bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel synthesis of polyimide–polyhybridsiloxane block copolymers via polyhydrosilylation: Characterization and physical properties
Authors: Andre S. , Guida‐Pietrasanta F. , Rousseau A. , Boutevin B.
Published: August 2002

The insertion of soft polysiloxane segments into a polyimide backbone introduces changes in its properties (processability, low surface tension, gas permeability, and lower dielectric constant). Generally, these polyimide–polysiloxane copolymers are synthesized by the condensation of a dianhydride with an aromatic diamine and an amine telechelic polysiloxane, or by transimidization between an aminopyridine‐terminated oligoimide and an amine end‐capped oligosiloxane. This study investigated another route to obtain perfectly alternating polyimide–polyhybridsiloxane (PI–PHSX) block copolymers. The hydrosilylation, widely studied previously, was performed to elaborate copolymers from an allyl telechelic polyimide and a hydrosilane telechelic polyhybridsiloxane. The use of a telechelic polyhybridsiloxane as a soft segment brought better thermostability and better chemical resistance in comparison with an oligosiloxane based on Si(CH3)2O units. Using the same allyl telechelic polyimide moiety but varying the size of the hybrid siloxane part, we obtained different PI–PHSX block copolymers, leading to thermoplastic elastomers (TPE). We investigated the effect of the soft‐segment length on the thermal resistance, activation energy of thermal degradation, mechanical behavior, and surface properties of a series three PI–PHSX block copolymers containing 36, 54, and 75 wt % polyimide. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2414–2425, 2001
New polymer syntheses. CIX. Biodegradable, alternating copolyesters of terephthalic acid, aliphatic dicarboxylic acids, and alkane diols
Authors: Shaik Abbas‐Ali , Richter Martin , Kricheldorf Hans R. , Krüger Ralph‐P.
Published: August 2002

Copolyesters with an alternating sequence of terephthalic acid and aliphatic dicarboxylic acids were prepared with three different methods. First, dicarboxylic acid dichlorides were reacted with bis(2‐hydroxyethyl)terephthalate (BHET) in refluxing 1,2‐dichlorobenzene. Second, the same monomers were polycondensed at 0–20 °C in the presence of pyridine. Third, dicarboxylic acid dichlorides and silylated BHET were polycondensed in bulk. Only this third method gave satisfactory molecular weights. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry revealed that the copolyesters prepared by the pyridine and silyl methods might have contained considerable fractions of cyclic oligoesters and polyesters despite the absence of transesterification and backbiting processes. The alternating sequences and thermal properties were characterized with 1H NMR spectroscopy and differential scanning calorimetry measurements, respectively. In agreement with the alternating sequence, all copolyesters proved to be crystalline, but the crystallization was extremely slow [slower than that of poly(ethylene terephthalate)]. A second series of alternating copolyesters was prepared by the polycondensation of silylated bis(4‐hydroxybut‐ yl)terephthalate with various aliphatic dicarboxylic acid dichlorides. The resulting copolyesters showed significantly higher rates of crystallization, and the melting temperatures were higher than those of the BHET‐based copolyesters. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3371–3382, 2001
Ring‐opening polymerization of ϵ‐caprolactone by iodine charge‐transfer complex
Authors: De Queiroz Alvaro A. A. , França Écio J. , Abraham Gustavo A. , Román Julio S.
Published: August 2002

The ring‐opening polymerization of ϵ‐caprolactone (ϵ‐CL) catalyzed by iodine (I2) was studied. The formation of a charge‐transfer complex (CTC) among triiodide, I, and ϵ‐CL was confirmed with ultraviolet–visible spectroscopy. The monomer ϵ‐CL was polymerized in bulk using I2as a catalyst to form the polyester having apparent weight‐average molecular weights of 35,900 and 45,500 at polymerization temperatures of 25 and 70 °C, respectively. The reactivity of both, ϵ‐CL monomer and ϵ‐CL:I2CTC, was interpreted by means of the potential energy surfaces determined by semiempirical computations (MNDO‐d). The results suggest that the formation of the ϵ‐CL:I2CTC leads to the ring opening of the ϵ‐CL structure with the lactone protonation and the formation of a highly polarized polymerization precursor (ϵ‐CL)+. The band gaps approximated from an extrapolation of the oligomeric polycaprolactone (PCL) structures were computed. With semiempirical quantum chemical calculations, geometries and charge distributions of the protonated polymerization precursor (ϵ‐CL)+were obtained. The calculated band gap (highest occupied molecular orbit/lowest unoccupied molecular orbit differences) agrees with the experiment. The analysis of the oligomeric PCL isosurfaces indicate the existence of a weakly lone pair character of the CO and CO bonds suggesting a ϵ‐CL ring‐opening specificity. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 714–722, 2002
Probing multiple melting behaviors in poly(ethylene naphthalene 2,6‐dicarboxylate) with different thermal histories by simultaneous wide‐angle and small‐angle X‐ray scattering
Authors: Denchev Z. , Nogales A. , Šics I. , Ezquerra T. A. , Baltá‐Calleja F. J.
Published: August 2002

A simultaneous wide‐angle and small‐angle X‐ray scattering study of two poly(ethylene naphthalene 2,6‐dicarboxylate) samples crystallized from the glassy state at different annealing temperatures for different annealing times was carried out with synchrotron radiation. Either single or dual melting was induced in the samples, as confirmed by differential scanning calorimetry (DSC). The correlation function and interface distribution function were calculated to evaluate microstructural parameters such as the long spacing, the thickness of the amorphous and crystalline phases, and the width of the size distributions. The sample with dual melting behavior exhibited an abrupt increase of all microstructural parameters at temperatures above the melting of the lowest endotherm, whereas the sample revealing a single melting endotherm did not show such a sudden change. This finding agrees with the concept that the appearance of two melting peaks in DSC traces can be explained by the dual lamellar stacking model. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 881–894, 2001
Compatibilization efficiency of styrene–butadiene multiblock copolymers in PS/PP blends
Authors: Hlavatá D. , Horák Z. , Lednický F. , Hromádková J. , Pleska A. , Zanevskii Yu. V.
Published: August 2002

The compatibilizing effect of di‐, tri‐, penta‐, and heptablock (two types) copolymers with styrene and butadiene blocks was studied in polystyrene/polypropylene (PS/PP) 4/1 blends. The structure of PS/PP blends with the addition of 5 or 10 wt % of a block copolymer (BC) was determined on several scale levels by means of transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS). The results of the structure analysis were correlated with measured stress‐transfer properties: elongation at break, impact, and tensile strength. Despite the fact that the molar mass of the PS blocks in all the BCs used was about 10,000, that is, below the critical value M* (∼18,000) necessary for the formation of entanglements of PS chains, all the BCs used were found to be good compatibilizers. According to TEM, a certain amount of a BC is localized at the interface in all the analyzed samples, and this results in a finer dispersion of the PP particles in the PS matrix, the effect being more pronounced with S‐B‐S triblock and S‐B‐S‐B‐S pentablock copolymers. The addition of these two BCs to the PS/PP blend also has the most pronounced effect on the improvement of mechanical properties of these blends. Hence, these two BCs can be assumed to be better compatibilizers for the PS/PP (4/1) blend than the S‐B diblock as well as both S‐B‐S‐B‐S‐B‐S and B‐S‐B‐S‐B‐S‐B heptablock copolymers. In both types of PS/PP/BC blends (5 or 10 wt % BC), the BC added was distributed between both the PS/PP interface and the PS phase, and, according to SAXS, it maintained a more or less ordered supermolecular structure of neat BCs. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 931–942, 2001
Perfectly‐alternating linear (AB)nmultiblock copolymers: Effect of molecular design on morphology and properties
Authors: Spontak Richard J. , Smith Steven D.
Published: August 2002

Perfectly‐alternating linear (AB)nmultiblock copolymers consist ofnAB block pairs covalently linked in an alternating sequence. Although these copolymers can microphase‐order in the same fashion as their lower‐order (n= 1) diblock analogs, the 2(n− 1) biconformational midblocks comprising each copolymer molecule have a considerable impact on microstructural characteristics and bulk properties. We have applied transmission electron microscopy, differential scanning calorimetry (DSC), and extensional rheometry to examine and compare the morphologies and properties of two series of compositionally symmetric (lamellar) poly(styrene‐b‐isoprene)n(SI)n(1 ≤n≤ 4) multiblock copolymers. In one series, chain length was held constant allowing block mass (Mb) to decrease with increasingn. In the second copolymer series,Mbremained relatively invariant. Increasingnin these two series generally promoted reductions in both the lamellar period and upper (styrenic) glass‐transition temperature, but noticeable increases in tensile modulus and yield strength. These observed trends are more pronounced in the copolymer series with constant chain length due to the coupled relationship betweennandMb. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 947–955, 2001
Amphiphilic polymer gel electrolytes. II. Influence of the ethylene oxide side‐chain length on the gel properties
Authors: Gavelin Patrik , Ostrovskii Denis , Adebahr Josefina , Jannasch Patric , Wesslen Bengt
Published: August 2002

Amphiphilic polymers consisting of copolymethacrylates carrying about 26 wt % ethylene oxide [(EO)n] side chains of different lengths were used as matrices in gel electrolytes. The gel electrolytes were composed of 30 wt % copolymer and 70 wt % 1 M LiPF6 in a mixture of ethylene carbonate and γ‐butyrolactone (2/1 w/w). The coordination of lithium ions by the (EO)n side chains in competition with the solvent was studied by Raman spectroscopy. A significantly stronger lithium coordination was observed when the gel electrolyte was based on a copolymer carrying (EO)9 units in comparison with copolymers having (EO)1, (EO)2, and (EO)4 units. Despite the observed stronger lithium coordination by (EO)9 units in the gel, the ion conductivity was not significantly lower with respect to the gels based on the other copolymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1519–1524, 2001
The influence of hydrogen chloride doping level on the complex refractive indices of anisotropic polyaniline film: Application of a new internal reflection waveguide coupling technique
Authors: Liu Tao , Samuels Robert
Published: August 2002

Nondestructive three‐dimensional refractive‐index measurements are used for the determination of both crystallinity and orientation in thin polymer films. The prism waveguide coupler is particularly suitable for three‐dimensional isotropic and anisotropic thin‐film studies because of the quantitative character of the information obtained and the ease of data acquisition. It has been limited, however, to measuring the refractive index of optically transparent or weakly absorbing films. This study shows that a modified prism waveguide coupler can be used to determine the complex refractive index over a range from transparent to highly absorbing films from the internally reflected light intensity. Thus, both the refractive index, n, and the extinction coefficient, k, can be obtained. This method is used to determine the anisotropic three‐dimensional n and k values of spin‐coated emeraldine base and hydrogen chloride doped emeraldine salt polyaniline films. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2481–2490, 2001
Factors reported to influence the return to work of cancer survivors: a literature review
Authors: Spelten Evelien R. , Sprangers Mirjam A.G. , Verbeek Jos H.A.M
Published: August 2002

An overview is provided of research into the return to work of cancer survivors, examining both the rate of return to work and factors impacting this return. A series of literature searches was conducted on MEDLINE and PSYCLIT databases for the years 1985–1999. Studies had to focus on the patient's perspective and had to include either the percentage of return to work or factors associated with return to work. Case studies and studies of cancer as an occupational disease were excluded. The search identified 14 studies. The mean rate of return to work was 62% (range 30–93%). The following factors were negatively associated with return to work: a non‐supportive work environment, manual labour, and having head and neck cancer. Sociodemographic characteristics were not associated with return to work. For increasing age, associations were mixed. The increased survival rate of cancer patients warrants attention to the problems survivors may encounter upon their return to work. More systematic research is needed to establish more clearly the relative importance of factors associated with return to work of cancer survivors, which, in turn, would contribute to an increase in the labour‐participation of cancer survivors. Copyright © 2002 John Wiley & Sons, Ltd.
Lung function in diastrophic dysplasia*
Authors: Remes Ville , Helenius Ilkka , Peltonen Jari , Poussa Mikko , Sovijärvi Anssi
Published: August 2002

Diastrophic dysplasia (DD) is a rare skeletal dysplasia characterized by short‐limbed short stature, contractures and early degeneration of joints, and spinal deformities such as scoliosis. Mortality is increased in the neonatal period, in part due to tracheo‐ and bronchomalacia. Additionally, spinal deformities are very rigid, decreasing mobility of the chest cage. The aim of our study was to evaluate lung volumes and airway flow dynamics in patients with DD. A total of 31 patients (12 males, 19 females) underwent a detailed clinical examination measurements of standing height PA‐radiography of the spine, flow‐volume spirometry, and body plethysmography. The patients were assigned to two groups: children and adolescents (0–18 years, n = 18) and adults (over 18 years, n = 13).

The mean spirometric parameters were mostly within the predicted value range, although the variation was wide. At least one abnormally low spirometry parameter was found in 6 (33%) of the children and adolescents and in 7 (54%) of the adults. Mean forced vital capacity (FVC) was 104% (range 48–163%) of predicted values in the children and adolescents and 95% (58–140%) of the adults. Peak expiratory flow (PEF) values were abnormal in 4 (22%) of the children and adolescents and in 5 (39%) adults. The mean plethysmographic parameters were all within the predicted value range. At least one abnormal plethysmographic value was found in 6 (33%) of the children and adolescents and in 4 (31%) of the adults. Airway resistance (Raw) was significantly higher in the adults than in the children and adolescents (P = 0.016), and was abnormally high in 3 (23%) of the adults. The angle of thoracic or thoracolumbar scoliosis correlated with the percentages of the predicted values of FVC (rs = − 0.66), forced expired volume in 1 sec (FEV1) (rs = − 0.56), and total lung capacity (TLC) (rs = − 0.67). Age correlated with the FEV1/FVC ratio (rs = − 0.41), with the maximal expired flow at 50% FEV (MEF50) values (rs = − 0.55), with the residual volume (RV) values (rs = − 0.47), and with the RV/TLC ratio (rs = − 0.43). Variable bronchial obstruction was found in 1 (6%) child and in 2 (17%) adults.

Although the patients with DD had, on average, normal lung volumes, large individual variation occurred. Airway resistance was increased in adults. The angle of scoliosis correlated inversely with lung volume parameters. Pediatr Pulmonol. 2002; 33:277–282. © 2002 Wiley‐Liss, Inc.
Maternal history, sensitization to allergens, and current wheezing, rhinitis, and eczema among children in Costa Rica
Authors: Soto‐Quiros Manuel E. , Silverman Edwin K. , Hanson Lars Å. , Weiss Scott T. , Celedón Juan C.
Published: August 2002

Little is known about the factors associated with asthma, allergic rhinitis, and eczema in Latin American countries. We investigated the relation between potential risk factors and current wheezing, allergic rhinitis, and eczema among 208 Costa Rican children aged 10–13 years participating in phase II of the International Study of Asthma and Allergies in Childhood (ISAAC).

The geometric mean ( ± SD) serum total IgE level of children with current wheezing was significantly higher than that of children without current wheezing (533.8 ± 5.2 vs. 144.7 ± 6.0 IU/mL, P < 0.01). In a multivariate analysis, a maternal history of asthma, skin test reactivity (STR) to house dust mites, and STR to Alternaria were significantly associated with current wheezing. Children who had a maternal history of asthma had 2.4 times higher odds of current wheezing than those without maternal history of asthma (95% CI for OR = 1.1–5.3). Sensitization to either house dust mite or Alternaria was associated with 3.3 times increased odds of current wheezing (95% CI for OR for STR to dust mite = 1.6–6.7; 95% CI for OR for STR to Alternaria = 1.1–11.0). In a multivariate analysis, STR to house dust mite and STR to cat dander were significantly associated with allergic rhinitis, and a maternal history of eczema and STR to dog dander were associated with eczema in the child.

The interaction between familial factors and lifestyle changes resulting from social reforms implemented 60 years ago may explain the high prevalence of atopic diseases in Costa Rica. Pediatr Pulmonol. 2002; 33:237–243. © 2002 Wiley‐Liss, Inc.
Noninvasive investigation of hepatopulmonary syndrome in children and adolescents with chronic cholestasis
Authors: Santamaria Francesca , Sarnelli Paola , Celentano Luigi , Farina Vincenzo , Vegnente Angela , Mansi Antonio , Montella Silvia , Vajro Pietro
Published: August 2002

Early detection of hepatopulmonary syndrome (HPS) may be delayed because of invasiveness of the diagnostic procedures. In this pilot study, we prospectively investigated the usefulness of determining transcutaneous O2 tension after 100% O2 (TcPO2100) breathing using a transcutaneous hyperoxia test (THT) in 11 children with chronic cholestasis and without primary cardiopulmonary disease. These patients also underwent alveolar‐arterial O2 gradient testing (AaDO2) at an inspired oxygen fraction (FiO2) of 0.21, lung scintiscan, and contrast transthoracic echocardiography (TTE). Three of them had a liver transplantation because of the downhill course of their liver disease and respiratory status.

THT transcutaneous O2 tension at 21% FiO2 (TcPO221) was 75 ± 13 mmHg, and increased to 488 ± 106 mmHg after 100% O2 breathing (TcPO2100). Both mean values were not significantly different from those found in 8 age‐matched controls (P = 0.9 and P = 0.5, respectively). However, one patient, in spite of her stable liver function, showed an abnormal TcPO221 and TcPO2100 (45 mmHg and 210 mmHg, respectively). This same subject was also the only patient with abnormalities of AaDO2 (54.2 mmHg; normal value, < 20 mmHg), lung scintiscan (brain/lung ratio of technetium‐99 fixation (B/L SI) = 9, normal value < 1), and TTE, suggesting intrapulmonary vasodilatations and shunts. Given the clinical development of cyanosis and platypnea, all criteria for HPS were fulfilled, and timing of her liver transplantation was therefore accelerated. This resulted in HPS regression.

In children with chronic cholestasis, repeated transcutaneous bedside measurements are a rapid and reliable noninvasive test for characterizing the severity of abnormal oxygenation, and may prove useful also in liver posttransplantation monitoring. Pediatr Pulmonol. 2002; 33:374–379. © 2002 Wiley‐Liss, Inc.
Evidence of early systemic activation and transendothelial migration of neutrophils in neonates with severe respiratory distress syndrome
Authors: Sarafidis Kosmas , Drossou‐Agakidou Vasiliki , Kanakoudi‐Tsakalidou Florence , Taparkou Anna , Tsakalidis Christos , Tsandali Chaido , Kremenopoulos Georgios
Published: August 2002

Several observations imply that the early inflammatory response involving activated neutrophils, tissue macrophages, and cytokines plays an important role in the pathogenesis of neonatal respiratory distress syndrome (RDS) and progression to bronchopulmonary dysplasia (BPD). The aim of this study was to test the hypothesis that changes in circulating neutrophil number and function and plasma levels of cytokines, consistent with neutrophil activation and migration to the tissues, occur during the early stages of neonatal RDS. For this purpose we measured peripheral blood levels of certain immunological parameters that promote neutrophil activation and transendothelial migration. Twenty preterm neonates with severe RDS and 20 healthy infants matched for gestational age were the subjects. The absolute neutrophil count (ANC), and plasma levels of interleukin‐6 (IL‐6), granulocyte colony‐stimulating factor (G‐CSF), and sL‐selectin using an enzyme‐linked immunosorbent assay (ELISA), neutrophil CD11b expression, and respiratory burst activity (RBA) using flow cytometry, were measured within 24 h after birth.

The two groups were comparable regarding perinatal characteristics. None of the neonates studied had any clinical or laboratory evidence of infection by the time of blood sampling. The immunological investigation showed that the RDS neonates had significantly lower ANC (P = 0.032), higher expression of the CD11b on neutrophils (P = 0.0065), and higher G‐CSF and IL‐6 plasma levels (P = 0.0047 and P < 0.0001, respectively) in comparison to healthy preterm neonates. The neutrophil RBA and plasma sL‐selectin levels did not differ significantly between the two groups.

We conclude that in neonates with severe RDS, there is evidence of a systemic neutrophil activation early in the course of the disease, supporting the view of a contributing role of activated neutrophils in the pathogenesis of RDS. Pediatr Pulmonol. 2001; 31:214–219. © 2001 Wiley‐Liss, Inc.
Insulin‐like growth factors and risk of benign prostatic hyperplasia†
Authors: Chokkalingam Anand P. , Gao Yu‐Tang , Deng Jie , Stanczyk Frank Z. , Sesterhenn Isabell A. , Mostofi F.K. , Fraumeni Joseph F. , Hsing Ann W.
Published: August 2002

BACKGROUND

Insulin‐like growth factors (IGFs) have potent growth mitogenic and anti‐apoptotic effects on prostate tissue, whereas IGF binding proteins (IGFBPs) inhibit growth of prostatic tissue. The IGF axis has been implicated in prostate cancer risk, but its role in benign prostatic hyperplasia (BPH) is unclear.

METHODS

Plasma levels of IGF‐I, IGF‐II, IGFBP‐1, and IGFBP‐3 were determined from the fasting bloods of 206 BPH cases admitted for treatment and 306 randomly selected population controls in Shanghai, China.

RESULTS

Relative to the lowest tertile, men in the highest tertile of IGF‐I levels had a significantly elevated risk of BPH (odds ratio [OR] = 2.80, 95% confidence interval [95% CI] = 1.60–4.92; Ptrend < 0.001). Results for IGF‐I were more pronounced after adjustment for serum androgens. In contrast, men in the highest IGFBP‐3 tertile had a significantly reduced risk (OR = 0.40; 95% CI = 0.23–0.69; Ptrend < 0.001). No associations of BPH with IGF‐II and IGFBP‐1 were observed.

CONCLUSION

As has been previously observed for prostate cancer, we found that IGF‐I and IGFBP‐3 are associated with BPH risk in China. Further investigation is needed to elucidate the role of the IGF axis in BPH etiology. Prostate 52: 98–105, 2002. Published 2002 Wiley‐Liss, Inc.
Metallothionein isoform 3 expression inhibits cell growth and increases drug resistance of PC‐3 prostate cancer cells
Authors: Dutta Rana , Sens Donald A. , Somji Seema , Sens Mary Ann , Garrett Scott H.
Published: August 2002

BACKGROUND

The third isoform of metallothionein (MT‐3) is overexpressed in prostate cancers and PIN lesions. The expression of MT‐3 is highly variable but appears to correlate to Gleason score. The goal of the present study was to determine the effect of MT‐3 overexpression on the growth of the PC‐3 prostate cancer cell line.

METHODS

PC‐3 cells were stably transfected with either the MT‐3 or MT‐1E gene. Cell growth was determined by counting DAPI‐stained nuclei, drug resistance by the colony formation assay, MT mRNA expression by reverse transcriptase‐polymerase chain reaction, and MT protein by immunoblot.

RESULTS

PC‐3 cells that overexpress the MT‐3 gene are growth inhibited compared with either untransfected cells, cells with blank vector, or cells with similar overexpression of the MT‐1E gene. Furthermore, increased chemotherapeutic drug resistance occurred in PC‐3 clones derived from MT‐3– and MT‐1E–transfected cells.

CONCLUSION

The overexpression of MT‐3 can influence the growth and chemotherapeutic drug resistance of the PC‐3 prostate cancer cell line. Prostate 52: 89–97, 2002. © 2002 Wiley‐Liss, Inc.
Reduction of wild type p53 function confers a hormone resistant phenotype on LNCaP prostate cancer cells*
Authors: Burchardt Martin , Burchardt Tatjana , Shabsigh Ahmad , Ghafar Mohamed , Chen Min‐Wei , Anastasiadis Aristotelis , de la Taille Alexandre , Kiss Alex , Buttyan Ralph
Published: August 2002

BACKGROUND

The protein encoded by the p53 gene is required for some forms of apoptosis and loss or mutations in this gene are found with increased frequency in advanced and hormone resistant human prostate cancers. In order to better appreciate whether reduction of wildtype p53 function in prostate cancer cells might contribute to the development of therapeutic‐resistance by these cells, we created stable variants of the androgen‐responsive, wild type p53‐expressing human prostate cancer cell line, LNCaP, by transfection with expression vectors designed to reduce expression or function of wildtype p53 in them. These cells were then tested for their ability to form tumors in castrated male nude mice.

METHODS

A conditional eukaryotic expression vector (under tetracycline regulation) expressing antisense p53 cDNA was constructed and either directly transfected into LNCaP cells or tranduced into these cells using recombinant retroviruses containing the vector. Stably transfected/transduced cells (LNCaP/Asp53) were evaluated by Western blot analysis for the ability of doxycycline to reduce p53 protein expression and for their ability to form tumors in castrated male nude mice treated or untreated with doxycycline. Additionally, we derived an LNCaP subline (LNCaP/DD) stably expressing a dominant‐negative form of p53 and tested these cells for their ability to form tumors in castrated male nude mice.

RESULTS

LNCaP/Asp53 cells showed reduced expression of p53 protein when cultured in a medium containing doxycycline and tested sublines were able to efficiently form tumors in castrated male nude mice only when the mice were treated with doxycycline. LNCaP/DD cells were readily able to form tumors in castrated male nude mice whereas parental LNCaP cells or control‐transfected LNCaP cells were not.

CONCLUSION

Loss of wildtype p53 function can contribute to the phenotype of hormone resistance of prostate cancer cells. Prostate 48:225–230, 2001. © 2001 Wiley‐Liss, Inc.
Interferon‐alpha prevents selection of doxorubicin‐resistant undifferentiated‐androgen‐insensitive metastatic human prostate cancer cells
Authors: Kuniyasu Hiroki , Yasui Wataru , Pettaway Curtis A. , Yano Seiji , Oue Naohide , Tahara Eiichi , Fidler Isaiah J.
Published: August 2002

BACKGROUND

We determined whether treatment of metastatic prostate cancer cells with doxorubicin (DOX) and interferon‐alpha (IFN‐α) prevented the emergence of highly undifferentiated tumor cells.

METHODS

The state of cell differentiation was determined by analysis of prostate‐specific antigen (PSA), E‐cadherin, keratin, and vimentin.

RESULTS

Human prostate cancer LNCaP‐LN3 cells growing in culture as multicell spheroids expressed higher levels of E‐cadherin and E‐cadherin‐associated β‐catenin than LNCaP‐LN3 cells growing as monolayers. Treatment of cells with DOX downregulated PSA, E‐cadherin, and keratin, and upregulated expression of vimentin and vascular endothelial growth factor (VEGF) mRNA. While treatment of cells with IFN‐α did not alter gene expression, the addition of IFN‐α to cultures treated with DOX produced synergistic toxicity and abrogated the changes in gene expression observed in cells treated with DOX alone.

CONCLUSIONS

Treatment with IFN‐α and DOX should be further explored as a therapeutic strategy for androgen‐insensitive prostate cancer. Prostate 49:19–29, 2001. © 2001 Wiley‐Liss, Inc.
Pro‐apoptotic and immunomodulatory activity of a mycobacterial cell wall‐DNA complex towards LNCaP prostate cancer cells
Authors: Reader S. , Ménard S. , Filion B. , Filion Mario C. , Phillips N.C.
Published: August 2002

Background

We have isolated a mycobacterial cell wall‐DNA complex (MCC) possessing anti‐cancer activity against bladder cancer cells. The anti‐cancer activity of MCC appears to be due to two effects: a direct interaction with bladder cancer cells resulting in the induction of apoptosis and an indirect effect via the stimulation of monocytes and macrophages cytokine synthesis. In this study, the direct effect of MCC towards LNCaP cancer cells was evaluated.

Methods

Inhibition of proliferation, cell cycle arrest and induction of apoptosis were evaluated in vitro using LNCaP cells treated with MCC. The synthesis of IL‐12, GM‐CSF, and TNF‐α by LNCaP cells in response to MCC was also determined. Experiments were performed to gain insight into the mechanism of action of MCC towards LNCaP cells.

Results

MCC caused a dose‐dependent inhibition of the proliferation of LNCaP cells that was associated with cell cycle arrest at the G0/G1 phase. MCC‐induced apoptosis of LNCaP cells was consistent with a mitochondrial pathway involving mitochondrial disruption, release of cytochrome c, and an increase in Bax protein levels leading to caspase‐3 and ‐7 activation and cleavage of poly (ADP‐ribose) polymerase and nuclear mitotic apparatus protein. Surprisingly, MCC also directly induced the synthesis of IL‐12 and GM‐CSF, but not TNF‐α, by LNCaP cells.

Conclusions

MCC possesses the ability to directly induce apoptosis of LNCaP cells and to trigger the synthesis of IL‐12 and GM‐CSF by these cells, suggesting a potential role of MCC for the treatment of prostate cancer. Prostate 49:155–165, 2001. © 2001 Wiley‐Liss, Inc.
Stable lower PAR expression decreased DU145 prostate cancer cell growth in SCID mice
Authors: Platica Micsunica , Ivan Elena , Chen Sheryl , Holland James F. , Gil Juan , Mandeli John , Platica Ovidiu
Published: August 2002

Background

PAR is a novel gene ubiquitously expressed in normal and malignant tissues with a trend towards higher expression in tumor cells. PAR biological function is unknown. Here we report the effect of lowering PAR expression on in vitro and in vivo proliferation of DU145 cells.

Methods

Decreased PAR expression was achieved by stable transfection of DU145 cells with antisense PAR cDNA cloned in pCMV‐Script expression vector. The proliferative potential of DU145 transfectants was studied by cell counts, colony formation in soft agar, flow cytometry, and growth in severe combined immunodeficient (SCID) mice.

Results

DU145 transfectants exhibited a decreased cell proliferation in tissue culture and a low efficiency of colony formation in soft agar. Flow cytometry revealed an arrest of these cells in G2‐M phase of mitotic cycle. A dramatic decrease of tumor growth was observed when DU145 transfectant cells were inoculated in SCID mice, compared with controls. Histological examination of these tumors showed a marked decrease in cell density and in number of mitoses while control tumors showed a high cell density and numerous mitoses.

Conclusions

The data presented here provide the first evidence for PAR gene cellular function and its possible implication in malignant transformation. Prostate 49:200–207, 2001. © 2001 Wiley‐Liss, Inc.
Pyrethroid resistance and cross‐resistance in the German cockroach, Blattella germanica (L)
Authors: Wei Yuping , Appel Arthur G , Moar William J , Liu Nannan
Published: August 2002

A German cockroach (Blatella germanica (L)) strain, Apyr‐R, was collected from Opelika, Alabama after control failures with pyrethroid insecticides. Levels of resistance to permethrin and deltamethrin in Apyr‐R (97‐ and 480‐fold, respectively, compared with a susceptible strain, ACY) were partially or mostly suppressed by piperonyl butoxide (PBO) and S,S,S,‐tributylphosphorotrithioate (DEF), suggesting that P450 monooxygenases and hydrolases are involved in resistance to these two pyrethroids in Apyr‐R. However, incomplete suppression of pyrethroid resistance with PBO and DEF implies that one or more additional mechanisms are involved in resistance. Injection, compared with topical application, resulted in 43‐ and 48‐fold increases in toxicity of permethrin in ACY and Apyr‐R, respectively. Similarly, injection increased the toxicity of deltamethrin 27‐fold in ACY and 28‐fold in Apyr‐R. These data indicate that cuticular penetration is one of the obstacles for the effectiveness of pyrethroids against German cockroaches. However, injection did not change the levels of resistance to either permethrin or deltamethrin, suggesting that a decrease in the rate of cuticular penetration may not play an important role in pyrethroid resistance in Apyr‐R. Apyr‐R showed cross‐resistance to imidacloprid, with a resistance ratio of 10. PBO treatment resulted in no significant change in the toxicity of imidacloprid, implying that P450 monooxygenase‐mediated detoxication is not the mechanism responsible for cross‐resistance. Apyr‐R showed no cross‐resistance to spinosad, although spinosad had relatively low toxicity to German cockroaches compared with other insecticides tested in this study. This result further confirmed that the mode of action of spinosad to insects is unique. Fipronil, a relatively new insecticide, was highly toxic to German cockroaches, and the multi‐resistance mechanisms in Apyr‐R did not confer significant cross‐resistance to this compound. Thus, we propose that fipronil could be a valuable tool in integrated resistance management of German cockroaches.

© 2001 Society of Chemical Industry
Evaluation of PCR, IEF and ELISA techniques for the detection and identification of potato cyst nematodes from field soil samples in England and Wales
Authors: Ibrahim Said K , Minnis Stephen T , Barker Anthony D P , Russell Mike D , Haydock Patrick P J , Evans Kenneth , Grove Ivan G , Woods Simon R , Wilcox Andrew
Published: August 2002

Effective management of potato cyst nematodes (PCNs) requires simple, rapid and accurate identification and quantification of field populations. Soil samples from a survey of 484 fields in potato rotations in England and Wales were used to compare the identification and quantification of PCNs using IEF, PCR, ELISA and bait plant tests. The cyst counts and bait plant test revealed that 64.3% of field samples contained PCNs. Bait plant tests increased the detection rate of PCNs in field samples by 4–6.4%. This means that some infestations are cryptic and would not normally be detected by standard counts. IEF, PCR and ELISA methods distinguished between Globodera rostochiensis and G pallida and were able to register mixed populations; however they were not in full agreement. All methods suggested that G pallida is the dominant species in the field samples tested. The PCR results indicated that 66% of field samples contained pure G pallida, 8% contained pure G rostochiensis and 26% contained mixtures of the two species. Estimates of the relative process times taken per sample in the PCR, IEF and ELISA techniques are given.

© 2001 Society of Chemical Industry
Phototransformation of metoxuron [3‐(3‐chloro‐4‐methoxyphenyl)‐1,1‐dimethylurea] in aqueous solution
Authors: Boulkamh Abdelaziz , Harakat Dominique , Sehili Tahar , Boule Pierre
Published: August 2002

UV irradiation of metoxuron in aerated aqueous solution at 254 nm or between 300 and 450 nm led initially to an almost specific photohydrolysis of the C–Cl bond, resulting in the formation of 3‐(3‐hydroxy‐4‐methoxyphenyl)‐1,1‐dimethylurea (MX3) and hydrogen chloride. The quantum yield was determined to be 0.020 (±0.005) in solutions irradiated at 254 nm. Five minor photoproducts were also identified, in particular the dihydroxydimethoxybiphenyl derivatives resulting from the phototransformation of MX3. Irradiation increased the toxicity of an aqueous solution of metoxuron to the marine bacterium Vibrio fischeri.

© 2001 Society of Chemical Industry
Quantitative structure–activity studies of insect growth regulators: XIX. Effects of substituents on the aromatic moiety of dibenzoylhydrazines on larvicidal activity against the beet armyworm Spodoptera exigua
Authors: Nakagawa Yoshiaki , Smagghe Guy , Tirry Luc , Fujita Toshio
Published: August 2002

Larvicidal activity against the beet armyworm, Spodoptera exigua (Hübner), was measured after topical treatment for a series of N‐tert‐butyl‐dibenzoylhydrazines having various substituents in the benzoyl (A‐ring) moiety closer to the tert‐butyl group, the other benzoyl (B‐ring) moiety being unsubstituted. The effects of substituents on the larvicidal activity were analyzed using the classical quantitative structure–activity relationship (QSAR) procedure. Introduction of hydrophobic substituents with a small volume into any position was favourable to activity. The existence of electron‐withdrawing substituents at ortho positions was also favourable to activity. For multi‐substituted compounds, physico‐chemically unknown unfavourable factors were suggested to remain after separating common substituent effects derived from QSAR for mono‐substituted analogues. With the exception of the unsubstituted compound RH‐5849, the effect of substituents in the A‐ring moiety on the larvicidal activity was similar to those found with the lepidopteran rice stem borer, Chilo suppressalis (Walker). The larvicidal activity of RH‐5849 against S exigua was significantly lower than the value predicted from the correlation between activities against S exigua and C suppressalis. Topical treatment with piperonyl butoxide, a synergist inhibiting oxidative metabolism, slightly enhanced the larvicidal activity of RH‐5849 against S exigua.

© 2001 Society of Chemical Industry
PCR‐based detection of resistance to acetyl‐CoA carboxylase‐inhibiting herbicides in black‐grass (Alopecurus myosuroides Huds) and ryegrass (Lolium rigidum Gaud)
Authors: Délye Christophe , Matéjicek Annick , Gasquez Jacques
Published: August 2002

A simple method based upon allele‐specific PCR was developed to detect an isoleucine‐leucine substitution in the gene encoding chloroplastic acetyl‐coenzyme A carboxylase (ACCase) in two gramineous weeds: Lolium rigidum Gaud and Alopecurus myosuroides Huds. Analysis of 1800 A myosuroides and 750 L rigidum seedlings showed that the presence of ACCase leucine allele(s) conferred cross‐resistance to the cyclohexanedione herbicide cycloxydim and to the aryloxyphenoxypropionate herbicides fenoxaprop‐P‐ethyl and diclofop‐methyl. Seedlings containing ACCase leucine allele(s) could be either sensitive or resistant to the aryloxyphenoxypropionate herbicides haloxyfop‐P‐methyl and clodinafop‐propargyl. Successful detection of resistant plants in a field population of A myosuroides was achieved using this PCR assay. Using it with basic molecular biology laboratory equipment, the presence of resistant leucine ACCase allele(s) can be detected within one working day.

© 2002 Society of Chemical Industry
Structural restoration of historical buildings in seismic areas
Authors: Penelis George G
Published: August 2002

Techniques, materials and design procedures in use for the structural restoration of historical buildings and monuments in seismic areas are presented on a conceptual basis and in relation to the restoration principles as they are stated in the Venice Charter. In this respect, the dependence of the restoration on the preservation of the aesthetic and historical values of the buildings, the low reliability of their original textures and the limitations to the intervention materials and techniques, create a very strict frame of actions, which is a real challenge for the structural engineer.
Recent all‐composite and hybrid fibre‐reinforced polymer bridges and buildings
Authors: Keller Thomas
Published: August 2002

Fibre‐reinforced polymers (FRP) have found increased application in bridge and building construction in recent years. This is predominantly due to the advantageous properties of these materials, such as low self‐weight, high strength, free formability and substantial resistance to corrosion and fatigue. The development of FRP materials for use in new hybrid and all‐composite bridge and building construction from 1997 to the end of 2000 is described in this review.
Insect Repellent Activity of Diterpenoid Alkaloids
Authors: Ulubelen Ayhan , Meriçli Ali H. , Meriçli Filiz , Kilinçer Neşet , Ferizli A. Güray , Emekci Mevlut , Pelletier S. William
Published: August 2002

Diterpenoid and norditerpenoid alkaloids were tested against Tribolium casteneum (Herbst.) in order to assess their repellent activity. Of 29 tested alkaloids, 21 compounds showed promising insect repellent activity, while eight of them were not found to be active. The alkaloids were obtained from Delphinium, Consolida and Aconitum species. The highest activity was found in hetisine, a diterpene alkaloid (59.37%) and the lowest activity in another diterpene alkaloid venulol (31.25%). Copyright © 2001 John Wiley & Sons, Ltd.
Nematicidal activity of Trigonella foenum‐ graecum L.
Authors: Zia Tayyaba , Siddiqui Imran Ali , Nazrul‐Hasnain
Published: August 2002

The aqueous, methanol and chloroform extracts of Trigonella foenum‐graecum caused significant (p < 0.05) mortality of Meloidogyne javanica larvae. The methanol soluble fraction eluted from pure distilled water showed the highest (>92%) nematicidal activity compared with the fractions eluted from pure methanol and different ratios of chloroform and methanol indicate that the nematicidal compound was polar in nature. Copyright © 2001 John Wiley & Sons, Ltd.
Analgesic and antiinflammatory properties ofSideritis lotsyivar.Mascaensis
Authors: Hernández‐Pérez Margarita , Rabanal Gallego Rosa M.
Published: August 2002

The antiinflammatory, analgesic and antimicrobial activities of crude ethanol extracts ofSideritis lotsyivar.mascaensis(Lamiaceae), and chloroform and aqueous fractions were evaluated in mice using paw and ear oedema induced by carrageenan and 12‐o‐tetradecanoyl‐phorbol‐acetate (TPA), respectively, as inflammation models, the writhing test induced by acetic acid for evaluating analgesic activity and the disk‐diffusion method for testing antimicrobial actions.

The results obtained demonstrated significant topical antiinflammatory and analgesic activities for the ethanol extract and chloroform fraction, but no relevant antimicrobial activity against the microorganisms tested. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluation of the flora of Puerto Rico for in vitro antiplasmodial and antimycobacterial activities
Authors: Antoun M. D. , Ramos Z. , Vazques J. , Oquendo I. , Proctor G. R. , Gerena L. , Franzblau S. G.
Published: August 2002

The emergence of resistant strains of Plasmodium falciparum and
Mycobacterium tuberculosis underscores the need for novel drugs that are effective against these microorganisms.

As part of our screening programme of the flora of Puerto Rico, we tested a number of ethanol extracts of higher plants for antiplasmodial and antimycobacterial activities. A total of 40 extracts belonging to 23 plant families and 37 species were tested for antiplasmodial activity. Five extracts demonstrated activity against Plasmodium falciparum in vitro (50%–100% parasite suppression at 5 μg/mL).

Another 63 extracts belonging to 30 plant families and 50 species were tested in vitro against Mycobacterium tuberculosis. Two extracts were found to be active, Ficus citrifolia and Pisonia borinquena (85% or more inhibition of microbial growth at 100 μg/mL of extract). Copyright © 2001 John Wiley & Sons, Ltd.
The interrelation of changes in oxygen content and product quality in modified atmosphere packages of peanuts
Authors: Ucherek Marzena
Published: August 2002

The aim of this work was to examine the effect of changes in oxygen content in different types of packages for snacks (multilayer laminated materials, cans) and analyse the changes in the sensorial and physicochemical characteristics of the stored products. Roasted and salted peanuts produced by one of the well‐known companies, packed in modified atmosphere packages (MAP) were the object of this investigation. The interdependence of the changes in oxygen content and product quality was examined in relation to the storage period and type of package used. From the results it can be said that changes in oxygen content in packages of peanuts produce similar effects irrespective of the packaging material used. The correlation observed during storage of peanuts, between changes in oxygen content in different packaging materials and changes of the separate sensorial and physicochemical parameters of the product, especially of the peroxide value, may be a basis for validity forecasting and determination of the optimum composition of gas mixture. This study indicates that evaluation of the quality of packages integrally related to their content should consider both product examination and the package and gas mixture composition, as there may exist an interdependence between quality features of the product and oxygen content in a package. Copyright © 2001 John Wiley & Sons, Ltd.
Reactivity properties of derivatives of 2‐imidazoline: an ab initio DFT study
Authors: Cruz J. , Martínez‐Aguilera L. M. R. , Salcedo R. , Castro M.
Published: August 2002

The structural and electronic properties of a series of imidazoline (I) derivatives R1‐I‐R2 have been studied by means of density functional theory. The chosen compounds have different chain lengths (R1) and pendant (R2) groups, where R1=CH3, (CH2)nCH3 (n=2,4,…,16) and R2=H, CH3, C2H5, C3H7, C2H5OH, C2H5NH2, C2H5SH, C2H5COOH, and C2H5Cl. All‐electron calculations were carried out by means of the Gaussian‐98 program. Natural and Mulliken population analysis were determined for each of the neutral and charged molecules. The reactivity was analyzed in terms of the Fukui indices. The results indicate a high reactivity for both the tertiary (showing the biggest) and the iminic nitrogen atoms of the imidazoline ring. Although the N site of the pending groups has a much lower reactivity, this is significantly increased when a sulfur atom replaces it. In general, the reactivity of the N atoms of the ring depends significantly on the substituents. As expected, the frontier molecular orbitals, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO), also describe the reactivity behavior. As the size of the R1 chain increases, the two N atoms of the ring increase their nucleophilic character, since the HOMOs become more highly located. The obtained results help to explain the observed increased activity of these derivatives when they are used as inhibitors of corrosion moieties on metallic surfaces. Finally, the solvent effects on the ground‐state geometry were studied for one of the most promising reactive imidazolines; for which its interaction with an iron oxide surface was also addressed. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001