[Chemical constituents of the leaves of Crataegus pinnatifida Bge. var. major N. E. Br]

Compounds were isolated from the aqueous extract of the leaves of Crataegus pinnatifida var. major and seven of them were identified as 2-(4-hydroxybenzyl)malic acid, quercetin, hyperin, vitexin, rhamnosylvitexin, diethylamine hydrochloride and sorbitol respectively by UV, IR, NMR, MS, some chemical techniques by comparison with the standard spectra of known compounds.

[Establishment of a malignant astrocytoma cell line TJ-8510 and its characterization]

A malignant astrocytoma cell line TJ-8510 derived from temporoparietal astrocytoma Grade III was established. At present, it has survived for more than 34 months passaging through 220 generations. According to its features in cell kinetics, cytogenetics, morphology, biochemistry and heterotransplantation, it was still identified as malignant astrocytoma. This cell line may be useful in further research on glioma.

Actions of dendrotoxin on K+ channels and neuromuscular transmission in Drosophila melanogaster, and its effects in synergy with K+ channel-specific drugs and mutations

The blockade of K+ channels and enhancement of neuromuscular transmission by dendrotoxin (DTX), a convulsant peptide from mamba snake venom, were examined in normal and mutant larval preparations of Drosophila. Two-microelectrode voltage-clamp experiments showed that DTX reduced the transient K+ current, IA, in muscle membrane. This effect was suppressed by raising the Mg2+ concentration or by lowering the temperature. The interaction of DTX with Mg2+ was further analyzed at a low cation concentration, at which DTX reduced both IA and the delayed rectifier IK. These results were correlated with the action of DTX on the neuromuscular junction. Its facilitatory effect on excitatory junctional potentials (EJPs) was relatively mild but the effect was drastically enhanced when combined with certain mutations and K+ channel blocking drugs, leading to repetitive or prolonged giant EJPs. Only the mutations or drugs that reduced IK or the Ca2(+)-dependent K+ current, ICF, could yield these synergistic effects with DTX. In contrast, the abnormal EJPs caused by the mutation or drug that blocked IA were not further enhanced by DTX, indicating that DTX also affects IA at the neuromuscular junction. Thus, the A-type K+ channels in muscle and nerve terminals appeared very similar in their sensitivity to the specific toxin, drugs and mutations examined here.

[Evaluation of coronary artery fistula using a color Doppler flow imaging technique]

Two unusual cases with coronary artery fistula were reported. The diagnoses were first made by color Doppler flow imaging and confirmed by selective coronary angiography and operation. In the first case, color Doppler revealed a continuous flow signal within the dilated left coronary artery and a turbulent jet within the right atrium. In the second case, color Doppler showed turbulent flow signals which could be traced from the proximal left coronary artery, along the left ventricular posterior wall and into the left ventricle. The high velocities at the site of drainage of fistula were recorded by the continuous-wave Doppler and the calculated pressure gradient confirmed that the abnormal flow was from the systemic circulation. We are of the opinion that color Doppler flow imaging is a reliable technique for detecting coronary artery fistula and the combination of color Doppler with continuous-wave Doppler is essential for evaluating the hemodynamics of the shunt flow.