bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of Mcl‐1 in mantle cell lymphoma is associated with high‐grade morphology, a high proliferative state, and p53 overexpression
Authors: Khoury Joseph D , Medeiros L Jeffrey , Rassidakis George Z , McDonnell Timothy J , Abruzzo Lynne V , Lai Raymond
Published: December 2002

Mantle cell lymphoma (MCL) is a distinct type of B‐cell non‐Hodgkin's lymphoma characterized by the t(11;14)(q13;q32) and cyclin D1 overexpression. Defects in apoptosis may contribute to pathogenesis. This study evaluated the expression of the anti‐apoptotic protein Mcl‐1 in two MCL cell lines and five frozen MCL tumours (four small‐cell, one blastoid/large‐cell) using western blot analysis. Mcl‐1 expression was also assessed in 36 formalin‐fixed, paraffin wax‐embedded MCL tumours (24 small‐cell, 12 blastoid/large‐cell) by immunohistochemistry. Western blot analysis revealed the expected 37 kD protein product in both MCL cell lines and in five frozen tumours, with the blastoid case having the highest expression level. Using a cut‐off of >10% immunolabelled cells for Mcl‐1, it was found that 12 of 36 MCL tumours were positive. Mcl‐1‐positive tumours had a higher frequency of blastoid/large‐cell morphology (8/12 versus 4/24, p = 0.009), p53 overexpression (3/10 versus 1/23, p = 0.04), and higher Ki67 immuno‐labelling (p = 0.002). It is concluded that expression of Mcl‐1 in MCL is heterogeneous. A relatively high level of Mcl‐1 expression correlates with high‐grade morphology, a high proliferative state, and p53 overexpression. Copyright © 2002 John Wiley & Sons, Ltd.
Type 2 nitric oxide synthase and protein nitration in chronic lung infection
Authors: Hopkins Natalie , Cadogan Elaine , Giles Shay , Bannigan John , McLoughlin Paul
Published: December 2002

Inflammation in the lung can lead to increased expression of inducible nitric oxide synthase (iNOS) and enhanced NO production. It has been postulated that the resultant highly reactive NO metabolites may have an important role in host defence, although they might also contribute to tissue damage. However, in a number of inflammatory lung diseases, including bronchiectasis, iNOS expression is increased but no elevation of airway NO can be detected. A potential explanation for this finding is that NO is rapidly scavenged by reaction with superoxide radicals, forming peroxynitrite, which is preferentially metabolized via nitration and nitrosation reactions. To test this hypothesis, anaesthetized, specific pathogen‐free rats were inoculated with Pseudomonas aeruginosa incorporated into agar beads (chronically infected group) or sterile agar beads (control group). Ten to 15 days later, the lungs were isolated and fixed. Pseudomonas organisms were isolated from the lungs of the chronically infected group. These lungs showed extensive inflammatory cell infiltration and tissue damage, which were not observed in control lungs. Expression of iNOS was increased in the chronically infected group when compared with the control group. However, the mean number of cells staining for nitrotyrosine in the chronically infected group was not significantly different from that in the controls, nor was there an excess of nitrotyrosine, nitrate, nitrite or nitrosothiol concentrations in the infected lungs. Thus, no evidence was found of increased NO metabolites in chronically infected lungs, including products of the peroxynitrite pathway. These findings suggest that chronic infection does not cause increased iNOS activity in the lung, despite increased expression of iNOS. Copyright © 2002 John Wiley & Sons, Ltd.
The yeast two‐hybrid system for identifying protein–protein interactions
Authors: Coates PJ , Hall PA
Published: December 2002

The yeast two‐hybrid assay is a system for identifying and analysing protein–protein interactions. Since the original description in 1989, the technique has provided insight into many biological pathways. A variety of adaptations to the technique have been developed that allow analysis of protein–DNA, protein–RNA, or small molecule–protein interactions. Recent developments now allow the use of these technologies to perform global analyses of all such interactions that occur in cells. The information gained from these approaches is uncovering many aspects of the complex networks that underlie normal cellular processes and how they are perturbed in disease states. Copyright © 2002 John Wiley & Sons, Ltd.
Kinetics of elimination of several heterocyclic carbamates in the gas phase
Authors: Brusco Yannely , Domínguez Rosa M. , Rotinov Alexandra , Herize Armando , Cordova Mary , Chuchani Gabriel
Published: December 2002

The kinetics of the gas‐phase elimination of several heterocyclic carbamates were determined in a static system over the temperature range 190.0–409.7 °C and the pressure range 26.5–125 Torr (1 Torr = 133.3 Pa). The reactions in seasoned vessels, with the free radical inhibitor cyclohexene and/or toluene always present, are homogeneous and unimolecular and obey a first‐order rate law. The observed rate coefficients are represented by the following Arrhenius equations: for tert‐butyl‐1‐pyrrolidine carboxylate, log k1 (s−1) = (11.36 ± 0.31) −(145.4 ± 3.1)­kJ mol−1 (2.303RT)−1; for 1‐(tert‐butoxycarbonyl)‐2‐pyrrolidinone, log k1 (s−1) = (11.54 ± 0.29) −(140.8 ± 2.8)­kJ mol−1 (2.303RT)−1; for tert‐butyl‐1‐pyrrole carboxylate, log k1 (s−1) = (12.12 ± 0.05) −(145.2 ± 1.0) kJ mol−1 (2.303RT)−1; and for 1‐ethylpiperazine carboxylate, log k1 (s−1) = (12.05 ± 0.19) −(188.2 ± 4.6) kJ mol−1 (2.303RT)−1. The saturated heterocyclic carbamates show a decrease in rates of elimination due to electronic factors. Heterocyclic carbamates with a nitrogen atom able to delocalize its electrons with π‐bonds present in the ring were found to enhance the rates due to resonance interactions. Copyright © 2002 John Wiley & Sons, Ltd.
Catalysis by organic phosphates of the glycation of human hemoglobin
Authors: Gil Herminia , Peña Mary , Vásquez Blanca , Uzcategui Jorge
Published: December 2002

The non‐enzymic glycation of hemoglobin is catalyzed by 3‐phosphoglycerate, 2‐phosphoglycerate and 2‐glycerolphosphate, but not by sodium propionate. Solvent isotope effects were determined (k/k). Catalysis by 3‐phosphoglycerate, 2‐phosphoglycerate and 2‐glycerolphosphate, the observer solvent isotope effect of unity, and flat proton inventory tend to suggest that the proton abstraction step of the Amadori rearrangement by 3‐phosphoglycerate, 2‐phosphoglycerate and 2‐glycerolphosphate is the rate‐determining step in the non‐enzymatic glycation of hemoglobin. The solvent isotope effect of unity, and a flat proton inventory for sodium propionate are indicative that a functional group on the hemoglobin is the proton‐abstracting base in the Amadori rearrangement. Copyright © 2002 John Wiley & Sons, Ltd.
Dipole polarizability of the pyrazabole molecule in solution
Authors: Alvarado Ysaías J. , Soscún Humberto , Velazco Wendy , Labarca Paola H. , Cubillan Nestor , Hernández Javier
Published: December 2002

The dynamic and static dipole polarizabilities of pyrazabole (PYRZ) were investigated using a refractometric method and theoretical calculations. The experimental properties were studied within the Singer–Garito and Proutiere and co‐workers' approaches for dilute cyclohexane, THF and CH3CN solutions. These methodologies were appropriate to quantify the electronic polarizability and electric deformability of pyrazabole in the optical regime. The static dipole polarizabilities of pyrazabole were obtained from extrapolation to zero frequency of the corresponding dispersion Cauchy‐type curves, which gave a monotonic increasing in function of the squared frequency. The differences between these curves were analyzed as a function of the solvent effects. Additionally, a comparative study with pyrazole was carried out. The results indicated that both the static and dynamic electronic polarizability of pyrazabole are determinated from the linear optical response of the pyrazole ring. In fact, the polarizability of the two pyrazole rings is approximately 80% of the overall value for pyrazabole. The theoretical static properties were evaluated by using ab initio (Hartree–Fock) and DFT (B3LYP) methods with the 6–31+G(d,p) and 6–311++G(3d,3p) basis sets. The calculations were performed with fully optimized geometries. The B3LYP average static electronic polarizability value of pyrazabole is 1.877 × 10−23 esu, and the differences from the experimental static values are within −1.2 to 8.5%. These variations are mainly due to the solvent effects. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and photophysical properties of Zn(II) porphyrin–C60 dyad with potential use in solar cells
Authors: Milanesio M. Elisa , Gervaldo Miguel , Otero Luis A. , Sereno Leonides , Silber Juana J. , Durantini Edgardo N.
Published: December 2002

Zn(II) porphyrin–C60 dyad (7) was synthesized by the coupling reaction between Zn(II) 5‐(4‐aminophenyl)‐10,15,20‐tris(4‐methoxylphenyl)porphyrin (4) and 1,2‐dihydro‐1,2‐methanofullerene[60]‐61‐carboxylic acid (6). The electron‐donor capacity of the porphyrin moiety in dyad 7 is enhanced by methoxy group substitution on the macrocycle peripheries and complexation with Zn(II). Spectroscopic studies showed only a very weak interaction between the chromophores in the grown state. The emission of the porphyrin moiety in dyad 7 is strongly quenched by the attached fullerene C60 moiety. Thermodynamically, dyad 7 shows a higher capacity to form a photoinduced charge‐separated state than the same dyad with free‐base porphyrin. This was confirmed by steady‐state photolysis in the presence of methylviologen as electron acceptor and N,N,N′,N′‐tetramethyl‐1,1′‐naphthidine as electron donor. Dyad 7 sensitizes a tin dioxide (SnO2) electrode and the generation of photoelectrical effect shows that a large photocurrent is generated for the dyad 7 in the region where C60 is mainly responsible for light absorption. Also, dyad 7 produces a higher photoelectric effect than the corresponding amidoporphyrin model. An alternative photoelectric mechanism, other than direct electron injection from the excited porphyrin to SnO2, could be occurring, probably involving a charge‐separated state of dyad 7. These results indicate that dyad 7 shows interesting properties for possible application in artificial solar energy conversion devices. Copyright © 2002 John Wiley & Sons, Ltd.
Thermodynamics of partitioning of some sulfonamides in 1‐octanol–buffer and liposome systems
Authors: Martínez Fleming , Gómez Alfredo
Published: December 2002

The thermodynamics of partitioning of some structurally related sulfonamides have been determined in 1‐octanol–aqueous buffer and liposome systems. The partition coefficients were approximately tenfold higher in liposomes compared with 1‐octanol. The enthalpies of transfer from aqueous media to organic systems were positive in liposomes but negative or positive in 1‐octanol, whereas the entropies of transfer were positive in almost all cases. Copyright © 2002 John Wiley & Sons, Ltd.
Theoretical study of electron transfer to neopentyl chloride and phenyl‐substituted derivatives: existence of radical anions as intermediates
Authors: Mariano D. , Vera A. , Pierini Adriana B.
Published: December 2002

Aliphatic halides such as neopentyl, bicycloalkyl and polycycloalkyl halides can be substituted by mechanisms that involve electron transfer (ET) steps. The homogeneous or heterogeneous ET to these compounds follows a concerted dissociative pathway, that is, the C–halogen bond cleaves as the electron is being transferred. The ET to alkyl halides substituted by π‐electron acceptors, on the other hand, may follow a stepwise mechanism with radical anions as intermediates. Both mechanistic pathways are analyzed on the basis of AM1, B3LYP and MP2 calculations for neopentyl chloride (6) and its phenyl‐ and benzyl‐substituted derivatives 1‐chloro‐2‐methyl‐2‐phenylpropane (neophyl chloride, 7) and 1‐chloro‐2,2‐dimethyl‐3‐phenylpropane (8). The solvent effect was evaluated with Tomasi's continuum polarized model. While relatively stable π radical anions appear as intermediates on the AM1 potential surfaces of 7 and 8, B3LYP and MP2 favor a concerted dissociative pathway for these compounds. Based on the B3LYP and MP2 results, it can be concluded that the driving force for the dissociative ET to the three compounds depends mainly on their C—C1 bond dissociation. The strength of the C—C1 bond is similar for 6 and 8 and lower for 7. The difference in the C—C1 bond strength of 7 and 8 is ascribed to differences in the stabilizing effect of the phenyl substituent, through a bridge of variable length, and also to the stability of the radical formed in the cleavage. The theoretical results obtained are of help in the interpretation of the relative experimental reactivity previously obtained for the family. Copyright © 2002 John Wiley & Sons, Ltd.
Nickel‐ and palladium‐catalyzed olefin polymerization under high pressures
Authors: Suzuki Noriyuki , Yu Jian , Masubuchi Yuji , Horiuchi Akira , Wakatsuki Yasuo
Published: December 2002

The polymerization of 1‐hexene under high pressures (100–750 MPa) was investigated with nickel–α‐diimine complex/methylaluminoxane and palladium–α‐diimine complex/methylaluminoxane as catalyst systems. The catalytic activity of both the nickel and palladium complexes monotonously increased as pressure rose and became two to four times higher than that observed at atmospheric pressure. Palladium catalysts gave poly(1‐hexene)s with higher molecular weights under high pressure, whereas nickel‐catalyzed high‐pressure polymerizations gave polymers with higher molecular weights only at rather low monomer concentrations. The living‐like character in the palladium‐catalyzed polymerizations was somewhat enhanced under higher pressures, whereas the nickel‐catalyzed polymerizations under high pressures were not living. More branches were found in the polymers produced by nickel catalysts at higher pressures. The chain‐transfer reaction seemed to be accelerated by the high pressure in the nickel‐catalyzed reactions, although this was not apparent in the palladium‐catalyzed reactions. Dimers formed and were accompanied by high molecular weight polymers when nickel catalysts were used under high pressures and at high monomer concentrations. The possibility that very congested five‐coordinated species act as key intermediates for the dimerization is discussed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 293–302, 2003
Determination of the cumulative degree of polymerization for the dead‐end polymerization of styrene
Authors: David G. , Boutevin B. , Robin J. J.
Published: December 2002

This article explores the use of a new relation correcting theoretical (DPn) with experimental values obtained in the dead‐end polymerization of styrene with azocompound. The syntheses were realized for several starting initiator‐to‐monomer ratios (C0's); values comprised between 10 and 0.1%, and the experimental (DPn) were obtained by size exclusion chromatography. Concerning the theoretical (DPn), a new relation is proposed considering the loss of initiating radicals [I · ] used in primary termination and both stationary states of I · and M · (macromolecular radicals) introduced as Bamford. Finally, (DPn)cum, previously defined by us, is introduced to consider the monomer conversion during oligomerization. Our relation fit very well in a large range of C0's, contrary to the application of the usual Mayo rule, and a discussion of validity is proposed. Our model also allows the prediction of (DPn)cum in a large range of telechelic oligomers from 10 to 150. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 236–247, 2003
Cationic cyclopolymerization of new divinyl ethers: The effect of ether and ester neighboring functional groups on their cyclopolymerization tendency
Authors: Rahman Md. Saifur , Hashimoto Tamotsu , Kodaira Toshiyuki
Published: December 2002

The cationic polymerization of two new divinyl ethers, 1‐(2‐vinyloxyethoxy)‐2‐[(2‐vinyloxyethoxy)carbonyl]benzene (2) and 1,2‐bis[(2‐vinyloxyethoxy)carbonyl]benzene (3), as well as 1,2‐bis(2‐vinyloxyethoxy)benzene (1), with BF3OEt2 in CH2Cl2 at 0 °C at low initial monomer concentrations ([M]0 = 0.15 and 0.075 M) gave soluble polymers with relatively high molecular weights and broad molecular weight distributions (MWDs), whereas reactions with the HCl/ZnCl2 initiating system yielded soluble polymers with relatively narrow MWDs (weight‐average molecular weight/number‐average molecular weight ≲ 1.6) under similar reaction conditions. An NMR structural analysis of the HCl/ZnCl2‐mediated polymers from the divinyl ethers showed that poly(1) had virtually no unreacted vinyl ether groups throughout the polymerization (monomer conversion = 28–98%), whereas poly(2) and poly(3) possessed some amount of unreacted vinyl ether groups in the initial stage of the polymerization; the content of the vinyl groups of poly(2) was 18 mol % at a 15% monomer conversion, and the content of the vinyl groups of poly(3) was 31 mol % at an 18% monomer conversion. Therefore, divinyl ether 1 underwent cyclopolymerization exclusively to give almost completely cyclized polymers [degree of cyclization (DC) ∼ 100%], whereas divinyl ethers 2 and 3 exhibited a lower cyclopolymerization tendency [DC for poly(2) = 82%; DC for poly(3) = 69%]. The differences in the cyclopolymerization tendencies among the divinyl ethers can be explained by the differences in the solvation powers of the neighboring functional groups adjacent to the vinyl ether moiety with the active center: the ether oxygen of the ether neighboring group solvates intramolecularly with the active center to accelerate the intramolecular propagation, but such an interaction is less effective with the more electron‐deficient oxygen attached to the carbonyl group of the ester neighboring group. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 281–292, 2003
Polymerization of vinyl chloride with half‐titanocene/methylaluminoxane catalysts
Authors: Endo Kiyoshi , Saitoh Makoto
Published: December 2002

The polymerization of vinyl chloride (VC) with half‐titanocene /methylaluminoxane (MAO) catalysts is investigated. The polymerization of VC with the Cp*Ti(OCH3)3/MAO catalyst (Cp* = η5‐pentamethylcyclopentadienyl) afforded high‐molecular‐weight poly(vinyl chloride) (PVC) in good yields, although the polymerization proceeded at a slow rate. With the Cp*TiCl3/MAO catalyst, the polymer was also obtained, but the polymer yield was lower than that with the Cp*Ti(OCH3)3/MAO catalyst. The polymerization of VC with the Cp*Ti(OCH3)3/MAO catalyst was influenced by the MAO/Ti mole ratio and reaction temperature, and the optimum was observed at the MAO/Ti mole ratio of about 10. The optimum reaction temperature of VC with the Cp*Ti(OCH3)3/MAO catalyst was around 20 °C. The stereoregularity of PVC obtained with the Cp*Ti(OCH3)3/MAO catalyst was different from that obtained with azobisisobutyronitrile, but highly stereoregular PVC could not be synthesized. From the elemental analyses, the 1H and 13C NMR spectra of the polymers, and the analysis of the reduction product from PVC to polyethylene, the polymer obtained with Cp*Ti(OCH3)3/MAO catalyst consisted of only regular head‐to‐tail units without any anomalous structure, whereas the Cp*TiCl3/MAO catalyst gave the PVC‐bearing anomalous units. The polymerization of VC with the Cp*Ti(OCH3)3/MAO catalyst did not inhibit even in the presence of radical inhibitors such as 2,2,6,6,‐tetrametylpiperidine‐1‐oxyl, indicating that the polymerization of VC did not proceed via a radical mechanism. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 248–256, 2003
Polyelectrolyte complexes. V. Solid‐state properties of some polycation/azo dye complexes controlled by the dye structure
Authors: Dragan Stela , Timpu Daniel
Published: December 2002

The solid‐state properties of some polycation/azo dye complexes according to the dye structure were studied in this work. One polycation contained about 95 mol % N,N‐dimethyl‐2‐hydroxypropyleneammonium chloride units in the backbone (PCA5), and eight azo dyes, different in either the number of sulfonic groups or their distribution, were used as opposite components. The selected azo dyes were as Crystal Scarlet, Congo Red, Crocein Scarlet MOO, Ponceau SS, Amaranth, Ponceau S, Direct Blue 1, and Direct Red 80. Information on the compensation degree of the oppositely charges was obtained by the elemental analysis of the solid‐state polycation/dye complexes (the experimental contents of chlorine, nitrogen, and sulfur were compared with the calculated values). Differential scanning calorimetry was employed to probe the strength of the intermolecular interactions in the PCA5/dye complexes. Wide‐angle X‐ray diffraction was used to assess the supramolecular order of the solid‐state complexes. The physical properties of the PCA5/azo dye complexes (the complex stoichiometry, glass‐transition temperature, decomposition temperature, and degree of supramolecular order) were influenced mainly by the dye structure but also by the polycation concentration and the presence of NaCl. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 264–272, 2003
Compositional and configurational sequence determination of methyl methacrylate/ethyl acrylate copolymers by one‐ and two‐dimensional nuclear magnetic resonance spectroscopy
Authors: Brar A. S. , Hooda Sunita , Kumar Rajeev
Published: December 2002

Ethyl acrylate (E)/methyl methacrylate (M) copolymers of different compositions were prepared, and their compositions were determined with 1H NMR spectra. The complete spectral assignments, in terms of the compositional and configurational sequences of these copolymers, were made with the help of distortionless enhancement by polarization transfer and two‐dimensional heteronuclear single quantum coherence spectroscopy. The α‐(CH3)M, CH (E), CH2, and 〉CO carbons of both M and E units were found to be sensitive to various compositional and configurational sequences. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 313–326, 2003
Beyond the rotamer library: Genetic algorithm combined with the disturbing mutation process for upbuilding protein side‐chains
Authors: Liu Zhijie , Jiang Lin , Gao Ying , Liang Shide , Chen Hao , Han Yuzhen , Lai Luhua
Published: December 2002

The disturbing genetic algorithm, incorporating the disturbing mutation process into the genetic algorithm flow, has been developed to extend the searching space of side‐chain conformations and to improve the quality of the rotamer library. Moreover, the growing generation amount idea, simulating the real situation of the natural evolution, is introduced to improve the searching speed. In the calculations using the pseudo energy scoring function of the root mean squared deviation, the disturbing genetic algorithm method has been shown to be highly efficient. With the real energy function based on AMBER force field, the program has been applied to rebuilding side‐chain conformations of 25 high‐quality crystallographic structures of single‐protein and protein–protein complexes. The averaged root mean standard deviation of atom coordinates in side‐chains and veracities of the torsion angles of χ1 and χ1 + χ2 are 1.165 Å, 88.2 and 72.9% for the buried residues, respectively, and 1.493 Å, 79.2 and 64.7% for all residues, showing that the method has equal precision to the program SCWRL, whereas it performs better in the prediction of buried residues and protein–protein interfaces. This method has been successfully used in redesigning the interface of the Basnase‐Barstar complex, indicating that it will have extensive application in protein design, protein sequence and structure relationship studies, and research on protein–protein interaction. Proteins 2003;50:49–62. © 2002 Wiley‐Liss, Inc.
Rigid body response of base‐isolated structures
Authors: Kulkarni Jeevan A. , Jangid R. S.
Published: December 2002

The superstructure of a base‐isolated building is relatively rigid compared with the isolation system. This can lead to idealization of the superstructure as a rigid body, modelling the base‐isolated structure as a single‐degree‐of‐freedom system. Such analysis significantly reduces the computational efforts required to design the base‐isolated structure under seismic loading. In this study, a comparison is made of the seismic response of a multi‐storey base‐isolated building by idealizing the superstructure as rigid and flexible. Various isolation systems considered include elastomeric bearings (with and without lead cores) as well as sliding systems. The governing equations of motion of the isolated structural system are derived and the response of the system is obtained for a specified time‐history of earthquake ground motion. The top floor acceleration and bearing displacement of the system are plotted for different system parameters and compared with the corresponding response under rigid superstructure conditions to study the influence of superstructure flexibility. The comparison of the response is made under various isolation system parameters (i.e. isolation period, damping, yield strength of the elastomeric bearings and friction coefficient of sliding systems). It is observed that the bearing displacement can be accurately obtained by modelling the superstructure as a rigid body in a base‐isolated structure. Further, such approximation is also justified for floor accelerations of a relatively stiff superstructure isolated by elastomeric bearings. However, the rigid superstructure approach significantly under estimates the floor accelerations for the structure isolated by sliding systems. Copyright © 2002 John Wiley & Sons, Ltd.
A cloud‐resolving regional simulation of tropical cyclone formation
Authors: Powers Jordan G. , Davis Christopher A.
Published: December 2002

The development of Tropical Cyclone Diana (1984) is simulated with a mesoscale model using 1.2 km grid spacing over a regional‐scale (>1000 km) domain in the first known experiment of this kind. With only a synoptic‐scale disturbance in the initial conditions, the model first develops a mesoscale convective system along a remnant frontal zone, which yields a mesoscale vortex. After a period of quiescence, banded convection organizes about the vortex from isolated, grid‐resolved cells, with the system becoming warm‐core and intensifying into Tropical Storm Diana. Copyright © 2002 Royal Meteorological Society.
CALCIUM PUMP PHOSPHOENZYME FROM YOUNG AND OLD HUMAN RED CELLS
Authors: Romero Pedro J. , Salas Valentina , Hernández Concepción
Published: December 2002

An increase in intracellular Ca2+ occurs during ageing of human erythrocytes in vivo. The aged cells show a reduced capacity for active Ca2+ extrusion. Such a defect may arise from pump proteolysis, due to calpain activation by the raised intracellular Ca2+. To test this possibility, Ca2+ pump phosphorylation by [γ‐32P]ATP was studied on percoll‐separated young and old human erythrocytes. After phosphorylation for 30s with Ca2+, the amount of phosphoenzyme produced by the young cell membranes was 50% that of the old cells. With Ca2+ plus La3+, in contrast, the phosphoenzyme level was nearly the same in both preparations. After a prolonged phosphorylation period (50–90s), the phosphoenzyme reached almost identical equilibrium levels in both membrane preparations. On the other hand, a single Ca2+‐dependent radioactive band of about 150kDa was apparent in both preparations after acidic electrophoresis. Likewise, Western blotting using 5F10 monoclonal antibody also detected a single band of similar molecular weight. These results demonstrate that there is no alteration in either molecular mass or number of active Ca2+ pump units during cell ageing, thus indicating that the reduced Ca2+ pumping activity of aged cells does not arise from pump proteolysis.
CELL ADHESION DURING THE MIGRATORY SLUG STAGE OF DICTYOSTELIUM DISCOIDEUM
Authors: Bowers‐Morrow Vivienne M. , Ali Sinan O. , Williams Keith L.
Published: December 2002

Prespore‐specific Antigen (PsA) is selectively expressed on the surface of prespore cells at the multicellular migratory slug stage of Dictyostelium discoideum development. It is a developmentally regulated glycoprotein that is anchored to the cell membrane through a glycosyl phosphatidylinositol (GPI) anchor. We present the results of an in vitro immunological investigation of the hypothesis that PsA functions as a cell adhesion molecule (CAM), and of a ligand‐binding assay indicating that PsA has cell membrane binding partner(s). This is the first evidence to implicate a direct role for a putative CAM in cell—cell adhesion during the multicellular migratory slug stage of D. discoideum development. Cell—cell adhesion assays were carried out in the presence or absence of the monoclonal antibody (mAb) MUD1 that has a single antigenic determinant: a peptide epitope on PsA. These assays showed specific inhibition of cell—cell adhesion by MUD1. Further, it was found that a purified recombinant form of PsA (rPsA), can neutralize the inhibitory effect of MUD1; the inhibitory effect on cell—cell adhesion is primarily due to the blocking of PsA by the mAb. The resistance of aggregates to dissociation in the presence of 10mM EDTA (ethylenediamintetraacetic acid) indicates that PsA mediates EDTA‐stable cell—cell contacts, and that PsA‐mediated cell adhesion is likely to be independent of divalent cations such as Ca2+ or Mg2+.
A SIMPLE NON‐ENZYMATIC METHOD FOR THE ISOLATION OF HIGH YIELDS OF FUNCTIONAL RAT HEPATOCYTES
Authors: Kravchenko L. , Petrenko A. , Shanina I. , Fuller B.
Published: December 2002

A method for isolation of rat hepatocytes using liver perfusion by ethylenediamine tetra‐acetic acid (EDTA)‐containing sucrose solution and mechanical tissue disaggregation by controlled vibration (MVD) is described. The yields of hepatocytes produced by this method were similar to those obtained using collagenase perfusion. The cells had well preserved membrane integrity as judged by the trypan blue staining test (91±4%), ATP contents, rates of endogenous respiration and enzyme leakage that indicated they were functional cells. There was little evidence of expression of latent damage when the cells were stored either at 37°C (by pre‐incubation) or at 4°C. This method can be used to isolate high yields of functional cells from rat liver if the collagenase perfusion technique is not available.
REGULATION OF LEUKOTRIENE SYNTHESIS BY ARACHIDONIC ACID IN HUMAN POLYMORPHONUCLEAR LEUKOCYTE ADHESIVE INTERACTIONS IS DEPENDENT ON THE PRESENCE OF ALBUMIN
Authors: Pushkareva Marina A. , Turutin Denis V. , Sud'ina Galina F.
Published: December 2002

We have previously demonstrated that the pretreatment of polymorphonuclear leukocytes (PMNs) with the chemotherapeutic drug, Suramin, increases both cell attachment and inhibits calcium ionophore A23187‐stimulated leukotriene (LT) synthesis. Here, we examined the effects of extracellular arachidonic acid (AA) and albumin on attachment and LT synthesis in the interaction of PMNs with both collagen‐coated surfaces and human umbilical vein endothelial cell (HUVEC) monolayers. Suramin decreased the release of radiolabelled AA and 5‐lipoxygenase metabolites by [14C‐AA]‐prelabelled PMNs stimulated with A23187, with and without human serum albumin (HSA) in the culture medium. Addition of 1μM AA together with calcium ionophore stimulated the release of endogenous AA to the same level as control and Suramin‐pretreated cells, but attachment was unaffected and LT synthesis was still inhibited with Suramin treatment. Using 24μM AA, regulation of LT synthesis was dependent on the presence of HSA in the medium. Without HSA, 24μM AA induced detachment of PMNs and increased LT synthesis in Suramin‐treated cells above the control level. In the presence of HSA, 24μM AA did not influence PMN attachment or abolish Suramin‐induced inhibition of LT synthesis. These results suggest that tight attachment of PMNs to a solid surface leads to decreased LT synthesis during subsequent stimulation of the cells by A23187 in the presence or absence of exogenous substrate.
MECHANISTICS OF AMOEBOID LOCOMOTION: SIGNAL TO FORCES
Authors: Fukui Yoshio
Published: December 2002

Dictyostelium serves as an ideal model system for studying the molecular and structural properties of the actomyosin and microtubule systems. This organism also has been the vehicle on which the gene‐targeting technique was pioneered. Dictyostelium also represents a small number of organisms whose chemotactic ligand‐receptor mechanism has been well characterized. This article reviews recent advances in studies of the actin‐based cytoskeletal system in Dictyostelium, focusing on the mechanistic aspects of the amoeboid motion. Special emphasis is placed on the recently identified cell‐substrate‐anchoring structures ‘eupodia’, and the measurement of single‐cell migration forces. The recent advances in signal transduction cascade is also discussed with relevance to the mechanistics in amoeboid locomotion.
TELOMERASE‐DEPENDENT REACTIVATION OF DNA SYNTHESIS IN MACROPHAGES IMPLIES ALTERATION OF TELOMERES
Authors: Yegorov Y. E. , Kazimirchuk E. V. , Terekhov S. M. , Karachentsev D. N. , Shirokova E. A. , Khandazhinskaya A. L. , Meshcheryakova J. A. , Corey D. R. , Zelenin A. V.
Published: December 2002

In previous work we demonstrated that various types of cultured cells with a limited life span could not reactivate DNA synthesis in the nuclei of mouse peritoneal macrophages in heterokaryons. We now investigate the role of telomerase in the process of the macrophage nucleus reactivation in heterokaryons with immortal telomerase‐positive 3T3 Swiss mouse fibroblasts and human fibroblasts with introduced hTERT gene. We report that introduction of the hTERT gene into human diploid fibroblasts results in emergence of telomerase activity in these cells and the ability to induce the reactivation of DNA synthesis in the macrophage nuclei in heterokaryons. Inhibition of telomerase activity in heterokaryons by reverse transcriptase inhibitors (azidothymidine and guanosine polyphosphonate analogues) and by a 2′‐O‐methyl‐RNA oligonucleotide anti‐sense to the template region of telomerase RNA, block reactivation of DNA synthesis in macrophage nuclei without inhibiting DNA synthesis in the nuclei of fibroblasts. Our results suggest alterations (shortening or damage) in the macrophage telomere structure. As far as we know, heterokaryons with macrophages are the first cellular model for rapid investigation of the effects of telomerase inhibitors.
PARACRINE ACTION OF TRANSFORMING GROWTH FACTOR‐ALPHA IN RECTAL CRYPT EPITHELIUM OF HUMANS
Authors: Cameron Ivan L. , Hardman W. Elaine
Published: December 2002

Colon and rectal mucosal crypt epithelium is a rapidly renewing cell population, where cell proliferation is normally balanced by cell loss. This report concerns the putative paracrine action of transforming growth factor α(TGF‐α) in this homeostatic process. Immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and TGF‐α was performed on biopsy specimens of rectal mucosa taken from consenting patients. The height of the proliferative compartment in mid‐axially sectioned crypts in each individual was determined from the distribution of PCNA stained cells. The number of TGF‐α stained cells that exhibited intense positive staining in a continuous column from the mouth down the side of the crypt was also scored in each individual patient. There was a significant positive correlation (P=0.05,n =22 patients) between the height of the proliferative compartment and the number of cells staining for TGF‐α. Non‐cellular TGF‐α reactivity was also observed in the lamina propria adjacent to the TGF‐α reactive epithelial cells, indicating secretion of TGF‐α by these epithelial cells. These findings suggest that TGF‐α is released from epithelial cells in the upper compartment of the crypt into the adjacent lamina propria and then diffuses to the epithelial cells in the lower part of the crypt, resulting in expansion of the proliferative compartment.
MODIFICATION OF OSCILLATORY BEHAVIOUR OF PROTEIN TYROSINE KINASE AND PHOSPHATASE DURING ALL‐TRANS RETINOIC ACID‐INDUCED DIFFFERENTIATION OF LEUKAEMIC CELLS
Authors: Calvert‐Evers J. L. , Hammond K. D.
Published: December 2002

Granulocytic maturation of human acute promyelocytic leukaemic (HL‐60) cells was induced using all‐trans retinoic acid (ATRA). Time‐dependent changes in the enzyme activities of protein tyrosine phosphatase (PTP) and protein tyrosine kinase (PTK), and the total extractable protein content were monitored in proliferating and differentiating cells. The existence of periodicity was demonstrated clearly in both PTP and PTK enzyme activities and in the amount of protein extracted from the cells. Following ATRA treatment, differentiation‐induced changes in rhythmic characteristics such as period and amplitude were evident. A noticeable effect was that of ATRA on the enzyme activity of PTP, for which four distinct patterns of oscillatory behaviour were identified. This study examines these changes, in an attempt to gain insight into the role which biochemical oscillators may play in the regulation of molecular control mechanisms.
THE SIGNIFICANCE OF α5β1 INTEGRIN DEPENDENT AND INDEPENDENT ACTIN CYTOSKELTON ORGANIZATION IN CELL TRANSFORMATION AND SURVIVAL
Authors: Rajeswari J. , Pande Gopal
Published: December 2002

Cell—matrix and cell—cell interactions are important physiological determinants of cell growth, survival and transformation. Cell adhesion to the extra cellular matrix (ECM) via integrins also crucially influences the organization of the cytoskeleton. It triggers a cascade of intracellular biochemical events, which regulate cell viability and growth. We have studied the relationship between cell attachment to the substratum and cytoskeletal organization and cell survival and transformation. Our results demonstrate that in the absence of attachment to the substratum, adhesion‐dependent fibroblasts exhibit rapid loss of viability. However, a small percentage of cells survive even after remaining non‐adherent for 16h. The adherent and non‐adherent cells differ from one another both morphologically and physiologically. The latter show a loss of α5β1 integrin expression on their surface and bind non‐specifically to the substratum and ECM, thereby activating certain pathways more efficiently than adherent cells. We have also shown that non‐adherent cells grow faster and have worse cytoskeletal organization after attachment to the substratum, and do not form focal adhesions or actin stress fibres. Hence, our data suggests that rat fibroblasts in prolonged suspension exhibit some properties that are comparable to cells undergoing transformation, by adapting integrin‐dependent or independent signalling pathways for their survival.
EXOGENOUS ACTIVIN INCREASES THE PROPORTION OF INSULIN CELLS IN THE DEVELOPING CHICK PANCREAS IN CULTURE
Authors: Penny Clem , Kramer Beverley
Published: December 2002

As activin is believed to be a key signalling factor during early pancreatic development, its influence on the proliferation and/or determination of insulin cells in the developing chick dorsal pancreatic bud was investigated. Dorsal pancreatic buds of 5‐day‐old chick embryos were explanted on to Matrigel and cultured in serum‐free medium (Ham's F12.ITS), to which 1 or 10ng/ml activin was added. After 7 days in culture, the explants were processed for immunocytochemistry and the insulin‐positive cells were scored and expressed as a proportion of the sum of insulin and glucagon cells. When compared to the control cultures (Hams F12.ITS alone), activin treatment resulted in respective increases in the proportion of insulin cells of 1.6 and 1.9 fold. It is suggested that activin treatment favours differentiation of the insulin cell pathway relative to glucagon cells.
A revision of the species of the Rhizocarpon hochstetteri group occurring in the British Isles
Authors: Fryday Alan M.
Published: December 2002

Rhizocarpon hochstetteri s. str. is shown to be an upland/montane species with relatively large ascospores. The name Rhizocarpon infernulum is resurrected for the species with smaller ascospores previously included within R. hochstetteri, but which is probably more closely related to R. cinereovirens. Lectotypes are chosen for a number of taxa, including R. cinereovirens and R. infernulum, and descriptions provided for two new taxa with small hyaline, 1–septate ascospores: R. caesium, which occurs on damp, mildly basic rocks in oceanic areas, and R. infernulum f. sylvaticum occurring on siliceous rocks in damp deciduous woodlands. All these taxa are known also from North America. Rhizocarpon discoense is shown to be a distinct species, not a synonym of R. cinereovirens. The different ascospore dimensions reported for R. hochstetteri by British and European authors are shown to be due to confusion between R. hochstetteri and R. polycarpum. A number of morphological characters are evaluated regarding their relevance to species separation in Rhizocarpon and the name Macrocarpa-green is proposed for the olivaceous pigment present in most species of Rhizocarpon and Porpidia. A key is provided for the species of Rhizocarpon with hyaline, 1– septate ascospores.
The lichenicolous species of Odontotrema (Syn. Lethariicola) (Ascomycota, Ostropales)
Authors: Diederich Paul , Zhurbenko Mikhail , Etayo Javier
Published: December 2002

The genus Lethariicola is shown to be a synonym of Odontotrema. Fifteen lichenicolous species are recognized: O. bryoriae sp. nov. (on Bryoria), O. cuculare comb. nov. (on Parmeliopsis hyperopta), O. figulinum comb. nov. (on Lecanora polytropa) O. intermedium sp. nov. (on Thamnolia), O. lecanorae sp. nov. (on Lecanora), O. melaneliae sp. nov. (on Melanelia), O. ochrolechiae sp. nov. (on Ochrolechia), O. pertusariae sp. nov. (on Pertusaria hymenea), O. rhizocarpicola sp. nov. (on Rhizocarpon) O. santessonii sp. nov. (on Thamnolia), O. sipei comb. nov. (on Letharia), O. thamnoliae sp. nov. (on Thamnolia), and three undescribed species on Lecanora, Mycoblastus and Usnea. The type of O. cuculare has two distinct lichenicolous species of Odontotrema, and the name is lectotypified on the species growing on Parmeliopsis. A key is given to all lichenicolous species of Odontotrema and Paralethariicola.
Halogenated anthraquinones from the rare southern Illinois lichen Lasallia Papulosa
Authors: Cohen Peter A.
Published: December 2002

Four anthraquinones were isolated from the foliose lichen, Lasallia papulosa (Ach.) Llano. Two of the anthraquinones are known compounds, previously isolated from Lasallia papulosa, while the other two were reported previously as secondary metabolites from laboratory-cultured Nephroma laevigatum, and are isolated here for the first time from lichens in their natural habitat. All compounds were characterized by UV spectrophotometry, mass spectrometry, 1H NMR and 13C NMR. The products were identified as 7-chloroemodin, valsarin (7-chloro-5-hydroxyemodin), 5-chloro-1-O-methylemodin and 5-chloro-1-O-methyl-ω-hydroxyemodin.
A new fertile species of Menegazzia and notes on two sorediate species from the Neotropics
Authors: Bjerke Jarle W.
Published: December 2002

Menegazzia neotropica sp. nov. is described from upper montane forest remnants and paramos in Ecuador, Colombia and Venezuela. It is characterized by short-pedicellate apothecia with ridged margins that partly obscure the discs, and by narrow, glossy lobes with brown-black margins. Menegazzia dissecta is recorded from South America for the first time and M. terebrata is recorded from Colombia and Ecuador for the first time.
Immunological aspects of endometriosis
Authors: Dmowski W.P.
Published: December 2002

During the past decade, evidence has accumulated indicating an association between endometriosis and changes in humoral and cell‐mediated immunity. However, it is not clear whether immune changes are the sequelae or play a role in the etiopathogenesis of the disease. The latter concept is supported by the observation that exposure of rhesus monkeys to radiation or immunotoxicants leads several years later to an increase in frequency and severity of endometriosis. Studies from our laboratories support the theory that endometrial cells misplaced during menses can implant in ectopic locations only in women with genetically or environmentally altered cell‐mediated immune function. Development of endometriosis may then prompt a humoral response in some women, which results in the production of autoantibodies to endometrial cells or cell‐derived antigens. These autoantibodies may cross‐react with the uterine endometrium, interfere with implantation, and cause infertility or early spontaneous abortions. We recently observed that the presence of autoantibodies in endometriosis was associated with significantly lower in vitro fertilization/embryo transfer pregnancy rates. Interestingly, in about 30% of women with unexplained infertility, immune changes characteristic of endometriosis were also present, suggesting a subclinical form of this disease. We conclude that: (1) women with unexplained infertility should have studies of the immune function to rule out subclinical form of endometriosis: (2) evaluation of infertility in women with endometriosis should include an assessment of autoantibody status: and (3) treatment methods involving autoantibody suppression should be considered in women with endometriosis positive for autoantibodies.
The impact of bone loss in women with endometriosis
Authors: Stevenson J.C
Published: December 2002

Low peak adult bone mass in a premenopausal woman puts her at increased risk for osteoporosis postmenopausally. Episodes of hypo‐estrogenism premenopausally are associated with loss of bone density. This is seen with gonadotropin‐releasing hormone agonist therapy for endometriosis, and thus prolonged or repeated courses of such treatment may increase the future risk of osteoporosis. Danazol and related compounds do not result in any bone loss but may have certain metabolic disadvantages.
Changes in bone mineral content following hormone treatment for endometriosis
Authors: Fukushima M.
Published: December 2002

The effects of danazol and buserelin on the bone mineral content (BMC) of 19 Japanese women with endometriosis were studied. Subjects received 24‐week courses of oral danazol (400 mg/day) or intranasal buserelin (900 μg/day). Trabecular BMC of the 3rd lumbar vertebra (L3) was monitored by computerized tomography scans pretreatment, at the end of treatment and 6 months post‐treatment. In the buserelin group there was a significant decrease in BMC (10–25.4%, P < 0.01) which was not fully reversed 6 months after therapy, and increased parameters of bone resorption. In the danazol group, there was a slight gain in BMC despite a decrease in serum estrogen. Danazol and buserelin have similar success in the treatment of endometriosis, but the decrease in BMC at L3 suggests that cumulative bone loss may follow repeated buserelin therapy.