bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of biodegradable amphiphilic AB‐type diblock copolymers of lactide and depsipeptide with pendant reactive groups
Authors: Ouchi Tatsuro , Miyazaki Hidetake , Arimura Hidetoshi , Tasaka Fumitaka , Hamada Atsushi , Ohya Yuichi 
Published: August 2002

AbstractThe syntheses of amphiphilic AB‐type diblock copolymers composed of hydrophobic polylactide segment and hydrophilic polydepsipeptide segment with amino or carboxyl groups were performed. The protected cyclodepsipeptides cyclo[Glc‐Lys(Z)] and cyclo[Glc‐Asp(OBzl)] (where Glc is glycolic acid, Lys is lysine, Asp is aspartic acid, Z is benzyloxycarbonyl, and OBzl is benzyl) were first polymerized in tetrahydrofuran (THF) with potassium ethoxide as an initiator to obtain the corresponding protected polydepsipeptides. After the terminal hydroxyl groups of the protected polydepsipeptides were converted into the potassium alcoholates with K/naphthalene, L‐lactide was polymerized in the presence of the corresponding polymeric alcoholates as macroinitiators in THF to obtain poly[Glc‐Lys(Z)]‐block‐poly(L‐lactide) and poly[Glc‐Asp(OBzl)]‐block‐poly(L‐lactide). Subsequent deprotection of Z and OBzl groups gave the objective amphiphiles poly(Glc‐Lys)‐block‐poly(L‐lactide) and poly(Glc‐Asp)‐block‐poly(L‐lactide), respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1218–1225, 2002
Application of ketenes to well‐defined polyester synthesis. III. Living anionic polymerization of ethyl(4‐methoxyphenyl)ketene—Development of polyester having masked phenol side chain
Authors: Sudo Atsushi , Uchino Satoshi , Endo Takeshi 
Published: August 2002

AbstractA novel ketene, ethyl(4‐methoxyphenyl)ketene (EMPK), was synthesized by the dehydrochlorination of 2‐(4‐methoxyphenyl)butanoyl chloride. The anionic polymerizations of EMPK by butyllithium in tetrahydrofuran at −20 °C were carried out with a varying feed ratio to give the corresponding polyesters having predictable molecular weights and narrow molecular weight distributions, quantitatively. The selective formation of the polyester was confirmed by IR analysis, and the reductive degradation of the polymer was supported by lithium–aluminium hydride. The second feed of the monomer (after the first stage of polymerization) resulted in the formation of the polymer with the expectedly increased molecular weight and low polydispersity to strongly support the living mechanism of this polymerization. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1596–1600, 2001
Structures and thermal properties of chitosan‐modified poly(methyl methacrylate)
Authors: Don Trong‐Ming , Hsu Shih‐Chang , Chiu Wen‐Yen 
Published: August 2002

AbstractThe emulsion polymerization of methyl methacrylate in the presence of chitosan with potassium persulfate (KPS) as an initiator was examined in a previous article. The free radicals that dissociated from KPS not only initiated the polymerization but also degraded the chitosan molecules. Therefore, in addition to its role as a cationic surfactant, chitosan also participated in the polymerization reaction. When the polymerization was complete, the latex polymer consisted of poly(methyl methacrylate) (PMMA) homopolymer and chitosan–PMMA copolymer. In this article, the structures and thermal properties of latex polymers are examined. Gel permeation chromatography was used to measure the molecular weight of the PMMA homopolymer, with the copolymer composition determined by an elemental analyzer. Scanning and transmission electronic microscopes were used to measure the size of latex particles from different reaction systems. The surface charges of latex particles at several different pH values were determined by the measurement of the ζ potential. All results agreed with the reaction mechanism proposed in the previous article. Finally, the presence of rigid chitosan increased the glass‐transition temperature of the final latex polymers. Thermogravimetric analysis showed that the degradation behavior of latex polymers was similar to the unzipping mechanism of PMMA, yet the presence of chitosan units hindered the unzipping of the main chains in chitosan–PMMA copolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1646–1655, 2001
Cationic grafting of olefins from PVC: The effect of reaction conditions
Authors: Pi Zhengjie , Kennedy J. P. 
Published: August 2002

AbstractThe cationic grafting of isobutylene, styrene, α‐methylstyrene, and β‐pinene from a poly(vinyl chloride) (PVC) backbone was investigated. Grafting‐from was induced by Et2AlCl in 1,2‐dichloroethane and methylene dichloride solutions from 20 to −70 °C. The effects of temperature and proton trap [2,6‐di‐tert‐butylpyridine (DtBP)] on grafting‐from efficiency (Geff), extent of grafting, branch length (molecular weight), and number of branches per PVC molecule were determined. Reducing the temperature invariably increased the Geff and the molecular weight of polyisobutylene, polystyrene, poly(α‐methylstyrene), and poly(β‐pinene) branches attached to PVC. The magnitude of the effects was different with the various olefins and depended on the reaction conditions. The effect of DtBP was examined in the 5 × 10−4–4 × 10−3 mol/L range. By increasing the DtBP concentration the Geff increased; however, the number‐average molecular weight of the grafted branches decreased. The lengths of the grafted branches can be controlled, and Geff's close to 100% were obtained. The fact that the proton trap reduced the molecular weights of grafted branches suggests that besides proton scavenging, DtBP may also abstract protons from the growing carbenium ion site. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1675–1680, 2001
Nuclear magnetic relaxation in polyolefin resins
Authors: Doolan K. R. 
Published: August 2002

AbstractNuclear magnetic resonance (NMR) spin–lattice relaxation times (T1) in various polyethylene and polypropylene resins were measured at 20 MHz and at temperatures of 130–490 K. At each temperature and for all resins, only a single value of T1 was found, which was consistent with the occurrence of rapid spin diffusion throughout the protons attached to the polymer chains. The data were analyzed for the estimation of activation energies corresponding to molecular motion causing spin–lattice relaxation. Two well‐defined minima were found for loge(T1) plotted as a function of temperature for all of the polypropylene resins. Single very broad minima were found for all of the polyethylene samples. In contrast, the free induction decay signals from all of the resins following single radio‐frequency pulses were observed to contain a rapidly decaying component followed by a much more slowly decaying signal. These components were used to estimate the amount of rigid component present in the solid resins at room temperature. Samples of one high‐density polyethylene and one low‐density polyethylene were irradiated with γ radiation up to a 500‐kGy dose to examine the effects of crosslinking on the NMR relaxation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 572–584, 2002; DOI 10.1002/polb.10116
Rheology of polystyrene solutions around the coil overlapping concentration: A phenomenological description of stresses in simple shear flow
Authors: Osaki K. , Inoue T. , Uematsu T. , Yamashita Y. 
Published: August 2002

AbstractLinear viscoelasticity behavior is described with the sum of two terms for polystyrene solutions in tricresyl phosphate around the coil overlapping concentration (K. Osaki, T. Inoue, & T. Uematsu, J Polym Sci Part B: Polym Phys 2001, 39, 211). One is a Rouse–Zimm (RZ) term represented by the Zimm theory with arbitrarily chosen values of the hydrodynamic interaction parameter and the longest relaxation time (τRZ). The other (the L term) consists of a relaxation mode with a single relaxation time (τL > τRZ) and a high‐frequency limiting modulus proportional to the square of the concentration. In this study, we describe the viscosity (η) and first normal stress coefficient (Ψ1) in steady shear with simple formulas. The stress due to the L term is assumed to be given by a Kaye, Bernstein, Kearsley, and Zapas (K‐BKZ) equation with the damping function h(γ) = (1 + 0.2γ2)−1/2, where γ is the magnitude of shear. Contributions to η and Ψ1 from the RZ term are derived from the RZ model, in which the relaxation time in steady flow is given by τst = τ + (τRZ − τ)/(1 + 0.35τRZ γ˙) instead of τRZ. Here, γ˙ is the rate of shear, and τ is the τRZ value at the infinite dilution limit. η and Ψ1 at various concentrations for two polystyrene samples (with molecular weights of 2890 and 8420 kg mol−1) are well described with parameters derived from dynamic viscoelasticity. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1038–1045, 2002
Multiple endocrine neoplasia type 2a (MEN2a): a call for psycho‐social research
Authors: Giarelli Ellen 
Published: August 2002

AbstractThis paper summarizes what is known about the diagnosis, treatment, and follow‐care of people with the inherited disorder multiple endocrine neoplasia type 2a (MEN2a). Several databases were searched throughout the year 2000, including MEDLINE, CINAHL, CancerLit, PsychINFO, and Dissertation Abstracts International. MEN2a is a complex disease involving cancer care and control by surgery, health maintenance, and life‐long observation of gene mutation carriers. Genetic testing is the standard of care, prophylactic surgery is recommended during directive counseling, and life‐long surveillance is encouraged for people with MEN2a. A substantial body of scientific literature describes morbidity and mortality outcomes of disease treatment, and the monitoring of multiple organ systems. Research is scant concerning the psychological consequences and social impact of the MEN2a diagnosis, treatment, and follow‐up. Nearly all that is known from a psycho‐social perspective comes from data in The Netherlands. Little is known of the psychological responses to and social consequences of genetic predisposition testing, prophylactic and curative surgery, and life‐long surveillance. Psycho‐social research is essential to provide comprehensive care for patients and family members with this disorder and it is necessary to guide the development of risk management strategies for patients with this inherited cancer syndrome. Since MEN2a has been labeled a prototype for medical genetics, information on MEN2a patient experiences may be relevant to the care of individuals with other inherited cancer syndromes. Copyright © 2002 John Wiley & Sons, Ltd.
Respiratory diseases in the first year of life in children born to HIV‐1‐infected women*
Authors: Kattan Meyer , Platzker Arnold , Mellins Robert B. , Schluchter Mark D. , Chen Xin C. , Peavy Hannah , Steinbach Suzanne , Wohl Mary Ellen , Hiatt Peter , Hunter Janice , Colin Andrew A. 
Published: August 2002

AbstractOur objective was to describe the respiratory complications, clinical findings, and chest radiographic changes in the first year of life in infected and uninfected children born to HIV‐1‐infected women. We prospectively followed a cohort of 600 infants born to HIV‐1‐infected women from birth to 12 months in a multicenter study. Of these, 93 infants (15.5%) were HIV‐1‐infected, 463 were uninfected, and 44 were of unknown status prior to death or loss to follow‐up.The cumulative incidence ( ± SE) of an initial pneumonia episode at 12 months was 24.1 ± 4.7% in HIV‐1‐infected children compared to 1.4 ± 0.6% in HIV‐1‐uninfected children (P < 0.001). The rate of Pneumocystis carinii pneumonia (PCP) was 9.5 per 100 child‐years. The HIV‐1 RNA load was not higher in the group that developed pneumonia in the first year vs. those who did not. Children who developed lower respiratory tract infections or PCP had increased rates of decline of CD4 cell counts during the first 6 months of life. Lower maternal CD4 cell counts were associated with higher rates of pneumonia, and upper and lower respiratory tract infections. The rates of upper respiratory tract infection and bronchiolitis/reactive airway disease in infected children were not significantly different than in uninfected children. At 12 months, significantly more HIV‐1‐infected than uninfected children had tachypnea and chest radiographs with nodular and reticular densities. There was no relationship between cytomegalo virus infection in the first year of life and radiographic changes or occurrences of pneumonia.In conclusion, despite a low incidence of PCP, rates of pneumonia remain high in HIV‐infected children in the first year of life. The incidence of pneumonia in uninfected infants born to HIV‐1‐infected mothers is low. Chest X‐ray abnormalities and tachypnea suggest that subacute disease is present in infected infants. Further follow‐up is warranted to determine its nature. Pediatr Pulmonol. 2001; 31:267–276. © 2001 Wiley‐Liss, Inc.
Pulmonary artery occlusion from tuberculous lymphadenopathy in a child
Authors: Equi Amanda , Redington Andrew , Rosenthal Mark , Taylor G. Michael , Jaswon Mervyn , Bush Andrew 
Published: August 2002

AbstractOcclusion of the pulmonary artery is a rare complication of mediastinal tuberculosis. We report on a 10‐year‐old girl who presented with a tuberculous pericardial effusion in whom subsequent imaging showed a totally occluded right pulmonary artery from tuberculous lymphadenopathy. Diagnosis was confirmed by polymerase chain reaction from a lymph node biopsy. Failure of medical therapy necessitated surgical reconstruction of her right pulmonary artery. Postoperatively she has normal perfusion of the right lung and normal lung function. Pediatr Pulmonol. 2001; 31:311–313. © 2001 Wiley‐Liss, Inc.
Transition programs in cystic fibrosis centers: Perceptions of pediatric and adult program directors
Authors: Flume Patrick A. , Anderson Deborah L. , Hardy Kristina K. , Gray Sue 
Published: August 2002

AbstractThere is a growing population of adults with cystic fibrosis (CF) and a need for development of adult CF programs. Recommendations for transfer of patients to an adult program include a transition program. Our goal was to assess the current status of transition programs in US CF centers. In addition, we sought to determine the problems related to the transfer of patients to adult programs as perceived by CF center program directors.A survey was sent in 1998 to 110 pediatric and 44 adult program directors at CF centers approved by the Cystic Fibrosis Foundation (CFF), with a response rate of 65.5% and 72.7%, respectively: 22.2% of pediatric centers reported having a non‐CFF‐approved adult program, and 38.9% had no specific adult program. About one fifth of pediatric centers cited lack of an adult CF physician as an impediment to establishing an adult program. Age (82% of programs; mean, 18.5 years), but not marriage (17.1%) or pregnancy (24.8%), was used as a criterion for transfer. Criteria precluding transfer included patient/family resistance (51.4%), disease severity (50.5%), and developmental delay (46.7%). The concept of transfer is introduced to the patient and family at the time of diagnosis in a minority (14%) of programs. Over one half of the patients did not meet the adult team until the time of transfer. Pediatricians reported higher perceived parent, patient, pediatric staff, and adult staff concerns about transition issues than did adult program directors.We conclude that there is a lack of standardized programs for transfer of CF patients from a pediatric to an adult care setting, and that there are differences between pediatric and adult program directors' perceptions of concerns that CF patients, their families, and the medical teams have about transfer. These differences may impede the successful transition of patients into an adult program. Pediatr Pulmonol. 2001; 31:443–450. © 2001 Wiley‐Liss, Inc.
Gene expression signature of benign prostatic hyperplasia revealed by cDNA microarray analysis
Authors: Luo Jun , Dunn Thomas , Ewing Charles , Sauvageot Jurga , Chen Yidong , Trent Jeffrey , Isaacs William 
Published: August 2002

AbstractBACKGROUNDDespite the high prevalence of benign prostatic hyperplasia (BPH) in the aging male, little is known regarding the etiology of this disease. A better understanding of the molecular etiology of BPH would be facilitated by a comprehensive analysis of gene expression patterns that are characteristic of benign growth in the prostate gland. Since genes differentially expressed between BPH and normal prostate tissues are likely to reflect underlying pathogenic mechanisms involved in the development of BPH, we performed comparative gene expression analysis using cDNA microarray technology to identify candidate genes associated with BPH.METHODSTotal RNA was extracted from a set of 9 BPH specimens from men with extensive hyperplasia and a set of 12 histologically normal prostate tissues excised from radical prostatectomy specimens. Each of these 21 RNA samples was labeled with Cy3 in a reverse transcription reaction and cohybridized with a Cy5 labeled common reference sample to a cDNA microarray containing 6,500 human genes. Normalized fluorescent intensity ratios from each hybridization experiment were extracted to represent the relative mRNA abundance for each gene in each sample. Weighted gene and random permutation analyses were performed to generate a subset of genes with statistically significant differences in expression between BPH and normal prostate tissues. Semi‐quantitative PCR analysis was performed to validate differential expression.RESULTSA subset of 76 genes involved in a wide range of cellular functions was identified to be differentially expressed between BPH and normal prostate tissues. Semi‐quantitative PCR was performed on 10 genes and 8 were validated. Genes consistently upregulated in BPH when compared to normal prostate tissues included: a restricted set of growth factors and their binding proteins (e.g. IGF‐1 and ‐2, TGF‐β3, BMP5, latent TGF‐β binding protein 1 and ‐2); hydrolases, proteases, and protease inhibitors (e.g. neuropathy target esterase, MMP2, alpha‐2‐macroglobulin); stress response enzymes (e.g. COX2, GSTM5); and extracellular matrix molecules (e.g. laminin alpha 4 and beta 1, chondroitin sulfate proteoglycan 2, lumican). Genes consistently expressing less mRNA in BPH than in normal prostate tissues were less commonly observed and included the transcription factor KLF4, thrombospondin 4, nitric oxide synthase 2A, transglutaminase 3, and gastrin releasing peptide.CONCLUSIONSWe identified a diverse set of genes that are potentially related to benign prostatic hyperplasia, including genes both previously implicated in BPH pathogenesis as well as others not previously linked to this disease. Further targeted validation and investigations of these genes at the DNA, mRNA, and protein levels are warranted to determine the clinical relevance and possible therapeutic utility of these genes. Prostate 51: 189–200, 2002. © 2002 Wiley‐Liss, Inc.
Apoptotic activity of doxazosin on prostate stroma in vitro is mediated through an autocrine expression of TGF‐β1
Authors: Ilio Kenneth Y. , Park Irwin I. , Pins Michael R. , Kozlowski James M. , Lee Chung 
Published: August 2002

AbstractBackgroundDoxazosin, an alpha‐adrenergic antagonist, has been shown to induce apoptosis in prostatic stromal cells. The mechanism of this apoptotic action by Doxazosin remains undefined. The present study was carried out to demonstrate that the effect of Doxazosin on apoptosis of prostate stromal cells is mediated through an autocrine action of TGF‐β1.MethodsPrimary cultures of human prostate cells were treated with varying concentrations of Doxazosin (0, 0.1, 1, 10, and 100 μM) for a period up to 3 days. At the end of the 3‐day culture, cell numbers were counted. Apoptosis was assessed by a colorimetric terminal deoxyribonucleotide transferase labeling technique. TGF‐β1 was determined by enzyme‐linked immunosorbent assay (ELISA).ResultsCompared to control cultures, cell numbers were significantly decreased as much as 68.4% in cultures treated with 10 μM of Doxazosin after 3 days incubation, while apoptosis increased by 64.7% in cultures treated with the same concentration of Doxazosin after 24 h. This decrease in cell number was reversed when antibody to TGF‐β1 was added to these cultures. Addition of TGF‐β1 (0, 1.0, and 10 ng/mL) to the cultures also decreased the cell numbers. Quantitation of TGF‐β1 in lysates of cells by ELISA revealed that the cells treated with Doxazosin (10 μM) produced as much as 62.5% more TGF‐β1 than in that of untreated cells.ConclusionsThese results demonstrate that the apoptotic effect of Doxazosin on human prostatic stromal cells is mediated through an autocrine production of TGF‐β1. Prostate 48:131–135, 2001. © 2001 Wiley‐Liss, Inc.
Methylation and mutational analysis of p27kip1 in prostate carcinoma
Authors: Kibel Adam S. , Christopher Mathew , Faith Dennis A. , Bova G. Steven , Goodfellow Paul J. , Isaacs William B. 
Published: August 2002

AbstractBACKGROUNDWe have previously identified 12p12‐13 as a region of frequent genetic loss in prostate carcinoma. A candidate tumor suppressor gene at this locus is the cyclin dependent kinase inhibitor p27kip1, which has been implicated as a marker of aggressive prostate carcinoma. Herein, we examine metastatic prostate tumors, xenografts, and cell lines for gene inactivation via mutational inactivation or promoter hypermethylation.METHODSMutation analysis was performed on metastatic prostate tumors of 18 patients, eight prostate carcinoma cell lines, and 18 xenografts by PCR amplification of the entire open reading frame of p27kip1. PCR products were sequenced directly using internal primers. Methylation analysis was performed on four cell lines and nine xenografts using direct sequencing of cloned PCR products of bisulfite treated DNA. Presence of a CpG was consistent with methylation of that cytosine in the original sample.RESULTSWith the exception of the previously reported homozygous deletion, no additional mutations were identified. Methylated CpG residues were identified in three xenografts (LuCAP23, LuCAP35, and PC82) and the methylated residues clustered at six sites; the cytosines 69, 149, 191, 286, 349, and 487 base pairs 5′ of the ATG start codon. However, no sample demonstrated promotor methylation in all sequenced clones and the number of methylated base pairs ranged from seven to three, not the level usually associated with gene silencing.CONCLUSIONSMutational inactivation of p27kip1 is a rare event in metastatic prostate carcinoma. While CpG methylation does occur, it is an infrequent event and does not appear to be the mechanism of p27kip1 down regulation in prostate carcinoma. Prostate 48:248–253, 2001. © 2001 Wiley‐Liss, Inc.
2.8‐Å crystal structure of a nontoxic type‐II ribosome‐inactivating protein, ebulin l
Authors: Pascal John M. , Day Philip J. , Monzingo Arthur F. , Ernst Stephen R. , Robertus Jon D. , Iglesias Rosario , Pérez Yolanda , Férreras Jose Miguel , Citores Lucia , Girbés Tomás 
Published: August 2002

AbstractEbulin l is a type‐II ribosome‐inactivating protein (RIP) isolated from the leaves of Sambucus ebulus L. As with other type‐II RIP, ebulin is a disulfide‐linked heterodimer composed of a toxic A chain and a galactoside‐specific lectin B chain. A normal level of ribosome‐inactivating N‐glycosidase activity, characteristic of the A chain of type‐II RIP, has been demonstrated for ebulin l. However, ebulin is considered a nontoxic type‐II RIP due to a reduced cytotoxicity on whole cells and animals as compared with other toxic type‐II RIP like ricin. The molecular cloning, amino acid sequence, and the crystal structure of ebulin l are presented and compared with ricin. Ebulin l is shown to bind an A‐chain substrate analogue, pteroic acid, in the same manner as ricin. The galactoside‐binding ability of ebulin l is demonstrated crystallographically with a complex of the B chain with galactose and with lactose. The negligible cytotoxicity of ebulin l is apparently due to a reduced affinity for galactosides. An altered mode of galactoside binding in the 2γ subdomain of the lectin B chain primarily causes the reduced affinity. Proteins 2001;43:319–326. © 2001 Wiley‐Liss, Inc.