bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Sialoadenectomy and Epidermal Growth Factor Administration on Liver Regeneration After Partial Hepatectomy
Authors: Lambotte L , Saliez A , Triest S , Maiter D , Baranski A , Barker A , Li B
Published: August 2004

Epidermal growth factor (EGF), a mitogen in vitro for hepatocytes, produces in various cell lines changes similar to those observed very rapidly in hepatocytes after partial hepatectomy (PH). These changes include ion movements, membrane hyperpolarization and proto–oncogene expression. A stimulatory effect of EGF on liver regeneration can therefore tentatively be associated with the events occurring within the first 3 hours after a PH, sometimes referred to as the “priming phase.” To assess this hypothesis, we examined in Wistar rats the effect of EGF deprivation produced by sialoadenectomy (SX) performed before or after a PH of 70%. SX at the time of PH significantly decreased the 3H–thymidine uptake in the DNA 24 hours later (147 ± 14 DPM per microgram of DNA, mean ± SE) compared with a simple PH (322 ± 16; P < .01), but also compared with results obtained when PH is combined with a sham sialoadenectomy (SSX) or in rats pair–fed with the sialoadenectomized rats. This incomplete inhibition was confirmed by a decreased rise in thymidine kinase (TK) activity and by reduced proliferating cell nuclear antigen (PCNA) labeling and mitotic indices 30 hours after PH. By contrast, SX did not inhibit the early expression of c–jun and c–fos, or of c–myc, 30 or 120 minutes after PH, respectively. A reduction of DNA synthesis was also obtained when SX was performed 3 hours after PH (127 ± 15 DPM per microgram of DNA vs. 350 ± 21 in SSX; P < .001) but not when SX was delayed until the 6th or the 17th hour after PH. It was sufficient to administer EGF (40 microg) from the third to the ninth hour to correct the reduction of [3H]thymidine uptake in rats sialoadenectomized before PH. These results indicate that the diminished EGF availability following SX decreases or at least delays liver regeneration, and that the effect of EGF on liver regeneration does not seem related to the early changes of proto–oncogene expression, but rather to events occuring later, at the time of reported internalization and binding of EGF to its nuclear receptors.
Effect Of Lactobacillus Supplementation With and Without Arginine on Liver Damage and Bacterial Translocation in An Acute Liver Injury Model in the Rat
Authors: Adawi D , Kasravi F B , Molin G , Jeppsson B
Published: August 2004

In acute liver failure following hepatitis, toxic insults, or after major liver surgery, there is an increased bacterial translocation from the gut. This may explain some of the infectious complications seen in these conditions. To elucidate mechanisms and find possible preventive measures, we investigated the effect of rectal administration of arginine and probiotic bacteria (Lactobacillus spp.) on bacterial translocation and the extent of liver failure. Sprague–Dawley rats were used and five different Lactobacillus strains (Lb.) reuteri R2LC, Lb. rhamnosus DSM 6594 (= strain 271), Lb. plantarum DSM 9843 (= strain 299v), Lb. fermentum 8704:3 (= strain 245), and Lb. reuteri (= strain 108) were administered rectally once daily for 8 days with and without 2% arginine. Acute liver injury (ALI) was induced on the eighth day by intraperitoneal injection of D–galactosamine (1.1 g/kg body weight), and samples were collected after 24 and 48 hours. Bacterial translocation was evaluated by bacterial culture from portal and arterial blood, mesenteric lymph nodes, and liver tissue. Liver enzymes and bilirubin were evaluated in the serum. The bacterial load in the cecum and colon was determined and the liver histopathological changes were studied. There was no mortality at any time. The liver enzymes and bilirubin decreased in some of the groups supplemented with lactobacilli with and without arginine compared with the ALI control group. The incidence of bacterial translocation and the number of the translocated bacteria decreased significantly in some of the supplemented groups. Lb. plantarum + arginine administration significantly reduced the level of the released liver enzymes, hepatocellular necrosis and inflammatory cell infiltration, bacterial translocation, and the number of Enterobacteriaceae in the cecum and colon. Rectal administration of different Lactobacillus strains with and without arginine in an ALI model significantly modulates the extent of the liver failure and reduces bacterial translocation. Lb. plantarum DSM 9843 (= strain 299v) with or without arginine seemed superior to the other Lactobacillus strains. The beneficial effect of arginine administration alone indicates a possible role of nitric oxide and polyamines in this process, and the lactobacilli may execute their action via the same mechanisms or via bacterial antagonism and/or enhancement of systemic and intestinal mucosal immunity.
A Prognostic Model for the Outcome of Liver Transplantation in Patients With Cholestatic Liver Disease
Authors: Ricci P , Therneau T M , Malinchoc M , Benson J T , Petz J L , Klintmalm G B , Crippin J S , Wiesner R H , Steers J L , Rakela J , Starzl T E , Dickson E R
Published: August 2004

We studied the outcome of 436 patients with primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC) who underwent orthotopic liver transplant (OLT) at three major liver transplant centers. Univariate predictors of outcome included age, Karnofsky score, Child's class, Mayo risk score, United Network for Organ Sharing (UNOS) status, nutritional status, serum albumin, serum bilirubin, international normalized ratio, and the presence of ascites, encephalopathy, renal failure (serum creatinine > 2 mg/dL), and edema refractory to diuretics. Using these predictors, we developed a four variable mathematical prognostic model to help the liver transplant physician predict the following: (1) the amount of intraoperative blood loss; (2) the number of days in the intensive care unit (ICU); and (3) severe complications after surgery. The model uses age, renal failure, Child's class, and United Network for Organ Sharing status. This study is the first to model the outcome of liver transplant in patients with a specific etiology of chronic liver disease (PBC or PSC). The model may be used to help select patients for OLT and to plan the timing of their transplantation.
Virus–Induced Anti–Asialoglycoprotein Receptor Autoimmunity in Experimental Hepadnaviral Hepatitis
Authors: Diao J , Michalak T I
Published: August 2004

The relationship between hepatitis virus invasion and emergence of liver–specific autoantibodies against asialoglycoprotein receptor (anti– ASGPR) and the occurrence patterns, prognostic value, and specificity of these autoantibodies toward polypeptides of host ASGPR were investigated in experimental viral hepatitis in the woodchuck system. Sequential sera (n = 231) obtained before and after inoculation with woodchuck hepatitis virus (WHV) from animals which resolved acute infection (n = 7) or developed chronic hepatitis (n = 6) were tested for anti–ASGPR using radio and enzyme–immunodetection assays. In addition, the outcome of WHV hepatitis was analyzed in 30 other woodchucks whose preinoculation sera were tested for anti–ASGPR. The receptor subunit specificity of virus–induced anti–ASGPR was determined by Western blotting and compared with that of anti–ASGPR raised in woodchucks challenged with a heterologous (rabbit) receptor. The results revealed that WHV infection triggered anti–ASGPR in all except one of the initially autoantibody nonreactive animals (eight of nine; 89.9%). Once induced, anti–ASGPR were detectable throughout the entire follow–up independent of histological severity of liver damage or the outcome of hepatitis. In healthy WHV–naive woodchucks, anti–ASGPR occurred at low titers in approximately one third of the animals. Importantly, woodchucks reactive for anti–ASGPR before WHV inoculation developed chronic hepatitis with a significantly greater frequency (55.5%) than those autoantibody negative (15.6%; P < .05). In contrast to anti–ASGPR elicited by immunization with a heterologous receptor, which initially recognized only the ASGPR 40–kd polypeptide, anti–ASGPR emerging after virus invasion reacted with both the ASGPR 40– and 47–kd subunits from the moment of their appearance. This study provides the first direct evidence that hepatitis virus in the natural host triggers autoantibodies against a unique hepatocyte antigen and shows that anti– ASGPR autoimmunity existing before virus infection is associated with a high rate of progression to chronic disease in experimental hepadnaviral hepatitis.
The Incidence and Risk Factors of Community–Acquired Hepatitis C in A Cohort of Italian Blood Donors
Authors: Prati D , Capelli C , Silvani C , De Mattei C , Bosoni P , Pappalettera M , Mozzi F , Colombo M , Zanella A , Sirchia G
Published: August 2004

To assess the incidence and source of community–acquired hepatitis C virus (HCV) infection among subjects at low risk for blood–borne diseases, we prospectively studied a cohort of 16,515 repeat blood donors over a mean follow–up time of 36 months. Second– and third– generation methods were used for hepatitis C virus antibody (anti–HCV) testing. HCV RNA was determined in the serum of anti–HCV–positive donors by reverse–transcription polymerase chain reaction. Liver biopsy was performed in the viremic subjects. Risk factors for HCV infection were identified by a psychosocial questionnaire in the whole cohort. During follow–up, 5 donors became infected with HCV. The incidence was 1 per 10,000 person–years (95% confidence interval, 0.3–2.4 per 10,000). During the 6 months before seroconversion, four subjects (80%) underwent medical or surgical percutaneous procedures, compared with 26.5% in the entire donor cohort (difference between frequencies, 53.5%; CI: 18.9–89.1). One seroconverting donor had sexual intercourse with an infected subject. Only 1 infected donor developed clinically evident acute hepatitis. HCV RNA remained detectable in 4 of 5 subjects for 8 to 36 months after seroconversion, and liver biopsy showed chronic hepatitis in all cases. Thus, new cases of hepatitis C occur among individuals without a history of known risk factors, some of which may be caused by nosocomial exposure.
Analysis of Histopathological Manifestations of Chronic Hepatitis C Virus Infection With Respect to Virus Genotype
Authors: Mihm S , Fayyazi A , Hartmann H , Ramadori G
Published: August 2004

Hepatitis C virus (HCV) causes acute and often chronic hepatitis. On the basis of variations in nucleotide sequence, at least six genotypes and several subtypes have been identified. Histopathologically, chronic HCV infection is characterized by relatively mild hepatic inflammatory activity and a low degree of fibrosis, but hepatic lesions might be accompanied by bile duct damage, intraportal lymphoid aggregates, steatosis, or a combination of these manifestations. The histopathological lesions thus appear quite heterogeneous. To address the question of whether distinct histopathological manifestations are related to particular genotypes of HCV, 90 patients with chronic HCV infection were analyzed regarding histopathological features, biochemical liver parameters, demographic data, and virus genotype. The results revealed a significantly higher prevalence of both steatosis and bile duct lesions among patients infected by HCV type 3a compared to patients infected by types 1a or 1b. Furthermore, the data suggest interrelationships between virus genotype, patient's age, and a history of intravenous drug abuse. However, none of the histopathological manifestations were found to be related to a history of drug abuse. The data further corroborate the relationship of HCV type 1b infection to age, duration of disease, and the degree of fibrosis, respectively. Irrespective of HCV genotype, elevated serum ALT activity was shown to be associated with pronounced inflammatory activity or pronounced steatosis as well. Thus, the current data support the hypothesis that distinct genotypes of HCV appear to be associated with distinct manifestations of disease.
Analysis of Genotypes and Amino Acid Residues 2209 to 2248 of the Ns5a Region of Hepatitis C Virus in Relation to the Response to Interferon–β Therapy
Authors: Kurosaki M , Enomoto N , Murakami T , Sakuma I , Asahina Y , Yamamoto C , Ikeda T , Tozuka S , Izumi N , Marumo F , Sato C
Published: August 2004

In chronic hepatitis C virus (HCV) infection, genotypes other than genotype 1b of HCV (HCV–1b) and low serum HCV–RNA levels are known to be associated with favorable outcome of interferon alfa (IFN–α) therapy. In addition, we recently reported a close correlation between the number of mutations in amino acid sequences 2209 to 2248 of the nonstructual protein 5A gene (NS5A2209–2248) of HCV–1b and the response to IFN–α. In the present study, we analyzed these viral factors in relation to the efficacy to IFN–β, another type I IFN. The pretreatment sera of 40 patients treated with IFN–β intravenously at 6 MU daily for 42 days were studied. HCV genotypes, serum HCV–RNA levels, and the amino acid sequence of NS5A2209–2248 in HCV–1b were determined. A sustained complete response to IFN therapy occurred in none of the ten patients with the wild–type HCV–1b who had an NS5A2209–2248 sequence identical to the prototype HCV–1b and in none of the six patients with the intermediate–type HCV–1b that had 1 mutation. In contrast, complete responses occurred in the following: 4 of 6 patients with the mutant–type HCV–1b that had five to ten mutations; 6 of 13 patients with genotype 2a of HCV (HCV–2a); and 2 of 5 patients with genotype 2b of HCV (HCV–2b). Among patients with the mutant–type HCV–1b or genotype 2 of HCV (HCV–2) the rate of complete response was significantly higher (12 of 24 vs. 0 of 16 patients, P < .001) and HCV–RNA levels were significantly lower (4.5 [4.0–6.5] vs. 6 [4.5–6.5] log copies/mL, median [range]; P < .001) compared with patients with the wild–or the intermediate–type HCV–1b. Patients with the mutant–type HCV–1b or HCV–2 whose HCV–RNA levels were lower than 6 log copies/mL had a complete response rate of 75% (12 of 16 patients) in contrast to 0% (0 of 24 patients) of the others (P < .001). These results indicate that the mutant–type HCV–1b or HCV–2 are sensitive to IFN–β as well as IFN–α. In conclusion, the determination of HCV genotypes, NS5A2209–2248 of HCV–1b and serum HCV–RNA levels may facilitate the selection of patients with a high likelihood of response to IFN–β.
Ironic Insult Added to Copper Injury
Authors: Schilsky M L
Published: August 2004

Several clinical studies have suggested that excess hepatic iron accumulation is a progressive factor in some liver diseases including chronic viral hepatitis and hemochromatosis. However, it is not known whether iron–induced hepatotoxicity may be directly involved in hepatitis, cirrhosis, and liver cancer. The Long–Evans Cinnamon (LEC) rat, which accumulates excess copper in the liver as in patients with Wilson's disease, is of a mutant strain displaying spontaneous hemolysis, hepatitis, and liver cancer. We found previously that LEC rats harbored an additional abnormality: accumulation of as much iron as copper in the liver. In the present study, we compared the occurrence of hepatitis and liver cancer in LEC rats fed an iron–deficient diet (ID) with those in rats fed a regular diet (RD). The RD group showed rapid increments of hepatic iron concentrations as the result of hemolysis, characteristics of fulminant hepatitis showing apoptosis, and a 53% mortality rate. However, no rats in the ID group died of fulminant hepatitis. Hepatic iron, especially “free” iron concentration and the extent of hepatic fibrosis in the ID group were far less than those of the RD group. At week 65, all rats in the RD group developed liver cancer, whereas none did in the ID group. These results suggest that the accumulation of iron, possibly by virtue of synergistic radical formation with copper, plays an essential role in the development of fulminant hepatitis, hepatic fibrosis, and subsequent hepatocarcinogenesis in LEC rats.
Nucleation of calcium phosphate by surface‐bound extracellular matrix
Authors: Pham Minh Tan , Maitz Manfred Franz , Reuther Helfried , Muecklich Arndt , Prokert Friedrich , Steiner Gerald
Published: August 2004

The native extracellular matrix (ECM) laid down on silicon and titanium surfaces by osteoblast‐like SAOS‐2 cells was exposed by selective removal of cells. This type of material surface ECM‐Si, ECM‐Ti was shown to promote the nucleation of calcium phosphate from a simulated body fluid (SBF). Microscopic and spectroscopic results revealed the effect was associated with a collagen fiber‐free extracellular matrix. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 16–24, 2004
Nickel‐Mediated Surface Grafting From Polymerization of α‐Amino Acid‐N‐Carboxyanhydrides
Authors: Witte Peter , Menzel Henning
Published: August 2004

Summary: The feasibility of a living grafting from polymerization of α‐amino acid‐N‐carboxyanhydrides (NCA) from a surface using nickel initiators was shown. The polymerization has been carried out on commercially available polystyrene resins as spherical substrates in two different ways. Firstly L‐glutamic acid was bound to the surface as γ‐ester via a UV‐labile linker and transferred into the NCA by treatment with triphosgene. The grafting from polymerization was then carried out as a “block copolymerization” by reaction of the surface bound NCA with an excess of the Ni amido‐amidate complex initiator and subsequent addition of free NCA to grow the polymer chain. By this procedure polymer was formed at the surface and can be isolated after photolysis of the linker. The characterization of the polymer by size exclusion chromatography indicates a living polymerization at the surface. The second approach employs N‐alloc‐amides at the surface to prepare an initiating Ni amido‐amidate complex directly at the surface. It can be shown that the latter approach is much more straightforward and gives smaller quantities of non‐tethered polypeptide.

Surface bound polypeptides were obtained by ring opening polymerization of α‐amino acid‐N‐carboxyanhydrides initiated by nickel amido‐amidate complexes installed at surfaces of commercially available polystyrene resins.

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Surface bound polypeptides were obtained by ring opening polymerization of α‐amino acid‐N‐carboxyanhydrides initiated by nickel amido‐amidate complexes installed at surfaces of commercially available polystyrene resins.
Xanthate‐Mediated Controlled/Living Free‐Radical Polymerization under 60Co γ‐Ray Irradiation: Structure Effect of O‐Group
Authors: Hua Daoben , Xiao Junpeng , Bai Ruke , Lu Weiqi , Pan Caiyuan
Published: August 2004

Summary: The free‐radical polymerizations of vinyl monomers have been studied under 60Co γ‐ray irradiation in the presence of S‐benzyl O‐ethyl dithiocarbonate (X1), S‐benzyl O‐phenyl dithiocarbonate (X2), S‐benzyl O‐2‐naphthyl dithiocarbonate (X3), S‐benzyl O‐(4‐methoxyphenyl) dithiocarbonate (X4), and methyl 4‐{[(benzylthio)carbonothioyl]oxy}benzoate (X5), respectively. The results indicate that the polymerizations of methyl acrylate (MA) reveal good living characteristics in the presence of X2, X3, X4, and X5 with O‐aryl groups, which play an important role in polymerization behavior; large aryl groups lead to slow polymerization. In contrast, the polymerizations with X1 couldn't be controlled and the obtained polymers had a broad‐molecular‐weight distribution or were even cross‐linked. In addition, it was observed that the polymerization of styrene with X2 was a controlled process though it was very slow, and the uncontrolled polymerization of methyl methacrylate (MMA) occurred under γ‐ray irradiation. To the best of our knowledge, this is the first report of xanthates being used as control agents in controlled/living free radical polymerization under γ‐ray irradiation.

The structures of the xanthates used here.

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The structures of the xanthates used here.
Synthetic Uniform Polymers and Their Use for Understanding Fundamental Problems in Polymer Chemistry
Authors: Hatada Koichi , Kitayama Tatsuki , Ute Koichi , Nishiura Takafumi
Published: August 2004

Summary: A uniform polymer is a polymer composed of molecules that are uniform with respect to molecular weight and constitution. Besides natural uniform polymers such as nucleic acids and polypeptide, synthetic uniform polymers have been obtained by a variety of approaches. In particular, a combination of living polymerization and supercritical fluid chromatography (SFC) separation is one of the promising ways for the preparation of uniform polymers. End‐functionalized uniform polymers enabled us to prepare uniform polymer architectures such as block, graft, comb, and star polymers. Their use for understanding the fundamental problems in polymer chemistry is discussed; topics include crystallization of polymers, chain conformation in solution, and association of stereoregular polymers in solution.

SFC traces of isotactic PMMA containing an authentic sample of the 45‐mer (a) and of the isolated uniform PMMA of 100‐mer (b).

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SFC traces of isotactic PMMA containing an authentic sample of the 45‐mer (a) and of the isolated uniform PMMA of 100‐mer (b).
Silica/Poly(1,5‐dioxepan‐2‐one) Hybrid Nanoparticles by “Direct” Surface‐Initiated Polymerization
Authors: Yoon Kuk Ro , Lee Yong‐Won , Lee Jungkyu K. , Choi Insung S.
Published: August 2004

Summary: Biodegradable poly(1,5‐dioxepan‐2‐one) (PDXO) was grown directly from SiOH groups of a silica nanoparticle by surface‐initiated, ring‐opening polymerization (SI‐ROP) of 1,5‐dioxepan‐2‐one (DXO). The direct SI‐ROP of DXO was achieved by heating a mixture of Sn(Oct)2, DXO, and the silica nanoparticles (316 nm in diameter) in anhydrous toluene. The resulting silica/PDXO hybrid nanoparticles were characterized by means of 1H NMR spectroscopy, IR spectroscopy, thermogravimetric analysis, and field‐emission scanning electron microscopy.

The procedure for the surface‐initiated, ring‐opening polymerization of 1,5‐dioxepan‐2‐one on silica nanoparticles reported here.

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The procedure for the surface‐initiated, ring‐opening polymerization of 1,5‐dioxepan‐2‐one on silica nanoparticles reported here.
Machado–Joseph shoe
Authors: Liu Chin San , Hsieh Mingli , Chen Yi Yun , Lo Man Chi
Published: August 2004

Machado–Joseph shoe (MJS), defined as a shoe/slipper with a deep hallux imprint at its base, and hyperostosis/osteoma toe were two early ataxic signs in 17 of 31 patients (55%) and 24 of 31 patients (77%) with Machado–Joseph disease (MJD), respectively. The MJS plus hyperostosis/osteoma toes may be helpful in the diagnosis of MJD in a patient during early truncal ataxia. © 2004 Movement Disorder Society
1H, 13C and 15N NMR spectra of ciprofloxacin
Authors: Ziȩba Andrzej , Maślankiewicz Andrzej , Sitkowski Jerzy
Published: August 2004

1H NMR assignment, including the values of δH and J(H,H) for the cyclopropane moiety, and 13C NMR and 15N NMR spectral data for ciprofloxacin are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Gene expression profiling of colorectal cancer and metastases divides tumours according to their clinicopathological stage
Authors: Koehler Astrid , Bataille Frauke , Schmid Cornelia , Ruemmele Petra , Waldeck Annette , Blaszyk Hagen , Hartmann Arndt , Hofstaedter Ferdinand , Dietmaier Wolfgang
Published: August 2004

Gene expression profiling of matched colorectal carcinomas and metastases could reveal key molecular events involved in tumour progression and metastasis. Expression profiles have been created from 25 colorectal carcinomas (CRCs, pT1–4), corresponding normal colonic mucosa, and 14 liver metastases using cDNA arrays containing 1176 cancer‐related genes (Clontech). Hierarchical clustering clearly distinguished carcinomas from non‐cancerous tissues, separated tumours into high‐stage (pT4 and extensive lymph node or distant metastases) and low‐stage (≤pT3) groups, and correlated with the histopathological classification in 87% (33/38 cases). Most primary tumours and matched liver metastases clustered on terminal branches of the dendrogram. Statistical analysis (Mann–Whitney U‐test) revealed 40 tumour‐specific genes (29 up‐regulated, 11 down‐regulated) which allowed identification of malignant tissue samples by cluster analysis. A specific expression signature in matching metastases was not found, but a set of 23 classifier genes with statistically significant expression patterns in high‐ and low‐stage tumours was identified. These genes may represent important targets in colorectal carcinogenesis and might provide useful clinicopathological tools in the management of colorectal cancer. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Segmental and secondary dynamics in hydrogen‐bonded poly(4‐vinylphenol)/poly(methyl methacrylate) blends
Authors: Zhang Shihai , Runt James
Published: August 2004

Broadband dielectric spectroscopy was used to study the segmental (α) and secondary (β) relaxations in hydrogen‐bonded poly(4‐vinylphenol)/poly(methyl methacrylate) (PVPh/PMMA) blends with PVPh concentrations of 20–80% and at temperatures from −30 to approximately glass‐transition temperature (Tg) + 80 °C. Miscible blends were obtained by solution casting from methyl ethyl ketone solution, as confirmed by single differential scanning calorimetry Tg and single segmental relaxation process for each blend. The β relaxation of PMMA maintains similar characteristics in blends with PVPh, compared with neat PMMA. Its relaxation time and activation energy are nearly the same in all blends. Furthermore, the dielectric relaxation strength of PMMA β process in the blends is proportional to the concentration of PMMA, suggesting that blending and intermolecular hydrogen bonding do not modify the local intramolecular motion. The α process, however, represents the segmental motions of both components and becomes slower with increasing PVPh concentration because of the higher Tg. This leads to well‐defined α and β relaxations in the blends above the corresponding Tg, which cannot be reliably resolved in neat PMMA without ambiguous curve deconvolution. The PMMA β process still follows an Arrhenius temperature dependence above Tg, but with an activation energy larger than that observed below Tg because of increased relaxation amplitude. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3405–3415, 2004
Structure of polypropylene crystallized in confined nanolayers
Authors: Jin Y. , Rogunova M. , Hiltner A. , Baer E. , Nowacki R. , Galeski A. , Piorkowska E.
Published: August 2004

Films with a thousand alternating layers of isotactic polypropylene (PP) and polystyrene (PS) were prepared by layer‐multiplying coextrusion. The crystal structure of extremely thin PP layers confined between PS layers was studied by optical light microscopy (OM), atomic force microscopy (AFM), differential scanning calorimetry (DSC), small‐angle X‐ray scattering (SAXS), and wide‐angle X‐ray scattering (WAXS). Changes in structure were observed as the PP layer thickness decreased to the nanoscale. The thin PP discoids were largely composed of edge‐on lamellae with (040) planes lying flat on the interface. In layers 65 and 10‐nm thick, compressed d‐spacings in the directions perpendicular to the chains and loss of registry along the chain axis were suggestive of smectic packing of conformationally distorted chains. Even so, crystalline lamellae were distinguishable in the AFM images. In addition to the crystal population with (040) planes parallel to the interface, the WAXS from layers 65‐nm thick revealed another crystal fraction with (110) planes parallel to the interface and (040) planes perpendicular to the interface. This fraction was more evident in layers 10‐nm thick, where it accounted for approximately 10–20% of the crystallinity. Decreasing layer thickness resulted in a change of the crystal growth plane from the usual (110) to the more rare (010). The new crystal structure possibly served to fill‐in the radial structure of the dendritic discoids when a limitation to the thickness of the layer left only a little space for secondary nucleation of the crosshatched lamella. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3380–3396, 2004
The β‐crystalline form of isotactic polypropylene in blends of isotactic polypropylene and polyamide‐6/clay nanocomposites
Authors: Feng Meng , Gong Fangling , Zhao Chungui , Chen Guangming , Zhang Shimin , Yang Mingshu , Han Charles C.
Published: August 2004

Blends of isotactic polypropylene and polyamide‐6/clay nanocomposites (iPP/NPA6) were prepared with an internal batch mixer. A high content of the β‐crystalline form of isotactic polypropylene (β‐iPP) was observed in the injection‐molded samples of the iPP/NPA6 blends, whereas the content of β‐iPP in the iPP/PA6 blends and the iPP/clay composite was low and similar to that of neat iPP. Quiescent melt crystallization was studied by means of wide‐angle X‐ray diffraction, differential scanning calorimetry, and polarized optical microscopy. We found that the significant β‐iPP is not formed during quiescent melt crystallization regardless of whether the sample used was the iPP/NPA6 blend or an NPA6 fiber/iPP composite. Further characterization of the injection‐molded iPP/NPA6 revealed a shear‐induced skin–core distribution of β‐iPP and the formation of β‐iPP in the iPP/NPA6 blends is related to the shear flow field during cavity‐filling. In the presence of clay, the deformation ability of the NPA6 domain is decreased, as evidenced by rheological and morphological studies. It is reasonable that the enhanced relative shear, caused by low deformability of the NPA6 domain in the iPP matrix, is responsible for β‐iPP formation in the iPP/NPA6 blends. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3428–3438, 2004
Modeling the swelling pressure of degrading hydroxyethylmethacrylate‐grafted dextran hydrogels
Authors: Amsden B. G. , Stubbe B. G. , Horkay F. , De Smedt S. C. , Demeester J.
Published: August 2004

Degrading hydroxyethylmethacrylate‐grafted dextran (dex‐HEMA) hydrogels generate a relatively sudden increase in osmotic pressure upon degradation into dextran solutions. This phenomenon is currently being examined as a possible means of developing a pulsatile drug‐delivery system. Here a mathematical model based on scaling concepts is presented to describe this sudden increase in swelling pressure and to provide a framework for the rational design of pulsatile delivery systems based on this phenomena. The model provides a good fit to the swelling pressures measured for dex‐HEMA gel/free dextran mixtures that simulate degrading dex‐HEMA gels. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3397–3404, 2004
Psychological and educational factors: Better predictors of work status than FEV1 in adults with cystic fibrosis
Authors: Burker Eileen J. , Sedway Jan , Carone Stacia
Published: August 2004

Now that more individuals with cystic fibrosis (CF) are living into adulthood, vocational attainment is an increasingly important consideration. Work is a key factor in quality of life. The purpose of the present paper was to evaluate the factors that are associated with work status in 183 adults with CF. Approximately half of the participants were working at the time of evaluation, an impressive figure given that the mean forced expired volume in 1 sec (FEV1) was 31.9%. The average number of hours worked was 32.7 hr/week. The majority of individuals were employed in professional, technical, or managerial occupations (accounting, teaching, law, or social work). A third were employed in clerical and sales occupations, and the remaining individuals were employed in a wide range of other occupations (hotel manager, undercover shopper, artist, or dental technician). Interestingly, FEV1 and age did not differentiate between subjects who were working and those who were not. Individuals who were working had significantly lower depression scores and a higher educational level than those who were not working. Future research is needed to determine whether it is the increased socialization and the resulting social support that may come from a work environment, or a reduction in financial stress because of better income and health benefits that helps to explain this difference. Alternatively, work may serve as a distraction from the symptoms of CF. It is likely that those with higher educational levels had more professional jobs that were more easily modified as health declined. Future research needs to assess how career choices are made, and what factors into a patient's decision to keep working. © 2004 Wiley‐Liss, Inc.
Comparative evaluation of eight docking tools for docking and virtual screening accuracy
Authors: Kellenberger Esther , Rodrigo Jordi , Muller Pascal , Rognan Didier
Published: August 2004

Eight docking programs (DOCK, FLEXX, FRED, GLIDE, GOLD, SLIDE, SURFLEX, and QXP) that can be used for either single‐ligand docking or database screening have been compared for their propensity to recover the X‐ray pose of 100 small‐molecular‐weight ligands, and for their capacity to discriminate known inhibitors of an enzyme (thymidine kinase) from randomly chosen “drug‐like” molecules. Interestingly, both properties are found to be correlated, since the tools showing the best docking accuracy (GLIDE, GOLD, and SURFLEX) are also the most successful in ranking known inhibitors in a virtual screening experiment. Moreover, the current study pinpoints some physicochemical descriptors of either the ligand or its cognate protein‐binding site that generally lead to docking/scoring inaccuracies. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Three‐dimensional model of a substrate‐bound SARS chymotrypsin‐like cysteine proteinase predicted by multiple molecular dynamics simulations: Catalytic efficiency regulated by substrate binding
Authors: Pang Yuan‐Ping
Published: August 2004

Severe acute respiratory syndrome (SARS) is a contagious and deadly disease caused by a new coronavirus. The protein sequence of the chymotrypsin‐like cysteine proteinase (CCP) responsible for SARS viral replication has been identified as a target for developing anti‐SARS drugs. Here, I report the ATVRLQp1Ap1'‐bound CCP 3D model predicted by 420 different molecular dynamics simulations (2.0 ns for each simulation with a 1.0‐fs time step). This theoretical model was released at the Protein Data Bank (PDB; code: 1P76) before the release of the first X‐ray structure of CCP (PDB code: 1Q2W). In contrast to the catalytic dyad observed in X‐ray structures of CCP and other coronavirus cysteine proteinases, a catalytic triad comprising Asp187, His41, and Cys145 is found in the theoretical model of the substrate‐bound CCP. The simulations of the CCP complex suggest that substrate binding leads to the displacement of a water molecule entrapped by Asp187 and His41, thus converting the dyad to a more efficient catalytic triad. The CCP complex structure has an expanded active‐site pocket that is useful for anti‐SARS drug design. In addition, this work demonstrates that multiple molecular dynamics simulations are effective in correcting errors that result from low‐sequence‐identity homology modeling. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Theoretical study of the ground‐state gas‐phase unimolecular decomposition channels of propynoic acid
Authors: Ndip Edmund Moses N. , Shukla Manoj K. , Leszczynski Jerzy , Redington Richard L.
Published: August 2004

Theoretical studies have been carried out to elucidate the ground‐state unimolecular decomposition channels for propynoic acid (PA) in the gas phase. In this paper we present details of mechanisms for the decarboxylation and decarbonylation channels of PA. The transformations of PA result in the formation of carbon dioxide and acetylene from the decarboxylation channel while carbon monoxide and hydroxyacetylene, ultimately the ketene, are formed from the decarbonylation pathway. Equilibrium structures and the principal transition states (TSs) for each pathway have been identified and characterized. The Gaussian 98 suite of programs and MOLDEN were used for computation and visualization. All computations of equilibrium and TS structures relevant to the two competing unimolecular decomposition channels (decarboxylation and decarbonylation) were performed with second‐order Møller–Plesset (MP2) and Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar (B3LYP) levels using the 6‐31G(d,p), 6‐311++G (d, p) and Dunning's correlation‐consistent polarized valence basis set (aug‐cc‐pVDZ). The geometries were fully optimized and characterized as minima (0 imaginary frequencies) or first‐order saddle points (1 imaginary frequency) by harmonic vibrational analysis at the MP2/6‐311++G(d,p) and B3LYP/6‐311++G(d,p) levels. All the calculations indicate that the lowest energy decomposition pathway for PA is decarboxylation. Decarboxylation of PA occurs most easily through a three‐step mechanism: conversion of s‐cis‐HCCCO2H to s‐trans‐HCCCO2H, followed by a 1, 3‐hydrogen migration of hydroxyl hydrogen, resulting in a four‐center TS that decays easily to acetylene and carbon dioxide, with an activation barrier of 61.3–79.9 kcal/mol (average 65.67 kcal/mol). Decarbonylation, leading to hydroxyacetylene (and subsequently the ketene) and carbon monoxide, occurs easily via a direct (one‐step) three‐center TS. The direct (one‐step) elimination of carbon monoxide from propynoic acid has a calculated average activation barrier of 67.9–81.7 kcal/mol (average, 74.1 kcal/mol). The decarboxylation pathway is shown to occur with a maximum exothermicity of 28 kcal/mol. On the contrary, the decarbonylation of PA is predicted to occur with an overall endothermicity of ≈29.2 kcal/mol for formation of hydroxyacetylene and carbon monoxide and an average exothermicity of −7.69 kcal/mol for formation of the ketene and carbon monoxide. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Quantitative determination of trace concentrations of tetracycline and sulfonamide antibiotics in surface water using solid‐phase extraction and liquid chromatography/ion trap tandem mass spectrometry
Authors: Yang Shinwoo , Cha Jongmun , Carlson Kenneth
Published: August 2004

The occurrence of human and veterinary pharmaceutical compounds in surface waters (e.g. streams, lakes and reservoirs) is an important emerging environmental issue. There is a need for robust, sensitive and reliable analytical methods for measuring these compounds in a variety of natural water and wastewater matrices. This paper describes a method for the determination of seven tetracycline (TC) and six sulfonamide (SA) compounds in pristine and wastewater‐influenced surface water using solid‐phase extraction, and LCQ Duo ion trap liquid chromatography/tandem mass spectrometry (LC/MS/MS) with positive electrospray ionization (ESI(+)) and selected reaction monitoring (SRM). The seven TCs and six SAs analyzed using this method include oxytetracycline (OTC), chlortetracycline (CTC), tetracycline (TC), democlocycline (DMC), doxycycline (DXC), meclocycline (MCC), minocycline (MNC), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMT), sulfachloropyridazine (SCP), sulfamethoxazole (SMX), and sulfadimethoxane (SDM). This study discusses the effects of flow rate, LC column diameter and LC column temperature on UV and/or mass peak quality of the different analytes. Several product ions for MS/MS detection have been identified and compared for ion trap and triple quadrupole LC/MS/MS instruments. Statistical analysis for determination of the method detection limit (MDL), accuracy and precision of the method is described. Matrix effects are evaluated in deionized, pristine and wastewater‐influenced river water. The method is applied to evaluate the occurrence of these compounds in a small watershed in northern Colorado. Copyright © 2004 John Wiley & Sons, Ltd.
Latent and lytic Epstein‐Barr virus replication strategies
Authors: Tsurumi Tatsuya , Fujita Masatoshi , Kudoh Ayumi
Published: August 2004

The Epstein‐Barr virus (EBV) can choose between two alternative lifestyles; latent or lytic replication. In the latent state, the EBV genomic DNA, which exists as a closed circular plasmid, appears to behave just like host chromosomal DNA and it has been demonstrated recently that replication of OriP‐containing plasmids is indeed dependent on the chromosomal initiation factors, ORC2 and Cdt1. On the other hand, in the viral productive cycle, the EBV genome is amplified 100‐ to 1000‐fold by the viral replication machinery. EBV productive DNA replication occurs at discrete sites in nuclei, called replication compartments and the lytic programme arrests cell cycle progression and changes the cellular environment greatly. It has been revealed recently that the EBV lytic programme promotes an S‐phase like cellular condition, which most favours viral lytic replication. This review describes recent advances regarding the molecular basis of EBV DNA replication during latent and lytic infections and then refers to cellular circumstances after induction of the lytic replication of EBV. Based on the molecular mechanism for the EBV lifestyle, purposeful induction of the lytic form of EBV infection is now advocated as one of the strategies for specific destruction of Epstein‐Barr virus (EBV)‐associated malignancies where the virus is latently infected. Copyright © 2004 John Wiley & Sons, Ltd.
Should the sociology of science be rated X?
Authors: Allchin Douglas
Published: August 2004

Stephen Brush once asked, “Should the history of science be rated ‘X’” Well, times have changed. Now controversy reigns over the role of sociology in the science classroom. Here, I profile several dimensions of the sociology of science and survey recent efforts by philosophers to address its most radical claims. In respecting the opposing poles of this contentious debate, I contend that it is possible to chart a path between the Scylla of scientism and the Charybdis of relativism. Most notably, educators must differentiate between the normative and descriptive elements of the ‘nature of science’—and teach both. Further, they must go beyond the rhetoric of tentativeness and fallibility in science by describing just when and how individual scientists and/or a scientific community can err—and how they identify and remedy their errors. © 2004 Wiley Periodicals, Inc. Sci Ed 88:934–946, 2004
The hedonic response to cigarette smoking is proportional to dopamine release in the human striatum as measured by positron emission tomography and [11C]raclopride
Authors: Barrett Sean P. , Boileau Isabelle , Okker Johanna , Pihl Robert O. , Dagher Alain
Published: August 2004

Positron emission tomography and [11C]raclopride were used to assess the dopaminergic response to cigarette smoking in ten smokers. Nicotine‐deprived smokers were scanned twice on separate days. In one condition, participants smoked their usual brand of cigarettes while in the scanner and in the other condition they remained nicotine abstinent. On each day, subjects monitored the hedonic properties of their experience as well as their levels of craving. Initial analyses revealed no significant differences between the conditions in [11C]raclopride binding potential (BP) in the caudate, putamen, or ventral striatum. Because previous research suggested that drug‐induced dopamine transmission is related to levels of craving and/or hedonic drug effects, the relationship between these variables and [11C]raclopride BP was examined. Craving levels were reduced by smoking but were not systematically related to BP change. However, the hedonic response to smoking was correlated with BP reduction in the caudate (P < 0.001) and posterior putamen (P < 0.05) but not in the ventral striatum. Post hoc analyses revealed that only five of the ten smokers reported mood‐elevating effects in response to the smoking procedure. In these subjects, smoking was associated with decreased [11C]raclopride BP in the caudate. On the other hand, among subjects that reported a diminished mood response to smoking there was an increase in BP in the caudate and putamen. These results suggest that pleasurable drug experiences are associated with increased dopamine transmission in the dorsal striatum while unpleasant experiences may be related to decreased dopamine release in this region. Synapse 54:65–71, 2004. © 2004 Wiley‐Liss, Inc.
Herpes zoster ophthalmicus leading to middle cerebral arteryinfarction: A case report
Authors: Kalita J. , Das M. , Misra U.K.
Published: August 2004

Herpes zoster vasculitis is a rare but important complication. We report a 27-year-old man who, after three months of herpes zoster ophthalmicus, developed left-sided hemiplegia with grade-zero power and cortical sensory loss. A CT scan showed an infarction in the right middle cerebral artery. An MR angiogram showed occlusion of the right middle cerebral artery. The CSF was positive for herpes zoster IgM and IgG antibodies. The patient improved following acyclovir therapy and was independent for activities of daily living at his one-month followup. Large-vessel occlusion occurs in herpes zoster ophthalmicus in an immunocompetent patient and may have a good prognosis.
Pakistani adolescents’ coping with stress: effect of loss of a parent and gender of adolescents
Authors: Kausar Rukhsana , Munir Rukhsana
Published: August 2004

The present study examined the effect of parental loss and gender of adolescents on their coping with stress. Sample included those adolescents who had either of their parents died (N=40) and those having both living parents (N=40). It was hypothesized that adolescents with one parent alive would differ in their ways of coping with stress compared to those who have both living parents. It was also hypothesized that there would be gender differences in adolescents’ coping. Coping Strategies Questionnaire (CSQ, Kausar, 1996) was used to assess adolescents’ coping. Data was analysed using t‐test and multivariate analysis of variance (MANOVA). Analyses showed that avoidance‐focused coping was the most frequently used and active distractive coping was the least frequently used strategy by the adolescents. Adolescents with both living parents employed more active distractive and religious‐focused coping compared to those with one parent alive. Girls employed significantly more strategies to cope with stress compared to boys. Results also revealed interactive effect of parental loss and gender on coping strategies used by adolescents. The findings suggest that death of either of the parents and gender of the adolescent is important determinants of the ways adolescents deal with stress.
Quasi-neutral limit for a viscous capillary model of plasma
Authors: Bresch Didier , Desjardins Benoît , Ducomet Bernard
Published: August 2004

The purpose of this work is to study the quasi-neutral limit of a viscous capillary model of plasma expressed as a so-called Navier–Stokes–Poisson–Korteweg model. The existence of global weak solutions for a given Debye length

λ

is obtained in a periodic box domain

\mathrm{T}^{3}

or a strip domain

\mathrm{T}^{2} \times (0\text{,}1)

. The convergence when

λ

goes to zero to solutions to the compressible capillary Navier–Stokes equations, in the torus

\mathrm{T}^{3}

, turns out to be global in time in energy norm.

Le but de ce travail est d'étudier la limite quasi-neutre d'un modèle de plasma que l'on désignera comme le modèle de Navier–Stokes–Poisson–Korteweg. L'existence de solutions globales faibles, pour une longueur de Debye

λ

fixée, est obtenue dans un domaine périodique

\mathrm{T}^{3}

ou un domaine de type bande

\mathrm{T}^{2} \times (0\text{,}1)

. La convergence quand

λ

tend vers 0 vers les solutions des équations de Navier–Stokes capillaires compressibles, dans le tore

\mathrm{T}^{3}

, est alors globale en temps.