After Sinomenine 27 ?M was given, the contractibility was decreased to 51?11% (SD) and dT/dt max to 50?14% (SD). The automaticity induced by epinephrine was inhibited. Sinomenine (2.7-270 ?M) caused a concentration-dependent prolongation in the functional period. The amplitude of contraction and the heart rate in the right auricle was also inhibited. The results indicate that sinomenine may be antogonistic to both Ca~(++) influx and inward Na~(++) current.

The effects of sinomenine (Sin) on isoprenaline and hist ami no dose-response relationships and calcium-mediated positive chronotro-pic time-response relationship were studied in isolated guinea-pig ri^lil atritui. Sin shifted isoprenaline and histamine doseresponse cuives to the right non-parallely and depressed their maximum and produced a noncompetitive antagonism. The pD'2 values were 3.48+ 0.08 and 3.63+0.04, respectively. It was different from B-receptor blocker propranolol and H2-receptor blocker cimetidinc. Sin as well as verapamil antagonized the positive chronotropic response to CaCl2. These results suggested that the negative chrouotropic effects of Sin did not result from blocked |3-and H2-receptor, but probably from antagonizing Ca2+ channel.

Objective To learn the effect of different combination model between irradiation and cisplatin or lobaplatin on the radiosensitization of xenographt tumor in mice.Methods Seventy C57BL/6 mice with Lewis lung carcinoma were randomly divided into fourteen groups.Then a single intravenous bolus injection of 10 mg/kg either cisplatin or lobaplatin was given.Tumor tissues were collected at the indicated times of 0.5 h, 2.0 h, 4.0 h, 24.0 h, 48.0 h, 72.0 h, and 96.0 h.The platinum levels were determined by inductively coupled plasma-mass spectrometry.Eighty tumor-bearing mice were randomly divided into 10 groups, including a blank control group, a irradiation group, two drug treatment groups and 6 combined treatment groups.The tumors were irradiated at 1 h, 24 h or 72 h after either cisplatin or lobaplatin injection.The tumor size of the groups was compared.Results The concentrations of cisplatin and lobaplatin in tumors rapidly reached 4.78 μg/g and 2.79 μg/g (t=3.82,P=0.005), respectively, then declined rapidly to 3.39 μg/g and 0.99 μg/g (t=9.10,P=0.000) at 4 h, 1.41 μg/g and 0.23 μg/g (t=3.70,P=0.006) at 96 h, respectively.The tumor growth among the three groups of irradiation at 1 h, 24 h or 72 h after cisplatin was similar, which was slower than the blank control group, the irradiation group and the cisplatin treatment group.At the 15th day, the relative volume of tumor in the three combined treatment groups were 4.73, 5.52 and 2.15(F=0.84,P=0.451), While was 16.63(F=10.50,P=0.000) in the blank control group, 10.34(F=3.12,P=0.046) in the irradiation group, and 12.80(F=8.06,P=0.001) in the cisplatin treatment group, respectively.The tumor growth among the three groups of irradiation at 1 h, 24 h or 72 h after lobaplatin was also similar, which was slower than the blank control group, the irradiation group and the lobaplatin treatment group.At the 15th day, the relative volume of tumor in the three combined treatment groups were 3.49, 4.90 and 3.86(F=0.32,P=0.727), While was 16.63(F=15.21,P=0.000) in the blank control group, 10.34(F=4.12,P=0.016) in the irradiation group, and 14.28(F=10.67,P=0.000) in the lobaplatin treatment group, respectively.The sensitizing enhancement ratio (SER) at 1 h, 24 h and 72 h after the injection were 2.13, 2.03 and 3.45 of cisplatin, and 2.53, 2.00 and 2.50 of lobaplatin, respectively.Conclusions After intravenous bolus injection, the cisplatin concentration in the tumor can be kept at least 96 hours, which results in a persistent radiosensitizing effect.Lobaplatin and cisplatin have similar anti-tumor and radiosensitizing effect.

In this paper, adriamycin-carboxymethyldextran magnetic nanoparticles (ADR-CMD MNPs) were prepared. After i.v. administration in mice, acute toxicity, cumulative toxicity and the distribution profiles of heart were studied both for free adriamycin(ADR) and ADR-CMD MNPs. The results showed conjugation with CMD MNPs, the acute toxicity of ADR was decreased significantly, the LD50 value of ADR-CMD MNPs was 5.06 times as high as that of the free ADR. Altogether, the cumulative toxicity of conjugate MNPs is significantly decreased as expressed by the mortality, the loss for both weight and leucocyte after repeated injection. Tissue distribution studies show the reduced cardiac uptake of ADR after i.v. which possibly contributes to minimizing the cardiotoxic effect of ADR.
Animals ; Dextrans ; Doxorubicin ; administration & dosage ; pharmacokinetics ; toxicity ; Drug Carriers ; Drug Delivery Systems ; Female ; Injections, Intravenous ; Magnetics ; Male ; Mice ; Myocardium ; metabolism ; Tissue Distribution