Deformation and motion of a charged conducting drop in a dielectric liquid under a nonuniform electric field

As a tool for transporting a drop inside another fluid, a charged conducting drop driven by Coulombic force is considered. Specifically, deformation and motion of a charged conducting drop under nonuniform electric fields are studied using the perturbation method. For simplicity in analysis, the applied electric field is assumed to be expressed as the sum of a uniform field and a linear field and the flow is assumed to be in the Stokes flow range. The deformed drop shape due to electrical stress is computed to the first order of the electrical Weber number (W). Then the electric force and the hydrodynamic drag are computed to derive the formula of the translation velocity, which is valid up to O(W). Several important results have also been obtained for the effect of drop deformation on the electric and hydrodynamic forces exerted on the drop.

Vascular endothelial growth factor gene polymorphisms associated with prognosis for patients with gastric cancer

BACKGROUND

The present study analyzed vascular endothelial growth factor (VEGF) gene polymorphisms and their impact on the prognosis for patients with gastric cancer.

PATIENTS AND METHODS

Five hundred and three consecutive patients with surgically resected gastric adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from paraffin-embedded tissue and four VEGF (-460T > C, -116G > A, +405G > C, and +936C > T) gene polymorphisms were determined using a polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

The survival analysis showed no association of three VEGF gene polymorphisms with the prognosis. For the +936C > T polymorphism, the T/T genotype, however, had a worse overall survival (OS) compared with the C/C genotype (P = 0.037). The -460 T/C or C/C genotype was a poor prognostic factor in patients with stage 0 or I gastric cancer (OS: hazard ratio (HR) = 3.96, disease-free survival (DFS): HR = 4.87). In the haplotype analysis, the CACC haplotype was associated with a significantly worse survival when compared with the TGGC haplotype (OS: HR = 1.72, DFS: HR = 1.73).

CONCLUSIONS

VEGF gene polymorphisms were found to be an independent prognostic marker for patients with gastric cancer. Consequently, the analysis of VEGF gene polymorphisms can help identify patient subgroups at high risk of a poor disease outcome.

Placental expression of the membrane form of folate binding protein during pregnancy in swine

Previous experiments indicated that secreted (s) and membrane (m) forms of folate binding protein (FBP) are present in the intrauterine environment of the pig. Our previous studies indicated that the two forms were produced sequentially; the secreted form was present in the intrauterine glands until Day 20 of gestation, whereas binding analysis indicated that folate binding increased dramatically in placental membranes until Day 50 of gestation. However, the cell types expressing mFBP have not been investigated. In this experiment, uterine wall sections from Day 20, 35, 50, 70, 90, and 105 of gestation were collected at slaughter and fixed, and subjected to in situ hybridization analysis for mFBP expression. The mFBP mRNA was expressed by both columnar and cuboidal epithelia of the placental folds and expression appeared to be similar throughout gestation. Therefore, the placenta expressed mFBP from Day 35 of gestation onward, consistent with the concept that sFBP and mFBP occur sequentially during gestation in swine, and that placental mFBP expression plays a role in folate transport after a functional chorioallantoic placenta is established (between Day 20 and 35).

Effects of PGC-1alpha on TNF-alpha-induced MCP-1 and VCAM-1 expression and NF-kappaB activation in human aortic smooth muscle and endothelial cells

Increased oxidative stress in vascular cells is implicated in the pathogenesis of atherosclerosis. Reactive oxygen species (ROS) induce vascular inflammation via the proinflammatory cytokine/NF-kappaB pathway. Several lines of evidence suggest that peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1alpha) is an important regulator of intracellular ROS levels. However, no studies have examined the effects of PGC-1alpha on this process. We investigated the effects of PGC-1alpha on inflammatory molecule expression and activity of the redox-sensitive transcription factor, NF-kappaB, in vascular cells. PGC-1alpha expressed in human aortic smooth (HASMCs) and endothelial cells (HAECs) is upregulated by AMP-activated protein kinase activators, including metformin, rosiglitazone and alpha-lipoic acid. Tumor necrosis factor-alpha (TNF-alpha), a major proinflammatory factor in the development of vascular inflammation, stimulates intracellular ROS production through an increase in both mitochondrial ROS and NAD(P)H oxidase activity. Adenovirus-mediated overexpression of the PGC-1alpha gene in HASMCs and HAECs leads to a significant reduction in intracellular and mitochondrial ROS production as well as NAD(P)H oxidase activity. Consequently, NF-kappaB activity and MCP-1 and VCAM-1 induced by TNF-alpha are suppressed. Our data support the possibility that agents stimulating PGC-1alpha expression in the vasculature aid in preventing the development of atherosclerosis.

α-Lipoic acid inhibits matrix metalloproteinase-9 expression by inhibiting NF-κB transcriptional activity

The migration of vascular smooth muscle cells (VSMCs) into the intima, an important step in injury-induced neointimal hyperplasia, requires the activation of nuclear factor-kappaB (NF-kappaB) and the consequent up-regulation of matrix metalloproteinase-9 (MMP-9). This study was undertaken to test for a possible effect of alpha-lipoic acid (ALA), a potent inhibitor of NF-kappaB, on MMP-9 expression. ALA inhibited high-glucose- and TNF-alpha-stimulated VSMC migrations in vitro. It also inhibited high-glucose- and TNF-alpha-induced increases in MMP-9 expression. The activity of MMP-9-promoter constructs with mutations in the NF-kappaB binding site was not inhibited by ALA, indicating an involvement of the NF-kappaB signaling pathway in the ALA-specific inhibition of MMP-9. These data suggest the possibility that ALA may be useful for the prevention of neointimal hyperplasia after angioplasty, by inhibiting the NF-kappaB/MMP-9 pathway, especially with hyperglycemia.

Glucotoxicity in the INS-1 rat insulinoma cell line is mediated by the orphan nuclear receptor small heterodimer partner

Prolonged elevations of glucose concentration have deleterious effects on beta-cell function. One of the hallmarks of such glucotoxicity is a reduction in insulin gene expression, resulting from decreased insulin promoter activity. Small heterodimer partner (SHP; NR0B2) is an atypical orphan nuclear receptor that inhibits nuclear receptor signaling in diverse metabolic pathways. In this study, we found that sustained culture of INS-1 cells at high glucose concentrations leads to an increase in SHP mRNA expression, followed by a decrease in insulin gene expression. Inhibition of endogenous SHP gene expression by small interfering RNA partially restored high-glucose-induced suppression of the insulin gene. Adenovirus-mediated overexpression of SHP in INS-1 cells impaired glucose-stimulated insulin secretion as well as insulin gene expression. SHP downregulates insulin gene expression via two mechanisms: by downregulating PDX-1 and MafA gene expression and by inhibiting p300-mediated pancreatic duodenal homeobox factor 1-and BETA2-dependent transcriptional activity from the insulin promoter. Finally, the pancreatic islets of diabetic OLETF rats express SHP mRNA at higher levels than the islets from LETO rats. These results collectively suggest that SHP plays an important role in the development of beta-cell dysfunction induced by glucotoxicity.

Alpha-lipoic acid inhibits fractalkine expression and prevents neointimal hyperplasia after balloon injury in rat carotid artery

Vascular inflammation induced by the proinflammatory cytokine/NF-kappaB pathway is one of the key mechanisms in the development of neointimal hyperplasia. Accumulating evidence suggests that a recently identified chemokine, fractalkine, is involved in arterial inflammation and atherogenesis. However, no study has examined the expression of neointimal fractalkine and the effects of pharmacological agents on this process. The purposes of this study were to measure neointimal fractalkine expression in the rat carotid artery following balloon injury and to determine if alpha-lipoic acid (ALA) inhibits fractalkine expression and neointimal hyperplasia. Balloon injury of the rat carotid artery induced fractalkine expression in the medial as well as neointimal regions. ALA inhibited this expression and consequently prevented neoinitmal hyperplasia in a balloon-injured rat carotid artery. Additionally, ALA inhibited TNF-alpha-stimulated fractalkine expression in cultured vascular smooth muscle cells (VSMCs), a process which is mediated through the NF-kappaB pathway. In addition to fractalkine, ALA successfully inhibited TNF-alpha-stimulated expression of vascular cell adhesion molecule-1 and monocyte chemotactic protein-1 in cultured VSMCs. These data suggest that the cytokine-fractalkine system is involved in the pathogenesis of restenosis. The present study supports the possibility that ALA, which inhibits the NF-kappaB/fractalkine pathway, may be used to prevent neointimal hyperplasia after angioplasty or stenting.

Phase II study of capecitabine and irinotecan combination chemotherapy in patients with advanced gastric cancer

The present study was conducted to evaluate the efficacy and safety of a combination regimen of capecitabine plus irinotecan in patients with advanced gastric cancer. Patients with previously untreated metastatic or recurrent, measurable gastric cancer received oral capecitabine 1000 mg m⁻² twice daily from day 1 to 14 and intravenous irinotecan 100 mg m⁻² on days 1 and 8, based on a 3-week cycle. Forty-one patients were enrolled in the current study, among whom 38 were assessable for efficacy and 40 assessable for toxicity. Three complete responses and 16 partial responses were confirmed, giving an overall response rate of 46.3%. At a median follow-up of 269 days, the median time to progression and overall survival were 5.1 and 8.6 months, respectively. Grade 3/4 neutropenia occurred in four patients and grade 3 febrile neutropenia was observed in two patients. Grade 3 diarrhoea and grade 2 hand–foot syndrome occurred in six patients and eight patients, respectively. The combination of capecitabine and irinotecan was found to be well tolerated and effective in patients with advanced gastric cancer. Accordingly, this regimen can be regarded as one of first-line treatment options for advanced gastric cancer.

Risk-factor analysis for predicting progressive- or quiescent-type chronic graft-versus-host disease in a patient cohort with a history of acute graft-versus-host disease after allogeneic stem cell transplantation

This study attempts to identify variables that can predict the development of progressive- or quiescent-type chronic GVHD (pq cGVHD) and transplant outcomes after the diagnosis of cGVHD in 99 patients who experienced acute GVHD (aGVHD) after allogeneic SCT. The prognostic significance of various clinical parameters at diagnosis of cGVHD was examined to determine the prognostic factors for GVHD-specific survival (GSS) in patients with pq cGVHD. Among 118 patients who experienced any degree of aGVHD, 99 were evaluated for cGVHD. The incidence of overall and extensive pq cGVHD at 2 years was estimated as 84.4 and 63.1%, respectively. A multivariate analysis showed that severe aGVHD (grade 3, 4) (P=0.022), primary treatment failure (P=0.009) and elevated alkaline phosphatase (P=0.001) were all significant independent factors predicting a higher overall incidence of pq cGVHD. The GSS and probability of systemic immunosuppressive treatment at 2 years after diagnosis of cGVHD were estimated as 55.9 and 51.9%. GVHD-specific survival was significantly associated with performance status (P=0.004) and lymphocytopenia (<or=1000/microl, P=0.022) at diagnosis of cGVHD by Cox's proportional hazard model. Severe aGVHD, primary treatment failure (PTF), lymphocytopenia and elevated alkaline phosphatase may be useful predictive factors for the development of pq cGVHD in patients who experience aGVHD after allogeneic SCT.

Size removal on polyester fabrics by plasma source ion implantation device

Plasma treatment was evaluated as an alternative clean desizing technology in this work. As indicated by weight loss, O2 plasma treatment efficiently removed sizing agents such as polyvintyl alcohol (PVA), polyacrylic acid esters and their mixture (MIX) on polyethylene terephthalate (PET) fabrics. SEM pictures of the plasma treated samples directly proved the disappearance of the sizing agents. XPS analysis showed apparent changes in chemical composition and functional groups of the PET surface after O2 plasma treatment. Carbon content decreased due to the removal of sizing agents while oxygen content increased. O2 plasma treatment also increased hydrophilic functional groups of sizing agents, which is confirmed by C1s and O1s deconvolution analyses. After O2 plasma treatment, the PET fabric was subjected to conventional desizing process at different temperatures. Except for the PET fabric sized with PVA, plasma-treated fabrics showed more efficient desizing results when compared with untreated fabrics. Furthermore, the desizing effluent from the treated fabric gave lower TOC, COD and BOD values.

Protective role of interleukin-10 promoter gene polymorphism in the pathogenesis of invasive pulmonary aspergillosis after allogeneic stem cell transplantation

The current study attempted to evaluate the association between the IL-10 promoter gene single nucleotide polymorphism (SNP) and invasive pulmonary aspergillosis (IPA) after allogeneic stem cell transplantation (SCT) in 105 patients. Three single-nucleotide polymorphisms were investigated in the proximal region of the IL-10 promoter gene (-1082/-819/-592). Two haplotypes (1082*A/819*T/592*A [ATA] and 1082*A/819*C/592*C [ACC]) were found in the current study. The overall incidence of IPA was estimated as 14.1+/-4.5% with a median onset at 186 days post-transplant (62 approximately 405 days). An increased occurrence of IPA was noted dependent on the IL-10 haplotype (0% vs 11.5+/-6.4% vs 19.7+/-7.7% for ACC/ACC vs ATA/ACC vs ATA/ATA haplotype, P=0.0307 when comparing ACC with non-ACC haplotype). In a multivariate survival analysis using Cox's proportional hazard model, the IL-10 promoter gene SNPs were identified as an independent predictive factor for the development of IPA (P=0.012, hazard ratio (HR) 9.3), along with an histocompatibility leukocyte antigen (HLA)-identical donor (P=0.005, HR 16.3), the CD34+ cell dose transplanted (P=0.004, HR 26.5), and time-dependent chronic graft-versus-host disease (GVHD; P=0.049, HR 16.0). The IL-10 ACC haplotype was found to have an apparent protective role in the development of IPA after allogeneic transplantation, regardless of HLA-disparity or chronic GVHD.

Atrophic gastritis in young children and adolescents

BACKGROUND

Helicobacter pylori associated gastric cancer arises via a multistage process, with atrophic gastritis being the precursor lesion. Helicobacter pylori is typically acquired in childhood, yet little is known of the prevalence of atrophic gastritis in childhood.

AIM

To study atrophic gastritis among children from countries with high gastric cancer incidence.

METHODS

Sections from topographically mapped gastric biopsy specimens from children undergoing clinically indicated endoscopy in Korea and Colombia were evaluated using visual analogue scales. Atrophy was defined as loss of normal glandular components, including replacement with fibrosis, intestinal metaplasia (IM), and/or pseudopyloric metaplasia of the corpus (identified by the presence of pepsinogen I in mucosa that was topographically corpus but phenotypically antrum).

RESULTS

One hundred and seventy three children, 58 from Korea (median age, 14 years) and 115 from Colombia (median age, 13 years), were studied. Helicobacter pylori was present in 85% of Colombian children versus 17% of Korean children (p<0.01). Atrophic mucosa near the antrum-corpus border was present in 16% of children, primarily as pseudopyloric metaplasia (31%, IM; 63%, pseudopyloric metaplasia; 6%, both). The median age of children with corpus atrophy was 15 (range, 7-17) years.

CONCLUSION

Gastric atrophy occurs in H pylori infected children living in countries with high gastric cancer incidence. Identification and characterisation of the natural history of H pylori gastritis requires targeted biopsies to include the lesser and greater curve of the corpus, starting just proximal to the anatomical antrum-corpus junction, in addition to biopsies targeting the antrum and cardia.

The use of microarrays to define functionally-related genes that are differentially expressed in the cycling pig uterus

In swine and other livestock, the uterine endometrium exhibits dramatic morphological and secretory changes throughout the oestrous cycle and during pregnancy. Such physiological changes are a reflection of extremely complex interactions between gene products (RNA and protein). The recent development of genomics and proteomics methods, as well as associated bioinformatics tools, has provided the means to begin characterising such interactions. Indeed, the analysis of the transcriptome and proteome of cells and tissues now comprises a new field of study known as 'systems biology'. Currently, the most powerful technique available to the systems biologist is the microarray. These platforms represent oligonucleotide or cDNA fragments spotted in a specified high-density pattern on a solid support. Hybridisation of fluorescently-tagged cDNAs from different tissue sources permits the measurement of thousands of RNAs in parallel. The method permits the identification of genes that are present at different amounts between the two tissues and, more importantly, it permits the identification of groups of genes (clusters) that are expressed in comparable patterns. Results from a recent expression profiling experiment are described. The goal of the profiling experiment was to define genes that are differentially expressed in endometrium during the oestrous cycle. The experiment used an in-house cDNA microarray with > 14,000 distinct cDNAs cloned from reproductive tissues. Total RNAs from cyclic endometrium (Days 0, 3, 6, 10, 12, 14 and 18 post-oestrus) were reverse transcribed into cDNAs, labelled with fluorescent dye and hybridised to the arrays along with cDNAs derived from a reference RNA pool. A total of 4,827 genes were found to differ significantly at some time during the oestrous cycle. Clustering methods were able to define numerous groups of similarly expressed genes. These data will help to define the complex patterns of endometrial genes acting in concert to create the environments required for fertilisation, embryo growth and conceptus development in swine.

Parathion degradation and toxicity reduction in solar photocatalysis and photolysis

The solar photocatalytic degradation of methyl parathion was investigated using a circulating TiO2/solar light reactor. Under solar photocatalysis condition, parathion was more effectively degraded than solar photolysis and TiO2-only conditions. With solar photocatalysis, 20 mg/L of parathion was completely degraded within 60 min with a TOC decrease of 63% after 150 min. The main ionic byproducts during photocatalysis recovered from parathion degradation were mainly as NO3-, NO2- and NH4+, 80% of the sulphur as SO4(2-), and 5% of phosphorus as PO4(3-). The organic intermediates 4-nitrophenol and methyl paraoxon were also identified, and these were further degraded in solar photocatalytic condition. Two different bioassays (Vibrio fischeri and Daphnia magna) were used to test the acute toxicity of solutions treated by solar photocatalysis and photolysis. The Microtox test using V. fischeri showed that the toxicity expressed as EC50 (%) value increased from 5.5% to >82% in solar photocatalysis, indicating that the treated solution is non-toxic, but only increased from 4.9 to 20.5% after 150 min in solar photolysis. The acute toxicity test using D. magna showed that EC50 (%) increased from 0.05 to 1.08% under solar photocatalysis, but only increased to 0.12% after 150 min with solar photolysis, indicating the solution is still toxic. The pattern of toxicity reduction parallels the decrease in TOC and the parathion concentrations.

Phase II study of concurrent chemoradiotherapy with capecitabine and cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck

We aimed to evaluate the efficacy and safety of concurrent chemoradiotherapy with capecitabine and cisplatin in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN). In total, 37 patients with stage III or IV SCCHN were enrolled on the study. The chemotherapy consisted of two cycles of intravenous cisplatin of 80 mg m⁻² on day 1 and oral capecitabine 825 mg m⁻² twice daily from day 1 to day 14 at 3-week intervals. The radiotherapy (1.8–2.0 Gy 1 fraction day⁻¹ to a total dose of 70–70.2 Gy) was delivered to the primary tumour site and neck. The primary tumour sites were as follows: oral cavity (n=6), oropharynx (n=11), hypopharynx (n=8), larynx (n=3), nasopharynx (n=6), and paranasal sinus (n=3). After the chemoradiotherapy, 29 complete responses (78.4%) and 6 partial responses (16.2%) were confirmed. Grade 3 or 4 neutropenia occurred only in two patients, plus grade 3 febrile neutropenia was observed only in one patient. At a median follow-up duration of 19.8 months, the estimated overall survival and progression-free survival rate at 2-year was 76.8 and 57.9%, respectively. Concurrent chemoradiotherapy with capecitabine and cisplatin was found to be well tolerated and effective in patients with locally advanced SCCHN.

Effectiveness of Transdermal Fentanyl Patch for Treatment of Acute Pain Due to Oral Mucositis in Patients Receiving Stem Cell Transplantation

The current study was performed to evaluate the effectiveness and safety of transdermal therapeutic system (TTS) fentanyl in the management of acute pain due to oral mucositis in patients receiving stem cell transplantation. A cohort of consecutive patients with painful oral mucositis were enrolled. Initially, 25 microg/h of TTS fentanyl was administered for the treatment of oral mucositis pain. The pain score, based on a visual analogue scale, and mood and quality of sleep as determined by EORTC QLQ-C30 (European Organization for Research and Treatment of Cancer, Quality of Life Questionnaire, Cancer 30), were all recorded before the treatment, then 2, 6, and 10 days later. Twenty-two patients with hematologic malignancies were enrolled. Three patients were excluded from the response assessment, as their TTS fentanyl treatment was stopped owing to related complaints, including severe dizziness, severe vomiting, and an extensive body rash. The total duration of the treatment was 8 days (range, 6-15 days) and the total amount of TTS fentanyl administered per patient was 2.21 at 25 microg/h and 0.63 at 50 microg/h. Six (31.6%) of the remaining 19 patients required an escalated dose of TTS fentanyl at 50 mug/h. The mean pain scores before treatment and 2, 6, and 10 days later were 6.68, 5.17, 3.42, and 2.13, respectively (P < .001). Eight (42.1%) and seven (36.8%) patients experienced improved sleep and mood after treatment, respectively. The TTS fentanyl was effective in both relieving oral mucositis pain with an excellent tolerability and improving the quality of life for hematological patients receiving high-dose chemotherapy with stem cell transplantation.

Prognostic significance of platelet recovery pattern after allogeneic HLA-identical sibling transplantation and its association with severe acute GVHD

Thrombocytopenia (TP) is a frequent complication after allogeneic stem cell transplantation (SCT) and regarded as a poor prognostic factor when assessed beyond day 100. However, little is known about the clinical significance of the platelet recovery pattern before chronic graft-versus-host disease (GVHD) develops. Eighty-five patients undergoing HLA-identical sibling SCT were stratified according to their platelet recovery pattern between day +30 and +90 and the transplant outcomes analyzed, along with the association of each component of the acute GVHD grading system. Fifteen patients (18%) were classified with persistent TP, 33 patients (39%) with unstable TP, and 37 patients (43%) as non-TP. Persistent TP, which was strongly associated with severe acute GVHD (P<0.001), exhibited the worst 2-year OS (P<0.0001) and highest NRM (P<0.0001) and opportunistic infection rates (P<0.0001). In multivariate analyses, the platelet recovery pattern was identified as an independent prognostic factor (P=0.02) together with the disease risk (P=0.02) in terms of OS, and the only independent prognostic factor in terms of NRM (P=0.005) and the incidence of infectious events (P<0.001). Persistent TP was strongly associated with the development of extensive chronic GVHD (P=0.03). The platelet recovery pattern between day +30 and +90 can be used to predict the prognosis of SCT recipients.

Impact of ABO incompatibility on outcome after allogeneic peripheral blood stem cell transplantation

Few studies have addressed the incidence of graft-versus-host disease (GVHD) or survival after ABO-incompatible allogeneic peripheral blood stem cell transplantation (PBSCT). We analyzed the clinical outcome of ABO incompatibility after allogeneic PBSCT. A total of 89 consecutive adult patients with hematological diseases including 49 ABO-identical, 20 major, 15 minor, and five bidirectional ABO-incompatible transplants were enrolled from four medical centers in Korea. No significant difference in engraftment times, graft failure, or transfusion requirements between groups was noted. A clinical diagnosis of severe immune hemolysis or pure red cell aplasia was not made for any patient after transplantation. The incidence of acute or chronic GVHD did not statistically differ between groups. With a median follow-up duration of 13 months (range, 0.5-61 months), the 3-year overall survival estimates for the ABO-identical, major/bidirectional, and minor group were 44.6.0+/-9.0, 43.1+/-11.6, and 43.8+/-13.5%, respectively (P=0.8652), while the 3-year disease-free survival estimates were 33.8+/-7.6, 39.9+/-11.4, and 45.7+/-13.1%, respectively (P=0.8546). We observed that time to neutrophil, platelet, and red blood cell engraftment, transfusion requirements, incidence of acute or chronic GVHD, relapse, and survival were not influenced by ABO incompatibility after allogeneic PBSCT from HLA-matched sibling donors.

Degradation of parathion and the reduction of acute toxicity in TiO2 photocatalysis

Photocatalytic degradation of methyl parathion was done using a circulating TiO2/UV and TiO2/solar reactor. Indoor experimental results showed that, under the photocatalysis conditions, parathion was more effectively degraded than under the photolysis and TiO2 only conditions. Parathion (38 microM) was completely degraded under photocatalysis within 90 min, and more than 80% TOC decrease after 150 minutes. The main ionic byproducts during the photocatalysis were measured, and almost complete nitrogen recovery was achieved as mainly NO3- NO2-, and NH4+, and 80% of sulfur as recovered as SO4(2)-. Organic intermediates such as nitrophenol and methyl paraoxon were also identified during the photocatalysis of parathion, and these were further degraded after 90 minutes. Microtox bioassay using Vibrio fischeri was used in evaluating the toxicity of solutions treated by photocatalysis and photolysis of parathion. The results showed that the acute toxicity expressed as EC50 almost reduced after 90 min under the photocatalysis condition whereas only 40% reduction of toxicity as EC50 was achieved in photolysis condition. The outdoor results using a TiO2/solar system were similar to the TiO2 indoor system, indicating the possibility of applying TiO2/solar system for the treatment of parathion-contaminated water.

Chronic exposure to GLP-1R agonists promotes homologous GLP-1 receptor desensitization in vitro but does not attenuate GLP-1R-dependent glucose homeostasis in vivo

Glucagon-like peptide-1 (GLP-1) stimulates glucose-dependent insulin secretion and inhibits food intake, gastric emptying, and glucagon secretion, actions that promote reduction of fasting and postprandial glycemia in subjects with type 2 diabetes. The rapid degradation of native GLP-1 has engendered interest in more stable longer-acting GLP-1 receptor agonists such as exendin-4 (Ex-4); however, the potential consequences of sustained GLP-1 receptor activation leading to receptor desensitization has not been extensively studied. We have now examined a range of GLP-1 receptor-dependent responses following treatment with Ex-4 using INS-1 cells in vitro and both wild-type control and MT-Ex-4 transgenic mice in vivo. Although both GLP-1 and Ex-4 acutely desensitized GLP-1 receptor-dependent cAMP accumulation in INS-1 cells, Ex-4 produced more sustained receptor desensitization, relative to GLP-1, in both acute (5-120 min) and chronic (24-72 h) experiments. PMA (4-phorbol 12-myristate 13-acetate) but not glucagon, glucose-dependent insulinotropic polypeptide (GIP), or epinephrine produced heterologous desensitization in vitro. MT-Ex-4 transgenic mice exhibited a reduced glycemic response to oral but not intraperitoneal glucose challenge following acute Ex-4 administration. In contrast, no differences in glycemic excursion or plasma insulin were observed after 1 week of twice-daily Ex-4 administration to wild-type versus MT-Ex-4 mice. Similarly, the levels of insulin, pdx-1, and GLP-1 receptor mRNA transcripts were comparable in wild-type and MT-Ex-4 transgenic mice after 1 week of Ex-4 administration. However, repeated Ex-4 administration significantly reduced food intake in MT-Ex-4 but not in wild-type mice. These findings illustrate that although Ex-4 is more potent than native GLP-1 in producing GLP-1 receptor desensitization in vitro, chronic exposure to Ex-4 in normal or transgenic mice is not associated with significant downregulation of GLP-1 receptor-dependent responses coupled to glucose homeostasis in vivo.