Percutaneous Placement of Self-expandable Metallic Biliary Stents in Malignant Extrahepatic Strictures: Indications of Transpapillary and Suprapapillary Methods

Objective

To compare the efficacy of suprapapillary and transpapillary methods of transhepatic biliary metallic stent placement in malignant biliary strictures and to specify the indications of each method applied.

Materials and Methods

Stents were placed in 59 patients. Strictures were categorized as type A (within 3 cm of the ampulla, n = 27), type B (over 3 cm from ampulla, n = 7), type C (within 3 cm of the bending portion, n = 9), or type D (over 3 cm above the bending portion, n=16). The stenting method was suprapapillary in 34 cases and transpapillary in 25. The rates of initial and long-term patency and of early recurrence were compared.

Results

Initial patency rates for the suprapapillary and transpapillary methods were 1/7 (14.3%) and 20/20 (100%) respectively for type A (p < 0.0001), 4/5 (80.0%) and 2/2 for type B, 3/7 (42.9%) and 2/2 for type C, and 15/16 (93.8%) and 0/0 for type D. Early recurrence rates were 7/30 (23.3%) using the suprapapillary method and 4/29 (13.8%) using the transpapillary method (p = 0.51). The long-term patency rate did not differ significantly according to either type (p = 0.37) or method (p = 0.62).

Conclusion

For good initial patency, the transpapillary method is recommended for strictures of the distal extrahepatic duct near the ampulla and just above the bending portion. Long-term patency is not influenced by the stenting method employed.     

A rice chloroplast transit peptide sequence does not alter the cytoplasmic localization of sheep serotonin N‐acetyltransferase expressed in transgenic rice plants

Ectopic overexpression of melatonin biosynthetic genes of animal origin has been used to generate melatonin‐rich transgenic plants to examine the functional roles of melatonin in plants. However, the subcellular localization of these proteins expressed in the transgenic plants remains unknown. We studied the localization of sheep (Ovis aries) serotonin N‐acetyltransferase (OaSNAT) and a translational fusion of a rice SNAT transit peptide to OaSNAT (TS:OaSNAT) in plants. Laser confocal microscopy analysis revealed that both OaSNAT and TS:OaSNAT proteins were localized to the cytoplasm even with the addition of the transit sequence to OaSNAT. Transgenic rice plants overexpressing the TS:OaSNAT fusion transgene exhibited high SNAT enzyme activity relative to untransformed wild‐type plants, but lower activity than transgenic rice plants expressing the wild‐type OaSNAT gene. Melatonin levels in both types of transgenic rice plant corresponded well with SNAT enzyme activity levels. The TS:OaSNAT transgenic lines exhibited increased seminal root growth relative to wild‐type plants, but less than in the OaSNAT transgenic lines, confirming that melatonin promotes root growth. Seed‐specific OaSNAT expression under the control of a rice prolamin promoter did not confer high levels of melatonin production in transgenic rice seeds compared with seeds from transgenic plants expressing OaSNAT under the control of the constitutive maize ubiquitin promoter.     

Generation of an attenuated Salmonella-delivery strains expressing adhesin and toxin antigens for progressive atrophic rhinitis,and evaluation of its immune responses in a murine model

An expression/secretion plasmid containing genes encoding the FimA, CP39, PtfA, ToxA and F1P2 antigens associated with porcine pneumonic pasteurellosis and progressive atrophic rhinitis (PAR) was constructed and harbored in an attenuated Salmonella Typhimurium, which was used as the vaccine candidate. The immune responses induced by this delivery strain were investigated in a murine model. Each antigen secreted from the delivery strain was confirmed by Western blot analysis. Thirty BALB/c mice were divided equally into two groups; group A were intranasally inoculated with the mixture of the five delivery strains, and group B were inoculated with sterile PBS. In group A, all antigen-specific serum IgG were significantly increased compared to those of group B from the 2nd week post-inoculation (WPI) till the 8th WPI. All antigen-specific mucosal IgA in group A were also significantly greater than those of group B. In addition, the significant splenic lymphocyte proliferative responses, the elevations of CD3⁺CD4⁺, CD3⁺CD8⁺ and B-cell populations, and the induction of IFN-γ expression in group A were observed. In conclusion, the mixture of five delivery strains expressing specific antigen for these diseases was found to be capable of inducing significant humoral and cellular immune responses.     

Elevated production of melatonin in transgenic rice seeds expressing rice tryptophan decarboxylase

A major goal of plant biotechnology is to improve the nutritional qualities of crop plants through metabolic engineering. Melatonin is a well‐known bioactive molecule with an array of health‐promoting properties, including potent antioxidant capability. To generate melatonin‐rich rice plants, we first independently overexpressed three tryptophan decarboxylase isogenes in the rice genome. Melatonin levels were altered in the transgenic lines through overexpression of TDC1, TDC2, and TDC3; TDC3 transgenic seed (TDC3‐1) had melatonin concentrations 31‐fold higher than those of wild‐type seeds. In TDC3 transgenic seedlings, however, only a doubling of melatonin content occurred over wild‐type levels. Thus, a seed‐specific accumulation of melatonin appears to occur in TDC3 transgenic lines. In addition to increased melatonin content, TDC3 transgenic lines also had enhanced levels of melatonin intermediates including 5‐hydroxytryptophan, tryptamine, serotonin, and N‐acetylserotonin. In contrast, expression levels of melatonin biosynthetic mRNA did not increase in TDC3 transgenic lines, indicating that increases in melatonin and its intermediates in these lines are attributable exclusively to overexpression of the TDC3 gene.     

Clinicopathological significance of vascular endothelial growth factor-C and cyclooxygenase-2 in esophageal squamous cell carcinoma

BACKGROUND: Vascular endothelial growth factor-C (VEGF-C) is a specific growth factor of lymphatics, which is known to play some role in tumor growth and metastasis to lymph nodes and distant organs in various malignancies. The purpose of the present study was to investigate the expression of VEGF-C in human esophageal squamous cell carcinomas (ESCC) to elucidate its role in tumor progression and lymph node metastasis. Another aim of the study was to investigate the relation between VEGF-C and cyclooxygenase-2 (COX-2) in ESCC. METHODS: The expression of VEGF-C and COX-2 in ESCC was evaluated in 13 endoscopic mucosal resection specimens and in 21 surgical specimens by immunohistochemical staining. Clinical data were obtained from medical records. RESULTS: The degree of VEGF-C expression increased as the depth of primary tumor progressed (r = 0.521, P = 0.002), the stage progressed (r = 0.572, P < 0.001), and the degree of COX-2 expression increased (r = 0.387, P = 0.024). The VEGF-C positive rate was different between early cancers in which regional lymph node metastasis was thought to be absent and advanced cancers in which regional lymph node metastases were confirmed after surgery (20.0% vs 100.0%; P < 0.001). CONCLUSIONS: The VEGF-C expression in ESCC is related to COX-2 expression, and VEGF-C is also associated with the depth of primary tumor, the stage, and probably lymph node metastasis. Thus the investigation of VEGF-C expression in ESCC may assist in management planning.     

Clinical significance of distal colon polyps for the prediction of an advanced proximal neoplasm: the KASID prospective multicenter study

Background/aims The possibility of proximal lesion without distal polyps is a weak point of sigmoidoscopic colon cancer screening, but the clinical significance of distal findings for advanced proximal neoplasm (APN) is uncertain. The aim of this study was to assess the significance of a distal finding as a predictor of APN. Materials and methods Asymptomatic patients ≥50 years old were enrolled from among patients who underwent polypectomy at 11 tertiary medical centers during the Korean Association for the Study of Intestinal Disease prospective study conducted between July 2003 and March 2004. Polyps located distal to the splenic flexure were defined as distal polyps. An advanced neoplasm was defined as a polyp of ≥10 mm in size, and/or with villous features, and/or with high-grade dysplasia, or invasive cancer. Age, gender, and distal polyp size, appearance, and histology were analyzed as risk factors of APN. The sensitivity and positive predictive value of distal polyps for APN were calculated. Results Data from 826 patients were analyzed. Mean patient age was 60.1 years (range 50–86), and 71.3% were men. APN was found in 98 patients, and 45 (45.9%) patients had no distal polyps. Risk factors of APN were a male gender, distal polyp size, and an advanced distal neoplasm. Sensitivities of a distal polyp of ≥10 mm and of an advanced distal neoplasm for APN were both 38.8% with positive predictive values of 13.3 and 14.4%, respectively. Conclusions Although distal colon findings were found to be helpful for predicting APN in asymptomatic patients aged ≥50 years, APN without distal polyps requires careful consideration.