bluuebunny/crossref_metadata_2025 huggingface dataset:
mRNAs Encoding Telomerase Components and Regulators Are Controlled by
UPF
Genes in
Saccharomyces cerevisiae
Authors: Dahlseid Jeffrey N. , Lew-Smith Jodi , Lelivelt Michael J. , Enomoto Shinichiro , Ford Amanda , Desruisseaux Michelle , McClellan Mark , Lue Neal , Culbertson Michael R. , Berman Judith
Published: February 2003

Telomeres, the chromosome ends, are maintained by a balance of activities that erode and replace the terminal DNA sequences. Furthermore, telomere-proximal genes are often silenced in an epigenetic manner. In
Saccharomyces cerevisiae
, average telomere length and telomeric silencing are reduced by loss of function of
UPF
genes required in the nonsense-mediated mRNA decay (NMD) pathway. Because NMD controls the mRNA levels of several hundred wild-type genes, we tested the hypothesis that NMD affects the expression of genes important for telomere functions. In
upf
mutants, high-density oligonucleotide microarrays and Northern blots revealed that the levels of mRNAs were increased for genes encoding the telomerase catalytic subunit (Est2p), in vivo regulators of telomerase (Est1p, Est3p, Stn1p, and Ten1p), and proteins that affect telomeric chromatin structure (Sas2p and Orc5p). We investigated whether overexpressing these genes could mimic the telomere length and telomeric silencing phenotypes seen previously in
upf
mutant strains. Increased dosage of
STN1
, especially in combination with increased dosage of
TEN1
, resulted in reduced telomere length that was indistinguishable from that in
upf
mutants. Increased levels of
STN1
together with
EST2
resulted in reduced telomeric silencing like that of
upf
mutants. The half-life of
STN1
mRNA was not altered in
upf
mutant strains, suggesting that an NMD-controlled transcription factor regulates the levels of
STN1
mRNA. Together, these results suggest that NMD maintains the balance of gene products that control telomere length and telomeric silencing primarily by maintaining appropriate levels of
STN1
,
TEN1
, and
EST2
mRNA.
TOK Homologue in
Neurospora crassa
: First Cloning and Functional Characterization of an Ion Channel in a Filamentous Fungus
Authors: Roberts Stephen K.
Published: February 2003

In contrast to animal and plant cells, very little is known of ion channel function in fungal physiology. The life cycle of most fungi depends on the “filamentous” polarized growth of hyphal cells; however, no ion channels have been cloned from filamentous fungi and comparatively few preliminary recordings of ion channel activity have been made. In an attempt to gain an insight into the role of ion channels in fungal hyphal physiology, a homolog of the yeast K
+
channel (ScTOK1) was cloned from the filamentous fungus,
Neurospora crassa
. The patch clamp technique was used to investigate the biophysical properties of the
N. crassa
K
+
channel (NcTOKA) after heterologous expression of NcTOKA in yeast. NcTOKA mediated mainly time-dependent outward whole-cell currents, and the reversal potential of these currents indicated that it conducted K
+
efflux. NcTOKA channel gating was sensitive to extracellular K
+
such that channel activation was dependent on the reversal potential for K
+
. However, expression of NcTOKA was able to overcome the K
+
auxotrophy of a yeast mutant missing the K
+
uptake transporters TRK1 and TRK2, suggesting that NcTOKA also mediated K
+
influx. Consistent with this, close inspection of NcTOKA-mediated currents revealed small inward K
+
currents at potentials negative of E
K
. NcTOKA single-channel activity was characterized by rapid flickering between the open and closed states with a unitary conductance of 16 pS. NcTOKA was effectively blocked by extracellular Ca
2+
, verapamil, quinine, and TEA
+
but was insensitive to Cs
+
, 4-aminopyridine, and glibenclamide. The physiological significance of NcTOKA is discussed in the context of its biophysical properties.
Yap1 Accumulates in the Nucleus in Response to Carbon Stress in
Saccharomyces cerevisiae
Authors: Wiatrowski Heather A. , Carlson Marian
Published: February 2003

Yap1 is a transcription factor of the AP-1 family that is required for the adaptive response to oxidative stress in
Saccharomyces cerevisiae
. We recovered Yap1 in a two-hybrid screen for proteins that interact with the Sip2 subunit of the Snf1 protein kinase, which is required for the adaptation of cells to glucose limitation. Yap1 becomes enriched in the nucleus when cells are subjected to oxidative stress. We show that the localization of Yap1 is similarly sensitive to carbon stress. When glucose-grown cells were shifted to medium containing glycerol or no added carbon source, green fluorescent protein (GFP)-Yap1 accumulated in the nucleus. After adaptation to growth in glycerol, GFP-Yap1 was again primarily cytoplasmic. Nuclear accumulation was independent of respiration and of the Snf1, PKA, TOR, and Yak1 pathways, and the mechanism is distinct from that involved in the response to hydrogen peroxide. Addition of glutathione to the medium inhibited nuclear accumulation of GFP-Yap1 in response to carbon stress but did not affect the relocalization of Gal83 or Mig1. Other stresses such as increased temperature, acidic pH, and ionic stress did not cause nuclear enrichment of GFP-Yap1. These findings suggest a role for Yap1 in the response to carbon stress.
Expressed Sequence Tag Analysis of the Human Pathogen
Paracoccidioides brasiliensis
Yeast Phase: Identification of Putative Homologues of
Candida albicans
Virulence and Pathogenicity Genes
Authors: Goldman Gustavo H. , dos Reis Marques Everaldo , Duarte Ribeiro Diógenes Custódio , de Souza Bernardes Luciano Ângelo , Quiapin Andréa Carla , Vitorelli Patrícia Marostica , Savoldi Marcela , Semighini Camile P. , de Oliveira Regina C. , Nunes Luiz R. , Travassos Luiz R. , Puccia Rosana , Batista Wagner L. , Ferreira Leslie Ecker , Moreira Júlio C. , Bogossian Ana Paula , Tekaia Fredj , Nobrega Marina Pasetto , Nobrega Francisco G. , Goldman Maria Helena S.
Published: February 2003

Paracoccidioides brasiliensis
, a thermodimorphic fungus, is the causative agent of the prevalent systemic mycosis in Latin America, paracoccidioidomycosis. We present here a survey of expressed genes in the yeast pathogenic phase of
P. brasiliensis
. We obtained 13,490 expressed sequence tags from both 5′ and 3′ ends. Clustering analysis yielded the partial sequences of 4,692 expressed genes that were functionally classified by similarity to known genes. We have identified several
Candida albicans
virulence and pathogenicity homologues in
P. brasiliensis
. Furthermore, we have analyzed the expression of some of these genes during the dimorphic yeast-mycelium-yeast transition by real-time quantitative reverse transcription-PCR. Clustering analysis of the mycelium-yeast transition revealed three groups: (i) RBT, hydrophobin, and isocitrate lyase; (ii) malate dehydrogenase, contigs Pb1067 and Pb1145, GPI, and alternative oxidase; and (iii) ubiquitin, delta-9-desaturase, HSP70, HSP82, and HSP104. The first two groups displayed high mRNA expression in the mycelial phase, whereas the third group showed higher mRNA expression in the yeast phase. Our results suggest the possible conservation of pathogenicity and virulence mechanisms among fungi, expand considerably gene identification in
P. brasiliensis
, and provide a broader basis for further progress in understanding its biological peculiarities.
Jumping and kicking in bush crickets
Authors: Burrows Malcolm , Morris Oliver
Published: February 2003

Bush crickets have long, thin hind legs but jump and kick rapidly. The mechanisms underlying these fast movements were analysed by correlating the activity of femoral muscles in a hind leg with the movements of the legs and body captured in high-speed images.

A female Pholidoptera griseoaptera weighing 600 mg can jump a horizontal distance of 300 mm from a takeoff angle of 34° and at a velocity of 2.1 m s-1, gaining 1350μJ of kinetic energy. The body is accelerated at up to 114 m s-2, and the tibiae of the hind legs extend fully within 30 ms at maximal rotational velocities of 13 500 deg. s-1. Such performance requires a minimal power output of 40 mW. Ruddering movements of the hind legs may contribute to the stability of the body once the insect is airborne. During kicking, a hind tibia is extended completely within 10 ms with rotational velocities three times higher at 41 800 deg. s-1.

Before a kick, high-speed images show no distortions of the hind femoro-tibial joints or of the small semi-lunar groove in the distal femur. Both kicks and jumps can be generated without full flexion of the hind tibiae. Some kicks involve a brief, 40-90 ms, period of co-contraction between the extensor and flexor tibiae muscles, but others can be generated by contraction of the extensor without a preceding co-contraction with the flexor. In the latter kicks, the initial flexion of the tibia is generated by a burst of flexor spikes, which then stop before spikes occur in the fast extensor tibiae(FETi) motor neuron. The rapid extension of the tibia can follow directly upon these spikes or can be delayed by as long as 40 ms. The velocity of tibial movement is positively correlated with the number of FETi spikes.

The hind legs are 1.5 times longer than the body and more than four times longer than the front legs. The mechanical advantage of the hind leg flexor muscle over the extensor is greater at flexed joint angles and is enhanced by a pad of tissue on its tendon that slides over a protuberance in the ventral wall of the distal femur. The balance of forces in the extensor and flexor muscles, coupled with their changing lever ratio at different joint positions,appears to determine the point of tibial release and to enable rapid movements without an obligatory co-contraction of the two muscles.
Acutely altered hemodynamics following venous obstruction in the early chick embryo
Authors: Stekelenburg-de Vos Sandra , Ursem Nicolette T. C. , Hop Wim C. J. , Wladimiroff Juriy W. , Gittenberger-de Groot Adriana C. , Poelmann Robert E.
Published: February 2003

In the venous clip model specific cardiac malformations are induced in the chick embryo by obstructing the right lateral vitelline vein with a microclip. Clipping alters venous return and intracardiac laminar blood flow patterns,with secondary effects on the mechanical load of the embryonic myocardium. We investigated the instantaneous effects of clipping the right lateral vitelline vein on hemodynamics in the stage-17 chick embryo. 32 chick embryos HH 17 were subdivided into venous clipped (N=16) and matched control embryos(N=16). Dorsal aortic blood flow velocity was measured with a 20 MHz pulsed Doppler meter. A time series of eight successive measurements per embryo was made starting just before clipping and ending 5h after clipping. Heart rate, peak systolic velocity, time-averaged velocity, peak blood flow,mean blood flow, peak acceleration and stroke volume were determined. All hemodynamic parameters decreased acutely after venous clipping and only three out of seven parameters (heart rate, time-averaged velocity and mean blood flow) showed a recovery to baseline values during the 5h study period. We conclude that the experimental alteration of venous return has major acute effects on hemodynamics in the chick embryo. These effects may be responsible for the observed cardiac malformations after clipping.
Rapid prototyping models and their quality evaluation using reverse engineering
Authors: Zhang S J , Raja V H , Fernandes K J , Ryall C , Wimpenny D
Published: February 2003

This paper presents the results of a systematic research project carried out for evaluating the quality of a wide range of rapid prototyping (RP) models used in the manufacture of wax patterns for investment casting. The evaluation was based on geometrical accuracy, surface finish, visual inspection of RP patterns and the final casting process, compatibility with the standard casting process and casting quality based on X-ray analysis. A real high-integrity aerospace component was selected for these trials. Eight RP models of this component were constructed for each of the six different RP technologies. Based upon the requirements of the industrial applications, eight geometrical parameters for the example component have been chosen for the evaluation. These are four orientation angles, two diameters, one roundness and one surface flatness. Reverse engineering technology has been applied for the measurement of these eight parameters to overcome the difficulties faced by conventional inspection methods. In this paper it is hoped to present a comprehensive evaluation of the quality of the RP models for each RP method investigated. The findings provide meaningful information for industry to select RP technology best suited to their production requirements in order to reduce the leading time of product development.
Influence of forming conditions on the titanium model in rapid prototyping with the selective laser melting process
Authors: Abe F , Costa Santos E , Kitamura Y , Osakada K , Shiomi M
Published: February 2003

In order to evaluate the titanium model to be used for medical purposes in rapid prototyping with the selective laser melting process, the influence of forming conditions on the mechanical properties is investigated. The density and mechanical properties such as tensile and fatigue strengths of the model are measured. In the selective laser melting process, a pulsed yttrium aluminium garnet (YAG) laser with average power of 50 W and maximum peak power of 3 kW is used. The specimens for measuring density and mechanical properties are made from commercial pure titanium powders (grade 1) in a controlled atmosphere with argon gas. It is found that the relative density of the model is higher than 92 per cent and some powder particles remain within the solidified model. The scan speed affects the tensile strength strongly and the tensile strength is around 120 per cent of the standard value of the solid pure titanium when the scan speed is appropriate. However, the fatigue strength is low, about 10 per cent of the solid one, which is still to be improved by post-processing.
Erotomanic stalking in evolutionary perspective
Authors: Brüne Martin
Published: February 2003

Erotomania, the delusion of being loved by another person, comprises marked sex differences concerning prevalence rates and behavior. Whereas traditional psychiatry has considered erotomania to be almost entirely restricted to women, recent studies have revealed that criminal offenses associated with the condition occur much more frequently in men. The main hypothesis of this article is that these findings may be explained in terms of evolutionary theory. Erotomania, accordingly, may be viewed as a pathological variant of a specific sexual strategy that evolved under selection pressures of the human environment of evolutionary adaptedness. The overt behavior is related to the pursuit of long‐term mating, its potentially beneficial effect on inclusive fitness of the individual, and disparate strategies of the sexes to ensure sexual fidelity of the potential partner. Therefore, the evolutionary approach provides a plausible explanation as to why forensically relevant erotomania prevails in men. The pathological process of delusional misinterpretation of perceived signals from the social environment itself may result from poor reality testing due to a failure of social meta‐cognition. The evolutionary perspective may provide additional insights into the nature of sex‐specific behaviors and may improve our understanding of forensically relevant behaviors. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of intracellular efficacies of azithromycin againstLeishmania majorinfection in human neutrophilsin vitro
Authors: Tanyuksel Mehmet , Bas A. Levent , Araz Engin , Aybay Cemalettin
Published: February 2003

Azithromycin is one of a new class of antibiotics known as azalides. Azithromycin has high tissue affinity and this feature is thought to be due to the presence of two basic tertiary amine groups.Leishmania major, one of the causative agents of cutaneous leishmaniosis, is an obligate intracellular parasite. In thisin vitrostudy, the potential anti‐leishmanial effect of azithromycin upon intracellular forms namely the amastigote ofL. majorin mice peritoneal macrophages was investigated.L. majorpromastigotes were propagated in RPMI‐1640 supplemented with 20% fetal calf serum in the log phase. The percentage of phagocytosis and microbiacidal activity of azithromycin on macrophages was assessed in the control and study groups by fluorescence microscopy, using acridine orange. Our results showed that at all the concentrations used (0.05, 0.1, 0.3, 0.6 μg ml−1) azithromycin had no inhibitory effect on the phagocytic capacity of mouse peritoneal macrophages. Although no significant difference was observed for leishmaniacidal activity between the study and the control groups at a concentration of 0.05 μg ml−1(p>0.05), a significant (p<0.05) increase in leishmaniacidal activity was detected at 0.1, 0.3 and 0.6 μg ml−1. As a result, azithromycin does not provide any contribution to the phagocytosis ofL. majorpromastigotes in macrophagesin vitro, but it increases the intracellular killing rates of amastigotes. These results suggest that it has a potential anti‐leishmanial effect, and may provide a significant advantage in the treatment of the disease. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of cobalt on the oxidative status in heart and aorta of streptozotocin‐induced diabetic rats
Authors: Yildirim Özlem , Büyükbingöl Zeliha
Published: February 2003

Effects of cobalt on the antioxidant status of control and streptozotocin diabetic rat heart and aorta were examined at the second, fourth and sixth week of treatment. Rats were divided into four groups: control, diabetic, control treated with cobalt chloride and diabetic treated with cobalt chloride. Diabetes was induced by tail vein injection of streptozotocin (STZ). Cobalt treatment groups were given 0.5 mM of CoCl2 in drinking water. The rats in both groups were further subdivided into three groups of six rats each. Rats in these subgroups were studied at 2‐week intervals up to 6 weeks. At the end of the experiment, all animals were sacrified by decapitation, heart and aorta samples were removed for determination of thiobarbituric acid reactive substance (TBARS) level and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH‐Px) activities. It was found that lipid peroxidation levels and antioxidant enzyme activities were increased in the streptozotocin‐induced diabetic rats at all times studied. Cobalt treatment of diabetic rats (0.5 mM in drinking water) resulted in attenuation of the increased levels of TBARS and antioxidant enzyme activities in heart and aorta. Thus, the effect of oral administration of cobalt at this dose during the early stage of experimental diabetes can be considered as a consequence of altered endogenous defence mechanisms in heart and aorta. Copyright © 2002 John Wiley & Sons, Ltd.
Role of latent heat in chiral symmetry breaking transition in the crystallization of 1,1′‐binaphthyl
Authors: Asakura Kouichi , Hayashi Masato , Osanai Shuichi
Published: February 2003

The influence of latent heat dissipated by the crystallization of 1,1′‐binaphthyl in its supercooled molten state on the chiral symmetry breaking transition was investigated. Temperature change in the crystallization system was monitored by infrared thermocamera. Temperature rise due to the dissipation of latent heat in the growing front of polycrystalline aggregate was about 2°C in an unstirred crystallization system. The melting point of racemic mixture and racemic compound of 1,1′‐binaphthyl is 145°C and 158°C, respectively. The latent heat generated by the crystallization could thus change the crystallization behavior when the initial temperature of the melt was slightly lower than 145°C. The temperature change in both unstirred and stirred crystallization systems was monitored. In the stirred crystallization system, even in the case when the initial temperature of the melt was about 2°C lower than 145°C, the temperature rose by about 4°C immediately after the onset of crystallization. This indicates that the role of stirring as the critical parameter for the chiral symmetry breaking transition is not only to clone the chiral crystals but also to enhance the dissipation of latent heat due to secondary nucleation. Chirality 15:238–241, 2003. © 2003 Wiley‐Liss, Inc.
Chiral reagents for the determination of enantiomeric excess and absolute configuration using NMR spectroscopy
Authors: Wenzel Thomas J. , Wilcox James D.
Published: February 2003

Recent advances in the development of chiral derivatizing and solvating agents that facilitate the determination of enantiomeric excess and absolute configuration are reviewed. These include metal‐containing species, host–guest systems, donor–acceptor compounds, and liquid crystal discriminating agents. In the aggregate, these reagents can be used to analyze a wide range of compound classes. Chirality 15:256–270, 2003. © 2003 Wiley‐Liss, Inc.
Evaluation of absolute configuration of naphthylphenyl‐substituted oligosilanes by CD exciton chirality method
Authors: Oh Hyun‐Shik , Imae Ichiro , Kawakami Yusuke
Published: February 2003

Absolute configurations of methylnaphthylphenyl‐substituted oligosilanes, MeNpPhSi*SiMeR1R2[2(R1, R2=Me),3(R1=Me, R2=Ph),4(R1, R2=Ph), and5(R1=Me, R2=SiMe3)] were predicted by circular dichroism (CD) exciton chirality method. The σ–π conjugation effect of oligosilylene units (σ‐linkage) with π‐electron systems caused an intense red‐shift of1La,Phtransition band of the oligosilanes as shown in UV/VIS and made it possible to observe clear CD exciton chirality between the two aromatic chromophores on chiral silicon atom. Chirality 15:231–237, 2003. © 2003 Wiley‐Liss, Inc.
Crosslinking of biological tissues using genipin and/or carbodiimide
Authors: Sung Hsing‐Wen , Chang Wen‐Hisang , Ma Chiun‐Yuang , Lee Meng‐Horng
Published: February 2003

The study was to investigate the crosslinking characteristics, mechanical properties, and resistance against enzymatic degradation of biological tissues after fixation with genipin (a naturally occurring crosslinking agent) and/or carbodiimide. Fresh tissue was used as a control. It was found that both genipin and carbodiimide are effective crosslinking agents for tissue fixation and genipin crosslinking is comparatively slower than carbodiimide crosslinking. Additionally, tissue fixation in genipin and/or carbodiimide may produce distinct crosslinking structures. Carbodiimide may form intrahelical and interhelical crosslinks within or between tropocollagen molecules, whereas genipin may further introduce intermicrofibrillar crosslinks between adjacent collagen microfibrils. The stability (denaturation temperature and resistance against enzymatic degradation) of the fixed tissue is mainly determined by its intrahelical and interhelical crosslinks. In contrast, intermicrofibrillar crosslinks significantly affect the mechanical properties (tissue shrinkage during fixation, tensile strength, strain at break, and ruptured pattern) of the fixed tissue. Moreover, the degree of enzymatic degradation of the fixed tissue may be influenced by three factors: the availability, to the enzyme, of recognizable cleavage sites, the degree of crosslinking, and the extent of helical integrity of tropocollagen molecules in tissue. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 427–438, 2003
Neural differentiation of midbrain cells on various protein‐immobilized polyethylene films
Authors: Nakaoka Ryusuke , Tsuchiya Toshie , Nakamura Akitada
Published: February 2003

The effect of surface modification of polyethylene (PE) film on differentiation of midbrain (MB) cells obtained from rat embryos was determined by their micromass culture system. When cultured on untreated PE film, cell differentiation was suppressed to approximately two‐thirds of that observed in a control culture dish. On the contrary, type I collagen‐immobilized PE film increased differentiated foci of the MB cells more than did the untreated PE film. RGDS (Arg‐Gly‐Asp‐Ser) peptide immobilization onto PE film resulted in almost the same differentiation activity as the collagen immobilized PE film. Bovine serum albumin (BSA) immobilization onto PE film enhance the differentiation activity more than did the untreated PE film, but not up to the levels of collagen‐ and RGDS‐immobilized PE. The number of differentiated foci of the MB cells on untreated PE film were increased by the addition of the condition medium prepared from the collagen‐immobilized PE film. However, the number of foci was not increased by the addition of other condition media obtained from control dish, untreated, BSA‐, and RGDS‐immobilized PE. On the other hand, none of these condition media enhanced a differentiation of the neuronal cell line of PC12 cells, suggesting that some factors effectively differentiate midbrain cells, composed of neuronal epithelial and mesenchymal cells, but not the PC12 cells secreted in the condition media prepared from collagen‐immobilized PE. In addition, it is probable that neural growth factor was not secreted in these condition media, which could not induce the differentiation of PC12 cells. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 439–446, 2003
Biosynthetic response of passaged chondrocytes in a type II collagen scaffold to mechanical compression
Authors: Lee C. R. , Grodzinsky A. J. , Spector M.
Published: February 2003

To investigate the potential utility of mechanical loading in articular cartilage tissue engineering, porous type II collagen scaffolds seeded with adult canine passaged chondrocytes were subjected to static and dynamic compressions of varying magnitudes (0–50% static strain) and durations (1–24 h), and at different times during culture (2–30 days postseeding). The effects of mechanical compression on the biosynthetic activity of the chondrocytes were evaluated by measuring the amount of 3H‐proline‐labeled proteins and 35S‐sulfate‐labeled proteoglycans that accumulated in the cell‐scaffold construct and was released to the medium during the loading period. Similar to published results on loading of articular cartilage explants, static compression decreased protein and proteoglycan biosynthesis in a time‐ and dose‐dependent manner (each p < 0.005), and selected dynamic compression protocols were able to increase rates of biosynthesis (p < 0.05). The main difference between the results seen for this tissue engineering system and cartilage explants was in the amount of newly synthesized matrix molecules that accumulated within the construct under dynamic loading, with less accumulating in the type II collagen scaffold. In summary, the general biosynthetic response of passaged chondrocytes in the porous type II collagen scaffolds is similar to that seen for chondrocytes in their native environment. Future work needs to be directed to modifications of the cell‐seeded construct to allow for the capture of the newly synthesized matrix molecules by the scaffold. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 64A: 560–569, 2003
Early up‐regulation of chemokine expression in fulminant hepatic failure
Authors: Leifeld Ludger , Dumoulin Franz‐Ludwig , Purr Ingvill , Janberg Katrin , Trautwein Christian , Wolff Martin , Manns Michael Peter , Sauerbruch Tilman , Spengler Ulrich
Published: February 2003

CC‐chemokines recruit and activate macrophages and T lymphocytes, the major components of inflammatory infiltrates in fulminant hepatic failure (FHF). To analyse the role of CC‐chemokines in the pathogenesis of FHF, this study examined serum levels and intrahepatic expression of MCP‐1, MIP‐1α, MIP‐1β, and RANTES in the livers and sera of patients with FHF and controls by ELISA, immunohistochemistry, and competitive RT‐PCR. Serum levels and intrahepatic expression of all chemokines studied in FHF exceeded the levels in chronic liver diseases and normal controls. Distinct patterns of expression of each chemokine were noted on Kupffer cells, sinusoidal endothelial cells, hepatocytes, lymphocytes, and bile ducts. Intrahepatic chemokine expression correlated closely with the extent of infiltration by macrophages and T lymphocytes (r = 0.65–0.95, p < 0.001). The functional relationship between intrahepatic chemokine release and infiltration was confirmed in chemotaxis assays by inhibiting chemotaxis induced by homogenates of liver tissue obtained from FHF patients with neutralizing MCP‐1, MIP‐1α, MIP‐1β, and RANTES antibodies. The time course of CC‐chemokine release was studied in the concanavalin A and the galactosamine/LPS mouse models of FHF. In both models, intrahepatic chemokine up‐regulation occurred as an early event prior to hepatic infiltration and liver damage. The data indicate that an abundant intrahepatic release of CC‐chemokines is an early and pivotal step in the pathogenesis of FHF. Copyright © 2003 John Wiley & Sons, Ltd.
α‐Actin isoform distribution in normal and failing human heart: a morphological, morphometric, and biochemical study
Authors: Suurmeijer Albert JH , Clément Sophie , Francesconi Arianna , Bocchi Leonardo , Angelini Annalisa , Van Veldhuisen Dirk J , Spagnoli Luigi Giusto , Gabbiani Giulio , Orlandi Augusto
Published: February 2003

We investigated the distribution of α‐skeletal, α‐cardiac, and α‐smooth muscle actin isoforms in human heart during development, hypertrophy, and failure. At 20 weeks of fetal life, α‐skeletal actin was localized in a small proportion of subendocardial and papillary muscle cardiomyocytes. At this gestation time, diffuse α‐cardiac actin staining was observed, associated with focal expression of α‐smooth muscle actin. In normal adult subjects, α‐skeletal actin positive cardiomyocytes were distributed in a transmural gradient with the highest proportion located subendocardially. In myocardial hypertrophy and cardiomyopathies, the amount of α‐skeletal actin was increased and diffuse staining was seen in all layers of ventricular myocardium, with the exception of idiopathic dilated cardiomyopathies. Cardiomyocytes were negative for α‐smooth muscle actin in all pathological situations studied. As expected, fibroblasts in post‐infarct scars expressed α‐smooth muscle actin and transforming growth factor‐β1 but, surprisingly, were negative for these proteins in interstitial fibrosis. Our results demonstrate that increased expression of α‐skeletal actin in the diseased human heart is associated with increased myocyte stretch, increased wall stress, and pressure overload, but not with idiopathic dilated cardiomyopathies. They also suggest that fibrotic changes develop with different mechanisms in scars versus interstitial fibrosis. Copyright © 2003 John Wiley & Sons, Ltd.
Functional groups expressed as graphs extracted from the Laplacian of the electron density
Authors: Popelier Paul L. A. , Burke James , Malcolm Nathaniel O. J.
Published: February 2003

The valence charge concentration shell, as determined by the Laplacian of the electron density, is used as a source of quantum topological graphs, called L‐graphs. A considerable number of such graphs are extracted from theab initiowave functions of 31 molecules calculated at the B3LYP/6‐311+G(2d,p)//B3LYP/6‐311+G(2d,p)level, covering common functional groups in organic chemistry. We show how L‐graphs can be constructed from a largely transferable subgraph called atomic L‐graph. We investigate the topological stability of the L‐graphs as a function of the basis set. Reliable and consistent atomic L‐graphs are only obtained with basis sets of triple‐zeta quality or higher. The recurrence of invariant motifs or subgraphs in the L‐graphs enables the isolation of 16 atomic L‐graphs. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003
Pain Practices: A Cross-Canada Survey of Pediatric Oncology Centers
Authors: Ellis Jacqueline A. , McCarthy Patricia , Hershon Linda , Horlin Rosemary , Rattray Marion , Tierney Sally
Published: February 2003

Before implementing a pain education program, the Canadian Association of Nurses in Oncology conducted a national survey on cancer pain management. The survey focused primarily on adult cancer pain and a second survey was undertaken to describe the supports in place across Canada for best practice pediatric cancer pain management. Twenty-eight pediatric cancer centers re sponded to a survey that was composed of 48 questions about the types of supports that are in place related to pain assessment, management, and pain- related staff and family education. Results of the survey indicated that, for the most part, children have access to the components of best practice pain manage ment. In addition, areas of strength and areas that need to be further developed
Songwriting and Digital Video Production Interventions for Pediatric Patients Undergoing Bone Marrow Transplantation, Part II: An Analysis of Patient-Generated Songs and Patient Perceptions Regarding Intervention Efficacy
Authors: Robb Sheri L. , Ebberts Allison G.
Published: February 2003

Part I of this exploratory case study examined patient anxiety levels and depres sive symptoms according to phase of bone marrow transplantation (BMT). The second part of this study examines more qualitative outcomes of the music therapy intervention. Purposes of this part of the study included: (1) to examine the lyrical content of patient-generated songs and (2) to compare patient percep tions regarding the effectiveness of a 6-week music condition with a no-music contact condition. Six pediatric BMT patients participated in the study. Three participants experienced the music condition and three participants experienced the no-music contact condition. Both conditions consisted of six, 1-hour sessions that occurred over a 3-week period. Content analysis of patient-generated songs revealed expression of issues related to the following themes: hope, positive coping, appreciation, mental status, control, time, bewilderment, treatment, and diagnosis. Examination of patient-generated songs provided insight into each patient's experience with transplantation and the coping strategies used during treatment. Outcomes from a poststudy questionnaire are summarized.
Effects of age and sex on the disposition of retigabine
Authors: Hermann Robert , Ferron Geraldine M. , Erb Katharina , Knebel Norbert , Ruus Peter , Paul Jeffrey , Richards Lyette , Cnota Hans‐Peter , Troy Steven
Published: February 2003

Background

The novel antiepileptic drug retigabine is the first selective M‐current potassium channel opener for KCNQ2/3 and KCNQ3/5 channels. Retigabine undergoes phase II metabolism (N‐glucuronidation, acetylation) exclusively and renal excretion.

Objective

Our objective was to evaluate the effects of age and sex on the pharmacokinetics of retigabine.

Methods

Healthy young (age range, 18‐40 years) and elderly (age range, 66‐81 years) white subjects (12 men and 12 women in each group) received a single 200‐mg oral dose of retigabine. After dosing, blood was collected over a 72‐hour period to determine plasma concentrations of retigabine and its acetylated metabolite, AWD21‐360. Pharmacokinetics was compared for age group and sex by ANOVA.

Results

In young men, retigabine was rapidly absorbed, with the maximum concentration occurring within 2 hours, and was eliminated with an apparent clearance of 0.67 L × h−1 × kg−1 and a mean terminal half‐life of 8.5 hours. Subjects were similarly exposed to AWD21‐360. Compared with young men, young women had higher retigabine maximum concentration (56%) and exposure (20%) but similar clearance (0.68 L × h−1 × kg−1); these differences were related to differences in body weight. Although maximum concentration was similar in elderly subjects, retigabine elimination was slower (30% lower apparent clearance normalized for weight), resulting in higher exposure (42%) and a longer half‐life (30%). Because phase II metabolism is scarcely affected by age, these differences may be related to the known decline of renal function with age.

Conclusions

Although there are no substantial sex‐related differences in the disposition of retigabine, a relevant decrease in clearance resulting in higher exposure occurs in elderly patients. The results suggest that decline of renal function with age may account for some of the observed changes.

Clinical Pharmacology & Therapeutics (2003) 73, 61–70; doi: 10.1067/mcp.2003.12
Activation of IP3‐Protein Kinase C‐α Signal Transduction Pathway Precedes the Changes of Plasma Cholesterol, Hepatic Lipid Metabolism and Induction of Low‐Density Lipoprotein Receptor Expression in 17‐β‐Oestradiol‐Treated Rats
Authors: Marino M. , Distefano E. , Pallottini V. , Caporali S. , Bruscalupi G. , Trentalance A.
Published: February 2003

The intracellular concentration of cholesterol is regulated by the balance between endogenous synthesis and exogenous uptake. Oestrogens have been reported to be involved in the physiological regulation of cellular cholesterol content. Relevant reports have focused on long‐term responses and there is a lack of information about the relationship between the timing of the oestrogen effect and the regulation of cholesterol homeostasis. The aim of this work has been to set up a systematic picture of the short‐term effects induced by oestrogen on hepatic lipid metabolism in vivo and the involvement of some relevant signal transduction pathways. At intervals after oestrogen administration (30 min to 6 h), oestrogen receptor expression and changes in liver cAMP, IP3 and protein kinase C‐α (PKC‐α) were followed. Changes in the expression of the low density lipoprotein receptor at mRNA and protein levels, and of hydroxy‐methyl‐glutaryl‐CoA reductase activity have been verified. At the same time, the content of hepatic cholesterol, ubiquinone and dolichol and of plasma cholesterol have been determined. Changes of rab 5 and rab 8, small GTP‐binding prenylated proteins involved in the transfer of neosynthesised proteins through the cell, have been also checked. In vivo treatment with oestradiol produced no change in cyclic AMP but a rapid increase in IP3, increased PKC‐α localisation on the membranes and enhanced expression of the low density lipoprotein receptor in the liver occurred. PKC inhibition completely prevented any increase in low density lipoprotein receptor mRNA in isolated and perfused rat liver. Early changes of ubiquinone and dolichol content and a later reduction in hepatic hydroxy‐methyl‐glutaryl‐CoA reductase activity and plasma cholesterol content were also detectable. A functional role of the IP3 ‐protein kinase C‐α pathway in the induction of the low density lipoprotein receptor is suggested.
Interstitial Fluid Pressure Surrounding Rat Mesenteric Venules During Changes in Fluid Filtration
Authors: Kajimura M. , Wiig H. , Reed R. K. , Michel C. C.
Published: February 2003

The interstitial fluid pressure (Pisf) has been measured in the exposed superfused mesenteries of anaesthetised rats using the micropipette servo‐null technique. When mesenteries were superfused with Ringer‐Locke solutions, Pisf was close to atmospheric pressure with mean ± S.E.M. values of ‐0.46 ± 0.14 cmH2O (n= 22). Superfusing with paraffin oil did not alter Pisf significantly, but Pisf could be lowered considerably by removing fluid from the upper surface of the mesentery. Measurements of Pisf were also made in the tissues immediately outside mesenteric venules as the pressure inside these vessels and the filtration of fluid through their walls was varied. No significant changes in perivascular Pisf could be detected even though the intravascular pressure varied from 20 to 70 cmH2O. Addition of histamine or the mast cell degranulating agent compound 48/80 to the superfusate had no significant effect on Pisf. The findings are relevant to experiments on the permeability of single perfused mesenteric microvessels. They strengthen the assumption, which is made in these studies, that Pisf is close to atmospheric pressure and does not change significantly with changes in the filtration and reabsorption of fluid through the vessel walls.
Effects of Prior Exercise and Recovery Duration on Oxygen Uptake Kinetics During Heavy Exercise in Humans
Authors: Burnley Mark , Doust Jonathan H. , Carter Helen , Jones Andrew M.
Published: February 2003

Prior heavy exercise (above the lactate threshold, LT) reduces the amplitude of the pulmonary oxygen uptake (V̇O2) slow component during heavy exercise, yet the precise effect of prior heavy exercise on the phase II V̇O2 response remains to be established. This study was designed to test the hypotheses that (1) prior heavy exercise increases the amplitude of the phase II V̇O2 response independently of changes in the baseline V̇O2 value and (2) the effect of prior exercise depends on the amount of external work done during prior exercise, irrespective of the intensity of the prior exercise. Nine subjects performed two 6 min bouts of heavy cycling exercise separated by 6 min baseline pedalling recovery (A), two 6 min heavy exercise bouts separated by 12 min recovery (6 min rest and 6 min baseline pedalling, B), and a bout of moderate exercise (below the LT) in which the same amount of external work was performed as during the prior heavy exercise, followed by 6 min heavy exercise (C). In both tests A and B, prior heavy exercise significantly increased the absolute V̇O2 amplitude at the end of phase II (by ∼150 ml min−1), and reduced the amplitude of the V̇O2 slow component by a similar amount. Following 12 min of recovery (B), baseline V̇O2, but not blood [lactate], had returned to pre‐exercise levels, indicating that these effects occurred independently of changes in baseline V̇O2. Prior moderate exercise (C) had no effect on either the V̇O2 or blood [lactate] responses to subsequent heavy exercise. The V̇O2 response to heavy exercise was therefore dependent on the intensity of prior exercise, and the effects on the amplitudes of the phase II and slow V̇O2 components persisted for at least 12 min following prior heavy exercise.
Mechanical Control of Extracellular Space in Rabbit Atria: An Intimate Modulator of the Translocation of Extracellular Fluid and Released Atrial Natriuretic Peptide
Authors: Woo Cho Kyung , Jeong Lee Sook , Fu Wen Jin , Hee Kim Suhn , Hwan Seul Kyung , Sub Lee Ho
Published: February 2003

We have previously shown that extracellular fluid (ECF) is translocated by atrial contraction. Following on from this finding we have proposed a two‐step sequential mechanism for the regulation of stretch‐activated secretion of atrial natriuretic peptide (ANP): myocytic release of ANP into the surrounding paracellular space followed by the translocation of ECF with the released ANP into the bloodstream. This latter step is induced by atrial contraction, and is therefore controlled by atrial workload. However, the mechanism that regulates the changes in translocation of the ECF has not been defined. To define the relationship between the atrial workload, ECF translocation, size of the extracellular space (ECS) and ANP secretion, experiments have been performed in isolated perfused beating rabbit atria. Atrial workload, transendocardial translocation of the ECF and the secretion of ANP were quantified. Changes in the size of the atrium and the ECS were determined by a newly developed methodology in the beating atria. Atrial workload determined the translocation of the ECF and released ANP with waning of the translocation at higher myocardial workloads. Atrial workload inversely determined the size of the atrium and the ECS. The latter directly determined the translocation of the ECF in terms of atrial workload. From these data we suggest that the size of the ECS is an intimate modulator of the translocation of the ECF and released ANP, and that the phenomenon of waning of the transendocardial translocation that appeared at higher atrial workloads is closely related to the shrinkage of the ECS.
Hyperprolactinaemia During Prolonged Exercise in the Heat: Evidence for a Centrally Mediated Component of Fatigue in Trained Cyclists
Authors: Pitsiladis Y. P. , Strachan A. T. , Davidson I. , Maughan R. J.
Published: February 2003

Several lines of evidence suggest that central serotoninergic neurons may mediate fatigue signals during prolonged exercise. In this study we examined the effects of diet and ambient temperature on peripheral modulators and indices of serotoninergic function and their relationship to exercise performance. Six well‐trained cyclists participated, in randomised order, in two diet and exercise regimens each lasting 8 days and comprising four cycle tests to exhaustion at 70% of maximum oxygen uptake. On days 1 and 5, subjects exercised to exhaustion to deplete muscle glycogen. For 3 days after the first depletion trial a diet providing 10% of energy in the form of carbohydrate (CHO) was consumed (low CHO), and for 3 days after the second depletion trial a diet providing 80% (high CHO) of energy as CHO was consumed, and each diet was followed by a performance trial at the same ambient temperature, either 10 °C or 30 °C (days 4 and 8). This schedule was repeated after 1 week, but performance trials were carried out at the other ambient temperature. In the cold, cycling time increased (P < 0.01) from 89.2 (78.0‐129.5) min (median (range)) in the low CHO trial to 158.2 (116.9‐165.6) min in the high CHO trial. In the heat, cycling time increased from 44.0 (31.8‐51.4) min in the low CHO trial to 53.2 (50.2‐82.2) min on the high CHO trial (P = 0.02). The serum prolactin (Prl) concentration was higher at exhaustion during the two trials in the heat than in the two trials in the cold. Serum Prl levels were unrelated to the purported peripheral modulators of serotoninergic function (plasma concentrations of total tryptophan (Trp), free Trp, branched‐chain amino acids (BCAAs), free Trp/BCAA ratio and total Trp/BCAA ratio) but were significantly related to the rectal temperatures measured during the two trials in the heat. This finding provides indirect evidence that the serotoninergic system may be involved in fatigue during exercise under conditions of heat stress.
Response of Skeletal Muscle Mitochondria to Hypoxia
Authors: Hoppeler Hans , Vogt Michael , Weibel Ewald R. , Flück Martin
Published: February 2003

This review explores the current concepts relating the structural and functional modifications of skeletal muscle mitochondria to the molecular mechanisms activated when organisms are exposed to a hypoxic environment. In contrast to earlier assumptions it is now established that permanent or long‐term exposure to severe environmental hypoxia decreases the mitochondrial content of muscle fibres. Oxidative muscle metabolism is shifted towards a higher reliance on carbohydrates as a fuel, and intramyocellular lipid substrate stores are reduced. Moreover, in muscle cells of mountaineers returning from the Himalayas, we find accumulations of lipofuscin, believed to be a mitochondrial degradation product. Low mitochondrial contents are also observed in high‐altitude natives such as Sherpas. In these subjects high‐altitude performance seems to be improved by better coupling between ATP demand and supply pathways as well as better metabolite homeostasis. The hypoxia‐inducible factor 1 (HIF‐1) has been identified as a master regulator for the expression of genes involved in the hypoxia response, such as genes coding for glucose transporters, glycolytic enzymes and vascular endothelial growth factor (VEGF). HIF‐1 achieves this by binding to hypoxia response elements in the promoter regions of these genes, whereby the increase of HIF‐1 in hypoxia is the consequence of a reduced degradation of its dominant subunit HIF‐1α. A further mechanism that seems implicated in the hypoxia response of muscle mitochondria is related to the formation of reactive oxygen species (ROS) in mitochondria during oxidative phosphorylation. How exactly ROS interfere with HIF‐1α as well as MAP kinase and other signalling pathways is debated. The current evidence suggests that mitochondria themselves could be important players in oxygen sensing.