Ecdysteroids in adults of the nematode, Dirofilaria immitis

Adult males and females of the dog heartworm, Dirofilaria immitis, were extracted separately and, following separation of the free and conjugated ecdysteroid fractions, the conjugates were hydrolysed enzymically. Both the ecdysteroids released by hydrolysis of the conjugates and the free hormones were further purified and analysed by a combination of radioimmunoassay, thin-layer chromatography and high-performance liquid chromatography monitoring fractions by radioimmunoassay, and by gas-liquid chromatography/mass spectrometry (selected ion monitoring). Both males and females contained free and conjugated ecdysteroids. Evidence was obtained for the presence of ecdysone, 20-hydroxyecdysone, 20,26-dihydroxyecdysone and possibly ponasterone A. The possible parallel between ecdysteroid endocrinology in nematodes and insects is discussed.     

Gas chromatography analysis of serum cholesterol synthesis and absorption markers used to predict the efficacy of simvastatin in patients with coronary heart disease

Objectives

We investigated the changes in cholesterol absorption and synthesis markers before and after simvastatin therapy in Chinese patients with coronary heart disease.

Design and method

We developed a gas chromatography method to identify cholesterol synthesis and absorption markers and measured them in patients with coronary heart disease. We then tested their use in predicting the efficacy of simvastatin in lowering cholesterol. Serum samples from 45 patients and 38 healthy humans (controls) were analyzed in a gas chromatography–flame ionization detector.

Results

Squalene and five non-cholesterol sterols—desmosterol and lathosterol (synthesis markers) and campesterol, stigmasterol, and sitosterol (absorption markers)—were detected. The recovery rates of the markers were 95–102%. After simvastatin treatment for four weeks, the total cholesterol and low-density lipoprotein cholesterol levels had significantly decreased from the baseline values (p < 0.05). The baseline lathosterol level was significantly higher in good responders than in poor responders (p < 0.05), and the stigmasterol level was significantly lower in good responders than in poor responders (p < 0.05).

Conclusions

This method should be suitable for the detection of serum squalene and non-cholesterol markers and can be used to predict the efficacy of simvastatin in patients with coronary heart disease.     

头孢吡肟中间体合成条件考察

目的：在现有的实验室务件下以7-ACA为原料合成头孢吡肟中间体，并在一定程度上提高收率。方法：与国外文献报道的相关方法具有一致性，同时，采用正交实验设计方法考察了一些关键步骤(时间、温度、剂量)对中间体收率的影响。结果：中间体收率为32．7％。结论：该方法使中间体的合成更易于控制，避免了一些繁杂的操作，并降低了实验成本。