bluuebunny/crossref_metadata_2025 huggingface dataset:
Variability in preterm lamb lung mechanics after intra-amniotic endotoxin is associated with changes in surfactant pool size and morphometry
Authors: Pillow J. Jane , Jobe Alan H. , Collins Rachel A. , Hantos Zoltán , Ikegami Machiko , Moss Timothy J. M. , Newnham John P. , Willet Karen E. , Sly Peter D.
Published: July 2004

Antenatal exposure to intra-amniotic (IA) endotoxin initiates a complex series of events, including an inflammatory cascade, increased surfactant production, and alterations to lung structure. Using the low frequency forced oscillation technique as a sensitive tool for measurement of respiratory impedance, we aimed to determine which factors contributed most to measured changes in lung mechanics. Respiratory impedance data obtained from sedated preterm lambs exposed to either IA injection with saline or 20 mg of endotoxin 1, 2, 4, and 15 days before delivery at 125 days gestation were studied, and association with indexes of standard lung morphometry, inflammatory response, and alveolar surfactant-saturated phosphatidylcholine (Sat PC) pool size was demonstrated. Reduction in tissue impedance with increasing interval between exposure and delivery was evident as early as 4 days after IA endotoxin injection, coinciding with resolution of inflammatory reaction, increased alveolar surfactant pools, and contribution of alveolar ducts to the parenchymal fraction, and a later decrease in the tissue component of the parenchymal fraction. Decreases in tissue damping (resistance) were more marked than decreases in tissue elastance. Log alveolar Sat PC accounted for most variability in tissue damping (88.9%) and tissue elastance (73.4%), whereas tissue fraction contributed 2 and 6.4%, respectively. The alveolar Sat PC pool size was the sole factor contributing to change in tissue hysteresivity. No changes were observed in airway resistance. Despite the complex cascade of events initiated by antenatal endotoxin exposure, variability in lung tissue mechanics is associated primarily with changes in alveolar Sat PC pool and lung morphology.
Prostasin, a membrane-anchored serine peptidase, regulates sodium currents in JME/CF15 cells, a cystic fibrosis airway epithelial cell line
Authors: Tong Zhenyue , Illek Beate , Bhagwandin Vikash J. , Verghese George M. , Caughey George H.
Published: July 2004

Prostasin is a tryptic peptidase expressed in prostate, kidney, lung, and airway. Mammalian prostasins are related to Xenopus channel-activating protease, which stimulates epithelial Na+channel (ENaC) activity in frogs. In human epithelia, prostasin is one of several membrane peptidases proposed to regulate ENaC. This study tests the hypothesis that prostasin can regulate ENaC in cystic fibrosis epithelia in which excessive Na+uptake contributes to salt and water imbalance. We show that prostasin mRNA and protein are strongly expressed by human airway epithelial cell lines, including immortalized JME/CF15 nasal epithelial cells homozygous for the ΔF508 cystic fibrosis mutation. Epithelial cells transfected with vectors encoding recombinant soluble prostasin secrete active, tryptic peptidase that is highly sensitive to inactivation by aprotinin. When studied as monolayers in Ussing chambers, JME/CF15 cells exhibit amiloride-sensitive, transepithelial Na+currents that are markedly diminished by aprotinin, suggesting regulation by serine-class peptidases. Overproduction of membrane-anchored prostasin in transfected JME/CF15 cells does not augment Na+currents, and trypsin-induced increases are small, suggesting that baseline serine peptidase-dependent ENaC activation is maximal in these cells. To probe prostasin’s involvement in basal ENaC activity, we silenced expression of prostasin using short interfering RNA targeting of prostasin mRNA’s 3′-untranslated region. This drops ENaC currents to 26 ± 9% of baseline. These data predict that prostasin is a major regulator of ENaC-mediated Na+current in ΔF508 cystic fibrosis epithelia and suggest that airway prostasin is a target for therapeutic inhibition to normalize ion current in cystic fibrosis airway.
Accessory cell function of airway epithelial cells
Authors: Oei Erwin , Kalb Thomas , Beuria Prarthana , Allez Matthieu , Nakazawa Atsushi , Azuma Miyuki , Timony Michael , Stuart Zanetta , Chen Houchu , Sperber Kirk
Published: July 2004

Oei, Erwin, Thomas Kalb, Prarthana Beuria, Matthieu Allez, Atsushi Nakazawa, Miyuki Azuma, Michael Timony, Zanetta Stuart, Houchu Chen, and Kirk Sperber. Accessory cell function of airway epithelial cells.

We previously demonstrated that airway epithelial cells (AECs) have many features of accessory cells, including expression of class II molecules CD80 and CD86 and functional Fcγ receptors. We have extended these studies to show that freshly isolated AECs have mRNA for cathepsins S, V, and H [proteases important in antigen (Ag) presentation], invariant chain, human leukocyte antigen (HLA)-DM-α and HLA-DM-β, and CLIP, an invariant chain breakdown product. A physiologically relevant Ag, ragweed, was colocalized with HLA-DR in AECs, and its uptake was increased by granulocyte-macrophage colony-stimulating factor and IFN-γ treatments, which had no effect on CD80 and CD86 expression. We demonstrate the presence of other costimulatory molecules, including B7h and B7-H1, on AECs and the increased expression of B7-H1 on AECs after treatment with granulocyte-macrophage colony-stimulating factor and IFN-γ. Finally, we compared T cell proliferation after allostimulation with AECs and dendritic cells (DCs). The precursor frequency of peripheral blood T cells responding to AECs was 0.264% compared with 0.55% for DCs. DCs stimulated CD45RO+, CD45RA+, CCR7+and CCR7−CD4+, and CD8+T cells, whereas AECs stimulated only CD45RO+, CD45RA−, CCR7−, CD4+, and CD8+T cells. There was no difference in cytokine production, type of memory T cells stimulated (effector vs. long-term memory), or apoptosis by T cells cocultured with AECs and DCs. The localization of AECs exposed to the external environment may make them important in the regulation of local immune responses.
Biological significance of nitric oxide-mediated protein modifications
Authors: Gow Andrew J. , Farkouh Christiana R. , Munson David A. , Posencheg Michael A. , Ischiropoulos Harry
Published: July 2004

Nitric oxide (NO), despite an apparently simple diatomic structure, has a wide variety of functions in both physiology and pathology and within every major organ system. It has become an increasingly important scientific challenge to decipher how this wide range of activity is achieved. To this end a number of investigators have begun to explore how NO-mediated posttranslational modifications of proteins may represent mechanisms of cellular signaling. These modifications include: 1) binding to metal centers; 2) nitrosylation of thiol and amine groups; 3) nitration of tyrosine, tryptophan, amine, carboxylic acid, and phenylalanine groups; and 4) oxidation of thiols (both cysteine and methionine residues) and tyrosine. However, two particular modifications have recently received much attention, nitrosylation of thiols to produce S-nitrosothiol and nitration of tyrosine residues to produce nitrotyrosine. It is the purpose of this review to examine the possibility that these modifications may play a role in NO-mediated signaling.
CFTR involvement in nasal potential differences in mice and pigs studied using a thiazolidinone CFTR inhibitor
Authors: Salinas Danieli B. , Pedemonte Nicoletta , Muanprasat Chatchai , Finkbeiner Walter F. , Nielson Dennis W. , Verkman A. S.
Published: July 2004

Nasal potential difference (PD) measurements have been used to demonstrate defective CFTR function in cystic fibrosis (CF) and to evaluate potential CF therapies. We used the selective thiazolidinone CFTR inhibitor CFTRinh-172 to define the involvement of CFTR in nasal PD changes in mice and pigs. In normal mice infused intranasally with a physiological saline solution containing amiloride, nasal PD was −4.7 ± 0.7 mV, hyperpolarizing by 15 ± 1 mV after a low-Cl−solution, and a further 3.9 ± 0.5 mV after forskolin. CFTRinh-172 produced 1.1 ± 0.9- and 4.3 ± 0.7-mV depolarizations when added after low Cl−and forskolin, respectively. Systemically administered CFTRinh-172 reduced the forskolin-induced hyperpolarization from 4.7 ± 0.4 to 0.9 ± 0.1 mV but did not reduce the low Cl−-induced hyperpolarization. Nasal PD was −12 ± 1 mV in CF mice after amiloride, changing by <0.5 mV after low Cl−or forskolin. In pigs, nasal PD was −14 ± 3 mV after amiloride, hyperpolarizing by 13 ± 2 mV after low Cl−and a further 9 ± 1 mV after forskolin. CFTRinh-172 and glibenclamide did not affect nasal PD in pigs. Our results suggest that cAMP-dependent nasal PDs in mice primarily involve CFTR-mediated Cl−conductance, whereas cAMP-independent PDs are produced by a different, but CFTR-dependent, Cl−channel. In pigs, CFTR may not be responsible for Cl−channel-dependent nasal PDs. These results have important implications for interpreting nasal PDs in terms of CFTR function in animal models of CFTR activation and inhibition.
Role of Cftr genotype in the response to chronic Pseudomonas aeruginosa lung infection in mice
Authors: van Heeckeren Anna M. , Schluchter Mark D. , Drumm Mitchell L. , Davis Pamela B.
Published: July 2004

Patients with cystic fibrosis have a lesion in the cystic fibrosis transmembrane conductance regulator gene (CFTR), which is associated with abnormal regulation of other ion channels, abnormal glycosylation of secreted and cell surface molecules, and vulnerability to bacterial infection and inflammation in the lung usually leading to the death of these patients. The exact mechanism(s) by which mutation in CFTR leads to lung infection and inflammation is not clear. Mice bearing different mutations in the murine homolog to CFTR ( Cftr) (R117H, S489X, Y122X, and ΔF508, all backcrossed to the C57BL/6J background) were compared with respect to growth and in their ability to respond to lung infection elicited with Pseudomonas aeruginosa-laden agarose beads. Body weights of mice bearing mutations in Cftr were significantly smaller than wild-type mice at most ages. The inflammatory responses to P. aeruginosa-laden agarose beads were comparable in mice of all four Cftr mutant genotypes with respect to absolute and relative cell counts in bronchoalveolar lavage fluid, and cytokine levels (TNF-α, IL-1β, IL-6, macrophage inflammatory protein-2, and keratinocyte chemoattractant) and eicosanoid levels (PGE2 and LTB4) in epithelial lining fluid: the few small differences observed occurred only between cystic fibrosis mice bearing the S489X mutation and those bearing the knockout mutation Y122X. Thus we cannot implicate either misprocessing of CFTR or failure of CFTR to reach the plasma membrane in the genesis of the excess inflammatory response of CF mice. Therefore, it appears that any functional defect in CFTR produces comparable inflammatory responses to lung infections with P. aeruginosa.
Actions of PPARγ agonism on adipose tissue remodeling, insulin sensitivity, and lipemia in absence of glucocorticoids
Authors: Berthiaume Magalie , Sell Henrike , Lalonde Josée , Gélinas Yves , Tchernof André , Richard Denis , Deshaies Yves
Published: July 2004

Peroxisome proliferator-activated receptor γ (PPARγ) agonists improve insulin sensitivity and lipemia partly through enhancing adipose tissue proliferation and capacity for lipid retention. The agonists also reduce local adipose glucocorticoid production, which may in turn contribute to their metabolic actions. This study assessed the effects of a PPARγ agonist in the absence of glucocorticoids (adrenalectomy, ADX). Intact, ADX, and intact pair-fed (PF) rats were treated with the PPARγ agonist rosiglitazone (RSG) for 2 wk. RSG increased inguinal (subcutaneous) white (50%) and brown adipose tissue (6-fold) weight but not that of retroperitoneal (visceral) white adipose tissue. ADX but not PF reduced fat accretion in both inguinal and retroperitoneal adipose depots but did not affect brown adipose mass. RSG no longer increased inguinal weight in ADX and PF rats but increased brown adipose mass, albeit less so than in intact rats. RSG increased cell proliferation in white (3-fold) and brown adipose tissue (6-fold), as assessed microscopically and by total DNA, an effect that was attenuated but not abrogated by ADX. RSG reduced the expression of the glucocorticoid-activating enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in all adipose depots. RSG improved insulin sensitivity (reduction in fasting insulin and homeostasis model assessment of insulin resistance, both −50%) and triacylglycerolemia (−75%) regardless of the glucocorticoid status, these effects being fully additive to those of ADX and PF. In conclusion, RSG partially retained its ability to induce white and brown adipose cell proliferation and brown adipose fat accretion and further improved insulin sensitivity and lipemia in ADX rats, such effects being therefore independent from the PPARγ-mediated modulation of glucocorticoids.
Role of estrogen in nitric oxide- and prostaglandin-dependent modulation of vascular conductance during treadmill locomotion in rats
Authors: Rogers Jennifer , Sheriff Don D.
Published: July 2004

Endothelial production of nitric oxide (NO) and prostaglandins (PG) may be greater in females than in males, increasing vasodilatory responses in females. Does sex influence the cardiovascular responses to dynamic exercise through estrogen-dependent modulation of NO and PG vasodilatory pathways? After the administration of hexamethonium, we assessed terminal aortic blood flow (TAQ), mean arterial pressure (MAP), and hindlimb vascular conductance (VC) in four groups of rats (6 males, 5 females, 5 ovariectomized females, and 6 ovariectomized females with chronic estrogen supplementation) during graded mild-intensity treadmill locomotion (5–15 m/min, 0° grade, 2 min). All rats repeated exercise after cyclooxygenase inhibition (indomethacin) and then again after NO synthase inhibition (nitro-l-arginine methyl ester) to examine the roles of NO and PG. Regression analysis was used to determine the influence of sex and plasma 17β-estradiol on TAQ, MAP, and VC. The analysis revealed that female sex did not influence TAQ but reduced MAP and increased VC at rest and during exercise conditions. Plasma 17β-estradiol (measured by immunoassay) significantly decreased MAP and increased TAQ and VC, irrespective of sex. Cyclooxygenase inhibition eliminated the significant association between MAP and estrogen, suggesting that estrogenic modulation occurred through PG-dependent processes. In contrast, the significant influence of estrogen on TAQ and VC was eliminated after NO synthase inhibition. On the basis of the overall findings of this study, estrogen influenced the vascular responses to dynamic exercise through PG- and NO-dependent pathways, but this occurred independent of sex.
Inhibitory effects of hyperthermia on mechanisms involved in autoresuscitation from hypoxic apnea in mice: a model for thermal stress causing SIDS
Authors: Kahraman Levent , Thach Bradley T.
Published: July 2004

The physiological mechanisms that might be involved in an association between heat stress and sudden infant death syndrome (SIDS) are obscure. We tested the hypothesis that a combination of acute hypoxia and elevated body temperature (TB) might prevent autoresuscitation from hypoxic apnea (AR). We exposed 21-day-old mice (total = 216) to hyperthermia (40.5–43.5°C), hypoxia, or a combination of the two. Neither hyperthermia alone (40.5–42.5°C) nor hypoxia alone was found to be lethal, but the combination produced failure to AR during the first hypoxic exposure with increasing frequency as TB increased. The ability to withstand multiple hypoxic exposures was also reduced as TB increased. In contrast, heat stress causing moderate TB increase (40.5°C) had no effect on survival. Increased TB (43.5°C) reduced gasping duration and number of gasps. It increased heart rate during anoxia but did not alter gasping rate. Furthermore, the oxygen-independent increase in heart rate observed before gasping failure was usually delayed until after the last gasp in hyperthermic animals. Mild dehydration occurred during TB elevation, but this did not appear to be a primary factor in AR failure. We conclude that a thermal stress, which by itself is nonlethal, frequently prevents AR from hypoxic apnea. This may be due, at least in part, to decreased gasp number and duration as well as to hyperthermia-related asynchrony of reflexes regulating heart and gasping frequencies during attempted AR.
Airway area distribution from the forced expiration maneuver
Authors: Lambert Rodney K. , Beck Kenneth C.
Published: July 2004

The maximal expiratory flow-volume (MEFV) maneuver is a commonly used test of lung function. More detailed interpretation than is currently available might be useful to understand disease better. We propose that a previously published computational model (Lambert RK, Wilson TA, Hyatt RE, and Rodarte JR. J Appl Physiol 52: 44–56, 1982) can be used to deduce, from the MEFV curve, the serial distribution of airway areas in the larger airways. An automated procedure based on the simulated annealing technique was developed. It was tested with model-generated flow data in which airway areas were reduced one generation at a time. The procedure accurately located the constriction and predicted its size within narrow bounds when the constriction was in the six most central generations of airways. More peripheral constrictions were detected but were not precisely located, nor were their sizes accurately evaluated. Airway areas of generations upstream of the constriction were usually overestimated. The procedure was applied to spirometric data obtained from eight volunteers (4 asthmatic and 4 normal subjects) at baseline and after methacholine challenge. The predicted areas show individual differences both in absolute values, and in relative distribution of areas. This result shows that detailed information can be obtained from the MEFV curve through the use of a model. However, this initial model, which lacks airway smooth muscle, needs further refinement.
Acetazolamide prevents hypoxic pulmonary vasoconstriction in conscious dogs
Authors: Höhne Claudia , Krebs Martin O. , Seiferheld Manuela , Boemke Willehad , Kaczmarczyk Gabriele , Swenson Erik R.
Published: July 2004

Acute hypoxia increases pulmonary arterial pressure and vascular resistance. Previous studies in isolated smooth muscle and perfused lungs have shown that carbonic anhydrase (CA) inhibition reduces the speed and magnitude of hypoxic pulmonary vasoconstriction (HPV). We studied whether CA inhibition by acetazolamide (Acz) is able to prevent HPV in the unanesthetized animal. Ten chronically tracheotomized, conscious dogs were investigated in three protocols. In all protocols, the dogs breathed 21% O2for the first hour and then 8 or 10% O2for the next 4 h spontaneously via a ventilator circuit. The protocols were as follows: protocol 1: controls given no Acz, inspired O2fraction (FiO2) = 0.10; protocol 2: Acz infused intravenously (250-mg bolus, followed by 167 μg·kg−1·min−1continuously), FiO2= 0.10; protocol 3: Acz given as above, but with FiO2reduced to 0.08 to match the arterial Po2(PaO2) observed during hypoxia in controls. PaO2was 37 Torr during hypoxia in controls, mean pulmonary arterial pressure increased from 17 ± 1 to 23 ± 1 mmHg, and pulmonary vascular resistance increased from 464 ± 26 to 679 ± 40 dyn·s−1·cm−5( P < 0.05). In both Acz groups, mean pulmonary arterial pressure was 15 ± 1 mmHg, and pulmonary vascular resistance ranged between 420 and 440 dyn·s−1·cm−5. These values did not change during hypoxia. In dogs given Acz at 10% O2, the arterial PaO2was 50 Torr owing to hyperventilation, whereas in those breathing 8% O2the PaO2was 37 Torr, equivalent to controls. In conclusion, Acz prevents HPV in conscious spontaneously breathing dogs. The effect is not due to Acz-induced hyperventilation and higher alveolar Po2, nor to changes in plasma endothelin-1, angiotensin-II, or potassium, and HPV suppression occurs despite the systemic acidosis with CA inhibition.
Age-dependent cerebral hemodynamic effects of indomethacin in the newborn piglet
Authors: Brown Derek W. , Lee David , Kumaran Vazhkudai S. , Lee Ting-Yim
Published: July 2004

With recent discussions in the literature regarding prophylactic use of early (within the first 12 h after birth), low-dose indomethacin to reduce the incidence and severity of intraventricular hemorrhage, knowledge pertaining to the cerebral hemodynamic effects of indomethacin in this age group is of significant interest. The cerebral circulation is known to undergo significant changes during the first few days of postnatal life. In the present study, we have investigated the hypothesis that postnatal adaptive changes influence the cerebral hemodynamic response to indomethacin in an age-dependent manner. Near-infrared spectroscopy with indocyanine green was used to measure cerebral hemodynamics, cerebral metabolic rate of oxygen, and cerebral oxygen extraction fraction in 39 newborn piglets. Piglets were grouped by age and received either 0.2 mg/kg indomethacin (14 were <13 h of age and 12 were >13 h of age) or saline (8 were <13 h of age and 5 were >13 h of age) infusions. In a subgroup of indomethacin-treated piglets (9 less than and 7 greater than 13 h of age), Doppler flow ultrasound was used to diagnose and monitor the presence and persistence of patent ductus arteriosus. Age was a significant factor in the cerebral hemodynamic response to indomethacin with piglets <13 h of age exhibiting delayed increases in cerebral blood flow and cerebral blood volume at 150 min post-indomethacin infusion.
Quantitative determination of localized tissue oxygen concentration in vivo by two-photon excitation phosphorescence lifetime measurements
Authors: Mik Egbert G. , van Leeuwen Ton G. , Raat Nicolaas J. , Ince Can
Published: July 2004

This study describes the use of two-photon excitation phosphorescence lifetime measurements for quantitative oxygen determination in vivo. Doubling the excitation wavelength of Pd-porphyrin from visible light to the infrared allows for deeper tissue penetration and a more precise and confined selection of the excitation volume due to the nonlinear two-photon effect. By using a focused laser beam from a 1,064-nm Q-switched laser, providing 10-ns pulses of 10 mJ, albumin-bound Pd-porphyrin was effectively excited and oxygen-dependent decay of phosphorescence was observed. In vitro calibration of phosphorescence lifetime vs. oxygen tension was performed. The obtained calibration constants were kq= 356 Torr−1·s−1(quenching constant) and τ0= 550 μs (lifetime at zero-oxygen conditions) at 37°C. The phosphorescence intensity showed a squared dependency to the excitation intensity, typical for two-photon excitation. In vivo demonstration of two-photon excitation phosphorescence lifetime measurements is shown by step-wise Po2measurements through the cortex of rat kidney. It is concluded that quantitative oxygen measurements can be made, both in vitro and in vivo , using two-photon excitation oxygen-dependent quenching of phosphorescence. The use of two-photon excitation has the potential to lead to new applications of the phosphorescence lifetime technique, e.g., noninvasive oxygen scanning in tissue at high spatial resolution. To our knowledge, this is the first report in which two-photon excitation is used in the setting of oxygen-dependent quenching of phosphorescence lifetime measurements.
Serial Studies of Mouse Atherosclerosis by In Vivo Magnetic Resonance Imaging Detect Lesion Regression After Correction of Dyslipidemia
Authors: Trogan Eugene , Fayad Zahi A. , Itskovich Vitalii V. , Aguinaldo Juan-Gilberto S. , Mani Venkatesh , Fallon John T. , Chereshnev Igor , Fisher Edward A.
Published: July 2004

Objective—

We determined the effects of sustained normocholesterolemia on advanced mouse atherosclerosis and whether changes in plaque size and composition can be detected noninvasively by MRI.

Methods and Results—

Aortic arch segments containing advanced lesions from apolipoprotein E–deficient (apoE−/−) mice (total cholesterol 1281±97 mg/dL) were transplanted into syngeneic wild-type (WT; 111±11 mg/dL) or apoE−/− (702±74 mg/dL) recipient mice on chow diet. Mice underwent serial MRI at 3, 5, 7, and 9 weeks after transplantation. Compared with 3 weeks, correction of dyslipidemia in WT recipient mice resulted in a monotonic decrease (regression) in arterial wall volume, whereas in apoE−/− recipient mice, further plaque progression was noted (
P
<0.05). MRI and histological measurements were closely correlated (
R
=0.937). The lesional content of macrophages decreased >90% (
P
<0.001), and smooth muscle cells increased in the WT recipient mice. In vivo T
1
-, T
2
-, and proton density–weighted images of the mouse thoracic aorta differentiated intraplaque lipid and collagen.

Conclusions—

Plaque changes can be noninvasively monitored by serial in vivo MRI of a mouse regression model. Our ability to image the thoracic aorta and perform in vivo plaque characterization will further enhance atherosclerosis studies.
Minocycline Exerts Multiple Inhibitory Effects on Vascular Endothelial Growth Factor–Induced Smooth Muscle Cell Migration
Authors: Yao Jianhua S. , Chen Yongmei , Zhai Wenwu , Xu Kaiyan , Young William L. , Yang Guo-Yuan
Published: July 2004

Widely used tetracycline antibiotics affect many cellular functions relevant to human vascular disease including cell proliferation, migration, and matrix remodeling. We examined whether minocycline inhibited human aortic smooth muscle cell (HASMC) migration induced by vascular endothelial growth factor (VEGF).

After the establishment of an optimal dose, minocycline treated HASMC were exposed to VEGF. HASMC migration, matrix metalloproteinase (MMP)-2 and MMP-9 activities, mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K) phosphorylation were determined by smooth muscle cell (SMC) invasion assay, real-time polymerase chain reaction, zymograms, and Western blot analysis, respectively.

We demonstrated that VEGF and platelet-derived growth factor (PDGF)-induced SMC migration in a dose-dependent manner. MMP-9, but not MMP-2, mRNA was increased during VEGF stimulation. MMP-9 activity was increased from 1.5- to 2.5-fold in a dose-dependent manner (
P
<0.05). Both ERK1/2 and PI3K/AKt pathways were activated during VEGF-induced HASMCs migration. We then demonstrated that minocycline can inhibit VEGF-induced HASMC migration (
P
<0.05). The effects may be through the inhibition of MMP-9 mRNA transcription, protein activities and downregulation of ERK1/2 and PI3K/Akt pathway phosphorylation.

Our results indicated that minocycline exerts multiple effects on VEGF-induced SMC migration, including inhibition of MMP-9 mRNA transcription and protein activities and downregulating ERK1/2 and PI3K signal pathways, suggesting minocycline may be a potentially therapeutic approach to inhibit disease process induced angiogenesis.
Chronic Hypoxia–Induced Upregulation of Store-Operated and Receptor-Operated Ca
2+
Channels in Pulmonary Arterial Smooth Muscle Cells
Authors: Lin Mo-Jun , Leung George P.H. , Zhang Wei-Min , Yang Xiao-Ru , Yip Kay-Pong , Tse Chung-Ming , Sham James S.K.
Published: July 2004

Chronic hypoxic pulmonary hypertension is associated with profound vascular remodeling and alterations in Ca
2+
homeostasis in pulmonary arterial smooth muscle cells (PASMCs). Recent studies show that transient receptor potential (TRPC) genes, which encode store-operated and receptor-operated cation channels, play important roles in Ca
2+
regulation and cell proliferation. However, the influence of chronic hypoxia on TRPC channels has not been determined. Here we compared TRPC expression, and store- and receptor-operated Ca
2+
entries in PASMCs of normoxic and chronic hypoxic rats. Reverse-transcription polymerase chain reaction (RT-PCR), Western blot, and immunostaining showed consistently that TRPC1, TRPC3, and TRPC6 were expressed in intralobar pulmonary arteries (PAs) and PASMCs. Application of 1-oleoyl-2-acetyl-sn-glycerol (OAG) to directly activate receptor-operated channels, or thapsigargin to deplete Ca
2+
stores, caused dramatic increase in cation entry measured by Mn
2+
quenching of fura-2 and by Ca
2+
transients. OAG-induced responses were ≈700-fold more resistant to La
3+
inhibition than thapsigargin-induced responses. siRNA knockdown of TRPC1 and TRPC6 specifically attenuated thapsigargin- and OAG-induced cation entries, respectively, indicating that TRPC1 mediates store-operated entry and TRPC6 mediates receptor-operated entry. In hypoxic PAs, there were 2- to 3-fold increases in TRPC1 and TRPC6 expression. They were accompanied by significant increases in basal, OAG-induced, and thapsigargin-induced cation entries in hypoxic PASMCs. Moreover, removal of Ca
2+
or inhibition of store-operated Ca
2+
entry with La
3+
and SK&F-96365 reversed the elevated basal [Ca
2+
]
i
in PASMCs and vascular tone in PAs of chronic hypoxic animals, but nifedipine had minimal effects. Our results for the first time to our knowledge show that both store- and receptor-operated channels of PASMCs are upregulated by chronic hypoxia and contribute to the enhanced vascular tone in hypoxic pulmonary hypertension.
Enhanced Postischemic Functional Recovery in CYP2J2 Transgenic Hearts Involves Mitochondrial ATP-Sensitive K
+
Channels and p42/p44 MAPK Pathway
Authors: Seubert John , Yang Baichun , Bradbury J. Alyce , Graves Joan , Degraff Laura M. , Gabel Scott , Gooch Rebecca , Foley Julie , Newman John , Mao Lan , Rockman Howard A. , Hammock Bruce D. , Murphy Elizabeth , Zeldin Darryl C.
Published: July 2004

Human CYP2J2 is abundant in heart and active in the biosynthesis of epoxyeicosatrienoic acids (EETs); however, the functional role of this P450 and its eicosanoid products in the heart remains unknown. Transgenic mice with cardiomyocyte-specific overexpression of CYP2J2 were generated. CYP2J2 transgenic (Tr) mice have normal heart anatomy and basal contractile function. CYP2J2 Tr hearts have improved recovery of left ventricular developed pressure (LVDP) compared with wild-type (WT) hearts after 20 minutes ischemia and 40 minutes reperfusion. Perfusion with the selective P450 epoxygenase inhibitor
N
-methylsulphonyl-6-(2-proparglyloxyphenyl)hexanamide (MS-PPOH) for 20 minutes before ischemia results in reduced postischemic LVDP recovery in WT hearts and abolishes the improved postischemic LVDP recovery in CYP2J2 Tr hearts. Perfusion with the ATP-sensitive K
+
channel (K
ATP
) inhibitor glibenclamide (GLIB) or the mitochondrial K
ATP
(mitoK
ATP
) inhibitor 5-hydroxydecanoate (5-HD) for 20 minutes before ischemia abolishes the cardioprotective effects of CYP2J2 overexpression. Flavoprotein fluorescence, a marker of mitoK
ATP
activity, is higher in cardiomyocytes from CYP2J2 Tr versus WT mice. Moreover, CYP2J2-derived EETs (1 to 5 μmol/L) increase flavoprotein fluorescence in WT cardiomyocytes. CYP2J2 Tr mice exhibit increased expression of phospho-p42/p44 mitogen-activated protein kinase (MAPK) after ischemia, and addition of the p42/p44 MAPK kinase (MEK) inhibitor PD98059 during reperfusion abolishes the cardioprotective effects of CYP2J2 overexpression. Together, these data suggest that CYP2J2-derived metabolites are cardioprotective after ischemia, and the mechanism for this cardioprotection involves activation of mitoK
ATP
and p42/p44 MAPK.
Long-Term Angiotensin-Converting Enzyme Inhibitor Perindopril Therapy Improves Cerebral Perfusion Reserve in Patients With Previous Minor Stroke
Authors: Hatazawa Jun , Shimosegawa Eku , Osaki Yasuhiro , Ibaraki Masanobu , Oku Naohiko , Hasegawa Shinji , Nagata Ken , Hirata Yutaka , Miura Yuko
Published: July 2004

Background and Purpose—

Angiotensin-converting enzyme (ACE) inhibitor-based therapy reduces the recurrence of stroke. The present study assessed the effects of long-term ACE inhibitor therapy on cerebral circulation in patients with previous minor stroke.

Methods—

After a run-in period, 19 patients were randomized to ACE inhibitor therapy (n=9; 4 mg of perindopril daily; mean age, 64±8 years; mean systolic/diastolic blood pressure [BP]±SD, 133±12/77±9 mm Hg) or placebo therapy (n=10; mean age, 66±9 years; mean BP, 139±10/78±8 mm Hg). Cerebral blood flow (CBF) was measured during hypercapnia, normocapnia, and hypocapnia using a positron emission tomography with H
2
15
O at entry into the study and after 3 to 12 months. Cerebral perfusion reserve (CPR) was defined as percent CBF response to a 1 mm Hg change in arterial partial pressure of CO
2
between hypercapnia and hypocapnia.

Results—

Systolic/diastolic BP and CBF during normocapnia showed no significant changes between entry and completion of the trial in the perindopril and placebo groups. Mean value of CPR showed a significant increase in the perindopril group (from 3.7±1.7%/mm Hg to 4.8±1.7%/mm Hg;
P
<0.05) but not in the placebo group (from 4.1±0.8%/mm Hg to 4.2±0.6%/mm Hg; NS). Statistical parametric mapping analysis also showed global and significant increase (
P
<0.01, uncorrected) in CPR in the perindopril group alone.

Conclusions—

Long-term ACE inhibitor-based therapy had a beneficial effect on the cerebral circulation by improving CPR in patients with previous minor stroke.
Gender Differences in the Relationship Between Periodontal Disease, Tooth Loss, and Atherosclerosis
Authors: Desvarieux Moïse , Schwahn Christian , Völzke Henry , Demmer Ryan T. , Lüdemann Jan , Kessler Christof , Jacobs David R. , John Ulrich , Kocher Thomas
Published: July 2004

Background and Purpose—

Males carry a disproportionate burden of cardiovascular disease. Because males also bear a higher burden of periodontal disease, we investigated the existence of gender differences in the postulated relationship between periodontal infections, tooth loss, and subclinical atherosclerosis.

Methods—

A total of 1710 randomly enrolled participants between the ages of 45 and 75 with no history of myocardial infarction or stroke received a clinical periodontal examination, carotid scan using high-resolution B-mode ultrasound, and extensive measurements for conventional cardiovascular risk factors (age, education, smoking, alcohol, body mass index, diabetes, systolic blood pressure, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides) as well as markers of healthy lifestyle and social network.

Results—

In both genders, measures of current and long-term periodontitis worsened as tooth loss increased. In males but not females, an ≈10% difference in carotid artery plaque prevalence was observed between the lowest and highest tertiles of tooth loss (
P
<0.05) and long-term periodontitis (
P
=0.05) after multivariate adjustment. Similar patterns were observed for intima–media thickness. The influence of gender on carotid artery plaque prevalence was most evident among the younger age group (<59 years). Between genders, carotid plaque prevalence differed by 10%, 15%, and 25% across increasing levels of tooth loss, and by 5%, 15%, and 25% across increasing levels of long-term periodontitis.

Conclusions—

Our data suggest that tooth loss and long-term periodontitis are related to subclinical atherosclerosis in men but not women. Gender variations in cardiovascular morbidity or mortality may be explained partly by the differential contributions of novel risk factors across genders.
Evidence That Estrogen Suppresses Rho-Kinase Function in the Cerebral Circulation In Vivo
Authors: Chrissobolis Sophocles , Budzyn Klaudia , Marley Philip D. , Sobey Christopher G.
Published: July 2004

Background and Purpose—

Premenopausal women are less susceptible to cardiovascular diseases than men or postmenopausal women. Such disease states are often associated with increased vascular RhoA/Rho-kinase activity and decreased activity of nitric oxide (NO). This study tested whether female gender is associated with lower Rho-kinase activity or higher NO activity in cerebral arteries in vivo and whether estrogen contributes to any such gender differences.

Methods—

Changes in basilar artery diameter were measured with the use of a cranial window preparation in anesthetized Sprague-Dawley rats. Some female rats were ovariectomized (OVX) and treated subcutaneously daily for 14 days with vehicle (dimethyl sulfoxide) or 17β-estradiol. Vascular expression of RhoA or Rho-kinase was assessed by Western blotting.

Results—

The Rho-kinase inhibitor Y-27632 was selectively ≈3-fold more potent as a cerebral vasodilator in males versus females. Expression of total RhoA or Rho-kinase did not differ between males and females. In OVX rats, vasodilator responses to Y-27632 resembled responses in males. Treatment of OVX rats with 17β-estradiol normalized the vasodilator effects of Y-27632 to be equivalent to responses in intact female controls. The NO synthase inhibitor
N
-nitro-
l
-arginine methyl ester caused ≈50% greater constriction of the basilar artery in females versus males, but responses in OVX rats treated with either vehicle or 17β-estradiol did not differ from those recorded in intact females.

Conclusions—

These data indicate that vascular Rho-kinase function is suppressed in females because of the effects of estrogen, whereas the higher NO activity in females is estrogen independent.
Mouse Model of Microembolic Stroke and Reperfusion
Authors: Atochin D.N. , Murciano J.C. , Gürsoy-Özdemir Y. , Krasik T. , Noda F. , Ayata C. , Dunn A.K. , Moskowitz M.A. , Huang P.L. , Muzykantov V.R.
Published: July 2004

Background and Purpose—

To test the role of fibrinolysis in stroke, we used a mouse model in which preformed 2.5- to 3-μm-diameter fibrin microemboli are injected into the cerebral circulation. The microemboli lodge in the downstream precapillary vasculature and are susceptible to fibrinolysis.

Methods—

We injected various doses of microemboli into the internal carotid artery in mice and characterized their distribution, effects on cerebral blood flow, neurological deficit, infarct area, and spontaneous dissolution. By comparing wild-type and tissue plasminogen activator (tPA) knockout (tPA
−/−
) mice, we analyzed the role of endogenous tPA in acute thrombotic stroke.

Results—

Microemboli cause dose-dependent brain injury. Although moderate doses of microemboli are followed by spontaneous reperfusion, they result in reproducible injury. Gene knockout of tPA markedly delays dissolution of cerebral emboli and restoration of blood flow and aggravates ischemic thrombotic infarction in the brain.

Conclusions—

We describe a microembolic model of stroke, in which degree of injury can be controlled by the dose of microemboli injected. Unlike vessel occlusion models, this model can be modulated to allow spontaneous fibrinolysis. Application to tPA
−/−
mice supports a key role of endogenous tPA in restoring cerebral blood flow and limiting infarct size after thrombosis.
No Evidence of Involvement of
Chlamydia pneumoniae
in Severe Cerebrovascular Atherosclerosis by Means of Quantitative Real-Time Polymerase Chain Reaction
Authors: Apfalter Petra , Barousch Wolfgang , Nehr Marion , Willinger Birgit , Rotter Manfred , Hirschl Alexander M.
Published: July 2004

Background and Purpose—

All studies reporting high numbers of
Chlamydia pneumoniae
DNA positives in stroke patients published to date have used polymerase chain reaction (PCR) techniques highly prone to generate false-positive results. The aim of this study was to analyze the prevalence of
C. pneumoniae
DNA in plaques of the carotid artery as well as in peripheral blood by means of a new, closed, real-time PCR system.

Methods—

Carotid endarterectomy specimens and preoperative peripheral blood mononuclear cells (PBMC) of 75 individuals with severe cerebrovascular atherosclerosis were analyzed by means of a
C. pneumoniae
-specific quantitative
omp
A-based real-time PCR TaqMan system. Plaques were also cultured onto HEp-2 cells. Before the surgical intervention,
C. pneumoniae
-specific IgM, IgG, and IgA as well as C-reactive protein (CRP) levels were determined.

Results—

89% of all patients studied had
C. pneumoniae-
specific antibodies, but the pathogen was not detected in a single carotid atheroma by real-time PCR and cell culture. However,
C. pneumoniae
DNA was detected in 4 PBMC samples (5.3%) at very low levels (<1 inclusion/6 mL EDTA blood). No statistical significance was found between symptomatic/asymptomatic patients,
C. pneumoniae
PCR, results and CRP values after correction for multiplicity-of-test adjustment.

Conclusions—

By means of a closed, highly sensitive, and specific real-time PCR,
C. pneumoniae
was not detected in cerebrovascular atherosclerosis. PCR on PBMC was not predictive for endovascular chlamydia infection and most likely stem from previous
C. pneumoniae
respiratory tract infection in individual cases.
Relationship Between Plasma Glutathione Levels and Cardiovascular Disease in a Defined Population
Authors: Shimizu Haruki , Kiyohara Yutaka , Kato Isao , Kitazono Takanari , Tanizaki Yumihiro , Kubo Michiaki , Ueno Hirofumi , Ibayashi Setsuro , Fujishima Masatoshi , Iida Mitsuo
Published: July 2004

Background and Purpose—

Glutathione (GSH) appears to have marked antioxidant activities and therefore may prevent cardiovascular disease (CVD). However, there are very few reports on this subject. In a community-based case–control study, we tested the hypothesis that low levels of plasma GSH are closely associated with CVD and its clinical types.

Methods—

The association between fasting plasma total GSH (tGSH) levels and CVD were assessed using conditional logistic regression analysis among 134 CVD cases and 435 age- and sex-matched healthy control subjects.

Results—

Mean tGSH concentrations were lower in all CVD cases than in the control subjects (3.06 versus 3.71 μmol/L;
P
=0.0001). Among the CVD types, both the cerebral infarction cases (2.98 versus 3.59 μmol/L;
P
=0.001) and cerebral hemorrhage cases (2.51 versus 3.43 μmol/L;
P
=0.0027) had significantly lower tGSH levels than the corresponding control groups had. The same tendency was observed for cases of subarachnoid hemorrhage (3.45 versus 3.83 μmol/L;
P
=0.36) and myocardial infarction (3.65 versus 3.77 μmol/L;
P
=0.69), but these differences were not statistically significant. After adjustment for other confounding factors, the risk of CVD was significantly lower in the third (adjusted odds ratio, 041; 95% CI, 0.21 to 0.77) and the fourth quartiles (adjusted odds ratio, 0.25; 95% CI, 0.12 to 0.51) than in the first. This association was most prominent in patients with lacunar infarction or cerebral hemorrhage.

Conclusions—

These findings suggest that reduced plasma tGSH levels are a risk factor for CVD, especially for cerebral small vessel disease.
Wine Production and Tourism
Authors: O’Neill Martin A. , Palmer Adrian
Published: July 2004

Tourism to the world’s wine-producing regions has grown rapidly in recent years, as travelers seek the opportunity to sample wineries’ products at the cellar door. The key to the continued growth and success of such enterprises lies in meeting customers’ expectations for service and products. One way to determine whether that is occurring is through an Importance Performance Analysis, which reveals how well an operation is performing on the attributes that are most important to guests. A study of wineries in Western Australia that used a modified SERVQUAL methodology found that operators are, on balance, performing well on the most important product and service attributes, based on a sample of 353 visitors to two wineries. The chief disconnect between the customers’ expectations and the wineries’ product was that the tourists expected a chance to taste the wineries’ premium products, but those vintages were not always available for tasting or incurred an additional charge.
Are Your Satisfied Customers Loyal?
Authors: Skogland Iselin , Siguaw Judy A.
Published: July 2004

The firmly held doctrine that guest satisfaction means repeat business is called into question by the results of this study of 364 guests of two similar big-city hotels. Analysis showed only a weak connection between satisfaction and loyalty (which is a precursor to repeat purchases). Examining such factors as purpose of travel and demographics, the study revealed another finding that may give hoteliers pause—especially considering the industry’s huge expenditures on frequent-guest programs. Business travelers were among the least loyal of the guests responding to this survey. The chief factors that engaged guests’ loyalty were hotel design and amenities. Moreover, the factor that caused guests to be most involved in the purchase decision (and therefore more interested in the hotel) was its employees. The implication is that hoteliers might consider redirecting some of their frequent-guest expenditures toward strengthening human resources and toward improving the guests’ experience through design and amenities.
The Relative Importance of Food, Atmosphere, and Fairness of Wait
Authors: Sulek Joanne M. , Hensley Rhonda L.
Published: July 2004

Food quality came out as the only one of nine factors being tested that had a significant effect on intent to return for 239 diners at an Irish-pub-style full-service restaurant in the southeastern United States. Even so, food provided only a partial explanation of the repeat-patronage decision. Examining customer satisfaction, food quality again was at the top of the list, but the restaurant’s atmosphere and the fairness of the seating procedures also had significant effects. Together, those three factors explained about half of the variability in a regression model of customer satisfaction. Given that food was such a strong factor in the repeat-patronage decision, diners’ suggestions to this restaurant are of interest to other restaurateurs. The diners suggested that the restaurant expand its menu. In particular, they wanted to see more items that fit the restaurant’s Irish-pub theme. Finally, diners were especially interested in having additional healthful menu items.
The Entrepreneurial Approach to Hotel Operation
Authors: Jogaratnam Giri , Tse Eliza Ching-Yick
Published: July 2004

Entrepreneurial hotels in Asia recorded better performance than their more-conservative competitors, according to a study of 164 hotels in mainland China and Hong Kong, Malaysia, and Singapore. The study defined an entrepreneurial approach as involving innovative, proactive, risk-taking actions. Entrepreneurial hotels were significantly more likely to be high performers, while conservative operations were more likely to be low performers. The entrepreneurial hotels were significantly more likely to agree with questionnaire statements that their operations were proactive, that they always seek new market opportunities, that they are the first to introduce new products, and that they constantly seek to improve their products. On the other hand, low-performing, conservative hotels were significantly more likely to agree that they are preempted by competitors and attempt to maintain the status quo rather than attempt risky new strategies. While this conclusion must be limited to the Asian hotels in the study, in the aggregate, entrepreneurial activity carried substantial rewards.