Shingle-back lizards crush snail shells using temporal summation (tetanus) to increase the force of the adductor muscles

Summary During the crushing of hard objects, the adductor muscles ofTrachydosaurus are activated in an unfused tetanus with the tetanic pulses of the several motor units occurring in synchrony.     

麦芽根中5′-磷酸二酯酶的制备及性质

从麦芽根中提取5′－磷酸二酯酶，酶活可达474U／mL。将所得酶液用于水解酵母核糖核酸，得到5′－CMP、UMP、GMP、AMP4种单核苷酸。最佳反应条件为：底物RNA浓度为0.01g/mL，每毫升底物的酶用量为30U，酶解温度70℃，pH7.0，时间2h,5′－核苷酸转化率达80％。     

计量抽样检查中“μ”法的设计

在计量抽样检查的国际标准ISO3951和国家标准(送审稿)中,都没有给出总体质量特征X～N(μ,σ~2),均值μ已知,标准差σ未知情形的抽样检查方案。本文提出了这种抽样方案的设计方法。称之为μ-法抽样检查。首先,在给定了两类错误的概率α,β时,求出了具有单侧上规格限情形的接收准则,OC函数,标准方程。然后利用迭代法求出样本数n,再得到抽样检查方案(n,h~2)。同时,还对具有单侧下规格限、分立双侧规格限情形,讨论了抽样方案的制订以及它们的图解法。最后,讨论了综合双侧规格限情形的接收准则及图解法。     

Molecular forms of dopamine beta-hydroxylase in rat superior cervical ganglion and adrenal gland

Summary Dopamine beta-hydroxylase (DBH) enzyme activity was associated in rat superior cervical ganglion with tetrameric DBH-A (294,000 D) and dimeric DBH-B (147,000 D) and in rat adrenal gland with DBH-A and a novel molecular form of DBH, defined as DBH-C, with a molecular weight of 125,000 D. Pretreatment of the rats with cycloheximide markedly reduced DBH activity without altering the molecular heterogeneity.     

Retinol: Predominant form of vitamin A in corpus luteum

Summary We could not confirm the results of a previous research group^2,3 which stated that retinal (vitamin A aldehyde) is present in corpus luteum of bovine origin. On the contrary we establish the occurrence of retinol (vitamin A alcohol) in both human and bovine corpora lutea. Identity of the compound is confirmed by its chromatographic behavior on high performance liquid chromatographic systems (adsorption and reversed phase) and by spectrometric analysis (UV, fluorimetry).Acknowledgments. The authors are indebted to Prof. D. Vandekerckhove and Prof. F. Derom, University of Gent, Faculty of Medecine, for supplying human corpora lutea.     

Immunological profile of breast cancer patients in early or advanced disease

Summary Immune reactivity of patients with early or advanced breast cancer, compared with healthy controls, has been measured using in vivo and in vitro tests. The results of our study show that impairment of cellular responsiveness occurred in women with advanced disease.This work was supported in part by the CNR, Italy-USA Contract No. 7801062.65, and in part by the Region of Umbria, Italy. Acknowledgment. We wish to thank Mr Mario Andrielli for his expert technical assistance.