bluuebunny/crossref_metadata_2025 huggingface dataset:
A forkhead transcription factor FKHR up‐regulates lipoprotein lipase expression in skeletal muscle
Authors: Kamei Yasutomi , Mizukami Junko , Miura Shinji , Suzuki Miki , Takahashi Nobuyuki , Kawada Teruo , Taniguchi Tomoyasu , Ezaki Osamu
Published: March 2003

Lipoprotein lipase (LPL) plays a role in lipid usage in skeletal muscle by hydrolyzing plasma triglycerides into fatty acids, which are further utilized for β‐oxidation. Lipid usage is stimulated during fasting, diabetes mellitus and exercise, concomitant with enhanced LPL expression in skeletal muscle. Here we show that the forkhead type transcription factor FKHR is strongly induced in skeletal muscle in fasting mice, in mice with streptozotocin‐induced diabetes and in mice after treadmill running. Ectopic expression of FKHR enhanced LPL gene expression in C2C12 muscle cells in culture. These results implicate FKHR as an important modulator of lipid metabolism in skeletal muscle.
An externally fixed femoral fracture model for mice
Authors: Cheung Kenneth M. C. , Kaluarachi Kumara , Andrew Glynne , Lu William , Chan Danny , Cheah Kathryn S. E.
Published: March 2003

Transgenic and knockout mouse models can be used to help understand the molecular mechanisms of fracture repair. This study examines the feasibility of applying an external fixator to the mouse femur as one model for studying fracture repair. The external fixator consisted of two aluminum blocks connected by two rods. Four pins are used to connect the blocks to the bone. Mechanical characterization of the fixators was carried out prior to their use. Sixty‐two wild type mice with bilateral femoral fractures were created using an open technique and fixed using the fixator. The progress of fracture healing was monitored radiologically before sacrifice and by mechanical testing and histology after sacrifice. Initially four mice died intraoperatively from excessive blood loss, the intraoperative mortality was subsequently reduced by subcutaneous saline infusion. The bone healed between 14 and 21 days after fracture and remodeled by 60 days. Both radiological and mechanical assessments showed a steady progression of bone healing. Histology demonstrated callus and endochondral bone formation. This study demonstrated that it is possible to create a mouse femoral fracture model stabilized by external fixation and will provide an additional model to the understanding of fracture healing in transgenic and knockout mice. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Recombinant osteogenic protein‐1 upregulates extracellular matrix metabolism by rabbit annulus fibrosus and nucleus pulposus cells cultured in alginate beads
Authors: Masuda K. , Takegami K. , An H. , Kumano F. , Chiba K. , Andersson G. B. J. , Schmid T. , Thonar E.
Published: March 2003

This study was performed to determine if recombinant human osteogenic protein‐1 (rhOP‐1) is effective in promoting matrix synthesis and matrix formation by rabbit nucleus pulposus (NP) and annulus fibrosus (AF) cells cultured in alginate beads. The effects of culturing the cells in the presence of various concentrations of rhOP‐1 were assessed by measuring changes in cell proliferation, proteoglycan (PG) and collagen synthesis and mRNA expression, and in the matrix contents of PG and collagen, as indicators of matrix accumulation. At high concentrations, rhOP‐1 had a moderate mitogenic effect on both NP and AF cells. It also stimulated the synthesis of PG and collagen in a dose‐dependent manner: this was associated with a corresponding increase in the expression of mRNA for aggrecan core protein and collagen type II. The stimulatory effect of rhOP‐1 on PG synthesis was more pronounced than that on collagen synthesis. Continuous treatment with rhOP‐1 led to an increase in the total DNA, PG and collagen contents in both NP and AF cultures. The results presented here provide evidence of the ability of rhOP‐1 to stimulate the metabolism of both rabbit AF and NP cells cultured in alginate beads. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Regulatory role of E‐NTPase/NTPDase in fat/CD36‐mediated fatty acid uptake
Authors: Kannan Subburaj
Published: March 2003

Fatty acid translocase (FAT)/CD36‐mediated long‐chain fatty acid uptake in human umbilical vessel endothelial cells is associated with as yet uncharacterized translocase activity. The molecular mechanism of its function is not yet understood. Numerous attempts to purify rat cardiac sarcolemmal E‐NTPase (an integral membrane protein also referred to as ecto‐Ca2+/Mg2+ATPase) have revealed a complete amino acid sequence identity for FAT/CD36 protein. The most striking observation is that purified CD36 from human platelets shows significant E‐NTPase activity. In view of recent progress in understanding CD36 functional properties, an attempt is made in this article to illustrate the point that association of E‐NTPase (possibly extracellular Ca2+/Mg2+nucleotide triphosphate diphosphohydrolase) activity with CD36 may be of potential functional significance.
Sequence of a conserved region of a new sea urchin homeobox gene from the NKfamily
Authors: Smolenicka Zuzana , Pani Filippo , Hwang Kae‐Jung , Gruschus James M , Ferretti James A
Published: March 2003

The partial sequence of a novel homeobox‐containing gene from Paracentrotus lividus is described. Both cDNA and genomic DNA were screened using probes from the vnd/NK‐2 homeobox gene found in Drosophila melanogaster. The new DNA sequence found in P. lividus encodes a protein fragment that is closely related to the NK family of homeodomain transcriptional regulators originally discovered in the fruit fly. This study thus represents the first finding of a homeobox gene from the NK family in sea urchin. The DNA that was sequenced includes the most highly conserved region of the NK genes and contains the 180 base pair homeobox (i.e. the DNA segment that encodes the homeodomain), the NK‐2 box that encodes the NK‐2‐specific domain (NK‐2 SD), and the acidic box that encodes an acidic domain, but which is found only in a limited subset of the NK genes. In this deduced sequence, the 60 amino acid residue homeodomain contains tyrosine in position 54 and leucine in position 7, which implies that the protein will bind to an unusual sequence of DNA that contains 5′‐CAAGTG‐3′ as its core. The presence of tyrosine in position 54 identifies the gene as a member of the NK‐2 class of homeobox genes. Positions 37 and 56 of the homeodomain contain isoleucine and leucine, respectively, which is the first finding in the NK family of homeodomains of these particular amino acid residues in those positions. The presence of the NK‐2 box is consistent with identification of the gene as a member of the NK‐2 class, and suggests an important role for the C‐terminal portion of the protein in transcriptional activation. The sequence homology of the NK‐2 box and the spacing between it and the homeobox further suggest that this gene is a member of the NKx‐2.2 subclass, whose genes typically are expressed in brain and play a role in axonal guidance, and whose full lengths often are of the order of 900 bases. Homologous NK genes have been found in such diverse invertebrate and vertebrate species, such as Amphioxus sp., Xenopus sp., Caenorhabditis elegans, zebra fish, chicken, hamster, mouse and humans. The finding of this new gene together with sequence comparisons suggests possible evolutionary relationships between sea urchins and vertebrates in the developmental pathways of their body plans.
Altered calcium transient and development of hypertrophy in β2‐adrenoceptor overexpressing mice with and without pressure overload
Authors: Schwarz Bettina , Percy Elodie , Gao Xiao‐Ming , Dart Anthony M. , Richardt Gert , Du Xiao‐Jun
Published: March 2003

Transgenic (TG) mice with cardiac specific 200‐fold overexpression of β2‐adrenoceptors (β2‐AR) have a facilitated development of heart failure following thoracic aortic constriction (TAC). We have studied the alterations of intracellular Ca2+ transients and myocyte size in wild‐type (WT) and TG mice after TAC. Cardiomyocytes were isolated from mice 9 weeks after TAC or sham operation, and incubated with Fura 2/AM. The Ca2+ transients were determined by Spex dual wavelength Spectrometer during electrical stimulation. The cell size was also determined planimetrically. Cells of sham operated TG mice displayed higher systolic Ca2+ amplitude than respective WT group (ΔF340/F380 ratio: 1.05±0.08 vs. 0.63±0.05; P<0.01), a finding in keeping with enhanced ventricular contractility in the TG mice. However, hypertrophied and failing myocytes of TG animals showed a fall in Ca2+ transients from sham‐operated control levels and there was no difference between TG and WT groups following TAC. In sham‐operated groups, the cell size of TG mice was significantly bigger than in WT animals (3212±139 vs. 2605±162 μm2; P<0.05). The cell size increased to a similar extent in both groups after TAC (4715±216 vs. 5027±365 μm2, P=n.s.). In summary, hypertrophy of cardiomyocytes was present in β2‐AR TG mice under baseline conditions. A further hypertrophy occurred during pressure overload to an extent similar to that in WT animals. However, the increased intracellular Ca2+ transient, seen in sham‐operated TG mice, was no longer detectable following development of severe hypertrophy and heart failure. These findings provide explanation on the lack of hemodynamic benefit in β2‐AR TG mice subjected to pressure overload.
Hypoxia, angiotensin‐II, and norepinephrine mediated apoptosis is stimulus specific in canine failed cardiomyocytes: a role for p38 MAPK, Fas‐L and cyclin D1
Authors: Sharov Victor G. , Todor Anastassia , Suzuki George , Morita Hideaki , Tanhehco Elaine J. , Sabbah Hani N.
Published: March 2003

Background:

Apoptosis may contribute to the myocardial dysfunction associated with heart failure (HF). Activation of the p38 MAPK cascade can induce apoptosis in non‐cardiac cells through increased expression of Fas‐L, or through decreased expression of cyclin D1.

Aims:

We tested the hypothesis that hypoxia (HX), angiotensin‐II (A‐II) and norepinephrine (NEPI) can mediate apoptosis by activating p38 MAPK, and thus initiating stimulus specific changes in Fas‐L and cyclin D1 expression in failing cardiomyocytes.

Methods and results:

Cardiomyocytes isolated from ten dogs with HF induced by coronary microembolizations were subjected to HX or A‐II or NEPI with and without a p38 MAPK inhibitor (SB 203580). TUNEL staining for DNA fragmentation and Western blots for p38 MAPK, Fas‐L and cyclin D1 detection were performed. HX‐induced apoptosis was associated with increased Fas‐L expression, A‐II‐induced apoptosis was associated with increased Fas‐L and decreased cyclin D1 expression, and NEPI‐induced apoptosis was associated with decreased cyclin D1 expression. Inhibition of p38 MAPK activity attenuated stress‐induced apoptosis in all experiments and reversed changes in Fas‐L and cyclin D1 expression.

Conclusions:

HX, A‐II and NEPI mediate apoptosis in failing cardiomyocytes via different effects on Fas‐L and cyclin D1 expression. Inhibition of p38 MAPK reversed these effects, suggesting that apoptosis induced by HX, A‐II and NEPI involves activation of p38 MAPK upstream from Fas‐L and cyclin D1.
Lamivudine after hepatitis B immune globulin is effective in preventing hepatitis B recurrence after liver transplantation
Authors: Dodson Forrest S. , de Vera Michael E. , Bonham Andrew C. , Geller David A. , Rakela Jorge , Fung John J.
Published: March 2003

The prevention of recurrent hepatitis B virus (HBV) infection after orthotopic liver transplantation (OLT) with hepatitis B immunoglobulin (HBIG) is expensive and requires indefinite parenteral administration. Lamivudine is a nucleoside analogue capable of inhibiting HBV replication. The aim of this study is to determine the efficacy of lamivudine in the prevention of recurrent HBV infection after a course of HBIG in patients who were hepatitis B surface antigen (HBsAg) positive and hepatitis Be antigen (HBeAg) negative before OLT. Patients at high risk for recurrent HBV infection (HBeAg positive and HBV DNA positive) were excluded. Thirty HBsAg-positive, HBeAg-negative patients underwent OLT from January 1993 to June 1997. All 30 patients were administered HBIG after OLT and, after 2 years, were given the option of continuing with HBIG or switching to lamivudine. Five patients were excluded: 3 patients were lost to follow-up and 2 patients died of technical complications. Three patients terminated HBIG therapy at 8, 24, and 29 months after OLT, and reinfection with HBV occurred in 1 patient. Six patients elected to continue HBIG therapy for life; 1 patient died of melanoma and the remaining 5 patients are HBsAg negative, with an average follow-up of 73 months. Sixteen patients were converted to lamivudine after a course of HBIG, and all 16 patients are HBsAg negative, with an average follow-up of 51 months after OLT. Five patients have been on lamivudine monotherapy for more than 24 months. These results suggest that lamivudine administered after a posttransplantation course of HBIG can effectively prevent the recurrence of HBV infection in patients who are HBsAg positive and HBeAg negative before OLT.
Acceptance of an ABO-incompatible mismatched (AB+ to O+) liver allograft with the use of daclizumab and mycophenolate mofetil
Authors: Fang Christopher W. , Saltzman John , Rososhansky Sarah , Szabo Gyongi , Heard Stephen O. , Banner Barbara , Chari Ravi , Katz Eliezer
Published: March 2003

Liver allograft survival rates of 50% to 60% are reported in blood group A, group B, group O (ABO)-incompatible mismatched grafts even when aggressive immunosuppressive protocols, including plasmapheresis, OKT3, cyclophosphamide, cyclosporine, prostaglandin E1, and steroids, are used. A 59-year-old woman, blood type O+, required emergency retransplantation posttransplantation day 2 because of primary nonfunction of the liver allograft. A blood type AB+ allograft was used. Induction immunosuppressive therapy included tacrolimus, mycophenolate mofetil, OKT3 (muromonab-CD3), steroids, and prostaglandin E1. In addition, plasmapheresis was performed daily for 9 days. OKT3 and prostaglandin E1 were also discontinued postoperative day 9. Biopsy-proven acute cellular rejection was diagnosed postoperative day 12 and was treated with double-dose OKT3 (10 mg) for another 6 days. On the day OKT3 was discontinued, daclizumab, 60 mg, was administered intravenously. This dose was repeated every 2 weeks for a total of 5 doses. At 1-year follow-up, the patient is doing very well with normal liver function. We are unaware of previous reports of the use of daclizumab and mycophenolate mofetil as part of an immunosuppressive protocol aimed to induce acceptance of ABO-incompatible mismatched liver allografts. Based on our experience with this case, it seems that mycophenolate mofetil is an adequate replacement for cyclophosphamide. We also believe daclizumab provided adequate protection at a critical time. Further experience with both these drugs is required to establish their role in ABO-incompatible mismatched liver allografts.
Adaptation of the mayo primary biliary cirrhosis natural history model for application in liver transplant candidates
Authors: Kim Ray W. , Wiesner Russell H. , Poterucha John J. , Therneau Terry M. , Benson Joanne T. , Krom Ruud A.F. , Dickson Rolland E.
Published: March 2003

The Mayo natural history model has been used widely as a tool to estimate prognosis in patients with primary biliary cirrhosis (PBC), particularly liver transplant candidates. We present an abbreviated model in which a tabular method is used to approximate the risk score, which may be incorporated in the minimal listing criteria for liver transplant candidates. Data used in the development and validation of the original Mayo model were derived from 418 patients with well-characterized PBC. To construct an abbreviated risk score in a format similar to that of Child-Turcotte-Pugh score, 1 to 3 cut-off criteria were determined for each variable, namely age (0 point for <38, 1 for 38 to 62 and 2 for ≥63 years), bilirubin (0 point for <1, 1 for 1 to 1.7, 2 for 1.7 to 6.4, and 3 for >6.4 mg/dL), albumin (0 point for >4.1, 1 for 2.8 to 4.1, and 2 for <2.8 g/dL), prothrombin time (1 point for normal and 2 for prolonged) and edema (0 point for absent and 1 for present). The intervals between these criteria were chosen in a way to enable a meaningful classification of patients according to their risk for death. This score is highly correlated with the original risk score (r = 0.93; P < .01). The Kaplan-Meier estimate at 1 year was 90.6% in patients with a score of 6. The abbreviated risk score is a convenient method to quickly estimate the risk score in patients with PBC. An abbreviated score of 6 may be consistent with the current minimal listing criteria in liver transplant candidates.
Endotoxins and cytokines during liver transplantation: Changes in plasma levels and effects on clinical outcome
Authors: Maring John K. , Klompmaker Ids J. , Zwaveling Jan H. , van der Meer Jan , Limburg Pieter C. , Slooff Maarten J.H.
Published: March 2003

Endotoxins, tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and IL-6 are believed to have a key role in liver transplantation. The origin and course of these factors is not completely known. In this prospective study of 40 patients, we sought more understanding of the relations between these factors and their effects on clinical outcome by sampling at different sites. Endotoxemia was only present in 20% of the patients. In 75% of these patients, it was present during the anhepatic phase and quickly resolved after reperfusion. Endotoxemia was not related to a clinical adverse event. TNF-α was released from the graft after reperfusion, and initial levels after reperfusion were related to predonation levels in the donor. Only levels of TNF-α in the recipient before transplantation were found to be predictive of postoperative complications. We conclude that monitoring endotoxins and these cytokines is of very limited value in predicting outcome.
Essential role of Ca2+/Calmodulin in Early Endosome Antigen-1 Localization
Authors: Lawe Deirdre C. , Sitouah Nachida , Hayes Susan , Chawla Anil , Virbasius Joseph V. , Tuft Richard , Fogarty Kevin , Lifshitz Lawrence , Lambright David , Corvera Silvia
Published: March 2003

Ca2+is an essential requirement in membrane fusion, acting through binding proteins such as calmodulin (CaM). Ca2+/CaM is required for early endosome fusion in vitro, however, the molecular basis for this requirement is unknown. An additional requirement for endosome fusion is the protein Early Endosome Antigen 1 (EEA1), and its recruitment to the endosome depends on phosphatidylinositol 3-phosphate [PI(3)P] and the Rab5 GTPase. Herein, we demonstrate that inhibition of Ca2+/CaM, by using either chemical inhibitors or specific antibodies directed to CaM, results in a profound inhibition of EEA1 binding to endosomal membranes both in live cells and in vitro. The concentration of Ca2+/CaM inhibitors required for a full dissociation of EEA1 from endosomal membranes had no effect on the activity of phosphatidylinositol 3-kinases or on endogenous levels of PI(3)P. However, the interaction of EEA1 with liposomes containing PI(3)P was decreased by Ca2+/CaM inhibitors. Thus, Ca2+/CaM seems to be required for the stable interaction of EEA1 with endosomal PI(3)P, perhaps by directly or indirectly stabilizing the quaternary organization of the C-terminal FYVE domain of EEA1. This requirement is likely to underlie at least in part the essential role of Ca2+/CaM in endosome fusion.
Calponin Repeats Regulate Actin Filament Stability and Formation of Podosomes in Smooth Muscle Cells
Authors: Gimona Mario , Kaverina Irina , Resch Guenter P. , Vignal Emmanuel , Burgstaller Gerald
Published: March 2003

Phorbol ester induces actin cytoskeleton rearrangements in cultured vascular smooth muscle cells. Calponin and SM22 α are major components of differentiated smooth muscle and potential regulators of actin cytoskeleton interactions. Here we show that actin fibers decorated with h1 CaP remain stable, whereas SM22 α-decorated actin bundles undergo rapid reorganization into podosomes within 30 min of PDBu exposure. Ectopic expression of GFP α-actinin had no effect on the stability of the actin cytoskeleton and α-actinin was transported rapidly into PDBu-induced podosomes. Our results demonstrate the involvement of CaP and SM22 α in coordinating the balance between stabilization and dynamics of the actin cytoskeleton in mammalian smooth muscle. We provide evidence for the existence of two functionally distinct actin filament populations and introduce a molecular mechanism for the stabilization of the actin cytoskeleton by the unique actin-binding interface formed by calponin family-specific CLIK23repeats.
The Hippocampal Laminin Matrix Is Dynamic and Critical for Neuronal Survival
Authors: Chen Zu-Lin , Indyk Justin A. , Strickland Sidney
Published: March 2003

Laminins are extracellular matrix proteins that participate in neuronal development, survival, and regeneration. During excitotoxin challenge in the mouse hippocampus, neuron interaction with laminin-10 (α5,β1,γ1) protects against neuronal death. To investigate how laminin is involved in neuronal viability, we infused laminin-1 (α1,β1,γ1) into the mouse hippocampus. This infusion specifically disrupted the endogenous laminin layer. This disruption was at least partially due to the interaction of the laminin-1 γ1 chain with endogenous laminin-10, because infusion of anti-laminin γ1 antibody had the same effect. The disruption of the laminin layer by laminin-1 1) did not require the intact protein because infusion of plasmin-digested laminin-1 gave similar results; 2) was posttranscriptional, because there was no effect on laminin mRNA expression; and 3) occurred in both tPA–/–and plasminogen–/–mice, indicating that increased plasmin activity was not responsible. Finally, although tPA–/–mice are normally resistant to excitotoxin-induced neurodegeneration, disruption of the endogenous laminin layer by laminin-1 or anti-laminin γ1 antibody renders the tPA–/–hippocampal neurons sensitive to kainate. These results demonstrate that neuron interactions with the deposited matrix are not necessarily recapitulated by interactions with soluble components and that the laminin matrix is a dynamic structure amenable to modification by exogenous molecules.
5-Oxatricyclo[5.1.0.01,3]octan-4-one, containing an enantiomorph and a racemate and not two polymorphs, is another example of a composite crystal
Authors: Herbstein Frank H.
Published: March 2003

This new example of a composite crystal adds to the small number previously reported among inorganic and molecular materials. Revision of the nomenclature used allows more fruitful comparison with the precedents.
Micro-Thermal Field-Flow Fractionation of Colloidal Particles: Effect of Temperature on Retention and Relaxation Processes
Authors: Janča Josef
Published: March 2003

An important decrease in the heat flux across the micro-thermal field-flow fractionation (micro-TFFF) channel compared with the standard size channel allowed to control independently the temperatures of the cold and hot walls and to study the behaviour of colloidal particles within an extended temperature range. The only limitation was imposed by the freezing and boiling points of the carrier liquid. The retention and the relaxation processes were found to be influenced by temperature. A decrease in the viscosity of the carrier liquid with increasing temperature results in an increase in the diffusion coefficient of the retained species. Consequently, the relaxation processes associated with the establishment of the steady-state concentration distribution are accelerated, the time to reach the steady state decreases with increasing temperature, and the retention ratio of moderately retained particles decreases to reach a minimum value. The fractograms of colloidal samples of narrow particle size distribution (PSD) obtained at lowest temperatures can exhibit two peaks; the first corresponding to the unrelaxed particles eluted even at higher than the average velocity of the carrier liquid and the second one corresponding to the particles retained less compared with the zone eluted at a steady state from the very beginning. The further increase in temperature above that at which the retention ratio reaches the mentioned minimum produces inversion of the retention ratio, i.e. its increase. The peak corresponding to the unrelaxed part of the particles progressively disappears with increasing temperature. If the flow of the carrier liquid is stopped immediately after the injection of the sample for a time to reach a steady-state concentration distribution of the particles across the channel and restarted after that period, the retention ratio does not exhibit a pronounced minimum. On the other hand, the width of the zone generally decreases with increasing temperature but less if the stop-flow procedure is applied. These findings confirm that the retention ratio is influenced by temperature in agreement with the theoretical prediction. A practical conclusion is that higher resolution and reduced time of the separation can be achieved at higher temperatures of the accumulation wall. The micro-TFFF thus becomes a highly competitive method of separation and determination of the PSD of colloidal particles.
Preparation of E-Secolupane Acids and Lactones
Authors: Tišlerová Iva , Klinotová Eva , Klinot Jiří , Sejbal Jan , Rejzek Martin , Hilgard Stanislav
Published: March 2003

Anhydrides of 3β,28-diacetoxy-21,22-secolup-18-ene-21,22-dioic acid (1) and (19R)-3β,28-diacetoxy-18β,19-epoxy-21,22-secolupane-21,22-dioic acid (11) undergo alkaline hydrolysis yielding the corresponding dicarboxylic acids. Depending on reaction conditions, these acids are further transformed yielding various lactones, liberating C-28 hydroxymethyl group, or undergoing decarboxylation leading to nor derivatives. This method has been used to prepare a diverse series of E-secolupane derivatives including lactonoacids (e.g. 2 and 15), lactones (4, 16 and 17), 28-nor derivatives (3 and 6) and 21,28-dinor derivatives (12 and 13). Derivatives of (19R)-3β,28-dihydroxy-18β,19-epoxy-21,22-secolupane-21,22-dioic acid 21,28-lactone (15c), bearing a free carboxylic group, are labile and can only be isolated as the corresponding dilactones 17. The C-22 carboxylic group forms a β-lactone by a nucleophilic α-directed attack on the C-18 epoxide ring carbon atom resulting in (19R)-3β,19-dihydroxy-21,22-secolupane-21,28:22,18α-dilactone (17b) and related derivatives. The structure and stereochemistry of the compounds discussed in this contribution were derived from IR, MS, 1H and 13C NMR spectra (1D and 2D COSY, TOCSY, NOESY, HSQC, HMBC). Using these NMR techniques and measuring the solvent influence on the IR carbonyl stretching frequencies of the dilactones 17, an equilibrium between the two E-ring conformations was shown to exist.
Cyclization of Semicarbazide Derivatives of 3-Methyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazole-4-acetic Acid
Authors: Dobosz Maria , Pitucha Monika , Dybala Izabela , Kozioł Anna E.
Published: March 2003

By the reaction of hydrazide of 3-methyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazole-4-acetic acid (1) with isocyanates, 3-methyl-5-thioxo-4,5-dihydro-1H-1,2,4-triazole-4-acetosemicarbazide derivatives 2 were obtained. Cyclization of these compounds in the presence of 2% NaOH led to the formation of 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives 3, which was confirmed by X-ray analysis of 3b.
Arsenate and Chromate Removal with Cationic Surfactant-Loaded and Cation-Exchanged Clinoptilolite-Rich Tuff vs Montmorillonite
Authors: Chmielewská Eva , Jesenák Karol , Gáplovská Katarína
Published: March 2003

Using a laboratory set-up, sorption of chromate and arsenate from aqueous solutions with the octadecylammonium acetate (ODA)-modified clinoptilolite was examined. In the experiments, a natural montmorillonite was compared with organically, i.e. surfactant-loaded clinoptilolite and with some inorganically substituted (Ag, Pb)-monoforms. The arrangements of the surface-attached ODA chains have been an important factor for the difference in the adsorption states of the guest species (oxyanions). A novel nanostructure inorganic-organic composite prepared has been investigated using SEM, thermogravimetry, UV-VIS diffuse reflectance and powder XRD spectral analytical methods. Finally, adsorption isotherms for the system studied have been measured. An approach for regeneration of exhausted surfactant-immobilized clinoptilolite with inorganic salt solutions under dynamic regime has been proposed.
FRACTAL TWO-LEVEL FINITE ELEMENT MESH FOR ACOUSTIC SCATTERING PROBLEMS
Authors: LEUNG A. Y. T. , WU G. R. , ZHONG W. F.
Published: March 2003

The problems of acoustic waves scattered by scatterer immersed in unbounded domain is an essential ingredient in the study of acoustic-structure interaction. In this paper the problems of acoustic scattering in an infinite exterior region are investigated by using a fractal two-level finite element mesh with self-similar layers in the media which encloses the conventional finite element mesh for the cavity. The similarity ratio is bigger than one so that the fractal mesh extends to infinity. Because of the self-similarity, the equivalent stiffness (mass) matrix of one layer is proportional to the others. By means of the Hankel functions automatically satisfying Sommerfeld's radiation conditions at infinity, the different unknown nodal pressures on different layers are transformed to some common unknowns of the Hankel coefficients. The set of infinite number of unknowns of nodal pressure is reduced to the set of finite number of Hankel's coefficients. All layers have the same matrix dimension after the transformation and the respective matrices of each layer are summed. Due to the proportionality, the infinite number of layers can be summed in closed form as the entries of each matrix are in geometric series. That is, processing one layer is enough to virtually represent a set of infinite number of layers covering an infinity domain. No new elements are created. Numerical examples show that this method is efficient and accurate in solving unbounded acoustic problems.
NUMERICAL STUDY OF SOUND RADIATION BY AXISYMMETRIC VORTEX RINGS
Authors: RIVOALEN ELIE , HUBERSON SERGE , KNIO OMAR M.
Published: March 2003

The sound production by vortex rings is investigated by means of an axisymmetric vortex particle method. The predictions are first calibrated by analyzing the noise generated by steady vortex rings that are described by the analytical solutions of Fraenkel and Norbury. The noise produced by isolated vortex rings for both nominally steady and unsteady cores is then analyzed. For nominally steady cores, computed results indicate that the efficiency of sound radiation decreases as the slenderness parameter is reduced, and the acoustic signals reveal a dominant period that is approximately half the eddy turnover time. For unsteady cores, the amplitude of the radiated sound is substantially higher than that of similar steady rings. When the initial core vorticity distribution is nonuniform, complex internal motion may also occur within the core which is also reflected in the corresponding far-field acoustic signal. Finally, the effect of vortex stretching is analyzed based on computations of two coaxial corotating vortex rings.
VIBRATIONAL ANALYSIS OF SHIPS WITH COUPLED FINITE AND BOUNDARY ELEMENTS
Authors: CABOS CHRISTIAN , IHLENBURG FRANK
Published: March 2003

The vibrational analysis of ships involves the solution of a coupled fluid-structure interaction problem in order to simulate the inertia response of the water to the structural vibrations. The paper describes a coupled FE-BE procedure for the computational solution of this problem. Regarding the structural equations, special emphasis is put on the modeling of damping. Various models of damping, in particular local damping, are discussed and implemented into the FE-model of the ship structure. The computational results are compared to data from large-scale measurements.
UPCONVERSION OF INTERGROUP HOT-CARRIER NOISE IN SEMICONDUCTORS OPERATING UNDER PERIODIC LARGE-SIGNAL CONDITIONS
Authors: SHIKTOROV PAVEL , STARIKOV EVGENIJ , GRUŽINSKIS VIKTORAS , PEREZ SUSANA , GONZALEZ TOMAS , REGGIANI LINO , VARANI LUCA , VAISSIERE JEAN-CLAUDE
Published: March 2003

By means of Monte Carlo simulations of carrier transport in bulk semiconductors operating under periodic large-signal regime, we show the existence of upconversion of low-frequency hot-carrier noise associated with velocity fluctuations into a high-frequency region centered around the fundamental frequency of the large-signal. It is found that the upconverted noise corresponds to long-time fluctuations of relative populations of two groups of carriers characterized by different dynamical properties in momentum space. The appearance of the upconversion process is related to kinks of the static velocity-field characteristic when the dynamics of carrier motion in momentum space undergoes drastic changes.
Protein-Lipid Interplay in Fusion and Fission of Biological Membranes
Authors: Chernomordik Leonid V. , Kozlov Michael M.
Published: March 2003

▪ Abstract  Disparate biological processes involve fusion of two membranes into one and fission of one membrane into two. To formulate the possible job description for the proteins that mediate remodeling of biological membranes, we analyze the energy price of disruption and bending of membrane lipid bilayers at the different stages of bilayer fusion. The phenomenology and the pathways of the well-characterized reactions of biological remodeling, such as fusion mediated by influenza hemagglutinin, are compared with those studied for protein-free bilayers. We briefly consider some proteins involved in fusion and fission, and the dependence of remodeling on the lipid composition of the membranes. The specific hypothetical mechanisms by which the proteins can lower the energy price of the bilayer rearrangement are discussed in light of the experimental data and the requirements imposed by the elastic properties of the bilayer.
Proteomics
Authors: Zhu Heng , Bilgin Metin , Snyder Michael
Published: March 2003

▪ Abstract  Fueled by ever-growing DNA sequence information, proteomics-the large scale analysis of proteins-has become one of the most important disciplines for characterizing gene function, for building functional linkages between protein molecules, and for providing insight into the mechanisms of biological processes in a high-throughput mode. It is now possible to examine the expression of more than 1000 proteins using mass spectrometry technology coupled with various separation methods. High-throughput yeast two-hybrid approaches and analysis of protein complexes using affinity tag purification have yielded valuable protein-protein interaction maps. Large-scale protein tagging and subcellular localization projects have provided considerable information about protein function. Finally, recent developments in protein microarray technology provide a versatile tool to study protein-protein, protein-nucleic acid, protein-lipid, enzyme-substrate, and protein-drug interactions. Other types of microarrays, though not fully developed, also show great potential in diagnostics, protein profiling, and drug identification and validation. This review discusses high-throughput technologies for proteome analysis and their applications. Also discussed are the approaches used for the integrated analysis of the voluminous sets of data generated by proteome analysis conducted on a global scale.
Dynamics of Cell Surface Molecules During T Cell Recognition
Authors: Davis Mark M. , Krogsgaard Michelle , Huppa Johannes B. , Sumen Cenk , Purbhoo Marco A. , Irvine Darrell J. , Wu Lawren C. , Ehrlich Lauren
Published: March 2003

▪ Abstract  Recognition of foreign antigens by T lymphocytes is a very important component of vertebrate immunity—vital to the clearance of pathogenic organisms and particular viruses and necessary, indirectly, for the production of high affinity antibodies. T cell recognition is mediated by the systematic scanning of cell surfaces by T cells, which collectively express many antigen receptors. When the appropriate antigenic peptide bound to a molecule of the major histocompatibility complex is found—even in minute quantities—a series of elaborate cell-surface molecule and internal rearrangements take place. The sequence of events and the development of techniques required to observe these events have significantly enhanced our understanding of T cell recognition and may find application in other systems of transient cell:cell interactions as well.
The Dynamics of Chromosome Organization and Gene Regulation
Authors: Spector David L.
Published: March 2003

▪ Abstract  With the sequence of the human genome now complete, studies must focus on how the genome is functionally organized within the confines of the cell nucleus and the dynamic interplay between the genome and its regulatory factors to effectively control gene expression and silencing. In this review I describe our current state of knowledge with regard to the organization of chromosomes within the nucleus and the positioning of active versus inactive genes. In addition, I discuss studies on the dynamics of chromosomes and specific genetic loci within living cells and its relationship to gene activity and the cell cycle. Furthermore, our current understanding of the distribution and dynamics of RNA polymerase II transcription factors is discussed in relation to chromosomal loci and other nuclear domains.
Temporal and Spatial Regulation in Prokaryotic Cell Cycle Progression and Development
Authors: Ryan Kathleen R. , Shapiro Lucy
Published: March 2003

▪ Abstract  Bacteria exhibit a high degree of intracellular organization, both in the timing of essential processes and in the placement of the chromosome, the division site, and individual structural and regulatory proteins. We examine the temporal and spatial regulation of the Caulobacter cell cycle, bacterial chromosome segregation and cytokinesis, and Bacillus subtilis sporulation. Mechanisms that control timing of cell cycle and developmental events include transcriptional cascades, regulated phosphorylation and proteolysis of signal transduction proteins, transient genetic asymmetry, and intercellular communication. Surprisingly, many signal transduction proteins are dynamically localized to specific subcellular addresses during the cell division cycle and sporulation, and proper localization is essential for their function. The Min proteins that govern division site selection in Escherichia coli may be the first example of a system that generates positional information de novo.
The heme-heme oxygenase system: a molecular switch in wound healing
Authors: Wagener Frank A. D. T. G. , van Beurden Hugo E. , von den Hoff Johannes W. , Adema Gosse J. , Figdor Carl G.
Published: March 2003

When cells are injured they release their contents, resulting in a local accumulation of free heme proteins and heme. Here, we investigated the involvement of heme and its degrading enzyme heme oxygenase (HO) in the inflammatory process during wound healing. We observed that heme directly accumulates at the edges of the wound after inflicting a wound in the palate of Wistar rats. This coincided with an increased adhesion molecule expression and the recruitment of leukocytes. To prove that heme is responsible for the recruitment of leukocytes, heme was administered intradermally 24 hours prior to injury. A clear heme-induced influx of both macrophages and granulocytes was observed. When examining the HO isoforms, HO-1 and HO-2, we found that HO-2 was present in the entire submucosa. Surprisingly, we observed also that HO-1 is significantly expressed in the epithelium of both the mucosa and the skin of animals without wounds. On inflammation, HO-1 expression increased, particularly in infiltrating cells during the resolution phase of inflammation. Interestingly, we observed that heme-induced influx of leukocytes was highly elevated after pharmacologic inhibition of HO activity. These observations suggest that the heme-HO system is closely involved in the control of wound healing. Our results demonstrate that the local release of heme may be a physiologic trigger to start inflammatory processes, whereas HO-1 antagonizes inflammation by attenuating adhesive interactions and cellular infiltration. Moreover, the basal level of HO expression in the skin may serve as a first protective environment against acute oxidative and inflammatory insults.
Genetically targeted radiotherapy for multiple myeloma
Authors: Dingli David , Diaz Rosa Maria , Bergert Elizabeth R. , O'Connor Michael K. , Morris John C. , Russell Stephen J.
Published: March 2003

Multiple myeloma is a disseminated neoplasm of terminally differentiated plasma cells that is incurable with currently available therapies. Although the disease is radiosensitive, external beam radiation leads to significant toxicity due to sensitive end-organ damage. Thus, genetic approaches for therapy are required. We hypothesized that the incorporation of immunoglobulin promoter and enhancer elements in a self-inactivating (SIN) lentiviral vector should lead to specific and high-level transgene expression in myeloma cells. A SIN lentivector with enhanced green fluorescent protein (EGFP) expression under the control of a minimal immunoglobulin promoter as well as the Kappa light chain intronic and 3′ enhancers transduced myeloma cell lines with high efficiency (30%-90%). EGFP was expressed at a high level in myeloma cells but silent in all nonmyeloma cell lines tested compared with the cytomegalovirus (CMV) promoter/enhancer. Transduction of myeloma cells with the targeted vector coding for the human sodiumiodide symporter (hNIS) led to hNIS expression by these cells allowing them to concentrate radioiodine up to 18-fold compared with controls. Tumor xenografts in severe combined immunodeficiency mice expressing hNIS could be imaged using iodine-123 (123I) and shown to retain iodide for up to 48 hours. These tumor xenografts were completely eradicated by a single dose of the therapeutic isotope iodine-131 (131I) without evidence of recurrence up to 5 months after therapy. We conclude that lentivectors can be transcriptionally targeted for myeloma cells and the use of hNIS as a therapeutic gene for myeloma in combination with 131I needs further exploration.
Melphalan-mobilized blood stem cell components contain minimal clonotypic myeloma cell contamination
Authors: Zhou Ping , Zhang Yana , Martinez Carmen , Kalakonda Nagesh , Nimer Stephen D. , Comenzo Raymond L.
Published: March 2003

Optimal methods of stem cell mobilization in multiple myeloma are undefined, and contaminating clonotypic cells could contribute to disease recurrence. A phase 2 trial of intravenous melphalan (60 mg/m2) and granulocyte colony-stimulating factor (G-CSF) (10 μg/kg/d) for mobilization was performed. To enhance reliability, contamination was assessed with 2 sensitive methods, immunoglobulin light and heavy chain variable region patient-specific limiting-dilution polymerase chain reaction (PCR). We evaluated 29 stem cell components (SCCs) from 15 patients; for 9 SCCs, only VL PCR was used because of light chain disease or technical problems with VH primers. For 20 SCCs, VL and VH PCR results were highly correlated (r2 = 0.93, P < .01), with 35% (7 of 20) having identical estimates. VH PCR gave significantly higher estimates for 8—and VL PCR for 5—SCCs, supporting the utility of using 2 methods. Estimated clonotypic contamination per SCC was 0.0009% (range, 0%-0.1%) or 0.5 × 104 clonotypic cells per kilogram (range, 0-41.2 × 104/kg), and contamination correlated with CD34+ cells collected (r2 = 0.42, P < .01). Melphalan-mobilized SCCs contain minimal clonotypic contamination.
Transgenic delivery of VEGF to mouse skin leads to an inflammatory condition resembling human psoriasis
Authors: Xia Yu-Ping , Li Baosheng , Hylton Donna , Detmar Michael , Yancopoulos George D. , Rudge John S.
Published: March 2003

Gene therapy approaches involving vascular endothelial growth factor (VEGF) to promote therapeutic angiogenesis are under consideration for conditions ranging from ischemic heart disease to nonhealing skin ulcers. Here we make the surprising observation that the transgenic delivery of VEGF to the skin results in a profound inflammatory skin condition with many of the cellular and molecular features of psoriasis, including the characteristic vascular changes, epidermal alterations, and inflammatory infiltrates. Even longstanding psoriatic disease remains dependent on the transgenic VEGF in this model because it can be effectively reversed by the addition of VEGF Trap, a potent VEGF antagonist. Previous attempts to faithfully replicate the psoriatic phenotype through the transgenic delivery of epidermal keratinocyte growth factors or inflammatory mediators generated phenotypes with only partial resemblance to human psoriasis, leaving unanswered questions about the etiology of this disease. The ability of transgenic VEGF to induce a psoriasiform phenotype suggests a new etiology and treatment approach for this disease and further substantiates emerging concerns about possible proinflammatory adverse effects that might be associated with therapeutic attempts to deliver VEGF. (Blood. 2003;102:161-168)
Dual effects of macrophage inflammatory protein-1α on osteolysis and tumor burden in the murine 5TGM1 model of myeloma bone disease
Authors: Oyajobi Babatunde O. , Franchin Giovanni , Williams Paul J. , Pulkrabek Donna , Gupta Anjana , Munoz Steve , Grubbs Barry , Zhao Ming , Chen Di , Sherry Barbara , Mundy Gregory R.
Published: March 2003

Recent data have implicated macrophage inflammatory protein-1α (MIP-1α) in multiple myeloma (MM)-associated osteolysis. However, it is unclear whether the chemokine's effects are direct, to enhance osteolysis, or indirect and mediated through a reduction in tumor burden, or both. It is also unclear whether MIP-1α requires other factors such as receptor activator of nuclear factor-κB ligand (RANKL) for its effects on bone. In murine 5TGM1 (Radl) myeloma-bearing mice, administration of neutralizing anti-MIP-1α antibodies reduced tumor load assessed by monoclonal paraprotein titers, prevented splenomegaly, limited development of osteolytic lesions, and concomitantly reduced tumor growth in bone. To determine the effects of MIP-1α on bone in vivo, Chinese hamster ovary (CHO) cells secreting human MIP-1α (CHO/MIP-1α) were inoculated into athymic mice. Mice bearing intramuscular CHO/MIP-1α tumors developed lytic lesions at distant skeletal sites, which occurred earlier and were larger than those in mice with CHO/empty vector (EV) tumors. When experimental metastases were induced via intracardiac inoculation, mice bearing CHO/MIP-1α tumors developed hypercalcemia and significantly more osteolytic lesions than mice bearing CHO/EV tumors, with intramedullary CHO/MIP-1α tumors associated with significantly more tartrate-resistant acid phosphatase-positive (TRAP+) osteoclasts. Injection of recombinant MIP-1α over calvariae of normal mice evoked a striking increase in osteoclast formation, an effect dependent on RANK/RANKL signaling because MIP-1α had no effect in RANK-/- mice. Together, these results establish that MIP-1α is sufficient to induce MM-like destructive lesions in bone in vivo. Because, in the 5TGM1 model, blockade of osteoclastic resorption in other situations does not decrease tumor burden, we conclude that MIP-1α exerts a dual effect in myeloma, on osteoclasts, and tumor cells. (Blood. 2003;102:311-319)