuric action of NCTD, due to its anti-inflammatory and antifibrotic effects as shown in the present study, it may become a therapeutic agent for proteinuria and its associated chronic inflammatory and fibrotic nephropathy.

Benefit of an operating vehicle preventing peritonitis in peritoneal dialysis patients: a retrospective, case-controlled study.

BACKGROUND: Peritonitis, which is one of the leading complications of peritoneal dialysis (PD) worldwide, severely affected morbidity and mortality of the PD patients. Although many efforts have been made to prevent PD-related peritonitis, it seems impossible to prevent it completely. Many causes have been reported to lead to peritonitis, and contamination during bag exchange is one of the important risk factors for peritonitis. METHODS: Here, we introduce an operating vehicle, which we invented to provide a sterile and safe space for bag exchange. A single-center, retrospective, case-control study was undertaken to determine whether this operating vehicle has a protective role in preventing peritonitis. In total, 462 continuous ambulatory peritoneal dialysis patients were included in this study from October 2014 to March 2017. According to their personal will, these patients chose to use operating vehicle or traditional method during their bag exchange. The demographic, clinical and laboratory data of these patients in the two groups were collected, analyzed and compared. RESULTS: Of 462 patients with home dialysis, operating vehicle group consisted of 61 patients, and control group consisted of 401 patients. In the control group, over 677 patient-years, peritonitis occurred in 69 of 401 patients (17.2%), while in the operating vehicle group, over 60 patient-years, only 4 of 61 patients (6.6%) had episodes of peritonitis. The number of patients suffered from peritonitis was significantly decreased in the operating vehicle group (P = 0.034). Besides, there were a total of 99 episodes of peritonitis, and the rate was 1 episode every 7.2 patient-years in control group and 1 episode every 12 patient-years in the operating vehicle group. There was significant difference between the two groups (0.013). Positive dialysate cultures were obtained in majority of the peritonitis episodes (60.6%). CONCLUSION: Operating vehicle might help to reduce PD-related peritonitis by preventing contamination during bag exchange. Further studies are still needed to demonstrate the protective role of the operating vehicle in preventing peritonitis.

Arkadia-Smad7-mediated positive regulation of TGF-beta signaling in a rat model of tubulointerstitial fibrosis.

BACKGROUND/AIMS: Upregulation of transforming growth factor beta (TGF-beta)/Smad signaling has been implicated in the primary pathogenesis of renal fibrosis. The ubiquitin-proteasome pathway has an important influence on TGF-beta signaling through regulating Smad degradation. As E3 ubiquitin ligases, both Arkadia and Smurf2 are involved in this prosess. In this study, we focused on Arkadia, Smurf2, Smad7, and TGF-beta type I receptor (TbetaRI), principal molecules in the regulation of TGF-beta signaling, to understand the regulatory mechanism of ubiquitin-proteasomal degradation of TGF-beta signaling in the pathogenesis of renal fibrosis. METHODS: A unilateral ureteral obstruction (UUO) model was employed, and sham-operated rats were used as controls. Renal lesions and the expression of Arkadia, Smurf2, Smad7, TbetaRI, TGF-beta1, and type 1 collagen (COL-1) were detected by Western blot, immunoprecipitation, immunohistochemistry, and/or reverse transcription-polymerase chain reaction. RESULTS: The results indicated progressive tubulointerstitial fibrosis, high expression levels of Arkadia, Smurf2, TbetaRI, TGF-beta1 mRNA, type 1 collagen mRNA, and Smad7 mRNA, and low levels of Smad7 protein in the kidneys of rats with unilateral ureteral obstruction, in which Smurf2 interacted with both Smad7 and TbetaRI, and Arkadia only interacted with Samd7 but not with TbetaRI. CONCLUSION: Reduction of Smad7 resulting from ubiquitin-dependent degradation may be mainly attributed to Arkadia, and Arkadia-Smad7-mediated positive regulation of TGF-beta signaling may play a promoting role in the progression of tubulointerstitial fibrosis.

Inhibition effect of small interfering RNA of connective tissue growth factor on the expression of vascular endothelial growth factor and connective tissue growth factor in cultured human peritoneal mesothelial cells.

BACKGROUND: The peritoneum response to peritoneal dialysis can lead to fibrosis. The transforming growth factor beta1 (TGF-beta1) plays a key role in regulating tissue repair and remodelling after injury. Connective tissue growth factor (CTGF), a downstream mediator of TGF-beta1 inducing fibrosis, has been implicated in peritoneal fibrosis. Vascular endothelial growth factor (VEGF) plays a key role in angiogenesis that can hasten peritoneal fibrosis. In this study, we investigated the effect of small interfering RNA (siRNA) of CTGF by pRETRO-SUPER (PRS) retrovirus vector on the expression of CTGF and VEGF in human peritoneal mesothelial cells. METHODS: Retrovirus producing CTGF siRNA were constructed from the inverted oligonucleotides and transferred into packaging cell line PT67 with lipofectamine, and the virus supernatant was used to infect human peritoneal mesothelial cell (HPMC). The cells were divided into seven groups: low glucose DMEM, low glucose DMEM + TGF-beta1 5 ng/ml, low glucose DMEM + TGF-beta1 5 ng/ml + PRS-CTGF-siRNA(1-4) and low glucose DMEM + TGF-beta1 5 ng/ml + PRS. The expression of CTGF and VEGF were measured by semiquantitative RT-PCR and Western blot. RESULTS: Low levels of CTGF and VEGF were detected in confluent HPMCs. Following stimulation with TGF-beta1, the levels of CTGF and VEGF were significantly upregulated (P < 0.01). Introduction of PRS-CTGF-siRNA(1-4) resulted in the significant reduction of CTGF mRNA and protein, and VEGF mRNA (P < 0.01), especially in groups PRS-CTGF-siRNA1 and PRS-CTGF-siRNA4. The introduction of PRS void vector did not have these effects (P > 0.05). CONCLUSIONS: The expression of CTGF siRNA mediated by PRS retrovirus vector can effectively reduce the level of CTGF and VEGF induced by TGF-beta1 in cultured HPMCs. This study may provide potential therapeutic strategies to prevent the peritoneal fibrosis.