bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reconstitution of coupled fumarate respiration in liposomes by incorporating the electron transport enzymes isolated from Wolinella succinogenes
Authors: Biel Simone , Simon Jörg , Gross Roland , Ruiz Teresa , Ruitenberg Maarten , Kröger Achim 
Published: October 2003

Hydrogenase and fumarate reductase isolated from Wolinella succinogenes were incorporated into liposomes containing menaquinone. The two enzymes were found to be oriented solely to the outside of the resulting proteoliposomes. The proteoliposomes catalyzed fumarate reduction by H2 which generated an electrical proton potential (Δψ = 0.19 V, negative inside) in the same direction as that generated by fumarate respiration in cells of W. succinogenes. The H+/e ratio brought about by fumarate reduction with H2 in proteoliposomes in the presence of valinomycin and external K+ was approximately 1. The same Δψ and H+/e ratio was associated with the reduction of 2,3‐dimethyl‐1,4‐naphthoquinone (DMN) by H2 in proteoliposomes containing menaquinone and hydrogenase with or without fumarate reductase. Proteoliposomes containing menaquinone and fumarate reductase with or without hydrogenase catalyzed fumarate reduction by DMNH2 which did not generate a Δψ. Incorporation of formate dehydrogenase together with fumarate reductase and menaquinone resulted in proteoliposomes catalyzing the reduction of fumarate or DMN by formate. Both reactions generated a Δψ of 0.13 V (negative inside). The H+/e ratio of formate oxidation by menaquinone or DMN was close to 1.The results demonstrate for the first time that coupled fumarate respiration can be restored in liposomes using the well characterized electron transport enzymes isolated from W. succinogenes. The results support the view that Δψ generation is coupled to menaquinone reduction by H2 or formate, but not to menaquinol oxidation by fumarate. Δψ generation is probably caused by proton uptake from the cytoplasmic side of the membrane during menaquinone reduction, and by the coupled release of protons from H2 or formate oxidation on the periplasmic side. This mechanism is supported by the properties of two hydrogenase mutants of W. succinogenes which indicate that the site of quinone reduction is close to the cytoplasmic surface of the membrane.
Endochitinase activity in the apoplastic fluid of Phellinus weirii‐infected Douglas‐fir and its association with over wintering and antifreeze activity
Authors: Zamani A. , Sturrock R. , Ekramoddoullah A. K. M. , Wiseman S. B. , Griffith M. 
Published: October 2003

SummaryExtracellular proteins were extracted from Phellinus weirii infected Douglas‐fir (Pseudotsuga menziesii var. menziesii) roots and needles to examine endochitinase activity. Chitinases have been associated with the plant's defence response against fungal attack because they hydrolyse chitin, a structural component of fungal cell walls. Protein separation using sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE) followed by Western immunoblot analysis using a polyclonal antibody specific to an endochitinase‐like protein (ECP) resulted in the detection of up to three polypeptides between 27 and 30 kDa in size. Two‐dimensional gel electrophoresis (2‐D PAGE) followed by Western immunoblot analysis revealed that the apoplastic fluid contained multiple ECP isoforms with isoelectric points (pIs) ranging from 5.3 to 5.8 and molecular masses of 27–30 kDa. Chitinase activity in needle and root tissues was measured spectrophotometrically using a colorimetric assay. A gel overlay technique using glycol chitin as a substrate for endochitinase was applied to confirm that the ECP antibody detected an enzymatically active protein. The apoplastic fluid collected from P. weirii‐infected winter Douglas‐fir needles showed anti‐freeze activity and seasonal analysis of needle tissue showed some evidence of ECP accumulation in winter months. ECP was distributed systemically throughout the tree. Increased levels of endochitinase activity in the region of P. weirii infection supports a physiological role for ECP in the plant defence response.
Host responses to natural infection by Cytonaema sp. in the aerial bark of Eucalyptus globulus
Authors: Eyles A. , Davies N. W. , Yuan Z. Q. , Mohammed C. 
Published: October 2003

SummaryThe chemical and anatomical host responses to natural fungal infection by Cytonaema sp. in the aerial bark of 3‐year‐old Eucalyptus globulus plantation trees were examined. The lesion margin (LM) of the canker‐infected bark was characterized by the formation of a layer of dark extractives visible to the naked eye. Chemical analysis of the LM by gas chromatography‐mass spectrometry (GC‐MS), high‐performance liquid chromatography (HPLC) with ultraviolet detection and HPLC‐MS using negative ion electrospray ionisation indicated the presence of a range of compounds including hydrolysable tannins, polymeric proanthocyanidins, flavonoid glycosides, formlyated phloroglucinol compounds and volatile terpenes. These compounds were either undetectable in healthy tissue or present at significantly lower concentrations than in the LM. The LM of the canker‐infected bark was morphologically distinct from healthy phloem, its characteristics varying depending on severity of canker infection. In superficial infections in which only the phloem was affected, the following LMs were observed: (i) a continuous wound periderm of multiple layers, or (ii) an incompletely differentiated and discontinuous wound periderm. In cases of severe canker infections in which the vascular cambium had been killed, the new phloem formed subsequently contained traumatic oil glands in addition to the responses observed for superficial canker infections. All LMs were characterized by the formation of new parenchyma cells that stained positive for the presence of polyphenols. The significance of the chemical and structural responses as defence mechanisms against fungi causing stem canker is discussed.
Clinicopathological factors predicting recurrence of N0M0 renal cell carcinoma: A case series analysis of one facility
Authors: MASUDA AIICHIRO , AOKI MANA , TOKUNAGA MASATOSHI , USUI YUKIO , ABE TAKAYUKI , MIYAKITA HIDESHI , KINOSHITA HIDECHIKA , KAWAMURA NOBUO , TERACHI TOSHIRO 
Published: October 2003

AbstractBackground: Although many factors have been reported as predictors of the recurrence of renal cell carcinoma (RCC), none of the factors are consistent among different studies. In the study presented here, the potential clinicopathological predictors of the recurrence of N0M0 RCC were examined.Methods: A total of 201 patients who underwent nephrectomy for N0M0 RCC were examined to determine the pathological tumor stage (pT stage), pathological tumor grade of malignancy (tumor grade), symptoms, and tumor size.Results RCC recurred in 29 patients (14.4%), 50% of whom developed new tumors within 24 months after nephrectomy. The disease‐free 3‐ and 10‐year survival rates declined as the pT stage and tumor grade increased: these rates were, respectively, 98.6% and 86.5% for pT1a; 93.7% and 87.9% for pT1b; 100% and 100% for pT2; 78.6% and 58.0% for pT3a; and 88.9% and 16.7% for pT3b. Significant differences in the recurrence rate were noted between pT3 and pT1 or pT2, as well as between grade 3 disease and grade 1 or grade 2 tumors. Multivariate analysis showed that a combination of the pT stage, grade, and presence of symptoms was useful for predicting the recurrence of RCC.Conclusion: The present study showed that patients undergoing nephrectomy for N0M0 RCC should be followed‐up carefully for 2 years postoperatively with special attention to high pT stage, high grade, and the development of symptoms.
Epigenetics are involved in the regulation of the cell cycle and expression of tumor suppressor genes in human colon cancer cells
Authors: CHEN Ying Xuan , FANG Jing Yuan , LU Juan , YANG Li , QIU De Kai 
Published: October 2003

OBJECTIVE:  To investigate the effects of DNA methylation and histone acetylation on the cell cycle progression and expression of tumor suppressor genes in human colon cancer (HCC) cell lines.METHODS:  Three HCC cell lines (HT‐29, SW1116 and Colo‐320) were treated with the DNA methyl­ation inhibitor, 5‐aza‐2'‐deoxycytidine (5‐aza‐dC) or/and histone deacetylase (HDAC) inhibitors, tricho­statin A (TSA) or sodium butyrate. The methylation status of the promoter of the p16INK4A gene was assayed by methylation‐specific PCR (MSP). The expression of p16INK4A and p21WAF1 was analyzed by RT‐PCR. The cell cycle distribution was determined by flow cytometry.RESULTS:  Before treatment, p16INK4A expression was slightly detected in the three cell lines (HT‐29, SW1116 and Colo‐320) and p21WAF1 expression was not detected in SW1116 and Colo‐320 cells. The methylation level of the p16INK4A gene promoter significantly decreased and mRNA expression markedly increased in HT‐29 cells after treatment with 1 µmol/L, but not 10 µmol/L, of 5‐aza‐dC for 24 h. In the SW1116 and Colo‐320 cells, the expression of p16INK4A was markedly enhanced at 10 µmol/L or 5 µmol/L of 5‐aza‐dC for 24 h. However, p21WAF1 gene expression was not detected. Interestingly, after treatment with TSA or sodium butyrate, the transcription of p21WAF1 was significantly upregulated in these two cell lines. Furthermore, 5‐aza‐dC did not affect cell cycle distribution, but TSA or sodium butyrate blocked the cell cycle, mainly in the G1 phase.CONCLUSIONS:  The expression of the p16INK4A gene is regulated by DNA methylation in three HCC cell lines. The expression of p21WAF1 gene is regulated by histone acetylation in SW1116 and Colo‐320. In these two cell lines, histone hyperacetylation causes a G1 cell cycle arrest.
Evaluation of a rapid stoolantigen test for the diagnosis of Helicobacter pylori infection in Chinese patients
Authors: WONG WM , LAM SK , TONG TSM , CHEUNG KL , TANG VSY , XIA HHX , LAI KC , HU WHC , CHAN CK , YUEN MF , CHAN AOO , WONG BCY 
Published: October 2003

OBJECTIVE:  To evaluate the accuracy of a rapid assay that wasdeveloped to detect Helicobacter pylori antigen in the stool,using the principle of immunochromatography, in the Chinese population.METHODS:  Eligible patients without prior treatment of H.pylori were recruited. An in‐house rapid urease test (RUT) andhistology were used as the gold standard. The results of the rapidstool antigen test were compared with the gold standard.RESULTS:  Valid rapid stool antigen test results for interpretationwere obtained from 94 consecutive patients (mean age: 52.5, range:22−82 years). Sensitivity, specificity, positive predictivevalue, negative predictive value and accuracy were, respectively, 77.5%,87.0%, 81.6%, 83.9% and 83.0%.The test was easy to perform and results were available within 15 min.CONCLUSION:  The rapid stool antigen test using immunochromatography accuratelydiagnoses H. pylori infection in Chinese patients.
Extrahepatic manifestations of chronic hepatitis C
Authors: REMOROZA Roderick , WU George Y 
Published: October 2003

AbstractChronic hepatitis C virus (HCV) infection is associated with several extrahepatic disorders. Although the exact pathogenesis of these conditions is not fully understood, several studies have provided insight into the role of HCV in their development. This review discusses the different conditions that have been associated with HCV infection. Among the most commonly reported are cryoglobulinemia, membranoproliferative glomerulonephritis, leukocytoclastic vasculitis, Sjogren's syndrome, lichen planus and porphyria cutanea tarda. In some patients, these disorders are the first sign of HCV infection.
Matched case–control study to evaluate risk factors for hyperlactataemia in HIV patients on antiretroviral therapy
Authors: Datta D , Moyle G , Mandalia S , Gazzard B 
Published: October 2003

BackgroundLactic acidosis is a life‐threatening event during antiretroviral therapy (ART). Hyperlactataemia may be a prelude to acidosis. Our database study suggested that female gender, intercurrent illness and didanosine (ddI)‐based regimens may increase risk of lactic acidosis. The aim of this matched case–control study was to identify risk factors for hyperlactataemia requiring screening.MethodsCases were defined as patients with two consecutive lactate samples ≥3.5 mmol/L taken more than 1 week apart. Cases were matched to two controls on gender, use of ddI and total duration of therapy using a 6‐month window on either side. Controls never had raised lactate >2.5 mmol/L. A conditional logistic regression analysis using the PHREG procedure in SAS (SAS Institute Inc, Cary, NC) was performed with a discreet logistic model stratified by matching variables.ResultsTwenty‐one cases were matched to 42 controls. In the univariate model, current use of stavudine (d4T), total cholesterol >5.3 mmol/L and glucose levels ≥5.2 mmol/L gave increased likelihood of persistent hyperlactataemia. The multivariate model showed current use of d4T to be a significant independent predictor of persistent hyperlactataemia.Conclusions
The results of this case–control study indicate that, when controlling for ddI use, d4T use is an additional risk factor for hyperlactataemia.
Interleukin‐7 levels may predict virological response in advanced HIV‐1‐infected patients receiving lopinavir/ritonavir‐based therapy
Authors: Boulassel MR , Smith GHR , Gilmore N , Klein M , Murphy T , MacLeod J , LeBlanc R , Allan J , René P , Lalonde RG , Routy JP 
Published: October 2003

ObjectivesTo examine the relationship between levels of the T‐cell regulatory cytokine interleukin‐7 (IL‐7) and CD4 cell counts during immune reconstitution and to assess its prognostic value in advanced HIV‐1‐infected patients receiving lopinavir/ritonavir‐based therapy.MethodsThirty‐six HIV‐1‐infected adults who completed 48 weeks of follow‐up visits were included in this prospective study. Patients having failed two or more antiretroviral therapy regimens were treated with lopinavir/ritonavir‐based therapy. An enzyme‐linked immunosorbent assay was used to determine IL‐7 plasma levels, flow cytometry was used to analyse cell surface antigens, and polymerase chain reaction was used to quantify plasma HIV‐1.ResultsPretreatment IL‐7 levels were elevated in all patients (mean 11.0 pg/mL) and were negatively correlated with CD4 cell counts and age (r=−0.59, P<0.001 and r=−0.57, P<0.001, respectively). During the course of treatment, IL‐7 levels decreased by 34% while CD4 cell numbers progressively increased by 88%. Multivariate regression analysis showed that only pretreatment IL‐7 levels predicted viral load at 48 weeks when controlling for baseline CD4 cell counts, viral load and patient demographics.ConclusionsThese findings are consistent with regulation of T‐cell recovery by IL‐7, and suggest that IL‐7 measurements might be used to predict virological response.
Development of garnet porphyroblasts by multiple nucleation, coalescence and boundary misorientation‐driven rotations
Authors: Spiess R. , Peruzzo L. , Prior D. J. , Wheeler J. 
Published: October 2003

AbstractTwo types of garnet porphyroblast occur in the Schneeberg Complex of the Italian Alps. Type 1 porphyroblasts form ellipsoidal pods with a centre consisting of unstrained quartz, decussate mica and small garnet grains, and a margin containing large garnet grains. Orientation contrast imaging using the scanning electron microscope shows that the larger marginal garnet grains comprise a number of orientation subdomains. Individual garnet grains without subdomains are small (< 50 µm), faceted and idioblastic, and have simple zoning profiles with Ca‐rich cores and Ca‐poor rims. Subdomains of larger garnet grains are similar in size to the individual, small garnet grains. Type 2 porphyroblasts comprise only ellipsoidal garnet, with small subdomains in the centre and larger subdomains at the margin. Each subdomain has its own Ca high, Ca dropping towards subdomain boundaries. Garnet grains, with or without subdomains, all have the same Ca‐poor composition at rims in contact with other minerals. The compositional zonation patterns are best explained by simultaneous, multiple nucleation, followed by growth and amalgamation of individual garnet grains. The range of individual garnet and garnet subdomain sizes can be explained by a faster growth rate at the porphyroblast margin than in the centre. The difference between Type 1 and Type 2 porphyroblasts is probably related to the growth rate differential across the porphyroblast.Electron backscatter diffraction shows that small, individual garnet grains are randomly oriented. Large marginal garnet grains and subdomain‐bearing garnet grains have a strong preferred orientation, clustering around a single garnet orientation. Misorientations across subdomain boundaries are small and misorientation axes are randomly oriented with respect to crystallographic orientations. The only explanation that fits the observational data is that individual garnet grains rotated towards coincident orientations once they came into contact with each other. This process was driven by the reduction of subdomain boundary energy associated with misorientation loss. Rotation of garnet grains was accommodated by diffusion in the subdomain boundary and diffusional creep and rigid body rotation of other minerals (quartz and mica) around the garnet. An analytical model, in which the kinetics of garnet rotation are controlled by the rheology of surrounding quartz, suggests that, at the conditions of metamorphism, the rotation required to give a strong preferred orientation can occur on a similar time‐scale to that of porphyroblast growth.
Global Right Atrial Mapping Delineates Double Posterior Lines of Block in Patients with Typical Atrial Flutter:
Authors: CHEN JIAN , HOFF PER IVAR , ERGA KNUT STÅLE , ROSSVOLL OLE , OHM OLE‐JØRGEN 
Published: October 2003

Introduction: The crista terminalis (CT) has been shown to be a barrier to transverse conduction during typical atrial flutter (AFL). However, some studies have demonstrated the presence of functional block in the sinus venosa region but not at the CT. The aim of this study was to define these regions of block in the right atrium using a three‐dimensional noncontact mapping system. Methods and Results: In 39 AFL patients (33 men and six women, mean age 56 ± 13 years), a noncontact multielectrode array was used to reconstruct electrograms in the right atrium. Isochronal and isopotential propagation mapping was performed during AFL and during pacing from the coronary sinus ostium and the low lateral wall (cycle length from 600 to 240 msec) in sinus rhythm after creation of isthmus block. A single line of block along the CT area was found in 18 patients (46%). Two lines of block were found in 21 patients (54%), with the first line located along the CT area. The second was located in the sinus venosa region in 20 patients (51%) and in the lateral wall in 1 patient (3%). In all patients, the block in the lower part of the CT was observed during AFL (60%) and during pacing at all cycle lengths (48%–62%). The length and proportion of block were inversely proportional to pacing cycle length. Conclusion: Double lines of block were frequently observed in patients with AFL, and both lines may form the posterior boundaries of the AFL circuit. Block was fixed in the lower part of the CT and was functional in the upper part of the CT. (J Cardiovasc Electrophysiol, Vol. 14, pp. ***‐***, October 2003)
Prolonged Atrial Action Potential Durations and Polymorphic Atrial Tachyarrhythmias in Patients with Long QT Syndrome
Authors: KIRCHHOF PAULUS , ECKARDT LARS , FRANZ MICHAEL R. , MÖNNIG GEROLD , LOH PETER , WEDEKIND HORST , SCHULZE‐BAHR ERIC , BREITHARDT GÜNTER , HAVERKAMP WILHELM 
Published: October 2003

Introduction: Prolongation of the QT interval and torsades de pointes tachycardias due to altered expression or function of repolarizing ion channels are the hallmark of congenital long QT syndrome (LQTS). The same ion channels also contribute to atrial repolarization, and familial atrial fibrillation may be associated with a mutated KVLQT1 gene. We therefore assessed atrial action potential characteristics and atrial arrhythmias in LQTS patients. Methods and Results: Monophasic action potentials (MAPs) were simultaneously recorded from the right atrial appendage and the inferolateral right atrium in 10 patients with LQTS (8 with identifiable genotype) and compared to 7 control patients. Atrial arrhythmias also were compared to MAPs recorded in patients with persistent (n = 10) and induced (n = 4) atrial fibrillation. Atrial action potential durations (APD) and effective refractory periods (ERP) were prolonged in LQTS patients at cycle lengths of 300 to 500 msec (APD prolongation 30–41 msec; ERP prolongation 26–52 msec; all P < 0.05). Short episodes of polymorphic atrial tachyarrhythmias (polyAT, duration 4–175 sec) occurred spontaneously or during pauses after pacing in 5 of 10 LQTS patients, but not in controls (P < 0.05). P waves showed undulating axis during polyAT. Cycle lengths of polyAT were longer than during persistent and induced atrial fibrillation. Afterdepolarizations preceded polyAT in 2 patients. The electrical restitution curve was shifted to longer APD in LQTS patients and to even longer APD in LQTS patients with polyAT. Conclusion: This group of LQTS patients has altered atrial electrophysiology: action potentials are prolonged, and polyAT occurs. PolyAT appears to be a specific arrhythmia of LQTS reminiscent of an atrial form of “torsades de pointes.”(J Cardiovasc Electrophysiol, Vol. 14, pp ***‐***, October 2003)
Spatiotemporal Correlation Between Phase Singularities and Wavebreaks During Ventricular Fibrillation
Authors: LIU YEN‐BIN , PETER ANISH , LAMP SCOTT T. , WEISS JAMES N. , CHEN PENG‐SHENG , LIN SHIEN‐FONG 
Published: October 2003

Introduction:Phase maps and the detection of phase singularities (PSs) have become a well‐developed method for characterizing the organization of ventricular fibrillation (VF). How precisely PS colocalizes with wavebreak (WB) during VF, however, is unknown.Methods and Results:We performed optical mapping of 27 episodes of VF in nine Langendorff‐perfused rabbit hearts. A WB is a point where the activation wavefront and the repolarization waveback meet. A PS is a site where its phase is ambiguous and its neighboring pixels exhibit a continuous phase progression from−πto+π. The correlation coefficient between the number of WBs and PSs was0.78 ± 0.09for each heart and 0.81 for all VF episodes(P < 0.001), indicating a significant temporal correlation. We then superimposed the WBs and PSs for every 100 frames of each episode. These maps showed a high degree of spatial colocalization. To quantify spatial colocalization, the spatial shifts between the cumulative maps of WBs and PSs in corresponding frames were calculated by automatic alignment to obtain maximum overlap between these two maps. The spatial shifts were0.04 ± 0.31 mmon the x‐axis and0.06 ± 0.27 mmon the y‐axis over a20 × 20 mm2mapped field, indicating highly significant spatial correlation.Conclusion:Phase mapping provides a convenient and robust approach to quantitatively describe wave propagation and organization during VF. The close spatiotemporal correlation between PSs and WBs establishes that PSs are a valid alternate representation of WB during VF and further validated the use of phase mapping in the study of VF dynamics.(J Cardiovasc Electrophysiol, Vol. 14, pp. 1103‐1109, October 2003)