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Currently, there are no FDA approved medications for treatment of cocaine addiction underscoring the dire need to develop such a product. There is an accumulating body of evidence that l-tetrahydropalmatine (l-THP), a non-selective dopamine antagonist, can be used for the treatment of cocaine addiction. Indeed, the FDA recently approved its usage in a Phase I study in cocaine abusers and it was indispensable to develop a simple and sensitive method for the simultaneous determination of l-THP and cocaine in human plasma. We developed a UPLC-FLD method for quantitation of these molecules using an ACQUITY BEH C18 column (2.1mm×50mm, 1.7µm) and a mobile phase that consisted of 10mM ammonium phosphate (pH=4.75), methanol, and acetonitrile (v:v:v, 78:16:6). Venlafaxine was used as the internal standard while hexane was used for the liquid-liquid extraction. The flow rate was 0.4mL/min with fluorescence detection using an excitation wavelength of 230nm and emission detection wavelength of 315nm. This method was selective, linear and sensitive with a lower limit of quantification of 2.5ng/mL for both cocaine and l-THP. The intra-day precision of cocaine and l-THP was <9.50% while the accuracy was <4.29%. The inter-day precision of cocaine and l-THP was <9.14%, and the accuracy was <12.49%. The recovery for cocaine and l-THP ranged from 43.95 to 50.02% and 54.65 to 58.31%, respectively. In comparison to forty reported cocaine quantitation methods this method is simple, sensitive and cost-effective and can be used for simultaneous quantitation of l-THP and cocaine. This method meets the FDA guidelines and can be used in current and future clinical studies. [ABSTRACT FROM AUTHOR]

The reason why delayed RBC engraftment and pure red cell aplasia (PRCA) develop only in some but not all recipients of major ABO-incompatible hematopoietic stem cell transplantation (HSCT) remains elusive and the underlying mechanisms are not fully understood. Understanding how incompatible erythroid blood group antibodies (Abs) interact with ABH antigens (Ags) of grafts, and investigating how to induce artificially accommodation of grafts are of obvious importance in transplantation immunology. The effects of anti-H on proliferation, apoptosis, and α-(1,2)-fucosyltransferase gene (FUTJ) expression in erythroid differentiated K562 cells were analyzed by the MTT assay, Annexin V/PI staining, and quantitative RT-PCR method. The growth of erythroid differentiated K562 cells was significantly suppressed when anti-H dilution was ≤1:8 (P< 0.001, as compared with 1:16). Under the complement-free culture conditions, the apoptotic ratio of erythroid differentiated K562 cells was significantly increased when anti-H dilution was ≤1:16 (P<0.05, as compared with 1:32). The apoptosis was not only closely associated with anti-H dilution (F = 138.991, P<0.001 ), but also correlated with treated time (F = 583.249, P<0.001 ), which indicated typical dose- and time-dependent effects. Under the complement-free culture conditions, the FUT1 mRNA expression level was also suppressed when anti-H dilution was ≤1:16 (P<0.05, as compared with 1:32), which also manifested in typical dose-dependent (F= 130.356, P<0.001) and time-dependent (F= 1432.00, P<0.001) effects. The results confirm that anti-H can trigger apoptosis and down-regulate FUT1 expression in erythroid differentiated K562 cells without complement mediation. The findings suggest that anti-H could accommodate grafts through triggering apoptosis and down-regulating Futl expression to reduce ABH antigens. [ABSTRACT FROM AUTHOR]