bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multivariate calibration stability: a comparison of methods
Authors: Marx Brian D. , Eilers Paul H. C. 
Published: October 2002

AbstractIn the multivariate calibration framework we revisit and investigate the prediction performance of three high‐dimensional modeling strategies: partial least squares, principal component regression and P‐spline signal regression. Specifically we are interested in comparing the stability and robustness of prediction under differing conditions, e.g. training the model under one temperature and using it to predict under differing temperatures. An example illustrates stability comparisons. Copyright © 2002 John Wiley & Sons, Ltd.
Hard‐modelled trilinear decomposition (HTD) for an enhanced kinetic multicomponent analysis
Authors: Neuhold Yorck‐Michael , Maeder Marcel 
Published: October 2002

AbstractWe present a novel approach for kinetic, spectral and chromatographic resolution of trilinear data sets acquired from slow chemical reaction processes via repeated chromatographic analysis with diode array detection. The method is based on fitting rate constants of distinct chemical model reactions (hard‐modelled, integrated rate laws) by a Newton–Gauss–Levenberg/Marquardt (NGL/M) optimization in combination with principal component analysis (PCA) and/or evolving factor analysis (EFA), both known as powerful methods from bilinear data analysis. We call our method hard‐modelled trilinear decomposition (HTD). Compared with classical bilinear hard‐modelled kinetic data analysis, the additional chromatographic resolution leads to two major advantages: (1) the differentiation of indistinguishable rate laws, as they can occur in consecutive first‐order reactions; and (2) the circumvention of many problems due to rank deficiencies in the kinetic concentration profiles. In this paper we present the theoretical background of the algorithm and discuss selected chemical rate laws. Copyright © 2002 John Wiley & Sons, Ltd.
Multivariate data analysis and bivariate regression studies applied to comparison of two multi‐elemental methods for analysing wine samples
Authors: Sagrado S. , Pérez‐Jordan M. Y. , Pastor A. , Salvador A. , de la Guardia M. 
Published: October 2002

AbstractTwo inductively coupled plasma mass spectrometry (ICP‐MS) methods which permit multi‐elemental analysis in wine samples have been compared following two strategies. First, a multivariate tool based on principal component analysis (PCA) was employed for a global (all analytes) qualitative comparison of the two methods. A single plot based on the confidence limits of the Q and T2 PCA model statistics corresponding to the ‘standard’ method results (calibration set) was used to check the comparability of the ‘candidate’ method (test samples). The residual matrix (after test matrix interpolation into the PCA model) gives qualitative information about the nature of the main errors. This approach is compatible with the presence of missing data. Second, comparison of the methods, analyte by analyte, based on bivariate least squares (BLS) regression was used. This approach, which uses the uncertainty information from both methods and performs a joint test for the intercept and slope parameters, permits appropriate comparison when the two methods have non‐constant standard deviations. Copyright © 2002 John Wiley & Sons, Ltd.
Mechanism of asymmetric hydrogenation by rhodium complexes with unsymmetrical P‐chirogenic bisphosphine ligands
Authors: Ohashi Atsushi 
Published: October 2002

AbstractUsing a series of the rhodium complexes with (1S,2S)‐1‐(R1)methylphosphino‐2‐(R2)(R3)phosphinoethane (R1, R2 and R3 = 1‐adamantyl, t‐butyl, cyclohexyl, cyclopentyl, methyl; abbreviated as unsymmetrical BisP*), very high enantioselectivities were observed when the di‐ or tri‐ substituted and tetra‐substituted dehydro‐α‐amino acid derivatives were used as the substrates. The main factor to give high enantioselectivity is the repulsive interaction between the functional groups of the substrate and the bulky substituents of the unsymmetrical BisP*. Since the unsymmetrical BisP* has two independent chiral phosphorous atoms in the vicinity of the active site, the higher enantioselectivity than those by the C2 symmetric BisP* complexes can be obtained. Moreover, the fine‐tuning to obtain extremely high enantioselectivity may be possible by changing the combination of the substituents on the two phosphorous atoms of the unsymmetrical BisP*. Chirality 14:573–577, 2002. © 2002 Wiley‐Liss, Inc.
Enantioselectivity in the steady‐state pharmacokinetics and transplacental distribution of pindolol at delivery in pregnancy‐induced hypertension
Authors: Gonçalves Paulo Vinicius Bernardes , Matthes Ângelo Do Carmo Silva , Da Cunha Sérgio Pereira , Lanchote Vera Lucia 
Published: October 2002

AbstractNine patients taking oral doses of 10 mg/12 h rac‐pindolol as part of their treatment for hypertension in pregnancy were recruited for the study. Maternal and fetal gestational age ranged from 20–38 years and 28–41 weeks, respectively. Blood was collected from the umbilical cord vein and from the mother from zero to 12 h after drug administration. Urine was collected for 12 h after rac‐pindolol administration at the following intervals: 0–3, 3–6, 6–9, and 9–12 h. Plasma and urine concentrations of the pindolol enantiomers were determined by HPLC using a Chiralpak® AD chiral column and fluorescence detection. The data were fitted to a one‐compartment model and differences between (+)‐R and (−)‐S enantiomers were compared by the pairedt‐test (P< 0.05). Mean results are reported. The disposition of pindolol in maternal plasma was stereoselective, with higher AUC(84.34 vs. 95.69 ng.h/ml) and ClRvalues (9.16 vs. 10.85 L/h) and lower Vd/f (251.38 vs. 225.17 L) and Cl/f (62.48 vs. 55.74 L/h) for the (+)‐R pindolol. The transplacental distribution of pindolol was not stereoselective. Cord, plasma, and presumably fetal, concentrations of the pindolol enantiomers were 56% of the maternal plasma concentrations up to 6 h after the last dose. Chirality 14:683–687, 2002. © 2002 Wiley‐Liss, Inc.
Arabidopsis thaliana protein, ATK1, is a minus‐end directed kinesin that exhibits non‐processive movement
Authors: Marcus Adam I. , Ambrose J. Christian , Blickley Lisa , Hancock William O. , Cyr Richard J. 
Published: October 2002

AbstractThe microtubule cytoskeleton forms the scaffolding of the meiotic spindle. Kinesins, which bind to microtubules and generate force via ATP hydrolysis, are also thought to play a critical role in spindle assembly, maintenance, and function. The A. thaliana protein, ATK1 (formerly known as KATA), is a member of the kinesin family based on sequence similarity and is implicated in spindle assembly and/or maintenance. Thus, we want to determine if ATK1 behaves as a kinesin in vitro, and if so, determine the directionality of the motor activity and processivity character (the relationship between molecular “steps” and microtubule association). The results show that ATK1 supports microtubule movement in an ATP‐dependent manner and has a minus‐end directed polarity. Furthermore, ATK1 exhibits non‐processive movement along the microtubule and likely requires at least four ATK1 motors bound to the microtubule to support movement. Based on these results and previous data, we conclude that ATK1 is a non‐processive, minus‐end directed kinesin that likely plays a role in generating forces in the spindle during meiosis. Cell Motil. Cytoskeleton 52:144–150, 2002. © 2002 Wiley‐Liss, Inc.
Diverse chemotactic responses of Dictyostelium discoideum amoebae in the developing (temporal) and stationary (spatial) concentration gradients of folic acid, cAMP, Ca2+ and Mg2+
Authors: Korohoda Włodzimierz , Madeja Zbigniew , Sroka Jolanta 
Published: October 2002

AbstractThe responses of Dictyostelium discoideum amoebae to developing (temporal) and stationary (spatial) gradients of folic acid, cAMP, Ca2+, and Mg2+ were studied using the methods of computer‐aided image analysis. The results presented demonstrate that the new type of experimental chambers used for the observation of single cells moving within the investigated gradients of chemoattractants permit time lapse recording of single amoebae and determination of the trajectories of moving cells. It was found that, besides folic acid and cAMP (natural chemoattractants for Dictyostelium discoideum amoebae), also extracellular Ca2+ and Mg2+ are potent inducers of these cells' chemotaxis, and the amoebae of D. discoideum can respond to various chemoattractants differently. In the positively developing gradients of folic acid, cAMP, Ca2+, and Mg2+ oriented locomotion of amoebae directed towards the higher concentration of the tested chemoattractants was observed. However, in the negatively developing (temporal) and stationary linear (spatial) gradients, the univocal chemotaxis of amoebae was recorded only in the case of the Mg2+ concentration gradient. This demonstrates that amoebae can respond to both developing and stationary gradients, depending upon the nature of the chemoattractant. We also investigated the effects of chosen inhibitors of signalling pathways upon chemotaxis of D. discoideum amoebae in the positively developing (temporal) gradients of tested chemoattractants. Verapamil was found to abolish the chemotaxis of amoebae only in the Ca2+ gradients. Pertussis toxin suppressed the chemotactic response of cells in the gradients of folic acid and cAMP but did not prevent chemotaxis in those of Ca2+ and Mg2+, while quinacrine inhibited chemotaxis in the gradients of folic acid, cAMP, and Ca2+ but only slightly affected chemotaxis in the Mg2+ gradient. None of the tested inhibitors causes inhibition of cell random movement, when applied in isotropic solution. Also EDTA and EGTA up to 50 mM concentration did not inhibit locomotion of amoebae in control isotropic solutions. Cell Motil. Cytoskeleton 53:1–25, 2002. © 2002 Wiley‐Liss, Inc.
Significance of secondary ultrasonographic endometrial thickening in postmenopausal tamoxifen‐treated women
Authors: Cohen Ilan , Azaria Ron , Shapira Jeremiah , Yigael Dror , Tepper Ron 
Published: October 2002

AbstractBACKGROUNDUltrasonography has a limited value in endometrial assessment for identification of endometrial pathologies in postmenopausal tamoxifen‐treated patients.METHODSWe compared the rate of endometrial pathologies and the mean ± SD of endometrial thickness diagnosed after the first and second transvaginal ultrasonographic studies performed on 55 postmenopausal tamoxifen‐treated patients with secondary endometrial thickening (Group I). This rate was also compared with 46 similar patients without secondary thickening (Group II). We also compared the mean ± SD of endometrial thickness detected in various ultrasonographic studies, as well as various clinical features.RESULTSA significantly higher rate of endometrial pathologies, including two cases of endometrial cancer identified in gynecologically asymptomatic patients (3.6%), was diagnosed in Group I after the second study compared with the first study (52.7% and 9.1%, respectively; P = 0.001) and compared with those diagnosed after the second study in Group II (30.4%; P = 0.03). There was a significant increase (74.7 ± 115%) in endometrial thickness after the second study compared with the first study performed on Group I (10.7 ± 5.53 mm and 16.59 ± 5.53 mm, respectively; P = 0.0001) and a significant difference in endometrial thickness demonstrated in the second study performed on Groups I and II (16.59 ± 5.53 mm and 11.4 ± 3.91 mm, respectively; P = 0.001).There were no significant differences in the time elapsed since the diagnosis of breast carcinoma and from the beginning of tamoxifen treatment to the performance of the first ultrasonographic study as well as the time elapsed between the first and second studies performed.CONCLUSIONSA significant increase (> 50%) in secondary endometrial thickening, measured ultrasonographically, in postmenopausal tamoxifen‐treated patients, is associated with a high rate of endometrial pathologies, including endometrial cancer. Cancer 2002;94:3101–6. © 2002 American Cancer Society.DOI 10.1002/cncr.10587
Impact of thrombophilic gene mutations on thrombosis risk in patients with gastrointestinal carcinoma
Authors: Pihusch Rudolf , Danzl Gudrun , Scholz Michael , Harich Detlev , Pihusch Markus , Lohse Peter , Hiller Erhard 
Published: October 2002

AbstractBACKGROUNDPatients with malignancies have an increased risk for thromboembolic events due to the release of tissue factor by the tumor, damage to the vessel wall, and immobilization. Moreover, tumors may improve their growth and metastatic spread by utilizing the coagulation system. To date, no information is available on the additional role of prothrombotic mutations in these patients.METHODSThe prevalence of the factor V Leiden mutation (FVL) and the prothrombin G20210A mutation and of homozygosity for the methylenetetrahydrofolate reductase (MTHFR) C677T substitution has been analyzed in a cohort of 175 patients with gastrointestinal adenocarcinoma by the polymerase chain reaction‐restriction fragment length polymorphism technique.RESULTS6.9% of the patients were heterozygous for FVL, 5.7% were heterozygous for the prothrombin mutation, and 9.7% were homozygous for the MTHFR C677T mutation was detected in 9.7% of patients. Compared with the normal population, we found an increased prevalence of the prothrombin G20210A substitution (5.7% vs. 0.8%, P = 0.028). Thromboses were absent in 147 patients (Group A), whereas 28 of the patients suffered from thromboses during the period following tumor diagnosis (Group B). In Group A, 6.8% of the patients and 21.4% of the patients in Group B had a thrombosis before the diagnosis of cancer (P = 0.025, odds ratio [OR] 3.7). Heterozygous FVL was present in 4.8% of the patients in Group A and in 17.9% of the patients in Group B (P = 0.026, OR 4.4). In patients with thromboses before the detection of the tumor, the risk was elevated 6.3‐fold (25.0% vs 5.0%, P = 0.015). Heterozygosity for the prothrombin mutation and homozygosity for the MTHFR C677T substitution did not increase the incidence of thromboses.CONCLUSIONSWe demonstrated a significant effect of FVL on thrombosis in patients with malignant disease. Most thromboses occurred during the first months after tumor diagnosis, implicating diagnostic and therapeutic procedures as important nongenetic risk factors for venous thromboembolism. Our data also indicate that the prothrombin G20210A mutation may be a possible cofactor in cancer pathogenesis. Cancer 2002;94:3120–6. © 2002 American Cancer Society.DOI 10.1002/cncr.10590
Overexpression of cyclooxygenase‐2 is associated with a poor prognosis in patients with squamous cell carcinoma of the uterine cervix treated with radiation and concurrent chemotherapy
Authors: Kim Yong Bae , Kim Gwi Eon , Cho Nam Hoon , Pyo Hong Ryull , Shim Su Jung , Chang Sei Kyung , Park Hee Chul , Suh Chang Ok , Park Tchan Kyu , Kim Byung Soo 
Published: October 2002

AbstractBACKGROUNDThe objective of this study was to determine whether cyclooxygenase‐2 (COX‐2) overexpression was an indicator of prognosis in patients with International Federation of Gynecology and Obstetrics (FIGO) Stage IIB uterine cervical carcinoma who underwent radiation and concurrent chemotherapy.METHODSSeventy‐five patients with FIGO Stage IIB squamous cell carcinoma (SCC) of the uterine cervix who were treated with radiotherapy and concurrent chemotherapy between 1991 and 1996 were divided into two groups according to their COX‐2 level in an immunohistochemical study: the COX‐2 negative group (n = 54 patients) and the COX‐2 positive group (n = 21 patients). The clinicopathologic features, patterns of treatment failure, and survival data for patients in the COX‐2 positive group were compared with data from the patients in the COX‐2 negative group. Univariate and multivariate analyses were performed to determine the prognostic factors that influenced patient survival.RESULTSIn the immunohistochemical study, COX‐2 overexpression was observed in approximately 30% of patients with FIGO Stage IIB SCC of the uterine cervix. With delayed regression to the initial treatment, the treatment failure rate of patients in the COX‐2 positive group was much higher compared with the treatment failure rate of patients in the COX‐2 negative group. The higher incidence of central failure and lymph node failure for patients in the COX‐2 positive group was statistically significant (48% for the COX‐2 positive group vs. 13% for the COX‐2 negative group). However, there was no difference in the incidence of hematogenous metastases between the two groups (5% for the COX‐2 positive group vs. 7% for the COX‐2 negative group). In addition, increased COX‐2 expression in tumor cells also was correlated with a shorter interval to tumor recurrence (median interval to recurrence, 9 months in the COX‐2 positive group vs. 26 months in the COX‐2 negative group). Compared with patients in the COX‐2 negative group, patients in the COX‐2 positive group had lower overall actuarial and disease free survival rates (overall 5‐year actuarial survival rates: 56% for the COX‐2 positive group vs. 94% for the COX‐2 negative group; P = 0.003). Univariate and multivariate analyses showed that COX‐2 overexpression was an independent prognostic factor that surpassed other well‐known clinicopathologic parameters.CONCLUSIONSCOX‐2 overexpression can be used as a potent molecular risk factor in patients with FIGO Stage IIB SCC of the uterine cervix who are treated with radiotherapy and concurrent chemotherapy. Cancer 2002;95:531–9. © 2002 American Cancer Society.DOI 10.1002/cncr.10684
The relevance of prostatectomy findings for brachytherapy selection in patients with localized prostate carcinoma
Authors: Pisansky Thomas M. , Blute Michael L. , Hillman David W. , Davis Brian J. , Haddock Michael G. , Suman Vera J. , Wilson Torrence M. , Zincke Horst 
Published: October 2002

AbstractBACKGROUNDThe efficacy of brachytherapy for patients with localized prostate carcinoma depends on adequate radiotherapeutic coverage of the primary tumor and its subclinical extraprostatic extensions. Predictive models based on pretherapy factors may be useful to estimate the likelihood for clinically relevant extraprostatic disease and may be incorporated into selection criteria for this procedure.METHODSMultivariate logistic regression model building was performed using pretherapy factors in 2905 surgically staged patients with localized prostate carcinoma to estimate the probability of seminal vesicle and/or lymph node involvement. Bootstrap methods were employed to assess the stability of the final model parameters and to determine the sensitivity and specificity of the final model.RESULTSClinical tumor classification, biopsy Gleason score groupings, and serum prostate specific antigen (PSA) levels were associated with seminal vesicle and/or pelvic lymph node involvement. These factors were incorporated into a multivariate model that predicted for these adverse histopathologic features. Allowing for up to a 10% likelihood for seminal vesicle and/or pelvic lymph node involvement, patients with tumors classified as T1c–T2a, Gleason scores of 2–6, and PSA ≤ 16 ng/mL; or with tumors classified as T1c–T2a, Gleason scores of 7–10, and PSA ≤ 4 ng/mL; or with tumors classified as T2b–T2c, Gleason scores of 2–6, and PSA ≤ 6 ng/mL would be potential candidates for brachytherapy alone.CONCLUSIONSThe predictive model presented may provide criteria whereby an adequately performed prostate brachytherapy procedure is expected to encompass the intraprostatic and adjacent extraprostatic disease. Prostate brachytherapy alone may be considered in these circumstances, whereas the addition of external beam radiotherapy may be reserved for patients with disease that is apt to extend beyond the brachytherapy target volume. Cancer 2002;95:513–9. © 2002 American Cancer Society.DOI 10.1002/cncr.10697
Decreased Smad4 expression in the transforming growth factor‐β signaling pathway during progression of esophageal squamous cell carcinoma
Authors: Fukuchi Minoru , Masuda Norihiro , Miyazaki Tatsuya , Nakajima Masanobu , Osawa Hidenobu , Kato Hiroyuki , Kuwano Hiroyuki 
Published: October 2002

AbstractBACKGROUNDTransforming growth factor‐β (TGF‐β) has antiproliferative effects in various cells, and inactivation of the TGF‐β signaling pathway contributes to tumor progression or development. Smad4, a tumor suppressor gene, is a central mediator in the signaling pathways of the TGF‐β superfamily. This study was undertaken to clarify the correlation between Smad4 expression and the clinicopathologic characteristics of patients with esophageal squamous cell carcinoma (SCC). The authors also investigated the expression of components of the TGF‐β signaling pathway in seven established cell lines derived from esophageal SCC.METHODSImmunohistochemistry for Smad4 using monoclonal anti‐Smad4 antibody was performed on surgical specimens obtained from 80 patients with esophageal SCC. In seven cell lines, the authors examined the expression of components of the TGF‐β signaling pathway using Western and Northern blot analyses.RESULTSThere was a significant inverse correlation between Smad4 expression and both depth of invasion (P = 0.0008) and pathologic stage (P = 0.0079). The expression of Smad4 proteins could be detected in five of seven cell lines. The expression of TGF‐β type II receptor protein was decreased in two of seven cell lines, and the expression of both Smad2 and Smad3 proteins was decreased in only one cell line. The level of expression of Smad4 mRNA did not differ dramatically between cell lines and was not correlated with the quantity of Smad4 protein.CONCLUSIONSIn this study, the expression of Smad4 protein appeared to be correlated with the depth of invasion of esophageal SCC. The loss of Smad4 expression was not regulated at the level of transcription. Cancer 2002;95:737–43. © 2002 American Cancer Society.DOI 10.1002/cncr.10727