bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel camptothecin analogues that circumvent ABCG2‐associated drug resistance in human tumor cells
Authors: Yoshikawa Megumi , Ikegami Yoji , Hayasaka Shinya , Ishii Kazuyuki , Ito Akiko , Sano Kazumi , Suzuki Toshihiro , Togawa Tadayasu , Yoshida Hisahiro , Soda Hiroshi , Oka Mikio , Kohno Shigeru , Sawada Seigo , Ishikawa Toshihisa , Tanabe Shinzo 
Published: April 2004

AbstractIrinotecan (7‐ethyl‐10‐[4‐(1‐piperidino)‐1‐piperidino]‐carbonyloxycamptothecin; CPT‐11) is a widely used potent antitumor drug that inhibits mammalian DNA topoisomerase I (Topo I); however, overexpression of ABCG2 (BCRP/MXR/ABCP) can confer cancer cell resistance to SN‐38, the active form of CPT‐11. We have recently demonstrated that plasma membrane vesicles prepared from ABCG2‐overexpressing PC‐6/SN2‐5H cells transported SN‐38 and its glucuronide conjugate in an ATP‐dependent manner (Nakatomi et al., Biochem Biophys Res Commun 2001;288:827–32). In the present study, we have characterized a total of 14 new camptothecin (CPT) analogues with respect to both the inhibition of Topo I and the substrate specificity of ABCG2. All of the tested CPT analogues, which have different substitutions at positions 10 and 11, strongly inhibited the Topo I activity in a cell‐free system, as did SN‐38. Their antitumor activities in the SN‐38‐resistant PC‐6/SN2‐5H2 cell line greatly varied, however, being correlated with intracellular accumulation levels. We have examined ATP‐dependent transport of those CPT analogues by using plasma membrane vesicles prepared from both PC‐6/SN2‐5H2 cells and ABCG2‐transfected HEK‐293 cells. Based on the substrate specificity of ABCG2 thus evaluated, it is strongly suggested that CPT analogues with high polarity are good substrates for ABCG2 and are therefore effectively extruded from cancer cells. In this context, to circumvent ABCG2‐associated drug resistance, low‐polarity CPT analogues are considered to be potent lead compounds. The present study provides a practical approach to discover new CPT‐based drugs for the chemotherapy of drug‐resistant human cancer. © 2004 Wiley‐Liss, Inc.
Reduction of tumor progression and paraneoplastic syndrome development in murine lung adenocarcinoma by nonsteroidal antiinflammatory drugs
Authors: Peluffo Guillermo D. , Stillitani Isabel , Rodríguez Vanina A. , Diament Miriam J. , Klein Slobodanka M. 
Published: April 2004

AbstractMice bearing LP07 lung adenocarcinoma show some characteristics that are similar to those present in patients with NSCLC. LP07 tumor‐bearing mice develop the paraneoplastic syndromes of cachexia, leukocytosis and hypercalcemia. These symptoms may be partly due to a systemic inflammatory response. Our aim was to determine if treatment with NSAIDs would lower tumor and metastasis growth and their accompanying syndromes. The nonselective COX inhibitor indomethacin and the selective COX‐2 inhibitor celecoxib reduced tumor growth and metastasis outcome in s.c. LP07 tumor‐bearing mice. Both drugs also inhibited the development of leukocytosis and the weight loss associated with LP07 progression. Serum levels of the inflammatory cytokines IL‐1β and IL‐6, mediators of cachexia, were modulated by NSAIDs. Inhibition of in vitro migration and invasion and reduction in angiogenesis were attained when cells were treated with either indomethacin or celecoxib. MMP‐9 activity was also reduced in conditioned media from LP07 cells treated with celecoxib. These data suggest that several processes implicated in tumor progression can be modulated with NSAID treatment. Improvement in performance status through modulation of cachexia may offer a possibility for combining anti‐inflammatory treatments with more aggressive therapies. © 2004 Wiley‐Liss, Inc.
Hedgehog signalling in colorectal tumour cells: Induction of apoptosis with cyclopamine treatment
Authors: Qualtrough David , Buda Andrea , Gaffield William , Williams Ann C. , Paraskeva Christos 
Published: April 2004

AbstractHedgehog (Hh) signalling controls many aspects of development. It also regulates cell growth and differentiation in adult tissues and is activated in a number of human malignancies. Hh and Wnt signalling frequently act together in controlling cell growth and tissue morphogenesis. Despite the fact that the majority of colorectal tumours have a constitutively activated canonical Wnt pathway, few previous studies have investigated the expression of Hh signalling components in colorectal tumours. We describe here epithelial cell lines derived from both nonmalignant colorectal adenomas and colorectal adenocarcinomas that express both Sonic and Indian Hh. Interestingly, these cells also express the Hh receptor Patched and the downstream signalling components Smoothened and Gli1, suggesting autocrine Hh signalling in these cells. To test whether autocrine Hh signalling contributes to cell survival, we treated colorectal tumour cells with cyclopamine, a known inhibitor of Hh signalling. Cyclopamine treatment induced apoptosis in both adenoma‐ and carcinoma‐derived cell lines, which could be partially rescued by further stimulation of Hh signalling. These data suggest that autocrine Hh signalling can increase aberrant cell survival in colorectal tumour cells and may be a novel target for colon cancer therapy using drugs such as cyclopamine. © 2004 Wiley‐Liss, Inc.
Comparative cyclic stress–strain and fatigue resistance behavior of electron–beam‐ and gamma‐irradiated ultrahigh molecular weight polyethylene
Authors: Urriés I. , Medel F. J. , Ríos R. , Gómez‐Barrena E. , Puértolas J. A. 
Published: April 2004

AbstractFatigue‐related damage in UHMWPE is one of the main causes of long‐term failure in total joint replacements. Crosslinking ultrahigh molecular weight polyethylene (UHMWPE) by gamma or electron‐beam irradiation, in combination with prior or further thermal treatment, enhances its wear resistance against metallic components in total hip replacements, and eventually in knees. However, little information is available on the fatigue response of this modified UHMWPE. The objective of this study was to compare electron‐beam‐irradiated UHMWPE at 50, 100, and 150 kGy, with the well‐known 25 kGy gamma‐irradiated UHMWPE. Two different cyclic tests were performed under tensile stress, with a zero load ratio, R = 0. First, specimens were subjected to a sinusoidal load cycle at 1 Hz, which provided stress–life curves with the use of a failure criterion based on 12% yield strain. Second, specimens were tested under 50 load cycles at a displacement rate of 15 mm/min, which provided information about the evolution of secant modulus and plastic strain. The incubation period was also analyzed. DSC measurements were carried out to check the crystallization effect of irradiation. According to the results of fatigue resistance there was a crossover behavior between gamma‐ and electron‐beam‐irradiated UHMWPE regarding the applied stress. When the stress was higher than the crossover value, the fatigue resistance of γ‐irradiated samples was higher than electron‐beam‐irradiated ones. When the stress was lower, the fatigue behavior was the opposite. The crossover stress depended on the electron‐beam‐irradiation dose. The clinical relevance of this study lies in an improved knowledge of electron‐beam‐irradiated material under extreme mechanical circumstances, such as fatigue. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 152–160, 2004
Improvement of parallelization performance of GAMESS: Global sum and (semi‐)direct integral calculation in multireference perturbation calculation
Authors: Umeda Hiroaki , Koseki Shiro , Nagashima Umpei 
Published: April 2004

AbstractPerformance benchmark tests of the multireference perturbation theory (MRPT2) calculation in the GAMESS suite of programs have been performed on a 128‐node PC cluster system. The benchmark results point to two kinds of problems with GAMESS: network delay and slow access to disk files. To overcome these bottlenecks, we employ (semi‐)direct atomic orbital integral calculations and a new algorithm for the “global sum” operation. These modifications produce remarkable performance improvements, especially in the 128‐node PC cluster system, which was almost twice as fast in our version as in the original version. The modification of “global sum” also improved the performance of other types of molecular orbital calculations in GAMESS, such as density functional theory. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1175–1183, 2004
Processing, shedding, and endocytosis of membrane type 1‐matrix metalloproteinase (MT1‐MMP)
Authors: Osenkowski Pamela , Toth Marta , Fridman Rafael 
Published: April 2004

AbstractMatrix metalloproteinases (MMPs) are multidomain zinc‐dependent proteolytic enzymes that play pivotal roles in many normal and pathological processes. Some members of the MMP family are anchored to the plasma membrane via specialized domains and thus are perfectly suited for pericellular proteolysis. Membrane‐anchoring also confers the membrane type‐MMPs (MT‐MMPs) a unique and complex array of regulatory processes that endow cells with the ability to control MT‐MMP‐dependent proteolytic activity independently of the levels of endogenous protease inhibitors. Emerging evidence indicates that mechanisms as diverse as autocatalytic processing, ectodomain shedding, homodimerization and internalization can all contribute to the modulation of MT‐MMP activity on the cell surface. How these distinct processes interact to attain the optimal level of enzyme activity in a particular setting and the molecular signals that trigger them constitute a new paradigm in MMP regulation. This review will discuss the recent findings concerning these diverse regulatory mechanisms in the context of MT1‐MMP (MMP‐14). © 2004 Wiley‐Liss, Inc.
Extended field of view sonography: A useful tool in the diagnosis and management of abdominal pregnancy
Authors: Cotter Amanda M. , Jacques Elvire G. , Izquierdo Luis A. 
Published: April 2004

AbstractDiagnosis of abdominal pregnancy continues to be a challenge, resulting in delays in diagnosis and decision making. We report 2 cases of abdominal pregnancy for which extended field of view sonography contributed to both diagnosis and management. The shortcomings of MRI with respect to localizing the site of placental attachment are also discussed. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:207–210, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.20012
Vaginal calculus secondary to vaginal outlet obstruction
Authors: Malhotra Neena , Kumar Sunesh , Roy Kallol Kumar , Agarwal Rachna , Verma Vineeta 
Published: April 2004

AbstractPrimary vaginal stones are extremely rare and are often mistaken for bladder calculi on plain radiography. However, intravenous pyelography and sonography can help differentiate between the two. We report a case of a large vaginal stone in a 21‐year‐old woman referred for apareunia and difficult micturation. The clinical findings of vaginal outlet obstruction and a hard mass anterior to the rectum made us suspect a bladder calculus; however, sonography of the pelvis indicated that the mass was in the vagina. Further examination using a probe to physically define the stone's location confirmed it to be a vaginal calculus. Surgery was performed to repair the outlet obstruction and remove the stone, which permitted the woman to urinate normally and engage in normal sexual relations. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:204–206, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.20015
Sonographic anatomy of the cervical esophagus
Authors: Zhu Shang‐Yong , Liu Ruo‐Chuan , Chen Li‐Hong , Yang Hong , Feng Xu , Liao Xin‐Hong 
Published: April 2004

AbstractPurposeAlthough conventional sonography is used widely for evaluation of the gastroesophageal junction, its use in the cervical esophagus is still limited. The aim of this study was to assess the use of sonography to demonstrate this portion of the esophagus.MethodsThe cervical esophagi in 60 cadavers and 435 healthy volunteers were examined sonographically. Among the healthy subjects 182 were scanned with a transducer operating at 7.5 MHz, 183 with a 10.0‐MHz transducer, and 70 with a 12.0‐MHz transducer. Sonographic layer patterns were compared among the groups. Sonographic and histologic analyses were also performed on 3 cadaveric esophageal specimens to correlate the sonographic appearances with the anatomical findings.ResultsScans of the cadavers showed that the cervical esophagus lay between the trachea and vertebrae, with its origin at the midline; it gradually moved to the left as it descended toward the trunk. It moved to the right when the cadaver's head was turned to the left and the trachea was pushed gently to the left. Based on these anatomical characteristics, visualization of the cervical esophagus was optimized by scanning from both the left and the right lateral approaches, with manipulation of the trachea as needed. In scans of the 435 healthy subjects, the esophageal wall was shown as 5 layers in 423 (97.2%) and as 7 layers in the remaining 12 (2.8%). The demonstration rate of the 7‐layer pattern was significantly higher for subjects scanned at 12.0 MHz than for those scanned at 10.0 and 7.5 MHz (p < 0.01). The layers demonstrated sonographically corresponded to histological structures evident on microscopy.ConclusionsThe left lateral approach is essential to sonography of the cervical esophagus. However, the right wall of the esophagus is best seen from the right. In transverse scans, the cervical esophagus wall usually appears to be composed of 5 layers, although 7 layers can also appear, especially as the transducer frequency is increased. © 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:163–171, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu.20017
Enhanced gene transfer and cell death following p53 gene transfer using photochemical internalisation of glucosylated PEI‐DNA complexes
Authors: Ndoye Alioune , Merlin Jean‐Louis , Leroux Agnès , Dolivet Gilles , Erbacher Patrick , Behr Jean‐Paul , Berg Kristian , Guillemin François 
Published: April 2004

AbstractBackgroundp53 is frequently mutated in many cancers including human head and neck squamous cell carcinoma and pancreatic cancer. In tumor models, wild‐type (wt) p53 gene transfer induces apoptosis and tumor regression in vivo, justifying the extensive clinical investigation of p53 gene therapy.Methodsp53 nonviral‐mediated gene transfer was achieved using glucosylated polyethylenimine (PEI) in conjunction with photochemical internalisation (PCI). Experimental conditions were optimised using the green fluorescent protein (GFP) as a reporter. p53 gene transfer was then evaluated using semi‐quantitative RT‐PCR in p53‐deleted PANC3 and p53‐mutated FaDu cell lines. Following gene transfer, induction of apoptosis was investigated using phosphatidylserine externalisation and nuclear fragmentation assays. Induction of long‐term cell death was analysed using colony‐forming assays.ResultsPCI was found to enhance GFP gene transfer after 48 h in both cell lines. Whether using glucosylated‐PEI alone or associated with PCI, p53 gene transfer was achieved with subsequent recovery of p53 mRNA expression in PANC3 cells and a significant 4‐fold increase in p53 mRNA expression in FaDu cells. PCI was found to further enhance p53 mRNA expression by 2.3‐fold in PANC3 cells. Spontaneous induction of apoptosis following wt‐p53 gene transfer was achieved in both cell lines. PCI was found to enhance apoptosis up to levels similar to those achieved with chemotherapy. As a consequence, long‐term cell death was significantly enhanced after wt‐p53 gene transfer when PCI was used in both cell lines, yielding up to 60% cell death.ConclusionsPCI increases glucosylated‐PEI‐mediated p53 gene transfer, apoptosis as well as cell death in mutant p53 human cancer cells. Copyright © 2004 John Wiley & Sons, Ltd.
The myelinated axon is dependent on the myelinating cell for support and maintenance: Molecules involved
Authors: Edgar J.M. , Garbern J. 
Published: April 2004

AbstractThe myelin‐forming cells, oligodendrocytes and Schwann cells, extend processes that spirally wrap axons and provide the insulation that allows rapid saltatory conduction. Recent data suggest a further role for the myelin‐forming cells in axonal support and maintenance. This Mini‐Review summarises some of the data that support this view and highlights the molecules involved. © 2004 Wiley‐Liss, Inc.
A farinograph study on the viscoelastic properties of sago/wheat flour dough systems
Authors: Md Zaidul IS , Abd Karim A , Manan DMA , Ariffin A , Nik Norulaini NA , Mohd Omar AK 
Published: April 2004

AbstractDoughs containing mixtures of sago and wheat flours of differing protein content at different levels of sago substitution (10, 15, 20, 25, 30, 40 and 50%) were prepared as follows: sago + high protein wheat (HPW) flour, sago + medium protein wheat (MPW) flour and sago + low − protein wheat (LPW) flour. The viscoelasticity of doughs from control sago and wheat flours and sago/wheat flour mixtures was determined using a Braberder farinograph. It was found that arrival time increased with increasing protein content in the mixture. Peak time for control wheat flours and sago/wheat flour mixtures increased with increasing protein content. Dough stability, 20 min drop and water absorption were found to decrease as the sago proportion in the mixture decreased. The 50% sago/LPW mixture was unable to form a dough. Breakdown times for control HPW flour and HPW flour mixtures were the highest, followed by MPW flour and then LPW flour. However, breakdown time for control MPW flour was higher than that for HPW flour mixtures. The same trend was observed at all ratios of mixture over the whole experiment. Copyright © 2004 Society of Chemical Industry
Effects of tea leaf waste of green tea, oolong tea, and black tea addition on sudangrass silage quality and in vitro gas production
Authors: Kondo Makoto , Kita Kazumi , Yokota Hiro‐omi 
Published: April 2004

AbstractThis study evaluated the fermentation characteristics and in vitro gas production of sudangrass (Sorghum sudanese) silage with tea leaf waste of green tea, oolong tea and black tea added. All types of tea leaf waste contain large amounts of nitrogen (N) and tannins, and a small amount of low‐water‐soluble carbohydrates. Sudangrass was preserved without (control) and with green tea waste (GTW), oolong tea waste (OTW) or black tea waste (BTW) at rates of 50, 100 and 200 g kg−1 fresh matter in laboratory silos. The pH and butyric acid levels were significantly lower in GTW at all rates and in OTW at the 200 g kg−1 rate, whereas those levels were high in the control and BTW‐treated silage. Lactic acid level was appreciably higher in GTW‐ and OTW‐treated silage than the control and BTW‐treated silage. The addition of all types of tea waste increased the total N and tannins of the silage, whereas the acid detergent insoluble N was increased in the OTW‐ and BTW‐treated silage. GTW treatment increased gas production within a 96‐h period compared with the control, whereas OTW and BTW additions at 200 g kg−1 rates caused lower gas production. It is concluded that the fermentation characteristics and feed value of the silage incorporating with tea leaf wastes are different for these types of tea leaf. Among the three kinds of tea waste, GTW is the most valuable material as a silage additive. Copyright © 2004 Society of Chemical Industry
A comparison between buffalo (Bubalus bubalis) and cow (Bos taurus) rumen fluids in terms of the in vitro fermentation characteristics of three fibrous feedstuffs
Authors: Calabrò Serena , Williams Barbara A , Piccolo Vincenzo , Infascelli Federico , Tamminga Seerp 
Published: April 2004

AbstractRumen fluids from fistulated buffalos (Italy‐BRF) and cows (Netherlands‐CRF) were used as inocula to determine the fermentation kinetics of three forages. These were corn silage (CS), grass silage (GS) and wheat straw (WS) which had originated from both regions, giving six substrates in total. Fermentation kinetics was assessed by the measurement of cumulative gas production. Organic matter (OM) loss and volatile fatty acid (VFA) concentration at the end of the fermentation period were also determined. Both BRF and CRF ranked the substrates in the same order for total VFA, total gas production and the maximum rate of substrate degradation (CS > GS > WS). However, while the ranking of substrates was the same for both species, the absolute values differed significantly between the two inocula. Gas production, expressed as cumulative volume per unit mass of incubated (OMCV, ml g−1) and as cumulative volume per unit mass of OM degraded (OM ml g−1) for CRF was consistently higher than that for BRF for all substrates (p < 0.0001). VFA production, particularly of acetic and butyric acids, was significantly (p < 0.0001) lower for BRF than for CRF, though the digestibility of OM was the same for both inocula. VFA production predicted by the use of stoichiometric equations was generally higher than the observed gas production. These equations also predicted that the calculated amount of OM utilised for microbial growth was higher for BRF than for CRF. This may explain why diets having the same energy content but less protein can be fed to buffalo since they seem to have a lower requirement for protein compared with cattle. This possibility will need to be investigated in vivo. Given the similar ranking of feedstuffs between the two sources of inocula, these results suggest that either inoculum would be suitable for use in the cumulative gas production test as a measure of feedstuff evaluation. However, given the differences in absolute values, it is recommended that inocula from the species which will receive the feedstuff should be used. Copyright © 2004 Society of Chemical Industry
Phytate content is reduced and β‐glucanase activity suppressed in malted barley steeped with lactic acid at high temperature
Authors: Haraldsson Ann‐Katrin , Rimsten Lena , Alminger Marie Larsson , Andersson Roger , Andlid Thomas , Åman Per , Sandberg Ann‐Sofie 
Published: April 2004

AbstractThe effect of different steeping conditions on phytate, β‐glucan and vitamin E in barley during malting was studied by a full factorial experiment with three variables (steeping temperature, barley variety and steeping additions). Addition of lactic acid to the steeping water induced a reduction of phytate during steeping and germination, especially in combination with the high steeping temperature (48 °C). Furthermore, lactic acid and high temperature steeping inhibited β‐glucanase development, resulting in a well‐preserved β‐glucan content after germination. When steeping was conducted without addition of lactic acid, the low steeping temperature (15 °C) promoted development of both phytase and β‐glucanase activity during germination. A slightly higher level of tocopherols and tocotrienols was observed in samples steeped at 15 °C than in samples steeped at 48 °C. However, addition of lactic acid reduced the amount for both temperatures. When lactic acid bacteria were added to the steeping water none of the parameters studied differed from samples steeped with water only. The results show the possibility of combining phytate degradation with a preserved β‐glucan content during malting and can thus be of interest for development of cereal products with improved nutritional value. Copyright © 2004 Society of Chemical Industry