On a Model for Hazard Rates

This note proposes a new model for summarising data on survival distribution. A simple graphical method (or equivalently a linear-regression-based method) for estimation of parameters is given. The model is shown to describe adequately data on Survivorship of Starling Birds reported by LACK (1943) and data on power generators reported by DHILLON (1981). A comment is added to illustrate how one can obtain a goodness of fit statistic which has a chi-squared distributions.     

Rapid,high-yield purification of rat liver 3-hydroxy-3-methyl-glutaryl-coenzyme a reductase

A rapid method for the purification of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase from the livers of cholestyramine-fed rats is reported. The procedure involves a sequence of separations on affinity chromatography columns consisting of Blue Dextran-Sepharose, agarose-CoA, and agarose-HMG-CoA. The advantage of this method is its flexibility in scavenging enzyme that might be lost during purification, resulting in a yield of homogeneous reductase (specific activity approximately 10,000 nmol/min/mg protein) as high as 50%, which is at least twice that previously reported.     

细菌巨大质粒的快速检测

本文报道了一种快速检测微生物巨大质粒的方法．该方法是通过对Ｅｃｋｈａｒｄｔ所报道的方法加以改进,使之能对根瘤菌、大肠杆菌、甚至链霉菌的大质粒进行快速检测．     

Preparative isolation of the two forms of pig pancreatic pro-(carboxypeptidase A) and their monomeric carboxypeptidases A.

A method is reported for the preparative isolation of the two forms of pro-(carboxypeptidase A) from pig pancreas: the monomer and the binary complex with pro-(proteinase E). This method, which is mainly based on chromatography on DEAE-Sepharose at pH 5.7, allows these proenzymes to be prepared more quickly and in safer conditions than with other reported methods. Undegraded and homogeneous carboxypeptidase A1 and A2 species (peptidyl-L-amino acid hydrolase, EC 3.4.17.1), in monomeric forms with high specific activity, are also obtained in high yield by controlled trypsin activation of either of the pro-(carboxypeptidases A) followed by chromatography on DEAE-Sepharose at pH 5.8 under dissociating conditions (7 M-urea).     

Removal of Stainable Cytoplasmic Substances from Cytogenetic Slide Preparations

A method to remove stainable cytoplasmic substances from cytogenetic preparation using RNase A treatment is reported. The preparations processed with this method are especially useful for the automated analysis of mi-cronuclei of cultured cells with cytochalasin B and of chromosome aberrations induced by radiation.     

A fluorescence assay for enzymes that cleave glycosidic linkages to produce reducing sugars

A rapid, facile, and sensitive assay has been developed for enzymes that generate reducing sugars. The assay is a modification of a method for post-HPLC column derivatization and detection of reducing sugars and is carried out in a single test tube. The assay is useful for large numbers of samples, such as those produced during purification of enzymes. Less than 500 pmol of reducing sugar can be quantitatively measured. The assay reported here is at least 10 times more sensitive than either the commonly employed parahydroxybenzoic acid hydrazide method or the recently reported bicinchoninate method, and 50 times more sensitive than the Nelson-Somogyi method.     

Use of high-performance liquid chromatography for quantitative determination of the native form of the third component C3 of human complement

A high-performance liquid chromatography method is reported for the quantitative determination of the intact C3, the third component of complement, in solutions containing inactivated C3. This method is simple and far more sensitive than a conventional method using 5,5'-dithiobis(2-nitrobenzoic acid).     

三种致病疫霉交配型分子检测方法的比较

致病疫霉Phytophthora infestans属于异宗配合卵菌,当A1、A2两种交配型同时存在时,可以进行有性生殖,产生卵孢子。检测疫霉菌交配型的传统方法是采用对峙培养,这种方法耗时长并且需要标准的A1、A2交配型菌株作为参照。因此,人们希望开发出更加简便和快捷的可直接基于核苷酸序列差异的分子检测方法。目前,已报道了3个与致病疫霉交配型紧密连锁的分子标记可用于交配型的检测。本研究用64株致病疫霉菌比较了3种基于交配型分子标记的检测方法与传统方法检测的结果。结果显示,依据分子标记的3种分子检测方法与传统对峙培养方法测定的交配型结果一致率为61%-73%,而且3种分子检测方法都不能检测出自育菌株。因此,致病疫霉交配型的分子检测方法还有待进一步研究。     

Rapid genotype analysis of the matrix metalloproteinase-1 gene 1G/2G polymorphism that is associated with risk of cancer.

A bi-allelic polymorphism in the promoter of the human matrix metalloproteinase-1 gene has been reported. It has been found to have a functional effect on the promoter strength and to be associated with risk of cancers. The polymorphism is due to an insertion/deletion of a guanine, and conventional methodologies for genotyping this polymorphism are time-consuming and expensive. A rapid genotyping method based on restriction endonuclease digestion is reported here.     

Locally optimum run-length compression of CT images without restriction on the pixel value

Previously reported locally optimum run-length compression of CT images is only applicable to 12 bit images. In order to extend this method to images whose pixel values may vary from 8 bits per pixel to 16 bits per pixel, single byte coding is suggested. A search method is also suggested to make a reasonable determination of the length of non-compressible pixels. Experiments have shown that single byte coding is successful, giving compressed results which are comparable with previously reported results.     

大孔吸附树脂—紫外分光光度法测定肉苁蓉中苯乙醇甙类的含量

本文报道了肉苁蓉的乙醇提取物,经大孔吸附树脂富集、纯化苯乙醇甙类成分后,用紫外分光光度法测定其含量。该法操作简便,灵敏,结果准确。平均回收率96.13％,变异系数3.4％。     

Preparation of Inositol Triphosphate from Brain: GLC of Trimethylsilyl Derivative

A simple method for the preparation of myo-inositol triphosphate from brain is described that does not require the prior isolation of phosphatidylinositol diphosphate (triphosphoinositide). A gas chromatographic procedure for detection of inositol triphosphate is reported.     

A new process for the treatment of fertilizer effluent using immobilized urease

A method is reported for the treatment of industrial fertilizer effluent rich in urea by a new coupling method to immobilize crude urease onto polyester which is having high flow through property in columns. Kinetics of the immobilized enzyme is established in small column. A typical treatment process with two larger columns in packed bed mode is discussed with and without recycling the treated effluent.     

A method for the quantitative determination of hypoglycin A in the presence of leucine.

A spectrophotometric method for the quantitative determination of the toxic amino acid hypoglycin A in mixtures with leucine is reported. Hypoglycin A is the hypoglycemic principle found in the arilli of the fruit of Blighia sapida (ackee).     

The purification of potato lectin by affinity chromatography on an N,N',N'-triacetylchitotriose-Sepharose matrix.

A new, rapid method is described for purification of potato lectin using an N,N′,N″-triacetylchitotriose-Sepharosematrix. The method is less time consuming than the previously reported purification procedures.     

A new continuous optical assay for maltase and sucrase.

A new method for the assay of maltase and sucrase is reported. The method makes use of mutarotase, hexokinase and glucose 6-phosphate dehydrogenase as ancillary enzymes. The reaction is linear at least up to a delta E/min of 0.13.     

Synthetic peptides including acidic clusters as substrates of yeast casein kinase-2

The synthesis is reported of a series of glutamyl peptide analogs of the model substrate H-Ser-Glu-Glu-Glu-Glu-Glu-OH of casein kinase-2 (CK-2). A convenient HPLC method for the separation of slightly different acidic peptides is also reported. The site specificity of yeast casein kinase-2 (Y-CK2) is examined with the aid of synthesized peptide substrates.     

A new method of measurement of permeability of lipid membranes

A new method, based on potential measurements to obtain permeabilities and mobilities of ionic species passing through membranes, under the influence of concentration gradients is proposed. This method is applied to three different lipid membranes in aqueous KCl solutions. The values of permeabilities and mobilities obtained by this simple method is in good agreement with those reported in literature     

Efficient method for the synthesis of an important precursor of constrained peptides

A practical method for the synthesis of an important precursor of constrained peptides involving only three steps from commercial inexpensive precursors is reported.     

A silver impregnation method for embedded central nervous tissue of the rat

A simple and yet reliable silver impregnation method, using potassium ferrocyanide, for demonstrating nervous tissue of the rat central nervous system embedded in paraffin or paraplast is described. The method reported here is compared and discussed with earlier techniques using potassium dicyanoargentate, potassium ferrocyanide and potassium ferricyanide.