bluuebunny/crossref_metadata_2025 huggingface dataset:
Modulation of electron transport protects cardiac mitochondria and decreases myocardial injury during ischemia and reperfusion
Authors: Chen Qun , Camara Amadou K. S. , Stowe David F. , Hoppel Charles L. , Lesnefsky Edward J.
Published: September 2006

Mitochondria are increasingly recognized as lynchpins in the evolution of cardiac injury during ischemia and reperfusion. This review addresses the emerging concept that modulation of mitochondrial respiration during and immediately following an episode of ischemia can attenuate the extent of myocardial injury. The blockade of electron transport and the partial uncoupling of respiration are two mechanisms whereby manipulation of mitochondrial metabolism during ischemia decreases cardiac injury. Although protection by inhibition of electron transport or uncoupling of respiration initially appears to be counterintuitive, the continuation of mitochondrial oxidative phosphorylation in the pathological milieu of ischemia generates reactive oxygen species, mitochondrial calcium overload, and the release of cytochrome c. The initial target of these deleterious mitochondrial-driven processes is the mitochondria themselves. Consequences to the cardiomyocyte, in turn, include oxidative damage, the onset of mitochondrial permeability transition, and activation of apoptotic cascades, all favoring cardiomyocyte death. Ischemia-induced mitochondrial damage carried forward into reperfusion further amplifies these mechanisms of mitochondrial-driven myocyte injury. Interruption of mitochondrial respiration during early reperfusion by pharmacologic blockade of electron transport or even recurrent hypoxia or brief ischemia paradoxically decreases cardiac injury. It increasingly appears that the cardioprotective paradigms of ischemic preconditioning and postconditioning utilize modulation of mitochondrial oxidative metabolism as a key effector mechanism. The initially counterintuitive approach to inhibit mitochondrial respiration provides a new cardioprotective paradigm to decrease cellular injury during both ischemia and reperfusion.
Acute activation of NHE3 by dexamethasone correlates with activation of SGK1 and requires a functional glucocorticoid receptor
Authors: Wang Dongsheng , Zhang Huanchun , Lang Florian , Yun C. Chris
Published: September 2006

Glucocorticoids stimulate the intestinal absorption of Na+ and water partly by regulation of the Na+/H+ exchanger 3 (NHE3). Previous studies have shown both genomic and nongenomic regulation of NHE3 by glucocorticoids. Serum and glucocorticoid-inducible kinase 1 (SGK1) has been shown to be part of this cascade, where phosphorylation of NHE3 by SGK1 initiates the translocation of NHE3 to the cell surface. In the present work, we examined a series of changes in SGK1 and NHE3 induced by glucocorticoids using human colonic Caco-2 and opossum kidney cells. We found that dexamethasone rapidly stimulated SGK1 mRNAs, but a significant change in protein abundance was not detected. Instead, there was an increase in SGK1 kinase activity as early as at 2 h. An increase in NHE3 protein abundance was not detected until 12 h of dexamethasone exposure, although the transport activity was significantly stimulated at 4 h. These data demonstrate that the changes of SGK1 precede those of NHE3. Chronic regulation (24 h) of NHE3 was blocked completely by prevention of protein synthesis with cycloheximide or actinomycin D and by the glucocorticoid receptor blocker RU486. The acute effect of dexamethasone was similarly abrogated by RU486, but was insensitive to cycloheximide and actinomycin D. Similarly, the stimulation of SGK1 activity by dexamethasone was blocked by RU486 but not by actinomycin D. Together, these data show that the acute effect of glucocorticoids on NHE3 is mediated by a glucocorticoid receptor dependent mechanism that activates SGK1 in a nongenomic manner.
Polyamines are required for phospholipase C-γ1expression promoting intestinal epithelial restitution after wounding
Authors: Rao Jaladanki N. , Liu Lan , Zou Tongtong , Marasa Bernard S. , Boneva Dessy , Wang Shelley R. , Malone Debra L. , Turner Douglas J. , Wang Jian-Ying
Published: September 2006

Intestinal mucosal restitution occurs by epithelial cell migration, rather than by proliferation, to reseal superficial wounds after injury. Polyamines are essential for the stimulation of intestinal epithelial cell (IEC) migration during restitution in association with their ability to regulate Ca2+homeostasis, but the exact mechanism by which polyamines induce cytosolic free Ca2+concentration ([Ca2+]cyt) remains unclear. Phospholipase C (PLC)-γ1catalyzes the formation of inositol ( 1 , 4 , 5 )-trisphosphate (IP3), which is implicated in the regulation of [Ca2+]cytby modulating Ca2+store mobilization and Ca2+influx. The present study tested the hypothesis that polyamines are involved in PLC-γ1activity, regulating [Ca2+]cytand cell migration after wounding. Depletion of cellular polyamines by α-difluoromethylornithine inhibited PLC-γ1expression in differentiated IECs (stable Cdx2-transfected IEC-6 cells), as indicated by substantial decreases in levels of PLC-γ1mRNA and protein and its enzyme product IP3. Polyamine-deficient cells also displayed decreased [Ca2+]cytand inhibited cell migration. Decreased levels of PLC-γ1by treatment with U-73122 or transfection with short interfering RNA specifically targeting PLC-γ1also decreased IP3, reduced resting [Ca2+]cytand Ca2+influx after store depletion, and suppressed cell migration in control cells. In contrast, stimulation of PLC-γ1by 2,4,6-trimethyl- N-( meta-3-trifluoromethylphenyl)-benzenesulfonamide induced IP3, increased [Ca2+]cyt, and promoted cell migration in polyamine-deficient cells. These results indicate that polyamines are absolutely required for PLC-γ1expression in IECs and that polyamine-mediated PLC-γ1signaling stimulates cell migration during restitution as a result of increased [Ca2+]cyt.
Gadolinium does not blunt the cardiovascular responses at the onset of voluntary static exercise in cats: a predominant role of central command
Authors: Matsukawa Kanji , Nakamoto Tomoko , Inomoto Atsushi
Published: September 2006

The cardiovascular adaptation at the onset of voluntary static exercise is controlled by the autonomic nervous system. Two neural mechanisms are responsible for the cardiovascular adaptation: one is central command descending from higher brain centers, and the other is a muscle mechanosensitive reflex from activation of mechanoreceptors in the contracting muscles. To examine which mechanism played a major role in producing the initial cardiovascular adaptation during static exercise, we studied the effect of intravenous administration of gadolinium (55 μmol/kg), a blocker of stretch-activated ion channels, on the increases in heart rate (HR) and mean arterial blood pressure (MAP) at the onset of voluntary static exercise (pressing a bar with a forelimb) in conscious cats. HR increased by 31 ± 5 beats/min and MAP increased by 15 ± 1 mmHg at the onset of voluntary static exercise. Gadolinium affected neither the baseline values nor the initial increases of HR and MAP at the onset of exercise, although the peak force applied to the bar tended to decrease to 65% of the control value before gadolinium. Furthermore, we examined the effect of gadolinium on the reflex responses in HR and MAP (18 ± 7 beats/min and 30 ± 6 mmHg, respectively) during passive mechanical stretch of a forelimb or hindlimb in anesthetized cats. Gadolinium significantly blunted the passive stretch-induced increases in HR and MAP, suggesting that gadolinium blocks the stretch-activated ion channels and thereby attenuates the reflex cardiovascular responses to passive mechanical stretch of a limb. We conclude that the initial cardiovascular adaptation at the onset of voluntary static exercise is predominantly induced by feedforward control of central command descending from higher brain centers but not by a muscle mechanoreflex.
Protein kinase C activation inhibits Cav1.3 calcium channel at NH2-terminal serine 81 phosphorylation site
Authors: Baroudi Ghayath , Qu Yongxia , Ramadan Omar , Chahine Mohamed , Boutjdir Mohamed
Published: September 2006

The Cav1.3 (α1D) variant of L-type Ca2+ channels plays a vital role in the function of neuroendocrine and cardiovascular systems. In this article, we report on the molecular and functional basis of α1D Ca2+ channel modulation by protein kinase C (PKC). Specifically, we show that the serine 81 (S81) phosphorylation site at the NH2-terminal region plays a critical role in α1D Ca2+ channel modulation by PKC. The introduction of a negatively charged residue at position 81, by converting serine to aspartate, mimicked the PKC phosphorylation effect on α1D Ca2+ channel. The modulation of α1D Ca2+ channel by PKC was prevented by dialyzing cells with a 35-amino acid peptide mimicking the α1D NH2-terminal region comprising S81. In addition, the data revealed that only βII- and εPKC isozymes are implicated in this regulation. These novel findings have significant implications in the pathophysiology of α1D Ca2+ channel and in the development of PKC isozyme-targeted therapeutics.
Induction of matrix metalloproteinase-2 enhances systemic arterial contraction after hypoxia
Authors: He Jeff Z. , Quan Adrian , Xu Yi , Teoh Hwee , Wang Guilin , Fish Jason E. , Steer Brent M. , Itohara Shigeyoshi , Marsden Philip A. , Davidge Sandra T. , Ward Michael E.
Published: September 2006

This study was carried out to determine the role of increased vascular matrix metalloproteinase-2 (MMP-2) expression in the changes in systemic arterial contraction after prolonged hypoxia. Rats and mice were exposed to hypoxia (10% and 8% O2, respectively) or normoxia (21% O2) for 16 h, 48 h, or 7 days. Aortae and mesenteric arteries were either mounted in organ bath myographs or frozen in liquid nitrogen. MMP-2 inhibition with cyclic CTTHWGFTLC (CTT) reduced contraction to phenylephrine (PE) in aortae and mesenteric arteries from rats exposed to hypoxia for 7 days but not in vessels from normoxic rats. Similarly, CTT reduced contraction to Big endothelin-1 (Big ET-1) in aortae from rats exposed to hypoxia for 7 days. Responses to PE were reduced in hypoxic MMP-2−/− mice compared with MMP-2+/+ mice. Increased contraction to Big ET-1 after hypoxia was observed in MMP-2+/+ mice but not in MMP-2−/− mice. Rat aortic MMP-2 and membrane type 1 (MT1)-MMP protein levels and MMP activity were increased after 7 days of hypoxia. Rat aortic MMP-2 and MT1-MMP mRNA levels were increased in the deep medial vascular smooth muscle. We conclude that hypoxic induction of MMP-2 expression potentiates contraction in systemic conduit and resistance arteries. This may preserve the capacity to regulate the systemic circulation in the transition between the alterations in vascular tone and structural remodeling that occurs during prolonged hypoxic epochs.
Toll-like receptor 2 modulates left ventricular function following ischemia-reperfusion injury
Authors: Sakata Yasushi , Dong Jian-Wen , Vallejo Jesus G. , Huang Chien-Hua , Baker J. Scott , Tracey Kevin J. , Tacheuchi Osamu , Akira Shizuo , Mann Douglas L.
Published: September 2006

Production of proinflammatory cytokines contributes to cardiac dysfunction during ischemia-reperfusion. The principal mechanism responsible for the induction of this innate stress response during periods of myocardial ischemia-reperfusion remains unknown. Toll-like receptor 2 (TLR2) is a highly conserved pattern recognition receptor that has been implicated in the innate immune response to a variety of pathogens. However, TLR2 may also mediate inflammation in response to noninfectious injury. We therefore hypothesized that TLR2 is essential for modulating myocardial inflammation and left ventricular (LV) function during ischemia-reperfusion injury. Susceptibility to myocardial ischemia-reperfusion injury following ischemia-reperfusion was determined in Langendorff-perfused hearts isolated from wild-type mice and mice deficient in TLR2 (TLR2D) and Toll interleukin receptor domain-containing adaptor protein. After ischemia-reperfusion, contractile performance was significantly impaired in hearts from wild-type mice as demonstrated by a lower recovery of LV developed pressure relative to TLR2D hearts. Creatinine kinase levels were similar in both groups after reperfusion. Contractile dysfunction in wild-type hearts was associated with elevated cardiac levels of TNF and IL-1β. Ischemia-reperfusion-induced LV dysfunction was reversed by treatment with the recombinant TNF blocking protein etanercept. These studies show for the first time that TLR2 signaling importantly contributes to the LV dysfunction that occurs following ischemia-reperfusion. Thus disruption of TLR2-mediated signaling may be helpful to induce immediate or delayed myocardial protection from ischemia-reperfusion injury.
Dexamethasone-induced protein degradation in cultured myotubes is p300/HAT dependent
Authors: Yang Hongmei , Wei Wei , Menconi Michael , Hasselgren Per-Olof
Published: September 2006

Muscle proteolysis during sepsis and other catabolic conditions is, at least in part, regulated by glucocorticoids. Dexamethasone-treated myotubes are a commonly used in vitro model of muscle wasting. We reported recently that treatment of cultured L6 myotubes with dexamethasone resulted in increased gene and protein expression of the nuclear cofactor p300 but it is not known whether glucocorticoids upregulate p300 histone acetyl transferase (HAT) activity in muscle and whether p300/HAT activity regulates glucocorticoid-induced muscle proteolysis. Here, we found that treatment of cultured L6 myotubes with dexamethasone resulted in increased nuclear p300/HAT activity. Treatment of myotubes with p300 siRNA or transfection of muscle cells with a plasmid expressing p300 that was mutated in its HAT activity domain blocked the dexamethasone-induced increase in protein degradation, supporting a role of p300/HAT in glucocortiocoid-induced muscle proteolysis. In addition to increased HAT activity, treatment of the myotubes with dexamethasone resulted in reduced nuclear expression and activity of histone deacetylases (HDACs) 3 and 6. When myotubes were treated with the HDAC inhibitor trichostatin A, protein degradation increased to the same degree as in dexamethasone-treated myotubes. The results suggest that glucocorticoids increase HAT and decrease HDAC activities in muscle, changes that both favor hyperacetylation. The results also provide evidence that dexamethasone-induced protein degradation in cultured myotubes is, at least in part, regulated by p300/HAT activity.
Renovascular BKCachannels are not activated in vivo under resting conditions and during agonist stimulation
Authors: Magnusson Linda , Sorensen Charlotte Mehlin , Braunstein Thomas Hartig , Holstein-Rathlou Niels-Henrik , Salomonsson Max
Published: September 2006

We investigated the role of large-conductance Ca2+-activated K+(BKCa) channels for the basal renal vascular tone in vivo. Furthermore, the possible buffering by BKCaof the vasoconstriction elicited by angiotensin II (ANG II) or norepinephrine (NE) was investigated. The possible activation of renal vascular BKCachannels by cAMP was investigated by infusing forskolin. Renal blood flow (RBF) was measured in vivo using electromagnetic flowmetry or ultrasonic Doppler. Renal preinfusion of tetraethylammonium (TEA; 3.0 μmol/min) caused a small reduction of baseline RBF, but iberiotoxin (IBT; 0.3 nmol/min) did not have any effect. Renal injection of ANG II (1–4 ng) or NE (10–40 ng) produced a transient decrease in RBF. These responses were not affected by preinfusion of TEA or IBT. Renal infusion of the BKCaopener NS-1619 (90.0 nmol/min) did not affect basal RBF or the response to NE, but it attenuated the response to ANG II. Coadministration of NS-1619 with TEA or IBT abolished this effect. Forskolin caused renal vasodilation that was not inhibited by IBT. The presence of BKCachannels in the preglomerular vessels was confirmed by immunohistochemistry. Despite their presence, there is no indication for a major role for BKCachannels in the control of basal renal tone in vivo. Furthermore, BKCachannels do not have a buffering effect on the rat renal vascular responses to ANG II and NE. The fact that NS-1619 attenuates the ANG II response indicates that the renal vascular BKCachannels can be activated under certain conditions.
Hepatic and muscle insulin action during late pregnancy in the dog
Authors: Connolly Cynthia C. , Papa Tracy , Smith Marta S. , Lacy D. Brooks , Williams Phillip E. , Moore Mary Courtney
Published: September 2006

We evaluated the effects of physiologic increases in insulin on hepatic and peripheral glucose metabolism in nonpregnant (NP) and pregnant (P; 3rd trimester) conscious dogs ( n = 9 each) using tracer and arteriovenous difference techniques during a hyperinsulinemic euglycemic clamp. Insulin was initially (−150 to 0 min) infused intraportally at a basal rate. During 0–120 min (Low Insulin), the rate was increased by 0.2 mU·kg−1·min−1, and from 120 to 240 min (High Insulin) insulin was infused at 1.5 mU·kg−1·min−1. Insulin concentrations were significantly higher in NP than P during all periods. Matched subsets ( n = 5 NP and 6 P) were identified. In the subsets, insulin was 7 ± 1, 9 ± 1, and 28 ± 3 μU/ml (basal, Low Insulin, and High Insulin, respectively) in NP, and 5 ± 1, 7 ± 1, and 27 ± 3 μU/ml in P. Net hepatic glucose output was suppressed similarly in both subsets (≥50% with Low Insulin, 100% with High Insulin), as was endogenous glucose rate of appearance. During High Insulin, NP dogs required more glucose (10.8 ± 1.5 vs. 6.2 ± 1.0 mg·kg−1·min−1, P < 0.05), and hindlimb (primarily skeletal muscle) glucose uptake tended to be greater in NP than P (18.6 ± 2.5 mg/min vs. 13.6 ± 2.0 mg/min, P = 0.06). The normal canine liver remains insulin sensitive during late pregnancy. Differing insulin concentrations in pregnant and nonpregnant women and excessive insulin infusion rates may explain previous findings of hepatic insulin resistance in healthy pregnant women.
Excretion and conservation of glycerol, and expression of aquaporins and glyceroporins, during cold acclimation in Cope's gray tree frogHyla chrysoscelis
Authors: Zimmerman Sarah L. , Frisbie James , Goldstein David L. , West Jennifer , Rivera Kevin , Krane Carissa M.
Published: September 2006

Cope's gray tree frog Hyla chrysoscelis accumulates glycerol during cold acclimation. We hypothesized that, during this process, gray tree frogs adjust renal filtration and/or reabsorption rates to retain accumulated glycerol. During cold acclimation, plasma concentrations of glycerol rose >200-fold, to 51 mmol/l. Although fractional water reabsorption decreased, glomerular filtration rate (GFR) and, consequently, urine flow were <5% of warm levels, and fractional glycerol reabsorption increased. In contrast, dehydrated frogs increased fractional water reabsorption, decreased GFR, and did not accumulate glycerol. We hypothesized that expression of proteins from the aquaporin (AQP)/glyceroporin (GLP) family was associated with changing patterns of water and glycerol movement. We cloned the cDNA for three such proteins, quantified mRNA expression in nine tissues using real-time quantitative PCR, and functionally characterized them using a Xenopus oocyte expression system. HC-1, an AQP1-like water channel conferring low glycerol permeability, is expressed ubiquitously in warm- and cold-acclimated tissues. HC-2, a water channel most similar to AQP2, is primarily expressed in organs of osmoregulation. HC-3, which is most similar to AQP3, is functionally characterized as a GLP, with low permeability to water but high permeability to glycerol. Aspects of expression levels and functional characteristics varied between cold and warm conditions for each of the three AQPs, suggesting a complex pattern of involvement in osmoregulation related to thermal acclimation.
Type IV carbonic anhydrase is present in the gills of spiny dogfish (Squalus acanthias)
Authors: Gilmour K. M. , Bayaa M. , Kenney L. , McNeill B. , Perry S. F.
Published: September 2006

Physiological and biochemical studies have provided indirect evidence for a membrane-associated carbonic anhydrase (CA) isoform, similar to mammalian type IV CA, in the gills of dogfish ( Squalus acanthias). This CA isoform is linked to the plasma membrane of gill epithelial cells by a glycosylphosphatidylinositol anchor and oriented toward the plasma, such that it can catalyze the dehydration of plasma HCO[Formula: see text] ions. The present study directly tested the hypothesis that CA IV is present in dogfish gills in a location amenable to catalyzing plasma HCO[Formula: see text] dehydration. Homology cloning techniques were used to assemble a 1,127 base pair cDNA that coded for a deduced protein of 306 amino acids. Phylogenetic analysis suggested that this protein was a type IV CA. For purposes of comparison, a second cDNA (1,107 base pairs) was cloned from dogfish blood; it encoded a deduced protein of 260 amino acids that was identified as a cytosolic CA through phylogenetic analysis. Using real-time PCR and in situ hybridization, mRNA expression for the dogfish type IV CA was detected in gill tissue and specifically localized to pillar cells and branchial epithelial cells that flanked the pillar cells. Immunohistochemistry using a polyclonal antibody raised against rainbow trout type IV CA revealed a similar pattern of CA IV immunoreactivity and demonstrated a limited degree of colocalization with Na+-K+-ATPase immunoreactivity. The presence and localization of a type IV CA isoform in the gills of dogfish is consistent with the hypothesis that branchial membrane-bound CA with an extracellular orientation contributes to CO2excretion in dogfish by catalyzing the dehydration of plasma HCO[Formula: see text] ions.
Modeling Gravity-Dependent Plasticity of the Angular Vestibuloocular Reflex With a Physiologically Based Neural Network
Authors: Xiang Yongqing , Yakushin Sergei B. , Cohen Bernard , Raphan Theodore
Published: September 2006

A neural network model was developed to explain the gravity-dependent properties of gain adaptation of the angular vestibuloocular reflex (aVOR). Gain changes are maximal at the head orientation where the gain is adapted and decrease as the head is tilted away from that position and can be described by the sum of gravity-independent and gravity-dependent components. The adaptation process was modeled by modifying the weights and bias values of a three-dimensional physiologically based neural network of canal–otolith-convergent neurons that drive the aVOR. Model parameters were trained using experimental vertical aVOR gain values. The learning rule aimed to reduce the error between eye velocities obtained from experimental gain values and model output in the position of adaptation. Although the model was trained only at specific head positions, the model predicted the experimental data at all head positions in three dimensions. Altering the relative learning rates of the weights and bias improved the model-data fits. Model predictions in three dimensions compared favorably with those of a double-sinusoid function, which is a fit that minimized the mean square error at every head position and served as the standard by which we compared the model predictions. The model supports the hypothesis that gravity-dependent adaptation of the aVOR is realized in three dimensions by a direct otolith input to canal–otolith neurons, whose canal sensitivities are adapted by the visual-vestibular mismatch. The adaptation is tuned by how the weights from otolith input to the canal–otolith-convergent neurons are adapted for a given head orientation.
Neurophysiology of Prehension. I. Posterior Parietal Cortex and Object-Oriented Hand Behaviors
Authors: Gardner Esther P. , Babu K. Srinivasa , Reitzen Shari D. , Ghosh Soumya , Brown Alice S. , Chen Jessie , Hall Anastasia L. , Herzlinger Michael D. , Kohlenstein Jane B. , Ro Jin Y.
Published: September 2006

Hand manipulation neurons in areas 5 and 7b/anterior intraparietal area (AIP) of posterior parietal cortex were analyzed in three macaque monkeys during a trained prehension task. Digital video recordings of hand kinematics synchronized to neuronal spike trains were used to correlate firing rates of 128 neurons with hand actions as the animals grasped and lifted rectangular and round objects. We distinguished seven task stages: approach, contact, grasp, lift, hold, lower, and relax. Posterior parietal cortex (PPC) firing rates were highest during object acquisition; 88% of task-related area 5 neurons and 77% in AIP/7b fired maximally during stages 1, 2, or 3. Firing rates rose 200–500 ms before contact, peaked at contact, and declined after grasp was secured. 83% of area 5 neurons and 72% in AIP/7b showed significant increases in mean rates during approach as the fingers were preshaped for grasp. Somatosensory signals at contact provided feedback concerning the accuracy of reach and helped guide the hand to grasp sites. In error trials, tactile information was used to abort grasp, or to initiate corrective actions to achieve task goals. Firing rates declined as lift began. 41% of area 5 neurons and 38% in AIP/7b were inhibited during holding, and returned to baseline when grasp was relaxed. Anatomical connections suggest that area 5 provides somesthetic information to circuits linking AIP/7b to frontal motor areas involved in grasping. Area 5 may also participate in sensorimotor transformations coordinating reach and grasp behaviors and provide on-line feedback needed for goal-directed hand movements.
Estimation of Height and Body Mass Index from Demi-Span in Elderly Individuals
Authors: Weinbrenner Tanja , Vioque Jesús , Barber Xavier , Asensio Laura
Published: September 2006

Background: Obtaining accurate height and, consequently, body mass index (BMI) measurements in elderly subjects can be difficult due to changes in posture and loss of height during ageing. Measurements of other body segments can be used as an alternative to estimate standing height, but population- and age-specific equations are necessary. Objective: Our objectives were to validate existing equations, to develop new simple equations to predict height in an elderly Spanish population and to assess the accuracy of the BMI calculated by estimated height from the new equations. Methods: We measured height and demi-span in a representative sample of 592 individuals, 271 men and 321 women, 65 years and older (mean ± SD, 73.8 ± 6.3 years). We suggested equations to predict height from demi-span by multiple regression analyses and performed an agreement analysis between measured and estimated indices. Results: Height estimated from demi-span correlated significantly (p < 0.001) with measured height (men: r = 0.708, women: r = 0.625). The best prediction equations were as follows: men, height (in cm) = 77.821 + (1.132 × demi-span in cm) + (–0.215 × 5-year age category); women: height (in cm) = 88.854 + (0.899 × demi-span in cm) + (–0.692 × 5-year age category). No significant differences between the mean values of estimated and measured heights were found for men (–0.03 ± 4.6 cm) or women (–0.02 ± 4.1 cm). The BMI derived from measured height did not differ significantly from the BMI derived from estimated height either. Conclusion: Predicted height values from equations based on demi-span and age may be acceptable surrogates to derive accurate nutritional indices such as the BMI, particularly in elderly populations, where height may be difficult to measure accurately.
YAC/BAC contig spanning the MHC class III region of cattle
Authors: Gelhaus A. , Heβ M. , Förster B. , Goldammer T. , Schwerin M. , Horstmann R.D.
Published: September 2006

A contig of the class III region of the bovine major histocompatibility complex (MHC) was established from bacterial and yeast artificial chromosomes using PCR and BAC-end sequencing. The marker content of individual clones was determined by gene and BAC-end specific PCR, and the location of genes and BAC-ends was confirmed analyzing somatic hybrid cells. A comparative analysis indicated that the content and order of MHC class III genes is strongly conserved between cattle and other mammalian species. Fluorescence in situ hybridization localized the bovine class III region to BTA23q21→q22. The results show that the collection of sequenced BAC-ends is a powerful resource for generating high-resolution comparative chromosome maps.
Genomic structure of swine taste receptor family 1 member 3, TAS1R3, and its expression in tissues
Authors: Kiuchi S. , Yamada T. , Kiyokawa N. , Saito T. , Fujimoto J. , Yasue H.
Published: September 2006

Taste receptor family 1 member 3, TAS1R3, is shown to be involved in sweet and umami tastes in mouse, and the nucleotide sequence of the gene has been reported in rat, gorilla, and human. Pigs are frequently used as models for human diseases, and are also considered to be source animals for xenotransplantation to humans due to their anatomical and physiological similarities to humans. Therefore, in the present study, the genomic structure of the swine TAS1R3 gene was determined, and TAS1R3 expression was studied in various swine tissues. The gene was shown to reside on swine chromosome 6q22→q23, from which three types of mRNAs were generated: 3,752 bp derived from six exons in tongue, 3,704 bp from six exons and 3,630 bp from seven exons in testis. The 6 exons/5 introns were structurally similar to those of humans and mice, but the 7 exons/6 introns structure of TAS1R3 was first observed in swine. High expressions of TAS1R3 were revealed in tongue, kidney, and testis by real-time PCR. The expression profile of the tissues except for kidney was similar to that of mouse. When in situ hybridization using an RNA probe for TAS1R3 was performed on swine tongue and testis tissues, TAS1R3 expressions were revealed in tongue circumvallate papillae, fungiform papillae, mucosal epithelium, follicular B lymphocytes, lymphocytes in submucosal tissues of lingual tonsil, and spermatogenic cells. Using peripheral mature B lymphocytes, the expression of TAS1R3 in B lymphocytes was further confirmed by real-time PCR and sequencing of the real-time PCR product.
Dynamic increase of a 45,X cell line in a patient with multicentric ring Y chromosomes
Authors: DesGroseilliers M. , Fortin F. , Lafrenière A.-M. , Brochu P. , Lemyre E. , Lemieux N.
Published: September 2006

Because ring Y chromosomes are unstable during cell division most reported patients are mosaics, usually including a 45,X cell line. The phenotype varies from normal males or females with streak gonads to sexual ambiguities. We present here the case of a 23-year-old man who was referred at 11 years for growth delay. The GTG-banded karyotypes of lymphocytes revealed two cell lines: 46,X,dic r(Y) seen in 76% of the metaphases analyzed and 45,X (24%). Karyotypes and FISH were performed eight years later with the following probes: DYZ3 (Y centromere), SRY (sex-region of the Y), DYZ1 (Yq heterochromatin), CEPX/Y (X centromere and Yq heterochromatin), TelVysion Xp/Yp, Xq/Yq (X and Y subtelomeres), pan-telomeric, cosmid clones LLycos130G04 and LLycos37C09 (PARII), and BAC clone RP11-5C5 (Yq11.223). The results showed an increase in the 45,X cell line (60%) and a reduction in the 46,X,dic r(Y) cell line (36.4%). The use of Yq probes showed that the ring Y chromosome was dicentric. In addition, other ring Y structures were observed. The breakpoints occurred in proximal Yp11.32 or in Yp11.31 distal to SRY and in Yq12 distal to the PARII region. Therefore, most of the Y remained intact and all genes, with the exception of those in PARI, are present in double dosage in the dic r(Y). The level of mosaicism was important in defining the phenotype.
Quantitative Analysis of Chondroitin Sulfate in Tear Fluids following Laser in situ Keratomileusis
Authors: Nishio Masaya , Arai Kiyomi
Published: September 2006

Purpose: To report chondroitin sulfate (CS) concentrations in tear fluid following laser in situ keratomileusis (LASIK). Methods: Fourteen eyes that underwent LASIK were enrolled. We measured the CS isomers chondroitin 4 sulfate and chondroitin 6 sulfate using an enzyme-linked immunosorbent assay preoperatively and postoperatively on days 1 and 4, week 1, and 1 and 3 months. Results: The chondroitin 4 sulfate concentration remained unchanged from preoperative values. The chondroitin 6 sulfate concentration increased temporarily 1 day postoperatively and gradually decreased thereafter. Conclusions: CS in tear fluids participates in wound healing after LASIK. Clarifying its role in tear fluids will contribute to improved LASIK outcomes.
Androgen Status of the Nonautoimmune Dry Eye Subtypes
Authors: Tamer Cengaver , Oksuz Hüseyin , Sogut Sadık
Published: September 2006

Purpose: To evaluate androgen levels of patients diagnosed with nonautoimmune dry eye, either with meibomian gland dysfunction (MGD) or without MGD (non-MGD), and normal control subjects. This is a prospective, comparative, case-control study. Methods: Sixty-four (32 men and 32 women) subjects were enrolled for each of the three diagnostic groups. All dry eye patients were symptom positive. Nonfasting testosterone (T), sex hormone-binding globulin, serum albumin, dehydroepiandrosterone (DHEA), and DHEA sulphate levels of all study participants were determined using either automated immunoenzymatic assay, or standard radioimmunoassay. Analysis of variance was used to compare androgen levels among the three diagnostic groups in a gender-based design, followed by post-hoc multiple comparisons with the Tukey honestly significant difference test. Results: Mean T levels in men and women of the three diagnostic groups were not significantly different (p = 0.808, p = 0.156, respectively; ANOVA). Statistical analyses of the three diagnostic groups revealed a significant difference for men and women in bioavailable T levels (p = 0.002, p = 0.014, respectively; ANOVA), DHEA levels (p = 0.009, p = 0.004, respectively; ANOVA), and DHEA sulphate levels (p = 0.001, p = 0.001, respectively; ANOVA), whereas there was no statistically significant difference between non-MGD dry eye patients and controls for any of the measured androgen levels according to the post-hoc tests. Conclusion: This study demonstrates that the androgen pool of nonautoimmune dry eye patients with MGD is significantly depleted compared with that of non-MGD and control cases.
The Efficacy of Postenucleation Saline Wash and the Effect of Different Antimicrobial Agents on Microbial Contamination of Donor Eyes
Authors: Panda Anita , Saxena Rohit , Vajpayee Rasik B. , Satpathy Gita , Angra S.K. , Sethi Harinder Singh
Published: September 2006

Objectives: To evaluate the efficacy of postenucleation saline wash and the effect of different antimicrobial agents on the microbial contamination of donor eyes. Methods: Two hundred donor eyes were given saline wash and treated with any one of the following 5 randomly selected antimicrobial solutions: 1% povidone-iodine for 3 min, 0.3% gentamycin for 10 min, 0.3% ciprofloxacin for 10 min, a combination of neomycin 1,700 IU, gramicidin 0.025% and polymyxin B 5,000 IU (Neosporin®) for 10 min and a combination of 0.3% amikacin for 10 min, followed by 2.5% cefazolin for 10 min. Limbal swabs were sent for culture before and after saline wash and after treatment with antimicrobial agents. Results: On culture of the pretreatment swabs, 77.5% were positive for growth with 75.5% bacterial and 11.5% fungal. Coagulase-negative Staphylococcus (29.1%) was the most common bacterial contamination followed by Pseudomonas aeruginosa (18.5%), Acinetobacter sp. (18.5%) and Alcaligenes faecalis (13.2%). A 20-ml sterile saline wash resulted in a 20% decrease (p < 0.01) in the amount of contamination. The maximum antimicrobial effect with regard to bacterial decontamination was achieved with povidone-iodine (64% decrease in the amount of contamination, p < 0.01) followed by ciprofloxacin (47.6% decrease, p < 0.05), the combination of cefazolin and amikacin (42.5%, p < 0.05), Neosporin (38.5%, p < 0.05) and then gentamycin (21.7%, p = NS). Conclusions: A thorough saline wash and treatment with 1% povidone-iodine for 3 min is a more effective method for the decontamination of donor eyes as compared to most currently available and frequently used antibiotics.
Pyridoxamine Inhibits Maillard Reactions in Diabetic Rat Lenses
Authors: Padival Simi , Nagaraj Ram H.
Published: September 2006

Purpose: Advanced glycation end products (AGEs) play an important role in protein modification during cataract formation. Along with sugars, α-dicarbonyl compounds, such as methylglyoxal (MGO), have been implicated in AGE formation. Here we report the effect of pyridoxamine (PM) on AGEs and AGE-precursor-metabolizing enzymes in diabetic rat lenses and organ-cultured rat lenses. Methods: Diabetes was induced in rats by injecting streptozotocin. Diabetic and nondiabetic control rats were treated with PM in drinking water for 20 weeks. Rat lenses were organ cultured with normal or high glucose. We measured lens glutathione (GSH), MGO, AGEs and activities of aldose reductase and glyoxalase I. Results: Treatment of diabetic rats with PM inhibited both argpyrimidine and pentosidine formation when compared to untreated diabetic animals and nondiabetic control animals. Incubation of lenses with 30 mMD-glucose caused an elevation of these AGEs. Addition of 250 µM PM along with glucose resulted in inhibition of AGE formation in organ-cultured lenses. The glyoxalase I activity was significantly reduced in diabetic rats; PM treatment inhibited such a reduction. The activity of aldose reductase was elevated in diabetic lenses; PM treatment further enhanced its activity. Conclusion: Our results suggest that PM can inhibit AGE formation in the diabetic lens by enhancing the activity of aldose reductase and reacting with precursors of AGEs.
Protective Effect of Aspirin against Dexamethasone-Induced Cataract in Cultured Rat Lens
Authors: Yan Hong , Wang Jianwei , Liu Bing , Shang Lijun
Published: September 2006

Purpose: To investigate the effect of aspirin on dexamethasone-induced cataract formation in cultured rat lenses. Methods: One hundred and forty-eight lenses were divided into 3 groups and cultured in vitro: control (DMEM), cataract (DMEM + 10 µM dexamethasone), aspirin (DMEM + 10 µM dexamethasone + 2 mM aspirin). Following incubation, the transparency of the lenses was evaluated daily using a dissecting microscope. Twelve lenses from each group were homogenized and the activities of enzymes (catalase, superoxide dismutase and lactate dehydrogenase) from supernatants were measured after 1, 3, 5 and 7 days of incubation, respectively. The ultrastructure of lenses from the control and cataract groups was observed on the completion of 7-day incubation. Results: Opacity was induced by dexamethasone in the nuclear region of the rat lenses. Lenses in the control group exhibited mist-like opacity and lenses in the cataract group showed dense nuclear opacity, whereas lenses in the aspirin-treated group only had a visible demarcation between nuclear and cortical regions at day 7. The activities of catalase, superoxide dismutase and lactate dehydrogenase in the cataract group decreased in a time-dependent manner. There was no significant loss of enzyme activities in either the control or the aspirin group throughout the incubation period. An orderly arrangement of fiber cells was noted, and the cell membrane, cell junction and organelles were normal in the control group. However, in the cataract group the arrangement of fiber cells was untidy and the lenses contained abnormal-appearing cells. The group exhibited swollen mitochondria, a large number of vacuoles and expanded extracellular lacunae. Conclusions:Dexamethasone induces nuclear cataract in the organ-cultured rat lens by chemically modifying proteins, including enzymes. The enzymes, including those that normally eliminate radial oxygen species, could be especially vulnerable. Aspirin significantly inhibits dexamethasone-induced cataract formation by inhibiting inactivation of those enzymes.
Differential Role of Rho-Kinase in Pathological and Physiological Cardiac Hypertrophy in Rats
Authors: Balakumar Pitchai , Singh Manjeet
Published: September 2006

The present study was undertaken to investigate the effect of fasudil, a specific Rho-kinase inhibitor, in pathological cardiac hypertrophy induced by partial abdominal aortic constriction (PAAC) for 4 weeks in comparison with physiological cardiac hypertrophy caused by chronic swimming training (CST) for 8 weeks in rats. Fasudil (15 and 30 mg/kg day–1 p.o.) treatment was started 3 days before PAAC and CST, and was continued for 4 weeks in PAAC and 8 weeks in the CST experimental model. Left ventricular (LV) function and LV hypertrophy were assessed by measuring LVDP, +dp/dtmax, –dp/dtmax, ratio of LV weight to body weight (LVW/BW), LV wall thickness (LVWT), LV collagen content, protein content and RNA concentration. Further, venous pressure (VP) and mean arterial blood pressure (MABP) were recorded. Moreover, DNA gel electrophoresis was employed to assess myocardial cell death. PAAC but not CST produced LV dysfunction by decreasing LVDP, +dp/dtmax, –dp/dtmax and increasing LV collagen content. Further, PAAC and CST were noted to produce LV hypertrophy by increasing LVW/BW, LVWT, LV protein content and LV RNA concentration. Moreover, in contrast to CST, PAAC has significantly increased VP, MABP and LV necrotic cell death. Fasudil, a Rho-kinase inhibitor, markedly attenuated PAAC-induced LV dysfunction, LV hypertrophy, increase in VP, MABP and LV necrotic cell death. However, it did not modulate the CST-induced LV hypertrophy. These results have implicated Rho-kinase in PAAC-induced LV dysfunction and pathological cardiac hypertrophy. However, Rho-kinase may not be involved in CST-induced physiological cardiac hypertrophy.
Potential role of activated platelets in homing of human endothelial progenitor cells to subendothelial matrix
Authors: Lev Eli , Estrov Zeev , Aboulfatova Khatira , Harris David , Granada Juan , Alviar Carlos , Kleiman Neal , Dong Jing-fei
Published: September 2006

Endothelial progenitor cells (EPCs) mobilize from the bone marrow in response to tissue injury and participate in vascular repair. However, there is limited data about the homing mechanisms of EPCs to vascular injury sites. Recently animal experiments indicated that platelets playa role in recruitment of EPCs to injury sites. However, data on the possible interaction between platelets and EPCs within the human system are limited. We, therefore, examined in-vitro human platelet-EPC interaction under static and flow conditions. Human EPCs were isolated from donated buffy coats by magnetic microbeads and flow cytometry cell sorting using CD133 and VEGFR-2, respectively, as markers. Platelets were tested in the form of washed platelets, platelet rich plasma or whole blood. EPCs formed heterotypic aggregates with resting platelets under static conditions, an interaction that was greatly enhanced when platelets were activated by collagen, ADP or thrombin-activation peptide. The platelet-EPC interaction was inhibited by antibodies to P-selectin or P-selectin glycoprotein ligand-1 (PSGL-1), but not by antibodies to glycoproteins Ib-IX-V or IIb/IIIa. When perfused over activated platelets under shear stress of 2.5 dyn/cm2, EPCs tethered to platelayers and either adhered immediately or rolled a short distance before adhering. In addition, platelets promoted the colonization of adherent EPCs in culture conditions. Consistent with recent animal studies, these findings demonstrate that human EPCs interact in vitro with activated platelets under static and flow conditions, mediated through P-selectin–PSGL-1 interaction. This interaction may be a central mechanism for homing of EPCs to vascular injury sites.
Review on the value of graduated elastic compression stockings after deep vein thrombosis
Authors: Kakkos Stavros , Daskalopoulou Stella , Daskalopoulos Marios , Nicolaides Andrew , Geroulakos George
Published: September 2006

Graduated elastic compression stockings (GECS) are commonly used in the primary prevention of deep vein thrombosis (DVT); however, their role in preventing recurrent DVT and also post-thrombotic syndrome is less well established. The aim of this review was to investigate the effect of GECS after DVT. A literature search was performed by two independent searchers in order to identify randomised controlled trials on the effect of GECS in preventing recurrent DVT and post-thrombotic syndrome. Four randomised trials, including 537 patients, were identified. Two of the studies demonstrated that below-knee GECS significantly reduced post-thrombotic syndrome during follow-up, while a smaller study showed equivocal results. GECS reduced the incidence of post-thrombotic syndrome from 54% to 25.2% [relative risk (RR) 0.47, 95% confidence interval (CI) 0.36-0.61] with the number needed to treat (NNT) being 4 (95% CI 2.7-5.0).The rate of recurrent asymptomatic DVT was also significantly reduced by GECS (RR 0.20, 95% CI 0.06-0.64; NNT 5); the reduction in symptomatic DVT was not significant (RR 0.79, 95% CI 0.50-1.26; NNT 34). In conclusion, there is level Ia evidence to suggest that GECS can significantly reduce the incidence of post-thrombotic syndrome (PTS) after DVT, and therefore these should be routinely prescribed. The evidence for recurrent DVT is less conclusive. Further research is needed towards standardising PTS diagnostic criteria and evaluating more effective preventive measures after DVT.
The gender-specific role of polymorphisms from the fibrinolytic, renin-angiotensin, and bradykinin systems in determining plasma t-PA and PAI-1 levels
Authors: Asselbergs Folkert , Williams Scott , Hebert Patricia , Coffey Christopher , Hillege Hans , Navis Gerjan , Vaughan Douglas , van Gilst Wiek , Moore Jason
Published: September 2006

Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) directly influence thrombus formation and degradation and thus risk for arterial thrombosis. We report here results from a genetic analysis of plasma t-PA and PAI-1 levels in a large population-based sample from the PREVEND study in Groningen, the Netherlands (n=2,527). We measured polymorphisms from genes of the fibrinolytic system, the reninangiotensin system (RAS), and the bradykinin system. We found that males had higher levels of natural-log transformed t-PA, and PAI-1 (P < 0.01) compared to females. When stratifying females by menopausal status, PAI-1 levels were only significantly different between pre-menopausal females and males (p<0.001). Furthermore, we found that age, body mass index, and waist-to-hip ratio were significant predictors of t-PA and PAI-1 in both females and males, and that the regression relationships between these factors and plasma t-PA and PAI-1 were dependent on gender. In addition, we found that the PAI-1 4G/5G polymorphism was a significant predictor of PAI-1 levels in both females and males, that the angiotensin II type I receptor A1166C wasa significant predictor of t-PA and PAI-1 levels in females, and that the bradykinin receptor B2 58CT polymorphism was a significant predictor of t-PA levels in females. In conclusion, this large population-based study showed that t-PA and PAI-1 levels are determined by several demographic and genetic factors involved in the fibrinolytic, RAS and bradykinin system. In addition, the results support the idea that the biology of t-PA and PAI-1 is different between females and males.