Multileaf Collimator Modeling and Commissioning for Complex Radiation Treatment Plans Using 2-Dimensional (2D) Diode Array MapCHECK2.

Purpose: This study aims to develop a data-collecting package ExpressMLC and investigate the applicability of MapCHECK2 for multileaf collimator (MLC) modeling and commissioning for complex radiation treatment plans. Materials and methods: The MLC model incorporates realistic parameters to account for sophisticated MLC features. A set of 8 single-beam plans, denoted by ExpressMLC, is created for the determination of parameters. For the commissioning of the MLC model, 4 intensity modulated radiation therapy (IMRT) plans specified by the AAPM TG 119 report were transferred to a computed tomography study of MapCHECK2, recalculated, and compared to measurements on a Varian accelerator. Both per-beam and composite-beam dose verification were conducted. Results: Through sufficient characterization of the MLC model, under 3%/2 mm and 2%/2 mm criteria, MapCHECK2 can be used to accurately verify per beam dose with gamma passing rate better than 90.9% and 89.3%, respectively, while the Gafchromic EBT3 films can achieve gamma passing rate better than 89.3% and 85.7%, respectively. Under the same criteria, MapCHECK2 can achieve composite beam dose verification with a gamma passing rate better than 95.9% and 90.3%, while the Gafchromic EBT3 films can achieve a gamma passing rate better than 96.1% and 91.8%; the p-value from the Mann Whitney test between gamma passing rates of the per beam dose verification using full MapCHECK2 package calibrated MLC model and film calibrated MLC model is .44 and .47, respectively; the p-value between those of the true composite beam dose verification is .62 and .36, respectively. Conclusion: It is confirmed that the 2-dimensional (2D) diode array MapCHECK2 can be used for data collection for MLC modeling with the combination of the ExpressMLC package of plans, whose doses are sufficient for the determination of MLC parameters. It could be a fitting alternative to films to boost the efficiency of MLC modeling and commissioning without sacrificing accuracy.

A cloud-based consultation and collaboration system for radiotherapy: Remote decision support services for community radiotherapy centers.

PURPOSE: This study aimed to establish a cloud-based radiotherapy consultation and collaboration system, then investigated the practicability of remote decision support for community radiotherapy centers using the system. METHODS AND MATERIALS: A cloud-based consultation and collaboration system for radiotherapy, OncoEvidance®, was developed to provide remote services of LINAC modeling, simulation CT data import/export, target volume and organ-at-risk delineation, prescription, and treatment planning. The system was deployed on a hybrid cloud. A federate of public nodes, each corresponding to a medical institution, are managed by a central node where a group of consultants have registered. Users can access the system through network using computing devices. The system has been tested at three community radiotherapy centers. One accelerator was modeled. 12 consultants participated the remote radiotherapy decision support and 77 radiation treatment plans had been evaluated remotely. RESULTS: All the passing rates of per-beam dose verification are > 94% and all the passing rates of composite beam dose verification are > 99%. The average downloading time for one set of simulation CT data for one patient from Internet was within 1 min under the cloud download bandwidth of 8 Mbps and local network bandwidth of 100 Mbps. The average response time for one consultant to contour target volumes and make prescription was about 24 h. And that for one consultant to design and optimize a IMRT treatment plan was about 36 h. 100% of the remote plans passed the dosimetric criteria and could be imported into the local TPS for further verification. CONCLUSION: The cloud-based consultation and collaboration system saved the travel time for consultants and provided high quality radiotherapy to patients in community centers. The under-staffed community radiotherapy centers could benefit from the remote system with lower cost and better treatment quality control.

Role of the hydrogen sulfide-releasing donor ADT-OH in the regulation of mammal neural precursor cells.

Neural precursor cells (NPCs) generate new neurons to supplement neuronal loss as well as to repair damaged neural circuits. Therefore, NPCs have potential applications in a variety of neurological diseases, such as spinal cord injury, traumatic brain injury, and glaucoma. Specifically, improving NPCs proliferation and manipulating their differentiated cell types can be a beneficial therapy for a variety of these diseases. ADT-OH is a slow-releasing organic H2 S donor that produces a slow and continuous release of H2 S to maintain normal brain functions. In this study, we aimed to explore the effect of ADT-OH on NPCs. Our results demonstrated that ADT-OH promotes self-renewal and antiapoptosis ability of cultured NPCs. Additionally, it facilitates more NPCs to differentiate into neurons and oligodendrocytes, while inhibiting their differentiation into astrocytes. Furthermore, it enhances axonal growth. Moreover, we discovered that the mRNA and protein expression of ß-catenin, TCF7L2, c-Myc, Ngn1, and Ngn2, which are key genes that regulate NPCs self-renewal and differentiation, were increased in the presence of ADT-OH. Altogether, these results indicate that ADT-OH may be a promising drug to regulate the neurogenesis of NPCs, and needs to be studied in the future for clinical application potential.

Comparison and quantification of different concurrent chemotherapy regimens with radiotherapy in locally advanced non-small cell lung cancer: Clinical outcomes and theoretical results from an extended LQ and TCP model.

PURPOSE: To develop a new radiobiological model and compare the efficacy of four concurrent chemotherapy regimens administered with radiotherapy in locally advanced non-small-cell lung cancer (LANSCLC) by in-field locoregional progression-free survival (LPFS). MATERIALS AND METHODS: 151 LANSCLC patients were reviewed and divided into 5 groups according to their concurrent chemotherapy regimens, including 24 patients treated with radiotherapy alone, 30 treated with concurrent 4-week etoposide-cisplatin (EP), 26 with 3-week pemetrexed-cisplatin (AP), 37 with weekly paclitaxel-cisplatin (TP) and 34 with weekly docetaxel-cisplatin (DP). In-field LPFS and toxicities were compared among groups. A novel tumor control probability (TCP) model, LQRGC, incorporating four "R"s of radiobiology, Gompertzian tumor growth and chemotherapeutic effect, was related to in-field LPFS. Chemo-induced biologically effective doses (BEDs) in LQRGC/TCP model were used to quantify the concurrent chemotherapeutic efficacy. RESULTS: The median follow-up time was 54.5 months. The weekly DP and 4-week EP groups had favorable median in-field LPFS (EP:46.2 months, AP:30.3 months, TP:12.2 months, DP: not reached, radiotherapy alone: 12.2 months, p = 0.001). The 4-week EP group had a higher incidence of ≥grade 3 leukopenia (EP:76.7%, AP:15.4%, TP:24.3%, DP:14.7%, radiotherapy alone: 12.5%, p < 0.001) than the other four. The LQRGC/TCP model fitted well with the in-field LPFS with the average absolute and relative fitting errors of 6.36% and 12.12%. The chemo-induced BEDs of EP, AP, TP and DP were 5.17, 0.63, 1.89 and 2.52 Gy, respectively. CONCLUSION: The LQRGC/TCP model achieved promising fitting accuracy for in-field LPFS. As quantified by the model, the 4-week EP and weekly DP showed higher chemo-induced BEDs when concurrently administered with radiotherapy in LANSCLC.

A novel angular dependency model for MatriXX response and its application to true composite dose verification for IMRT plans.

PURPOSE: This paper proposes a model for the angular dependency of MatriXX response and investigates whether MatriXX, with the angular-model-based approach can be applied to true composite dose verification for IMRT plans. METHOD: This model attributes the angular dependence of MatriXX response to dynamical translation of its effective measurement plane (EMP) due to the change of beam angle. Considering this mechanism, true composite dose verifications for IMRT plans specified in AAPM TG 119 report using both MatriXX and Gafchromic EBT3 films were undertook and compared to validate the applicability of MatriXX for patient specific QA of composite beam IMRT plans. Dose verifications using MatriXX with and without angular-model-based approach were performed. RESULTS: MatriXX with angular-model-based approach achieved gamma passing rates with 3%/3 mm and 3%/2 mm criteria better than 98.3% and 98.1% respectively for true composite dose verification of plans in AAPM TG 119 report. The 3%/3 mm and 3%/2 mm gamma passing rates using MatriXX without angular-model-based approach ranged from 85.8% to 98.2% and from 81.3% to 96.5%, respectively. The p-values from the single sided paired t-test indicated no statistical difference between the passing rates from MatriXX with angular-model-based approach and from films, and significant difference between the passing rates from uncorrected MatriXX and from films. CONCLUSION: The proposed model for angular dependent MatriXX response is necessary and effective. Dose verification using MatriXX with angular-model-based approach is acceptable for true composite beam IMRT plans with required accuracy to simplify patient specific QA.

Comprehensive evaluation of microRNA-10b in digestive system cancers reveals prognostic implication and signaling pathways associated with tumor progression.

Background: Digestive system cancers (DSCs) have been recognized to be linked with high morbidity and mortality. Recent studies have reported that microRNA-10b (miR-10b) is abnormally expressed in DSCs and associated with prognosis. However, the inconclusive results and unknown underlying mechanisms promoted us to perform this study. Methods: We systematic searched several databases for eligible studies and conducted quantitative analysis for evidence regarding the associations between miR-10b and survival outcome of DSCs. We also performed a series of bioinformatics analyses to uncover the potential mechanisms. Results: A total of 32 eligible studies with 3392 patients were included. Increased miR-10b expression was linked with unfavorable overall survival (OS) in DSCs (HR=1.72; 95% CI: 1.30-2.27; P <0.001). When stratified by tumor type, the impact of miR-10b overexpression on poor prognosis was observed in colorectal cancer, gastric cancer, hepatocellular carcinoma, and esophageal carcinoma, but not in pancreatic cancer. Subsequently, we predicted the targets of miR-10b and conducted functional enrichment analyses. The results disclosed that miR-10b targets were predominantly enriched in some vital biological terms and pivotal signaling pathways associated with tumor progression including cell cycle, FoxO, proteoglycans, central carbon metabolism, p53, Notch, HIF-1, focal adhesion, AMPK, and pancreatic cancer. Moreover, a protein-protein interaction (PPI) network was also constructed to identify the top ten hub genes and significant modules and demonstrated the underlying interactions among them. Conclusion: Our results indicated that miR-10b could act as a significant biomarker in the prognosis DSCs. However, more research should be performed to test these findings.

Investigating the loco-regional control of simultaneous integrated boost intensity-modulated radiotherapy with different radiation fraction sizes for locally advanced non-small-cell lung cancer: clinical outcomes and the application of an extended LQ/TCP model.

BACKGROUND: To investigate the loco-regional progression-free survival (LPFS) of intensity-modulated radiotherapy (IMRT) with different fraction sizes for locally advanced non-small-cell lung cancer (LANSCLC), and to apply a new radiobiological model for tumor control probability (TCP). METHODS: One hundred and three LANSCLC patients treated with concurrent radiochemotherapy were retrospectively analyzed. Factors potentially predictive of LPFS were assessed in the univariate and multivariate analysis. Patients were divided into group A (2.0 ≤ fraction size<2.2Gy), B (2.2 ≤ fraction size<2.5Gy), and C (2.5 ≤ fraction size≤3.1Gy) according to the tertiles of fraction size. A novel LQRG/TCP model, incorporating four "R"s of radiobiology and Gompertzian tumor growth, was developed to predict LPFS and compared with the classical LQ/TCP model. RESULTS: With a median follow-up of 22.1 months, the median LPFS was 23.8 months. Fraction size was independently prognostic of LPFS. The median LPFS of group A, B and C was 13.8, 35.7 months and not reached, respectively. Using the new LQRG/TCP model, the average absolute and relative fitting errors for LPFS were 6.9 and 19.6% for group A, 5.5 and 8.8% for group B, 6.6 and 9.5% for group C, compared with 9.5 and 29.4% for group A, 16.6 and 36.7% for group B, 24.8 and 39.1% for group C using the conventional LQ/TCP model. CONCLUSIONS: Hypo-fractionated IMRT could be an effective approach for dose intensification in LANSCLC. Compared with conventional LQ model, the LQRG model showed a better performance in predicting follow-up time dependent LPFS.

Effects of different corticosteroid doses and durations on smoke inhalation-induced acute lung injury and pulmonary fibrosis in the rat.

Excessive inflammation induced by cytokine storm and coagulation disorders is considered the primary characteristic of smoke inhalation-induced acute lung injury (SI-ALI). Glucocorticoids such as methylprednisolone (MP) are commonly used to treat patients with inflammatory diseases; however, the management of ALI or acute respiratory distress syndrome (ARDS) remains controversial. We explored the effects of different MP doses and durations in a rat SI-ALI model. SI-ALI model rats had a high mortality rate and severe lung injury with proinflammatory, procoagulant, and pro-fibrotic changes. We found that a medium MP dose (4 mg/kg) markedly improved survival rates compared with low (0.4 mg/kg) and high (40 mg/kg) doses in the acute phase. A medium dose significantly attenuated lung injury, and reduced proinflammatory cytokine production and neutrophil infiltration into alveoli. Both medium and high MP doses improved coagulation and fibrinolysis conditions compared with low-dose MP. We also explored the effect of different durations of MP treatment on attenuating fibrotic changes in late-phase SI-ALI. Pro-fibrotic chemokine levels were gradually increased, followed by an increase in collagen and fibrin deposition after smoke inhalation. Three and 7-day MP treatments significantly attenuated this process, which was reflected by a reduction in pro-fibrotic chemokine levels. There was no significant difference between 3- and 7-day treatments. We report that a medium MP (4 mg/kg) dose significantly reduced inflammation and coagulation disorders, as well as acute-phase mortality. Three-day MP treatment may sufficiently attenuate fibrotic changes in late-phase SI-ALI.

Misdiagnosis of Intrahepatic Biliary Cystadenoma Located in the Caudate Lobe: A Case Report.

BACKGROUND: Intrahepatic Biliary Cystadenoma (IBC) is rare but has a high incidence of misdiagnosis, especially for experienceless surgeons. CASE: We report a case of IBC located in the caudate lobe and described a typical procedure of misdiagnosing this disease. Finally, the patient was successfully cured, but the procedure of misdiagnosis should attract attention. IBC and atypical biopsy for histological examination are the most important causes of misdiagnosis. Recurrent cystic lesions of the liver and repeated increases in CA 19-9 may suggest a "liver cyst", which is a misdiagnosis. CONCLUSION: The experience and lessons of misdiagnosis, in this case, may help other clinicians diagnose the rare disease accurately.

Gastric fistula secondary to drainage tube penetration: A report of a rare case.

Cases of gastric fistula secondary to drainage tube penetration have rarely been reported. The current study presents a case of gastric penetration caused by misplacement of a drainage tube after a splenectomy. The patient was admitted to the Department of Hepatobiliary Surgery, (Shaoxing People's Hospital, Shaoxing Hospital of Zhejiang University, Shaoxing, Zhejiang, China) for blunt abdominal trauma due to injuries sustained in an automobile accident. A ruptured spleen was found and successfully removed surgically. On post-operative day 7, the patient complained of slight discomfort and tenderness in the left upper quadrant of the abdomen. In addition, 500 ml of bile-colored fluid with small food particles was noted in the drainage tube. Barium X-ray revealed a gastric fistula in the upper gastrointestinal tract. Gastroscopy indicated infiltration of the drainage tube into the gastric cavity. No significant peritoneal effusion was observed, as revealed by abdominal ultrasound examination. These results confirmed the diagnosis of a gastric fistula secondary to perforation by the drainage tube. Following conservative treatment with antibiotics and total parenteral nutrition, the general condition of the patient improved significantly. The drainage tube was withdrawn progressively, as the amount of fluid being discharged was decreasing. Gastroenterography confirmed perforation closure and the tube was finally removed on post-operative day 44.

Overexpression of CD9 correlates with tumor stage and lymph node metastasis in esophageal squamous cell carcinoma.

OBJECTIVE: Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer deaths worldwide. CD9 has been reported to play a critical role in cell motility, growth and metastasis of multiple cancers. The present study investigated the clinicopathological features of CD9, and its biological characteristics in ESCC. METHODS: Fifteen normal esophageal tissue specimens, fifty-three ESCC adjacent tissues and one hundred and four ESCC tissues were included in this study. Using immunohistochemistry (IHC), the expression levels of CD9 were evaluated among different samples. And its clinicopathological parameters and its prognostic factors were analyzed. Western blotting was used to measure CD9 expression and colony formation was performed to determine the effect of CD9 on cell growth in ESCC TE-1 cells. RESULTS: Compared with normal esophageal tissues and tumor adjacent tissues, CD9 expression level is significantly higher in ESCC tissues. CD9 expression correlated with tumor stage (P=0.022) and lymph node metastasis (P=0.019) in ESCC patients. Furthermore, the small interfering RNA-mediated silencing of CD9 expression in TE-1 cells resulted in increased proliferation as evidenced by increased colony number and colony size. CONCLUSION: CD9 expression is upregulated in ESCC tissues and its expression is correlated with tumor stage and lymph node metastasis in ESCC patients. CD9 suppresses the proliferation of TE-1 cells. CD9 may present a potential in tumor progression in ESCC.

Applied anatomical study of the modified anconeus flap approach.

PURPOSE: Conventional surgical therapy for an intercondylar humerus fracture might result in multiple potential complications. Our study was conducted to evaluate the modified anconeus flap approach by adequately exposing the distal humeral articular surface, avoiding osteotomy of the olecranon and transection of the main part of the triceps brachial tendon from the olecranon. METHODS: Preparations of 20 upper limb specimens from adult cadavers were used in this study. We investigated the anatomical features of the distal tendon of the triceps brachii. Then, we designed a modified anconeus flap approach in cadaver specimens combined with the medial paratricipital approach, and we compared the extent of exposure of the distal humeral articular surface between the triceps-reflecting anconeus pedicle approach and this modified approach. RESULTS: The downward neurovascular bundles supplying the anconeus were located far from the intramuscular tendon of the triceps brachii. In addition, the medial head of the triceps was continuous with the anconeus near the lateral epicondyle of the humerus. These anatomical properties could assist in reducing adverse events in surgery. The percentage of the exposed humerus distal articular surface was 42.7% by applying the modified anconeus flap approach combined with the medial paratricipital approach. The modified anconeus flap approach can overcome the shortcomings of osteotomy or triceps transverse and fulfill reduction and internal fixation of most distal humerus intercondylar fractures. CONCLUSIONS: The present study has demonstrated a new approach for adequately exposing the distal humeral articular surface during surgery for an intercondylar humerus fracture. With this modified approach, osteotomy of the olecranon and the separation or transection of the main part of the triceps brachial tendon from the olecranon are not necessarily required. Therefore, we suggest that this novel approach could be applied as the primary surgical approach in intercondylar humerus fracture surgeries if the surgeons are familiar with the regional features of distal tendon of the triceps brachii and anconeus.

Upregulation of PAX2 promotes the metastasis of esophageal cancer through interleukin-5.

BACKGROUND/AIMS: This study investigated the clinical relevance and biological function of paired box gene 2 (PAX2) in esophageal squamous cell carcinoma (ESCC). METHODS/RESULTS: Results showed that PAX2 expression was significantly increased in tumor tissues and that its expression correlated with the ESCC stage (P = 0.001), lymph node metastasis (pN, P = 0.019) and lymphatic invasion (P = 0.005) in 120 ESCC tissue specimens by immunohistochemistry. Furthermore, PAX2 overexpression resulted in markedly reduced cell proliferation but increased metastasis capacity in ESCC TE-1 and Eca-109 cells. Knockdown of PAX2 expression with a short hairpin RNA confirmed a role in the promotion of metastasis in ESCC cells. mRNA microarray screening revealed that PAX2 overexpression affected multiple genes that function in multiple pathways. Interleukin-5 (IL-5), which was induced by PAX2 and has been shown to promote tumor metastasis, was further studied in greater detail. Two PAX2 binding sites were identified in the IL-5 promoter, and PAX2 was observed to stimulate IL-5 promoter activity and IL-5 expression in esophageal cancer cells. Chromatin immunoprecipitation (ChIP) confirmed the direct binding of PAX2 in the IL-5 promoter. The expression of PAX2 mRNA significantly correlated with that of IL-5 in normal esophageal and ESCC tissues. CONCLUSION: These findings demonstrate that PAX2 is overexpressed in esophageal carcinoma and IL-5 is identified as PAX2's effector for metastasis.

Ionizing irradiation inhibits keloid fibroblast cell proliferation and induces premature cellular senescence.

Keloids are one of the common refractory conditions in dermatology and aesthetic plastic surgery. The most effective treatment is superficial radiotherapy followed by surgical removal. The rate of recurrence is strongly associated with the total dose of ionizing irradiation, and the underlying mechanism remains unclear. In this study, we used primary keloid fibroblasts (KFb) isolated from patient samples to investigate the effects of X-ray radiation on cell proliferation, cell toxicity and cell cycle, as detected by CCK-8 assay kit and flow cytometer. In addition, we examined senescence-associated ß-galactosidase activity and the associated gene expression using real-time polymerase chain reaction and western blot in KFb exposed to X-ray radiation. X-ray radiation inhibited cell proliferation and induced cell senescence in KFb in a dose-dependent manner. Inhibition of cell proliferation and induction of cellular senescence were mediated by interruption of the cell cycle with an extended G0/G1 phase. Furthermore, the expressions of senescence-associated genes p21, p16 and p27 were upregulated both at mRNA and protein levels in KFb exposed to X-ray radiation. Taken together, our data indicate that X-ray radiation may prevent the recurrence of keloids by controlling fibroblast proliferation, arresting the cell cycle and inducing premature cellular senescence.

Relationships of common polymorphisms in IL-6, IL-1A, and IL-1B genes with susceptibility to osteoarthritis: a meta-analysis.

Observational and experimental studies have arrived at inconsistent conclusions about whether common polymorphisms in IL-6, IL-1A, and IL-1B genes are associated with an increased risk of osteoarthritis (OA). Therefore, we undertook a comprehensive meta-analysis to more systematically summarize the relationships of IL-6, IL-1A, and IL-1B genetic polymorphisms with susceptibility to OA. We screened the PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, China BioMedicine (CBM), and China National Knowledge Infrastructure (CNKI) databases up to 31 March 2014. We used STATA software to analyze statistical data. Odds ratios (ORs) and their corresponding 95 % confidence intervals (95 % CIs) were calculated. Seventeen independent case-control studies were included in this meta-analysis with a total number of 7,491 subjects, comprised of 3,293 OA patients and 4,729 healthy controls. Our results indicate that IL-6, IL-1A, and IL-1B genetic polymorphisms are statistically correlated with an increased risk of OA under the allele and dominant models. According to a subgroup analysis based on disease, a higher frequency of IL-6 genetic polymorphisms was observed among knee OA and hand OA patients, but not among hip OA and DIP OA patients. A higher frequency of IL-1A genetic polymorphisms were found among hip OA patients, hand OA, hip OA and DIP OA patients. Furthermore, we observed a higher IL-1B polymorphism frequency among knee OA and hip OA patients, but not among hand OA patients. Our findings provide evidence that IL-6, IL-1A, and IL-1B genetic polymorphisms may be correlated with susceptibility to OA.

[Isolation and characterization of the first strain of Helicobacter hepaticus in China].

Helicobacter hepaticus is nongastric helicobacter that can reside in the hepatobiliary and intestinal systems of many animal hosts, leading to proliferative hepatitis, hepatocellular carcinoma, typhlitis, and colonitis. In this study, the intestinal mucosa was isolated from BALB/c mice to prepare tissue homogenate and spread onto selective C jejuni blood agar plates for incubation in the presence of trimethoprim, vancomycin, and polymyxin at 37 degrees Celsius; under microaerobic conditions in vented jars containing 5% O2, 10%CO2, and 85% N2. The bacteria were identified morphologically and biochemically. Gene sequence analysis of the 16s rRNA confirmed the presence of Helicobacter hepaticus, and the success in isolating this bacteria may have significant implications for studies of nongastric helicobacter.

[Immunization with catalase and UreB two-valence vaccine for preventing Helicobacter pylori infection in mice].

OBJECTIVE: To investigate the effects of the two-valence vaccine consisting of Helicobacter pylori (H. pylori) catalase and urease subunit UreB in preventing H. pyloriinfection in mice. METHODS: C57BL/6 mice were divided into 7 groups and immunized with intragastric administration of catalase and UreB (both 100 microg) plus cholera toxin (CT, 2 microg), catalase (100 microg) plus CT (2 microg), UreB (100 microg) plus CT (2 microg), catalase (100 microg), UreB (100 microg), CT (2 microg), or PBS, respectively, once a week for 4 consecutive weeks. Two weeks after the last immunization, all the mice were challenged by live H. pylori, and sacrificed 4 weeks after the challenge to obtain the gastric mucosa samples for detecting H. pylori using semi-quantitative bacterial culture assay. RESULTS: The total protection rate in mice immunized with the two-valence vaccine, single-valence vaccine of catalase, and single-valence vaccine of UreB was 83.3% (20/24), 41.7% (10/24) and 54.2% (13/24), respectively, and the rate in the other 4 groups were all 0. The H. pyloricolony density in mice with vaccination was significantly lower than that of other 4 groups (P<0.05). The total protection rate and H. pylori colony density differed significantly between the two-valence vaccination group and the single-valence vaccination groups (P<0.05). CONCLUSION: The two-valence vaccine consisting of catalase, UreB and adjuvant has better immunoprotective effects than the single-valence vaccines.

Pathogenicty and immune prophylaxis of cag pathogenicity island gene knockout homogenic mutants.

AIM: To clarify the role of cag pathogenicity island (cagPAI) of Helicobacter pylori (H pylori ) in the pathogenicity and immune prophylaxis of H pylori infection. METHODS: Three pairs of H pylori including 3 strains of cagPAI positive wildtype bacteria and their cagPAI knockout homogenic mutants were utilized. H pylori binding to the gastric epithelial cells was analyzed by flow cytometry assays. Apoptosis of gastric epithelial cells induced by H pylori was determined by ELISA assay. Prophylaxis effect of the wildtype and mutant strains was compared by immunization with the sonicate of the bacteria into mice model. RESULTS: No difference was found in the apoptasis between cagPAI positive and knockout H pylori strains in respective of the ability in the binding to gastric epithelial cells as well as the induction of apoptosis. Both types of the bacteria were able to protect the mice from the infection of H pylori after immunization, with no difference between them regarding to the protection rate as well as the stimulation of the proliferation of splenocytes of the mice. CONCLUSION: The role of cagPAI in the pathogenicity and prophylaxis of H pylori infection remains to be cleared.

Proteasome-dependent degradation of cytochromes P450 2E1 and 2B1 expressed in tetracycline-regulated HeLa cells.

The degradation of ethanol-inducible cytochrome P450 2E1 (CYP2E1) and phenobarbital-inducible cytochrome P450 2B1 (CYP2B1) expressed in tetracycline (Tc)-inducible HeLa cell lines was characterized. A steady-state pulse-chase analysis was used to determine a half-life of 3.8 h for CYP2E1 while the half-life of CYP2B1 was 2.3-fold greater in the same cell line. In contrast, NADPH cytochrome P450 reductase which is constitutively expressed in Tc-HeLa cells had a half-life of about 30 h. Lactacystin and other selective proteasome inhibitors including N-benzyloxycarbonyl-leucyl-leucyl-leucinal (MG132) and N-benzyloxycarbonyl-L-leucyl-L-leucyl-L-norvalinal (MG115) significantly inhibited both CYP2E1 and CYP2B1 degradation. The turnover of CYP2E1 was slightly inhibited by calpain inhibitors while CYP2B1 turnover was not altered. Inhibitors of lysosomal proteolysis had no effect on the degradation of either protein. Treatment of cells with brefeldin A did not alter the degradation of either P450 which suggested the degradation occurred in the endoplasmic reticulum (ER). Even in the presence of proteasome inhibitors high molecular weight ubiquitin conjugates were not observed. Mutagenesis of two putative ubiquitination sites (Lys 317 and 324) did not alter the degradation of CYP2E1. The role of ubiquitination in the degradation of CYP2E1 was also examined in a Chinese hamster mutant cell line E36ts20 that contains a thermolabile ubiquitin-activating enzyme (E1). The turnover of CYP2E1 was not significantly different at the nonpermissive temperature in the ts20 when compared to the control E36 cells. Furthermore, the addition of the hsp90 inhibitors geldanamycin, herbimycin, and radicicol had no effect on the turnover of CYP2E1, differentiating the degradation of CYP2E1 from other substrates for proteasome-dependent degradation.

[Regulation of Fas expression in gastric epithelium: one of the auto-immune mechanisms of Helicobacter pylori pathogenesis].

OBJECTIVE: To investigate the pathogenic mechanism of Helicobacter pylori (H.pylori)-mediated gastric epithelial cell damage. METHODS: Fas expressions in gastric epithelial cell lines and freshly isolated gastric epithelial cells with or without H.pylori infection were evaluated by flow cytometry. The modulation of Fas expression in gastric epithelial cells by H.pylori or by Th1 cytokines present in H.pylori-infected gastric mucosa was assessed in vitro. The function of Fas expressed by the gastric epithelial cells to induce cell apoptosis was determined by enzyme-linked immunosorbent assay (ELISA) after incubation of the cells with anti-Fas antibody. RESULTS: All of the three gastric epithelial cell lines, AGS, N87 and kato-III, expressed detectable Fas protein when examined by flow cytometry. The percentage of positive cells and the amount of Fas protein on cell surface were larger in freshly isolated gastric epithelial cells with H.pylori infection than in uninfected cells (P<0.05). H. pylori alone or in combination with Th1 cytokines (IFN-gamma and TNF-alpha) significantly increased the expression of Fas in gastric epithelial cell lines in vitro. After incubation with IgM anti-Fas mAb, Fas-bearing gastric epithelial cells underwent apoptosis, and this effect of Fas was enhanced by IFN-gamma. CONCLUSION: Th1 cells accumulated in the gastric mucosa during H.pylori infection is involved in the damage of gastric epithelium through the modulation of Fas/Fas ligand interaction.