The Role of κ Opioid Receptor in Brain Ischemia.

OBJECTIVES: Our previous studies indicated that highly selective κ opioid receptor agonists could protect the brain, indicating an important role of κ opioid receptor agonist in brain ischemia. In this study, we investigated the role and related mechanisms of κ opioid receptor agonists in brain ischemia in a middle cerebral artery occlusion mouse model. DESIGN: Animal model. SETTING: Laboratory. SUBJECTS: The middle cerebral artery occlusion model was established by 120 minutes of ischemia followed by 24-hour reperfusion in male adult mice. INTERVENTIONS: Various doses of salvinorin A, a highly selective and potent κ opioid receptor agonist, were administered intranasally 10 minutes after initiation of reperfusion. Norbinaltorphimine (2.5 mg/kg, IP) as a κ opioid receptor antagonist was administered in one group before administration of salvinorin A (50µg/kg) to investigate the specific role of κ opioid receptor. MEASUREMENTS AND MAIN RESULTS: Infarct volume, κ opioid receptor expression, and Evans blue extravasation in the brain, and neurobehavioral outcome were determined. Immunohistochemistry and western blot were performed to detect the activated caspase-3, interleukin-10, and tumor necrosis factor-α levels to investigate the role of apoptosis and inflammation. κ opioid receptor expression was elevated significantly in the ischemic penumbral area compared with that in the nonischemic area. Salvinorin A reduced infarct volume and improved neurologic deficits dose-dependently. Salvinorin A at the dose of 50 µg/kg reduced Evans blue extravasation, suggesting reduced impairment of the blood-brain barrier and decreased the expression of cleaved caspase-3, interleukin-10, and tumor necrosis factor-α in the penumbral areas. All these changes were blocked or alleviated by norbinaltorphimine. CONCLUSIONS: κ opioid receptors were up-regulated and played a critical role in brain ischemia and reperfusion. κ opioid receptor activation could potentially protect the brain and improve neurologic outcome via blood-brain barrier protection, apoptosis reduction, and inflammation inhibition.

Detection of hepatitis B virus A1762T/G1764A mutant by amplification refractory mutation system

OBJECTIVE: To study the role of hepatitis B virus with A1762T/G1764A double mutation in liver cirrhosis and hepatocellular carcinoma, and create a sensitive, fast, accurate assay for detection of A1762T/G1764A double mutation. METHODS: We developed an accurate and fast real-time amplification refractory mutation system to detect A1762T/G1764A double mutation. Cloned hepatitis B virus genome was used as a control. Assay sensitivity was determined by serial dilution and mixed template experiments. Specificity was determined by cross experiments with wild and mutant hepatitis B virus. Fifty clinical samples were tested by the real-time amplification refractory mutation system and the results were compared with sequencing. RESULTS: The real-time amplification refractory mutation system had a sensitivity of 100 copies of virus with these mutations, and 0.1% weak population virus with double mutation could be found in mixtures. A total of 50 randomly collected clinical samples were detected by real-time amplification refractory mutation system, and the results were consistent with those by DNA sequencing. Hepatitis B virus genotype C was more prevalent in 39 of 50 samples than genotype B (11 samples), and about 75% of genotype C carried a double mutation compared to 45% of genotype B. However, the percentage of A1762T/G1764A double mutation in hepatitis B e antigen-negative (58.3%) samples was almost the same as in hepatitis B e antigen-positive (61%) samples. CONCLUSION: The real-time amplification refractory mutation system is sensitive and specific for detection of hepatitis B virus double mutation. .

Detection of hepatitis B virus A1762T/G1764A mutant by amplification refractory mutation system.

OBJECTIVE: To study the role of hepatitis B virus with A1762T/G1764A double mutation in liver cirrhosis and hepatocellular carcinoma, and create a sensitive, fast, accurate assay for detection of A1762T/G1764A double mutation. METHODS: We developed an accurate and fast real-time amplification refractory mutation system to detect A1762T/G1764A double mutation. Cloned hepatitis B virus genome was used as a control. Assay sensitivity was determined by serial dilution and mixed template experiments. Specificity was determined by cross experiments with wild and mutant hepatitis B virus. Fifty clinical samples were tested by the real-time amplification refractory mutation system and the results were compared with sequencing. RESULTS: The real-time amplification refractory mutation system had a sensitivity of 100 copies of virus with these mutations, and 0.1% weak population virus with double mutation could be found in mixtures. A total of 50 randomly collected clinical samples were detected by real-time amplification refractory mutation system, and the results were consistent with those by DNA sequencing. Hepatitis B virus genotype C was more prevalent in 39 of 50 samples than genotype B (11 samples), and about 75% of genotype C carried a double mutation compared to 45% of genotype B. However, the percentage of A1762T/G1764A double mutation in hepatitis B e antigen-negative (58.3%) samples was almost the same as in hepatitis B e antigen-positive (61%) samples. CONCLUSION: The real-time amplification refractory mutation system is sensitive and specific for detection of hepatitis B virus double mutation.