bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of Matrix Metalloproteinases Precedes Left Ventricular Remodeling in Hypertensive Heart Failure Rats
Authors: Sakata Yasushi , Yamamoto Kazuhiro , Mano Toshiaki , Nishikawa Nagahiro , Yoshida Junichi , Hori Masatsugu , Miwa Takeshi , Masuyama Tohru
Published: March 2004

Background—

Matrix metalloproteinases (MMPs) are activated in dilated failing hearts, and angiotensin-converting enzyme (ACE) inhibition prevents left ventricular (LV) dilatation. However, it remains unclear whether activation of MMPs precedes or is secondary to LV remodeling, and an effect of ACE inhibition on MMPs is unknown.

Methods and Results—

Dahl salt-sensitive rats fed a high-salt diet from 8 weeks served as the hypertensive heart failure (HF) model. LV echo, histological study, measurement of mRNA levels, and gelatin zymography were performed before (at 23 weeks) and after (at 26 weeks) the development of LV dilatation and pulmonary edema. The same procedures were conducted in the HF model rats treated with a subdepressor dose of ACE inhibitor (enalapril 5 mg · kg
−1
· d
−1
) from 9 weeks. Rats fed on normal chow served as age-matched controls. In the untreated HF model rats, gene expression of MMP-2 and MMP-9 and tissue gelatinase activity were elevated at 23 weeks without LV dilatation. LV dilatation, LV systolic dysfunction, and pulmonary edema occurred at 26 weeks, with further enhancement of the expression and activity of MMPs. ACE inhibition prevented such geometrical and functional deterioration. The gene expression and activity of MMPs were suppressed by ACE inhibition at 23 weeks without a decrease in blood pressure, and the suppressive effects continued at 26 weeks.

Conclusions—

MMPs are likely to trigger and promote LV remodeling, and ACE inhibition directly exerts inhibitory effect on MMPs, leading to the prevention of LV remodeling and dysfunction.
Antioxidant Intervention Attenuates Myocardial Neovascularization in Hypercholesterolemia
Authors: Zhu Xiang-Yang , Rodriguez-Porcel Martin , Bentley Michael D. , Chade Alejandro R. , Sica Vincenzo , Napoli Claudio , Caplice Noel , Ritman Erik L. , Lerman Amir , Lerman Lilach O.
Published: March 2004

Background—

Hypercholesterolemia (HC) and atherosclerosis can elicit oxidative stress, coronary endothelial dysfunction, and myocardial ischemia, which may induce growth-factor expression and lead to myocardial neovascularization. We tested the hypothesis that chronic antioxidant intervention in HC would attenuate neovascularization and preserve the expression of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF).

Methods and Results—

Three groups of pigs (n=6 each) were studied after 12 weeks of normal or 2% HC diet or HC+antioxidant supplementation (100 IU/kg vitamin E and 1 g vitamin C daily). Myocardial samples were scanned ex vivo with a novel 3D micro-CT scanner, and the spatial density and tortuosity of myocardial microvessels were determined in situ. VEGF mRNA, protein levels of VEGF and VEGF receptor-1, HIF-1α, nitrotyrosine, and superoxide dismutase (SOD) were determined in myocardial tissue. The HC and HC+antioxidant groups had similar increases in serum cholesterol levels. HC animals showed an increase in subendocardial spatial density of microvessels compared with normal (160.5±11.8 versus 95.3±8.2 vessels/cm
2
,
P
<0.05), which was normalized in HC+antioxidant (92.5±20.5 vessels/cm
2
,
P
<0.05 versus HC), as was arteriolar tortuosity. In addition, HC induced upregulation of VEGF, HIF-1α, and nitrotyrosine expression and decreased SOD expression and activity, all of which were preserved by antioxidant intervention.

Conclusions—

Changes in myocardial microvascular architecture invoked by HC are accompanied by increases in HIF-1α and VEGF expression and attenuated by antioxidant intervention. This underscores a role of increased oxidative stress in modulating myocardial microvascular architecture in early atherogenesis.
Value of Programmed Ventricular Stimulation After Tetralogy of Fallot Repair
Authors: Khairy Paul , Landzberg Michael J. , Gatzoulis Michael A. , Lucron Hugues , Lambert Jean , Marçon François , Alexander Mark E. , Walsh Edward P.
Published: March 2004

Background—

Studies have consistently shown that ventricular tachycardia (VT) and sudden cardiac death (SCD) complicate the long-term outcome after tetralogy of Fallot repair, yet the diagnostic and predictive value of electrophysiological testing in this population is uncertain.

Methods and Results—

A multicenter cohort of 252 patients with repaired tetralogy of Fallot undergoing programmed ventricular stimulation was followed up for 18.5±9.6 and 6.5±4.5 years after corrective surgery and electrophysiological testing, respectively. Clinical VT and/or SCD occurred in 24.6%. Sustained monomorphic VT and polymorphic VT were induced in 30.2% and 4.4%. Including polymorphic VT in the definition of inducibility improved sensitivity (66.1±6.0% versus 77.4±5.3%,
P
=0.0082) with a marginal reduction in specificity (81.6±2.8% versus 79.5±2.9%,
P
=0.0455). Positive and negative predictive values were 55.2±5.3% and 91.5±2.2%. Independent risk factors for inducibility were age at study ≥18 years (OR, 3.3), palpitations (OR, 2.8), prior palliative surgery (OR, 3.1), modified Lown criteria ≥2 (OR, 5.6), and cardiothoracic ratio ≥0.6 (OR, 3.3). Event-free survival rates in noninducible and inducible patients at 1, 5, 10, and 15 years were 97.9%, 92.8%, 89.3%, and 89.3% versus 79.4%, 62.6%, 58.7%, and 50.3%, respectively (
P
<0.0001). Both inducible monomorphic VT [relative risk (RR), 5.0;
P
=0.0002] and polymorphic VT (RR, 12.9;
P
<0.0001) predicted future clinical VT and SCD. In a multivariate analysis, inducible sustained VT was an independent risk factor for subsequent events (RR, 4.7; 95% CI, 1.2 to 18.5;
P
=0.0268).

Conclusions—

Programmed ventricular stimulation is of diagnostic and prognostic value in risk stratifying patients with repaired tetralogy of Fallot. In this patient population, inducible sustained polymorphic VT should not be disregarded as nonspecific.
Increased O
2
·−
Production and Upregulation of ET
B
Receptors by Sympathetic Neurons in DOCA-Salt Hypertensive Rats
Authors: Dai Xiaoling , Galligan James J. , Watts Stephanie W. , Fink Gregory D. , Kreulen David L.
Published: March 2004

Superoxide anion (O
2
·−
) production is elevated in the vasculature of hypertensive animals but it is not known if O
2
·−
production is also elevated in the sympathetic nervous system. We measured O
2
·−
levels in prevertebral sympathetic ganglia of deoxycorticosterone acetate (DOCA)-salt hypertensive rats using the dihydroethidine (DHE) fluorescence method. O
2
·−
was elevated in ganglia from DOCA-salt rats compared with normotensive sham rats. Treatment of ganglia with endothelin (ET)-1 (3×10
−8
mol/L) resulted in a 200% increase in fluorescence intensity in neurons, which was attenuated by the ET
B
receptor antagonist BQ788 (10
−7
mol/L). ET-1 also increased the O
2
·−
induced fluorescence in dissociated sympathetic neurons and PC-12 cells via activation of ET
B
receptors, but not ET
A
receptors. To evaluate whether elevated ET-1 levels in the ganglia might contribute to the elevated O
2
·−
found in ganglia we measured the amount of ET-1 using an ELISA assay. ET-1 levels in sham rat celiac ganglia were 695.6±40.9 picogram per gram; they were not different than ET-1 levels in ganglia from DOCA-salt rats. We then compared ET
B
receptor levels in ganglia from sham and DOCA-salt animals. ET
B
receptor mRNA levels were 32% higher and ET
B
receptor protein levels were 20% higher in celiac ganglia from DOCA-salt rats than from sham rats separately. In conclusion, O
2
·−
is elevated in prevertebral sympathetic ganglia in DOCA-salt hypertension, and ET-1 is a potent stimulus for the elevation of O
2
·−
levels in sympathetic ganglia, an effect that may be mediated by the upregulation of ET
B
receptors.
Leukemia Inhibitory Factor Activates Cardiac L-Type Ca
2+
Channels via Phosphorylation of Serine 1829 in the Rabbit Ca
v
1.2 Subunit
Authors: Takahashi Eiichi , Fukuda Keiichi , Miyoshi Shunichiro , Murata Mitsushige , Kato Takahiro , Ita Makoto , Tanabe Tsutomu , Ogawa Satoshi
Published: March 2004

We have previously reported that leukemia inhibitory factor (LIF) gradually increased cardiac L-type Ca
2+
channel current (
I
CaL
), which peaked at 15 minutes in both adult and neonatal rat cardiomyocytes, and this increase was blocked by the mitogen-activated protein kinase kinase inhibitor PD98059. This study investigated the molecular basis of LIF-induced augmentation of
I
CaL
in rodent cardiomyocytes. LIF induced phosphorylation of a serine residue in the α
1c
subunit (Ca
v
1.2) of L-type Ca
2+
channels in cultured rat cardiomyocytes, and this phosphorylation was inhibited by PD98059. When constructs encoding either a wild-type or a carboxyl-terminal–truncated rabbit Ca
v
1.2 subunit were transfected into HEK293 cells, LIF induced phosphorylation of the resultant wild-type protein but not the mutant protein. Cotransfection of constitutively active mitogen-activated protein kinase kinase also resulted in phosphorylation of the Ca
v
1.2 subunit in the absence of LIF stimulation. In in-gel kinase assays, extracellular signal–regulated kinase phosphorylated a glutathione
S
-transferase fusion protein of the carboxyl-terminal region of Ca
v
1.2 (residues 1700 through 1923), which contains the consensus sequence Pro-Leu-Ser-Pro. A point mutation within this consensus sequence, which results in a substitution of alanine for serine at residue 1829 (S1829A), was sufficient to abolish the LIF-induced phosphorylation. LIF increased
I
CaL
in HEK cells transfected with wild-type Ca
v
1.2 but not with the mutated version. These results provide direct evidence that LIF phosphorylates the serine residue at position 1829 of the Ca
v
1.2 subunit via the actions of extracellular signal–regulated kinase and that this phosphorylation increases
I
CaL
in cardiomyocytes.
Human Amyloidogenic Light Chains Directly Impair Cardiomyocyte Function Through an Increase in Cellular Oxidant Stress
Authors: Brenner Daniel A. , Jain Mohit , Pimentel David R. , Wang Bo , Connors Lawreen H. , Skinner Martha , Apstein Carl S. , Liao Ronglih
Published: March 2004

Primary amyloidosis is a systemic disorder characterized by the clonal production and tissue deposition of immunoglobulin light chain (LC) proteins. Congestive heart failure remains the greatest cause of death in primary amyloidosis, due to the development of a rapidly progressive amyloid cardiomyopathy. Amyloid cardiomyopathy is largely unresponsive to current heart failure therapies, and is associated with a median survival of less than 6 months and a 5-year survival of less than 10%. The mechanisms underlying this disorder, however, remain unknown. In this report, we demonstrate that physiological levels of human amyloid LC proteins, isolated from patients with amyloid cardiomyopathy (cardiac-LC), specifically alter cellular redox state in isolated cardiomyocytes, marked by an increase in intracellular reactive oxygen species and upregulation of the redox-sensitive protein, heme oxygenase-1. In contrast, vehicle or control LC proteins isolated from patients without cardiac involvement did not alter cardiomyocyte redox status. Oxidant stress imposed by cardiac-LC proteins further resulted in direct impairment of cardiomyocyte contractility and relaxation, associated with alterations in intracellular calcium handling. Cardiomyocyte dysfunction induced by cardiac-LC proteins was independent of neurohormonal stimulants, vascular factors, or extracellular fibril deposition, and was prevented through treatment with a superoxide dismutase/catalase mimetic. This study suggests that cardiac dysfunction in amyloid cardiomyopathy is directly mediated by LC protein-induced cardiomyocyte oxidant stress and alterations in cellular redox status, independent of fibril deposition. Antioxidant therapies or treatment strategies aimed at eliminating circulating LC proteins may therefore be beneficial in the treatment of this fatal disease.
Immune evasion proteins of human cytomegalovirus do not prevent a diverse CD8+ cytotoxic T-cell response in natural infection
Authors: Manley Thomas J. , Luy Lisa , Jones Thomas , Boeckh Michael , Mutimer Helen , Riddell Stanley R.
Published: March 2004

Although cytomegalovirus (CMV) expresses proteins that interfere with antigen presentation by class I major histocompatibility complex (MHC) molecules, CD8+ cytotoxic T cells (CTLs) are indispensable for controlling infection and maintaining latency. Here, a cytokine flow cytometry assay that employs fibroblasts infected with a mutant strain of CMV (RV798), which is deleted of the 4 viral genes that are responsible for interfering with class I MHC presentation, was used to examine the frequency and specificity of the CD8+ CTLs to CMV in immunocompetent CMV-seropositive individuals. A large fraction of the CD8+ CTL response was found to be specific for viral antigens expressed during the immediate early and early phases of virus replication and presented by fibroblasts infected with RV798 but not wild-type CMV. These results demonstrate that the inhibition of class I antigen presentation observed in CMV-infected cells in vitro is not sufficient to prevent the induction of a broad repertoire of CD8+ CTLs after natural infection in vivo. Thus, reconstitution of T-cell immunity in immunodeficient patients by cell therapy or by vaccination may need to target multiple viral antigens to completely restore immunologic control of CMV.
Expression, localization, and regulation of NOS in human mast cell lines: effects on leukotriene production
Authors: Gilchrist Mark , McCauley Scott D. , Befus A. Dean
Published: March 2004

Nitric oxide (NO) is a potent radical produced by nitric oxide synthase (NOS) and has pleiotrophic activities in health and disease. As mast cells (MCs) play a central role in both homeostasis and pathology, we investigated NOS expression and NO production in human MC populations. Endothelial NOS (eNOS) was ubiquitously expressed in both human MC lines and skin-derived MCs, while neuronal NOS (nNOS) was variably expressed in the MC populations studied. The inducible (iNOS) isoform was not detected in human MCs. Both growth factor-independent (HMC-1) and -dependent (LAD 2) MC lines showed predominant nuclear eNOS protein localization, with weaker cytoplasmic expression. nNOS showed exclusive cytoplasmic localization in HMC-1. Activation with Ca2+ ionophore (A23187) or IgE-anti-IgE induced eNOS phosphorylation and translocation to the nucleus and nuclear and cytoplasmic NO formation. eNOS colocalizes with the leukotriene (LT)-initiating enzyme 5-lipoxygenase (5-LO) in the MC nucleus. The NO donor, S-nitrosoglutathione (SNOG), inhibited, whereas the NOS inhibitor, NG-nitro-l-arginine methyl ester (L-NAME), potentiated LT release in a dose-dependent manner. Thus, human MC lines produce NO in both cytoplasmic and nuclear compartments, and endogenously produced NO can regulate LT production by MCs. (Blood. 2004;104: 462-469)
Complete remission of TEL-PDGFRB–induced myeloproliferative disease in mice by receptor tyrosine kinase inhibitor SU11657
Authors: Cain Jennifer A. , Grisolano Jay L. , Laird A. Douglas , Tomasson Michael H.
Published: March 2004

The TEL-PDGFRB fusion oncogene is associated with chronic myelomonocytic leukemia (CMML) and results in the expression of a constitutively active tyrosine kinase. SU11657 is a multitargeted selective inhibitor of class III/V receptor tyrosine kinases, including the platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) receptors KIT and FLT3. SU11657 inhibited TEL/PDGFβR kinase activity at nanomolar concentrations and inhibited TELPDGFRB-mediated factor-independent growth in myeloblastic 32D cells. Daily oral administration of SU11657 at 40 mg/kg suppressed myeloproliferation and significantly prolonged survival in TELPDGFRB mice treated prior to disease development, as well as in those with large tumor burdens. Our findings suggest that SU11657 or similar agents may have therapeutic potential in humans with hematologic malignancies expressing PDGFR fusion oncogenes. (Blood. 2004;104:561-564)
Monoclonal antibody IAC-1 is specific for activated α2β1 and binds to amino acids 199 to 201 of the integrin α2 I-domain
Authors: Schoolmeester Anne , Vanhoorelbeke Karen , Katsutani Shinya , Depraetere Hilde , Feys Hendrik B. , Heemskerk Johan M. W. , Hoylaerts Marc F. , Deckmyn Hans
Published: March 2004

In this study we describe the first monoclonal antibody, integrin activated conformation-1 (IAC-1), to recognize the active form of the platelet-collagen receptor, the integrin α2β1. IAC-1 has the following properties: (1) IAC-1 fails to bind to resting platelets but readily interacts with platelets stimulated by the glycoprotein VI-specific agonist, convulxin, and by other agonists; (2) similar concentration response relationships for binding of IAC-1 and soluble collagen were observed in convulxin-stimulated platelets; (3) the epitope for IAC-1 is T199Y200K201, which is located at the opposite site of the metal ion-dependent adhesion site in a region not involved in the I-domain “shifts” that occur upon ligand binding; (4) IAC-1 strongly binds to recombinant α2 I-domain, therefore suggesting that the neo-epitope appears to be exposed by an “unmasking” of I-domain-covering regions upon activation; (5) IAC-1 binds to platelets during adhesion to collagen under shear conditions, demonstrating activation of α2β1; (6) as IAC-1 does not interfere with platelet-collagen binding, it defines a new class of antibodies that is distinct from those belonging to the “cation- and ligand-induced binding sites” (CLIBSs) and the “ligand mimetic” group. These characteristics make IAC-1 a very powerful tool to study α2β1 activation under dynamic and physiologically relevant conditions. (Blood. 2004;104:390-396)
The peripheral cannabinoid receptor Cb2, frequently expressed on AML blasts, either induces a neutrophilic differentiation block or confers abnormal migration properties in a ligand-dependent manner
Authors: Alberich Jordà Meritxell , Rayman Nazik , Tas Marjolein , Verbakel Sandra E. , Battista Natalia , van Lom Kirsten , Löwenberg Bob , Maccarrone Mauro , Delwel Ruud
Published: March 2004

Cb2, the gene encoding the peripheral cannabinoid receptor, is located in a common virus integration site and is overex-pressed in retrovirally induced murine myeloid leukemias. Here we show that this G protein-coupled receptor (GPCR) is also aberrantly expressed in a high percentage of human acute myeloid leukemias. We investigated the mechanism of transformation by Cb2 and demonstrate that aberrant expression of this receptor on hematopoietic precursor cells results in distinct effects depending on the ligand used. Cb2-expressing myeloid precursors migrate upon stimulation by the endocannabinoid 2-arachidonoylglycerol and are blocked in neutrophilic differentiation upon exposure to another ligand, CP55940. Both effects depend on the activation of Gαi proteins and require the mitogen-induced extracellular kinase/extracellular signal-regulated kinase (MEK/ERK) pathway. Down-regulation of cyclic adenosine monophosphate (cAMP) levels upon Gαi activation is important for migration induction but is irrelevant for the maturation arrest. Moreover, the highly conserved G protein-interacting DRY motif, present in the second intracellular loop of GPCRs, is critical for migration but unimportant for the differentiation block. This suggests that the Cb2-mediated differentiation block requires interaction of Gαi proteins with other currently unknown motifs. This indicates a unique mechanism by which a transforming GPCR, in a ligand-dependent manner, causes 2 distinct oncogenic effects: altered migration and block of neutrophilic development. (Blood. 2004;104:526-534)
Prognostication of survival using cardiac troponins and N-terminal pro-brain natriuretic peptide in patients with primary systemic amyloidosis undergoing peripheral blood stem cell transplantation
Authors: Dispenzieri Angela , Gertz Morie A. , Kyle Robert A. , Lacy Martha Q. , Burritt Mary F. , Therneau Terry M. , McConnell Joseph P. , Litzow Mark R. , Gastineau Dennis A. , Tefferi Ayalew , Inwards David J. , Micallef Ivana N. , Ansell Stephen M. , Porrata Luis F. , Elliott Michelle A. , Hogan William J. , Rajkumar S. Vincent , Fonseca Rafael , Greipp Philip R. , Witzig Thomas E. , Lust John A. , Zeldenrust Steven R. , Snow Denise S. , Hayman Susan R. , McGregor Christopher G. A. , Jaffe Allan S.
Published: March 2004

Primary systemic amyloidosis (AL) is a fatal plasma cell disorder. Pilot data suggest survival is better in patients undergoing peripheral blood stem cell transplantation (PBSCT), but the selection process makes the apparent benefit suspect. We have reported that circulating cardiac biomarkers are the best predictors of survival outside of the transplantation setting. We now test whether cardiac troponins (cTnT and cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are prognostic in transplant recipients. In 98 patients with AL undergoing PBSCT, serum cardiac biomarkers were measured (cTnT, 98 patients; cTnI, 65 patients; and NT-proBNP, 63 patients). Elevated levels of cTnT, cTnI, and NT-proBNP were present in 14%, 43%, and 48% of patients, respectively. At 20 months median follow-up, median survival has not been reached for patients with values below the thresholds; in patients with values above the thresholds, median survival is 26.1 months, 66.1 months, and 66.1 months, respectively. Our previously reported risk systems incorporating these markers were also prognostic, notably the cTnT/NT-proBNP staging. Using this system, 49%, 38%, and 13% of patients were in stage I, stage II, and stage III, respectively. Determining levels of circulating biomarkers may be the most powerful tool for staging patients with AL undergoing PBSCT.
TGF-β down-regulates IL-1α-induced TLR2 expression in murine hepatocytes
Authors: Matsumura Takayuki , Hayashi Hidetoshi , Takii Takemasa , Thorn Caroline F , Whitehead Alexander S , Inoue Jun-ichiro , Onozaki Kikuo
Published: March 2004

We have previously reported that the proinflammatory cytokine interleukin (IL)-1α can up-regulate functional Toll-like receptor 2 (TLR2) expression in primary-cultured murine hepatocytes, and bacterial lipopeptide (BLP) is capable of signaling through TLR2 to induce serum amyloid A (SAA) expression in hepatocytes. In the present study, we investigated the effect of the anti-inflammatory cytokine transforming growth factor-β (TGF-β) on TLR2 expression in primary-cultured murine hepatocytes. At the mRNA and protein levels, TGF-β up-regulated TLR2 expression but inhibited TLR2 expression induced by IL-1α at 24 h. BLP-induced SAA promoter activity could be augmented by pretreatment with IL-1α but not TGF-β or the combination of TGF-β and IL-1α. TLR2 promoter activity and nuclear factor (NF)-κB activation by IL-1α were inhibited by TGF-β treatment. Pretreatment with TGF-β strongly suppressed IL-1α-induced TLR2 promoter activity and NF-κB activation, which was consistent with the down-regulation of type I IL-1 receptor (IL-1RI) mRNA expression. IL-1α up-regulated IL-1RI mRNA, but it was inhibited by the treatment with TGF-β. These results suggest that TGF-β suppresses the induction of TLR2 expression by IL-1α through down-regulation of IL-1RI expression. These results also demonstrate the disparity between IL-1α and TGF-β in regulating TLR2-mediated SAA production in hepatocytes.
Ascorbate-mediated enhancement of reactive oxygen species generation from polymorphonuclear leukocytes: modulatory effect of nitric oxide
Authors: Sharma Prashant , Raghavan Santhanam A V , Saini Rashmi , Dikshit Madhu
Published: March 2004

Recent studies from our laboratory have demonstrated that ascorbate potentiated enzymatic synthesis of nitric oxide (NO) from polymorphonuclear leukocytes (PMNs). NO is known to modulate various function of PMNs such as chemotaxis, adherence, aggregation, and generation of reactive oxygen species (ROS). The role of ascorbate in the PMN phagocytosis, ROS generation, and apoptosis was thus evaluated in the present study. Ascorbate and its oxidized and cell-permeable analog, dehydroascorbate (DHA), did not affect the phagocytosis but enhanced ROS generation and apoptosis following treatment with Escherichia coli or arachidonic acid. A detailed investigation on the DHA-mediated response indicated that inhibitors of DHA uptake, reduced nicotinamide adenine dinucleotide phosphate oxidase, NO synthase, or ROS scavengers attenuated ROS generation. In DHA-treated cells, enhanced generation of peroxynitrite was also observed; thus, ascorbate-mediated ROS and reactive nitrogen species generation might mediate cytotoxicity toward the ingested microbes and subsequently, augmented PMN apoptosis. Results of the present study have helped in delineating the role of ascorbate in the modulation of NO-mediated ROS generation from PMNs.
Immunopathogenesis of atherosclerosis
Authors: Ludewig Burkhard , Krebs Philippe , Scandella Elke
Published: March 2004

Recent clinical studies indicate that the number of microbial infections (the “pathogen burden”) critically determines the development and progression of atherosclerotic disease. Viruses or bacteria with a specific tropism for cells of the vascular wall may contribute to the initial vascular injury via direct cytopathic effects or via the induction of genuine autoimmune responses. Immunopathological processes such as molecular mimicry, epitope spreading, or bystander activation of self-reactive lymphocytes most likely fuel the chronic inflammatory process in the vascular wall. Recognition of atherogenesis as a pathogen-driven, immunopathological process makes this disease amenable to new treatment strategies such as vaccination or immunomodulation.
Gene Expression Profiles and Molecular Markers To Predict Recurrence of Dukes' B Colon Cancer
Authors: Wang Yixin , Jatkoe Tim , Zhang Yi , Mutch Matthew G. , Talantov Dmitri , Jiang John , McLeod Howard L. , Atkins David
Published: March 2004

Purpose

The 5-year survival rate of patients with Dukes' B colon cancer is approximately 75%. Identification of the patients at high risk of recurrence in this group would allow better staging and more informed use of adjuvant chemotherapy. In this study, we used DNA chip technology to systematically identify new prognostic markers for tumor relapse in Dukes' B patients.

Patients and Methods

Using Affymetrix U133a GeneChip containing approximately 22,000 transcripts (Affymetrix, Santa Clara, CA), RNA samples from 74 patients with Dukes' B colon cancer were analyzed. Thirty-one patients developed tumor relapse in less than 3 years, whereas 43 patients remained disease-free for more than 3 years after surgery. Two supervised class prediction approaches were used to identify gene markers that can best discriminate between patients who would experience relapse and patients who would remain disease-free. A multivariate Cox model was built to predict recurrence.

Results

Gene expression profiling identified a 23-gene signature that predicts recurrence in Dukes'B patients. This signature was validated in 36 independent patients. The overall performance accuracy was 78%. Thirteen of 18 relapse patients and 15 of 18 disease-free patients were predicted correctly, giving an odds ratio of 13 (95% CI, 2.6 to 65; P = .003). The log-rank test indicated a significant difference in disease-free time between the predicted relapse and disease-free patients (P = .0001).

Conclusion

The clinical value of these markers is that the patients at a high predicted risk of relapse (13-fold risk) could be upstaged to receive adjuvant therapy, similar to Dukes' C patients. Our data highlight the feasibility of a prognostic assay that could focus more intensive treatment for localized colon cancer.
Further Evidence for the Role of Glucose as a Metabolic Regulator of Hypothalamic Gonadotropin-Releasing Hormone Pulse Generator Activity in Goats
Authors: Ohkura Satoshi , Ichimaru Toru , Itoh Fumiaki , Matsuyama Shuichi , Okamura Hiroaki
Published: March 2004

The present study examined the relative importance of blood glucose vs. free fatty acids as a metabolic signal regulating GnRH release as measured electrophysiologically by multiple-unit activity (MUA) in the arcuate nucleus/median eminence region in ovariectomized, estradiol-treated goats. MUA was recorded before, during, and after: 1) cellular glucoprivation by peripheral infusion of 2-deoxy-d-glucose (2DG; 25, 50, and 75 mg/kg·h, iv); 2) peripheral hypoglycemia in response to various doses (15–195 mU/kg·h, iv) of insulin infusion; and 3) cellular lipoprivation induced by peripheral infusion of sodium mercaptoacetate (MA; 2.4 mg/kg·h alone or combined with 25 mg/kg·h of 2DG, iv), and effects on the interval of characteristic increases in MUA (MUA volleys) were examined. Infusion of the highest dose of 2DG increased the mean interval between MUA volleys, whereas the lower doses of 2DG had no effect on volley interval. The MUA volley intervals lengthened as insulin-induced hypoglycemia became profound. There was a negative correlation between MUA volley intervals and blood glucose concentrations during insulin infusion, and coinfusion of glucose with insulin returned the MUA volley interval to a normal frequency. Infusion of MA alone or MA with 2DG did not increase MUA volley intervals. These findings demonstrate that glucose availability, but not fatty acids, regulates the GnRH pulse generator activity in the ruminant. Glucose is considered a key metabolic regulator that fine-tunes pulsatile GnRH release.
Down-Regulation of Adipose 11β-Hydroxysteroid Dehydrogenase Type 1 by High-Fat Feeding in Mice: A Potential Adaptive Mechanism Counteracting Metabolic Disease
Authors: Morton Nicholas M. , Ramage Lynne , Seckl Jonathan R.
Published: March 2004

The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD-1) amplifies intracellular glucocorticoid action in vivo. 11β-HSD-1 activity is increased in adipose tissues of obese humans and genetically obese rodents, providing a mechanistic basis for the similarities between metabolic disease arising from high circulating glucocorticoids (Cushing’s syndrome) and idiopathic obesity/metabolic syndrome where plasma glucocorticoids are typically unaltered. Fat-specific overexpression of 11β-HSD-1 produces a metabolic syndrome in mice, whereas 11β-HSD-1 null mice resist high-fat diet (HF)-induced visceral obesity and its metabolic consequences. Here we compared the effects of chronic (18 wk) HF feeding on adipose 11β-HSD-1 activity in strains of mice that are either resistant (A/J) or prone (C57BL/6J) to metabolic disease. 11β-HSD-1 activity was highest in sc fat, followed by epididymal fat, with lowest activity in the mesenteric visceral depot of both strains. 11β-HSD-1 activity was lower in white adipose tissues of A/J compared with C57BL/6J mice. Chronic HF feeding unexpectedly caused a down-regulation of 11β-HSD-1 in adipose tissues of both strains, despite comparable adiposity. However, A/J mice down-regulated adipose 11β-HSD-1 to a significantly lower level than C57BL/6J mice in white and thermogenic brown adipose tissues. We propose that a lower adipose 11β-HSD-1 set point affords a metabolic protection to A/J mice. Adaptive down-regulation of adipose 11β-HSD-1 in response to chronic HF represents a novel mechanism that may counteract metabolic disease.
Carnitine Palmitoyltransferase-1 (CPT-1) Activity Stimulation by Cerulenin via Sympathetic Nervous System Activation Overrides Cerulenin’s Peripheral Effect
Authors: Jin Yong-Jun , Li Song-Zhe , Zhao Zheng-Shan , An Juan Ji , Kim Ryang Yeo , Kim Yoo Mee , Baik Ja-Hyun , Lim Sung-Kil
Published: March 2004

To clarify the paradoxic effects of cerulenin, namely its in vitro inhibitory effects on fat catabolism and its in vivo reduction of fat mass, we studied the in vivo and in vitro effects of cerulenin on carnitine palmitoyltransferase-1 (CPT-1) activity, the rate-limiting enzyme of fatty acid oxidation. A single ip injection of cerulenin significantly reduced body weight and increased core temperature without significantly reducing food intake. In situ hybridization study revealed that a single injection of cerulenin did not affect the expression of orexigenic neuropeptide mRNA. Cerulenin’s effect on CPT-1 activity was biphasic in the liver and muscle: early suppression during the first 1 h and late stimulation in the 3–5 h after ip treatment. In vitro cerulenin treatment reduced CPT-1 activity, which was overcome by cotreating with catecholamine. Intracerebroventricular injection of cerulenin increased CPT-1 activity significantly in soleus muscle, and this effect was sustained for up to 3 h. Pretreatment with α-methyl-p-tyrosine inhibited the cerulenin-induced increase in core temperature and the late-phase stimulating effect of cerulenin on CPT-1 activity. In adrenalectomized mice, cerulenin also increased the activity. In vivo cerulenin treatment enhanced muscle CPT-1 activity in monosodium glutamate-treated arcuate nucleus lesioned mice but not in gold thioglucose-treated ventromedial hypothalamus lesioned mice. These findings suggest that cerulenin-induced late-phase stimulating effects on CPT-1 activity and energy expenditure is mediated by the activation of innervated sympathetic nervous system neurons through the firing of undefined neurons of the ventromedial hypothalamus, rather than the arcuate nucleus.
Tumor Suppressor Menin Regulates Expression of Insulin-Like Growth Factor Binding Protein 2
Authors: La Ping , Schnepp Robert W. , D. Petersen Clark , C. Silva Albert , Hua Xianxin
Published: March 2004

Multiple endocrine neoplasia type I (MEN1) is an inherited tumor syndrome characterized by development of tumors in multiple endocrine organs. The gene mutated in MEN1 patients, Men1, encodes a nuclear protein, menin. Menin interacts with several transcription factors and inhibits their activities. However, it is unclear whether menin is essential for the repression of the expression of endogenous genes. Here, using menin-null cells, we show that menin is essential for repression of the endogenous IGFBP-2, a gene that can regulate cell proliferation. Additionally, complementation of menin-null cells with wild-type menin, but not with a MEN1 disease-related point mutant, restores the function of menin in repressing IGFBP-2. Consistent with this, the promoter of IGFBP-2 is repressed by wild-type menin, but not by a MEN1-related point mutant. Menin also alters the structure of the chromatin surrounding the promoter of the IGFBP-2 gene, as demonstrated by the deoxyribonuclease I hypersensitivity assay. Furthermore, nuclear localization signals in menin are crucial for repressing the expression of IGFBP-2. Together, these results suggest that menin regulates the expression of the endogenous IGFBP-2 gene at least in part through the promoter of IGFBP-2.
The Cerberus/Dan-family protein Charon is a negative regulator of Nodal signaling during left-right patterning in zebrafish
Authors: Hashimoto Hisashi , Rebagliati Michael , Ahmad Nadira , Muraoka Osamu , Kurokawa Tadahide , Hibi Masahiko , Suzuki Tohru
Published: March 2004

We have isolated a novel gene, charon, that encodes a member of the Cerberus/Dan family of secreted factors. In zebrafish, Fugu and flounder, charon is expressed in regions embracing Kupffer's vesicle,which is considered to be the teleost fish equivalent to the region of the mouse definitive node that is required for left-right (L/R) patterning. Misexpression of Charon elicited phenotypes similar to those of mutant embryos defective in Nodal signaling or embryos overexpressing Antivin(Atv)/Lefty1, an inhibitor for Nodal and Activin. Charon also suppressed the dorsalizing activity of all three of the known zebrafish Nodal-related proteins (Cyclops,Squint and Southpaw), indicating that Charon can antagonize Nodal signaling. Because Southpaw functions in the L/R patterning of lateral plate mesoderm and the diencephalon, we asked whether Charon is involved in regulating L/R asymmetry. Inhibition of Charon's function by antisense morpholino oligonucleotides (MOs) led to a loss of L/R polarity, as evidenced by bilateral expression of the left side-specific genes in the lateral plate mesoderm (southpaw, cyclops, atv/lefty1, lefty2 and pitx2) and diencephalon (cyclops, atv/lefty1 and pitx2), and defects in early (heart jogging)and late (heart looping) asymmetric heart development, but did not disturb the notochord development or the atv/lefty1-mediated midline barrier function. MO-mediated inhibition of both Charon and Southpaw led to a reduction in or loss of the expression of the left side-specific genes,suggesting that Southpaw is epistatic to Charon in left-side formation. These data indicate that antagonistic interactions between Charon and Nodal(Southpaw), which take place in regions adjacent to Kupffer's vesicle, play an important role in L/R patterning in zebrafish.
Nuclear import and activity of histone deacetylase in Xenopus oocytes is regulated by phosphorylation
Authors: Smillie David A. , Llinas Alexander J. , Ryan James T. P. , Kemp Graham D. , Sommerville John
Published: March 2004

Most of the histone deacetylase (HDAC) activity detected in oocytes and early embryos of Xenopus can be accounted for by the presence of a protein complex that contains the maternal HDACm protein. This complex appears to fulfil the conditions required of a `deposition' histone deacetylase, its primary function being to deacetylate the core histones incorporated into newly-synthesized chromatin during the rapid cell cycles leading up to blastula. A major event in the assembly and accumulation of the HDAC complex is the translocation of the HDACm protein into the germinal vesicle during oogenesis. Here we examine the features of HDACm that are responsible for its nuclear uptake and enzyme activity, identifying the charged C-terminal domain as a target for modification by phosphorylation. Whereas, one phosphorylation site lying within the putative nuclear localization signal, T445, is required for efficient nuclear import of a GST-carboxy-tail fusion, two others, S421 and S423, appear to effect release from the import receptors. Although overexpression of recombinant HDACm in oocytes leads to premature condensation of endogenous chromatin, this effect is abrogated in vivo by mutation of S421A and S423A. Thus, both translocation and activity of HDACm appear to be regulated by specific phosphorylation events. These results have implications for techniques involving the transfer of somatic nuclei into enucleated oocytes.
Cell type-specific recruitment ofDrosophilaLin-7 to distinct MAGUK-based protein complexes defines novel roles for Sdt and Dlg-S97
Authors: Bachmann André , Timmer Marco , Sierralta Jimena , Pietrini Grazia , Gundelfinger Eckart D. , Knust Elisabeth , Thomas Ulrich
Published: March 2004

Stardust (Sdt) and Discs-Large (Dlg) are membrane-associated guanylate kinases (MAGUKs) involved in the organization of supramolecular protein complexes at distinct epithelial membrane compartments in Drosophila. Loss of either Sdt or Dlg affects epithelial development with severe effects on apico-basal polarity. Moreover, Dlg is required for the structural and functional integrity of synaptic junctions. Recent biochemical and cell culture studies have revealed that various mammalian MAGUKs can interact with mLin-7/Veli/MALS, a small PDZ-domain protein. To substantiate these findings for their in vivo significance with regard to Sdt- and Dlg-based protein complexes, we analyzed the subcellular distribution of Drosophila Lin-7 (DLin-7) and performed genetic and biochemical assays to characterize its interaction with either of the two MAGUKs. In epithelia, Sdt mediates the recruitment of DLin-7 to the subapical region, while at larval neuromuscular junctions, a particular isoform of Dlg, Dlg-S97, is required for postsynaptic localization of DLin-7. Ectopic expression of Dlg-S97 in epithelia, however, was not sufficient to induce a redistribution of DLin-7. These results imply that the recruitment of DLin-7 to MAGUK-based protein complexes is defined by cell-type specific mechanisms and that DLin-7 acts downstream of Sdt in epithelia and downstream of Dlg at synapses.
Length control is determined by the pattern of cytoskeleton
Authors: Kharitonova Margarita A. , Vasiliev Jury M.
Published: March 2004

In our previous experiments with linear strips of adhesive substrate, we found that elongated cultured fibroblasts preserve their length regardless of cell width and the number of cytoplasmic processes. This constancy of length was called `length control'. In contrast to fibroblasts, single cultured epitheliocytes have nearly discoid shape on the plane substrata and have no length-controlling mechanism: their length on the narrow strips of adhesive substrate increased significantly in comparison with the diameter on the plane substrate. These results suggested that control of length is cell specific. An alternative suggestion is that length control is associated not with the cell type but with the cell cytoskeletal pattern (namely, with epithelioid circular actin bundles or straight actin bundles). Experiments described in this paper were made to choose between these two suggestions. Mouse embryo fibroblasts spreading on the planar substrate first acquire discoid epithelioid shape with a circular actin bundle. Only later did they acquire a polarized shape with straight actin bundles. Polarized, fully spread fibroblasts temporarily acquire discoid epithelioid shape when treated with the Taxol, disorganizing microtubules. However, epithelial discoid cells can be transformed into elongated fibroblast-like cells by scatter factor (HGF/SF; a cytokine) and by agents inhibiting Rho kinase. These reversible transitions from fibroblastic to epithelioid shape and vice versa were accompanied by a corresponding disappearance and appearance of length control. Fibroblasts with stress fibers destroyed by the Rho-kinase inhibitor Y27632 became considerable longer on the adhesive strips than on the plane while retaining a near-polarized shape. Thus, length control is typical not of the cell origin but of the cell phenotype (i.e. for polarized cells with microtubules and intact actin cytoskeleton).
Preparation of Carbon Spheres Composed of Entangled Fibers at Low Temperature
Authors: Ni Youbao , Shao Mingwang , Zhang Wu , Wu Zhengcui
Published: March 2004

In this paper, we report a new mild reaction route to prepare carbon spheres composed of entangled fibers. The reaction was carried out at 250 °C for 24 h using sodium and polytetrafluorethylene as reactants and benzene as solvent. A possible formation mechanism is proposed.
Immobilized 1,3-Dialkylimidazolium Salts as New Interface in HPLC Separation
Authors: Liu Shu-Juan , Zhou Feng , Zhao Liang , Xiao Xiao-Hua , Liu Xia , Jiang Sheng-Xiang
Published: March 2004

Silica particle chemically modified with ionic liquid is used for the first time as the stationary phase in HPLC for the separation of alkaloids following a dual mechanism.
Electrochemical Studies of Silver Nanoparticles Tethered on Silica Sphere
Authors: Jiang Zhong-jie , Liu Chun-yan , Li Yong-jun
Published: March 2004

A good approach has been developed to study the electrochemical behavior of metal particles in sol. The technique to tether silver particles on silica sphere was established for the measurement of electrochemical behavior, which efficiently avoided the flocculation of colloidal metal particles in an electrolyte solution.
Controlling Wall Thickness of Silica Nanotubes within 4-nm Precision
Authors: Ji Qingmin , Iwaura Rika , Shimizu Toshimi
Published: March 2004

A tubular template self-assembled from secondary ammonium hydrochloride of a peptidic lipid was used for sol-gel transcription of tetraethoxysilane (TEOS). Very mild catalytic function of the terminal group enabled us to control the wall thickness of the resultant silica nanotubes within 4-nm precision, depending on the amount of TEOS added.
Adsorption of Carbon Dioxide on Amine Modified SBA-15 in the Presence of Water Vapor
Authors: Hiyoshi Norihito , Yogo Katsunori , Yashima Tatsuaki
Published: March 2004

Novel CO2 adsorbents were prepared by grafting of various aminosilanes on mesoporous silica SBA-15. CO2 adsorption capacities of aminosilane modified SBA-15 in the presence of water vapor were comparable to those in the absence of water vapor. It was found that efficiency of amine increased with increasing surface density of amine.
A New Nickel Coordination Polymer with Dynamic Channels that Mechanically Capture and Release Including Guest Molecules Responding to a Temperature Variation
Authors: Kondo Mitsuru , Shimizu Yusuke , Miyazawa Makoto , Irie Yasuhiko , Nakamura Akira , Naito Tetsuyoshi , Maeda Kenji , Uchida Fumio , Nakamoto Tadahiro , Inaba Akira
Published: March 2004

A new 1-D nickel(II) coordination polymer with dynamic channels was prepared and characterized. This compound has two structural phases that are switched by a temperature variation. The closed channel created at the low temperature mechanically captures the including guests in the channels.
Dynamic Microscopic Extraction of Europium(III) with 2-Thenoyltrifluoroacetone Observed as Random Fluorescence Flashes at Dodecane–Water Interface
Authors: Takata Ayaka , Tsukahara Satoshi , Watarai Hitoshi
Published: March 2004

Many random circular flashes of Eu(III) fluorescence (8–23 μm in diameter) appeared at the interface in the extraction of Eu(III) with 2-thenoyltrifluoroacetone (Htta) into dodecane, when a Eu3+ aqueous solution was added after pre-distribution of Htta in the aqueous phase. The flash was caused by the interfacial reaction between a pre-generated micro-aggregate of Eu(tta)2+ in the aqueous phase and excess Htta in the dodecane phase. The interfacial reaction produced more fluorescent Eu(tta)3, which diffused away into the dodecane phase.
The sheep as a model for coronary artery bypass surgery
Authors: Shofti R. , Zaretzki A. , Cohen E. , Engel A. , Bar-El Y.
Published: March 2004

The sheep is considered to be a suitable model for cardiovascular surgery because of its ease of handling, size, and vascular anatomy which bears close resemblance to the human. Several difficulties, however, have limited the use of the sheep for such a purpose—mainly the high infection rate resulting from median sternotomy incision and its susceptibility to intractable ventricular fibrillation (VF) with the slightest manipulation of the heart, and even the risk of short periods of myocardial ischaemia. We have used the sheep model extensively to perform coronary artery bypass surgery and were successful in overcoming these difficulties. Fifty-seven adult female sheep were used to test a new anastomotic device for the creation of a sutureless connection between venous and arterial grafts and the coronary arteries. The study required full access to the heart and great vessels and mobilization of one of the internal mammary arteries. Changing to the left lateral thoracotomy (LLT) approach solved the initial fatal problems of postoperative infected median sternotomy incisions. Aggressive prophylactic treatment with anti-arrhythmic drugs, maintenance of normothermia and myocardial preconditioning rendered the heart much less vulnerable to manipulations and ischaemia. These measures have reduced the mortality rate from 45% to 0% ( P <0.0001). With specific operative techniques and pharmaceutical interventions, the sheep can be effectively and safely used as a model for coronary artery surgery.
Videoendoscopic endotracheal intubation of the rat
Authors: Clary E. M. , O'Halloran E. K. , de la Fuente S. G. , Eubanks S.
Published: March 2004

Mechanical ventilation is essential to the proper maintenance of anaesthesia in research animals undergoing laparoscopic research investigations with prolonged pneumoperitoneum. Ventilatory assistance is greatly aided by endotracheal intubation, which in rats can be a challenging procedure with a substantial risk of complication. The difficulty of the procedure arises primarily from the limited exposure and access to the laryngeal opening. We describe a simple and safe technique for endotracheal intubation in the rat that permits the introduction of a large-bore tube under direct visualization using equipment commonly found in the endosurgical research setting.