Fractionation of outdated freeze-dried plasma: a comparative study of cold- and heat-ethanol fractionation procedures.

In a comparative study a total volume of 1435 kg outdated freeze-dried plasma, equivalent to approx. 200,000 kg liquid plasma, was fractionated into albumin (20%): about 30% of the total plasma volume was fractionated following the cold-ethanol procedure and about 70% following the heat-ethanol method. Average albumin recovery following cold-ethanol preparation was 47% of the albumin originally present in the freeze-dried plasma (= 50% of total protein); following heat-ethanol fractionation, 71%. Gelfiltration of heat-ethanol albumin showed a main peak (= 93%) representing albumin monomers and one slightly faster component (= 7%) representing albumin dimers. Gelfiltration of cold-ethanol isolated albumin on the other hand showed four peaks: albumin monomers (= 60%), albumin dimers (= 15%), and two other peaks representing higher molecular weight molecules (= 25%). Hemoglobin present in the reconstituted plasma was reduced about five-fold in the cold-ethanol product and about ten-fold in the heat-ethanol albumin. Stability tests of both products did not differ from equivalent products isolated from normal human plasma. Besides albumin, immunoglobulins may be isolated as Cohn fraction II-III prior to the heating procedure without significant albumin loss.     

The use of β-propiolactone for the sterilization of heat-labile materials

A short literature survey on chemical sterilization with -propiolactone is given. The auto-inactivatio 1 of this compound in aqueous solution appears to be one of its main advantages.Time-kill studies have been carried out with bacterial cells and spores, and with fungal spores. The compatibility of BPL with textiles and plastics was also studied to some extent. It is concluded that heat-sensitive materials can be sterilized with a 1.0% aqueous solution of BPL within one hour at room temperature. The compatibility of BPL with the materials studied does not appear to offer serious problems.     

"Schizophrenic" Hemocompatible Copolymers via Switchable Thermoresponsive Transition of Nonionic/Zwitterionic Block Self-Assembly in Human Blood

"Schizophrenic" diblock copolymers containing nonionic and zwitterionic blocks were prepared with well-controlled molecular weights via atom-transfer radical polymerization (ATRP). In this work, we report a systematic study of how morphological changes of poly(N-isopropylacrylamide)-block-poly(sulfobetaine methacrylate) (PNIPAAm-b-PSBMA) copolymers affect hemocompatibility in human blood solution. The "schizophrenic" behavior of PNIPAAm-b-PSBMA was observed by (1)H NMR, dynamic light scattering (DLS), and turbidity measurement with double morphological transition, exhibiting both lower critical solution temperature (LCST) and upper critical solution temperature (UCST) in aqueous solution. Below the UCST of PSBMA block, micelles were obtained with a core of insoluble PSBMA association and a shell of soluble PNIPAAm, whereas the opposite micelle structure was observed above the LCST of PNIPAAm block. In between the UCST and LCST, unimers with both soluble blocks were detected. Hydrodynamic size of prepared polymers and copolymers is determined to illustrate the correlations between intermolecular nonionic/zwitterionic associations and blood compatibility of PNIPAAm, PNIPAAm-b-PSBMA, and PSBMA suspension in human blood. Human fibrinogen adsorption onto the PNIPAAm-b-PSBMA copolymers from single-protein solutions was measured by DLS to determine the nonfouling stability of copolymer suspension. The new nonfouling nature of PNIPAAm-b-PSBMA copolymers was demonstrated to show extremely high anticoagulant activity and antihemolytic activity in human blood over a wide range of explored temperatures from 4 to 40 °C. The temperature-independent blood compatibility of nonionic/zwitterionic block copolymer along with their schizophrenic phase behavior in aqueous solution suggests their potential in blood-contacting applications.     

分支分类学中和谐性概念与和谐性分析方法

和谐性是分支分类学中的一个基本概念。本文给出一个和谐性的数学定义,称为Kexue和谐性。并在Kexue和谐性的基础上开发出一个新的和谐性分析方法。并对该方法在分支分类研究中的应用进行讨论。     

An innovative SNP genotyping method adapting to multiple platforms and throughputs

Key message

An innovative genotyping method designated as semi-thermal asymmetric reverse PCR (STARP) was developed for genotyping individual SNPs with improved accuracy, flexible throughputs, low operational costs, and high platform compatibility.

Abstract

Multiplex chip-based technology for genome-scale genotyping of single nucleotide polymorphisms (SNPs) has made great progress in the past two decades. However, PCR-based genotyping of individual SNPs still remains problematic in accuracy, throughput, simplicity, and/or operational costs as well as the compatibility with multiple platforms. Here, we report a novel SNP genotyping method designated semi-thermal asymmetric reverse PCR (STARP). In this method, genotyping assay was performed under unique PCR conditions using two universal priming element-adjustable primers (PEA-primers) and one group of three locus-specific primers: two asymmetrically modified allele-specific primers (AMAS-primers) and their common reverse primer. The two AMAS-primers each were substituted one base in different positions at their 3′ regions to significantly increase the amplification specificity of the two alleles and tailed at 5′ ends to provide priming sites for PEA-primers. The two PEA-primers were developed for common use in all genotyping assays to stringently target the PCR fragments generated by the two AMAS-primers with similar PCR efficiencies and for flexible detection using either gel-free fluorescence signals or gel-based size separation. The state-of-the-art primer design and unique PCR conditions endowed STARP with all the major advantages of high accuracy, flexible throughputs, simple assay design, low operational costs, and platform compatibility. In addition to SNPs, STARP can also be employed in genotyping of indels (insertion–deletion polymorphisms). As vast variations in DNA sequences are being unearthed by many genome sequencing projects and genotyping by sequencing, STARP will have wide applications across all biological organisms in agriculture, medicine, and forensics.

     

An Improved Technique for Dissociating Hepatocytes from Fixed Mouse Liver for Cytochemistry

A refined version of a method described previously for dissociating hepatocytes from fixed liver is described. The objective was to develop a procedure that would dispense with the postosmication of previously fixed tissue. In the new procedure fixed liver blocks are wrapped with a quadruple layer of nylon cloth, and, by squeezing them in a buffer solution, individually dissociated cells pass through the cloth without significant damage. The procedure makes it possible to dissociate liver tissue fixed with modified Karnovsky's fixative, Zamboni's fixative or cacodylate buffered glutaraldehyde. The subsequent compatibility of the single cells obtained with many cytochemical procedures has been confirmed.     

An improved technique for dissociating hepatocytes from fixed mouse liver for cytochemistry

A refined version of a method described previously for dissociating hepatocytes from fixed liver is described. The objective was to develop a procedure that would dispense with the postosmication of previously fixed tissue. In the new procedure fixed liver blocks are wrapped with a quadruple layer of nylon cloth, and, by squeezing them in a buffer solution, individually dissociated cells pass through the cloth without significant damage. The procedure makes it possible to dissociate liver tissue fixed with modified Karnovsky's fixative, Zamboni's fixative or cacodylate buffered glutaraldehyde. The subsequent compatibility of the single cells obtained with many cytochemical procedures has been confirmed.     

Interferometric investigation of near-membrane diffusion layers

This paper presents an interferometric method of the investigation of near-membrane diffusion layers. With the aid of this method a concrete investigation was made of such layers formed in the neighbourhood of a horizontally situated membrane which separates solutions of different concentrations. On the basis of interferograms obtained, a computer analysis of these interferograms is made. This permitted to obtain, among others, curves of the distribution of solution concentrations within these layers. These curves are next compared with curves made on the basis of equations given in the paper [16]. A satisfactory compatibility between the results of the experimental and theoretical investigations are obtained.     

ARE SPECIES REAL? THE SHAPE OF THE SPECIES BOUNDARY WITH EXPONENTIAL FAILURE,REINFORCEMENT, AND THE “MISSING SNOWBALL”

Under simple assumptions, the evolution of epistatic "Dobzhansky–Muller" incompatibilities between a pair of species should yield an accelerating decline of log overall reproductive compatibility—a "snowball" effect that might rapidly provide new species with "reality." Possible alternatives include: (1) simple exponential failure, giving a linear rate of log compatibility loss, and (2) "slowdown," likely during reinforcement in which mate choice evolves to prevent deleterious hybridization, yielding a decelerating log compatibility loss. In analyses of multiple datasets, we find little support for the snowball effect, except possibly in Lepidoptera hybrid viability. The snowball predicts a slow initial rate of incompatibility acquisition, with low initial variance; instead, highly variable compatibility is almost universally observed at low genetic distances. Another deviation from predictions is that reproductive isolation usually remains incomplete until long after speciation. These results do not disprove snowball compatibility decay, but can result if large deleterious effects are due to relatively few genetic changes, or if different types of incompatibility evolve at very different rates. On the other hand, data on Bacillus and Saccharomyces , as well as theories of chromosomal evolution, suggest that some kinds of incompatibility accumulate approximately linearly, without Dobzhansky–Muller effects. In microorganisms, linearity can result from direct negative effects of DNA sequence divergence on compatibility. Finally, a decelerating slowdown model is supported for sympatric Leptasterias starfish, and in Drosophila prezygotic isolation in sympatry but not allopatry, providing novel comparative evidence for reinforcement.     

Stability of 5-Fluoro-2′-deoxycytidine and Tetrahydrouridine in Combination

In vivo, the DNA methyltransferase inhibitor, 5-fluoro-2′-deoxycytidine (FdCyd, NSC-48006), is rapidly converted to its unwanted metabolites. Tetrahydrouridine (THU, NSC-112907), a cytidine deaminase inhibitor can block the first metabolic step in FdCyd catabolism. Clinical studies have shown that co-administration with THU can inhibit the metabolism of FdCyd. The National Cancer Institute is particularly interested in a 1:5 FdCyd/THU formulation. The purpose of this study was to investigate the in vitro pH stability of FdCyd and THU individually and in combination. A stability-indicating high-performance liquid chromatography method for the quantification of both compounds and their degradants was developed using a ZIC®-HILIC column. The effect of THU and FdCyd on the in vitro degradation of each other was studied as a function of pH from 1.0 to 7.4 in aqueous solutions at 37°C. The degradation of FdCyd appears to be first-order and acid-catalyzed. THU equilibrates with at least one of its degradants. The combination of FdCyd and THU in solution does not affect the stability of either compound. The stability and compatibility of FdCyd and THU in the solid state at increased relative humidity and at various temperatures are also evaluated.     

Phenotypic characterization of fi- R factors determining the restriction and modification hsp II specificity

Summary All known determinants of the restriction, modification specificity hsp II are plasmids of the compatibility class N. Two I-like R factors, R56 and R64 are able to interfere with the lytic cycle of phage (in liberation of phage by lysogens or newly infected cells) by a different mechanism.     

Determinants of Compatibility in Mollusc-Trematode Parasitism

The low prevalence of schistosome-infected snails in hyperendemichabitats, and the demonstrated ability of snails, in general,to recognize and eliminate a myriad of foreign substances and/orinfectious agents, lead to the postulate that host resistanceto larval trematodes must be considered the "rule," while susceptibility(compatibility) represents an exceptional occurrence. In thisreview, we discuss a variety of possible mechanisms by whichcompatibility between trematodes and their molluscan host mightbe attained. Included among these are parasite mimicry of snailhost molecules, prevention of opsonization, interference withhemocyte behavior or differential stimulation of hemocyte metabolicprocesses. Evidence that compatibility is the result of theability of larvae to resist toxic host molecules or to acquireprotective host components on their surface membranes is lacking.Clearly, there are multiple variables of both host and parasiteorigin which ultimately determine compatibility. Careful identificationand dissection of these variables will be required before weachieve a complete understanding of how compatible snail-trematodeassociations are established and maintained.     

Chemistry of alpha-hydroxymethylserine: problems and solutions

Further improvements related to the synthesis of peptides containing HmS are presented. Efficient synthetic protocols have been developed to synthesize "difficult" sequences containing a C-terminal HmS residue, MeA-HmS or consecutive HmS. Preparative methods for orthogonal N- and/or C-protected HmS(Ipr) derivatives are described. Their compatibility with standard solution or solid-phase peptide chemistry protocols allows synthetic flexibility toward HmS-containing peptides. In the synthesis of the sterically hindered dipeptides with the C-terminal HmS(Ipr) residue, HATU proves the highest efficiency, as compared with the fluoride and PyBroP/DMAP coupling methods. The HATU method also outperforms the fluoride activation in the solid-phase assembly of HmS homosequence. Specific protocols are described to overcome an undesired cyclization to diketopiperazines that occurs during the removal of Fmoc from dipeptides with the C-terminal HmS(Ipr) or HmS residues, thus precluding their C-->N elongation. The successful protocols involve: (i) the 2+1 condensation using mixed anhydride activation yielding the desired product with the highest optical integrity or (ii) use of the 2-chlorotrityl resin as a solid support sterically suppressing the undesired cleavage due to diketopiperazine formation. The latter approach allows the mild conditions of peptide cleavage from solid support, preserving the isopropylidene protection and minimizing the undesired N-->O-acyl migration that was observed under prolonged acid treatment used for cleaving the HmS peptide from the Wang resin.     

Several novel methods for immobilization of enzymes, microbial cells and organelles

Two novel methods--"photo-crosslinkable resin prepolymer method" and "urethane prepolymer method"--have been developed in our laboratory. These methods have the following advantages : 1) Prepolymers of desired properties, such as optional chain length, hydrophilicity or hydrophobicity, and ionic character etc., can be used for entrapment of biocatalysts : (2) preparation of gel-entrapped biocatalysts can be easily achieved under very mild conditions. Photo-crosslinked gels are conveniently obtained by several minutes illumination with near-UV light, of a mixture of liquid prepolymers having photo-sensitive functional groups, an appropriate sensitizer and the solution or suspension of biocatalyst. Formation of polyurethane gels is completed by only mixing water-miscible urethane prepolymers with the aqueous solution or suspension of biocatalyst. The biocatalysts entrapped by these methods are useful for a variety of purposes.     

Foam separation of DNA and proteins from solutions

Foam separation on BSA-DNA (bovine serum albumine/deoxyribonucleic acid) and Lysozyme-DNA systems is performed. The separation of the total protein from DNA is evaluated for dissociated chromatin solution. Foam separation for the same systems is done also by a new method of creating a pressure gradient in the Plateau-Gibbs borders in the foam and obtaining a "dry" foam. It is shown that the effectiveness of the foam separation can be improved significantly by the application of the latter method. Some factors (pH, initial concentration of the solution, expansion factor of the foam) influencing the separation of proteins from DNA in the foam and in the residual solution are studied as well.     

On a model of human bioenergetics

A three component hydraulic model has been proposed to represent the energy flows during human exercise and recovery. This model was accompanied by a sketch indicative of the graphical solution but had not been solved mathematically. This paper describes the model and demonstrates the method of mathematical solution, illustrated with a numerical example. Plotted graphically, this particular solution differs from both the "sketch solution" and from what actually happens under experimental conditions. These points of discrepancy are discussed with a view to their rectification and the development of a refined model.     

Solute—Water interactions: Do polyhydroxy compounds alter the properties of water?

The interactions between PHCs and water, like those between water molecules, are governed by hydrogen bonding. The details of these interactions are very sensitive to spacings and orientations of the OH groups on the solute molecules. Where different conformers can coexist in solution, the aqueous solvent acts so as to favor the conformer with the largest number of equatorial OH groups, because of their spatial compatibility with water.Because of this compatibility, aqueous solutions of PHCs have the tendency to supersaturation and incomplete freezing, manifestations of the phenomenon known as bound water which is, however, a misnomer. The range of water structure perturbation is probably governed by hydration forces which appear to dominate at solute-solute distances of < 3 nm and which decay exponentially. Although on a single hydrogen bond basis the hydration effects are marginal, they nevertheless are responsible for many macroscopic phenomena, e.g., gel formation, liquid crystals, and protection against dehydration.     

Freight distribution performance indicators for service quality planning in large transportation networks

This paper studies the use of performance indicators in routing problems to estimate how transportation cost is affected by the quality of service offered. The quality of service is assumed to be directly dependent on the size of the time windows. Smaller time windows mean better service. Three performance indicators are introduced. These indicators are calculated directly from the data without the need of a solution method. The introduced indicators are based mainly on a “request compatibility”, which describes whether two visits can be scheduled consecutively in a route. Other two indicators are introduced, which get their values from a greedy constructive heuristic. After introducing the indicators, the correlation between indicators and transportation cost is examined. It is concluded that the indicators give a good first estimation on the transportation cost incurred when providing a certain quality of service. These indicators can be calculated easily in one of the first planning steps without the need of a sophisticated solution tool. The contribution of the paper is the introduction of a simple set of performance indicators that can be used to estimate the transportation cost of a routing problem with time windows.     

Effect of proline on lactate dehydrogenase activity: testing the generality and scope of the compatibility paradigm.

The k(cat) and K(m) kinetic parameters of the labile enzyme rabbit muscle lactic dehydrogenase were determined as a function of the concentration of proline, a solute (osmolyte) accumulated in the cells of many organisms to protect them against environmental stresses. Proline is believed to protect against the stress(es) without altering the functional activity of cellular macromolecules, a property defining it as a "compatible osmolyte." In the range of 0-2 M proline, K(cat) and K(m) values for both substrates are essentially unchanged, but between 2 M and 4 M proline, k(cat) decreases by a factor of 3 to 4, whereas K(m) values are only modestly changed, if at all. These results are consistent with the proposal that compatible osmolytes do not affect functional activity, that the property of compatibility expressed by such osmolytes is generic without regard to the evolutionary history of the protein, and that the organic osmolyte concentration range over which compatibility is exhibited is extensive. In short, the results are in full accord with the principal hypothesis of "compatible osmolytes" in detail and scope.