bluuebunny/crossref_metadata_2025 huggingface dataset:
Blocking of the Alpha Interferon-Induced Jak-Stat Signaling Pathway by Japanese Encephalitis Virus Infection
Authors: Lin Ren-Jye , Liao Ching-Len , Lin Elong , Lin Yi-Ling
Published: August 2004

The induction of alpha/beta interferon (IFN-α/β) is a powerful host defense mechanism against viral infection, and many viruses have evolved strategies to overcome the antiviral effects of IFN. In this study, we found that IFN-α had only some degree of antiviral activity against Japanese encephalitis virus (JEV) infection, in contrast to another flavivirus, dengue virus serotype 2, which was highly sensitive to IFN-α in the cultured cell system. JEV infection appeared to render cells resistant to IFN-α since the IFN-α-induced luciferase reporter activity driven by the IFN-stimulated response element (ISRE) was gradually reduced as the JEV infection progressed. Since the biological activities of IFNs are triggered by the Janus kinase (Jak) signal transducer and activation of transcription (Stat) signaling cascade, we then studied the activation of Jak-Stat pathway in the virus-infected cells. The IFN-α-stimulated tyrosine phosphorylation of Stat1, Stat2, and Stat3 was suppressed by JEV in a virus replication and de novo protein synthesis-dependent manner. Furthermore, JEV infection blocked the tyrosine phosphorylation of IFN receptor-associated Jak kinase, Tyk2, without affecting the expression of IFN-α/β receptor on the cell surface. Consequently, expression of several IFN-stimulated genes in response to IFN-α stimulation was also reduced in the JEV-infected cells. Overall, our findings suggest that JEV counteracts the effect of IFN-α/β by blocking Tyk2 activation, thereby resulting in inhibition of Jak-Stat signaling pathway.
Change of Tropism of SL3-2 Murine Leukemia Virus, Using Random Mutational Libraries
Authors: Bahrami Shervin , Duch Mogens , Pedersen Finn Skou
Published: August 2004

SL3-2 is a polytropic murine leukemia virus with a limited species tropism. We cloned the envelope gene of this virus, inserted it into a bicistronic vector, and found that the envelope protein differs from other, similar envelope proteins that also utilize the polytropic receptor (Xpr1) in that it is severely impaired in mediating infection of human and mink cells. We found that two adjacent amino acid mutations (G212R and I213T), located in a previously functionally uncharacterized segment of the surface subunit, are responsible for the restricted tropism of the SL3-2 wild-type envelope. By selection from a two-codon library, several hydrophobic amino acids at these positions were found to enable the SL3-2 envelope to infect human TE 671 cells. In particular, an M212/V213 mutant had a titer at least 6 orders of magnitude higher than that of the wild-type envelope for human TE 671 cells and infected human, mink, and murine cells with equal efficiencies. Notably, these two amino acids are not found at homologous positions in known murine leukemia virus isolates. Functional analysis and library selection were done on the basis of sequence and tropism analyses of the SL3-2 envelope gene. Similar approaches may be valuable in the design and optimization of retroviral envelopes with altered tropisms for biotechnological purposes.
Induction of Cellular Immune Responses to Simian Immunodeficiency Virus Gag by Two Recombinant Negative-Strand RNA Virus Vectors
Authors: Nakaya Yurie , Nakaya Takaaki , Park Man-Seong , Cros Jerome , Imanishi Jiro , Palese Peter , García-Sastre Adolfo
Published: August 2004

A recombinant Newcastle disease virus (rNDV) expressing simian immunodeficiency virus (SIV) Gag protein (rNDV/SIVgag) was generated. The rNDV/SIVgag virus induced Gag-specific cellular immune responses in mice, leading to a specific anti-Gag antiviral immunity. This was evidenced by the inhibition of growth of recombinant vaccinia virus expressing an identical Gag antigen (rVac/SIVgag) but not of wild-type vaccinia virus in rNDV/SIVgag-immunized mice. Among intravenous, intraperitoneal, or intranasal immunization routes, intranasal administration induced the strongest protective response against challenge with rVac/SIVgag. We further demonstrated that these immune responses were greatly enhanced after booster immunization with recombinant influenza viruses expressing immunogenic portions of SIV Gag. The magnitude of the protective immune response correlated with the levels of cellular immune responses to Gag, which were still evident 9 weeks after immunization. These results suggest that rNDV and influenza virus vectors are suitable candidate vaccines against AIDS as well as against other infectious diseases.
Rabies Virus Stimulates Nitric Oxide Production and CXC Chemokine Ligand 10 Expression in Macrophages through Activation of Extracellular Signal-Regulated Kinases 1 and 2
Authors: Nakamichi Kazuo , Inoue Satoshi , Takasaki Tomohiko , Morimoto Kinjiro , Kurane Ichiro
Published: August 2004

Macrophages represent an essential part of innate immunity, and the viral infection of macrophages results in the release of multiple proinflammatory mediators, such as nitric oxide (NO), cytokines, and chemokines. This study was undertaken to define the molecular mechanism of macrophage activation in response to rabies virus (RV) infection. In RAW264 murine macrophage cells, a well-characterized macrophage model, RV replication was strictly restricted, whereas cell proliferation was significantly enhanced upon RV inoculation. Transcriptional analyses for the expression of inducible forms of NO synthase (iNOS), cytokines, and chemokines revealed that RV virions potentiate the gene expression of iNOS and CXC chemokine ligand 10 (CXCL10), a major chemoattractant of T helper cell type 1. However, RV stimulation had little or no effect on the expression profiles of proinflammatory cytokines and other types of chemokines. In macrophages stimulated with UV-inactivated RV virions, as well as infectious viruses, the phosphorylation of extracellular signal-regulated kinase (ERK) 1 and 2, members of the mitogen-activated protein kinase family, was significantly induced. Specific inhibitors of MAPK/ERK kinase reduced the RV-induced production of NO and CXCL10. Furthermore, the RV-induced activation of the ERK1/2 pathway was severely impaired by the neutralization of the endosomal and lysosomal pH environment with lysosomotropic agents, indicating that endocytosis is a key step leading to the activation of ERK1/2 signaling. Taken together, these results suggest that the ERK1/2-mediated signaling pathway plays a cardinal role in the selective activation of macrophages in response to RV virions, thereby regulating cellular functions during virus infection.
Epstein-Barr Virus (EBV) SM Protein Induces and Recruits Cellular Sp110b To Stabilize mRNAs and Enhance EBV Lytic Gene Expression
Authors: Nicewonger John , Suck Garnet , Bloch Donald , Swaminathan Sankar
Published: August 2004

Promyelocytic leukemia protein (PML) nuclear bodies or nuclear domain 10s (ND10s) are multiprotein nuclear structures implicated in transcriptional and posttranscriptional gene regulation that are disrupted during replication of many DNA viruses. Interferon increases the size and number of PML nuclear bodies and stimulates transcription of several genes encoding PML nuclear body proteins. Moreover, some PML nuclear body proteins colocalize at sites of viral DNA synthesis and transcription. In this study, the relationship between lytic Epstein-Barr virus (EBV) replication and Sp110b, a PML nuclear body protein, was investigated. Sp110b is shown to physically and functionally interact with the EBV protein SM. SM is expressed early in the EBV replicative cycle and posttranscriptionally increases the level of target EBV lytic transcripts. SM bound to Sp110b via two distinct sites in Sp110b in an RNA-independent manner. SM also specifically induced expression of Sp110b during lytic EBV replication and in several cell types. Exogenous expression of Sp110b synergistically enhanced SM-mediated accumulation of intronless and lytic viral transcripts. This synergistic effect was shown to be promoter independent, posttranscriptional, and the result of increased stabilization of target transcripts. Finally, inhibiting Sp110b expression decreased accumulation of an SM-responsive lytic EBV transcript in EBV-infected cells. These findings imply that SM induces Sp110b expression, binds to Sp110b, and utilizes the recruited Sp110b protein to increase the stability of lytic EBV transcripts, indicating that Sp110b is a component of the cellular machinery that EBV utilizes to enhance lytic EBV replication.
Global Host Immune Response: Pathogenesis and Transcriptional Profiling of Type A Influenza Viruses Expressing the Hemagglutinin and Neuraminidase Genes from the 1918 Pandemic Virus
Authors: Kash John C. , Basler Christopher F. , García-Sastre Adolfo , Carter Victoria , Billharz Rosalind , Swayne David E. , Przygodzki Ronald M. , Taubenberger Jeffery K. , Katze Michael G. , Tumpey Terrence M.
Published: August 2004

To understand more fully the molecular events associated with highly virulent or attenuated influenza virus infections, we have studied the effects of expression of the 1918 hemagglutinin (HA) and neuraminidase (NA) genes during viral infection in mice under biosafety level 3 (agricultural) conditions. Using histopathology and cDNA microarrays, we examined the consequences of expression of the HA and NA genes of the 1918 pandemic virus in a recombinant influenza A/WSN/33 virus compared to parental A/WSN/33 virus and to an attenuated virus expressing the HA and NA genes from A/New Caledonia/20/99. The 1918 HA/NA:WSN and WSN recombinant viruses were highly lethal for mice and displayed severe lung pathology in comparison to the nonlethal New Caledonia HA/NA:WSN recombinant virus. Expression microarray analysis performed on lung tissues isolated from the infected animals showed activation of many genes involved in the inflammatory response, including cytokine, apoptosis, and lymphocyte genes that were common to all three infection groups. However, consistent with the histopathology studies, the WSN and 1918 HA/NA:WSN recombinant viruses showed increased up-regulation of genes associated with activated T cells and macrophages, as well as genes involved in apoptosis, tissue injury, and oxidative damage that were not observed in the New Caledonia HA/NA:WSN recombinant virus-infected mice. These studies document clear differences in gene expression profiles that were correlated with pulmonary disease pathology induced by virulent and attenuated influenza virus infections.
Human Immunodeficiency Virus Type 1 Matrix Inhibits and Confers Cooperativity on Gag Precursor-Membrane Interactions
Authors: Perez-Caballero David , Hatziioannou Theodora , Martin-Serrano Juan , Bieniasz Paul D.
Published: August 2004

Human immunodeficiency virus type 1 (HIV-1) Gag multimerization and membrane binding are required for particle formation. However, it is unclear what constitutes a minimal plasma membrane-specific targeting signal and what role the matrix (MA) globular head and other Gag domains play in membrane targeting. Here, we use membrane flotation and microscopic analysis of Gag deletion mutants to demonstrate that the HIV-1 MA globular head inhibits a plasma membrane-specific targeting signal contained within the six amino-terminal MA residues. MA-mediated inhibition is relieved by concentration-dependent Gag multimerization and imparts a high degree of cooperativity on Gag-membrane association. This cooperativity may confer temporal and spatial regulation on HIV-1 assembly.
The Central Half of Pit2 Is Not Required for Its Function as a Retroviral Receptor
Authors: Bøttger Pernille , Pedersen Lene
Published: August 2004

The type III sodium-dependent phosphate (NaP
i
) cotransporter, Pit2, is a receptor for amphotropic murine leukemia virus (A-MuLV) and 10A1 MuLV. In order to determine what is sufficient for Pit2 receptor function, a deletion mutant lacking about the middle half of the protein was made. The mutant supported entry for both viruses, unequivocally narrowing down the identification of the sequence that is sufficient to specify the receptor functions of Pit2 to its N-terminal 182 amino acids and C-terminal 170 amino acids.
Mobility of the Human Immunodeficiency Virus (HIV) Receptor CD4 and Coreceptor CCR5 in Living Cells: Implications for HIV Fusion and Entry Events
Authors: Steffens Carolyn M. , Hope Thomas J.
Published: August 2004

The sequence of events leading to human immunodeficiency virus fusion and entry likely involves the recruitment of multiple receptor and coreceptor proteins to a specific complex by the viral envelope. Using fluorescence recovery after photobleaching technology, we find that both CD4 and CCR5 are mobile in the cell membrane. Interestingly, our findings also suggest that the seven-span transmembrane coreceptor is significantly more mobile than CD4 and requires membrane cholesterol for mobility.
Injecting drug use in Brighton, Liverpool, and London: best estimates of prevalence and coverage of public health indicators
Authors: Hickman Matthew , Higgins Vanessa , Hope Vivian , Bellis Mark , Tilling Kate , Walker Angeline , Henry John
Published: August 2004

Study objective:To estimate the prevalence of injecting drug use (IDU) in three cities in England and to measure the coverage of key public health indicators.

Design:Capture-recapture techniques with covariate effects.

Setting:Liverpool, Brighton, and 12 London boroughs, 2000/01.

Participants:IDU collated and matched across five data sources—community recruited survey, specialist drug treatment, arrest referral, syringe exchange, and accident and emergency—896 in Brighton, 1224 in Liverpool, and 6111 in London.

Main results:It is estimated that in 2000/01 the number and prevalence of IDU aged 15–44 was 2300 (95%CI 1500 to 3700) and 2.0% (95%CI% 1.3% to 3.2%) in Brighton; 2900 (95%CI 2500 to 5000) and 1.5% (95%CI 1.3% to 2.6%) in Liverpool; 16 700 (95%CI 13 800 to 21 600) and 1.2% (95%CI 1.0% to 1.6%) in 12 London boroughs; with a prevalence of 1.7% (95%CI 1.2% to 3.3%) in inner London. It is estimated that: less than one in four IDU are in treatment in the three areas; syringe exchange programmes covered about 25% of injections in Brighton and Liverpool and 20% in London; and that the annual opioid mortality rate among IDU was 2% in Brighton compared with less than 1% in Liverpool and London.

Conclusions:Credible estimates of the prevalence of injecting drug use (and key public health indicators) can be determined using covariate capture-recapture techniques. These suggest that: targets to double the number in treatment are possible: syringe distribution should be increased; and further attention, especially in Brighton, given to reducing overdose mortality.
Five American authors on wealth, poverty, and inequality
Authors: Kawachi Ichiro , Howden Chapman Philippa
Published: August 2004

There is much to be gleaned from novels concerning the links between wealth and power, inequality and corruption, poverty and illness. A student of social epidemiology will profit as much from close reading of these classics as from consulting textbooks on social stratification.
Heme transport exhibits polarity in Caco-2 cells: evidence for an active and membrane protein-mediated process
Authors: Uc Aliye , Stokes John B. , Britigan Bradley E.
Published: August 2004

Heme prosthetic groups are vital for all living organisms, but they can also promote cellular injury by generating reactive oxygen species. Therefore, intestinal heme absorption and distribution should be carefully regulated. Although a human intestine brush-border heme receptor/transporter has been suggested, the mechanism by which heme crosses the apical membrane is unknown. After it enters the cell, heme is degraded by heme oxygenase-1 (HO-1), and iron is released. We hypothesized that heme transport is actively regulated in Caco-2 cells. Cells exposed to hemin from the basolateral side demonstrated a higher HO-1 induction than cells exposed to hemin from the apical surface. Hemin secretion was more rapid than absorption, and net secretion occurred against a concentration gradient. Treatment of the apical membrane with trypsin increased hemin absorption by threefold, but basolateral treatment with trypsin had no effect on hemin secretion. Neither apical nor basolateral trypsin changed the paracellular pathway. We conclude that heme is acquired and transported in both absorptive and secretory directions in polarized Caco-2 cells. Secretion is via an active metabolic/transport process. Trypsin applied to the apical surface increased hemin absorption, suggesting that protease activity can uncover a process for heme uptake that is otherwise quiescent. These processes may be involved in preventing iron overload in humans.
Acidification reduces mitochondrial calcium uptake in rat cardiac mitochondria
Authors: Gursahani Hema I. , Schaefer Saul
Published: August 2004

Cardiac ischemia-reperfusion (I/R) injury is accompanied by intracellular acidification that can lead to cytosolic and mitochondrial calcium overload. However, the effect of cytosolic acidification on mitochondrial pH (pHm) and mitochondrial Ca2+(Cam2+) handling is not well understood. In the present study, we tested the hypothesis that changes in pHmduring cytosolic acidification can modulate Cam2+handling in cardiac mitochondria. pHmwas measured in permeabilized rat ventricular myocytes with the use of confocal microscopy and the pH-sensitive fluorescent probe carboxyseminaphthorhodafluor-1. The contributions of the mitochondrial Na+/H+exchanger (NHEm) and the K+/H+exchanger (KHEm) to pHmregulation were evaluated using acidification and recovery protocols to mimic the changes in pH observed during I/R. Cam2+transport in isolated mitochondria was measured using spectrophotometry and fluorimetry, and the mitochondrial membrane potential was measured using a tetraphenylphosphonium electrode. Cytosolic acidification (pH 6.8) resulted in acidification of mitochondria. The degree of mitochondrial acidification and recovery was found to be largely dependent on the activity of the KHEm. However, the NHEmwas observed to contribute to the recovery of pHmfollowing acidification in K+-free solutions as well as the maintenance of pHmduring respiratory inhibition. Acidification resulted in mitochondrial depolarization and a decrease in the rate of net Cam2+uptake, whereas restoration of pH following acidification increased Cam2+uptake. These findings are consistent with an important role for cytosolic acidification in determining pHmand Cam2+handling in cardiac mitochondria under conditions of Ca2+overload. Consequently, interventions that alter pHmcan limit Cam2+overload and injury during I/R.
Contributions of LFA-1 and Mac-1 to brain injury and microvascular dysfunction induced by transient middle cerebral artery occlusion
Authors: Arumugam Thiruma V. , Salter James W. , Chidlow John H. , Ballantyne Christie M. , Kevil Christopher G. , Granger D. Neil
Published: August 2004

Although the β2-integrins have been implicated in the pathogenesis of cerebral ischemia-reperfusion (I/R) injury, the relative contributions of the α-subunits to the pathogenesis of ischemic stroke remains unclear. The objective of this study was to determine whether and how genetic deficiency of either lymphocyte function-associated antigen-1 (LFA-1) or macrophage-1 (Mac-1) alters the blood cell-endothelial cell interactions, tissue injury, and organ dysfunction in the mouse brain exposed to focal I/R. Middle cerebral artery occlusion was induced for 1 h (followed by either 4 or 24 h of reperfusion) in wild-type mice and in mice with null mutations for either LFA-1 or Mac-1. Neurological deficit and infarct volume were monitored for 24 h after reperfusion. Platelet- and leukocyte-vessel wall adhesive interactions were monitored in cortical venules by intravital microscopy. Mice with null mutations for LFA-1 or Mac-1 exhibited significant reductions in infarct volume. This was associated with a significant improvement in the I/R-induced neurological deficit. Leukocyte adhesion in cerebral venules did not differ between wild-type and mutant mice at 4 h after reperfusion. However, after 24 h of reperfusion, leukocyte adhesion was reduced in both LFA-1- and Mac-1-deficient mice compared with their wild-type counterparts. Platelet adhesion was also reduced at both 4 and 24 h after reperfusion in the LFA-1- and Mac-1-deficient mice. These findings indicate that both α-subunits of the β2-integrins contribute to the brain injury and blood cell-vessel wall interactions that are associated with transient focal cerebral ischemia.
Effect of AT1 receptor antagonism on vascular and circulating inflammatory mediators in SHR: role of NF-κB/IκB system
Authors: Sanz-Rosa David , Oubiña M. Pilar , Cediel Eva , de las Heras Natalia , Vegazo Onofre , Jiménez Javier , Lahera Vicente , Cachofeiro Victoria
Published: August 2004

We investigated the role of angiotensin II in vascular and circulating inflammatory markers in spontaneously hypertensive rats (SHR). IL-1β, IL-6, and TNF-α aortic mRNA expression and plasma levels were measured in adult SHR untreated or treated with the angiotensin II receptor antagonist candesartan (2 mg·kg−1·day−1) or antihypertensive triple therapy (TT; in mg·kg−1·day−1: 20 hydralazine + 7 type 1 hydrochlorothiazide + 0.15 reserpine) for 10 wk. Likewise, aortic expression of NF-κB p50 subunit precursor p105 and its inhibitor (IκB) were measured. Age-matched Wistar-Kyoto rats (WKY) served as normotensive reference. High blood pressure levels were associated with increased ( P < 0.05) aortic mRNA expression of IL-1β, IL-6, and TNF-α. Hypertension was also accompanied by increased IL-1β and IL-6 plasma levels. No differences were observed in circulating TNF-α levels between SHR and WKY. SHR presented elevated aortic mRNA expression of the transcription factor NF-κB and reduction in its inhibitor, IκB. Candesartan decreased ( P < 0.05) blood pressure levels, aortic mRNA expression of IL-1β, IL-6, and TNF-α, and ( P < 0.05) IL-1β and IL-6 plasma concentration. However, although arterial pressure decrease was comparable for the treatments, TT only partially reduced the increments in inflammatory markers. In fact, candesartan-treated rats showed significantly lower levels of circulating and vascular inflammatory markers than TT-treated animals. The treatments increased IκB mRNA expression similarly. However, only candesartan reduced NF-κB mRNA expression. In summary, 1) SHR presented a vascular inflammatory process; 2) angiotensin II, and increased hemodynamic forces associated with hypertension, seems to be involved in stimulation of inflammatory mediators through NF-κB system activation; and 3) reduction of inflammatory mediators produced by candesartan in SHR could be partially due to both downregulation of NF-κB and upregulation of IκB.
ATP inhibits pump activity of lymph vessels via adenosine A1 receptor-mediated involvement of NO- and ATP-sensitive K+ channels
Authors: Kousai Akira , Mizuno Risuke , Ikomi Fumitaka , Ohhashi Toshio
Published: August 2004

We examined the effects of ATP on intrinsic pump activity in lymph vessels isolated from the rat. ATP caused significant dilation with a cessation of lymphatic pump activity. Removal of the endothelium or pretreatment with Nω-nitro-l-arginine methyl ester (l-NAME) significantly reduced ATP-induced inhibitory responses of lymphatic pump activity, whereas reduction was not suppressed completely by 10−6 M ATP. l-Arginine significantly restored ATP-induced inhibitory responses in the presence of l-NAME. ATP-induced inhibitory responses in lymph vessels with endothelium were also significantly, but not completely, suppressed by pretreatment with glibenclamide. 8-Cyclopentyl-1,3-dipropylxanthine (a selective adenosine A1 receptor antagonist), but not suramine (a P2X and P2Y receptor antagonist) or 3,7-dimethyl-1-proparglyxanthine (a selective adenosine A2 receptor antagonist), significantly decreased ATP-induced inhibitory responses. α,β-Methylene ATP (a selective P2X and P2Y receptor agonist) had no significant effect on lymphatic pump activity. In some lymph vessels with endothelium (24 of 30 preparations), adenosine also caused dose-dependent dilation with a cessation of lymphatic pump activity. l-NAME significantly reduced the inhibitory responses induced by the lower (3 × 10−8–3 × 10−7 M) concentrations of adenosine. Glibenclamide or 8-cyclopentyl-1,3-dipropylxanthine also significantly suppressed adenosine-induced inhibitory responses. These findings suggest that ATP-induced dilation and inhibition of pump activity of isolated rat lymph vessels are endothelium-dependent and -independent responses. ATP-mediated inhibitory responses may be, in part, related to production of endogenous nitric oxide, involvement of ATP-sensitive K+ channels, or activation of adenosine A1 receptors in lymphatic smooth muscle and endothelium.
Immunoglobulin treatment suppressed adoptively transferred autoimmune myocarditis in severe combined immunodeficient mice
Authors: Shioji Keisuke , Yuan Zuyi , Kita Toru , Kishimoto Chiharu
Published: August 2004

We investigated the suppressive effects of immunoglobulin (Ig) on effector T cells in autoimmune myocarditis. Treatment with Ig reduced production of the so-called T-helper type 1 (Th1) cytokines stimulated by concanavalin A or cardiac myosin in cultured lymph node (LN) cells from rats with myocarditis. The cytotoxic activities of LN cells from rats immunized with myosin and treated with Ig were reduced against cardiomyocytes and F-2 cells compared with those treated without Ig. The adoptive transfer of myocarditis from LN cells of Lewis rats with myocarditis to severe combined immunodeficient (SCID) recipients was successfully achieved. Treatment with Ig, but not with F(ab′)2fragments of Ig, reduced the mortality and severity of myocarditis in SCID recipient mice. Decreased ability of LN cells of Ig-treated rats, but not rats treated with F(ab′)2fragments, to transfer autoimmune myocarditis was also demonstrated. The findings of the present study suggest that autoimmune myocarditis was successfully transferred to SCID mice and that treatment with Ig ameliorated autoimmune myocarditis by inducing selective myosin unresponsiveness via the Fc portion, resulting in suppression of Th1 cytokine production and cytotoxic activities of LN cells, which operated together in the development of autoimmune myocarditis.
A high-fat diet during rat pregnancy or suckling induces cardiovascular dysfunction in adult offspring
Authors: Khan I. Y. , Dekou V. , Douglas G. , Jensen R. , Hanson M. A. , Poston L. , Taylor P. D.
Published: August 2004

Epidemiological and animal studies suggest that diet-induced epigenetic modifications in early life can contribute to development of the metabolic syndrome in adulthood. We previously reported features of the metabolic syndrome in adult offspring of rats fed a diet rich in animal fat during pregnancy and suckling. We now report a study to compare the relative effects of high-fat feeding during 1) pregnancy and 2) the suckling period in the development of these disorders. As observed previously, 6-mo-old female offspring of fat-fed dams suckled by the same fat-fed dams (OHF) demonstrated raised blood pressure, despite being fed a balanced diet from weaning. Female offspring of fat-fed dams “cross fostered” to dams consuming a control diet during suckling (OHF/C) demonstrated raised blood pressure compared with controls (OC) [systolic blood pressure (SBP; mmHg) means ± SE: OHF/C, 132.5 ± 3.0, n = 6 vs. OC, 119.0 ± 3.8, n = 7, P < 0.05]. Female offspring of controls cross fostered to dams consuming the fat diet (OC/HF) were also hypertensive [SBP (mmHg) 131.0 ± 2.5 mmHg, n = 6 vs. OC, P < 0.05]. Endothelium-dependent relaxation (EDR) of male and female OHF and OHF/C mesenteric small arteries was similar and blunted compared with OC ( P < 0.001). OC/HF arteries showed profoundly impaired EDR (OC/HF vs. OHF, P < 0.001). OHF/C and OC/HF demonstrated hyperinsulinemia and increased adiposity. Features of the metabolic syndrome in adult offspring of fat-fed rats can be acquired both antenatally and during suckling. However, exposure during pregnancy confers adaptive protection against endothelial dysfunction induced by maternal fat feeding during suckling.
Chronic low-frequency stimulation upregulates uncoupling protein-3 in transforming rat fast-twitch skeletal muscle
Authors: Putman Charles T. , Dixon Walter T. , Pearcey Jean A. , MacLean Ian M. , Jendral Michelle J. , Kiricsi Mónika , Murdoch Gordon K. , Pette Dirk
Published: August 2004

The purpose of this investigation was to examine the temporal changes in uncoupling protein (UCP)-3 expression, as well as related adaptive changes in mitochondrial density and fast-to-slow fiber type transitions during chronically enhanced contractile activity. We examined the effects of 1–42 days of chronic low-frequency electrical stimulation (CLFS), applied to rat tibialis anterior (TA) for 10 h/day, on the expression of UCP-3 and concomitant changes in myosin heavy chain (MHC) protein expression and increases in oxidative capacity. UCP-3 protein content increased from 1 to 12 days, reaching 1.5-fold over control ( P < 0.0005); it remained elevated for up to 42 days. In contrast, UCP-3 mRNA decreased in response to CLFS, reaching a level that was threefold lower than control ( P < 0.0007). The activities of the mitochondrial reference enzymes citrate synthase (EC 4.1.3.7) and 3-hydroxyacyl-CoA-dehydrogenase (EC 1.1.1.35), which are known to increase in proportion to mitochondrial density, progressively increased up to an average of 2.3-fold ( P < 0.00001). These changes were accompanied by fast-to-slow fiber type transitions, characterized by a shift in the pattern of MHC expression ( P <0.0002): MHCI and MHCIIa expression increased by 1.7- and 4-fold, whereas MHCIIb displayed a 2.4-fold reduction. We conclude that absolute increases in UCP-3 protein content in the early adaptive phase were associated with the genesis of mitochondria containing a normal complement of UCP-3. However, during exposure to long-term CLFS, mitochondria were generated with a lower complement of UCP-3 and coincided with the emergence of a growing population of oxidative type IIA fibers.
Impact of maternal stress on the transmammary transfer and protective capacity of herpes simplex virus-specific immunity
Authors: Yorty Jodi L. , Bonneau Robert H.
Published: August 2004

In adults, psychological stress regulates immune responsiveness in part via the increased levels of corticosterone that are produced as a result of hypothalamic-pituitary-adrenal (HPA) axis activation. However, there is a lack of knowledge as to the role such regulation may play in the neonate. Neonates are severely compromised in their ability to generate an immune response to pathogens encountered after birth and therefore rely heavily on maternally derived antibody acquired postnatally through the milk. This passive transfer of antibody is critical for protection of the neonate from severe herpes simplex virus (HSV) infection and mortality. Using a well-established postnatal restraint/light stress model, we determined whether maternal stress and the associated increases in corticosterone would affect the transmammary transfer of antibody and subsequent neonate susceptibility to HSV-associated mortality. Serum corticosterone levels were markedly increased in lactating mice subjected to the restraint/light stress, and increased levels of corticosterone were transferred through the milk of these stressed mothers to their neonates. Despite these increases in corticosterone, the transmammary transfer and accumulation of total and HSV-specific IgG in neonate serum remained intact. This milk-derived, HSV-specific antibody alone protected the neonate from systemic viral spread. Interestingly, postnatal maternal stress significantly increased neonate survival after HSV-2 infection despite no apparent alteration in viral spread. These studies demonstrate that although the transmammary transfer of antibody is unaffected by maternal stress, stress may be enhancing components of antiviral immunity that are effective in protecting neonates from HSV-associated mortality.
Enzymatic regulation of glucose disposal in human skeletal muscle after a high-fat, low-carbohydrate diet
Authors: Pehleman Tanya L. , Peters Sandra J. , Heigenhauser George J. F. , Spriet Lawrence L.
Published: August 2004

Whole body glucose disposal and skeletal muscle hexokinase, glycogen synthase (GS), pyruvate dehydrogenase (PDH), and PDH kinase (PDK) activities were measured in aerobically trained men after a standardized control diet (Con; 51% carbohydrate, 29% fat, and 20% protein of total energy intake) and a 56-h eucaloric, high-fat, low-carbohydrate diet (HF/LC; 5% carbohydrate, 73% fat, and 22% protein). An oral glucose tolerance test (OGTT; 1 g/kg) was administered after the Con and HF/LC diets with vastus lateralis muscle biopsies sampled pre-OGTT and 75 min after ingestion of the oral glucose load. The 90-min area under the blood glucose and plasma insulin concentration vs. time curves increased by 2-fold and 1.25-fold, respectively, after the HF/LC diet. The pre-OGTT fraction of GS in its active form and the maximal activity of hexokinase were not affected by the HF/LC diet. However, the HF/LC diet increased PDK activity (0.19 ± 0.05 vs. 0.08 ± 0.02 min−1) and decreased PDH activation (0.38 ± 0.08 vs. 0.79 ± 0.10 mmol acetyl-CoA·kg wet muscle−1·min−1) before the OGTT vs. Con. During the OGTT, GS and PDH activation increased by the same magnitude in both diets, such that PDH activation remained lower during the HF/LC OGTT (0.60 ± 0.11 vs. 1.04 ± 0.09 mmol acetyl-CoA·kg−1·min−1). These data demonstrate that the decreased glucose disposal during the OGTT after the 56-h HF/LC diet was in part related to decreased oxidative carbohydrate disposal in skeletal muscle and not to decreased glycogen storage. The rapid increase in PDK activity during the HF/LC diet appeared to account for the reduced potential for oxidative carbohydrate disposal.
A finite‐dimensional reduction method for slightly supercritical elliptic problems
Authors: Molle Riccardo , Passaseo Donato
Published: August 2004

We describe a finite‐dimensional reduction method to find solutions for a class of slightly supercritical elliptic problems. A suitable truncation argument allows us to work in the usual Sobolev space even in the presence of supercritical nonlinearities: we modify the supercritical term in such a way to have subcritical approximating problems; for these problems, the finite‐dimensional reduction can be obtained applying the methods already developed in the subcritical case; finally, we show that, if the truncation is realized at a sufficiently large level, then the solutions of the approximating problems, given by these methods, also solve the supercritical problems when the parameter is small enough.
Cortical Microvascular Remodeling in the Stenotic Kidney
Authors: Zhu Xiang-Yang , Chade Alejandro R. , Rodriguez-Porcel Martin , Bentley Michael D. , Ritman Erik L. , Lerman Amir , Lerman Lilach O.
Published: August 2004

Objective—

Mechanisms of renal injury distal to renal artery stenosis (RAS) remain unclear. We tested the hypothesis that it involves microvascular remodeling consequent to increased oxidative stress.

Methods and Results—

Three groups of pigs (n=6 each) were studied after 12 weeks of RAS, RAS+antioxidant supplementation (100 IU/kg vitamin E and 1 g vitamin C daily), or controls. The spatial density and tortuousity of renal microvessels (<500 μm) were tomographically determined by 3D microcomputed tomography. The in situ production of superoxide anion and the expression of vascular endothelial growth factor (VEGF), its receptor VEGFR-2, hypoxia-inducible-factor (HIF)-1α, von Hippel-Lindau (VHL) protein, and NAD(P)H oxidase (p47phox and p67phox subunits) were determined in cortical tissue. RAS and RAS+antioxidant groups had similar degrees of stenosis and hypertension. The RAS group showed a decrease in spatial density of cortical microvessels, which was normalized in the RAS+antioxidant group, as was arteriolar tortuousity. RAS kidneys also showed tissue fibrosis (by trichrome and Sirius red staining), increased superoxide anion abundance, NAD(P)H oxidase, VHL protein, and HIF-1α mRNA expression. In contrast, expression of HIF-1α, VEGF, and VEGFR-2 protein was downregulated. These were all significantly improved by antioxidant intervention.

Conclusions—

Increased oxidative stress in the stenotic kidney alters growth factor activity and plays an important role in renal microvascular remodeling, which can be prevented by chronic antioxidant intervention.
Exogenous NADPH Increases Cerebral Blood Flow Through NADPH Oxidase–Dependent and –Independent Mechanisms
Authors: Park Laibaik , Anrather Josef , Zhou Ping , Frys Kelly , Wang Gang , Iadecola Costantino
Published: August 2004

Objective—

NADPH, a substrate for the superoxide-producing enzyme NADPH oxidase, produces vasodilation in the cerebral circulation. However, the mechanisms of the effect have not been fully elucidated. We used a peptide inhibitor of NADPH oxidase (gp91ds-tat) and null mice lacking the gp91phox subunit of NADPH oxidase to examine the mechanisms of the cerebrovascular effects of exogenous NADPH.

Methods and Results—

Cerebral blood flow (CBF) was assessed by laser-Doppler flowmetry in anesthetized mice equipped with a cranial window. Superfusion with NADPH increased CBF (27% at 100 μmol/L) without affecting the EEG. The CBF increase was attenuated by the free-radical scavenger MnTBAP (−54%,
P
<0.05) but not by the H
2
O
2
scavenger catalase. The response was also attenuated by gp91ds-tat (−64%,
P
<0.05) and by the nitric oxide synthase inhibitor
N
ω
-nitro-
l
-arginine (−44%,
P
<0.05). The increase in CBF produced by NADPH was attenuated in gp91-null mice (−41%,
P
<0.05). NADPH increased production of reactive oxygen species, assessed by hydroethidine microfluorography, an effect blocked by MnTBAP or gp91ds-tat and not observed in gp91-null mice.

Conclusions—

These data suggest that the mechanisms of the CBF increases produced by exogenous NADPH are multifactorial and include NADPH oxidase–dependent and –independent factors.
Plasma Angiopoietin-1, Angiopoietin-2, Angiopoietin Receptor Tie-2, and Vascular Endothelial Growth Factor Levels in Acute Coronary Syndromes
Authors: Lee Kaeng W. , Lip Gregory Y.H. , Blann Andrew D.
Published: August 2004

Background—

Angiopoietin (Ang) -1 and -2, their receptor Tie-2, and vascular endothelial growth factor (VEGF) regulate angiogenesis and may be important in myocardial collateral development. Elevated levels of growth factors and their receptors are reported in myocardial infarction (MI), but changes after an acute coronary event are unknown.

Methods and Results—

Plasma Ang-1, Ang-2, Tie-2, and VEGF levels were measured on admission (baseline) and at 48 hours (acute stage) in 126 patients with acute coronary syndrome (82 MI, 44 unstable angina pectoris). Baseline levels were compared with those of 40 patients with stable angina and 40 healthy controls. Measurements were repeated in 38 MI patients at 6 and 18 weeks (chronic stage). Baseline Ang-2 and Tie-2 levels were highest in MI patients (
P
<0.001). Patients with MI and unstable angina pectoris had higher VEGF levels compared with stable angina patients and healthy control subjects (
P
<0.001). In patients with acute MI, serial changes in all indexes from baseline to 18 weeks were observed (all
P
<0.001). Ang-1 levels were unchanged from baseline to 6 weeks but were elevated at 18 weeks. Ang-2 changes followed a biphasic pattern, being higher at baseline and 6 weeks but lower at 48 hours and 18 weeks. Tie-2 levels increased from baseline and remained elevated in the chronic phase. VEGF peaked at 6 weeks and then decreased toward baseline at 18 weeks.

Conclusions—

Plasma Ang-2, Tie-2, and VEGF levels but not Ang-1 levels were increased in patients with acute coronary syndrome. Serial changes in the plasma levels and interrelationships among Ang-1, Ang-2, Tie-2, and VEGF levels from the acute to the chronic stages in MI may reflect the progressive stages of angiogenesis activity in the ischemic-necrotic myocardium in vivo.
Is the Impact of Hospital and Surgeon Volumes on the In-Hospital Mortality Rate for Coronary Artery Bypass Graft Surgery Limited to Patients at High Risk?
Authors: Wu Chuntao , Hannan Edward L. , Ryan Thomas J. , Bennett Edward , Culliford Alfred T. , Gold Jeffrey P. , Isom O. Wayne , Jones Robert H. , McNeil Barbara , Rose Eric A. , Subramanian Valavanur A.
Published: August 2004

Background—

Restriction of volume-based referral for CABG surgery to high-risk patients has been suggested, and earlier studies have reached different conclusions regarding volume-based referral for low-risk patients.

Methods and Results—

Patients who underwent isolated CABG surgery in New York from 1997 through 1999 (n=57 150) were separated into low-risk and moderate-to-high-risk groups with a predicted probability of in-hospital death of 2% as the cutoff point. The provider volume-mortality relationship was examined for both groups. For annual hospital volume thresholds between 200 and 600 cases, the adjusted ORs of in-hospital mortality for high-volume to low-volume hospitals ranged from 0.45 to 0.77 and were all significant for the low-risk group; for the moderate-to-high-risk group, ORs ranged from 0.62 to 0.91, and most were significant. The number needed to treat at higher-volume hospitals to avoid 1 death was greater for the low-risk group (a range of 114 to 446 versus 37 to 184). As the annual surgeon volume threshold increased from 50 to 150 cases, the ORs for high- to low-volume surgeons increased from 0.43 to 0.74 for the low-risk group; for the moderate-to-high-risk group, ORs ranged from 0.79 to 0.86. Compared with patients treated by surgeons with volumes of <125 in hospitals with volumes of <600, patients treated by higher-volume surgeons in higher-volume hospitals had a significantly lower risk of death; in particular, the OR was 0.52 for the low-risk group.

Conclusions—

For both low-risk and moderate-to-high-risk patients, higher provider volume is associated with lower risk of death.
Remodeling of Sinus Node Function in Patients With Congestive Heart Failure
Authors: Sanders Prashanthan , Kistler Peter M. , Morton Joseph B. , Spence Steven J. , Kalman Jonathan M.
Published: August 2004

Background—

Experimental and clinical studies have demonstrated diffuse atrial remodeling in congestive heart failure (CHF). We hypothesized that patients with CHF would demonstrate derangement of sinus node function.

Methods and Results—

Eighteen patients with symptomatic CHF (left ventricular ejection fraction, 26±5%) and 18 age-matched control subjects were studied. Under autonomic blockade, the following were evaluated: intrinsic sinus cycle length, corrected sinus node recovery time (CSNRT), sinoatrial conduction time, number and duration of fractionated electograms or double potentials along the crista terminalis, and location of the earliest sinus activity. Electroanatomic mapping was performed to evaluate the location and nature of the sinus node complex, to characterize sinoatrial propagation, and to evaluate conduction abnormalities and voltage amplitude along the crista terminalis. Patients with CHF demonstrated the following findings compared with age-matched control subjects: prolongation of the intrinsic sinus cycle length (
P
=0.005), prolongation of CSNRT (
P
<0.0001), caudal localization of sinus activity both during sinus rhythm (
P
=0.03) and after pacing (
P
=0.002), prolongation of sinoatrial conduction time (
P
=0.02), greater number (
P
<0.0001) and duration (
P
<0.0001) of fractionated electrograms or double potentials along the crista terminalis, loss of voltage amplitude along the crista terminalis (
P
=0.02), and abnormal and circuitous propagation of the sinus impulse.

Conclusions—

This study demonstrates that patients with CHF have significant sinus node remodeling characterized by anatomic and structural changes along the crista terminalis with a reduction in functional sinus node reserve. This finding may have implications for the development of clinical bradycardia in CHF and for the use of negatively chronotropic agents and pacing in this condition.
Extracellular Matrix Changes in Stented Human Coronary Arteries
Authors: Farb Andrew , Kolodgie Frank D. , Hwang Jin-Yong , Burke Allen P. , Tefera Kirubel , Weber Deena K. , Wight Thomas N. , Virmani Renu
Published: August 2004

Background—

Restenosis after stenting occurs secondary to the accumulation of smooth muscle cells (SMCs) and extracellular matrix (ECM), with the ECM accounting for >50% of the neointimal volume. The composition of the in-stent ECM has not been well characterized in humans.

Methods and Results—

Postmortem human coronary arteries (n=45) containing stents underwent histological assessment of neointimal proteoglycans, hyaluronan, collagen (types I and III), SMCs, and CD44 (a cell surface receptor for hyaluronan). The mean duration of stent implantation was 18.7 months; stents in place ≥3 to <9 months (n=17) were assigned to group 1, stents ≥9 to <18 months old (n=19) to group 2, and stents ≥18 months old (n=9) to group 3. In groups 1 and 2, neointimal versican and hyaluronan staining was strongly positive, colocalized with α-actin-positive SMCs, and was greater in intensity compared with group 3. Conversely, decorin staining was greatest in group 3. The neointima of both group 1 and 2 stents was rich in type III collagen, with reduced staining in group 3. Type I collagen staining was weakest in group 1 stents, with progressively stronger staining in groups 2 and 3. SMC density and stent stenosis were significantly reduced in group 3 stents compared with groups 1 and 2. CD44 staining colocalized with macrophages and was associated with increased neointimal thickness.

Conclusions—

The ECM within human coronary stents resembles a wound that is not fully healed until 18 months after deployment, followed by neointimal retraction. ECM contraction may be a target for therapies aimed at stent restenosis prevention.
Angiogenesis and Vasculogenesis Are Impaired in the Precocious-Aging
klotho
Mouse
Authors: Shimada Toshifumi , Takeshita Yoshiaki , Murohara Toyoaki , Sasaki Ken-ichiro , Egami Kimiyasu , Shintani Satoshi , Katsuda Yosuke , Ikeda Hisao , Nabeshima Yo-ichi , Imaizumi Tsutomu
Published: August 2004

Background—

The effects of aging on angiogenesis (vascular sprouting) and vasculogenesis (endothelial precursor cell [EPC] incorporation into vessels) are not well known. We examined whether ischemia-induced angiogenesis/vasculogenesis is altered in
klotho
(
kl
) mutant mice, an animal model of typical aging.

Methods and Results—

After unilateral hindlimb ischemia, laser Doppler blood-flow (LDBF) analysis revealed a decreased ischemic-normal LDBF ratio in
kl
mice. Tissue capillary density was also suppressed in
kl
mice (
+/+
>
+/kl
>
kl/kl
). Aortic-ring culture assay showed impaired angiogenesis in
kl/kl
mice, accompanied by reduced endothelium-derived nitric oxide release. Moreover, the rate of transplanted homologous bone marrow cells incorporated into capillaries in ischemic tissues (vasculogenesis) was lower in
kl/kl
mice than in wild-type (
+/+
) mice, which was associated with a decrease in the number of c-Kit
+
CD31
+
EPC-like mononuclear cells in bone marrow and in peripheral blood. Finally, the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor cerivastatin restored the impaired neovascularization in
kl/kl
mice, accompanied by an increase in c-Kit
+
CD31
+
cells in bone marrow and peripheral blood, and enhanced angiogenesis in the aortic-ring culture.

Conclusions—

Angiogenesis and vasculogenesis are impaired in
kl
mutant mice, a model of typical aging. Moreover, the age-associated impairment of neovascularization might be a new target of statin therapy.