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ABSTRACT: Among the various possible causes for drug interactions, pharmacokinetic factors such as inhibition of drug-metabolizing enzymes and transporters, especially cytochrome P450 (CYP) isoenzymes and P-glycoprotein (P-gp), are regarded as the most frequent and clinically important. Limonin is a widely used dietary supplement and one of the most prevalent citrus limonoids, which are known to have inhibitory effects on CYPs and P-gp. In this study, the in vitro inhibitory effects of limonin on the major human CYP isoenzymes (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4) activities in human liver microsomes were examined using liquid chromatography-tandem mass spectrometry. The inhibitory effects of limonin on P-gp activity in a human metastatic malignant melanoma cell line WM-266-4 were examined using a calcein-AM fluorometry screening assay. It demonstrates that limonin has negligible inhibitory effects on human CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and P-gp. However, potent inhibition of CYP3A4 by limonin is observed with IC50 values of 6.20 μM (CYP3A4/testosterone) and 19.10 μM (CYP3A4/midazolam). This finding has important implications with regard to food-drug interactions between limonin and several narrow therapeutic index drugs that are metabolized by CYP3A4.
Toxicology in Vitro 12/2011; 25(8):1828-33. · 2.78 Impact Factor
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ABSTRACT: Huanglian (Rhizoma Coptidis) as a popular herb has been used for the treatment of various diseases such as diarrhea, eye inflammation and women's abdominal ailments. Alkaloids are considered to be responsible for its pharmacological effects. In this investigation, Huanglian and its six alkaloids (coptisine, epiberberine, berberine, jateorrhizine, palmatine and magnoflorine) were systematically evaluated for their inhibition of six cytochrome P450 isoforms (CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6 and CYP3A4) in human liver microsomes by the LC-MS/MS method. Huanglian showed the strongest inhibition of CYP2D6, followed by CYP1A2 and CYP3A4_T. The IC₅₀ values were 5.8 µg/mL, 36.8 µg/mL and 59.2 µg/mL, respectively. Of the constituents tested, coptisine and epiberberine showed strong inhibition of CYP2D6 with IC₅₀ values of 4.4 µM and 7.7 µM; berberine, jateorrhizine and palmatine showed weak inhibition of CYP2D6 with IC₅₀ values of 45.5 µM, 49.4 µM and 92.6 µM, respectively; jateorrhizine showed moderate inhibition of CYP3A4_T with an IC₅₀ value of 13.3 µM; coptisine showed weak inhibition of CYP1A2 with an IC₅₀ value of 37.3 µM. In addition, activation was observed in coptisine/CYP2C9 and palmatine/CYP2C9/CYP2C19. Other CYP450 isoforms were not affected markedly by the six alkaloids. In conclusion, Huanglian showed in vitro inhibition of CYP2D6, the inhibition might be contributed mostly by protoberberine alkaloids, especially coptisine and epiberberine. Herb-drug interactions may occur through the CYP2D6 inhibition.
Phytotherapy Research 03/2011; 25(11):1660-5. · 2.09 Impact Factor
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ABSTRACT: To discuss surgical treatment of right colon carcinoma of hepatic flexure invading the duodenum.
Sixty-five patients with right colon carcinoma of hepatic flexure invading the duodenum, treated in our department from 1987 to 2007, were included in this study. Their clinicopathological data were retrospectively reviewed and analyzed. All the cases were divided into three types (local invasion, regional invasion, and cancer with internal fistula) according to duodenal defect, including local invasion (< 2.0 cm), wide invasion (> 2.0 cm) and the presence of internal fistula.
25 patients with local invasion underwent en bloc resection of the duodenal wall. Pedicled ileal flap was used to cover the large duodenal defect measuring 2.0 - 3.0 cm in 5 patients. Dudenojejunostomy was used to reconstruct the large defect measuring more than 5 cm in 3 patients. Conservative resection of right-sided colon was performed in 18 patients with wide invasion. 4 patients underwent pancreaticoduodenectomy combined with right hemicolectomy for colon cancer involving the pancreatic head. 10 underwent duodenal diverticularization. One patient with anastomotic leakage healed within 3 weeks. Other patients were cured without postoperative complications. The total 3-year and 5-year survival rates after surgery were 53.8% and 9.2%, respectively.
The surgical procedure to be performed is usually decided according to the cancer location, extent, and duodenal defect and invasion, which are important for prolonging life time, improving of quality of life and prognosis in these patients.
Zhonghua zhong liu za zhi [Chinese journal of oncology] 11/2009; 31(11):873-6.
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ABSTRACT: To summarize the experience in the diagnosis and surgical treatment of carcinoid tumors of the appendix.
From 1972 to 2006, 64 patients with carcinoid tumors of the appendix received surgical treatment in our hospitals. The clinical data of those patients were retrospectively analyzed.
Of the 64 cases, only 6 cases (9.4%) were correctly diagnosed preoperatively, while 58 (90.6%) not confirmed, with a misdiagnosis rate of 90.6%. All patients underwent surgical treatment, including appendectomy in 54, ileocecectomy in 4, right hemicolectomy in 2 and right hemicolectomy with regional lymph node dissection in 4 cases. The operation modes were determined according to the doctor's judgments based on the age of the patients, the nature, size, location, infiltration depth and lymph node metastasis of the tumors. Of the 64 patients, 58 were followed up with a longest follow-up period of 13 years, while 6 lost follow-up. Fifty-seven of those were still surviving, only one died of liver metastasis at 13 years after operation.
Carcinoid tumor of the appendix is rare with a high rate of misdiagnosis before operation. Surgical resection is the only effective treatment for this disease and proper operation mode is the key to achieve good survival.
Zhonghua zhong liu za zhi [Chinese journal of oncology] 08/2008; 30(7):538-40.
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ABSTRACT: To investigate the expressions and clinical implications of kruppel-like factor 6(KLF-6) and APC in human colorectal carcinoma.
The expressions of KLF-6 and APC in tumor and normal tissues from 32 patients with colorectal carcinoma were investigated by RT-PCR and immunohistochemical technique.
The expression rates of KLF-6 and APC mRNA were 37.5% and 34.3% in tumor tissue, 96.9% and 93.8% respectively in normal tissues (both P< 0.05). The expression rates of KLF-6 and APC protein were 28.1% and 25.0% in colorectal carcinomas, 81.3% and 84.43% respectively in normal tissues (both P< 0.05). There was a significant correlation between the expressions of KLF-6 and APC in colorectal carcinomas (P < 0.05). The expressions of KLF-6 and APC were significantly correlated with tumor differentiation, depth of infiltration, lymph node metastasis and clinical stage (P< 0.05).
Down-regulations of KLF-6 and APC might play an important role in the carcinogenesis, development, metastasis of human colorectal carcinoma.
Zhonghua wei chang wai ke za zhi = Chinese journal of gastrointestinal surgery 10/2006; 9(5):429-32.
