Models of Independent Action for Combination Therapy

Two methods of applying Finney's concept of simple independent action are suggested for examining possible synergism in combination therapy. In one model the treatments act independently at one time to cure the disease. In the other model the treatments act independently continuously to prevent the disease from progressing to a terminal outcome. The implications of these models for the interaction terms of a proportional hazards model, a log-linear model on death rates, and a logistic model are discussed.     

裂裂区设计在肥料试验中的应用

裂裂区设计（亦称再裂区设计）是裂区原理的扩展，把副区分成副副区，并指定为第三个处理因子，试验结果表明，这种设计可以更精确地鉴定副副区的因子效应和包括这个因子在内的交互作用．一次试验可以同时鉴定出10种效应的平均数．     

Effects of silver on ethylene synthesis and action in cut carnations

Silver, applied as silverthiosulphate, completely blocked the ethylene surge preceding the wilting of the petals. As a consequence, vase life was extended by nearly 100%. In addition, a pretreatment with silverthiosulphate caused the flowers to become insensitive to an ethylene treatment.     

A novel labeling procedure of anteiso-fatty acid-containing lipids in staphylococci for investigating the effect of penicillin on lipid release

L-[4,5-3H]isoleucine was introduced to label anteiso-fatty acid (AIFA)-containing lipids in Staphylococcus aureus SG 511. After an overnight incubation in peptone broth in the presence of 37 kBq L-[4,5-3H]isoleucine/ml, 8.5-13% of the total radioactivity applied was found to be incorporated into the cells. 22.4-25.6% of the incorporated radioactivity was found in AIFA-containing lipids extracted by chloroform-methanol-water (2:1:0.2, v/v/v) at pH 2. The interphase contained 70-75% of the incorporated radioactivity. Lipoteichoic acid, extracted by phenol-water (80:20, w/v) contained less than 1% of the incorporated radioactivity, as measured after purification by hydrophobic interaction chromatography on octyl sepharose gel. Within 1 h after addition of 10 micrograms/ml penicillin G to exponentially growing cultures of S. aureus, that led to non-lytic death of the cells, 11.9-18.1% of the incorporated L-[4,5-3H]isoleucine label were released. Lipids containing AIFA were excreted to 5.4-8.4% of total incorporated activity; this amount represents more than 1/4 of the labeled cellular lipids.     

Ca−K Bi-ionic action potential in squid giant axons

Summary Under intracellular perfusion with a solution containing K⁺ as the sole cation species, squid giant axons were found to be capable of developing all-or-none action potentials when immersed in a medium in which CaCl₂ was the only electrolyte. The adequate range of ion concentration for demonstrating this capability was mentioned. The reversal potential level measured by the voltage-clamp technique varied directly with the logarithm of the concentration of extracellular Ca-ion; the proportionality constant was close toRT/2F. The action potential observed under this Ca–K bi-ionic condition could not be suppressed by addition of tetrodotoxin or saxitoxin to the external medium. The external Ca-ion could be replaced with Co- or Mn-ion without eliminating the capability of the axons to develop action potentials. D-600 could not suppress the inward current observed under the voltage-clamp condition, but 4-aminopyridine could suppress it. The experimental findings were interpreted based on the current channel hypothesis and on the macromolecular theory.     

AT-Hook Transcription Factors Restrict Petiole Growth by Antagonizing PIFs

1. Download : Download high-res image (158KB)
2. Download : Download full-size image

     

Hypocalcemia-Induced Seizure: Demystifying the Calcium Paradox

Calcium is essential for both neurotransmitter release and muscle contraction. Given these important physiological processes, it seems reasonable to assume that hypocalcemia may lead to reduced neuromuscular excitability. Counterintuitively, however, clinical observation has frequently documented hypocalcemia’s role in induction of seizures and general excitability processes such as tetany, Chvostek’s sign, and bronchospasm. The mechanism of this calcium paradox remains elusive, and very few pathophysiological studies have addressed this conundrum. Nevertheless, several studies primarily addressing other biophysical issues have provided some clues. In this review, we analyze the data of these studies and propose an integrative model to explain this hypocalcemic paradox.     

Seedling development in buckwheat and the discovery of the photomorphogenic shade‐avoidance response

Numerous botanists of the early 19th century investigated the effect of sunlight on plant development, but no clear picture developed. One hundred and fifty years ago, Julius Sachs (1863) systematically analysed the light–plant relationships, using developing garden nasturtium (Tropaeolum majus) and seedlings of buckwheat (Fagopyron esculentum) as experimental material. From these studies, Sachs elucidated the phenomenon of photomorphogenesis (plant development under the influence of daylight) and the associated ‘shade‐avoidance response’. We have reproduced the classical buckwheat experiments of Sachs (1863) and document the original shade‐avoidance syndrome with reference to hypocotyl elongation and cotyledon development in darkness (skotomorphogenesis), white light and shade induced by a canopy of green leaves. In subsequent publications, Sachs elaborated his concepts of 1863 and postulated the occurrence of ‘flower‐inducing substances’. In addition, he argued that the shade‐avoidance response in cereals, such as wheat and maize, is responsible for lodging in crowded plant communities. We discuss these processes with respect to the red‐ to far‐red light/phytochrome B relationships. Finally, we summarise the phytochrome B–phytohormone (auxin, brassinosteroids) connection within the cells of shaded Arabidopsis plants, and present a simple model to illustrate the shade‐avoidance syndrome. In addition, we address the relationship between plant density and health of the corresponding population, a topic that was raised for the first time by Sachs (1863) in his seminal paper and elaborated in his textbooks.     

COPD symptoms in the morning: impact,evaluation and management

Chronic obstructive pulmonary disease (COPD) symptoms in the morning, including dyspnea and sputum production, affect patients’ quality of life and limit their ability to carry out even simple morning activities. It is now emerging that these symptoms are associated with increased risk of exacerbations and work absenteeism, suggesting that they have a more profound impact on patients than previously thought. The development of validated patient-reported outcome (PRO) questionnaires to capture patients’ experience of COPD symptoms in the morning is, therefore, vital for establishing effective and comprehensive management strategies. Although it is well established that long-acting bronchodilators are effective in improving COPD symptoms, the limited available data on their impact on morning symptoms and activities have been obtained with non-validated PRO questionnaires. In this review, we discuss the impact of COPD symptoms in the morning and available tools used to evaluate them, and highlight specific gaps that need to be addressed to develop standardized instruments able to meet regulatory requirement. We also present available evidence on the effect of pharmacological therapies on morning symptoms.     

SRA的RNA和蛋白质均有转录辅激活功能

类固醇受体激活物（steroid receptor activator, SRA）是一种 类固醇受体辅激活物.最初的研究认为,SRA只存在RNA形式,不存在蛋白质 形式.但是后来的研究发现,SRA是在RNA和蛋白质两个水平上发挥功能的分 子,其cDNA序列存在687 bp保守的核心区域,该核心区域对其发挥转录共激 活活性是必需的.SRA的RNA形式主要参与核受体的转录共激活作用,其表达 与乳腺癌的发生有很大关系,SRA的蛋白质形式（steroid receptor activator protein ,SRAP）也具有类似的功能.但是不同于RNA形式, SRAP可结合到特定基因的启动子区域,并起到阻遏物的作用.本文对SRA的 特点、表达及功能等方面的最新研究进展及其可能的作用机制与作用形式 进行概述.