bluuebunny/crossref_metadata_2025 huggingface dataset:
Selectivity for
d
-Lactate Incorporation into the Peptidoglycan Precursors of
Lactobacillus plantarum
: Role of Aad, a VanX-Like
d
-Alanyl-
d
-Alanine Dipeptidase
Authors: Deghorain Marie , Goffin Philippe , Fontaine Laetitia , Mainardi Jean-Luc , Daniel Richard , Errington Jeff , Hallet Bernard , Hols Pascal
Published: March 2007

Lactobacillus plantarum
produces peptidoglycan precursors ending in
d
-lactate instead of
d
-alanine, making the bacterium intrinsically resistant to vancomycin. The ligase Ddl of
L. plantarum
plays a central role in this specificity by synthesizing
d
-alanyl-
d
-lactate depsipeptides that are added to the precursor peptide chain by the enzyme MurF. Here we show that
L. plantarum
also encodes a
d
-Ala-
d
-Ala dipeptidase, Aad, which eliminates
d
-alanyl-
d
-alanine dipeptides that are produced by the Ddl ligase, thereby preventing their incorporation into the precursors. Although
d
-alanine-ended precursors can be incorporated into the cell wall, inactivation of Aad failed to suppress growth defects of
L. plantarum
mutants deficient in
d
-lactate-ended precursor synthesis.
Identification of an AU-rich Translational Enhancer within theEscherichia coli fepBLeader RNA
Authors: Hook-Barnard India G. , Brickman Timothy J. , McIntosh Mark A.
Published: March 2007

ThefepBgene encodes a periplasmic binding protein that is essential for the uptake of ferric enterobactin byEscherichia coli. Its transcription is regulated in response to iron levels by the Fur repressor. ThefepBtranscript includes a 217-nucleotide leader sequence with several features suggestive of posttranscriptional regulation. To investigate thefepBleader for its contribution tofepBexpression, defined deletions and substitution mutations in the leader were characterized usingfepB-phoAtranslational fusions. ThefepBleader was found to be necessary for maximalfepBexpression, primarily due to the influence of an AU-rich translational enhancer (TE) located 5′ to the Shine-Dalgarno sequence. Deletions or substitutions within the TE sequence decreasedfepB-phoAexpression fivefold. RNase protection and in vitro transcription-translation assays demonstrated that the TE augmented translational efficiency, as well as RNA levels. Moreover, primer extension inhibition assays showed that the TE increases ribosome binding. In contrast to the enhancing effect of the TE, the naturalfepBGUG start codon decreased ribosome binding and reducedfepBexpression 2.5-fold compared with the results obtained with leaders bearing an AUG initiation codon. Thus, the TE-GUG organization infepBresults in an intermediate level of expression compared to the level with AUG, with or without the TE. Furthermore, we found that the TE-GUG sequence is conserved among the eight gram-negative strains examined that havefepBgenes, suggesting that this organization may provide a selective advantage.
In what ways can human skeletal remains be used to understand health and disease from the past?
Authors: Metcalfe Neil H
Published: April 2007

Disease and illness in previous generations can be investigated using palaeopathology. This article describes the commonly used techniques in palaeopathology, includes examples of how such techniques are able to formulate data on a variety of health issues that occurred in the past and suggests how these data can be relevant today.
DNA sequence variations of metalloproteinases: their role in asthma and COPD
Authors: Sampsonas Fotis , Kaparianos Alexander , Lykouras Dimosthenis , Karkoulias Kiriakos , Spiropoulos Kostas
Published: April 2007

Asthma and chronic obstructive pulmonary disease (COPD) are complex genetic diseases that cause considerable morbidity and mortality worldwide. Genetic variability interacting with environmental and ethnic factors is presumed to cause tobacco smoke susceptibility and to influence asthma severity. A disintegrin and metalloproteinase 33 (ADAM33) and matrix metalloproteinase-9 (MMP9) appear to have important roles in asthma and COPD pathogenesis. ADAM33 and MMP9 genetic alterations could possibly contribute to the establishment and progression of these multifactorial diseases, although their association with the clinical phenotypes has not yet been elucidated. However, the occurrence of these alterations does not always result in clear disease, implying that either they are an epiphenomenon or they are in proximity to the true causative alteration. This review summarises the most recent literature dealing with the genetic variations of metalloproteinases and outlines their potential pathogenetic outcome.
BUBBLING GEOMETRIES FOR HALF-BPS WILSON LINES
Authors: YAMAGUCHI SATOSHI
Published: April 2007

We consider the supergravity backgrounds that correspond to supersymmetric Wilson line operators in the context of AdS/CFT correspondence. We study the gravitino and dilatino conditions of the IIB supergravity under the appropriate ansatz, and obtain some necessary conditions for a supergravity background that preserves the same symmetry as the supersymmetric Wilson lines. The supergravity solutions are characterized by continuous version of Maya diagrams. This diagram is related to the eigenvalue distribution of the Gaussian matrix model. We also consider the similar backgrounds of the 11-dimensional supergravity.
NEW DISCRETE STATES IN TWO-DIMENSIONAL SUPERGRAVITY
Authors: POLYAKOV DIMITRI
Published: April 2007

Two-dimensional string theory is known to contain the set of discrete states that are the SU (2) multiplets generated by the lowering operator of the SU (2) current algebra. Their structure constants are defined by the area preserving diffeomorphisms in two dimensions. In this paper we show that the interaction of d = 2 superstrings with the superconformal β - γ ghosts enlarges the actual algebra of the dimension 1 currents and hence the new ghost-dependent discrete states appear. Generally, these states are the SU (N) multiplets if the algebra includes the currents of ghost numbers n : -N ≤ n ≤ N - 2, not related by picture changing. We compute the structure constants of these ghost-dependent discrete states for N = 3 and express them in terms of SU (3) Clebsch–Gordan coefficients, relating this operator algebra to the volume preserving diffeomorphisms in d = 3. For general N, the operator algebra is conjectured to be isomorphic to SDiff (N). This points at possible holographic relations between two-dimensional superstrings and field theories in higher dimensions.
THE EARLY HISTORY OF HAND SURGERY IN THE PHILIPPINES AND HIGHLIGHTS IN MY EXPERIENCE AT THE NATIONAL ORTHOPAEDIC HOSPITAL MANDALUYONG AND THE OUR LADY OF LOURDES HOSPITAL, MANILA
Authors: Inocentes Eugenio M.
Published: April 2007

Several years ago, while attending a Philippines Orthopaedic Association (PDA) Annual Convention, held at the Westin Philippine Plaza Hotel, Manila in December, I had the opportunity to meet with Professor Yoshikazu Ikuta, a well-known microsurgery and hand surgeon from Japan and one of the foreign guest speakers. I had been invited to work with him at the Armed Forces of the Philippines (AFP) Medical Center on the case of a high ranking general of the AFP, with a hand contracture disability problem. The case was referred to him by Dr. Evaristo Sanchez, Chief of Orthopaedics and the Commanding General of the AFP Medical Center. He had been pre-scheduled for surgery the next day, a Sunday morning, the day before Prof. Ikuta was due to return to Japan.

After a brief examination and evaluation of the generals affected hand, in the operating room with Prof. Ikuta, just before he was placed under general anaesthesia, we performed the operation together.

The operation did not involve microsurgery. The procedures done were multiple combined Bunnell-Zancolli pulley advancements and MP-joint volar capsulorraphies plus flexor tendon releases in the volar forearm, which although quite extensive, were only palliative, to minimise and improve on the contracture deformities, in preparation for a final re-evaluation for possible later, more definitive tendon transfers for hand function.

However, I never received any further information regarding the results of our surgery.

Recently, I have been honoured and invited again by Prof. Ikuta, presently the Editor-in-Chief of the Hand Surgery Journal (Asian Volume), this time to write the history of hand surgery in the Philippines and add to it, "Highlights in my experience at the National Orthopaedic Hospital, Mandaluyong, and the Our Lady of Lourdes Hospital, Manila", the last portion of which is on paralytic disabilities of the Hand.

I am deeply grateful to Prof. Ikuta for giving me this honour and opportunity to present the total experience, favourable and unfavourable, of a hand surgeon from a developing country, like the Philippines. Furthermore, this would afford me also, the chance to be able to make known to readers of this now prestigious journal, the philosophical thoughts which led me to unwittingly originate or come up with and develop a few of my own "Long Tendon Rerouting Procedures" which may possibly and hopefully merit as this author's title contribution to surgery of the hands.
OSTEOCHONDRAL DESTRUCTION IN THE HAND FOLLOWING BEE STINGS: A CASE REPORT OF AN INFANT
Authors: Haga Nobuhiko , Masuda Kazuhiro , Takikawa Kazuharu
Published: April 2007

We report an infant who developed arthritis with osteochondral destruction in a hand after being stung by bees. The clinical findings resembled those reported as "beekeeper's arthropathy", but the radiological findings were more severe. Histology of the resected specimen revealed fibrous granulation tissue with infiltration of inflammation cells.
Cardioprotective effects of stretch are mediated by activation of sarcolemmal, not mitochondrial, ATP-sensitive potassium channels
Authors: Mosca Susana M.
Published: March 2007

To determine whether sarcolemmal and/or mitochondrial ATP-sensitive potassium (KATP) channels (sarcKATP, mitoKATP) are involved in stretch-induced protection, isolated isovolumic rat hearts were assigned to the following protocols: nonstretched hearts were subjected to 20 min of global ischemia (Is) and 30 min of reperfusion, and before Is stretched hearts received 5 min of stretch + 10 min of no intervention. Stretch was induced by a transient increase in left ventricular end-diastolic pressure (LVEDP) from 10 to 40 mmHg. Other hearts received 5-hydroxydecanoate (5-HD; 100 μM), a selective inhibitor of mitoKATP, or HMR-1098 (20 μM), a selective inhibitor of sarcKATP, before the stretch protocol. Systolic function was assessed through left ventricular developed pressure (LVDP) and maximal rise in velocity of left ventricular pressure (+dP/d tmax) and diastolic function through maximal decrease in velocity of left ventricular pressure (−dP/d tmax) and LVEDP. Lactate dehydrogenase (LDH) release and ATP content were also measured. Stretch resulted in a significant increase of postischemic recovery and attenuation of diastolic stiffness. At 30 min of reperfusion LVDP and +dP/d tmaxwere 87 ± 4% and 92 ± 6% and −dP/d tmaxand LVEDP were 95 ± 9% and 10 ± 4 mmHg vs. 57 ± 6%, 53 ± 6%, 57 ± 10%, and 28 ± 5 mmHg, respectively, in nonstretched hearts. Stretch increased ATP content and did not produce LDH release. 5-HD did not modify and HMR-1098 prevented the protection achieved by stretch. Our results show that the beneficial effects of stretch on postischemic myocardial dysfunction, cellular damage, and energetic state involve the participation of sarcKATPbut not mitoKATP.
Vascular endothelial growth factor-C stimulates the lymphatic pump by a VEGF receptor-3-dependent mechanism
Authors: Breslin Jerome W. , Gaudreault Nathalie , Watson Katherine D. , Reynoso Rashell , Yuan Sarah Y. , Wu Mack H.
Published: March 2007

Vascular endothelial growth factor (VEGF)-C plays an important role in lymphangiogenesis; however, functional responses of lymphatic vessels to VEGF-C have not been characterized. We tested the hypothesis that VEGF-C-induced activation of VEGF receptor (VEGFR)-3 increases lymphatic pump output. We examined the in vivo pump activity of rat mesenteric collecting lymphatics using intravital microscopy during basal conditions and during treatment with 1 nM recombinant VEGF-C, the selective VEGFR-3 agonist VEGF-Cys156Ser mutation (C156S; 1 nM), or 0.1 nM VEGF-A. Their specific responses were also analyzed during selective inhibition of VEGFR-3 with MAZ-51. Contraction frequency, end-diastolic diameter, end-systolic diameter, stroke volume index, pump flow index, and ejection fraction were evaluated. We also assessed arteriolar diameter and microvascular extravasation of FITC-albumin. The results show that both VEGF-C and VEGF-C156S significantly increased contraction frequency, end-diastolic diameter, stroke volume index, and pump flow index in a time-dependent manner. VEGF-A caused a different response characterized by a significantly increased stroke volume after 30 min of treatment. MAZ-51 (5 μM) caused tonic constriction and decreased contraction frequency. In addition, 0.5 and 5 μM MAZ-51 attenuated VEGF-C- and VEGF-C156S-induced lymphatic pump activation. VEGF-A caused vasodilation of arterioles, whereas VEGF-C and VEGF-C156S did not significantly alter arteriolar diameter. Also, VEGF-A and VEGF-C caused increased microvascular permeability, whereas VEGF-C156S did not. Our results demonstrate that VEGF-C increases lymphatic pumping through VEGFR-3. Furthermore, changes in microvascular hemodynamics are not required for VEGFR-3-mediated changes in lymphatic pump activity.
Transient middle cerebral artery occlusion causes different structural, mechanical, and myogenic alterations in normotensive and hypertensive rats
Authors: Jiménez-Altayó Francesc , Martín Abraham , Rojas Santiago , Justicia Carles , Briones Ana M. , Giraldo Jesús , Planas Anna M. , Vila Elisabet
Published: March 2007

Transient focal cerebral ischemia in the rat alters vessel properties, and spontaneously hypertensive rats (SHR) show a poorer outcome after ischemia. In the present study we examined the role of hypertension on vessel properties after ischemia-reperfusion. The right middle cerebral artery (MCA) was occluded (90 min) and reperfused (24 h) in SHR ( n = 12) and Wistar-Kyoto rats (WKY; n = 11). Sham-operated rats (SHR, n = 10; WKY, n = 10) were used as controls. The structural, mechanical, and myogenic properties of the MCA were assessed by pressure myography. Nuclei distribution and elastin content and organization were analyzed by confocal microscopy. Infarct volume was larger in SHR than in WKY rats. Ischemia-reperfusion induced adventitial hypertrophy associated with an increase in the total number of adventitial cells. In addition, fenestrae area and arterial distensibility increased and myogenic tone decreased in the MCA of WKY rats after ischemia-reperfusion. Hypertension per se induced hypertrophic inward remodeling. Ischemia-reperfusion decreased the cross-sectional area of the MCA in SHR, without significant changes in distensibility, despite an increase in fenestrae area. In addition, MCA myogenic properties were not altered after ischemia-reperfusion in SHR. Our results indicate that in normotensive rats, MCA develops a compensatory mechanism (i.e., enhanced distensibility and decreased myogenic tone) that counteracts the effect of ischemia-reperfusion and ensures correct cerebral irrigation. These compensatory mechanisms are lost in hypertension, thereby explaining, at least in part, the greater infarct volume observed in SHR.
Effect of intracellular Ca2+ and action potential duration on L-type Ca2+ channel inactivation and recovery from inactivation in rabbit cardiac myocytes
Authors: Altamirano Julio , Bers Donald M.
Published: March 2007

Ca2+ current ( ICa) recovery from inactivation is necessary for normal cardiac excitation-contraction coupling. In normal hearts, increased stimulation frequency increases force, but in heart failure (HF) this force-frequency relationship (FFR) is often flattened or reversed. Although reduced sarcoplasmic reticulum Ca2+-ATPase function may be involved, decreased ICa availability may also contribute. Longer action potential duration (APD), slower intracellular Ca2+ concentration ([Ca2+]i) decline, and higher diastolic [Ca2+]i in HF could all slow ICa recovery from inactivation, thereby decreasing ICa availability. We measured the effect of different diastolic [Ca2+]i on ICa inactivation and recovery from inactivation in rabbit cardiac myocytes. Both ICa and Ba2+ current ( IBa) were measured. ICa decay was accelerated only at high diastolic [Ca2+]i (600 nM). IBa inactivation was slower but insensitive to [Ca2+]i. Membrane potential dependence of ICa or IBa availability was not affected by [Ca2+]i <600 nM. Recovery from inactivation was slowed by both depolarization and high [Ca2+]i. We also used perforated patch with action potential (AP)-clamp and normal Ca2+ transients, using various APDs as conditioning pulses for different frequencies (and to simulate HF APD). Recovery of ICa following longer APD was increasingly incomplete, decreasing ICa availability. Trains of long APs caused a larger ICa decrease than short APD at the same frequency. This effect on ICa availability was exacerbated by slowing twitch [Ca2+]i decline by ∼50%. We conclude that long APD and slower [Ca2+]i decline lead to cumulative inactivation limiting ICa at high heart rates and might contribute to the negative FFR in HF, independent of altered Ca2+ channel properties.
Role of genetic and environmental influences on heart rate variability in middle-aged men
Authors: Uusitalo A. L. T. , Vanninen E. , Levälahti E. , Battié M. C. , Videman T. , Kaprio J.
Published: March 2007

Our aim was to estimate causal relationships of genetic factors and different specific environmental factors in determination of the level of cardiac autonomic modulation, i.e., heart rate variability (HRV), in healthy male twins and male twins with chronic diseases. The subjects were 208 monozygotic (MZ, 104 healthy) and 296 dizygotic (DZ, 173 healthy) male twins. A structured interview was used to obtain data on lifetime exposures of occupational loading, regularly performed leisure-time sport activities, coffee consumption, smoking history, and chronic diseases from 12 yr of age through the present. A 5-min ECG at supine rest was recorded for the HRV analyses. In univariate statistical analyses based on genetic models with additive genetic, dominance genetic, and unique environmental effects, genetic effects accounted for 31–57% of HRV variance. In multivariate statistical analysis, body mass index, percent body fat, coffee consumption, smoking, medication, and chronic diseases were associated with different HRV variables, accounting for 1–11% of their variance. Occupational physical loading and leisure-time sport activities did not account for variation in any HRV variable. However, in the subgroup analysis of healthy and diseased twins, occupational loading explained 4% of the variability in heart periods. Otherwise, the interaction between health status and genetic effects was significant for only two HRV variables. In conclusion, genetic factors accounted for a major portion of the interindividual differences in HRV, with no remarkable effect of health status. No single behavioral determinant appeared to have a major influence on HRV. The effects of medication and diseases may mask the minimal effect of occupational loading on HRV.
Possible roles of neuropeptide Y Y3-receptor subtype in rat aortic endothelial cell proliferation under hypoxia, and its specific signal transduction
Authors: Chen Zhi-Yong , Feng Guo-Gang , Nishiwaki Kimitoshi , Shimada Yasuhiro , Fujiwara Yoshihiro , Komatsu Toru , Ishikawa Naohisa
Published: March 2007

The present study was undertaken to determine whether neuropeptide Y (NPY) induces proliferation of rat aortic endothelial cells (RAECs). Since NPY increased the permeability of RAEC monolayers to large molecules via the NPY Y3receptor, RAEC proliferation has been evaluated in terms of NPY-receptor subtypes and also intracellular mechanisms. RAECs were incubated with gases containing 20, 15, or 10% O2and a certain amount of N2, depending on the O2content in 5% CO2incubators. NPY (10−9–10−6M) increased the RAEC numbers under hypoxic conditions, such as 15 or 10% O2. Peptide YY elicited no proliferative effect on RAEC, and NPY-(18-36) inhibited the NPY-induced increase in cell number, suggesting that NPY increases the RAEC count through the NPY Y3receptor. Pertussis toxin, U-73122, GF-109203X, myristorylated autocamtide-2-related inhibitory peptide, and wortmannin inhibited the NPY-induced proliferation of RAEC concentration dependently. DY9760e little affected the proliferation caused by NPY. ML-9 and imatinib actually enhanced the NPY-induced proliferation of cells. These results indicated that the NPY Y3receptor is coupled with Giprotein, and that NPY-induced increases in RAEC proliferation are mediated by phospholipase C-protein kinase C and/or phosphatidylinositol 3-kinase pathways. In intracellular Ca2+-calmodulin-dependent pathways, calmodulin-dependent protein kinase II partly participates in the NPY-induced cell proliferation. Regarding the previously reported effect of NPY on the permeability of RAEC monolayers to large molecules, it is probable that protein kinase C and phosphatidylinositol 3-kinase pathways are activated for both permeability and cell proliferation induced by NPY under hypoxia, relevant to new insights into the roles of NPY in ischemia-hypoxia.
Inhibition of histone deacetylase on ventricular remodeling in infarcted rats
Authors: Lee Tsung-Ming , Lin Mei-Shu , Chang Nen-Chung
Published: March 2007

Histone deacetylase (HDAC) determines the acetylation status of histones and, thereby, controls the regulation of gene expression. HDAC inhibitors have been shown to inhibit cardiomyocyte growth in vitro and in vivo. We assessed whether HDAC inhibitors exert a beneficial effect on the remodeling heart in infarcted rats. At 24 h after ligation of the left anterior descending artery, male Wistar rats were randomized to vehicle, HDAC inhibitors [valproic acid (VPA) and tributyrin], an agonist of HDAC (theophylline), VPA + theophylline, or tributyrin + theophylline for 4 wk. Significant ventricular hypertrophy was detected as increased myocyte size at the border zone isolated by enzymatic dissociation after infarction. Cardiomyocyte hypertrophy and collagen formation at the remote region and border zone were significantly attenuated by VPA and tributyrin with a similar potency compared with that induced by the vehicle. Left ventricular shortening fraction was significantly higher in the VPA- and tributyrin-treated groups than in the vehicle-treated group. Increased synthesis of atrial natriuretic peptide mRNA after infarction was confirmed by RT-PCR, consistent with the results of immunohistochemistry and Western blot for acetyl histone H4. The beneficial effects of VPA and tributyrin were abolished by theophylline, implicating HDAC as the relevant target. Inhibition of HDAC by VPA or tributyrin can attenuate ventricular remodeling after infarction. This might provide a worthwhile therapeutic target.
Impairment of cardiac insulin signaling and myocardial contractile performance in high-cholesterol/fructose-fed rats
Authors: Deng Jen-Ying , Huang Jiung-Pang , Lu Long-Sheng , Hung Li-Man
Published: March 2007

Although insulin resistance is recognized as a potent and prevalent risk factor for coronary heart disease, less is known as to whether insulin resistance causes an altered cardiac phenotype independent of coronary atherosclerosis. In this study, we investigated the relationship between insulin resistance and cardiac contractile dysfunctions by generating a new insulin resistance animal model with rats on high cholesterol-fructose diet. Male Sprague-Dawley rats were given high cholesterol-fructose (HCF) diet for 15 wk; the rats developed insulin resistance syndrome characterized by elevated blood pressure, hyperlipidemia, hyperinsulinemia, impaired glucose tolerance, and insulin resistance. The results show that HCF induced insulin resistance not only in metabolic-response tissues (i.e., liver and muscle) but also in the heart as well. Insulin-stimulated cardiac glucose uptake was significantly reduced after 15 wk of HCF feeding, and cardiac insulin resistance was associated with blunted Akt-mediated insulin signaling along with glucose transporter GLUT4 translocation. Basal fatty acid transporter FATP1 levels were increased in HCF rat hearts. The cardiac performance of the HCF rats exhibited a marked reduction in cardiac output, ejection fraction, stroke volume, and end-diastolic volume. It also showed decreases in left ventricular end-systolic elasticity, whereas the effective arterial elasticity was increased. In addition, the relaxation time constant of left ventricular pressure was prolonged in the HCF group. Overall, these results indicate that insulin resistance reduction of cardiac glucose uptake is associated with defects in insulin signaling. The cardiac metabolic alterations that impair contractile functions may lead to the development of cardiomyopathy.
On the role of junctin in cardiac Ca2+handling, contractility, and heart failure
Authors: Gergs Ulrich , Berndt Tobias , Buskase Jan , Jones Larry R. , Kirchhefer Uwe , Müller Frank U. , Schlüter Klaus-Dieter , Schmitz Wilhelm , Neumann Joachim
Published: March 2007

Junctin is a transmembrane protein located at the cardiac junctional sarcoplasmic reticulum (SR) and forms a quaternary complex with the Ca2+release channel, triadin and calsequestrin. Impaired protein interactions within this complex may alter the Ca2+sensitivity of the Ca2+release channel and may lead to cardiac dysfunction, including hypertrophy, depressed contractility, and abnormal Ca2+transients. To study the expression of junctin and, for comparison, triadin, in heart failure, we measured the levels of these proteins in SR from normal and failing human hearts. Junctin was below our level of detection in SR membranes from failing human hearts, and triadin was downregulated by 22%. To better understand the role of junctin in the regulation of Ca2+homeostasis and contraction of cardiac myocytes, we used an adenoviral approach to overexpress junctin in isolated rat cardiac myocytes. A recombinant adenovirus encoding the green fluorescent protein served as a control. Infection of myocytes with the junctin-expressing virus resulted in an increased RNA and protein expression of junctin. Ca2+transients showed a decreased maximum Ca2+amplitude, and contractility of myocytes was depressed. Our results demonstrate that an increased expression of junctin is associated with an impaired Ca2+homeostasis. Downregulation of junctin in human heart failure may thus be a compensatory mechanism.
Alterations to myofibrillar protein function in nonischemic regions of the heart early after myocardial infarction
Authors: Rao Vijay S. , La Bonte Laura R. , Xu Yaqin , Yang Zequan , French Brent A. , Guilford William H.
Published: March 2007

Remote-zone left ventricular dysfunction (LVD) contributes to global reductions in contractile function after localized myocardial infarction (MI). However, the molecular mechanisms underlying this form of LVD are not clear. This study tested the hypothesis that myofibrillar protein function is directly affected in remote-zone LVD early after MI. Cardiac myosin and native thin filaments were purified from mouse myocardium taken from both the nonnecrotic zone adjacent to and the nonischemic zone remote from an infarct induced by 1 h of coronary occlusion followed by 24 h of reperfusion. Thin filament velocities were measured using the in vitro motility assay. Results showed that overall function was significantly reduced in samples from both the adjacent (43 ± 12% of control, n = 7) and remote (53 ± 8% of control, n = 13) zones when compared with control proteins ( P < 0.05). Myosin from the remote zone propelled control thin filaments at reduced velocities similar to those measured above. In contrast, the Ca2+sensitivity of remote-zone thin filaments over control myosin was unchanged from control thin filaments (half-maximal at pCa 6.32 ± 0.08 and 6.27 ± 0.06, respectively) but showed a 20% increase in velocity at saturating Ca2+that parallels an increase in tropomyosin phosphorylation. Myosin dysfunction may be related to oxidation of cysteines in the myosin heavy chains or carbonylation of myosin binding protein-C. We hypothesize that phosphorylation of tropomyosin may serve a compensatory role, augmenting contraction during periods of oxidative stress when myosin function is compromised.
An analysis of the effects of stretch on IGF-I secretion from rat ventricular fibroblasts
Authors: Hu Betty S. , Landeen Lee K. , Aroonsakool Nakon , Giles Wayne R.
Published: March 2007

Mechanical force can induce a number of fundamental short- and long-term responses in myocardium. These include alterations in ECM, activation of cell-signaling pathways, altered gene regulation, changes in cell proliferation and growth, and secretion of a number of peptides and growth factors. It is now known that a number of these autocrine/paracrine factors are secreted from both cardiomyocytes and ventricular cardiac fibroblasts (CFb) in response to stretch. One such substance is IGF-I. IGF-I is an important autocrine/paracrine factor that can regulate physiological or pathophysiological responses, such as hypertrophy. In this study, we addressed the possible effects of mechanical perturbation, biaxial strain, on IGF-I secretion from adult rat CFb. CFb were subjected to either static stretch (3–10%) or cyclic stretch (10%; 0.1–1 Hz) over a 24-h period. IGF-1 secretion from CFb in response to selected stretch paradigms was examined using ELISA to measure IGF-I concentrations in conditioned media. Static stretch did not result in any measurable modulation of IGF-I secretion from CFb. However, cyclic stretch significantly increased IGF-I secretion from CFb in a frequency- and time-dependent manner compared with nonstretched controls. This stretch-induced increase in secretion was relatively insensitive to changes in extracellular [Ca2+] or to block of L-type Ca2+ channels. In contrast, thapsigargin, an inhibitor of sarco(endo)plasmic reticulum Ca2+ ATPase, remarkably decreased stretch-induced IGF-I secretion from CFb. We further show that IGF-I can upregulate mRNA expression of atrial natriuretic peptide in myocytes. In summary, cyclic stretch can significantly increase IGF-I secretion from CFb, and this effect is dependent on a thapsigargin-sensitive pool of intracellular [Ca2+].
TGF-β-neutralizing antibodies improve pulmonary alveologenesis and vasculogenesis in the injured newborn lung
Authors: Nakanishi Hidehiko , Sugiura Takahiro , Streisand James B. , Lonning Scott M. , Roberts Jesse D.
Published: March 2007

Pulmonary injury is associated with the disruption of alveologenesis in the developing lung and causes bronchopulmonary dysplasia (BPD) in prematurely born infants. Transforming growth factor (TGF)-β is an important regulator of cellular differentiation and early lung development, and its levels are increased in newborn lung injury. Although overexpression of TGF-β in the lungs of newborn animals causes pathological features that are consistent with BPD, the role of endogenous TGF-β in the inhibition of the terminal stage of lung development is incompletely understood. In this investigation, the hypothesis that O2-induced injury of the maturing lung is associated with TGF-β-mediated disruption of alveologenesis and microvascular development was tested using a murine model of BPD. Here we report that treatment of developing mouse lungs with TGF-β-neutralizing antibodies attenuates the increase in pulmonary cell phospho-Smad2 nuclear localization, which is indicative of augmented TGF-β signaling, associated with pulmonary injury induced by chronic inhalation of 85% oxygen. Importantly, the neutralization of the abnormal TGF-β activity improves quantitative morphometric indicators of alveologenesis, extracellular matrix assembly, and microvascular development in the injured developing lung. Furthermore, exposure to anti-TGF-β antibodies is associated with improved somatic growth in hyperoxic mouse pups and not with an increase in pulmonary inflammation. These studies indicate that excessive pulmonary TGF-β signaling in the injured newborn lung has an important role in the disruption of the terminal stage of lung development. In addition, they suggest that anti-TGF-β antibodies may be an effective therapy for preventing some important developmental diseases of the newborn lung.
Transfection with Anti-p65 Intrabody Suppresses Invasion and Angiogenesis in Glioma Cells by Blocking Nuclear Factor-κB Transcriptional Activity
Authors: Li Liang , Gondi Christopher S. , Dinh Dzung H. , Olivero William C. , Gujrati Meena , Rao Jasti S.
Published: April 2007

Purpose: The strategy of intracellular antibodies to neutralize the function of target proteins has been widely developed for cancer research. This study used an intrabody against p65 subunit to prevent nuclear factor κB (NF-κB) transcriptional activity in glioma cells and to inhibit the expression of its target genes involved in the invasion and angiogenesis of human gliomas.

Experimental Design: A single-chain fragment of antibody variable region (scFv) against p65 was prepared using phage display technique. We then prepared an anti-p65 intrabody construct (pFv/nu) by cloning the scFv-encoding sequence into the mammalian nuclear-targeting vector, pCMV/myc/nuc.

Results: p65 expression in human glioma cells (U251 and] U87) transfected with pFv/nu was significantly decreased. We showed that NF-κB nuclear translocation and its DNA binding activity were blocked via intrabody transfection in electrophoretic mobility shift assays and the inhibition of NF-κB activity in nucleus resulted in the decreasing expression and bioactivity of matrix metalloproteinase-9, urokinase-type plasminogen activator receptor, urokinase-type plasminogen activator, and vascular endothelial growth factor. The intrabody transfected glioma cells showed a markedly lower level of invasion in Matrigel invasion assay. The capillary-like structure formation of endothelial cells was also repressed by coculture with the intrabody transfected glioma cells or exposure to their conditional medium. Intrabody transfection neither induced apoptosis nor altered cell proliferation in U251 and U87 cells as compared with the control vector pCMV/nu. After the injection of pFv/nu-transfected glioma cells, preestablished tumors were almost completely regressed when compared with mock, pCMV/nu, and pGFP/nu.

Conclusion: Blocking NF-κB activity via the nuclear intrabody expression might be a potential approach for cancer therapy.
Mcl-1 Is a Relevant Therapeutic Target in Acute and Chronic Lymphoid Malignancies: Down-Regulation Enhances Rituximab-Mediated Apoptosis and Complement-Dependent Cytotoxicity
Authors: Hussain Syed-Rehan A. , Cheney Carolyn M. , Johnson Amy J. , Lin Thomas S. , Grever Michael R. , Caligiuri Michael A. , Lucas David M. , Byrd John C.
Published: April 2007

Purpose: The antiapoptotic Bcl-2 family member protein Mcl-1 is dynamically regulated in transformed B-cells, has a short mRNA and protein half-life, and is rapidly processed during apoptosis. Multiple therapies cause down-regulation of Mcl-1 in chronic and acute lymphoid leukemia (CLL and ALL) cells. Mcl-1 has also been reported to mediate resistance to rituximab in CLL. We therefore investigated whether direct reduction of Mcl-1 was sufficient to induce apoptosis and increase sensitivity to rituximab.

Experimental Design: We used Mcl-1–specific small interfering RNA in ALL cell lines and tumor cells from CLL patients to block transcription of Mcl-1.

Results: We show that Mcl-1 down-regulation alone is sufficient to promote mitochondrial membrane depolarization and apoptosis in ALL and CLL cells. Given the importance of rituximab in B-cell malignancies, we next assessed the influence of Mcl-1 down-regulation on antibody-mediated killing. Mcl-1 down-regulation by small interfering RNA increased sensitivity to rituximab-mediated killing both by direct apoptosis and complement-dependent cytotoxicity, but did not enhance antibody-dependent cellular cytotoxicity.

Conclusions: These results show that Mcl-1 is a relevant therapeutic target for ALL and CLL, and its down-regulation has the potential to enhance the therapeutic effect of rituximab in CD20-bearing lymphoid cells.
3q26 Amplification and Polysomy of Chromosome 3 in Squamous Cell Lesions of the Lung: A Fluorescence In situ Hybridization Study
Authors: Pelosi Giuseppe , Del Curto Barbara , Trubia Maurizio , Nicholson Andrew G. , Manzotti Michela , Veronesi Giulia , Spaggiari Lorenzo , Maisonneuve Patrick , Pasini Felice , Terzi Alberto , Iannucci Antonio , Viale Giuseppe
Published: April 2007

Purpose: An overlapping area of gain at 3q26 has been reported in lung squamous cell carcinoma (SCC), but whether this also occurs in preneoplastic/preinvasive squamous cell proliferations and early-stage invasive carcinomas of the lung is still unknown.

Experimental Design: We evaluated the prevalence and the clinicopathologic implications of 3q26 amplification and polysomy of chromosome 3 in 31 preneoplastic/preinvasive squamous cell lesions of the bronchial mucosa and in 139 early-stage invasive pulmonary SCC, both of limited growth within the bronchial wall [early hilar SCC (EHSCC)] and involving the pulmonary parenchyma [parenchyma-infiltrating SCC (PISCC)]. Moreover, mRNA expression of two candidate genes (h-TERC and SKI-like), both mapping to the minimal common amplification region, was also studied by quantitative real-time reverse transcription-PCR.

Results: 3q26 amplification and polysomy of chromosome 3 were confined to malignant samples, with 37% of invasive SCC, and 27% of severe dysplasias/in situ carcinomas showing these chromosomal abnormalities. Amplification (with minimal common amplification region at 3q26.2), polysomy 3, concurrent amplification and polysomy 3, or other changes (monosomy) were found in 25 SCC and 1 dysplasia, 24 and 2, 2 and 0, and 1 and 0, respectively. Amplification was significantly associated with EHSCC, polysomy 3 with PISCC. 3q26 amplification correlated with increased tumor diameter and a history of smoking, whereas polysomy 3 correlated with tumor diameter, pT class, and p53, p21, and fascin immunoreactivity. No relationship of either 3q26 gain or polysomy was found with patients' survival. Overexpression of h-TERC or SKI-like mRNA was found in 3q26-amplified or polysomic SCC, with higher levels of h-TERC in the former and of SKI-like in the latter.

Conclusions: 3q26 amplification and chromosome 3 polysomy may be related to the development of invasive SCC, with differential distribution in tumor subsets, despite substantial histologic uniformity. Both h-TERC and SKI-like may be involved in tumor progression.
Involvement of c-Jun-JNK Pathways in the Regulation of Programmed Cell Death of Developing Chick Embryo Spinal Cord Motoneurons
Authors: Ribera Joan , Ayala Victoria , Casas Celia
Published: April 2007

Key features of developmentally regulated programmed cell death (PCD) have been described for the first time in the chick nervous system. JNK/c-Jun pathway was involved in early events determining normal and pathological neuronal death as shown in experimental models. In the chick embryo, PCD of motoneurons (MNs) in ovo occurs within a well-defined temporal window and can be subjected to experimental manipulation. Taking advantage of this in vivo system, we explored the role of c-Jun and JNK pathway in the regulation of PCD in MNs. By using specific antibodies against phospho-c-Jun (Ser 63, 73) and JNK we demonstrated that before MNs acquire apoptotic phenotype there is an increase in c-Jun. Blockage of neuromuscular activity by the GABA agonist muscimol reduces PCD and diminishes c-Jun immunoreactivity in MNs. Extensive induction of PCD, either due to injection of β-bungarotoxin or limb bud removal, is also preceded by an increase in c-Jun immunoreactivity that is also associated with upregulation of phospho-c-Jun and JNK. Translocation of JNK from cytoplasm to MN nuclei was also detected. After acute application of β-bungarotoxin, which is a strong apoptotic stimulus for MNs, c-Jun phosphorylation occurs on serine 73, whereas serine 63 is the main site for c-Jun phosphorylation after limb bud removal. These results demonstrated that the JNK/c-Jun pathway is involved in the decision phase of normal and induced apoptosis in MNs. Pharmacological interventions involving this pathway should be explored as a potential therapeutic target for promoting MN survival.
Méthodes diagnostiques, caractéristiques cliniques et conseil dans la mucoviscidose
Authors: De Boeck Kris
Published: April 2007

Au cours des premiers mois de leur vie, la plupart des patients chez lesquels une mucoviscidose sera diagnostiquée présentent des manifestations cliniques classiques de cette maladie, telles qu’un iléus méconial, un retard de la croissance staturo-pondérale et une toux persistante ou récurrente. Ces troubles sont évidents et progressifs, et affectent différents appareils et organes. Chez ces patients, l’examen diagnostique standard est le test de la sueur. Une concentration des ions chlorure supérieure à 60 mmol/l dans la sueur confirme le diagnostic cliniquement suspecté. Depuis la découverte du gène CFTR (régulateur de la conductance transmembranaire de la mucoviscidose), il est devenu évident que le spectre clinique de cette maladie s’est élargi. Des mutations du gène CFTR ont été démontrées chez plusieurs catégories de patients: patients atteints d’une mucoviscidose classique, patients présentant des troubles moins sévères, patients chez lesquels la maladie est apparue au cours de l’adolescence ou même à l’âge adulte, ou patients présentant une caractéristique clinique isolée, par exemple pancréatite récurrente, cholangite sclérosante, bronchiectasies «idiopathiques» ou infertilité masculine. Ces deux dernières catégories ont été qualifiées de mucoviscidose atypique ou non classique. Il est très important que ces patients sachent qu’ils ne sont pas atteints d’une mucoviscidose classique, mais qu’il sont exposés au risque de maladie de type mucoviscidosique, ce qui justifie un suivi intermittent par des médecins connaissant bien le très large spectre de la maladie. Chez les patients présentant une mucoviscidose classique, des infections bactériennes sinusiennes et respiratoires chroniques et progressives avec exacerbations intermittentes sont les manifestations les plus typiques de la maladie. Une insuffisance pancréatique est présente chez 90% des patients. Les hommes sont stériles. Au cours de leur vie, les patients mucoviscidosiques peuvent présenter des manifestations pathologiques et des complications affectant les sinus, les poumons, le pancréas, le foie, l’intestin, l’œsophage, les os, les articulations, etc. Chaque patient est unique en raison de l’association complexe des manifestations possibles de la maladie. Le nombre des complications tend à s’accroître avec l’âge de ces patients, et leur état physique à s’aggraver. Une diminution de la tolérance à l’effort existe chez de nombreux adultes jeunes atteints d’une mucoviscidose en raison d’une atteinte respiratoire avancée; 20% présentent un diabète lié à la mucoviscidose. La mucoviscidose est une affection qui réduit l’espérance de vie et, même avec un traitement et un suivi des plus intensifs, la survie médiane actuelle est d’environ 34 ans, ce qui soumet les patients et leur famille à un stress psychologique extrêmement important. Les actions de conseil destinées à prévenir la réapparition de la maladie dans la fratrie et la famille étendue sont importantes et complexes.
Osirak Redux? Assessing Israeli Capabilities to Destroy Iranian Nuclear Facilities
Authors: Raas Whitney , Long Austin
Published: April 2007

Does Israel have the ability to conduct a military attack against Iran's nuclear facilities similar to its 1981 strike on Iraq's Osirak reactor? The Israeli Air Force has significantly upgraded its equipment since the early 1980s, but the Iranian nuclear complex is a much harder target than was the Osirak reactor. Iran has three facilities that are critical for nuclear weapons production: a uranium conversion facility, an enrichment facility, and a heavy-water production plant and associated plutonium production reactor. This article analyzes possible interactions of Israel's improved air force, including the addition of F-15I aircraft and U.S.-supplied conventional “bunker-buster” precision-guided munitions, with the Iranian target set and air defense systems. It concludes that Israel has the capability to attack Iran's nuclear infrastructure with at least as much confidence as it had in the 1981 Osirak strike. Beyond the case of Iran, this finding has implications for the use of precision-guided weapons as a counterproliferation tool. Precision-guided weapons confer the ability to reliably attack hard and deeply buried targets with conventional, rather than nuclear, weapons. Intelligence on the location of nuclear sites is thus the primary limiting factor of military counterproliferation.
“Is it Live, or is it Memorex?”
Authors: van der Laan J.M.
Published: April 2007

Our reception and perception, our experience of music, has been profoundly determined by our technological devices and media. Whatever music we happen to like and listen to, we can hardly experience it today apart from its production and reproduction in and through technology. The effects of technology on making and hearing music require critical analysis. Because of the pervasive role of technology, music today is almost entirely mediated and mediate, almost never unmediated and immediate, almost always “Memorex,” almost never “live.” Music has been severely altered, reduced, even hollowed out. In this respect, music loses something of its reality.
A Toolkit for Democratizing Science and Technology Policy: The Practical Mechanics of Organizing a Consensus Conference
Authors: Lee Kleinman Daniel , Powell Maria , Grice Joshua , Adrian Judith , Lobes Carol
Published: April 2007

A widely touted approach to involving laypeople in science and technology policy-related decisions is the consensus conference. Virtually nothing written on the topic provides detailed discussion of the many steps from citizen recruitment to citizen report. Little attention is paid to how and why the mechanics of the consensus conference process might influence the diversity of the participants in theses fora, the quality of the deliberation in the citizen sessions, the experiences of the participants and organizers, and other outcomes that affect democratic decision making within the conference and more broadly over the long term. As an aid to those interested in utilizing the consensus conference format, the authors outline in detail how they set about organizing their consensus conference on nanotechnology in the spring of 2005. They discuss what specific aspects of their consensus conference worked, and why, and also consider what they learned of relevance to future application.
The Endocannabinoid System and Neurogenesis in Health and Disease
Authors: Galve-Roperh Ismael , Aguado Tania , Palazuelos Javier , Guzmán Manuel
Published: April 2007

The endocannabinoid system exerts an important neuromodulatory function in different brain areas and is also known to be involved in the regulation of neural cell fate. Thus, CB1 cannabinoid receptors are neuroprotective in different models of brain injury, and their expression is altered in various neurodegenerative diseases. Recent findings have demonstrated the presence of a functional endocannabinoid system in neural progenitor cells that participates in the regulation of cell proliferation and differentiation. In this Research Update, the authors address the experimental evidence regarding the regulatory role of cannabinoids in neurogenesis and analyze them in the context of those pathological disorders in which cannabinoid function and altered neuronal or glial generation is most relevant, for example, stroke and multiple sclerosis. NEUROSCIENTIST 13(2):109—114, 2007.