bluuebunny/crossref_metadata_2025 huggingface dataset:
Proinflammatory interleukin-1 cytokines increase mesangial cell hexokinase activity and hexokinase II isoform abundance
Authors: Taneja Navin , Coy Platina E. , Lee Iris , Bryson Jane M. , Robey R. Brooks
Published: April 2004

Mesangial cell hexokinase (HK) activity is increased by a diverse array of factors that share both an association with pathological conditions and a common requirement for classic MAPK pathway activation. To better understand the relationship between glucose (Glc) metabolism and injury and to indirectly test the hypothesis that these changes constitute a general adaptive response to insult, we have sought to identify and characterize injury-associated factors that couple to mesangial cell HK regulation. Proinflammatory interleukin-1 (IL-1) cytokines activate the MAPK pathway and have known salutary effects in this cell type. We therefore examined their ability to influence mesangial cell HK activity, Glc utilization, MAPK pathway activation, and individual HK isoform abundance. IL-1β increased HK activity in both a time- and concentration-dependent manner: activity increased maximally by ∼50% between 12 and 24 h with an apparent EC50 of 3 pM. IL-1α mimicked, but did not augment, the effects of IL-1β. Specific IL-1 receptor antagonism and selective MAPK/ERK kinase or upstream Ras inhibition prevented these increases, whereas PKC inhibition did not. Changes in HK activity were associated with both increased Glc metabolism and selective increases in HKII isoform abundance. We conclude that IL-1 cytokines can regulate cellular Glc phosphorylating capacity via an IL-1 receptor-, Ras-, and classic MAPK pathway-mediated increase in HKII abundance. These findings suggest a novel, previously undescribed mechanism whereby metabolism may be coupled to inflammation and injury.
Localized mechanical stress induces time-dependent actin cytoskeletal remodeling and stiffening in cultured airway smooth muscle cells
Authors: Deng Linhong , Fairbank Nigel J. , Fabry Ben , Smith Paul G. , Maksym Geoffrey N.
Published: April 2004

Mechanical stress (MS) causes cytoskeletal (CSK) and phenotypic changes in cells. Such changes in airway smooth muscle (ASM) cells might contribute to the pathophysiology of asthma. We have shown that periodic mechanical strain applied to cultured ASM cells alters the structure and expression of CSK proteins and increases cell stiffness and contractility (Smith PG, Moreno R, and Ikebe M. Am J Physiol Lung Cell Mol Physiol 272: L20–L27, 1997; and Smith PG, Deng L, Fredberg JJ, and Maksym GN. Am J Physiol Lung Cell Mol Physiol 285: L456–L463, 2003). However, the mechanically induced CSK changes, altered cell function, and their time courses are not well understood. Here we applied MS to the CSK by magnetically oscillating ferrimagnetic beads bound to the CSK. We quantified CSK remodeling by measuring actin accumulation at the sites of applied MS using fluorescence microscopy. We also measured CSK stiffness using optical magnetic twisting cytometry. We found that, during MS of up to 120 min, the percentage of beads associated with actin structures increased with time. At 60 min, 68.1 ± 1.6% of the beads were associated with actin structures compared with only 6.7 ± 2.8% before MS and 38.4 ± 5.5% in time-matched controls ( P < 0.05). Similarly, CSK stiffness increased more than twofold in response to the MS compared with time-matched controls. These changes were more pronounced than observed with contractile stimulation by 80 mM KCl or 10−4 M acetylcholine. Together, these findings imply that MS is a potent stimulus to enhance stiffness and contractility of ASM cells through CSK remodeling, which may have important implications in airway narrowing and dilation in asthma.
Interactions of exercise training and α-lipoic acid on insulin signaling in skeletal muscle of obese Zucker rats
Authors: Saengsirisuwan Vitoon , Perez Felipe R. , Sloniger Julie A. , Maier Thomas , Henriksen Erik J.
Published: April 2004

We have shown previously (Saengsirisuwan V, Kinnick TR, Schmit MB, and Henriksen EJ. J Appl Physiol 91: 145–153, 2001) that the antioxidant R-(+)-α-lipoic acid (R-ALA), combined with endurance exercise training (ET), increases glucose transport in insulin-resistant skeletal muscle in an additive fashion. The purpose of the present study was to investigate possible cellular mechanisms responsible for this interactive effect. We evaluated the effects of R-ALA alone, ET alone, or R-ALA and ET in combination on insulin-stimulated glucose transport, protein expression, and functionality of specific insulin-signaling factors in soleus muscle of obese Zucker ( fa/fa) rats. Obese animals remained sedentary, received R-ALA (30 mg·kg body wt−1·day−1), performed ET (daily treadmill running for ≤60 min), or underwent both R-ALA treatment and ET for 15 days. R-ALA or ET individually increased ( P < 0.05) insulin-mediated (5 mU/ml) glucose transport (2-deoxyglucose uptake) in soleus muscle by 45 and 68%, respectively, and this value was increased to the greatest extent (124%) in the combined treatment group. Soleus insulin receptor substrate (IRS)-1 protein was significantly increased by R-ALA alone (30%) or ET alone (31%), and a further enhancement (55%) was observed after the combination treatment in the obese animals. Enhanced levels of IRS-1 protein expression after individual or combined interventions were significantly correlated with insulin action on glucose transport activity ( r = 0.597, P = 0.0055). Similarly, insulin-mediated IRS-1 associated with the p85 regulatory subunit of phosphatidylinositol 3-kinase was increased by R-ALA (317%) and ET (319%) and to the greatest extent (435%) (all P < 0.05) by the combination treatment. These results indicate that the improvements of insulin action in insulin-resistant skeletal muscle after R-ALA or ET, alone and in combination, were associated with increases in IRS-1 protein expression and IRS-1 associated with p85.
Plasma hyperosmolality stimulates leptin secretion acutely by a vasopressin-adrenal mechanism
Authors: Levy James R. , Stevens Wayne
Published: April 2004

Glucose administration to rodents acutely stimulates leptin secretion. To investigate the mechanism, rats were infused intravenously with various concentrations of glucose, and plasma leptin concentrations were measured with time. The osmolality of the infusates was equalized with various concentrations of carbohydrates that are not metabolized. Hyperosmolar glucose stimulates leptin secretion in a dose-dependent manner, with peak plasma leptin concentrations occurring ∼3 h after the end of the glucose infusion. Hypertonic infusions of galactose, mannitol, and sodium chloride independently stimulate leptin secretion with approximately one-half the strength of equivalent osmolar concentrations of glucose. Peak plasma leptin concentrations occur ∼4 h after the end of the hypertonic solution infusion. Hypertonic solutions of mannitol do not stimulate leptin secretion in vasopressin-deficient or in adrenalectomized animals. In conclusion, intravenous infusions of hypertonic glucose and hypertonic mannitol independently stimulate leptin secretion. Hyperosmolality stimulates leptin secretion by a vasopressin-adrenal mechanism.
Lack of the intestinal Muc1 mucin impairs cholesterol uptake and absorption but not fatty acid uptake inMuc1−/−mice
Authors: Wang Helen H. , Afdhal Nezam H. , Gendler Sandra J. , Wang David Q.-H.
Published: April 2004

Before cholesterol and fatty acid molecules in the small intestinal lumen can interact with their possible transporters for uptake and absorption, they must pass through a diffusion barrier, which may modify the kinetics of nutrient assimilation. This barrier includes an unstirred water layer and a surface mucous coat, which is located at the intestinal lumen-membrane interface. In the present study, we investigated whether disruption of the mucin gene ( Muc) 1 may influence intestinal uptake and absorption of cholesterol and fatty acid in male Muc1−/−mice. The wild-type mice displayed relatively high levels of Muc1, Muc2, Muc3, and Muc4 mRNAs and relatively low levels of Muc5ac and Muc5b mRNAs in the small intestine. The absence of Muc1 mRNA and protein in the small intestines of Muc1−/−mice confirmed complete knockout of the Muc1 gene, but the mRNA expression for other mucin genes remained unchanged. Intestinal uptake and absorption of cholesterol but not palmitic acid were significantly reduced in Muc1−/−mice compared with the wild-type mice. However, knockout of the Muc1 gene did not impair either expression levels of the genes that encode intestinal sterol efflux transporters Abcg5 and Abcg8 and fatty acid transporter Fatp4 or small intestinal transit rates. We conclude that physiological levels of the epithelial mucin produced by the Muc1 gene are necessary for normal intestinal uptake and absorption of cholesterol in mice. Our study implies that because cholesterol absorption efficiency is reduced by ∼50% in Muc1-deficient mice, there may be one or more additional pathways for cholesterol absorption.
Differential regulation of Na+/H+exchange isoform activities by enteropathogenicE. coliin human intestinal epithelial cells
Authors: Hecht Gail , Hodges Kim , Gill Ravinder K. , Kear Fely , Tyagi Sangeeta , Malakooti Jaleh , Ramaswamy Krishnamurthy , Dudeja Pradeep K.
Published: April 2004

Enteropathogenic Escherichia coli (EPEC) is an important human intestinal foodborne pathogen associated with diarrhea, especially in infants and young children. Although EPEC produces characteristic attaching and effacing lesions and loss of microvilli, the pathophysiology of EPEC-associated diarrhea, particularly during early infection, remains elusive. The present studies were designed to examine the direct effects of EPEC infection on intestinal absorption via Na+/H+exchanger (NHE) isoforms. Caco-2 cells were infected with EPEC strain E2348/69 or nonpathogenic E. coli HB101 for a period of 60 to 120 min. Total NHE activity was significantly increased at 60 min, reaching approximately threefold increase after 90 min of EPEC infection. Similar findings were seen in HT-29 cells and T84 cells indicating that the response was not cell-line specific. Most surprising was the differential regulation of NHE2 and NHE3 by EPEC. Marked activation of NHE2 (300%) occurred, whereas significant inhibition (∼50%) of NHE3 activity was induced. The activity of basolateral isoform NHE1 was also significantly increased in response to EPEC infection. Mutations that disrupted the type III secretion system (TTSS) ablated the effect of EPEC on the activity of both NHE2 and NHE3. These results suggest that EPEC, through a TTSS-dependent mechanism, exerts differential effects on NHE isoform activity in intestinal epithelial cells. Additionally, NHEs do not appear to play any role in EPEC-mediated inflammation, because the NHE inhibitors amiloride and 5-( N-ethyl- N-isopropyl)amiloride did not prevent EPEC-mediated IκBα degradation.
Activation of IP prostanoid receptors prevents cardiomyocyte hypertrophy via cAMP-dependent signaling
Authors: Ritchie Rebecca H. , Rosenkranz A. C. , Huynh L. P. , Stephenson T. , Kaye D. M. , Dusting G. J.
Published: April 2004

The antihypertrophic action of angiotensin-converting enzyme inhibitors in the heart results partly from local potentiation of bradykinin. We have demonstrated that the antihypertrophic action of bradykinin is mediated by the release of nitric oxide from endothelium and elevation of cardiomyocyte cGMP. Whether other paracrine factors derived from the coronary endothelium, such as prostacyclin (PGI2), may act to prevent hypertrophy has not been explored. In the vasculature, activation by PGI2of IP and EP1prostanoid receptors elicits vasodilatation (via cAMP-dependent signaling) and vasoconstriction, respectively. The present objective was to determine whether IP prostanoid receptor activation has antihypertrophic actions in adult rat cardiomyocytes (ARCM). The selective IP agonist cicaprost (1 μM) virtually abolished the increase in [3H]phenylalanine incorporation (a marker of hypertrophy) induced either by endothelin-1 (ET-1; 60 nM, n = 10, P < 0.005) or by angiotensin II (1 μM, n = 6, P < 0.005). Cicaprost also inhibited ET-1 induction of c- fos mRNA expression, an additional marker of hypertrophy in ARCM ( n = 5, P < 0.005). In the absence of hypertrophic stimuli, cicaprost alone did not significantly influence either marker. The antihypertrophic actions of cicaprost were mimicked by the dual IP/EP1agonist iloprost (1 μM) in the presence of the EP1antagonist AH-6809 (3 μM). Furthermore, cicaprost modestly but significantly increased cardiomyocyte cAMP content by 13 ± 6% ( P < 0.05, n = 4), and the antihypertrophic effect of cicaprost was lost in the presence of the cAMP-dependent protein kinase inhibitor H-89 (1 μM, n = 5, P < 0.05). However, ET-1 also induced increases in the activity of the intracellular growth signals ERK1 (by 3-fold) and ERK2 (by 5-fold) in ARCM, and these were not inhibited by cicaprost ( P < 0.01, n = 5). Activation of IP receptors thus represents a novel approach to prevention of hypertrophy, and this effect is linked to cAMP-dependent signaling.
20-Hydroxyeicosatetraenoic acid is a vasoconstrictor in the newborn piglet pulmonary microcirculation
Authors: Fuloria Mamta , Eckman Delrae M. , Leach Daniel A. , Aschner Judy L.
Published: April 2004

20-Hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P-450 metabolite of arachidonic acid, is a vasoconstrictor in the systemic circulation and a vasodilator in the adult pulmonary circulation. Little is known about the vasoactive properties of 20-HETE in the newborn pulmonary circulation. The objectives of this study were to determine the vascular effects of 20-HETE and to explore the signaling mechanism(s) that mediate these effects in newborn pulmonary resistance-level arteries (PRA). Our findings demonstrate that, in contrast to the adult pulmonary circulation where 20-HETE mediates vasodilation, it causes constriction in newborn PRA at resting tone. Furthermore, inhibition of cyclooxygenase (COX) with indomethacin augments 20-HETE-induced constriction. The enhanced constrictor response to 20-HETE under conditions of COX inhibition is abolished in endothelium-disrupted PRA, suggesting that 20-HETE either stimulates endothelium-derived COX to release a counteracting vasodilator or is rapidly metabolized by COX to a less potent vasoconstrictor. 20-HETE-induced constriction is significantly inhibited by blocking calcium-dependent K+(KCa) channels and the thromboxane-PGH2receptor. Altogether, our data indicate that the vascular actions of 20-HETE are partially mediated via the activation of KCachannels and are significantly modulated by interactions with the COX-prostaglandin pathway.
Effects of metabolites and analogs of amiodarone on alveolar macrophages: structure-activity relationship
Authors: Quaglino Daniela , Ha Huy Riem , Duner Elena , Bruttomesso Daniela , Bigler Laurent , Follath Ferenc , Realdi Giuseppe , Pettenazzo Andrea , Baritussio Aldo
Published: April 2004

Amiodarone, an antiarrhythmic drug toxic toward the lung, is metabolized through sequential modifications of the diethylaminoethoxy group to mono- N-desethylamiodarone (MDEA), di- N-desethylamiodarone (DDEA), and amiodarone-EtOH (B2-O-EtOH), whose effects on lung cells are unclear. To clarify this, we exposed rabbit alveolar macrophages to analogs with different modifications of the diethylaminoethoxy group and then searched for biochemical signs of cell damage, formation of vacuoles and inclusion bodies, and interference with the degradation of surfactant protein A, used as a tracer of the endocytic pathway. The substances studied included MDEA, DDEA, and B2-O-EtOH, analogs with different modifications of the diethylaminoethoxy group, fragments of the amiodarone molecule, and the antiarrhythmic agents dronedarone (SR-33589) and KB-130015. We found the following: 1) MDEA, DDEA, and B2-O-EtOH rank in order of decreasing toxicity toward alveolar macrophages, indicating that dealkylation and deamination of the diethylaminoethoxy group represent important mechanisms of detoxification; 2) dronedarone has greater, and KB-130015 has smaller, toxicity than amiodarone toward alveolar macrophages; and 3) the benzofuran moiety, which is toxic to liver cells, is not directly toxic toward alveolar macrophages.
Identification and functional assessment of the novel murine organic anion transporter Oat5 (Slc22a19) expressed in kidney
Authors: Youngblood Geri L. , Sweet Douglas H.
Published: April 2004

An uncharacterized murine cDNA clone was identified and, through sequence, phylogenetic, and functional analysis, determined to encode the newest member of the organic anion transporter family, organic anion transporter 5 (Oat5; Slc22a19). The Oat5 cDNA clone contained an insert 1,964 bp in length with a predicted open reading frame (from bp 84 to bp 1,739) coding for a peptide 551 amino acids long. Slc22a19 was localized to mouse chromosome 19 near the genes encoding Oat1 ( Slc22a6) and Oat3 ( Slc22a8). Northern blot analysis revealed Oat5 is highly expressed in the kidney of adult mice and rats. No sexual dimorphism in renal or hepatic expression of Oat5 was observed. Unlike Oat1–3, Oat5 expression was not detected in the choroid plexus of either mice or rats. Murine Oat5-expressing Xenopus laevis oocytes supported increased accumulation of the mycotoxin ochratoxin A, compared with water-injected control oocytes. This uptake was significantly inhibited by probenecid and the organic anions 2,4-dichlorophenoxyacetic acid, salicylate, and estrone sulfate but not by para-aminohippurate or urate. Transport of ochratoxin A by murine Oat5 was saturable, with an estimated Kmof 2.0 ± 0.45 μM. Oat5-mediated transport was neither cis-inhibited nor trans-stimulated by the dicarboxylate glutarate. Uptake was also completely unaffected by short-circuiting of the membrane potential. Thus the motive forces behind Oat5 function, which provide insight into its membrane localization, need to be further resolved. These data demonstrate for the first time that this newly identified gene encodes a protein that functions as an organic anion transporter.
Extracellular ATP-induced calcium signaling in mIMCD-3 cells requires both P2X and P2Y purinoceptors
Authors: Xia Shen-Ling , Wang Lanjun , Cash Melanie N. , Teng Xueling , Schwalbe Ruth A. , Wingo Charles S.
Published: April 2004

Kidney tubules are targets for the activation of locally released nucleotides through multiple P2 receptor types. Activation of these P2 receptors modulates cellular Ca2+signaling and downstream cellular function. The purpose of this study was to determine whether P2 receptors were present in mIMCD-3 cells, a mouse inner medullary collecting duct cell line, and if so, to examine their link with intracellular Ca2+homeostasis. To monitor intracellular Ca2+concentration ([Ca2+]i), experiments were conducted using the fluorescent dye fura 2. ATP (0.1–100 μM) produced a dose-dependent increase in [Ca2+]iin a physiological Ca2+-containing solution, with an EC50of 2.5 μM. The P2-receptor antagonist PPADS reduced the effect of ATP on [Ca2+]i, and the P1-receptor agonist adenosine caused only a small increase in [Ca2+]i. Preincubation of cells with the phospholipase C antagonist U-73122 blocked the ATP-induced increase in [Ca2+]i, indicating P2Y receptors were involved in this process. In a Ca2+-free bath solution, thapsigargin and ATP induced intracellular Ca2+release from an identical pool. Nucleotides caused an increase in [Ca2+]iin the potency order of UTP = ATP > ATPγS > ADP > UDP that is best fitted with the P2Y2subtype profile. Although the P2Y agonist UTP induced a similar large transient increase in [Ca2+]ias did ATP, a small but sustained increase in [Ca2+]ioccurred only in ATP-stimulated cells, suggesting the role of P2X receptors in Ca2+influx. The sustained increase in [Ca2+]icould be blocked by either nonselective cation channel blockers Gd3+or P2X antagonists PPADS and PPNDS. Furthermore, when either Gd3+or PPNDS was applied to the bath solution before ATP application, the ATP-induced increase in [Ca2+]iwas significantly reduced. Both RT-PCR and Western blotting corroborated the presence of P2X1and P2Y2receptors. These studies demonstrate that mIMCD-3 cells have both P2X and P2Y subtype receptors and that the activation of both P2X and P2Y receptors by extracellular ATP appears to be required to regulate intracellular Ca2+signaling.
Vestibular activation does not influence skin sympathetic nerve responses during whole body heating
Authors: Wilson Thad E. , Kuipers Nathan T. , McHugh Erica A. , Ray Chester A.
Published: April 2004

The cutaneous vasculature and eccrine sweat glands are modified by both thermal and nonthermal factors. To determine the effect of thermal stress on the vestibulosympathetic reflex, skin sympathetic nerve activity (SSNA) and cutaneous end-organ responses were measured in 10 subjects during static head-down rotation (HDR) and dynamic yaw and pitch (30 cycles/min) to activate the otolith organs and semicircular canals. SSNA (microneurography of peroneal nerve), cutaneous vascular conductance (CVC; laser-Doppler flux/mean arterial pressure), sweat rate (capacitance hygrometry), and body temperature were collected during normothermia and after whole body heating. Body temperature was controlled by perfusing neutral (34–35°C) or warm (44–46°C) water through a tube-lined suit. During normothermia, HDR did not alter SSNA (−0.4 ± 4.4% change), CVC (4.2 ± 6.9% change), or sweat rate (−2.7 ± 1.2% change) within the innervated area of skin. Dynamic yaw and pitch also did not elicit significant changes in SSNA, CVC, or sweat rate during normothermia. Whole body heating significantly increased internal temperature (0.8 ± 0.1°C), mean skin temperature (4.1 ± 0.2°C), CVC (322 ± 109% control), and sweat rate (0.35 ± 0.08 mg·cm−2·min−1). After whole body heating, HDR did not significantly alter SSNA (3.2 ± 7.6% change), CVC (−7.3 ± 3.9% change), or sweat rate (−3.3 ± 1.9% change). Dynamic yaw and pitch also did not produce significant changes in SSNA, CVC, or sweat rate after whole body heating. These data suggest that vestibular activation by head movements is not a nonthermal factor affecting SSNA and cutaneous end-organ responses in humans.
Validity and reliability of dual-energy X-ray absorptiometry for the assessment of abdominal adiposity
Authors: Glickman Scott G. , Marn Charles S. , Supiano Mark A. , Dengel Donald R.
Published: April 2004

A number of methods exist for the estimation of abdominal obesity, ranging from waist-to-hip ratio to computed tomography (CT). Although dual-energy X-ray absorptiometry (DXA) was originally used to measure bone density and total body composition, recent improvements in software allow it to determine abdominal fat mass. Sixty-five men and women aged 18–72 yr participated in a series of studies to examine the validity and reliability of the DXA to accurately measure abdominal fat. Total body fat and abdominal regional fat were measured by DXA using a Lunar DPX-IQ. Multislice CT scans were performed between L1 and L4 vertebral bodies (region of interest) using a Picker PQ5000 CT scanner, and volumetric analyses were carried out on a Voxel Q workstation. Both abdominal total tissue mass ( P = 0.02) and abdominal fat mass ( P < 0.0001) in the L1–L4 region of interest were significantly lower as measured by DXA compared with multislice CT. However, Bland-Altman analysis demonstrated good concordance between DXA and CT for abdominal total tissue mass (i.e., limits of agreement = −1.56–2.54 kg) and fat mass (i.e., limits of agreement = −0.40–1.94 kg). DXA also showed excellent reliability among three different operators to determine total, fat, and lean body mass in the L1–L4 region of interest (intraclass correlations, R = 0.94, 0.97, and 0.89, respectively). In conclusion, the DXA L1–L4 region of interest compared with CT proved to be both reliable and accurate method to determine abdominal obesity.
Targeted viral delivery of Cre recombinase induces conditional gene deletion in cardiovascular circuits of the mouse brain
Authors: Sinnayah Puspha , Lindley Timothy E. , Staber Patrick D. , Davidson Beverly L. , Cassell Martin D. , Davisson Robin L.
Published: April 2004

The Cre/loxP system has shown promise for investigating genes involved in nervous system function and pathology, although its application for studying central neural regulation of cardiovascular function and disease has not been explored. Here, we report for the first time that recombination of loxP-flanked genes can be achieved in discrete cardiovascular regulatory nuclei of adult mouse brain using targeted delivery of adenovirus (Ad) or feline immunodeficiency virus (FIV) bearing Cre recombinase (Ad-Cre, FIV-Cre). Single stereotaxic microinjections of Ad-Cre or FIV-Cre into specific nuclei along the subfornical organ-hypothalamic-hypophysial and brain stem-parabrachial axes resulted in robust and highly localized gene deletion as early as 7 days and for as long as 3 wk in a reporter mouse model in which Cre recombinase activates β-galactosidase expression. An even greater selectivity in Cre-mediated gene deletion could be achieved in unique subpopulations of cells, such as vasopressin-synthesizing magnocellular neurons, by delivering Ad-Cre via retrograde transport. Moreover, Ad-Cre and FIV-Cre induced gene recombination in differential cell populations within these cardiovascular nuclei. FIV-Cre infection resulted in LacZ activation selectively in neurons, whereas both neuronal and glial cell types underwent gene recombination upon infection with Ad-Cre. These results establish the feasibility of using a combination of viral and Cre/loxP technologies to target specific cardiovascular nuclei in the brain for conditional gene modification and suggest the potential of this approach for determining the functional role of genes within these sites.
An integrated reverse functional genomic and metabolic approach to understanding orotic acid-induced fatty liver
Authors: Griffin Julian L. , Bonney Stephanie A. , Mann Chris , Hebbachi Abdul M. , Gibbons Geoff F. , Nicholson Jeremy K. , Shoulders Carol C. , Scott James
Published: April 2004

In functional genomics, DNA microarrays for gene expression profiling are increasingly being used to provide insights into biological function or pathology. To better understand the significance of the multiple transcriptional changes across a time period, the temporal changes in phenotype must be described. Orotic acid-induced fatty liver disease was investigated at the transcriptional and metabolic levels using microarrays and metabolic profiling in two strains of rats. High-resolution1H-NMR spectroscopic analysis of liver tissue indicated that Kyoto rats compared with Wistar rats are predisposed to the insult. Metabolite analysis and gene expression profiling following orotic acid treatment identified perturbed metabolic pathways, including those involved in fatty acid, triglyceride, and phospholipid synthesis, β-oxidation, altered nucleotide, methyl donor, and carbohydrate metabolism, and stress responses. Multivariate analysis and statistical bootstrapping were used to investigate co-responses with transcripts involved in metabolism and stress responses. This reverse functional genomic strategy highlighted the relationship between changes in the transcription of stearoyl-CoA desaturase 1 and those of other lipid-related transcripts with changes in NMR-derived lipid profiles. The results suggest that the integration of1H-NMR and gene expression data sets represents a robust method for identifying a focused line of research in a complex system.
DNA microarray analysis of gene expression in human optic nerve head astrocytes in response to hydrostatic pressure
Authors: Yang Ping , Agapova Olga , Parker Amy , Shannon William , Pecen Paula , Duncan Jill , Salvador-Silva Mercedes , Hernandez M. Rosario
Published: April 2004

There is clinical and experimental evidence that elevated intraocular pressure (IOP), a mechanical stress, is involved in the pathogenesis of glaucomatous optic neuropathy. The mechanism by which astrocytes in the optic nerve head (ONH) respond to changes in IOP is under study. Gene transcription by ONH astrocytes exposed either to 60 mmHg hydrostatic pressure (HP) or control ambient pressure (CP) for 6, 24, and 48 h was compared using Affymetrix GeneChip microarrays to identify HP-responsive genes. Data were normalized across arrays within each gene. A linear regression model applied to test effect of time and HP on changes in expression level identified 596 genes affected by HP over time. Using GeneSpring analysis we selected genes whose average expression level increased or decreased more than 1.5-fold at 6, 24, or 48 h. Expression of selected genes was confirmed by real-time RT-PCR; protein levels were detected by Western blot. Among the genes highly responsive to HP were those involved in signal transduction, such as Rho nucleotide exchange factors, Ras p21 protein activator, tyrosine kinases and serine threonine kinases, and genes involved in transcriptional regulation, such as c-Fos, Egr2, and Smad3. Other genes that increased expression included ATP-binding cassettes, solute carriers, and genes associated with lipid metabolism. Among the genes that decreased expression under HP were genes encoding for dual activity phosphatases, transcription factors, and enzymes involved in protein degradation. These HP-responsive genes may be important in the establishment and maintenance of the ONH astrocyte phenotype under conditions of elevated IOP in glaucoma.
Longitudinal transcriptional analysis of developing neointimal vascular occlusion and pulmonary hypertension in rats
Authors: Vaszar Laszlo T. , Nishimura Toshihiko , Storey John D. , Zhao Guohua , Qiu Daoming , Faul John L. , Pearl Ronald G. , Kao Peter N.
Published: April 2004

Pneumonectomized rats injected with the alkaloid toxin, monocrotaline, develop progressive neointimal pulmonary vascular obliteration and pulmonary hypertension resulting in right ventricular failure and death. The antiproliferative immunosuppressant, triptolide, attenuates neointimal formation and pulmonary hypertension in this disease model (Faul JL, Nishimura T, Berry GJ, Benson GV, Pearl RG, and Kao PN. Am J Respir Crit Care Med 162: 2252–2258, 2000). Pneumonectomized rats, injected with monocrotaline on day 7, were killed at days 14, 21, 28, and 35 for measurements of physiology and gene expression patterns. These data were compared with pneumonectomized, monocrotaline-injected animals that received triptolide from day 5 to day 35. The hypothesis was tested that a group of functionally related genes would be significantly coexpressed during the development of disease and downregulated in response to treatment. Transcriptional analysis using total lung RNA was performed on replicate animals for each experimental time point with exploratory data analysis followed by statistical significance analysis. Marked, statistically significant increases in proteases (particularly derived from mast cells) were noted that parallel the development of vascular obliteration and pulmonary hypertension. Mast-cell-derived proteases may play a role in regulating the development of neointimal pulmonary vascular occlusion and pulmonary hypertension in response to injury.
Trends in Incidence of Brain and Central Nervous System Tumors in Norway, 1970–1999
Authors: Johannesen T.B. , Angell-Andersen E. , Tretli S. , Langmark F. , Lote K.
Published: April 2004

The aim of this study was to investigate trends in the incidence of childhood and adult brain and central nervous system (CNS) tumors in Norway from 1970 through 1999. In this period, a total of 14,641 patients were diagnosed with a primary benign or malignant neoplasm of the brain and CNS. Age-adjusted incidence rates were reported together with results of loglinear regression and an age-period-cohort model based on the Poisson regression model. In children (<15 years), the proportion of brain and CNS tumors was 28.2% (1,042/3,697) of all new cancer cases compared with 2.8% in adults (13,599/492,237). The overall rate of brain and CNS tumors increased during the study period from 6.49 to 12.02 cases per 100,000 person-years. A trend of leveling off in incidence of most tumor categories during the study period was indicated with a possible continuing increase in the period 1995–1999, especially in the age group 0–4 years and in patients aged 60 years or more. Age and period together provided a satisfactory model in patients being <60 years of age and less completeness of diagnosis was found in males compared with females, possibly due to the distribution in males of more aggressive tumors.
The Confounding of Race and Geography: How Much of the Excess Stroke Mortality among African Americans Is Explained by Geography?
Authors: Yang Dongyan , Howard George , Coffey Christopher S. , Roseman Jeffrey
Published: April 2004

Introduction: The excess stroke mortality among African Americans and Southerners is well known. Because a higher proportion of the population living in the ‘Stroke Belt’ is African American, then a portion of the estimated excess risk of stroke death traditionally associated with African-American race may be attributable to geography (i.e., race and geography are ‘confounded’). In this paper we estimate the proportion of the excess stroke mortality among African Americans that is attributable to geography. Methods: The numbers of stroke deaths at the county level are available from the vital statistics system of the US. A total of 1,143 counties with a population of at least 500 whites and 500 African Americans were selected for these analyses. The black-to-white stroke mortality ratio was estimated with and without adjustment for county of residence for those aged 45–64 and for those aged 65 and over. The difference in the stroke mortality ratio before versus after adjustment for county provides an estimate of the proportion of the excess stroke mortality inappropriately attributed to race (that is in fact attributable to geographic region). Results: For ages 45–64, the black-to-white stroke mortality ratio was reduced from 3.41 to 3.04 for men, and from 2.82 to 2.60 for women, suggesting that between 10 and 15% of the excess mortality traditionally attributed to race is rather due to geography. Over the age of 65, the black-to-white stroke mortality ratio was reduced from 1.31 to 1.27 for men, and from 1.097 to 1.095 for women, suggesting that between 2 and 13% of the excess mortality attributed to black race is actually attributable to geography. The reductions of all the four age strata gender groups were highly significant. Discussion: These results suggest that a significant, although relatively small, proportion of the excess mortality traditionally attributed to race is rather a factor of geography.
Aspirin, NSAIDs, Risk of Dementia, and Influence of the Apolipoprotein E Epsilon 4 Allele in an Elderly Population
Authors: Cornelius C. , Fastbom J. , Winblad B. , Viitanen M.
Published: April 2004

In a cohort study, 1,301 subjects free of dementia at baseline in the Kungsholmen Project were followed up to 6 years. We studied the association between use of aspirin and non-steroidal anti-inflammatory drugs (NSAIDs), incidence of Alzheimer’s disease (AD) and overall dementia, and the influence of the apolipoprotein E Ε4 allele. In stratified analyses, a relative risk (RR) of 1.80 (95% CI 1.14–2.83) for AD was seen, in the apoE Ε4-negative group using aspirin. This implicates a possible different mechanism of developing AD in this group. We also found a possible protective effect of NSAIDs against AD, since no one who used NSAIDs for around 3 years had developed AD 3 years later. One user developed vascular dementia, and a low point value of risk was seen, however, not significant (RR 0.23; 95% CI 0.03–1.68). This could be due to the small samples in our study, or to comorbidity contributing to the development of dementia in this elderly population.
Review of Epidemiological Studies Searching for a Relationship between Onchocerciasis and Epilepsy
Authors: Druet-Cabanac M. , Boussinesq M. , Dongmo L. , Farnarier G. , Bouteille B. , Preux P.M.
Published: April 2004

A review and a meta-analysis of the available epidemiological literature for evidence of an association between onchocerciasis infection and epilepsy were carried out. We used EMBASE (1974–2002), MEDLINE (1966–2002), and PASCAL (1987–2002) databases and relevant journals and bibliographies. We limited our analysis to the epidemiological studies, where the status regarding onchocerciasis infection and epilepsy was available for each subject. Nine African studies were included. The common relative risk estimated by the random-effects model was 1.21 (95% CI 0.99–1.47; p = 0.06). The meta-analysis did not show any difference according to the onchocerciasis endemicity level and the African areas. Our results do not allow to conclude for an association between Onchocerca volvulus infection and epilepsy. However, the results are nearly significant. Further research is needed in this neglected subject, in particular for the better understanding of the neurological pathogenicity in onchocerciasis.
The Inhibition of Apoptosis in EL4 Lymphoma Cells Overexpressing Growth Hormone
Authors: Arnold Robyn E. , Weigent Douglas A.
Published: April 2004

The antiapoptotic action of exogenous growth hormone (GH) has been reported for several lymphoid cell lines; however, the potential role of endogenous GH in apoptosis has not been thoroughly investigated. This study was designed to investigate the effects of endogenous GH on apoptosis induced by methyl methanesulfonate (MMS) in a T cell lymphoma overexpressing GH (GHo). The results of these experiments have shown that in EL4 lymphoma cells, overexpression of GH sustained viability after exposure to MMS compared to control cells. The extent of DNA fragmentation measured by ladder formation on agarose gels was reduced in GHo cells following treatment with MMS, when compared to control cells. Adding exogenous GH to control cells and treatment of GHo cells with antibodies to GH had no effect on MMS-induced DNA ladder formation. In further studies, DNA microarray analysis suggested a marked decrease in the constitutive expression of bax, BAD, and caspases 3, 8, and 9 in GHo cells compared to controls. In addition, after treatment with MMS, the activities of caspases 2, 3, 6, 8, and 9 were all lower than control in GHo cells. Western blot analysis detected an increase in Bcl-2 while the levels of nuclear factor kappa B (NFĸB) remained unchanged in GHo cells. Treatment of EL4 cells with antisense deoxyoligonucleotides to GH and specific inhibitors of NFĸB (SN-50) increased DNA fragmentation. GHo cells show increased levels of phosphorylated Akt and GSK-3, suggesting inactivation of this proapoptotic protein. The results, taken together with our previous data which showed increased nitric oxide formation in GHo cells, suggest a possible mechanism for the antiapoptotic effects of endogenous GH through the production of nitric oxide and support the idea that endogenous GH may play an important role in the survival of lymphocytes exposed to stressful stimuli.
Beta Blocker and Angiotensin-Converting Enzyme Inhibitor Therapy Is Associated with Decreased Th1/Th2 Cytokine Ratios and Inflammatory Cytokine Production in Patients with Chronic Heart Failure
Authors: Gage Julia R. , Fonarow Gregg , Hamilton Michele , Widawski Mel , Martínez-Maza Otoniel , Vredevoe Donna L.
Published: April 2004

Objective: To examine the potential impact of β-blockers and angiotensin-converting enzyme (ACE) inhibitors, medications which modulate β-adrenergic signaling, on immune function in patients with chronic heart failure (HF). Methods: 118 patients attending an HF center were tested for circulating levels of norepinephrine (NE), T cells and the inflammation-associated cytokine interleukin 6 (IL-6). Levels of the cytokines interferon-γ (IFNγ), IL-10, and tumor necrosis factor-α (TNFα) produced by cultured peripheral blood mononuclear cells (PBMC) were measured in culture supernatants following T cell stimulation in vitro. Results: NE levels were significantly lower in patients receiving ACE inhibitors (p = 0.0263), with a trend toward lower NE in patients receiving β-blockers. All patients exhibited relatively normal levels of T cells, and there was a trend toward higher levels of total (CD3+) and helper (CD4+) T cells (p = 0.0578 and 0.0932, respectively) in patients receiving either type of medication. The ratios of Th1 (IFNγ) to Th2 (IL-10) cytokines were lower in patients receiving a combination of β-blocker and ACE inhibitor therapy (p = 0.0373). NYHA class was a significant predictor of serum IL-6 (p < 0.0001). There was a trend toward lower levels of serum IL-6 in patients receiving both types of medications (p = 0.0606). TNFα production by CD3/CD28-stimulated PBMC was significantly lower in patients receiving ACE inhibitor medications (p = 0.0223). Conclusions: These results suggest that high sympathetic tone associated with chronic HF affects Th1/Th2 and inflammatory cytokine production, and that these effects can be modulated by medications. In addition to improvement in clinical parameters relating to cardiovascular function, β-blocker and ACE inhibitor medications also appear to have a beneficial effect on the immune system in HF.
Effects of Amphetamine on Immune-Mediated Lung Inflammatory Response in Rats
Authors: Ligeiro-Oliveira A.P. , Fialho de Araújo A.M. , Lazzarini R. , Silva Z.L. , De Nucci G. , Muscará M.N. , Tavares de Lima W. , Palermo-Neto J.
Published: April 2004

Objective: The present study analyzed the effects of acute amphetamine (AMPH) treatment on immune-mediated lung inflammatory response in rats. Methods: There were four experiments. In the first and second experiments, rats were treated with AMPH (1 mg/kg) or 0.9% NaCl, and locomotor activity (experiment 1) and serum AMPH concentrations (experiment 2) were measured 1 or 12 h after treatment. In the third experiment, rats which were immunized with ovalbumin (OVA) were treated 14 days later with 0.9% NaCl or AMPH (1 mg/kg). Twelve hours after these treatments, all animals were submitted to challenge by 1% OVA inhalation being analyzed afterwards for bronchoalveolar lavage fluid (BAL), peripheral blood and bone marrow cellularity. In the fourth and final experiment, rats were treated and studied as for experiment 3, except that half of the animals within each group were previously treated with metyrapone prior to the OVA challenge. Results: In the non- immunized rats, AMPH treatment induced an increase in locomotor activity synchronized to high serum AMPH concentrations 1 h after, but not 12 h after treatment. In OVA-challenged rats, AMPH treatment decreased the total number of inflammatory cells, recovered in both BAL and peripheral blood and increased the total number of bone marrow cells. These effects, observed 1 day after OVA challenge, were abrogated by previous metyrapone treatment. Conclusion: AMPH treatment changed HPA-axis responsiveness to the stress condition imposed by the OVA challenge decreasing lung and blood leukocytes cellularity most probably via corticosterone actions on bone marrow activity.
Aktuelle Kontroverse der Hormonersatztherapie
Authors: Georges B. , Hermelink K. , Untch M. , Hepp H.
Published: April 2004

Vor 2 Jahren wurde in Amerika die Women’s Health Initiative (WHI)-Studie abgebrochen. Vor einem Jahr erschien die britische One-Million-Women-Studie und trug zusammen mit der WHI-Studie dazu bei, dass die Diskussion um die Hormonersatztherapie neu entfacht wurde. Seitdem wird in den Medien, unter Wissenschaftlern und Ärzten diskutiert und abgewogen. Von Einigkeit kann noch nicht gesprochen werden, allerdings haben die Deutsche Gesellschaft für Senologie und die Deutsche Gesellschaft für Gynäkologie und Geburtshilfe dazu klare Stellungnahmen abgegeben. Ein zentrales Thema der Diskussionen sind Zusammenhänge von Hormonsubstitution und Mammakarzinom. Aus In-vitro-Untersuchungen ist bekannt, dass Östrogene das Brustepithel stimulieren und dass eine verlängerte Östrogenexposition, z.B. durch frühe Menarche und späte Menopause, das Mammakarzinomrisiko erhöhen kann. Indikationen der Hormontherapie (seither als Hormonersatztherapie bekannt) sind bisher klimakterische Beschwerden, Osteoporoseprophylaxe, Verbesserung kognitiver Leistungsfähigkeit sowie Demenzprophylaxe. Diese Indikationen werden vor dem Hintergrund aktueller Studiendaten diskutiert.
Die Sentinellymphknoten-Entfernung beim Mammakarzinom: Derzeitiger Stand
Authors: Bauerfeind Ingo , Himsl Isabelle , Kühn Thorsten , Untch Michael , Hepp Hermann
Published: April 2004

Beim invasiven Mammakarzinom ist die axilläre Lymphonodektomie (ALN) der Level I und II mit der Entfernung von mindestens 10 Lymphknoten der operative Goldstandard. Die ALN dient als diagnostische Massnahme zur histopathologischen Tumorklassifikation, der Prognoseabschätzung, der lokoregionären Tumorkontrolle sowie zur adjuvanten Therapieentscheidung. Die Sentinellymphknoten-Entfernung (Sentinel-Node-Biopsie, SNB) stellt ein minimal-invasives Operationsverfahren dar, bei dem der Nodalstatus durch Entnahme von einem (oder mehreren) Wächterlymphknoten (Sentinellymphknoten) bestimmt werden kann. Die Methode setzt sich zunehmend in der klinischen Routine durch und ersetzt die konventionelle Axilladissektion bei Patientinnen mit frühem Mammakarzinom. Auf die klassische ALN sollte nur dann verzichtet werden, wenn in den Sentinellymphknoten sowohl in der Schnellschnitthistologie als auch in der endgültigen histopathologischen Untersuchung keine metastatische Infiltration nachgewiesen wird. Die Implementierung der SNB als operatives Standardverfahren sollte unter qualitätsgesicherten Bedingungen durchgeführt werden.
Lack of Evidence for the Association of E-Cadherin Gene Polymorphism with Increased Risk or Progression of Prostate Cancer
Authors: Tsukino Hiromasa , Kuroda Yoshiki , Imai Hirohisa , Nakao Hiroyuki , Qiu Delai , Komiya Yasuhiro , Inatomi Hisato , Hamasaki Takashi , Kohshi Kiyotaka , Osada Yukio , Katoh Takahiko
Published: April 2004

Background: E-cadherin is an epithelial cell adhesion molecule, and decreased E-cadherin expression in human prostate cancer is associated with tumor grade and advanced clinical stage. A –160 C→A polymorphism in the promoter region of E-cadherin has been shown to decrease gene transcription. This allelic variation may be a potential genetic marker that can help identify those individuals at higher risk for invasive/metastatic disease. Materials and Methods: We studied the effect of E-cadherin gene polymorphism on prostate cancer susceptibility in a case control study of 219 prostate cancer patients and 219 male controls, to determine whether this polymorphism is a biomarker for the risk and how aggressive the disease is. Results: The genotype frequencies in the prostate cancer group were C/C: 0.607, C/A: 0.352, A/A: 0.041, and in the control group C/C: 0.671, C/A: 0.301, A/A: 0.027. A significant difference between the two groups was not found (p = 0.34), and the adjusted OR for A/A genotype was not statistically significant (OR = 1.66, 95% CI 0.58–4.78). Subdividing prostate cancer according to tumor differentiation and stage, we found no association between E-cadherin polymorphism and poor differentiation and invasiveness of prostate cancer. Conclusions: These data do not support an association between the E-cadherin genotype and the occurrence or progression of prostate cancer in Japanese populations.