bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of a lysK gene as an argE homolog in Thermus thermophilus HB27
Authors: Miyazaki Junichi , Kobashi Nobuyuki , Fujii Tomoyuki , Nishiyama Makoto , Yamane Hisakazu
Published: October 2002

We conducted a chromosome walk to obtain a DNA fragment downstream of lysJ and found an argE homolog in a putative operon composed of lysJ–orfC–orfD–argE homologs. A knockout mutant of the argE homolog showed significantly slow growth on a minimal medium, and the growth was markedly improved by addition of lysine. We therefore termed this gene lysK. Purified LysK protein has deacetylating activities for both N
2‐acetyllysine and N
2‐acetylornithine at almost equal efficiency. These results suggest that lysK which may share an ancestor with argE functions not only for the lysine biosynthesis, but also for arginine biosynthesis in Thermus thermophilus.
Conformational change and destabilization of cataract γC‐crystallin T5P mutant
Authors: Fu Ling , Liang Jack J.-N.
Published: October 2002

Human lens γC‐crystallin and T5P mutant were cloned, and their biophysical properties and thermodynamic stability were studied. CRYGC (T5P) is one of the many γ‐crystallin mutant genes for autosomal dominant congenital cataracts. This mutation is associated with Coppock‐like cataract, and has the phenotype of a dust‐like opacity of the fetal lens nucleus. During cloning and overexpression, the majority of T5P mutant was found in the inclusion body. This property is unique among the many cataract γ‐crystallin mutant genes. It is thus worthwhile to study what factors contribute to this unique property of γC‐crystallin. One possibility is changes in conformation and stability, which can be studied using spectroscopic measurements. In this study, conformational change was studied by circular dichroism and fluorescence measurements, and conformational stability was determined by thermal unfolding probed by Trp fluorescence and time‐dependent light scattering. The T5P mutation obviously changes conformation and decreases conformational stability.
Identification of genes expressed preferentially in the honeybee mushroom bodies by combination of differential display and cDNA microarray1
Authors: Takeuchi Hideaki , Fujiyuki Tomoko , Shirai Kenichi , Matsuo Yuko , Kamikouchi Azusa , Fujinawa Yumi , Kato Azusa , Tsujimoto Atsumi , Kubo Takeo
Published: October 2002

To clarify the molecular basis underlying the neural function of the honeybee mushroom bodies (MBs), we identified three genes preferentially expressed in MB using cDNA microarrays containing 480 differential display‐positive candidate cDNAs expressed locally or differentially, dependent on caste/aggressive behavior in the honeybee brain. One of the cDNAs encodes a putative type I inositol 1,4,5‐trisphosphate (IP3) 5‐phosphatase and was expressed preferentially in one of two types of intrinsic MB neurons, the large‐type Kenyon cells, suggesting that IP3‐mediated Ca2+ signaling is enhanced in these neurons.
Genome‐wide studies on the nuclear PDR3‐controlled response to mitochondrial dysfunction in yeast
Authors: Devaux Frédéric , Carvajal Elvira , Moye-Rowley Scott , Jacq Claude
Published: October 2002

Gain‐of‐function mutations in the transcription factors Pdr1p and Pdr3p lead to the up‐regulation of genes controlling plasma membrane properties. Pdr3p is involved in a retrograde response in which mitochondrial dysfunctions activate PDR5, a gene encoding an ABC membrane transporter. We carried out genome‐wide analyses of the PDR3‐controlled genes activated by the deletion of the mitochondrial DNA. We present evidence showing that PDR1 does not interfere with this PDR3 response. We also showed that the mitochondrially activated PDR3 response is highly sensitive to both yeast strain variations and carbon sources. These observations explain the apparent discrepancies in published studies and better describe the connections between the mitochondrial state and plasma membrane properties.
Analysis of respiratory mutants reveals new aspects of the control of glycogen accumulation by the cyclin‐dependent protein kinase Pho85p
Authors: Wilson Wayne A , Wang Zhong , Roach Peter.J
Published: October 2002

The PHO85 gene of Saccharomyces cerevisiae encodes a cyclin‐dependent protein kinase that can interact with 10 different cyclins (Pcls). In conjunction with Pcl8p and Pcl10p, Pho85p phosphorylates and regulates glycogen synthase. Respiratory‐deficient strains, such as coq3 mutants, have reduced glycogen stores and contain hyperphosphorylated and inactive glycogen synthase. We show here that pho85 coq3 mutants have dephosphorylated and active glycogen synthase yet do not maintain glycogen reserves. In contrast, deletion of PCL8 and PCL10 in the coq3 mutant background partially restores glycogen accumulation. This suggested the existence of inputs from Pho85p into glycogen storage, independent of Pcl8p and Pcl10p, and acting antagonistically.
Troponin I converts the skeletal muscle ryanodine receptor into a rectifying calcium release channel
Authors: Varsányi Magdolna , Sárközi Sándor , Szegedi Csaba , Herzog Anke , Jóna István
Published: October 2002

The goal of our present studies has been to find novel ryanodine receptor (RyR1) interacting polypeptides that modulate the channel activity from the luminal side of RyR1. Using K+ as charge carrier for recording of single channel events here we demonstrate a very unexpected observation that troponin I substantially alters RyR's gating behavior, and that RyR1 in association with troponin I becomes a rectifying Ca2+ release channel. Troponin I rapidly locks the RyR1 in a non‐conducting state only at a negative holding potential, and only when applied to the luminal side; switching to a positive holding potential results in the channel returning to its original activity, immediately. A hypothesis is proposed to account for how an intraluminally located, positively charged molecule might function as a RyR1 regulator under physiological conditions.
Intracellular calcium mobilization induces period genes via MAP kinase pathways in NIH3T3 cells
Authors: Oh-hashi Kentaro , Naruse Yoshihisa , Tanaka Masaki
Published: October 2002

Mammalian period genes have a pivotal role in generating circadian rhythms and are rapidly induced by several stimuli in mammalian cells. In the present study, we revealed that treatment with thapsigargin significantly induced transcripts of mouse period 1 and 2 (mPer1 and mPer2) but not mPer3 among circadian related genes in NIH3T3 cells. Thapsigargin‐induced mPer1 and mPer2 mRNA expressions took distinct signaling pathways from protein kinase C and cAMP, but were partially inhibited by inhibitors of MEK1 and p38 mitogen‐activated protein kinase, respectively. Thus, the present study suggested that intracellular calcium is one of multiple signaling stimuli triggering mPer gene expression in NIH3T3 cells.
The Fluorosome™ technique for investigating membrane on‐ and off‐loading of drugs by β‐CD and sonicated SUV
Authors: Fix Marina , Melchior Donald L
Published: October 2002

The application of the Fluorosome technique to test drug delivery systems is described. Fluorosomes, egg phosphatidylcholine liposomes with bilayer embedded fluorophores, were employed to investigate the ability of sonicated small unilamellar vesicles (sSUV) and β‐cyclodextrins (β‐CD) to deliver drugs into or extract drugs from the fluorosome's phospholipid bilayer. The addition of phloretin to a fluorosome suspension resulted in fluorescence reduction reflecting phloretin entering the bilayer and quenching fluorophore fluorescence. Subsequent addition of sSUV to phloretin pretreated fluorosomes showed an increase in fluorescence reflecting phloretin extraction from the fluorosome membrane. Sequential additions of β‐estradiol loaded β‐CD to fluorosomes as well as the addition of β‐estradiol alone resulted in fluorescence reduction due to β‐estradiol insertion into the membrane. Further addition of pure β‐CD resulted in a fluorescence increase indicating β‐estradiol extraction from the fluorosome membrane.
Mining functional relationships in feature subspaces from gene expression profiles and drug activity profiles
Authors: Bao Lei , Guo Tao , Sun Zhirong
Published: October 2002

In an effort to determine putative functional relationships between gene expression patterns and drug activity patterns of 60 human cancer cell lines, a novel method was developed to discover local associations within cell line subsets. The association of drug–gene pairs is an explorative way of discovering gene markers that predict clinical tumor sensitivity to therapy. Nine drug–gene networks were discovered, as well as dozens of gene–gene and drug–drug networks. Three drug–gene networks with well studied members were discussed and the literature shows that hypothetical functional relationships exist. Therefore, this method enables the gathering of new information beyond global associations.
A comparative structural and functional analysis of cytochrome cM, cytochrome c6 and plastocyanin from the cyanobacterium Synechocystis sp. PCC 6803
Authors: Molina-Heredia Fernando P , Balme Alexis , Hervás Manuel , Navarro José A , De la Rosa Miguel A
Published: October 2002

Cytochrome c
M is a new c‐class photosynthetic haem protein whose physiological role is still unknown. It has been proposed previously that cytochrome c
M can replace cytochrome c
6 and plastocyanin in transferring electrons between the two membrane complexes cytochrome b
6–f and photosystem I in organisms growing under stress conditions. The experimental evidence herein provided allows us to discard such a hypothesis. We report a procedure to overexpress cytochrome c
M from the cyanobacterium Synechocystis sp. PCC 6803 in Escherichia coli cells in mg quantities. This has allowed us to perform a comparative laser flash‐induced kinetic analysis of photosystem I reduction by the three metalloproteins from Synechocystis. The bimolecular rate constant for the overall reaction is up to 100 times lower with cytochrome c
M than with cytochrome c
6 or plastocyanin. In addition, the redox potential value and surface electrostatic potential distribution of cytochrome c
M are quite different from those of cytochrome c
6 and plastocyanin. These findings strongly indicate that cytochrome c
M cannot be recognised by and interact with the same redox partners as the other two metalloproteins.
Selenoprotein W is a glutathione‐dependent antioxidant in vivo
Authors: Jeong Dae-won , Kim Tae Soo , Chung Youn Wook , Lee Byeong Jae , Kim Ick Young
Published: October 2002

The function of selenoprotein W (Se‐W) was investigated by cloning the corresponding cDNA from mouse brain and expressing it in CHO cells and H1299 human lung cancer cells. Overexpression of Se‐W markedly reduced the sensitivity of both cell lines to H2O2 cytotoxicity. The intracellular peroxide concentration of the transfected cells was lower than that of the parental cells in the absence or presence of extracellular H2O2. The resistance to oxidative stress conferred by Se‐W was dependent on glutathione. Expression of Se‐W mutants in which selenocysteine‐13 or cysteine‐37 was replaced by serine did not confer resistance to H2O2, implicating these residues in the antioxidant activity of Se‐W in vivo.
Oxygen reduction by cellobiose oxidoreductase: the role of the haem group
Authors: Mason Maria G. , Wilson Michael T. , Ball Andrew , Nicholls Peter
Published: October 2002

We have used optical and electron paramagnetic spectroscopy to study the flavohaem enzyme cellobiose oxidoreductase (CBOR) from Phanerochaete chrysosporium. We have examined redox cycles of the enzyme in which the oxidation of cellobiose to cellobionolactone is coupled to the reduction of oxygen. During turnover flavin can reduce oxygen with one electron to produce superoxide or two electrons to produce hydrogen peroxide. Addition of superoxide dismutase significantly extended the time courses of these cycles, slowing the re‐oxidation rate of both cofactors. Addition of catalase also affected the haem time course, but to a lesser extent. Experiments in which superoxide was generated in the reaction mixture showed that this radical greatly enhanced the rate of haem re‐oxidation. From these results we propose a mechanism in which reactive oxygen species generation by CBOR flavin subsequently re‐oxidises CBOR haem. We discuss this mechanism in relationship to the biological function of this enzyme, namely lignocellulose degradation.
Evidence for glucose‐6‐phosphate transport in rat liver microsomes
Authors: Gerin Isabelle , Van Schaftingen Emile
Published: October 2002

The existence of glucose‐6‐phosphate transport across the liver microsomal membrane is still controversial. In this paper, we show that S3483, a chlorogenic acid derivative known to inhibit glucose‐6‐phosphatase in intact microsomes, caused the intravesicular accumulation of glucose‐6‐phosphate when the latter was produced by glucose‐6‐phosphatase from glucose and carbamoyl‐phosphate. S3483 also inhibited the conversion of glucose‐6‐phosphate to 6‐phosphogluconate occurring inside microsomes in the presence of electron acceptors (NADP or metyrapone). These data indicate that liver microsomal membranes contain a reversible glucose‐6‐phosphate transporter, which furnishes substrate not only to glucose‐6‐phosphatase, but also to hexose‐6‐phosphate dehydrogenase.
Fusion of alphaviruses with liposomes is a non‐leaky process
Authors: Smit Jolanda M , Li Gang , Schoen Pieter , Corver Jeroen , Bittman Robert , Lin Ke-Chun , Wilschut Jan
Published: October 2002

It has been reported that low‐pH‐induced fusion of influenza virus with liposomes results in rapid and extensive release of both low‐ and high‐molecular‐weight substances from the liposomes [Günther‐Ausborn et al., J. Biol. Chem. 270 (1995) 29279–29285; Shangguan et al., Biochemistry 35 (1996) 4956–4965]. Here, we demonstrate retention of encapsulated water‐soluble compounds during fusion of Semliki Forest virus (SFV) or Sindbis virus with liposomes at low pH. Under conditions allowing complete fusion of the liposomes, a limited fluorescence dequenching of liposome‐encapsulated calcein was observed, particularly for SFV. Also, radioactively labeled inulin or sucrose were largely retained. Freezing and thawing of the viruses in the absence of sucrose resulted in an enhanced leakiness of fusion. These results support the notion that the alphavirus fusion event per se is non‐leaky and may well involve a discrete hemifusion intermediate.
The vitronectin binding area of plasminogen activator inhibitor‐1, mapped by mutagenesis and protection against an inactivating organochemical ligand
Authors: Jensen Jan K , Wind Troels , Andreasen Peter A
Published: October 2002

A distinguishing feature of serpins is their ability to undergo a conformational change consisting in insertion of the reactive centre loop (RCL) into β‐sheet A. In the serpin plasminogen activator inhibitor‐1 (PAI‐1), RCL movements are regulated by vitronectin, having a previously poorly defined binding site lateral to PAI‐1's β‐sheet A. Using a novel strategy, based on identification of amino acid residues necessary for vitronectin protection of PAI‐1 against inactivation by 4,4′‐dianilino‐1,1′‐bisnaphthyl‐5,5′‐disulfonic acid, we have defined a vitronectin binding surface spanning 10 residues between α‐helix F, β‐strand 2A, and α‐helix E. Our results contribute to elucidating the unique serpin conformational change.
Human substance P receptor undergoes agonist‐dependent phosphorylation by G protein‐coupled receptor kinase 5 in vitro
Authors: Warabi Kengo , Richardson Mark D. , Barry William T. , Yamaguchi Keisuke , Roush Eric D. , Nishimura Kinya , Kwatra Madan M.
Published: October 2002

G protein‐coupled receptor kinases (GRKs) phosphorylate agonist‐occupied G protein‐coupled receptors, leading to receptor desensitization. Seven GRKs, designated GRK1 through 7, have been characterized. GRK5 is negatively regulated by protein kinase C. We investigated whether human substance P receptor (hSPR) is a substrate of GRK5. We report that membrane‐bound hSPR is phosphorylated by purified GRK5, and that both the rate and extent of phosphorylation increase dramatically in the presence of substance P. The phosphorylation has a high stoichiometry (20±4 mol phosphate/mol hSPR) and a low K
m (1.7±0.1 nM). These data provide the first evidence that hSPR is a substrate of GRK5.
TUCAN/CARDINAL and DRAL participate in a common pathway for modulation of NF‐κB activation
Authors: Stilo Romania , Leonardi Antonio , Formisano Luigi , Di Jeso Bruno , Vito Pasquale , Liguoro Domenico
Published: October 2002

Proteins containing the caspase recruiting domain (CARD) have emerged as critical regulators of different signal transduction pathways, including those controlling apoptosis and activation of necrosis factor (NF)‐κB transcription factor. TUCAN/CARDINAL is a recently identified CARD‐containing protein involved in regulation of caspases and NF‐κB activation. We find that TUCAN/CARDINAL associates with DRAL, a p53‐responsive gene implicated in induction of apoptosis. We also show that, whereas TUCAN/CARDINAL exerts a suppressive effect on NF‐κB activity, expression of DRAL results in enhancement of NF‐κB activation. Thus, our observations suggest that DRAL and TUCAN/CARDINAL may participate in a regulatory mechanism that coordinates cellular responses controlled by NF‐κB transcription factor.
Heregulin promotes expression and subcellular redistribution of ADP‐ribosylation factor 3
Authors: Li Feng , Mandal Mahitosh , Mishra Sandip K , Barnes Christopher J , Kumar Rakesh
Published: October 2002

To identify genes whose expression is modulated by heregulin‐β1 (HRG), a regulatory polypeptide for mammary epithelial cells, we performed differential display screening of MCF‐7 cell mRNA. One cDNA clone upregulated by HRG was identical to human ADP‐ribosylation factor 3 (ARF3), a guanine nucleotide‐binding protein functioning in vesicular trafficking, phospholipase D activation and intracellular transport. HRG treatment increased expression of ARF3 mRNA and protein. Also, HRG triggered a rapid redistribution of ARF3, first to cell membranes and then to the nuclear compartment, where ARF3 colocalized with acetylated histone H3 in discrete regions. In addition, the ARF3 protein was developmentally regulated in the mammary gland with the highest levels in virgin and post‐weaning glands. Together, these findings suggest for the first time that stimulation of ARF3 expression, subcellular redistribution and interaction with acetylated histone H3 may play a role in the action of HRG in mammary epithelial cells.
The elastin peptides‐mediated induction of pro‐collagenase‐1 production by human fibroblasts involves activation of MEK/ERK pathway via PKA‐ and PI3K‐dependent signaling
Authors: Duca Laurent , Debelle Laurent , Debret Romain , Antonicelli Frank , Hornebeck William , Haye Bernard
Published: October 2002

Elastin peptides, such as κ‐elastin (kE), bind to the elastin receptor at the cell surface of human dermal fibroblasts and stimulate collagenase‐1 expression at the gene and protein levels. Using specific inhibitors and phosphospecific antibodies, we show here that the binding of elastin peptides to their receptor activates the extracellular signal‐regulated kinase (ERK) pathway; this activation is essential for the induction of pro‐collagenase‐1 production. Moreover, protein kinase A (PKA) and phosphatidylinositol 3‐kinase (PI3K) signaling were found to participate in ERK activation. Concomitantly, we demonstrate that stimulation by elastin peptides leads to enhanced DNA binding of activator protein‐1 (AP‐1). Our data indicate that the up‐regulation of collagenase‐1 following treatment of fibroblasts with elastin peptides results from a cross‐talk between PKA, PI3K and the ERK signaling pathways and that this regulation is accompanied by activation of AP‐1 transcription factors.
CB1 cannabinoid receptor‐mediated tyrosine phosphorylation of focal adhesion kinase‐related non‐kinase
Authors: Zhou Dan , Song Z.H
Published: October 2002

The effect of cannabinoid on the tyrosine phosphorylation of focal adhesion kinase (FAK) and focal adhesion kinase‐related non‐kinase (FRNK) was investigated in differentiated mouse neuroblastoma N1E‐115 cells. HU‐210, a potent cannabinoid agonist, elicited a time‐dependent enhancement of tyrosine phosphorylation of FRNK, but not FAK. Pretreatment of cells with antisense oligodeoxynucleotide targeting CB1 cannabinoid receptor abolished HU‐210‐induced FRNK tyrosine phosphorylation. In addition, pretreatment of cells with 8‐Br‐cAMP also blocked HU‐210‐induced FRNK tyrosine phosphorylation. These data demonstrated that HU‐210 induces FRNK tyrosine phosphorylation by activating Gi‐coupled CB1 cannabinoid receptor in N1E‐115 cells. This newly discovered, cannabinoid‐induced FRNK tyrosine phosphorylation might be a novel mechanism for cannabinoid‐induced functional changes.
Intrapartum cardiotocography and fetal pulse oximetry in assessing fetal hypoxia
Authors: Leszczynska‐Gorzelak B , Poniedzialek‐Czajkowska E , Oleszczuk J
Published: October 2002

Objectives: A retrospective analysis of short‐term variability (STV), a cardiotocography (CTG) parameter, in relation to fetal blood saturation values (FSpO2) obtained by fetal pulse oximetry. Methods: The study included 26 healthy pregnant women monitored continuously during delivery with both cardiotocography and fetal pulse oximetry. Results: Lower FSpO2 values were observed in the group showing STV levels ≤6.0 ms in the 1st stage of labor (44.7±3.46% vs. 49.2±1.8%), but this result was not statistically significant. In the 2nd stage of labor, FSpO2 values in the group with STV levels ≤6.0 ms were significantly lower than those with STV levels >6.0 ms (34.4±2.9% vs. 43±7.2%; P<0.001). A positive correlation was found between STV levels ≤6.0 ms and mean FSpO2 values in the 2nd stage of labor. Conclusions: 1. A significant relationship was observed between short‐term variability in the cardiotocographic records and fetal blood saturation levels in the 2nd stage of labor. 2. Fetal pulse oximetry can be valuable in assessing fetal wellbeing, especially when CTG records are abnormal.
Outcome of pregnancy with severe liver disease
Authors: Tank P.D. , Nadanwar Y.S. , Mayadeo N.M.
Published: October 2002

Objectives: To study the incidence, presentation, and outcome of patients with severe liver disease in an urban Indian population. Method: 26 patients with severe liver disease were identified in the study period of one year at a teaching tertiary care institute in Mumbai. Investigations included bedside Bleeding and Clotting Time (BT/CT), coagulation profiles and liver and renal function tests. Management was directed towards initial stabilization followed by early delivery in an intensive care setting. Result: 80.71% of the patients had HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) syndrome. The remaining were cases of acute fulminant hepatitis and acute fatty liver of pregnancy. The most consistent finding was thrombocytopenia (88.46%). Disseminated Intravascular Coagulopathy (DIC) was the most common complication (65%). BT/CT were 100% sensitive for the diagnosis of DIC. Maternal and perinatal mortality were 42.3% and 61.5% respectively. Conclusion: Intensive care facilities and an early diagnosis are essential for the management of mothers with severe liver disease. Prognosis is poor for patients with fulminant hepatitis and acute fatty liver. Screening for DIC is a must. Delay in recovery of biochemical parameters may indicate atypical disease. Patient education is essential at discharge.
Growth of the fetal lens and orbit
Authors: Dilmen G , Köktener A , Turhan N.Ö , Tez S
Published: October 2002

Objectives: To present normal lens and orbital measurement ranges by gestational age. Methods: Three hundred and thirty‐five women with uneventful pregnancies were evaluated from the 15th to the 40th week of gestation. Lens and orbital measurements were added to routine biometric measurements for normal fetuses. Results: A strong linear correlation was observed between gestational age (GA) and lens diameter (R2=0.89; P<0.0001), circumference (R2=0.89; P<0.0001), and surface (R2=0.90; P<0.0001). A linear correlation was also found between GA and orbital diameter (R2=0.92; P<0.0001), circumference (R2=0.92; P<0.0001) and surface (R2=0.95; P<0.0001). A linear growth function was observed between biparietal diameter and both lens diameter (R2=0.90; P<0.0001) and orbital diameter (R2=0.94; P<0.0001). Conclusions: Lens and orbital measurements provide normative data for fetal growth and development. These data may be also helpful in detecting fetal ocular anomalies.
Integrated product development practices and competitive capabilities: the effects of uncertainty, equivocality, and platform strategy
Authors: Koufteros Xenophon A. , Vonderembse Mark A. , Doll William J.
Published: October 2002

Product development occurs more frequently as product life cycles shrink and new product offerings expand. In this high‐change and complex environment, firms face high levels of uncertainty and equivocality, and in response, they seek integrative structural mechanisms. In these organizations, product development is characterized by the use of heavyweight product development managers, concurrent engineering, and computer usage. These mechanisms give product development efforts the senior leadership to overcome resistance, the ability to integrate and coordinate activities, the access to relevant information, and the ability to process it effectively. This research describes a framework for product development practices, and it discusses relations among these variables as well as important performance variables (product innovation, quality, premium pricing, and profitability). Based on responses from 244 manufacturing firms, the study suggests that heavyweight product development managers drive the application of concurrent engineering and computer use. Computer use has a significant and positive impact on product innovation, and concurrent engineering has a positive effect on quality. Product innovation also seems to have an influence on quality. Both quality and product innovation have a significant and positive impact on premium pricing, which, in turn, influences profitability. The extent to which a firm uses a product platform strategy seems to be an important contextual variable that affects the nature of the relationships among product development practices and competitive capabilities. Firms operating in uncertain or equivocal environments appear to adopt higher levels of integrated product development practices than firms operating in low uncertainty or low equivocality environments.
Low frequency EMF regulates chondrocyte differentiation and expression of matrix proteins
Authors: McK. Ciombor Deborah , Lester Gayle , Aaron Roy K. , Neame Peter , Caterson Bruce
Published: October 2002

This study describes the enhancement of chondrogenic differentiation in endochondral ossification by extremely low frequency pulsed electric/magnetic fields (EMFs). The demineralized bone matrix (DBM)‐induced endochondral ossification model was used to examine the effects of EMF stimulation. [35S]‐Sulfate and [3H]‐thymidine incorporation and glycosaminoglycan (GAG) content were determined by standard methods. Proteoglycan (PG) and GAG molecular size and composition were determined by gel chromatography and sequential enzyme digestion. Immunohistochemical and Western blot analysis of PGs were done with antibodies 2B6, 3B3, 2D3 and 5D4. Northern analysis of total RNA extracts was performed for aggrecan, and type II collagen. All data was compared for significance by Student's t‐ or analysis of variance (ANOVA)‐tests.

The EMF field accelerated chondrogenesis as evidenced by an increase in: (1) 35SO4 incorporation and GAG content, (2) the number of chondrocytes at day 8 of development, (3) the volumetric density of cartilage and (4) the extent of immunostaining for 3B3 and 5D4. No differences in DNA content or [3H]‐thymidine incorporation were observed between control and stimulated ossicles, suggesting the absence of enhanced cell proliferation or recruitment as a mechanism for the acceleration. PG and GAG molecular sizes and GAG chemical composition were similar in stimulated and control ossicles, indicating that stimulation resulted in an accelerated synthesis of normal cartilage molecules. The increased expression of PG and type II collagen mRNA as well as a greater immunoreactivity of 3B3 and 504 suggest an increase in the rate of differentiation of chondrocytes and enhanced phenotypic maturation.© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Biomechanical regulation of type I collagen gene expression in ACLs in organ culture
Authors: Hsieh Adam H. , Sah Robert L. , Sung K.‐L. Paul
Published: October 2002

In this study, an ex vivo organ culture system that allows the application of controlled loads to the anterior cruciate ligament (ACL) was designed and used to characterize the influence of a step input in mechanical load on gene expression. A procedure for isolating bone–ACL–bone (B–ACL–B) complexes from rat knees was developed. After harvest and 24 hour culture, B–ACL–B complexes exhibited percentages of viability similar to that in intact ACLs (∼90%). Application of a physiologically relevant load of 5 N (superimposed on a 1 N tare load) resulted in changes in levels of mRNA encoding type I collagen. While levels of type I collagen mRNA significantly increased 32 ± 13% (mean ± standard errors of the mean (SEM)) over controls within the first hour of loading, levels decreased significantly to 44 ± 9% of control after 2 h. Displacements induced by the 5 N load were measured by video dimensional analysis. Calculated axial strains of 0.141 ± 0.034 were achieved rapidly during the first hour and remained essentially unchanged thereafter. These results demonstrate the feasibility of maintaining ligaments in organ culture and illustrate the time course expression of type I collagen following the application of a mechanical load. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
The effects of graft width and graft laxity on the outcome of caprine anterior cruciate ligament reconstruction
Authors: Cummings J. F. , Grood E. S. , Levy M. S. , Korvick D. L. , Wyatt R. , Noyes F. R.
Published: October 2002

We studied how initial graft size and initial graft laxity affected the biomechanics of anterior cruciate ligament (ACL) reconstruction at six months. Sixteen goats had bilateral reconstructions staged eight weeks apart. Autografts 4 and 7 mm wide were taken from the central patellar tendon (PT). Lax grafts were created by adding 4 mm slack to the graft before fixing. We reconstructed each joint using a combination of width and laxity treatments. Both factors were changed for the contralateral joint and all combinations appeared with equal frequency. At six months we measured the joint extension limit, anterior–posterior (AP) translation, and osteoarthritic changes. The grafts were then tested to failure to determine their mechanical properties. After six months the difference in initial treatments had disappeared: there was no difference in graft cross‐section due to the different initial widths and there was no difference in joint AP translation due to the initial graft laxity. We did observe that wide grafts were associated with a block to extension, decreased joint AP translation, and increased articular cartilage damage and osteophyte formation. While AP translation was reduced, it was correlated with decreased extension, possibly indicating an increase in scar tissue formation rather than a more functional graft. Neither graft width nor graft laxity produced differences in any graft mechanical properties. This suggests that the use of larger grafts to prevent increased AP translation has undesirable complications. Ultimately, we conclude that neither of these surgical treatments strongly affects the biomechanical result of caprine ACL reconstruction. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Muscle reflexes during gait elicited by electrical stimulation of the posterior cruciate ligament in humans
Authors: Fischer‐Rasmussen T. , Krogsgaard M. R. , Jensen D. B. , Dyhre‐Poulsen P.
Published: October 2002

We investigated the influence of electrical stimulation of the posterior cruciate ligament (PCL) on the motoneuron pool of the thigh and calf muscle during gait. The study group comprised eight young men without any history of injury to the knee joints. Multistranded teflon‐insulated stainless steel wires were inserted into the PCL guided by sonography and in four subjects also into the fat pad of the knee. The PCL was electrically stimulated during gait on a treadmill at heel strike and 100 ms after heel strike. Electromyographic signals were recorded with bipolar surface electrodes placed over the vastus medialis, rectus femoris, vastus lateralis, biceps femoris caput longum, and semitendinosus muscles. The stimuli consisted of four pulses delivered at 200 Hz; the stimulus amplitude was two to three times the sensory threshold. The electrical stimulation of the PCL inhibited the ongoing muscle activity in both the quadriceps and the hamstrings. The latency of the inhibition ranged between 78 and 148 ms in the quadriceps, between 88 and 110 ms in the hamstrings and between 189 and 258 ms in m. gastrocnemius. Stimulation of the fat pad of the knee did not influence the thigh and calf muscle motoneuron pool as evidenced by electromyography. The response elicited from the stimulation of the PCL was not limited to a specific muscle group but depended on ongoing muscle contraction, which suggests that the mechanoreceptors in the PCL are involved in the control of all muscles acting on the knee joint during gait. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Perception of vertical and horizontal orientation in children with scoliosis
Authors: Cheung John , Sluiter Wim J. , Veldhuizen Albert G. , Cool Jan C. , Van Horn Jim R.
Published: October 2002

To determine whether the perception of body posture is altered in idiopathic scoliosis, a simple neurophysiologic experiment through laser line projection was conducted to test this hypothesis in three groups of individuals: 89 children with idiopathic scoliosis (IS), 50 children with congenital scoliosis (CS) and 45 controls without scoliosis. The subjects were instructed to adjust a laser line projection to the direction of gravity in vertical and in horizontal projections in a dark environment. The performance, expressed as the deviation from the earth vertical (measured in degrees), was calculated by a computer. The three groups fulfilled the vertical and horizontal adjustments within the same accuracy. No relation with age, sex or severity of scoliotic deformity was found. Yet, the angle between vertical and horizontal laser lines was significantly related with the severity of scoliosis, both in IS and CS. In contrast to our hypothesis, it was concluded that perception of postural control in IS is not altered. Therefore, this study indicates that IS is not likely to be caused by a dysfunction of postural control. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Tenascin‐C expression and distribution in cultured human chondrocytes and chondrosarcoma cells
Authors: Ghert Michelle A. , Qi Wen‐Ning , Erickson Harold P. , Block Joel A. , Scully Sean P.
Published: October 2002

Tenascin‐C (TNC) is an oligomeric glycoprotein of the extracellular matrix with several distinct isoforms variably expressed during embryogenesis, tumorogenesis, angiogenesis and wound healing. In the normal human adult, TNC is found in large concentrations in articular cartilage, suggesting tissue‐specific function. The purpose of this study was to determine the specific in vitro TNC splicing patterns of articular chondrocytes and a human chondrosarcoma cell line. Cells were cultured in a three‐dimensional bead system and TNC splice variant expression and distribution were examined with the use of Western blotting techniques, semi‐quantitative reverse‐transcription polymerase chain reaction and immunohistochemistry. At both the transcriptional and post‐translational levels, the chondrocytes were found to express significantly higher levels of the smaller 220 kDa isoform (P < 0.01), which was predominantly incorporated into the matrix. The splicing pattern of the malignant cells was characterized by a higher proportion of the larger 320 kDa isoform which was extruded into the media. In vivo studies are necessary to verify the expression of the large TNC isoform in chondrosarcoma and the production and integration of the smaller isoform in normal chondroid matrix. In addition, elucidation of the biologic functions of the two major TNC isoforms may lead to the development of novel diagnostic and therapeutic approaches to chondrosarcoma. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Sciatic conditioned medium increases survival, proliferation and differentiation of retinal cells in culture
Authors: Torres Patrı́cia Maria Mendonça , Guilarducci Carla Valéria Vieira , Franco Alfred Sholl , de Araujo Elizabeth Giestal
Published: October 2002

Many evidences clearly demonstrate that Schwann cells provide trophic support for neurons. Different cytokines, including neurotrophins (NTs), are produced and released by Schwann cells. These trophic molecules play an important role on neuronal survival either during the development or during adult life. Cytokines have also a pivotal role on neuronal regeneration after lesions occurring during pathological conditions. The aim of this work was to study the effect of sciatic conditioned medium (SCM) on rat retinal cells maintained in culture. Our results show that treatment with SCM obtained after 14 days in vitro (SCM 14 day) induced a three‐fold increase in protein content of the culture after 48 h in vitro and this value remained equally high up to 72 h. This effect was totally blocked either by addition of 30 μM BAPTA‐AM, an intracellular calcium chelator, 15 μM fluorodeoxyuridine, an inhibitor of cell division, or 10 μM genistein (geni) plus 1.25 μM chelerythrine chloride (CC), the two last ones inhibitors of tyrosine kinases and protein kinase C, respectively. SCM induced an increase in [3H]‐choline uptake and [3H]‐thymidine incorporation of retinal cells. SCM also stimulated an increase in cytoplasmic processes outgrowth of retinal cells and survival of retinal ganglion cells. Our results clearly suggest that soluble molecules released by sciatic nerve fragments are able to increase the proliferation and survival of retinal cells in culture.
The programmatic turnaround of communist successor parties in East Central Europe, 1989–1998
Authors: Grzymala-Busse Anna
Published: October 2002

The communist parties’ adaptation to democracy is one of the more remarkable developments of post-1989 politics in East Central Europe. Ironically, unresponsive and incompetent ruling communist parties have in some cases spawned successors that have been able to respond to democratic electoral cleavages and convince large portions of the electorate of their ability to govern democratically and competently. This paper argues that the main factor underlying this ability has been organizational transformation of the communist parties: specifically, the extent to which these parties centralized and streamlined their organizations, while breaking with a discrediting past. This transformation is itself a function of elite skills developed under communism.
Transformation theory: scientific or political?
Authors: Pickel A.
Published: October 2002

This essay argues that the search for a scientific theory of transformation is ill-conceived. Postcommunist transformation is not a scientific project but a political project. It therefore requires a political theory rather than a scientific theory of transformation. The distinction is important because social scientists as political actors have played a siginificant role in the transformation process. Several examples are provided to illustrate the relationship between social science and transformation. In political theories of transformation, social science knowledge is subordinated and instrumental. This does not reduce the significance of social science, but rather reconceptualizes it. The legitimate functions of social science in transformation theory have critical, constructive and applied dimensions.
Prognostic implication of myocardial texture analysis in idiopathic dilated cardiomyopathy
Authors: Dağdeviren Bahadir , Akdemir Osman , Eren Mehmet , Bolca Osman , Oğuz Enis , Gürlertop Yekta , Tezel Tuna
Published: October 2002

Background and aim:

Abnormal myocardial acoustic properties have been reported in patients with idiopathic dilated cardiomyopathy (IDC). The aim of this study was to investigate the relationship between quantitative ultrasonic textural alterations of myocardium and clinical outcome in IDC.

Methods:

Baseline clinical and echocardiographic variables were obtained from 28 patients with IDC. By using a videodensitometric approach, quantitative myocardial texture analysis was performed on images obtained from septum and posterior wall (PW). Cyclic variation (CV) index of mean gray level (MGL) was calculated according to the formula: (MGLdiast−MGLsyst)/MGLdiast×100. All patients were followed for an average of 11±5 months for the occurrence of cardiac death or repeated hospitalization due to worsening of heart failure.

Results:

During follow‐up, 10 patients experienced cardiac events (6 cardiac deaths and 4 heart failure events). The CV indexes of both septum and PW were significantly lower in patients with cardiac events than those of event free patients (6.8±9.6% vs. 13.6±8.2%, P<0.05 and 5.3±6.4% vs.15.7±7.2% P<0.001, respectively). Univariate analysis defined the following variables as predictors of outcome: PW–CV index (χ2‐13.0, P‐0.0003), transmitral E/A ratio (χ2‐12.5, P‐0.0004), symptom status (χ2‐8.7, P‐0.003), and septum‐CV index (χ2‐4.7, P‐0.03). Multivariate stepwise regression analysis showed that the PW–CV index (χ2‐7.5, P‐0.006) and E/A ratio (χ2‐6.5, P‐0.01) were the independent predictors of outcome. The event‐free survival rate of patients with PW–CV index <11% was significantly lower than those with an index ≥11 (35.7% vs. 92.8%, P‐0,001).

Conclusion:

The assessment of severely depressed CV index provides valuable prognostic information in patients with IDC.
The Heart Failure Journal Club: a review of publications on Heart Failure in the European Heart Journal
Authors: Louis Amala A.
Published: October 2002

This is one of a series of articles reviewing the literature on heart failure from the world's leading cardiovascular journals. All articles published in the European Heart Journal during the year 2000 were identified and those relevant to heart failure were reviewed. This includes all original scientific articles, systematic reviews and key editorials. This may prove a valuable resource for keeping up to date with the literature on heart failure.
Effect of thalidomide on the skeletal muscle in experimental heart failure
Authors: Vescovo Giorgio , Ravara Barbara , Angelini Annalisa , Sandri Marco , Carraro Ugo , Ceconi Claudio , Libera Luciano Dalla
Published: October 2002

Background

Tumour Necrosis Factor α (TNFα) has been shown to contribute to heart failure (CHF) progression.

Aims

We have tried to antagonise the detrimental effects of TNFα on skeletal muscle apoptosis, by using thalidomide, a drug that inhibits its biosynthesis.

Methods

CHF was induced in 20 rats by injecting monocrotaline, which determines right ventricle (RV) failure. After 2 weeks, when CHF developed, 12 rats were treated with thalidomide 3.5.mg/kg per day for 2 weeks. Eight had saline and served as CHF controls.

Results

Thalidomide failed to decrease TNFα and its second messenger sphingosine (SPH), but was able to prevent the shift toward the fast myosin heavy chains. In the Tibialis Anterior muscle of the thalidomide group, the degree of atrophy, the number of apoptotic nuclei and the levels of caspases, were similar to those of the CHF controls.

Conclusions

Thalidomide, at the doses used in this study, which are the same employed for the treatment of tubercolosis, leprosy, AIDS and cancer in humans, did not lower either TNFα or SPH and only marginally influenced the apoptosis‐induced muscle atrophy. Since other TNFα blockers are under investigation for improving the clinical status of patients with CHF, the present data could be relevant in the design of randomised clinical trials in humans.
Rationale and design of the carvedilol or metoprolol European trial in patients with chronic heart failure: COMET
Authors: Poole‐Wilson Philip A. , Cleland John G.F. , Di Lenarda Andrea , Hanrath Peter , Komajda Michel , Metra Marco , Remme Willem J. , Swedberg Karl , Torp‐Pedersen Christian
Published: October 2002

In large clinical trials both carvedilol and metoprolol have been shown to reduce mortality and morbidity in patients with chronic heart failure. Carvedilol is an adrenoceptor antagonist, which inhibits beta1‐, beta2‐, and alpha1‐adrenergic receptors. Carvedilol has additional metabolic and antioxidant properties. Metoprolol is a selective antagonist of beta1‐adrenergic receptors. The carvedilol or metoprolol European trial (COMET) is the first study to investigate whether beta‐blocking agents with differing pharmacological profiles exert different effects on morbidity and mortality in patients with chronic heart failure. 3029 patients from 15 different European countries were enrolled into COMET and will be followed until 1020 fatal events have been observed, unless the data and safety monitoring committee (DSMC) recommends early termination. The target dose for carvedilol is 25 mg bid and for metoprolol tartrate 50 mg bid. This manuscript outlines the rationale, design and possible outcomes of COMET.
The effect of carvedilol in patients with impaired left ventricular systolic function following an acute myocardial infarction
Authors: Otterstad Jan Erik , Ford Ian
Published: October 2002

In previous beta‐blocker trials, post‐myocardial infarction (MI) patients were essentially treated with a beta‐blocker or placebo. In the CAPRICORN trial, patients were selected on the basis of a left ventricular (LV) ejection fraction (EF) <40% following the index MI and randomised to carvedilol or placebo, in addition to modern secondary prophylaxis with ACE inhibitors, aspirin and statins. In 1959 patients with a mean LVEF of 33%, treatment with carvedilol over a mean follow‐up period of 15 months reduced total mortality from 15.3% with placebo to 11.9% with carvedilol [relative risk reduction (RRR) ‐23%, absolute risk reduction (ARR) ‐3.4%]. The incidence of recurrent MI was reduced from 5.8 to 2.3% (RRR 41%, ARR 2.3%). The number needed to treat (NNT) to prevent one death was 28 for the entire study period and 43 for 1 year of treatment. The results of the CAPRICORN trial are compared with three previous beta‐blocker post‐MI trials: the Gothenburg metoprolol trial (GMT), the Norwegian timolol trial (NTT) and the beta‐blocker heart attack trial (BHAT). The RRRs for total mortality were 36% in the GMT and NTT, and 27% in BHAT. The respective NNTs for total mortality were 32, 18 and 38. NNT for 1 year of treatment was 25 in NTT and 80 in BHAT. The RRR for recurrent MIs were 28% in NTT and 16% in BHAT. The reduction of mortality and recurrent MIs in CAPRICORN is within the range of previous post‐MI beta‐blocker studies. In post‐MI patients with LVEF<40%, add‐on treatment with a beta‐blocker should be given >48 h after initiation with an angiotensin‐converting enzyme inhibitor (ACEI) and then with a slow dose escalation as applied in CAPRICORN.