bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Method Using a Laser Scanning Cytometer for Detection of
Mycobacteria
in Clinical Samples
Authors: Pina-Vaz Cidália , Costa-Oliveira Sofia , Rodrigues Acácio Gonçalves , Salvador Alexandre
Published: February 2004

In order to evaluate the capacity of laser scanning cytometry (LSC) to detect acid-fast bacilli directly on clinical samples, a comparison between Kinyoun-stained smears analyzed under light microscopy and propidium iodide-auramine-stained smears analyzed by LSC was performed. The results were compared with those for culture on BACTEC MGIT 960. LSC is a new, reliable methodology to detect
Mycobacteria
.
Bartholin's Gland Abscess Caused by
Brucella melitensis
Authors: Peled Neha , David Yohai , Yagupsky Pablo
Published: February 2004

We report herein a case of Bartholin's gland abscess caused by
Brucella melitensis
. Clinical microbiology laboratory workers in areas where this disease is endemic should be familiar with the bacteriological features of this organism and consider the possibility of a brucellar etiology in a broad range of clinical settings.
Two Cases of Continuous Ambulatory Peritoneal Dialysis-Associated Peritonitis Due to
Plesiomonas shigelloides
Authors: Woo Patrick C. Y. , Lau Susanna K. P. , Wong Samson S. Y. , Yuen Kwok-yung
Published: February 2004

We describe herein the first two cases of
Plesiomonas shigelloides
continuous ambulatory peritoneal dialysis-related peritonitis. Both patients presented with abdominal pain and turbid dialysis effluent with or without fever. Both recovered after 10 days of intraperitoneal administration of cefazolin and tobramycin. The route of transmission may have been direct contamination of the connection device or bacterial translocation through the gastrointestinal tract.
THE LORENTZ AND CPT VIOLATING EFFECTS ON H0→f+f-(ZZ,W+W-) DECAYS
Authors: ILTAN E. O.
Published: February 2004

We study the Lorentz and CPT violating effects on the ratio [Formula: see text] where BR LorVio ( BR SM ) is the branching ratios coming from the Lorentz violating effects (the SM), for the decays H0→f+f- (f = quarks and charged leptons) and H0→ZZ(W+W-). We observe that these new effects are too small to be detected, especially for f+f- output, since the corresponding coefficients are highly suppressed at the low energy scale.
QUANTUM MECHANICS IN INFINITE SYMPLECTIC VOLUME
Authors: ISIDRO JOSÉ M.
Published: February 2004

We quantise complex, infinite-dimensional projective space CP(ℋ). We apply the result to quantise a complex, finite-dimensional, classical phase space [Formula: see text] whose symplectic volume is infinite, by holomorphically embedding it into CP(ℋ). The embedding is univocally determined by requiring it to be an isometry between the Bergman metric on [Formula: see text] and the Fubini–Study metric on CP(ℋ). Then the Hilbert-space bundle over [Formula: see text] is the pullback, by the embedding, of the Hilbert-space bundle over CP(ℋ).
THE EIGENSPECTRUM AND HIDDEN SUPERSYMMETRY OF THE DIRAC OSCILLATOR IN 2+1 DIMENSIONS
Authors: JU GUO-XING , REN ZHONGZHOU
Published: February 2004

The eigenvalues and eigenfunctions of the Dirac oscillator in 2+1 dimension are given based on the analysis of asymptotic behaviour of the model. The hidden supersymmetry for the planar system is also constructed, which has the same form as the model in 3+1 dimension.
AN IMAGE SEGMENTATION VARIATIONAL MODEL WITH FREE DISCONTINUITIES AND CONTOUR CURVATURE
Authors: BELLETTINI GIOVANNI , MARCH RICCARDO
Published: February 2004

We introduce a functional for image segmentation which takes into account the transparencies (or shadowing) and the occlusions between objects located at different depths in space. By minimizing the functional, we try to reconstruct a piecewise smooth approximation of the input image, the contours due to transparencies, and the contours of the objects together with their hidden portions. The functional includes a Mumford–Shah type energy and a term involving the curvature of the contours. The variational properties of the functional are studied, as well as its approximation by Γ-convergence. The comparison with the Nitzberg–Mumford variational model for segmentation with depth is also discussed.
FLUX SPIKES IN VISCOUS FLOWS
Authors: TAN BAI-HE , WU ZI-NIU
Published: February 2004

In this paper we will study the condition for the occurrence of flux spikes, such as momentum spikes for the Navier–Stokes equations. Flux spikes are observed in Computational Fluid Dynamics, but it is unknown what are the exact conditions at which they occur and whether they are physical or purely numerical. In the present paper we try to clarify these questions.
ENTANGLEMENT OF TWO COUPLED CHARGE QUBITS
Authors: PASHKIN YU. A. , TILMA T. , AVERIN D. V. , ASTAFIEV O. , YAMAMOTO T. , NAKAMURA Y. , NORI F. , TSAI J. S.
Published: February 2004

We have analyzed the entanglement of a system of two coupled charge qubits. We calculate the amount of entanglement using several different approaches. We show that in the ideal case the system remains entangled most of the time and the amount of entanglement reaches almost unity, i.e. the system becomes maximally entangled at certain instances.
PHYSICS OF SINGULAR POINTS IN QUANTUM MECHANICS
Authors: TSUTSUI IZUMI , FÜLÖP TAMÁS
Published: February 2004

Defects or junctions in materials serve as a source of interactions for particles, and in idealized limits they may be treated as singular points yielding contact interactions. In quantum mechanics, these singularities accommodate an unexpectedly rich structure and thereby provide a variety of physical phenomena, especially if their properties are controlled properly. Based on our recent studies, we present a brief review on the physical aspects of such quantum singularities in one dimension. Among the intriguing phenomena that the singularities admit, we mention strong versus weak duality, supersymmetry, quantum anholonomy (Berry phase), and a copying process by anomalous caustics. We also show that a partition wall as a singularity in a potential well can give rise to a quantum force which exhibits an interesting temperature behavior characteristic to the particle statistics.
Differential bile-pancreatic secretory effects of CCK-58 and CCK-8
Authors: Reeve Joseph R. , Wu S. Vincent , Keire David A. , Faull Kym , Chew Peter , Solomon Travis E. , Green Gary M. , Coskun Tamer
Published: February 2004

In this work, we 1) synthesized rat CCK-58, 2) determined the amounts and forms of rat CCK in whole blood after stimulation of its release by casein, 3) determined the potency of CCK-8 and CCK-58 peptides to displace labeled CCK-8 from CCKAand CCKBreceptors transfected into Chinese hamster ovary (CHO) cells, and 4) examined the biological actions of CCK-8 and rat CCK-58 in an anesthetized rat model. CCK-58 was the only detected endocrine form of CCK in rat blood. Synthetic rat CCK-58 was less potent than CCK-8 for displacing the label from CCKAand CCKBreceptors in transfected CHO cells. However, rat CCK-58 was more potent than CCK-8 for stimulation of pancreatic protein secretion in the anesthetized rat. In addition, CCK-58 but not CCK-8 stimulated fluid secretion in this anesthetized rat model. These data suggest that regions outside the COOH terminus of rat CCK-58 influence the expression of CCK biological activity. The presence of only CCK-58 in the circulation and the fact that its biological activity differs from CCK-8 suggests that CCK-58 deserves scrutiny in other physiological models of CCK activity.
Stomach-brain communication by vagal afferents in response to luminal acid backdiffusion, gastrin, and gastric acid secretion
Authors: Danzer Marion , Jocic Milana , Samberger Claudia , Painsipp Evelin , Bock Elisabeth , Pabst Maria-Anna , Crailsheim Karl , Schicho Rudolf , Lippe Irmgard T. , Holzer Peter
Published: February 2004

Vagal afferents play a role in gut-brain signaling of physiological and pathological stimuli. Here, we investigated how backdiffusion of luminal HCl or NH4OH and pentagastrin-stimulated acid secretion interact in the communication between rat stomach and brain stem. Rats were pretreated intraperitoneally with vehicle or appropriate doses of cimetidine, omeprazole, pentagastrin, dexloxiglumide (CCK1 receptor antagonist), and itriglumide (CCK2 receptor antagonist) before intragastric administration of saline or backdiffusing concentrations of HCl or NH4OH. Two hours later, neuronal activation in the nucleus of the solitary tract (NTS) and area postrema was visualized by c-Fos immunohistochemistry. Exposure of the rat gastric mucosa to HCl (0.15-0.5 M) or NH4OH (0.1-0.3 M) led to a concentration-dependent expression of c-Fos in the NTS, which was not related to gender, gastric mucosal injury, or gastropyloric motor alterations. The c-Fos response to HCl was diminished by cimetidine and omeprazole, enhanced by pentagastrin, and left unchanged by dexloxiglumide and itriglumide. Pentagastrin alone caused an omeprazole-resistant expression of c-fos, which in the NTS was attenuated by itriglumide and prevented by dexloxiglumide but in the area postrema was reduced by dexloxiglumide and abolished by itriglumide. We conclude that vagal afferents transmit physiological stimuli (gastrin) and pathological events (backdiffusion of luminal HCl or NH4OH) from the stomach to the brain stem. These communication modalities interact because, firstly, acid secretion enhances afferent signaling of gastric acid backdiffusion and, secondly, gastrin activates NTS neurons through stimulation of CCK1 receptors on vagal afferents and of CCK2 receptors on area postrema neurons projecting to the NTS.
Prevention of TNF-α-induced apoptosis in polyamine-depleted IEC-6 cells is mediated through the activation of ERK1/2
Authors: Bhattacharya Sujoy , Ray Ramesh M. , Johnson Leonard R.
Published: February 2004

It has been documented that polyamines play a critical role in the regulation of apoptosis in intestinal epithelial cells. We have recently reported that protection from TNF-α/cycloheximide (CHX)-induced apoptosis in epithelial cells depleted of polyamines is mediated through the inactivation of a proapoptotic mediator, JNK. In this study, we addressed the involvement of the MAPK pathway in the regulation of apoptosis after polyamine depletion of IEC-6 cells. Polyamine depletion by α-difluromethylornithine (DFMO) resulted in the sustained activation of ERK in response to TNF-α/CHX treatment. Pretreatment of polyamine-depleted IEC-6 cells with a cell membrane-permeable MEK1/2 inhibitor, U-0126, significantly inhibited TNF-α/CHX-induced ERK phosphorylation and significantly increased DNA fragmentation, JNK activity, and caspase-3 activity in response to TNF-α/CHX. Moreover, the dose dependency of U-0126-mediated inhibition of TNF-α/ CHX-induced ERK phosphorylation correlated with the reversal of the antiapoptotic effect of DFMO. IEC-6 cells expressing constitutively active MEK1 had decreased TNF-α/CHX-induced JNK phosphorylation and were significantly protected from apoptosis. Conversely, a dominant-negative MEK1 resulted in high basal activation of JNK, cytochrome c release, and spontaneous apoptosis. Polyamine depletion of the dominant-negative MEK1 cells did not prevent JNK activation or cytochrome c release and failed to confer protection from both TNF-α/CHX and camptothecin-induced apoptosis. Finally, expression of a dominant-negative mutant of JNK significantly protected IEC-6 cells from TNF-α/CHX-induced apoptosis. These data indicate that polyamine depletion results in the activation of ERK, which inhibits JNK activation and protects cells from apoptosis.
Secretagogue-stimulated pancreatic secretion is differentially regulated by constitutive NOS isoforms in mice
Authors: DiMagno Matthew J. , Hao Yibai , Tsunoda Yasuhiro , Williams John A. , Owyang Chung
Published: February 2004

Nitric oxide (NO) and NO synthase (NOS) play controversial roles in pancreatic secretion. NOS inhibition reduces CCK-stimulated in vivo pancreatic secretion, but it is unclear which NOS isoform is responsible, because NOS inhibitors lack specificity and three NOS isoforms exist: neuronal (nNOS), endothelial (eNOS), and inducible (iNOS). Mice having individual NOS gene deletions were used to clarify the NOS species and cellular interactions influencing pancreatic secretion. In vivo secretion was performed in anesthetized mice by collecting extraduodenal pancreatic duct juice and measuring protein output. Nonselective NOS blockade was induced with Nω-nitro-l-arginine (l-NNA; 10 mg/kg). In vivo pancreatic secretion was maximal at 160 pmol·kg-1·h-1CCK octapeptide (CCK-8) and was reduced by NOS blockade (45%) and eNOS deletion (44%). Secretion was unaffected by iNOS deletion but was increased by nNOS deletion (91%). To determine whether the influence of NOS on secretion involved nonacinar events, in vitro CCK-8-stimulated secretion of amylase from isolated acini was studied and found to be unaltered by NOS blockade and eNOS deletion. Influence of NOS on in vivo secretion was further examined with carbachol. Protein secretion, which was maximal at 100 nmol·kg-1·h-1carbachol, was reduced by NOS blockade and eNOS deletion but unaffected by nNOS deletion. NOS blockade by l-NNA had no effect on carbachol-stimulated amylase secretion in vitro. Thus constitutive NOS isoforms can exert opposite effects on in vivo pancreatic secretion. eNOS likely plays a dominant role, because eNOS deletion mimics NOS blockade by inhibiting CCK-8 and carbachol-stimulated secretion, whereas nNOS deletion augments CCK-8 but not carbachol-stimulated secretion.
IGF-I stimulates human intestinal smooth muscle cell growth by regulation of G1phase cell cycle proteins
Authors: Kuemmerle John F. , Zhou Huiping , Bowers Jennifer G.
Published: February 2004

Autocrine production of insulinlike growth factor-I (IGF-I) regulates growth of human intestinal muscle cells by activation of distinct phosphatidylinositol 3-kinase (PI3-kinase)-dependent and ERK1/2-dependent pathways. The aim of the present study was to determine the mechanisms by which IGF-I regulates the G1phase of the cell cycle and muscle cell proliferation. Incubation of quiescent cells with IGF-I stimulated time-dependent cell cycle progression measured by using fluorescence-activated cell sorting analysis and by incorporation of [3H]thymidine. Studies using a microarray-based approach were used initially to identify genes expressed in human intestinal muscle encoding proteins known to participate in the G1phase of the cell cycle that were regulated by IGF-I. Incubation of muscle cells for 24 h with IGF-I elicited greater than fivefold increase in the expression of cyclin D1 and greater than twofold increase in retinoblastoma protein (Rb1). IGF-I elicited a time-dependent increase in cyclin D1 protein levels mediated jointly by ERK1/2-dependent and PI3-kinase-dependent mechanisms. Increase in cyclin D1 levels was accompanied by a time-dependent increase in cyclin D1-dependent cyclin-dependent kinase-4 (CDK4) activity. IGF-I also elicited a rapid time-dependent increase in Rb-(Ser807/811) phosphorylation, the specific target of the cyclin D1-dependent CDK4 kinase, and a slower increase in total Rb protein levels. We conclude that IGF-I stimulates G1phase progression, DNA synthesis, and cell proliferation of human intestinal smooth muscle cells. Effects of IGF-I on proliferation are mediated jointly by ERK1/2-dependent and PI3-kinase-dependent pathways that regulate cyclin D1 levels, CDK4 activity, and Rb activity.
Effect of stent coating alone on in vitro vascular smooth muscle cell proliferation and apoptosis
Authors: Curcio Antonio , Torella Daniele , Cuda Giovanni , Coppola Carmela , Faniello Maria Concetta , Achille Francesco , Russo Viviana G. , Chiariello Massimo , Indolfi Ciro
Published: February 2004

Synthetic polymers, like methacrylate (MA) compounds, have been clinically introduced as inert coatings to locally deliver drugs that inhibit restenosis after stent. The aim of the present study was to evaluate the effects of MA coating alone on vascular smooth muscle cell (VSMC) growth in vitro. Stainless steel stents were coated with MA at the following doses: 0.3, 1.5, and 3 ml. Uncoated/bare metal stents were used as controls. VSMCs were cultured in dishes, and a MA-coated stent or an uncoated bare metal stent was gently added to each well. VSMC proliferation was assessed by bromodeoxyuridine (BrdU) incorporation. Apoptosis was analyzed by three distinct approaches: 1) annexin V/propidium iodide fluorescence detection; 2) DNA laddering; and 3) caspase-3 activation and PARP cleavage. MA-coated stents induced a significant decrease of BrdU incorporation compared with uncoated stents at both the low and high concentrations. In VSMCs incubated with MA-coated stents, annexin V/propidium iodide fluorescence detection showed a significant increase in apoptotic cells, which was corroborated by the typical DNA laddering. Apoptosis of VSMCs after incubation with MA-coated stents was characterized by caspase-3 activation and PARP cleavage. The MA-coated stent induced VSMC growth arrest by inducing apoptosis in a dose-dependent manner. Thus MA is not an inert platform for eluting drugs because it is biologically active per se. This effect should be taken in account when evaluating an association of this coating with antiproliferative agents for in-stent restenosis prevention.
Hexarelin protects rat cardiomyocytes from angiotensin II-induced apoptosis in vitro
Authors: Pang Jin-Jiang , Xu Rong-Kun , Xu Xiang-Bin , Cao Ji-Min , Ni Chao , Zhu Wen-Ling , Asotra Kamlesh , Chen Meng-Chin , Chen Chen
Published: February 2004

Loss of cardiomyocytes by apoptosis is proposed to cause heart failure. Angiotensin II (ANG II), an important neurohormonal factor during heart failure, can induce cardiomyocyte apoptosis. Inasmuch as hexarelin has been reported to have protective effects in this process, we examined whether hexarelin can prevent cardiomyocytes from ANG II-induced cell death. Cultured cardiomyocytes from neonatal rats were stimulated with ANG II. Apoptosis was evaluated using fluorescence microscopy, TdT-mediated dUTP nick-end labeling (TUNEL) method, flow cytometry, DNA laddering, and analysis of cell viability by (3,4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). It was found that incubation with 0.1 μmol/l ANG II for 48 h increased cardiomyocyte apoptosis. Administration of 0.1 μmol/l hexarelin significantly decreased this ANG II-induced apoptosis and DNA fragmentation and increased myocyte viability. To further investigate the underlying mechanisms, caspase-3 activity assay and mRNA expression of Bax, Bcl-2, and growth hormone secretagogue receptor (GHS-R; the supposed hexarelin binding site) were examined. GHS-R mRNA was abundantly expressed in cardiomyocytes and was upregulated after administration of hexarelin. These results suggest that hexarelin abates cardiomyocytes from ANG II-induced apoptosis possibly via inhibiting the increased caspase-3 activity and Bax expression induced by ANG II and by increasing the expression of Bcl-2, which is depressed by ANG II. Whether the upregulated expression of GHS-R induced by hexarelin is associated with this antiapoptotic effect deserves further investigation.
Are cardiovascular and sympathoadrenal effects of human “new pressor protein” preparations attributable to human coagulation β-FXIIa?
Authors: Papageorgiou Peter C. , Pourdjabbar Ali , Amfilochiadis Akis A. , Diamandis Eleftherios P. , Boomsma Frans , Osmond Daniel H.
Published: February 2004

“New pressor protein” (NPP) derived from normal human plasma is an extra renal enzyme that shares strong sequence homology with human coagulation β-FXIIa. Under our bioassay conditions, human NPP (10–20 μl plasma equivalent/∼300 g rat iv) can raise the systolic blood pressure (SBP) by 40–50 mmHg, the diastolic blood pressure (DBP) by 15–20 mmHg, and the heart rate (HR) by 70–90 beats/min. Plasma epinephrine (of adrenal medullary origin) and norepinephrine rise by about 50- and 10-fold, respectively. Because β-FXIIa is not normally associated with pressor properties, we endeavored to substantiate that the hypertensive effects of impure NPP preparations used in our experiments are attributable to their content of β-FXIIa. We carried out comparisons with highly purified (>90%) commercial human β-FXIIa and found that by gel filtration (Sephadex G-100 and G-75), NPP bioactivity appeared in the ∼30-kDa elution zone, consistent with the molecular mass of β-FXIIa. Retention time using fast-protein liquid chromatography anion exchange chromatography was identical. Molecular mass and comigration were confirmed by SDS-PAGE gel electrophoresis, and the recovered ∼30-kDa protein bands yielded β-FXIIa fragments identified by mass spectrometry. Matched doses of the NPP preparations produced dose-response curves very similar to those elicited by β-FXIIa with respect to increments of SBP, DBP, and HR, whereas plasma catecholamine increments were generally comparable. We propose that β-FXIIa is substantially, if not exclusively, responsible for the observed effects of our NPP preparations and that this points to a novel axis connecting the FXII coagulation cascade and the sympathoadrenal gland to other cardiovascular regulatory mechanisms.
Superoxide, H2O2, and iron are required for TNF-α-induced MCP-1 gene expression in endothelial cells: role of Rac1 and NADPH oxidase
Authors: Chen Xi-Lin , Zhang Qiang , Zhao Ruozhi , Medford Russell M.
Published: February 2004

Reactive oxygen species (ROS) play an important but not yet fully defined role in the expression of inflammatory genes such as monocyte chemoattractant protein (MCP)-1. We used complementary molecular and biochemical approaches to explore the roles of specific ROS and their molecular linkage to inflammatory signaling in endothelial cells. Adenovirus-mediated expression of superoxide dismutase and catalase inhibited TNF-α-induced MCP-1 gene expression, suggesting important roles of superoxide ([Formula: see text]) and H2O2in MCP-1 gene activation. In addition, the iron chelator 1,2-dimethyl-3-hydroxypyridin-4-one and the hydroxyl radical scavengers dimethylthiourea and dimethyl sulfoxide inhibited TNF-α-induced MCP-1 expression, suggesting important roles of iron and hydroxyl radicals in inflammatory signal activation. In contrast, scavenging of peroxynitrite with 5,10,15,20-tetrakis-(4-sulfonatophenyl)prophyrinato iron (III) chloride had no effect on TNF-α-induced MCP-1 expression. Inhibition of NADPH oxidase, the major oxidase responsible for [Formula: see text] generation, with diphenylene iodonium suppressed TNF-α-induced MCP-1 mRNA accumulation. Rac1 is an upstream signaling molecule for the activation of NADPH oxidase and [Formula: see text] generation. Expression of dominant negative N17Rac1 by adenovirus suppressed TNF-α-induced MCP-1 mRNA levels and MCP-1 protein secretion. Expression of N17Rac1 inhibited TNF-α-induced MCP-1 and NF-κB transcriptional activity. These data suggest that ROS such as superoxide and H2O2derived from Rac1-activated NADPH oxidase mediate TNF-α-induced MCP-1 expression in endothelial cells.
Decreased skeletal muscle pump activity in patients with postural tachycardia syndrome and low peripheral blood flow
Authors: Stewart Julian M. , Medow Marvin S. , Montgomery Leslie D. , McLeod Kenneth
Published: February 2004

Standing translocates thoracic blood volume into the dependent body. The skeletal muscle pump participates in preventing orthostatic intolerance by enhancing venous return. We investigated the hypothesis that skeletal muscle pump function is impaired in postural tachycardia (POTS) associated with low calf blood flow (low-flow POTS) and depends in general on muscle blood flow. We compared 12 subjects that have low-flow POTS with 10 controls and 7 patients that have POTS and normal calf blood flow using strain-gauge plethysmography to measure peripheral blood flow, venous capacitance, and calf muscle pump function. Blood volume was estimated by dye dilution. We found that calf circumference was reduced in low-flow POTS (32 ± 1 vs. 39 ± 3 and 43 ± 3 cm) and, compared with controls and POTS patients with normal blood flow, is related to the reduced fraction of calf venous capacity emptied during voluntary muscle contraction (ejection fraction, 0.52 ± 0.07 vs. 0.76 ± 0.07 and 0.80 ± 0.06). We found that blood flow was linearly correlated ( rp= 0.69) with calf circumference (used as a surrogate for muscle mass). Blood volume measurements were 2.2 ± 0.3 in low-flow POTS vs. 2.6 ± 0.5 in controls ( P = 0.17) and 2.4 ± 0.7 in normal-flow POTS patients. Decreased calf blood flow may reduce calf size in POTS and thereby impair the upright ejective ability of the skeletal muscle pump and further contribute to overall reduced blood flow and orthostatic intolerance in these patients.
Mechanisms of angiotensin II-induced expression of B2kinin receptors
Authors: Tan Yan , Hutchison Florence N. , Jaffa Ayad A.
Published: February 2004

Although the primary roles of the kallikreinkinin system and the renin-angiotensin system are quite divergent, they are often intertwined under pathophysiological conditions. We examined the effect of ANG II on regulation of B2kinin receptors (B2KR) in vascular cells. Vascular smooth muscle cells (VSMC) were treated with ANG II in a concentration (10—9-10—6M)- and time (0–24 h)-dependent manner, and B2KR protein and mRNA levels were measured by Western blots and PCR, respectively. A threefold increase in B2KR protein levels was observed as early as 6 h, with a peak response at 10—7M. ANG II (10—7M) also increased B2KR mRNA levels twofold 4 h after stimulation. Actinomycin D suppressed the increase in B2KR mRNA and protein levels induced by ANG II. To elucidate the receptor subtype involved in mediating this regulation, VSMC were pretreated with losartan (AT1receptor antagonist) and/or PD-123319 (AT2receptor antagonist) at 10 μM for 30 min, followed by ANG II (10—7M) stimulation. Losartan completely blocked the ANG II-induced B2KR increase, whereas PD-123319 had no effect. In addition, expression of B2KR mRNA levels was decreased in AT1Areceptor knockout mice. Finally, to determine whether ANG II stimulates B2KR expression via activation of the MAPK pathway, VSMC were pretreated with an inhibitor of p42/p44mapk(PD-98059) and/or an inhibitor of p38mapk(SB-202190), followed by ANG II (10—7M) for 24 h. Selective inhibition of the p42/p44mapkpathway significantly blocked the ANG II-induced increase in B2KR expression. These findings demonstrate that ANG II regulates expression of B2KR in VSMC and provide a rationale for studying the interaction between ANG II and bradykinin in the pathogenesis of vascular dysfunction.
Evidence of a role for TRPC channels in VEGF-mediated increased vascular permeability in vivo
Authors: Pocock T. M. , Foster R. R. , Bates D. O.
Published: February 2004

Vascular endothelial growth factor (VEGF) increases vascular permeability by stimulating endothelial Ca2+influx. Here we provide evidence that links VEGF-mediated increased permeability and endothelial intracellular Ca2+concentration ([Ca2+]i) with diacylglycerol (DAG)-mediated activation of the transient receptor potential channels (TRPCs). We used the Landis-Michel technique to measure changes in hydraulic conductivity ( Lp) and fluorescence photometry to quantify changes in endothelial [Ca2+]iin individually perfused Rana mesenteric microvessels in vivo and transfected nonendothelial cells in vitro. The membrane-permeant DAG analog 1-oleoyl-2-acetyl- sn-glycerol (OAG, 100 μM), which is known to increase Ca2+influx through TRPCs, transiently increased Lp3.8 ± 1.2-fold (from 1.6 ± 0.8 to 9.8 ± 2.7 × 10–7cm·s–1·cmH2O–1; P < 0.0001; n = 18). Protein kinase C inhibition by bisindolylmaleimide (1 μM) did not affect the OAG-induced increases in Lp. OAG also significantly increased microvascular endothelial [Ca2+]iin vivo ( n = 13; P < 0.0001), which again was not sensitive to protein kinase C inhibition. VEGF induced a transient increase in endothelial [Ca2+]iin human embryonic kidney cells (HEK-293) that were cotransfected with VEGF receptor 2 and TRPC-6 but not with control, VEGF receptor 2, or TRPC-6 expression vector alone ( P < 0.01; n = 9). Flufenamic acid, which has been shown to enhance activity of TRPC-6 but inhibit TRPC-3 and -7, enhanced the VEGF-mediated increase in Lpin approximately half of the vessels tested but inhibited the response in the other half of the vessels. These data provide evidence consistent with the hypothesis that VEGF increases vascular permeability via DAG-mediated Ca2+entry through TRPCs. Although the exact identities of the TRPCs remain to be confirmed, TRPC-6 appears to be a likely candidate in approximately half of the vessels.
Spatial and temporal control of angiogenesis and arterialization using focal applications of VEGF164and Ang-1*
Authors: Peirce Shayn M. , Price Richard J. , Skalak Thomas C.
Published: February 2004

Microvascular networks undergo patterning changes that determine and reflect functional adaptations during tissue remodeling. Alterations in network architectures are a result of complex and integrated signaling events. To understand how two growth factor signals interact to stimulate angiogenesis and arterialization, we engineered spatially directed microvascular pattern changes in vivo by using combinations of focally delivered exogenous growth factors. We implanted microdelivery beads containing recombinant vascular endothelial growth factor-164 (VEGF164) and recombinant angiopoietin-1* (Ang-1*) into the dorsal subcutaneous tissue of fully anesthetized male Fischer 344 rats implanted with backpack window chambers, and we quantified vascular patterning changes by using intravital microscopy, a combination of architectural metrics, and immunohistochemistry. Focal delivery of VEGF164caused spatially directed increases in both the total number and the density of vessels with diameters <25 μm 7 days after microbead implantation. Increases were maintained out to 14 days but were reduced to control values by day 21. The addition of Ang-1* on day 7 maintained these increases out to day 21, induced vessel order ratios comparable to control levels, and was accompanied by increases in the length density of smooth muscle α-actin-positive vessels. We achieved spatial control of patterning changes in vivo by using multisignal stimulation via focal delivery of exogenous growth factor combinations and conclude that Ang-1* administered subsequent to VEGF164stimulation induces vascular growth while maintaining a network pattern consistent with native patterns that persist in the presence of vehicle control stimulation.
Induction of myocardial infarcts of a predictable size and location by branch pattern probability-assisted coronary ligation in C57BL/6 mice
Authors: Ahn Dongchoon , Cheng Linda , Moon Chanil , Spurgeon Harold , Lakatta Edward G. , Talan Mark I.
Published: February 2004

The ability to create experimental myocardial infarctions of reproducible size and location is tantamount to progress in multiple facets of ischemic heart disease research. Branches of the mouse left main descending coronary artery penetrate the myocardium close to their origin and require “blind” ligation. Our objective was to develop a technique for ligation of nonvisible coronary artery branches to permit the reliable creation of infarcts of uniformly small size and location. From latex castings of the left coronary artery of C57BL/6J mice ( n = 53), we calculated the highest probability for the location of branch points of two of three left ventricular (LV) branches distal to the origin of the left main descending artery. On the basis of these anatomic probabilities, we blindly ligated two areas that were likely to be locations of these nonvisible LV branches. We were successful in producing two types of small transmural myocardial infarctions (16.04 ± 3.64 and 4.68 ± 1.47% of the LV) in 57% of attempts. Thus our branch pattern probability-assisted method permits routine creation of small infarcts of uniform size in the mouse.
Microlymphatic and tissue oxygen tension in the rat mesentery
Authors: Hangai-Hoger Nanae , Cabrales Pedro , Briceño Juan C. , Tsai Amy G. , Intaglietta Marcos
Published: February 2004

Oxygen phosphorescence quenching was used to measure tissue Po2of lymphatic vessels of 43.6 ± 23.1 μm (mean ± SD) diameter in tissue locations of the rat mesentery classified according to anatomic location. Lymph and adipose tissue Po2were 20.6 ± 9.1 and 34.1 ± 7.8 mmHg, respectively, with the difference being statistically significant. Rare microlymphatic vessels in connective tissue not surrounded by microvessels had a Po2of 0.8 ± 0.2 mmHg, whereas the surrounding tissue Po2was 3.0 ± 3.2 mmHg, with both values being significantly lower than those of adipose tissue. Lower of lymph fluid Po2relative to the surrounding tissue was also evident in paired measurements of Po2in the lymphatic vessels and perilymphatic adipose tissue, which was significantly lower than the Po2in paired adipose tissue. The Po2of the lymphatic fluid of the mesenteric microlymphatics is consistently lower than that of the surrounding adipose tissue by ∼11 mmHg; therefore, lymph fluid has the lowest Po2of this tissue. The disparity between lymph and tissue Po2is attributed to the microlymphatic vessel wall and lymphocyte oxygen consumption.
Dynamic changes of gene expression in hypoxia-induced right ventricular hypertrophy
Authors: Sharma Saumya , Taegtmeyer Heinrich , Adrogue Julia , Razeghi Peter , Sen Shiraj , Ngumbela Kholiswa , Essop M. Faadiel
Published: February 2004

Hypobaric hypoxia induces right ventricular hypertrophy. The relative contribution of pulmonary hypertension, decreased arterial oxygen, and neuroendocrine stimulation to the transcriptional profile of hypoxia-induced right ventricular hypertrophy is unknown. Whereas both ventricles are exposed to hypoxia and neuroendocrine stimulation, only the right ventricle is exposed to increased load. We postulated that right ventricular hypertrophy would reactivate the fetal gene transcriptional profile in response to increased load. We measured the expression of candidate genes in the right ventricle of rats exposed to hypobaric hypoxia (11% O2) and compared the results with the left ventricle. Hypoxia induced right ventricular hypertrophy without fibrosis. In the right ventricle only, atrial natriuretic factor transcript levels progressively increased starting at day 7. Metabolic genes were differentially regulated, suggesting a substrate switch from fatty acids to glucose during early hypoxia and a switch back to fatty acids by day 14. There was also a switch in myosin isogene expression and a downregulation of sarcoplasmic/endoplasmic ATPase 2a during early hypoxia, whereas later, both myosin isoforms and SERCA2a were upregulated. When the right and left ventricle were compared, the transcript levels of all genes, except for myosin isoforms and pyruvate dehydrogenase kinase-4, differed dramatically suggesting that all these genes are regulated by load. Our findings demonstrate that hypoxia-induced right ventricular hypertrophy transiently reactivates the fetal gene program. Furthermore, myosin iso-gene and pyruvate dehydrogenase kinase-4 expression is not affected by load, suggesting that either hypoxia itself or neuroendocrine stimulation is the primary regulator of these genes.
Neurogenic inflammation in mice deficient in heparin-synthesizing enzyme
Authors: Karlsen Tine V. , Iversen Vegard V. , Forsberg Erik , Kjellén Lena , Reed Rolf K. , Gjerde Eli-Anne B.
Published: February 2004

Mast cell activation, or neurogenic inflammation, is known to induce lowering of interstitial fluid pressure (Pif) and plasma protein extravasation (PPE) in several tissues from both rats and mice. To examine a possible role of connective tissue mast cells (CTMCs) in these inflammatory responses, we used mice with dysfunctional CTMCs due to lack of the N-deacetylase/ N-sulfotransferase-2 enzyme (NDST-2–/–). Pif and PPE were measured after challenge with compound 48/80 (C48/80), and Pif alone was measured after treatment either with capsaicin, substance P (SP), or calcitonin gene-related peptide (CGRP). Measurements of Pif in anesthetized (fentanyl/fluanison and midazolam, 1:1) mice were performed in paw skin with glass capillaries connected to a servo-controlled counterpressure system. PPE was measured with microdialysis by using hollow plasmapheresis fibers (cutoff at 3,000 kDa) placed subcutaneously on the back. Intravenous administration of C48/80 lowered Pif significantly ( P < 0.05) in NDST-2–/– mice (–1.67 ± 0.42 mmHg) compared with vehicle (–0.57 ± 0.17 mmHg) but the lowering was significantly ( P < 0.05) less compared with that of the NDST-2+/+ mice (–2.31 ± 0.47 mmHg). PPE was increased 300% after treatment with C48/80 in NDST-2+/+ mice, whereas there was no increase in PPE in NDST-2–/– mice. Capsaicin, SP, and CGRP lowered Pif significantly ( P < 0.05) compared with vehicle and to the same extent in both NDST-2+/+ and NDST-2–/– mice. We can conclude that although NDST-2–/– mice demonstrate an altered response in Pif after mast cell activation, there was no similar alteration after neurogenic inflammation. Therefore, we suggest that neurogenic inflammation in mouse skin is not exclusively dependent on intact CTMCs.
Muscle metabolism with blood flow restriction in chronic fatigue syndrome
Authors: McCully Kevin K. , Smith Sinclair , Rajaei Sheeva , Leigh John S. , Natelson Benjamin H.
Published: February 2004

The purpose of this study was to determine whether chronic fatigue syndrome (CFS) is associated with reduced blood flow and muscle oxidative metabolism. Patients with CFS according to Centers for Disease Control criteria ( n = 19) were compared with normal sedentary subjects ( n = 11). Muscle blood flow was measured in the femoral artery with Doppler ultrasound after exercise. Muscle metabolism was measured in the medial gastrocnemius muscle with 31P-magnetic resonance spectroscopy. Muscle oxygen saturation and blood volume were measured using near-infrared spectroscopy. CFS and controls were not different in hyperemic blood flow or phosphocreatine recovery rate. Cuff pressures of 50, 60, 70, 80, and 90 mmHg were used to partially restrict blood flow during recovery. All pressures reduced blood flow and oxidative metabolism, with 90 mmHg reducing blood flow by 46% and oxidative metabolism by 30.7% in CFS patients. Hyperemic blood flow during partial cuff occlusion was significantly reduced in CFS patients ( P < 0.01), and recovery of oxygen saturation was slower ( P < 0.05). No differences were seen in the amount of reduction in metabolism with partially reduced blood flow. In conclusion, CFS patients showed evidence of reduced hyperemic flow and reduced oxygen delivery but no evidence that this impaired muscle metabolism. Thus CFS patients might have altered control of blood flow, but this is unlikely to influence muscle metabolism. Furthermore, abnormalities in muscle metabolism do not appear to be responsible for the CFS symptoms.
Viral expression of insulin-like growth factor-I enhances muscle hypertrophy in resistance-trained rats
Authors: Lee Sukho , Barton Elisabeth R. , Sweeney H. Lee , Farrar Roger P.
Published: February 2004

Muscle hypertrophy is the product of increased drive through protein synthetic pathways and the incorporation of newly divided satellite cells. Gains in muscle mass and strength can be achieved through exercise regimens that include resistance training. Increased insulin-like growth factor-I (IGF-I) can also promote hypertrophy through increased protein synthesis and satellite cell proliferation. However, it is not known whether the combined effect of IGF-I and resistance training results in an additive hypertrophic response. Therefore, rats in which viral administration of IGF-I was directed to one limb were subjected to ladder climbing to test the interaction of each intervention on muscle mass and strength. After 8 wk of resistance training, a 23.3% increase in muscle mass and a 14.4% increase in peak tetanic tension (Po) were observed in the flexor hallucis longus (FHL). Viral expression of IGF-I without resistance training produced a 14.8% increase in mass and a 16.6% increase in Po in the FHL. The combined interventions produced a 31.8% increase in muscle mass and a 28.3% increase in Po in the FHL. Therefore, the combination of resistance training and overexpression of IGF-I induced greater hypertrophy than either treatment alone. The effect of increased IGF-I expression on the loss of muscle mass associated with detraining was also addressed. FHL muscles treated with IGF-I lost only 4.8% after detraining, whereas the untreated FHL lost 8.3% muscle mass. These results suggest that a combination of resistance training and overexpression of IGF-I could be an effective measure for attenuating the loss of training-induced adaptations.
Physical exercise can influence local levels of matrix metalloproteinases and their inhibitors in tendon-related connective tissue
Authors: Koskinen S. O. A. , Heinemeier K. M. , Olesen J. L. , Langberg H. , Kjaer M.
Published: February 2004

Microdialysis studies indicate that mechanical loading of human tendon tissue during exercise or training can affect local synthesis and degradation of type I collagen. Degradation of collagen and other extracellular matrix proteins is controlled by an interplay between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs). However, it is unknown whether local levels of MMPs and TIMPs are affected by tendon loading in humans in vivo. In the present experiment, six healthy young men performed 1 h of uphill (3%) treadmill running. Dialysate was collected from microdialysis probes (placed in the peritendinous tissue immediately anterior to the Achilles tendon) before, immediately after, 1 day after, and 3 days after an exercise bout. MMP-2 and MMP-9 were measured in dialysate by gelatin zymography, and amounts were quantified by densitometry in relation to total protein in the dialysate. TIMP-1 and TIMP-2 were analyzed by reverse gelatin zymography and semiquantitated visually. Pro-MMP-9 increased markedly after exercise and remained high for 3 days after exercise. Pro-MMP-2 dropped from the basal level immediately after exercise and remained low 1 day after exercise but was slightly elevated 3 days after exercise. The MMP-2 inhibitory activity of TIMP-1 was clearly elevated 1 and 3 days after exercise, and the MMP-2 inhibitory activity of TIMP-2 rose 1 day after loading. The present findings demonstrate enhanced interstitial amounts of MMPs and TIMPs after exercise in the human peritendinous tissue in vivo, and the magnitude and time pattern of these changes may well indicate that MMPs and TIMPs are playing a role in extracellular matrix adaptation to exercise in tendon tissue.
Opening the pericardium during pulmonary artery constriction improves cardiac function
Authors: Belenkie Israel , Sas Rozsa , Mitchell Jamie , Smith Eldon R. , Tyberg John V.
Published: February 2004

During acute pulmonary hypertension, both the pericardium and the right ventricle (RV) constrain left ventricular (LV) filling; therefore, pericardiotomy should improve LV function. LV, RV, and pericardial pressures and RV and LV dimensions and LV stroke volume (SV) were measured in six anesthetized dogs. The pericardium was closed, the chest was left open, and the lungs were held away from the heart. Data were collected at baseline, during pulmonary artery constriction (PAC), and after pericardiotomy with PAC maintained. PAC decreased SV by one-half. RV diameter increased, and septum-to-LV free wall diameter and LV area (our index of LV end-diastolic volume) decreased. Compared with during PAC, pericardiotomy increased LV area and SV increased 35%. LV and RV compliance (pressure-dimension relations) and LV contractility (stroke work-LV area relations) were unchanged. Although series interaction accounts for much of the decreased cardiac output during acute pulmonary hypertension, pericardial constraint and leftward septal shift are also important. Pericardiotomy can improve LV function in the absence of other sources of external constraint to LV filling.
Antioxidant intervention does not affect the response of plasma erythropoietin to short-term normobaric hypoxia in humans
Authors: Niess A. M. , Fehrenbach E. , Lorenz I. , Müller A. , Northoff H. , Dickhuth H.-H. , Schneider E. M.
Published: February 2004

Recent research has demonstrated that reactive oxygen species (ROS) participate in intracellular signaling processes initiated during hypoxia. We investigated the role of ROS in the response of plasma erythropoietin (Epo) to short-term normobaric hypoxia in humans. Twelve male subjects were exposed twice to 4 h of normobaric hypoxia (H; inspired oxygen fraction 12.5%) with a period of 6 wk between both experiments (H1 and H2). With the use of a randomized placebo-controlled crossover design, the subjects received orally a combination of the antioxidants all-rac-α-tocopherol (800 mg/day for 3 wk) and α-lipoic acid (600 mg/day for 2 wk) or placebo before H1 and H2, respectively. Three weeks before H1, the subjects underwent one control experiment in normoxia (N; inspired oxygen fraction 20.9%) without any treatment. Serum α-tocopherol was significantly higher after treatment with antioxidants compared with placebo. Capillary Po2 declined during H without significant differences between antioxidants and placebo. Plasma peroxide levels were lower under antioxidant treatment but not affected by hypoxia. The response of Epo to H did not show significant differences between antioxidant [maximum increase (means, 95% confidence interval): +121%, +66 to +176%] and placebo conditions (+108%, +68 to +149%). Similarly, hypoxia-induced increase of Epo corrected for diurnal variations, as revealed during N, did not differ between antioxidants and placebo. Individual variability of Epo in response to H was not related to the individual degree of hypoxemia during H. Our results do not support the assumption that ROS play a major modulating role in the response of Epo to short-term normobaric hypoxia in humans.
Mediastinal and chest wall limitations to asymmetry of lung inflation
Authors: Lin Ken C. , Dizner-Golab Anna , Thurer Robert L. , Loring Stephen H.
Published: February 2004

The extent to which inflation of one lung increases pleural pressure around the contralateral lung could affect ventilatory function, e.g., after pneumonectomy or lung transplantation. The rise in contralateral pleural pressure is limited by mediastinal stiffness and other chest wall properties. To estimate these properties, we determined an elastance of asymmetric expansion (EAsym) in 20 supine adults undergoing thoracic surgery requiring endobronchial intubation. Esophageal pressure, measured with a balloon catheter, was used as an estimate of pleural pressure for determining chest wall elastance during symmetric inflation. Pressures measured in the left and right lung airways during sequential asymmetric inflations with known volumes were used to calculate EAsymand elastances of left and right lungs by using a four-element mathematical model. Elastances (means ± SD) were 13.0 ± 8.7 (EAsym), 14.0 ± 7.0 (left lung), 12.2 ± 6.1 (right lung), and 6.7 ± 2.1 cmH2O/l (chest wall). EAsymwas high in three patients with prior cardiac surgery or mediastinal radiation therapy, suggesting that mediastinal stiffening due to scarring and fibrosis reduced pressure transmission between hemithoraxes. Simulations with a previously published model showed that changes in EAsymin the range of values observed could substantially affect lung ventilation after single-lung transplantation for emphysema.