Characterization of mutated transforming growth factor-beta s which possess unique biological properties

Transforming growth factor-beta (TGF-beta) is a potent regulator of cell growth and differentiation. On the basis of the crystal structure of TGF-beta 2, we have designed and synthesized two mutant TGF-beta s, TGF-beta 1 (71 Trp) and TGF-beta 1 (delta 69-73). Although both of these molecules inhibited the growth of Mv1Lu mink lung epithelial cells and LS1034 colorectal cancer cells, which are affected equally by TGF-beta 1 and TGF-beta 2, TGF-beta 1 (delta 69-73) was much less potent than TGF-beta 1 or TGF-beta 1 (71 Trp) at inhibiting the growth of LS513 colorectal cancer cells which are growth-inhibited by TGF-beta 1 but not TGF-beta 2. Both TGF-beta 1 (71 Trp) and TGF-beta 1 (delta 69-73) increased levels of mRNAs for fibronectin and plasminogen activator inhibitor with Mv1Lu cells, whereas only TGF-beta 1 (71 Trp) and not TGF-beta 1 (delta 69-73) up-regulated the mRNA level of carcinoembryonic antigen in LS513 cells. The expression level of carcinoembryonic antigen mRNA in LS1034 cells was not altered by either wild-type or mutant TGF-beta s. Receptor labeling experiments demonstrated that TGF-beta 1 (71 Trp) bound with high affinity to the cell-surface receptors of Mv1Lu, LS1034, and LS513 cells while TGF-beta 1 (delta 69-73) bound effectively to the receptors of Mv1Lu and LS1034 cells but much less to the receptors on LS513 cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

PVC敏感膜组分比对K~＋─ISFET响应特性的影响

本文研究了以二苯并—３０—冠—１０作为敏感物质的ＰＶＣ膜Ｋ~＋—ＩＳＦＥＴ传感器，以及改变膜中的敏感物质和增塑剂的组分比对Ｋ~＋—ＩＳＦＥＴ响应特性的影响．同时，对Ｋ~＋敏感膜的响应机理进行了讨论。实验结果与理论分析相符。     

LF6铝合金的超塑性／扩散连接组合工艺试验及理论研究EI

本文研究了ＬＦ６铝合金的超塑性／扩散连接组合工艺，用变形和再结晶的方法细化晶粒，成功地进行了ＳＰＦ／ＤＢ工艺试验，利用电子探针观察了扩散连接接头的界面微观区域，并从机理上分析了金属的超塑性／扩散连接两种工艺之间的内部联系及其金属学行为。     

Differential response of arteries and vein grafts to blood flow reduction

BACKGROUND: Because the relative efficacy of antiarrhythmic agents on halothane-epinephrine arrhythmias has not been well characterized, this study was undertaken to comparatively evaluate the antiarrhythmic action of Na(+)-, K(+)- and Ca(2+)-channel blockers on epinephrine-induced ventricular arrhythmias during halothane anesthesia in rats. METHODS: Rats were anesthetized at random with either halothane (1.5%), isoflurane (2.0%), or pentobarbital (50 mg/kg intraperitoneally), and the lungs were mechanically ventilated with oxygen. The rats were studied in three consecutive protocols. Protocol I determined the arrhythmogenic thresholds of epinephrine during the three types of anesthesia in 33 rats. Protocol II determined the arrhythmogenic thresholds of epinephrine during halothane anesthesia in 64 rats receiving saline (control) or one of five antiarrhythmic agents. Protocol III measured the duration of epinephrine-induced arrhythmias during halothane anesthesia in 42 rats receiving saline (control) or one of five antiarrhythmic agents. RESULTS: In protocol I, the arrhythmogenic doses of epinephrine during halothane, isoflurane, or pentobarbital anesthesia were 1.7 +/- 3.2, 11.1 +/- 0.6, and 39.0 +/- 3.9 micrograms/kg, respectively, and the corresponding plasma concentrations were 4.3 +/- 0.8, 103.7 +/- 9.2, and 246.7 +/- 28.9 ng/ml, respectively. In protocol II, the arrhythmogenic doses were similar in rats receiving saline and in those receiving lidocaine. The arrhythmogenic doses in rats receiving verapamil, flecainide (Na(+)- and K(+)-channel blocker), E-4031 (K(+)-channel blocker), or amiodarone(K(+)-channel blocker with Na(+)-, Ca(2+)-, and beta-blocking activity) increased significantly, i.e., 4.2, 4.2, 5.5, and 31.7 times control (P < 0.01). In protocol III, lidocaine had no effect on the duration of arrhythmias. Flecainide, E-4031, and verapamil markedly reduced the duration of arrhythmias induced by epinephrine, 8 micrograms/kg intravenously (P < 0.01), whereas only amiodarone markedly reduced the duration of arrhythmias induced by epinephrine, 16 micrograms/kg intravenously (P < 0.01). CONCLUSIONS: It was concluded that agents with K(+)-channel blocking properties were the most effective in preventing halothane-epinephrine arrhythmias in rats.     

Reduction of triceps muscle force after shortening of the distal humerus: a computational model

A retrospective case reference study examining the use of alcohol and tobacco in 303 women aged 40 or over suffering from oral or oropharyngeal cancer was conducted in the south-west Netherlands. Both alcohol and tobacco consumption are important in the development of oral and oropharyngeal cancer with increased consumption of both markedly increasing the risks of cancer, but alcohol having the greater effect.