bluuebunny/crossref_metadata_2025 huggingface dataset:
Molding of reprocessed thermoplastics with preplastication injection molding
Authors: Bedekar Manish V. , Yamazaki Kazuo , Risbud Subhash H.
Published: August 2002

The injection molding of reprocessed plastics with a preplastication plunger injection‐molding machine was investigated with a focus on the processing conditions. The process of the filling of the resin into the mold is much better controlled with preplastication than with processing in a conventional injection‐molding machine. Reprocessing of the resin leads to a reduction in molecular weight due to drastic changes in the resin morphology, thereby causing a reduction in melt viscosity. Direct experimental evidence for reduced viscosity was obtained from measurements of the filling pressure recorded on the machine and also with a melt‐flow indexer. The results of this study provide a practical solution for reducing the resin temperature when reprocessed resin is used in the injection molding of plastics. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1455–1461, 2001
Morphology and conductivity changes in a thermoplastic polyurethane‐based copolymer consisting of different soft segments
Authors: Wen Ten‐Chin , Fang Jui‐Chin , Gopalan A.
Published: August 2002

Three different segmented thermoplastic polyurethanes (TPUs) were synthesized with 4,4′‐methylenebis(phenyl isocyanate) as a hard segment and poly(ethylene glycol) (PEG) or poly(propylene glycol) (PPG) or an equal mixture of PEG and PPG with molecular 2000 as soft segments. The soft‐segment component of TPU was changed to monitor modifications in chemical and physical properties among the three TPUs. Differential scanning calorimetry (DSC) and thermogravimetric analysis were used to monitor changes in thermal characteristics. Fourier transform infrared spectroscopy (FTIR) was employed to predict the interaction between the lithium cation and the hard or soft segment in the presence of added LiClO4. The deconvolution results of spectral bands associated with the NH groups of these TPUs were used to obtain such information. Impedance spectroscopy was used to inspect the changes in the bulk conductivity of these TPUs caused by alteration of the soft‐segment component. The conductivity changes were explained through combined DSC and FTIR results. The electrochemical stability of the TPU systems was studied by linear sweep voltammetry. The results showed that the copolymer system had better thermal and electrochemical stability than the other systems. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1462–1473, 2001
Relation between electrical and mechanical properties of conducting polymer composites
Authors: Chodák Ivan , Omastová Mária , Pionteck Jürgen
Published: August 2002

The influence of the carbon black content on the mechanical and electrical properties of polypropylene/carbon black composites prepared by different processing procedures was investigated. The formation of a continuous conducting network in the insulating matrix and, consequently, the percolation threshold depend strongly on the processing route and influence both the mechanical and electrical properties of the prepared composites. An interesting coincidence of the dependencies of conductivity and elongation at break on the filler content was found. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1903–1906, 2001
Excimer formation in uniaxially stretched polymer films
Authors: Yang Jun , Li Hexian , Wang Guochang , He Binglin
Published: August 2002

The steady‐state fluorescence properties of naphthalene‐labeled polymers dispersed in poly(methyl methacrylate) (PMMA) cast films were studied under tensile loadings at 80°C. The labeled polymers were composed of methyl methacrylate (MMA) and 1‐naphthylmethyl methacrylate (NMMA). Three of the copolymers were used in this work, and the contents of NMMA were 0.59 mol % (CP1), 22.0 mol % (CP2), and 56.7 mol % (CP3), respectively. The fluorescence spectra of the films containing CP1 and CP2were unchanged during elongation. For the film containing CP3, the excited monomer emission of naphthyl groups at around 337 nm decreased with increasing applied tensile strain. The strain enhanced the emission ascribed to the excimer of the naphthyl groups in the region of 390–420 nm. The ratio of fluorescence intensities at 400 nm and 337 nm, I400/I337, increased with the applied strain, which indicates that CP3 is a sensitive probe for detecting the structural changes of polymer matrices. The obtained results mean that the excimer‐forming sites in the PMMA films during elongation depend both on the applied strain and the concentration of naphthyl groups in the dispersed polymer probes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2347–2351, 2001
Interaction of n‐alkanes with crosslinked cis‐1,4‐polybutadiene
Authors: Manikath J. J. , Francis B. , Jacob M. , Stephen R. , Joseph S. , Jose S. , Thomas S.
Published: August 2002

Permeation of n‐alkanes through cis‐1,4‐polybutadine crosslinked using conventional, efficient, and peroxide vulcanizing systems was studied by a gravimetric method. Four alkanes from n‐hexane to n‐nonane were used. In n‐octane, the studies were conducted in the temperature range of 27–70°C.The sorption data was used to estimate the diffusion and permeability coefficients, the activation energy for diffusion and permeation, the entropy and enthalpy of sorption, polymer–solvent interaction parameter, and the degree of crosslinking. The various parameters estimated indicate that permeability of the membranes depends more on the degree of crosslinking than on the nature of crosslinks. Increase in permeant chain length was found to lower permeability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2404–2413, 2001
Ethyl cellulose films as alignment layers for liquid crystals
Authors: Yan Lifeng , Zhu Qingshi , Ikeda Tomiki
Published: August 2002

Films were formed by coating hydroxypropyl cellulose (HPC) or ethyl cellulose (EC) with different kinds of solvents at high coating speeds and thin coating thicknesses. These films were used as alignment layers for liquid crystals. Atomic force microscopy (AFM) and polarizing optical microscopy (POM) were used to identify the banded texture structure of the films. The alignments of a nematic liquid crystal 5CB droplet on those films were observed by POM. Further, a novel cycle disclination line was recorded and studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2770–2774, 2001
Pervaporation separation of water/dimethylformamide mixtures using poly(vinyl alcohol)‐g‐polyacrylamide copolymeric membranes
Authors: Aminabhavi Tejraj M. , Naik Huchchuraya G.
Published: August 2002

Grafted copolymeric membranes of poly(vinyl alcohol) with acrylamide (PVA‐g‐AAm) were developed and used in the pervaporation separation of water–dimethylformamide mixtures by varying the amount of water in the feed from 0 to 100%. From these data, the permeation flux, pervaporation separation index, diffusion coefficient, swelling index, and separation selectivity were calculated at 25, 35, and 45°C. The Arrhenius activation parameters for permeation flux ranged between 22 and 63 kJ/mol, while the activation energy for diffusion ranged between 23 and 67 kJ/mol. Separation selectivity was between 15 and 22. The highest permeation flux of 0.459 kg m−2 h−1 was obtained for the 93% grafted membrane at 90% of water in the feed mixture. The results are discussed using the principles of the solution–diffusion model. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 273–282, 2002
Synthesis and application of polymeric dyes containing the anthraquinone structure
Authors: Meng Qinghua , Huang Deyin , Wei Shaohua , Chen Lin
Published: August 2002

Two polymeric dyes containing the anthraquinone structure were prepared via solution polycondensation. Their monomers were prepared through reactions between 1,5‐dichloroanthraquinone and nucleophiles. The polymeric dyes were characterized with NMR and thermogravimetry. Their ultraviolet spectra, intrinsic viscosity, and solubility were also measured. Then, the polymeric dyes were applied to the mass coloration of poly(ethylene terephthalate) with good compatibility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1252–1257, 2002
Aspects of pollution on the coastal ecosystems of the Mediterranean Sea
Authors: Bonotto Silvano
Published: August 2002

1. Various forms of pollution are threatening marine habitats and species.

2. Evidence of the impacts of different pollutants can be seen with the demise of a wide range of species from the monk seal and dolphins to increases in the frequency of algal blooms.

3. Various algae have been used to monitor specific pollutants and the widespread use of Acetabularia spp. as indicator species is proposed. Copyright © 2001 John Wiley & Sons, Ltd.
Tissue engineering strategies for adipose tissue repair
Authors: Patrick C.W.
Published: August 2002

Tissue engineering is a relatively young field that combines engineering, clinical science, and life sciences to, in part, repair or regrow tissues. Adipose tissue has recently become a focus area for tissue engineering, encouraged by the large number of reconstructive, cosmetic, and correctional indications that could be addressed with clinically translatable adipose tissue engineering strategies. This review discusses the three aspects of an adipose construct, namely cell types, scaffold, and microenvironment, and presents current tissue engineering strategies under pursuit. Anat Rec 263:361–366, 2001. © 2001 Wiley‐Liss, Inc.
Engineering of vascular ingrowth matrices: Are protein domains an alternative to peptides?
Authors: Merzkirch Christoph , Davies Neil , Zilla Peter
Published: August 2002

Anastomotic intimal hyperplasia and surface thrombogenicity are the main reasons for the high failure rate of prosthetic small‐diameter vascular grafts. While anastomotic intimal hyperplasia is a multifactorial event, ongoing surface thrombogenicity is primarily caused by the lack of an endothelium, even after years of clinical implantation. After decades of poorly performing synthetic artery‐grafts, tissue engineering has emerged as a promising approach to generate biologically functional bio‐synthetic hybrid grafts mimicking native arteries regarding the presence of an endothelial lining on the blood surface. “In vitro endothelialization” represented the first generation of such tissue‐engineered vascular grafts, utilising cell culture techniques for the creation of a confluent autologous endothelium on ePTFE grafts. The clinical long‐term results with this method in almost 200 patients are highly encouraging, showing patencies equal to vein grafts. Since “in vitro endothelialization” requires cell culture facilities, it will always be confined to large centres. Therefore, research of the 1990s turned to the development of spontaneously endothelializing implants, to make tissue‐engineered grafts amenable to the entire vascular‐surgical community. Apart from scaffold designs allowing transmural ingrowth, biological signalling through a facilitating ingrowth matrix holds a key to spontaneous endothelialization. In biological signalling, the increasingly deeper understanding of bio‐active molecules and the discovery of domains and peptide sequences during the 1980s created the expectation in the 1990s that peptide signalling may be all that is needed. This present review highlights the possible problems associated with such a reductionist approach. Using the fibronectin molecule, we demonstrated that domains may be more suitable modules in tissue engineering than peptide sequences. Anat Rec 263:379–387, 2001. © 2001 Wiley‐Liss, Inc.
Acidic cysteine endoproteinase cathepsin K in the degeneration of the superficial articular hyaline cartilage in osteoarthritis
Authors: Konttinen Yrjö T. , Mandelin Jami , Li Tian‐Fang , Salo Jari , Lassus Jan , Liljeström Mikko , Hukkanen Mika , Takagi Michiaki , Virtanen Ismo , Santavirta Seppo
Published: August 2002

Objective

To measure cartilage pH in patients with osteoarthritis (OA) and to analyze the presence of cathepsin K, the recently discovered acidic endoproteinase, in phenotypically altered chondrocytes.

Methods

Intraoperative measurements of the pH of clinically normal, fibrillated, superficially fissured, and deeply fissured cartilage surfaces (grades 0–3, respectively) in OA patients undergoing primary hip replacement surgery were performed with the use of a sting electrode sterilized with microbicidic plasma. Fluorescent pH probes were used for in situ assessment of cartilage matrix pH. Cathepsin K was assessed using quantitative reverse transcriptase–polymerase chain reaction and immunohistochemistry methods.

Results

The pH of grade 0 cartilage surfaces was 7.1 ± 0.4 (mean ± SD), compared with 6.2 ± 0.9 (P < 0.05), 5.7 ± 1.0 (P < 0.001), and 5.5 ± 1.0 (P < 0.001) for grades 1–3 cartilage surfaces, respectively. Fluorescent pH probes and acid‐dependent autocatalytic conversion of cathepsin K into its active, low molecular weight form in cartilage confirmed these findings. Cathepsin K messenger RNA levels increased in relation to the severity of OA, and the number of cathepsin K–containing chondrocytes increased from a mean ± SD of 12 ± 3 in grade 0 cartilage surfaces to 47 ± 7, 50 ± 6, and 100 ± 12 in grades 1–3 cartilage surfaces, respectively (P < 0.001 for all comparisons).

Conclusion

Acid‐activated, but pharmacologically inhibitable, cathepsin K is induced in phenotypically altered chondrocytes in OA. The findings suggest that cathepsin K, rather than neutral matrix metalloproteinases, degrades the superficial gliding surfaces of the articular hyaline cartilage in OA.
On prices' evolutions based on geometric telegrapher's process
Authors: Di Crescenzo Antonio , Pellerey Franco
Published: August 2002

The geometric telegrapher's process is proposed as a model to describe the dynamics of the price of risky assets. When the underlying random inter‐times have Erlang distribution we express the probability law of such process in terms of a suitable two‐index pseudo‐Bessel function. Stochastic comparisons of two geometric telegrapher's processes based on the usual stochastic order (FSD comparison) and on the stop‐loss order are also performed. Various examples of application of such comparisons are then provided. Copyright © 2002 John Wiley & Sons, Ltd.
Subacute toxicities and toxicokinetics of a new erectogenic, DA‐8159, after single and 4‐week repeated oral administration in dogs
Authors: Shim Hyun J. , Lee Eun J. , Kim Jung H. , Kim Soon H. , Kwon Jong W. , Kim Won B. , Cha Shin‐W. , Lee Myung G.
Published: August 2002

The subacute toxicities and toxicokinetics of a new erectogenic, DA‐8159, were evaluated after single (at the 1st day) and 4‐week (at the 28th day) oral administration of the drug, in doses of 0 (to serve as a control), 12.5, 50 and 200 mg/kg/day, to male and female dogs (n=3 for male and female dogs for each dose). DA‐8159 had an effect on the immune‐related organs (or tissues), circulatory systems, liver, adrenal glands, ovaries and pancreas. The toxic dose was 200 mg/kg and no observed adverse effect level was less than 50 mg/kg for male and female dogs. There were no significant gender differences in the pharmacokinetic parameters of DA‐8159 for each dose after both single and 4‐week oral administration. The pharmacokinetic parameters of DA‐8159 were dose‐independent after single oral administration; the time to reach a peak plasma concentration (Tmax) and the dose‐normalized area under the plasma concentration–time curve from time zero to 24 h in plasma (AUC0–24 h) were not significantly different among three doses. However, accumulation of DA‐8159 after 4‐week oral administration was considerable at toxic dose, 200 mg/kg/day. For example, after 4‐week administration, the dose‐normalized AUC0–24 h value at 200 mg/kg/day (4.71 and 15.3 μg h/ml) was significantly greater than that at 12.5 mg/kg/day. After 4‐week oral administration, the dose‐normalized Cmax and AUC0–24 h at 200 mg/kg/day were significantly higher and greater, respectively, than those after a single oral administration. Copyright © 2001 John Wiley & Sons, Ltd.
Quantification of urinary excretion of ethosuximide enantiomers and their major metabolites in the rat
Authors: Mifsud J. , Millership J.S. , Collier P.S. , Morrow R. , Hamilton J.T.G. , McRoberts W.C.
Published: August 2002

A chiral gas chromatographic assay has been developed for quantitative analysis of ethosuximide and its major metabolites in rat urine. The extraction procedure was found to be precise and reproducible. Recovery was in the range of 94–98%, intraday CV(%) was 0.92% for (S)‐ethosuximide (50 μg/ml) and 0.51% for (R)‐ethosuximide (50 μg/ml). Interday CV(%) was 1.12% for (S)‐ethosuximide and 0.72% for (R)‐ethosuximide. The limit of detection was determined to be around 0.01 μg/ml for each enantiomer. Following administration of rac‐ethosuximide by i.v., i.p. and oral routes, unchanged ethosuximide was detected in urine up to 72 h after drug administration. The appearance of all detected metabolites occurred within 24 h of drug administration. Significantly more (S)‐ethosuximide was excreted unchanged than (R)‐ethosuximide with all three routes studied. A substantial amount of the drug was eliminated as the 2‐(1‐hydroxyethyl)‐2‐methylsuccinimide (2 pairs of diastereoisomers). Much less drug was eliminated as the 2‐ethyl‐3‐hydroxy‐2‐methylsuccinimide with only one diastereoisomer observed. Examination of the one pair of diastereoisomers of 2‐(1‐hydroxyethyl)‐2‐methylsuccinimide that was resolved showed preferential excretion of one isomer. Comparison of both pairs of diastereoisomers showed that one pair was formed in preference to the other with a ratio of approximately 0.8:1. It is concluded that stereoselective metabolism of ethosuximide occurs. Copyright © 2001 John Wiley & Sons, Ltd.
Capillary electrophoretic analysis of proteins and peptides of biomedical and pharmacological interest
Authors: Righetti Pier Giorgio
Published: August 2002

Capillary electrophoresis (CE) is an automated approach to electrokinetic separations that has had a deep impact in all fields of life sciences, including biomedical and biotechnological research and clinical and forensic practice. The present review highlights aspects of peptides and proteins separations, with particular emphasis on macromolecular analytes of biomedical interest. Among the various CE techniques available, a novel methodology is here illustrated consisting in separations in acidic, isoelectric buffers, which have the advantage of protonating the silica wall, thus minimizing interactions of proteinaceous material with the siliceous surface, while allowing delivery of high voltage gradients, due to their low conductivities. The review ends with applications of CE to the analysis of folding/unfolding/refolding/misfolding of proteins, a field which has deep implications in the biomedical arena, since it is connected to a host of disorders, such as prion protein diseases. Copyright © 2001 John Wiley & Sons, Ltd.
Amlodipine bioequivalence study: quantification by liquid chromatography coupled to tandem mass spectrometry
Authors: Carvalho M. , Oliveira C.H. , Mendes G.D. , Sucupira M. , Moraes M.E.A. , De Nucci G.
Published: August 2002

Objective—To assess the bioequivalence of two amlodipine tablet formulations (Amlodipine® 5 mg tablet from Merck S.A. Indústrias Químicas, Brazil as test formulation and Norvasc® 5 mg tablet from Laboratórios Pfizer Ltd., Brazil as reference formulation) in 24 healthy volunteers of both sexes.

Methods—The study was conducted using an open, randomized two‐period crossover design with a 4‐week washout interval. Plasma samples were obtained over a 144 h period. Plasma amlodipine concentrations were analyzed by combined liquid chromatography coupled to tandem mass spectrometry (LC‐MS‐MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). From the amlodipine plasma concentration vs time curves, the following pharmacokinetic parameters were obtained: AUClast, AUC0–inf and Cmax. The statistical interval proposed was 80–125% according to the US Food and Drug Administration Agency.

Results—The limit of quantification was 0.1 ng/ml for plasma amlodipine analysis. The geometric mean and the 90% confidence interval (CI) test/reference ratios were 101.2 (92.9–110.2%) for AUClast, 99.6 (91.5–108.4%) for AUC0–inf and 98.5 (89.0–109.1%) for Cmax.

Conclusion—Since the 90% CI for AUClast, AUC0–inf and Cmax ratios were within in the 80–125% interval proposed by the US FDA, it was concluded that Amlodipine® 5 mg tablet (test formulation) was bioequivalent to Norvasc® 5 mg tablet, in terms of both rate and extent of absorption. Copyright © 2001 John Wiley & Sons, Ltd.
Induced current measurements in whole body exposure condition to radio frequency electric fields
Authors: Wilén Jonna , Mild Kjell Hansson , Paulsson Lars‐Erik , Anger Gert
Published: August 2002

The current induced in a human exposed to radio frequency electric fields has been studied by the use of a stripline, in which whole body exposure to vertical electric fields (3–27 MHz) can be produced. We have examined two different techniques to measure the induced current; parallel plate meters and current probes. When the subject has good connection to the ground, the choice of measurement technique is not crucial, since there are only minor differences in readings between the instruments. But when the subject is wearing shoes and/or standing on a wooden plate, the difference between the instruments increases considerably. The difference can mainly be explained by the capacitive coupling between the parallel plate meters and the ground; therefore, the current probes are preferred when the subject does not have perfect contact with the ground. Since the International Commission on Non‐Ionizing Radiation Protection guidelines demand measurements of induced current in humans exposed to radio frequency fields in the range of 10–110 MHz, the importance of finding an appropriate measurement procedure becomes apparent. Bioelectromagnetics 22:560–567, 2001. © 2001 Wiley‐Liss, Inc.
When Ets transcription factors meet their partners
Authors: Verger Alexis , Duterque‐Coquillaud Martine
Published: August 2002

Ets proteins are a family of transcription factors that regulate the expression of a myriad of genes in a variety of tissues and cell types. This functional versatility emerges from their interactions with other structurally unrelated transcription factors. Indeed, combinatorial control is a characteristic property of Ets family members, involving interactions between Ets and other key transcriptional factors such as AP1, SRF, and Pax family members. Intriguingly, recent molecular modeling and crystallographic data suggest that not only the ETS DNA‐binding domain, but also the DNA recognition helix α3, are often directly required for Ets partner's selection. Indeed, while most DNA‐binding proteins appear to exploit differences within their DNA recognition helices for sites selection, the Ets proteins exploit differences in their surfaces that interact with other transcription factors, which in turn may modify their DNA‐binding properties in a promoter‐specific fashion. Taken together, the gene‐specific architecture of these unique complexes can mediate the selective control of transcriptional activity. BioEssays 24:362–370, 2002. ©2002 Wiley Periodicals, Inc.
Human infertility, reproductive cloning and nuclear transfer: a confusion of meanings
Authors: Kubiak Jacek Z. , Johnson Martin H.
Published: August 2002

The Chief Medical Officer of Health of the United Kingdom has recommended that the 1990 Human Fertilisation and Embryology Act should be amended to allow cloning in humans for research purposes only. He also recommended that: “The transfer of an embryo created by cell nuclear replacement into the uterus of a woman (so called ‘reproductive cloning’) should remain a criminal offence” (recommendation 7, Ref. 1). This recommendation implies that nuclear replacement and cloning are the same. They are not. Nuclear transfer constitutes reproductive cloning only when the individual created is genetically identical to the nuclear donor. In this paper, we describe a possible future use of nuclear transfer for the treatment of infertile individuals. The treatment yields an individual that receives approximately equal genetic contributions from each parent. We use this example to illustrate how semantic confusion might lead to plausibly moral and justifiable treatments being legally banned. In doing so, we hope to encourage a more accurate and informed use of language in science, law and politics, so that legislation is properly informed by science and achieves what it intends. BioEssays 23:359–364, 2001. © 2001 John Wiley & Sons, Inc.
Steroid‐triggered death by autophagy
Authors: Thummel Carl S.
Published: August 2002

Programmed cell death is a critical part of normal development, removing obsolete tissues or cells and sculpting body parts to assume their appropriate form and function. Most programmed cell death occurs by apoptosis of individual cells or autophagy of groups of cells. Although these pathways have distinct morphological characteristics, they also have a number of features in common, suggesting some overlap in their regulation. A recent paper by Lee and Baehrecke provides further support for this proposal.(1) These authors present, for the first time, a genetic analysis of autophagy, using the steroid‐triggered metamorphosis of Drosophila as a model system. They demonstrate a remarkable degree of overlap between the control of apoptosis and autophagy as well as a key role for the steroid‐inducible gene E93 in directing the autophagic death response. This paper also shows that E93 can direct cell death independently from the known death‐inducer genes, defining a novel death pathway in Drosophila. BioEssays 23:677–682, 2001. © 2001 John Wiley & Sons, Inc.
Increasing the specificity of the forensic luminol test for blood
Authors: Quickenden Terence I. , Cooper Paul D.
Published: August 2002

It is shown that the presumptive luminol chemiluminescence test for the presence of traces of blood can be made more determinative by measuring the peak emission wavelength of the luminol chemiluminescence. When sprayed onto a surface containing traces of human haemoglobin, a 1 g/L solution of aqueous luminol containing 7 g/L sodium perborate gives an emission peak at 455 ± 2 nm, whereas the same mixture gives an emission peak at 430 ± 3 nm when sprayed onto a surface containing traces of sodium hypochlorite (household bleach). This spectral difference can readily be determined using spectroscopic equipment that either scans the spectrum before significant luminescence decay occurs or corrects the spectrum for the effects of any decay. It was found that bovine haemoglobin and human haemoglobin showed no significant spectral differences. Copyright © 2001 John Wiley & Sons, Ltd.
Solid‐state NMR relaxation studies of Australian spider silks
Authors: Kishore A. I. , Herberstein M. E. , Craig C. L. , Separovic F.
Published: August 2002

Solid‐state NMR techniques were used to study two different types of spider silk from two Australian orb‐web spider species, Nephila edulis and Argiope keyserlingi. A comparison of 13C‐T1 and 1H‐T1ρ solid‐state NMR relaxation data of the Ala Cα, Ala Cβ, Gly Cα, and carbonyl resonances revealed subtle differences between dragline and cocoon silk. 13C‐T1ρ and 1H‐T1 relaxation experiments showed significant differences between silks of the two species with possible structural variations. Comparison of our data to previous 13C‐T1 relaxation studies of silk from Nephila clavipes (A. Simmons et al., Macromolecules, 1994, Vol. 27, pp. 5235–5237) also supports the finding that differences in molecular mobility of dragline silk exist between species. Interspecies differences in silk structure may be due to different functional properties. Relaxation studies performed on wet (supercontracted) and dry silks showed that the degree of hydration affects relaxation properties, and hence changes in molecular mobility are correlated with functional properties of silk. © 2002 Wiley Periodicals, Inc. Biopolymers 61: 287–297, 2002
Surface immobilization of galactose onto aliphatic biodegradable polymers for hepatocyte culture
Authors: Yoon Jun Jin , Nam Yoon Sung , Kim Jung Hoe , Park Tae Gwan
Published: August 2002

A novel surface modification method of biodegradable polymers was investigated for inducing the attachment of specific cells onto the polymer surface via ligand‐receptor interactions. Galactose, a targeting ligand specific to asialoglycoprotein receptors present on cell membrane of hepatocytes, was introduced on the surface of poly(D,L‐lactic‐co‐glycolic acid) (PLGA) films. A terminal end group of carboxylic acid in PLGA was activated by dicyclohexylcarbodiimide and N‐hydroxysuccinimide for the direct conjugation of lactose by reductive amination reaction. Di‐block copolymers of PLGA‐b‐poly(ethylene glycol) (PEG) having a free terminal amine group were also synthesized and used for the conjugation of galactose for the introduction of a PEG spacer between PLGA and galactose. The presence of galactose moieties on the blend film surface was characterized by measuring water contact angle and X‐ray photon spectroscopy, and the amount of galactose was indirectly determined by a specific lectin‐binding assay. With increasing the galactose concentration on the blend film surface, the initial attachment as well as the cell viability of hepatocyates concomitantly increased. The introduction of PEG spacer reduced the cell attachment and viability. Albumin secretion rate from hepatocytes was enhanced for galactose modified surfaces, whereas it was reduced for the surfaces not having galactose moieties. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 1–10, 2002; DOI 10.1002/bit.10239
Mass‐transfer limitations for immobilized enzyme‐catalyzed kinetic resolution of racemate in a fixed‐bed reactor
Authors: Xiu Guo‐Hua , Jiang Lei , Li Ping
Published: August 2002

A mathematical model has been developed for immobilized enzyme‐catalyzed kinetic resolution of racemate in a fixed‐bed reactor in which the enzyme‐catalyzed reaction (the irreversible uni–uni competitive Michaelis–Menten kinetics is chosen as an example) was coupled with intraparticle diffusion, external mass transfer, and axial dispersion. The effects of mass‐transfer limitations, competitive inhibition of substrates, deactivation on the enzyme effective enantioselectivity, and the optical purity and yield of the desired product are examined quantitatively over a wide range of parameters using the orthogonal collocation method. For a first‐order reaction, an analytical solution is derived from the mathematical model for slab‐, cylindrical‐, and spherical‐enzyme supports. Based on the analytical solution for the steady‐state resolution process, a new concise formulation is presented to predict quantitatively the mass‐transfer limitations on enzyme effective enantioselectivity and optical purity and yield of the desired product for a continuous steady‐state kinetic resolution process in a fixed‐bed reactor. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 29–39, 2001.
Rapid high‐performance liquid chromatographic assay of dorzolamide in rabbit aqueous humor
Authors: Maltese Adriana , Bucolo Claudio
Published: August 2002

A rapid high‐performance liquid chromatographic method using a C18 reversed‐phase column (Hypersil ODS) with UV detection at 254 nm and a simple pre‐treatment of samples is presented for the analysis of dorzolamide, a carbonic anhydrase inhibitor, in rabbit aqueous humor. A water solution containing 2% ZnSO4·7H2O was used to deproteinize aqueous humor samples. The mobile phase consisted of 7% CH3CN and 93% of a solution containing 1% TEA adjusted to pH = 3.5 with H3PO4. Paracetamol was found to be a suitable internal standard. The standard curves were linear in the detection range. The precision and the accuracy were <5% for both intra‐ and inter‐day assays. Copyright © 2002 John Wiley & Sons, Ltd.
Measurement and pharmacokinetic analysis of unbound cephaloridine in rat blood by on‐line microdialysis and microbore liquid chromatography
Authors: Tsai T.H. , Kao H.Y. , Chen C.F.
Published: August 2002

A technique involving rapid sampling of cephaloridine in rat blood was achieved using a combination of microdialysis and sensitive microbore liquid chromatography. A microdialysis probe was inserted into the jugular vein/right atrium of a Sprague–Dawley rat. Then after a real‐time collection of the analyte by microdialysis, the dialysate was automatically injected into a liquid chromatographic system via an on‐line injector. Following a 2 h stabilization period after the surgical procedure, cephaloridine (20 mg/kg, i.v.) was then administered via the femoral vein. Isocratic elution of cephaloridine was carried out with a mobile phase containing methanol–20 mM monosodium phosphate (25:75, v/v, pH 5.5), and the flow rate of the mobile phase was 0.05 mL/min within 10 min. Intra‐ and inter‐assay accuracy and precision of the assay were each less than 10%. The in vivo recovery of the cephaloridine from the microdialysate was 49.7 ± 8.0% and 42.4 ± 8.4% for 0.5 and 1 µg/mL standards (n = 6), respectively. Based on the pharmacokinetic analysis, the elimination half‐life was 32.2 ± 8.6 min by cephaloridine administration (20 mg/kg, i.v., n = 6). Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ACD

acid citrate dextrose

AUC

area under the curve

AUMC

area under the moment vs time curve

MRT

mean residence time
Determination of amphetamine in dog plasma by gas chromatography with mass selective detection
Authors: March C. , Karnes H. T. , McLean A. , Mukherjee P. S.
Published: August 2002

This paper describes the validation of an analytical method for the determination of amphetamine in beagle dog plasma by gas chromatography coupled to mass spectrometry (GC‐MS). d‐Amphetamine‐d6 was used as the internal standard. The method consisted of a rapid single‐step liquid–liquid extraction and derivatization of amphetamine with 2,2,2‐trichloroethyl chloroformate, followed by sensitive GC‐MS detection. This is the first report utilizing the combination of trichloroethyl chloroformate as a derivatization reagent and a deuterated amphetamine analog as an IS for the quantification of amphetamine in plasma. The method was validated in terms of specificity, curve fit, precision, accuracy, recovery and stability, and was acceptable according to FDA draft guidelines for validation of bioanalytical methods. The limit of detection was 0.65 ng/mL. The calibration range was 5–150 ng/mL. The validated method was successfully employed for the quantitation of amphetamine in dog plasma samples for pharmacokinetic profiling. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

% DFN

percentage difference from nominal

QC

quality control
Anatomical study to investigate the feasibility of pedicled nerve, free vessel gastrocnemius muscle transfer for restoration of biceps function
Authors: Cogswell Lucy Katharine , Giele Henk
Published: August 2002

A challenging problem is the patient with a total brachial plexus injury with nerve root avulsions. In these patients nerve repair is not possible and no local functioning muscles are available for transfer. Current techniques involve either nerve repair using donor nerves from the contralateral limb or free muscle transfer neurotized by intercostal nerves. The problem with both these techniques is that they are dependent on neural regeneration, which is imperfect.

To overcome the problem we propose a technique of transferring a distant muscle whilst retaining its neural supply. Gastrocnemius is a strong muscle and one suitable for free tissue transfer. This study assessed the possibility of transferring gastrocnemius on its neural supply by determining the length of nerve available and whether it was possible to dissect the nerve to gastrocnemius from the main body of the sciatic nerve. We found that the latter was possible, and that the length of dissected nerve would allow transfer of the innervated muscle from the calf to the axilla. Clin. Anat. 14:242–245, 2001. © 2001 Wiley‐Liss, Inc.
Reconstruction of the articular facets of the subtalar and talonavicular joints from volumetric magnetic resonance data
Authors: Ward Kathryn Anna , Willott Jake , Paxton Stephen , Soames Roger William
Published: August 2002

Image processing methods have been used to visualize the articular surfaces of an intact foot from an MR scan and to allow the relationship between the joint surfaces to be studied. The MR protocol employed would be applicable in the living foot. Several standard image‐processing methods have been used to develop protocols for manual and automated editing of a volumetric MR scan. The result is a volume‐rendered foot, displaying the articular surfaces of the tarsal and metatarsal joints. The methods employed are discussed and reconstructions of the subtalar and talonavicular joints presented, thereby enabling a qualitative analysis of the facets on the talus, calcaneus and navicular. Clin. Anat. 14:272–277, 2001. © 2001 Wiley‐Liss, Inc.
Effects of pentoxifylline on the different steps during adhesion and transendothelial migration of flowing neutrophils
Authors: Bahra P.S. , Rainger G.E. , Wautier J.‐L. , Nash G.B.
Published: August 2002

We used a flow system to observe the stepwise adhesion and migration of neutrophils on cultured human umbilical vein endothelial cells (HUVEC) stimulated with tumour necrosis factor‐α (TNF) for 4 h, and to evaluate the effects of pentoxifylline (PTX) at each step. When HUVEC had been stimulated with 100 U ml−1 TNF, treatment of neutrophils with PTX did not reduce the number captured from flow but did cause nearly all adherent cells ( > 90%) to roll, whereas most untreated cells became immobilized and ∼30% transmigrated within minutes. On washout of the PTX, many rolling cells halted and started to migrate. Treatment of the HUVEC with PTX at the same time as 100 U ml−1 TNF did not affect the number of neutrophils adhering, but there was a significant increase in the percentage of cells rolling even though PTX was no longer present. Thus PTX reduced presentation of activating agents by HUVEC, as well as inhibiting the response by neutrophils to surface‐presented activating agent(s). If HUVEC were stimulated with 10 U ml−1 TNF with PTX, the adhesion of flowing neutrophils was greatly inhibited compared to TNF alone. Surface ELISA indicated that PTX reduced TNF‐induced upregulation of E‐selectin. This reduction was only sufficient to reduce capture of neutrophils at the low dose of TNF. Thus, by using a flow‐based model, we have been able to separate the effects of a multipotent agent such as pentoxifylline, which acts on leucocytes and endothelial cells, at each stage of migration. Copyright © 2001 John Wiley & Sons, Ltd.
Effect of cerebrocrast on the function of human platelets and release of the arachidonic acid from plasma membrane
Authors: Briede Janīna , Heidemanis Kārlis , Dabina Inese , Duburs Gunārs
Published: August 2002

Diabetes mellitus (DM) is accompanied by several cardiovascular complications such as coronary artery disease, atherosclerosis, hypertension, cerebral and myocardial infarction, etc. DM induces the alteration of platelet functions including activation, hyperaggregation, adhesiveness, and formation of thrombi. Release of AA from phospholipids of the PM, synthesis of TxA2,PGE2, activity of PLA2, and PLC are increased in the platelets of the DM patients. Stimulation of PLA2 activity and accumulation of bioactive metabolites such as AA, its oxygenated derivatives, prostaglandins and PAF can evoke glucose production, also. In this study we explored the effect of the 1,4‐dihydropyridine compound cerebrocrast at a low concentration (10−6–10−8M) on the level of intracellular calcium in unstimulated human platelets and those stimulated with thrombin as well as release of [3H] AA from phospholipids of platelet PM. Cerebrocrast at a concentration of 10−6 M decreased the basal level of intracellular calcium concentration (platelets were loaded with Fura‐2) in unstimulated as well as in thrombin stimulated platelets. Cerebrocrast at concentrations of 10−6, 10−7, 10−8 M inhibited release of [3H] AA from phospholipids of platelet PM. We conclude that blockade of human platelet activation with cerebrocrast can prevent aggregation, adhesion and formation of thrombi. The inhibition of [3H] AA release from phospholipids of platelet PM can prevent formation of eicosanoids such as TxA2, PGG2, and PGH2 plus AA oxygenated derivatives. These effects of cerebrocrast are very significant in the treatment of DM‐evoked cardiovascular complications. Copyright © 2002 John Wiley & Sons, Ltd.
Impact of abciximab versus tirofiban on hospital length of stay for PCI patients
Authors: Lage Maureen J. , Barber Beth L. , McCollam Patrick L. , Bala Mohan , Scherer Joel
Published: August 2002

The purpose of this retrospective study was to examine in a naturalistic setting the effect of abciximab versus tirofiban on hospital length of stay for patients undergoing percutaneous coronary intervention (PCI). Retrospective data were obtained from HCIASach's Clinical Pathways Database on 5,560 PCI patients who were administered either abciximab or tirofiban. Multivariate analysis was used to control for a wide range of factors (GPIIb/IIIa selection, patient demographics, insurance provider, health conditions, admission information, and hospital characteristics) that may influence hospital length of stay. Estimation was conducted via a two‐stage sample selection model. After controlling for high‐risk indications and sources of selection bias, results indicate that receipt of abciximab was associated with significantly shorter lengths of hospital stays compared to tirofiban (1.01 fewer days; p < 0.001). In a subgroup analysis of patients having an acute myocardial infarction (AMI; n = 2,593), receipt of abciximab was also found to be associated with significantly shorter hospital stays compared to tirofiban (0.60 fewer days; p < 0.001). Results of this study indicate that patients who are administered abciximab versus tirofiban have significantly shorter hospital stays. This reduction in length of stay may imply potential cost offsets for PCI patients who receive abciximab. Cathet Cardiovasc Intervent 2001;52:298–305. © 2001 Wiley‐Liss, Inc.
Suitability of the Cordis Stabilizer™ marker guide wire for quantitative coronary angiography calibration: An in vitro and in vivo study
Authors: Koning G. , Hekking E. , Kemppainen J.S. , Richardson G.A. , Rothman M.T. , Reiber J.H.C.
Published: August 2002

Catheters usually are used for calibration purposes in quantitative coronary angiography (QCA). The systematic and random errors in these calibration factors (CFs) are dependent on the size and quality of the catheters and limited by out‐of‐plane magnification (OPM). Theoretically, a guide wire with evenly spaced marker bands would solve many of these potential problems. For this reason, we tested the Cordis Stabilizer™ marker wire, featuring 10 radiopaque platinum marker bands 15 mm apart, in in vitro and in vivo studies. To assess the effect of foreshortening, wires were positioned in a tube phantom; a centimeter grid was used as the gold standard. Radiographic images were acquired at 5‐inch and 7‐inch image‐intensifier sizes, 5122 and 1,0242 matrix sizes and angulations from 0° to 70° in steps of 10°. It was concluded that the relative errors in CFs are less than 7% if the foreshortening angles remain less than 20°. In DICOM images of 15 patients, 65 measurements were taken after calibration on an 8F catheter and on a guide wire positioned in the coronary lesion. In all but two cases, the wire CFs were larger than the catheter CFs (relative difference, 24.7 ± 19.6%). The measurements were divided into four groups: (I) no apparent OPM or foreshortening (n = 7), (II) only OPM (n = 4), (III) only foreshortening (n = 10), and (IV) the combination of both (n = 44). In group I (no OPM or foreshortening) the QCA results were similar using the guide wire or catheter as the calibration device (relative CF difference, 2.9% only). In group III the diameters were overestimated using the guide wire (obstruction diameter difference, 0.22 ± 0.11 mm; reference diameter difference, 0.35 ± 0.06 mm). For only OPM (group II) and the combination of OPM and foreshortening (group IV), the lesion length was underestimated on average by 2.4 mm using the catheter instead of the guide wire. In conclusion, if accurate assessment of the lesion length is important, the marker wire should be used for calibration purposes. For vessel diameter measurements, the conventional catheter calibration approach is the method of choice. Cathet Cardiovasc Intervent 2001;52:334–341. © 2001 Wiley‐Liss, Inc.
Percutaneous stent placement as treatment for an infant with superior vena cava syndrome
Authors: Frias Patricio A. , Johns James A. , Drinkwater Davis C. , Doyle Thomas P.
Published: August 2002

The percutaneous use of stents for the treatment of superior vena cava (SVC) syndrome is well described in the adult population. We report the successful use of intravascular stents to treat an infant with severe SVC syndrome. Cathet Cardiovasc Intervent 2001;52:355–358. © 2001 Wiley‐Liss, Inc.
Brachytherapy for in‐stent restenosis through the internal mammary artery
Authors: Kobayashi Yoshio , Moses Jeffrey W. , Collins Michael , Colombo Antonio , Leon Martin B. , Teirstein Paul S.
Published: August 2002

We report five cases treated with brachytherapy through the internal mammary artery (IMA) for in‐stent restenosis at the distal anastomosis (n = 3) and in the left anterior descending coronary artery beyond the distal anastomosis (n = 2). After angioplasty, catheter‐based gamma radiation was performed. There was no delivery failure of the radiation system. All cases had angiographic success and no procedural or in‐hospital complications. Cathet Cardiovasc Intervent 2001;53:530–534. © 2001 Wiley‐Liss, Inc.
Multicentre, prospective, randomized trial of 4 vs. 6 French catheters in 410 patients undergoing coronary angiography
Authors: Todd Derick M. , Hubner Peter J. , Hudson Norah , Sarma Jaydeep , McCance Alastair J. , Caplin John
Published: August 2002

The aim of this study was to assess the quality of angiograms obtained using 4 Fr catheters compared with 6 Fr catheters, the ease of use of the 4 Fr catheters, and the safety of patient mobilization 1 hr following 4 Fr angiography. Details of catheter performance and procedural details were recorded at the time of the angiogram. The angiographic images were scored on the quality and completeness of vessel opacification throughout systole and diastole. A total of 410 patients were recruited. There was no difference between 4 and 6 Fr for procedural variables. All angiograms were considered to be of diagnostic quality. The angiographic scores for the right coronary artery and left ventricular injections were no different between 4 and 6 Fr. However, the angiographic scores for the left anterior descending and circumflex arteries were lower with 4 than with 6 Fr (both P < 0.05). Patients who had 4 Fr angiography mobilized safely at 1 hr and reported significantly less discomfort and bruising than 6 Fr patients. Good‐quality diagnostic coronary angiograms can be achieved using 4 Fr catheters with the advantage of earlier postprocedural mobilization and reduced discomfort and bruising for the patient. Cathet Cardiovasc Intervent 2001;54:269–275. © 2001 Wiley‐Liss, Inc.
Non‐flow limiting dissection leading to late coronary restenosis following intracoronary brachytherapy
Authors: McClean Dougal R. , Thomas Martyn R.
Published: August 2002

We report a coronary dissection detected during routine repeat angiography 6 months following balloon angioplasty and intracoronary radiation. No dissection was seen immediately following the initial procedure. Subsequent late healing of the dissection led to marked restenosis and the development of angina 14 months after the index procedure. Cathet Cardiovasc Intervent 2001;54:355–357. © 2001 Wiley‐Liss, Inc.