bluuebunny/crossref_metadata_2025 huggingface dataset:
COMBINATORIAL CHARACTERIZATION OF THE LANGUAGE RECOGNIZED BY FACTOR AND SUFFIX ORACLES
Authors: MANCHERON ALBAN , MOAN CHRISTOPHE
Published: December 2005

Sequence Analysis requires to elaborate data structures, which allow both an efficient storage and use. A new one was introduced in 1999 by Cyril ALLAUZEN, Maxime CROCHEMORE and Mathieu RAFFINOT. This structure is linear on the size of the represented word both in time and space. It has the smallest number of states and it accepts at least all substrings of the represented word. This structure is called Factor Oracle. Authors developed another structure on the basis of Factor Oracle, which has the same properties except it accepts at least all suffixes instead of all factors of the represented word. This structure is then called Suffix Oracle. The characterization of the language recognized by the Factor/Suffix Oracle of a given word is an open problem, for which we provide a solution. Using this result, we show that these structures may accept an exponential number of words, which are not factors/suffixes of the given word.
CHRONOSEQUENCES OF STRONTIUM IN THE OTOLITHS OF TWO NEW ZEALAND MIGRATORY FRESHWATER FISH, INANGA (GALAXIAS MACULATUS) AND KOARO (G. BREVIPINNIS)
Authors: HICKS B. J. , WEST D. W. , BARRY B. J. , MARKWITZ A. , BAKER C. F. , MITCHELL C. P.
Published: November 2005

Half of the freshwater fish fauna in New Zealand is diadromous (i.e., migrates between the sea and freshwater); unimpeded access to and from the sea is important for the conservation of diadromous fish. The genus Galaxias (Galaxiidae: Osmeriformes) contains five diadromous species that spawn in freshwater, migrate to sea as larvae, and then migrate back into freshwater as 50-55-mm juveniles. Microchemistry of the otolith, a calcified structure in the fish's head, allows an independent test of assumptions about these migrations. Concentric layers of CaCO 3 with some Sr as SrCO 3 comprise the otolith, creating a chronosequence that reflects a fish's migratory history. More Sr accumulates in the otolith when a fish is in seawater than when it is in freshwater. High-resolution nuclear microscopy was used to measure the molar ratios of Sr/Ca in two galaxiid species. Otoliths of inanga (G. maculatus) caught in freshwater all showed a central zone of 100-200 μm in radius with Sr/Ca of 0.008-0.012, indicating early rearing in the sea. Sr/Ca values decreased to 0.001-0.002 as the fish moved into freshwater. Of six adult koaro (G. brevipinnis) caught in a river with sea access and no lakes, five had migrated to sea but one had not, raising questions about the generalized assumptions of migration.
MICRON-CT USING PIXE WITH MICRO-BEAMS
Authors: ISHII K. , MATSUYAMA S. , YAMAZAKI H. , WATANABE Y. , YAMAGUCHI T. , MOMOSE G. , AMAETAIVAN T. , SUZUKI A. , KIKUCHI Y. , GALSTER W.
Published: November 2005

We developed a micron-CT consisting of micro-beam system and X-ray CCD camera (Hamamatsu photonics C8800X), whose element size is 8μ m ×8μ m and a total number of image elements 1000×1000 gives an image size of 8 mm ×8 mm . The sample is placed in a tube of a small diameter, which is rotated by a stepping motor. The transmission data through the sample are taken with characteristic Ti - K -X-rays (4.558 keV) produced by 3MeV proton and α particle micro-beams. After image reconstruction using an iteration method, 3D-images of small objects namely, hair and small ants were obtained with a spatial resolution of ~5μm. It is expected that our micron-CT can provide cross sectional images of in-vivo cellular samples with high resolution and can be applied to a wide range of research in biology and medicine.
BIOMEDICAL IMAGING WITH THE LEIPZIG HIGH-ENERGY ION-NANOPROBE LIPSION
Authors: BUTZ T. , MEINECKE CH. , MENZEL F. , REINERT T. , SPEMANN D. , VOGT J. , TONG Y.
Published: November 2005

This contribution deals with the morphological and elemental characterisation of biomedical samples with high energy (MeV) focused ion beams with special emphasis on high spatial resolution in the sub-micrometer regime and very low minimum detection limits (< 50 μM/l) in trace element analysis. This paper gives an overview of recent applications at the LIPSION laboratory using PIXE (Particle Induced X-ray Emission) and STIM (Scanning Ion Transmission Microscopy) as well as STIM-Tomography.
PIXE MICROBEAM IN LOCALIZING METALS RELEASED FROM DENTAL AND ORTHOPEDIC IMPLANTS
Authors: PASSI PIETRO , ZADRO ANGELA , GALASSINI SILVIO , MOSCHINI GIULIANO , ROSSI PAOLO , SCAPINELLI RAFFAELE , CECCATO DANIELE , UZUNOV NIKOLAY
Published: November 2005

The release of metals and other elements from dental and orthopedic implants into the tissues has been a matter of numerous studies. However, the conditions that favor such a phenomenon have not been completely understood so far. PIXE microbeam technique has been applied to study the spatial distribution of the elements released from the implants. Subjects of interest have been implants made from commercially pure titanium, Ti -6 Al -4 V alloy and 316 LWM surgical steel. Block sections of five dental implants, as well as tissues surrounding one metal spine plate and two hip prostheses, have been examined. Rabbit bones containing copper inclusions have been taken for microbeam analysis to complete the study about the metal release processes. Samples from the tissues and bone slices have been analyzed using PIXE microbeam setup at National Laboratories of Legnaro, Italy. Traces of the implant metals, including titanium but with the exception of vanadium, were found in the surrounding tissues and maps of their elemental distribution at different distances from the contact surface with implants have been obtained. The origin and the differences of the release rate of the observed metals have been discussed.
AN OVERVIEW OF THE RCA/IAEA ACTIVITIES IN THE AUSTRALASIAN REGION USING NUCLEAR ANALYSIS TECHNIQUES FOR MONITORING AIR POLLUTION
Authors: MARKWITZ ANDREAS
Published: November 2005

The International Atomic Energy Agency (IAEA) via the Regional Co-operative Agreement (RCA) has identified air particulate matter pollution as a major transboundary environmental issue in the Australasian region. Sixteen countries in the region spanning from Pakistan to the Philippines and from China to New Zealand are participating in the regional programme "RAS/7/013– Improved information of urban air quality management in the RCA region" that started in 1997. New Zealand is the lead-country for this programme in which nuclear analytical techniques, such as particle induced X-ray emission (PIXE), neutron activation analysis (NAA) and X-ray fluorescence spectrometry (XRF) are used to measure key elements in PM 2.5-0 and PM 10-2.5 filters from GENT stacked samplers collected twice weekly. Major sources of air particulate matter pollution are identified using statistical source apportionment techniques. To identify transboundary air particulate matter pollution events, the data is collated in a large database. Additionally, the data is used by end-users of the participating countries in the programme. An overview is presented.
COMPUTER-AIDED SIMULATION AND IMPLEMENTATION OF V.90 MODULUS ENCODER
Authors: SINGH JASVIR , SHARMA DAVINDER PAL
Published: December 2005

This paper presents the computer-aided simulation and implementation of Modulus Encoder for V.90 digital modem transmitter, which is a device that performs Multiple Modulus Conversion (MMC) process. The present work deals with the development of an efficient algorithm for MMC process used by modulus encoder of V.90 digital modem transmitter, the corresponding assembly program development (source code generation), its simulation on simulator of Code Composer Studio and finally the implementation of modulus encoder on Digital Signal Processor (DSP). The practical results match with the simulated as well as theoretically predicted results, which confirms successful implementation of modulus encoder of V.90 digital modem transmitter on DSP. The implementation parameters like the total program execution time, data memory and program memory used for the present implementation have been presented.
ON THE DESIGN OF EFFICIENT MODULAR ADDERS
Authors: VERGOS HARIDIMOS T. , EFSTATHIOU CONSTANTINOS
Published: December 2005

Modular adders are met in various applications of computer systems. In this paper, we investigate a new architecture for their design that utilizes a carry save adder stage and two binary adders that operate in parallel. Realizations in static CMOS reveal that the introduced architecture leads to modular adder implementations that offer significant savings in delay and power consumption over implementations based on previously proposed architectures. In parallel, the proposed architecture offers significantly smaller implementation area for small operand widths.
THE ERROR MINIMIZATION OF DIGITAL FOURIER FILTER USED IN UNIPROCESSOR PROTECTIVE RELAYING FOR 6–33 kV ELECTRICAL NETWORKS
Authors: AL-ODIENAT ABDULLAH I. , RADAIDEH OMAR Y.
Published: December 2005

In this paper, a new method for error minimization of digital Fourier filter is proposed. The proposed method is tested by operating the electrical networks at oscillatory frequency. The functional features of microprocessor protective relaying and automatic switching devices are considered. The software structure of uniprocessor protective relaying and automatic switching equipments for the 6–33 kV lines are also presented.
A FPGA-BASED PARAMETRIZABLE SYSTEM FOR HIGH-RESOLUTION FREQUENCY-DOMAIN IMAGE FILTERING
Authors: UZUN ISA SERVAN , AMIRA ABBES
Published: December 2005

Signal and image processing applications require high computational power with the ability to experiment different algorithms involving matrix transforms. Reconfigurable hardware devices in the form of Field Programmable Gate Arrays (FPGAs) have been proposed to obtain high performance at an economical price. However, the users must program FPGAs at a very low level and must have a detailed knowledge of the architecture of the device being used. In trying to reconcile the dual requirements of high performance and the ease of development, this paper reports the design and realization of the Fast Fourier Transforms (FFTs) using a FPGA-based environment, which enables system designer to meet different system requirements (i.e., chip area, speed, memory, etc.) for a range of signal processing and imaging applications. The use of the proposed environment has been proven by the developing a high-level FPGA-based parametrizable image processing system for frequency-domain filtering application. The system achieves real-time image filtering performance exceeding those of currently available solutions by an order of magnitude in frame rate and input image size.
IMPLIED VOLATILITY TREES AND PRICING PERFORMANCE: EVIDENCE FROM THE S&P 100 OPTIONS
Authors: LINARAS CHARILAOS E. , SKIADOPOULOS GEORGE
Published: December 2005

This paper examines the pricing performance of various discrete-time option models that accept the variation of implied volatilities with respect to the strike price and the time-to-maturity of the option (implied volatility tree models). To this end, data from the S&P 100 options are employed for the first time. The complex implied volatility trees are compared to the standard Cox–Ross–Rubinstein model and the ad-hoc traders model. Various criteria and interpolation methods are used to evaluate the performance of the models. The results have important implications for the pricing accuracy of the models under scrutiny and their implementation.
ANALYTIC BACKWARD INDUCTION OF OPTION CASH FLOWS: A NEW APPLICATION PARADIGM FOR THE MARKOVIAN INTEREST RATE MODELS
Authors: GAN JUNWU
Published: December 2005

This paper develops a unified formulation and a new computational methodology for the entire class of the multi-factor Markovian interest rate models. The early exercise premium representation for general American options is derived for all Markovian models. The option cash flow functions are decomposed into fast and slowly varying components. The fast varying components have the same expression for all options within a model. They are calculated analytically. Only the slowly varying components are option specific. Their backward induction for a finite time interval is carried out from Taylor expansion expressions. The small coefficient of the expansion is the product of the variance and the width of the time interval. The option price is calculated by dividing its time horizon into smaller intervals and numerically iterating the Taylor expansion expressions of one time interval. Other new results include: (i) The derivation of a new "almost" Markovian LIBOR market model and its related Markovian short-rate model; (ii) the universal form of the critical boundary near the maturity for the American options in the one-factor Markovian models; and (iii) approximate analytic expressions for the entire critical boundary of the American put stock option. The put price calculated from the boundary has relative precision better than 10-5.
Roles for p21waf1/cip1 and p27kip1 during the adaptation response to massive intestinal resection
Authors: Stehr Wolfgang , Bernal Nicole P. , Erwin Christopher R. , Bernabe Kathryn Q. , Guo Jun , Warner Brad W.
Published: December 2005

The magnitude of gut adaptation is a decisive factor in determining whether patients are able to live independent of parenteral nutrition after massive small bowel loss. We previously established that the cyclin-dependent kinase inhibitor (CDKI) p21waf1/cip1 is necessary for enterocyte proliferation and a normal adaptation response. In the present study, we have further elucidated the role of this CDKI in the context of p27kip1, another member of the Cip/Kip CDKI family. Small bowel resections (SBRs) or sham operations were performed in control (C57/BL6), p21waf1/cip1-null, p27kip1-null, and p21waf1/cip1/p27kip1 double-null mice. Morphological (villus height/crypt depth) alterations in the mucosa, the kinetics of enterocyte turnover (rates of enterocyte proliferation and apoptosis), and the protein expression of various cell cycle-regulatory proteins were recorded at various postoperative times. Enterocyte compartment-specific mRNA expression was investigated using laser capture microdissection. Resection-induced adaptation in control mice coincided with increased protein expression of p21waf1/cip1 and decreased p27kip1 within 3 days postoperatively. Identical changes in mRNA expression were detected in crypt but not in villus enterocytes. Adaptation occurred normally in control and p27kip1-null mice; however, mice deficient in both p21waf1/cip1 and p27kip1 failed to increase baseline rates of enterocyte proliferation and adaptation. The expression of p21waf1/cip1 protein and mRNA in the proliferative crypt compartment is necessary for resection-induced enterocyte proliferation and adaptation. The finding that deficient expression of p27kip1 does not affect adaptation suggests that these similar CDKI family members display distinctive cellular functions during the complex process of intestinal adaptation.
Blunted nitric oxide-mediated inhibition of sympathetic nerve activity within the paraventricular nucleus in diabetic rats
Authors: Zheng Hong , Mayhan William G. , Bidasee Keshore R. , Patel Kaushik P.
Published: December 2005

Recent evidence suggests that a central mechanism may be contributing to the sympathetic abnormality in diabetes. Nitric oxide (NO) has been known as a neurotransmitter in the central nervous system. The goal of this study was to examine the role of the endogenous NO system of the paraventricular nucleus (PVN) in regulation of renal sympathetic nerve activity (RSNA) in streptozotocin (STZ)-induced diabetic rats. The change in number of NADPH-diaphorase-positive neurons [a marker for neuronal NO synthase (nNOS) activity] in the PVN was measured. Diabetic rats were found to have significantly fewer nNOS positive cells in the PVN than in the control group (120 ± 11 vs. 149 ± 13, P < 0.05). Using RT PCR, Western blotting and immunofluorescent staining, it was also found that nNOS mRNA expression and protein level in the PVN were significantly decreased in the diabetic rats. Furthermore, using an in vivo microdialysis technique, we found that there was a lower NOxrelease from the PVN perfusates in rats with diabetes compared with the control rats (142 ± 33 nM vs. 228 ± 29 nM, P < 0.05). In α-chloralose- and urethane-anesthetized rats, an inhibitor of NO synthase, l-NMMA, microinjected into the PVN produced a dose-dependent increase in RSNA, mean arterial pressure (MAP), and heart rate (HR) in both control and diabetic rats. These responses were significantly attenuated in rats with diabetes compared with control rats (RSNA: 11 ± 3% vs. 35 ± 3%, P < 0.05). On the other hand, an NO donor, sodium nitroprusside (SNP), microinjected into the PVN produced a dose-dependent decrease in RSNA, MAP, and HR in the control and diabetic rats. RSNA (17 ± 3%, vs. 41 ± 6%, P < 0.05) and MAP in response to SNP were significantly blunted in the diabetic group compared with the control group. In conclusion, these data indicate an altered NO mechanism in the PVN of diabetic rats. This altered mechanism may contribute to the increased renal sympathetic neural activity observed in diabetes.
Impaired endothelin-induced vasoconstriction in coronary arteries of Zucker obese rats is associated with uncoupling of [Ca2+]isignaling
Authors: Katakam Prasad V. G. , Snipes James A. , Tulbert Christina D. , Mayanagi Keita , Miller Allison W. , Busija David W.
Published: December 2005

Although insulin resistance (IR) is a major risk factor for coronary artery disease, little is known about the regulation of coronary vascular tone in IR by endothelin-1 (ET-1). We examined ET-1 and PGF2α-induced vasoconstriction in isolated small coronary arteries (SCAs; ∼250 μM) of Zucker obese (ZO) rats and control Zucker lean (ZL) rats. ET-1 response was assessed in the absence and presence of endothelin type A (ETA; BQ-123), type B (ETB; BQ-788), or both receptor inhibitors. ZO arteries displayed reduced contraction to ET-1 compared with ZL arteries. In contrast, PGF2αelicited similar vasoconstriction in both groups. ETAinhibition diminished the ET-1 response in both groups. ETBinhibition alone or in combination with ETAblockade, however, restored the ET-1 response in ZO arteries to the level of ZL arteries. Similarly, inhibition of endothelial nitric oxide (NO) synthase with Nω-nitro-l-arginine methyl ester (l-NAME) enhanced the contraction to ET-1 and abolished the difference between ZO and ZL arteries. In vascular smooth muscle cells from ZO, ET-1-induced elevation of myoplasmic intracellular free calcium concentration ([Ca2+]i) (measured by fluo-4 AM fluorescence), and maximal contractions were diminished compared with ZL, both in the presence and absence of l-NAME. However, increases in [Ca2+]ielicited similar contractions of the vascular smooth muscle cells in both groups. Analysis of protein and total RNA from SCA of ZO and ZL revealed equal expression of ET-1 and the ETAand ETBreceptors. Thus coronary arteries from ZO rats exhibit reduced ET-1-induced vasoconstriction resulting from increased ETB-mediated generation of NO and diminished elevation of myoplasmic [Ca2+]i.
Role for pituitary adenylate cyclase activating polypeptide in cystitis-induced plasticity of micturition reflexes
Authors: Braas Karen M. , May Victor , Zvara Peter , Nausch Bernhard , Kliment Jan , Dunleavy J. Dana , Nelson Mark T. , Vizzard Margaret A.
Published: December 2005

Pituitary adenylate cyclase activating polypeptide (PACAP) peptides are expressed and regulated in sensory afferents of the micturition pathway. Although these studies have implicated PACAP in bladder control, the physiological significance of these observations has not been firmly established. To clarify these issues, the roles of PACAP and PACAP signaling in micturition and cystitis were examined in receptor characterization and physiological assays. PACAP receptors were identified in various tissues of the micturition pathway, including bladder detrusor smooth muscle and urothelium. Bladder smooth muscle expressed heterogeneously PAC1null, PAC1HOP1, and VPAC2receptors; the urothelium was more restricted in expressing preferentially the PAC1receptor subtype only. Immunocytochemical studies for PAC1receptors were consistent with these tissue distributions. Furthermore, the addition of 50–100 nM PACAP27 or PACAP38 to isolated bladder strips elicited transient contractions and sustained increases in the amplitude of spontaneous phasic contractions. Treatment of the bladder strips with tetrodotoxin (1 μM) did not alter the spontaneous phasic contractions suggesting direct PACAP effects on bladder smooth muscle. PACAP also increased the amplitude of nerve-evoked contractions. By contrast, vasoactive intestinal polypeptide had no direct effects on bladder smooth muscle. In a rat cyclophosphamide (CYP)-induced cystitis paradigm, intrathecal or intravesical administration of PAC1receptor antagonist, PACAP6–38, reduced cystitis-induced bladder overactivity. In summary, these studies support roles for PACAP in micturition and suggest that inflammation-induced plasticity in PACAP expression in peripheral and central micturition pathways contribute to bladder dysfunction with cystitis.
Effects of a reduction in maternal renal mass on pregnancy and cardiovascular and renal function of the pregnant ewe
Authors: Gibson Karen J. , Thomson Clare L. , Boyce Amanda C. , Karime Bilal M. , Lumbers Eugenie R.
Published: November 2005

Maternal renal disease is associated with high maternal and fetal morbidity. To establish an animal model to study renal dysfunction in pregnancy and its potential role in programming for renal disease and hypertension in adult life, a kidney was removed from each of 16 nonpregnant ewes, and a branch of the renal artery of the remaining kidney was ligated (STNx ewes). The 16 STNx and 15 intact ewes were time mated 2.5–17 mo later and studied at 119–132 days of gestation. STNx ewes demonstrated renal hypertrophy and glomerular hyperfiltration. They had higher diastolic arterial pressures ( P < 0.05) and larger left ventricles ( P < 0.0005), drank more water ( P < 0.01), were hypochloremic ( P < 0.01) and hyperglycemic ( P < 0.0005), and had higher plasma creatinine levels ( P < 0.0005) than intact ewes. Effective renal plasma flows and glomerular filtration rates were lower ( P < 0.01) and protein excretion was greater ( P < 0.05) in STNx than in intact ewes. Glomerulotubular balance was impaired in STNx ewes. Proximal tubular Na+reabsorption was reduced ( P < 0.05), so Na+excretion was increased ( P < 0.05). In STNx ewes, filtered K+loads were reduced ( P < 0.005), but K+excretion was the same as in intact ewes. There was net K+secretion in STNx ewes; in intact ewes, there was net reabsorption. Plasma renin and angiotensinogen concentrations in STNx and intact ewes were similar, so the hypertension in STNx ewes was not renin dependent. STNx fetuses grew normally, and their blood gases, blood pressure, and heart rates were normal. These alterations in maternal fluid and electrolyte balance and the potential risk of maternal salt depletion or hyperkalemia may adversely affect the fetus.
Aging augments interstitial K+concentrations in active muscle of rats
Authors: Li Jianhua , Sinoway Lawrence I. , Ng Yuk-Chow
Published: December 2005

Skeletal muscle performance declines with advancing age, and the underlying mechanism is not completely understood. A large body of convincing evidence has demonstrated a crucial role for interstitial K+concentration ([K+]o) in modulating contractile function of skeletal muscle. The present study tested the hypothesis that during muscle contraction there is a greater accumulation of [K+]oin aged compared with adult skeletal muscle. Twitch muscle contraction was induced by electrical stimulation of the sciatic nerves of 8- and 32-mo-old Fischer 344 × Brown Norway rats. Levels of [K+]owere measured continuously by a microdialysis technique with the probes inserted into the gastrocnemius muscle. Stimulation at 1, 3, and 5 Hz elevated muscle [K+]oby 52, 64, and 88% in adult rats, and by 78, 98, and 104% in aged rats, respectively, and the increase was significantly higher in aged than in adult rats. Recovery for [K+]o, as measured by the time for [K+]oto recover by 20 and 50% from peak response after stimulation, was slower in aged rats. Ouabain (5 mM), a specific inhibitor of the Na+-K+pump, was added in the perfusate to inhibit the reuptake of K+into the cells to assess the role of the pump in the overall K+balance. Ouabain elevated muscle [K+]oat rest, and the effect was significantly attenuated in aged animals. The present data demonstrated an augmented [K+]oin aged skeletal muscle compared with adult skeletal muscle, and the data suggested that an alteration in the function of the Na+-K+pump may contribute, in part, to the deficiency in K+balance in skeletal muscle of aged rats.
Exogenous carbohydrate oxidation during ultraendurance exercise
Authors: Jeukendrup Asker E. , Moseley Luke , Mainwaring Gareth I. , Samuels Spencer , Perry Samuel , Mann Christopher H.
Published: December 2005

The purposes of this study were: 1) to obtain a measure of exogenous carbohydrate (CHOExo) oxidation and plasma glucose kinetics during 5 h of exercise; and 2) to compare CHOExo following the ingestion of a glucose solution (Glu) or a glucose + fructose solution (2:1 ratio, Glu+Fru) during ultraendurance exercise. Eight well-trained subjects exercised three times for 5 h at 58% maximum O2 consumption while ingesting either Glu or Glu+Fru (both delivering 1.5 g/min CHO) or water. The CHO used had a naturally high 13C enrichment, and five subjects received a primed continuous intravenous [6,6-2H2]glucose infusion. CHOExo rates following the ingestion of Glu leveled off after 120 min and peaked at 1.24 ± 0.04 g/min. The ingestion of Glu+Fru resulted in a significantly higher peak rate of CHOExo (1.40 ± 0.08 g/min), a faster rate of increase in CHOExo, and an increase in the percentage of CHOExo oxidized (65–77%). However, the rate of appearance and disappearance of Glu continued to increase during exercise, with no differences between trials. These data suggest an important role for gluconeogenesis during the later stages of exercise. Following the ingestion of Glu+Fru, cadence (rpm) was maintained, and the perception of stomach fullness was reduced relative to Glu. The ingestion of Glu+Fru increases CHOExo compared with the ingestion of Glu alone, potentially through the oxidation of CHOExo in the liver or through the conversion to, and oxidation of, lactate.
Circulatory galanin levels increase severalfold with intense orthostatic challenge in healthy humans
Authors: Hinghofer-Szalkay Helmut G. , Rössler Andreas , Evans Joyce M. , Stenger Michael B. , Moore Fritz B. , Knapp Charles F.
Published: December 2005

The purpose of this study was to test the hypothesis that plasma galanin concentration (pGal) is regularly increased in healthy humans with extensive orthostatic stress. Twenty-six test persons (14 men, 12 women) were brought to an orthostatic end point via a progressive cardiovascular stress (PCS) protocol consisting of 70° head-up tilt plus increasing levels of lower body negative pressure until either hemodynamically defined presyncope or other signs of orthostatic intolerance occurred (nausea, clammy skin, excessive sweating, pallor of the skin). We further tested for possible gender, gravitational, and muscular training influences on plasma pGal responses: PCS was applied before and after 3 wk of daily vertical acceleration exposure training on a Human Powered Centrifuge. Test persons were randomly assigned to active (with bicycle work) or passive (without work) groups (seven men, six women in each group). Resting pGal was 26 ± 3 pg/ml in men and 39 ± 15 pg/ml in women (not significant); women had higher galanin responses (4.9-fold increase) than men (3.5-fold, P = 0.017) to PCS exposure. Overall, PCS increased pGal to 186 ± 5 pg/ml ( P = 0.0003), without significant differences between presyncope vs. orthostatic intolerance, pre- vs. postcentrifuge, or active vs. passive gravitational training. Increases in pGal were poorly related to synchronous elevations in plasma vasopressin. We conclude that galanin is regularly increased in healthy humans under conditions of presyncopal orthostatic stress, the response being independent of gravity training but larger in women than in men.
Effects of endurance exercise training on heart rate variability and susceptibility to sudden cardiac death: protection is not due to enhanced cardiac vagal regulation
Authors: Billman George E. , Kukielka Monica
Published: December 2005

Low heart rate variability (HRV) is associated with an increased susceptibility to ventricular fibrillation (VF). Exercise training can increase HRV (an index of cardiac vagal regulation) and could, thereby, decrease the risk for VF. To test this hypothesis, a 2-min coronary occlusion was made during the last min of a 18-min submaximal exercise test in dogs with healed myocardial infarctions; 20 had VF (susceptible), and 13 did not (resistant). The dogs then received either a 10-wk exercise program (susceptible, n = 9; resistant, n = 8) or an equivalent sedentary period (susceptible, n = 11; resistant, n = 5). HRV was evaluated at rest, during exercise, and during a 2-min occlusion at rest and before and after the 10-wk period. Pretraining, the occlusion provoked significantly ( P < 0.01) greater increases in HR (susceptible, 54.9 ± 8.3 vs. resistant, 25.0 ± 6.1 beats/min) and greater reductions in HRV (susceptible, −6.3 ± 0.3 vs. resistant, −2.8 ± 0.8 ln ms2) in the susceptible dogs compared with the resistant animals. Similar response differences between susceptible and resistant dogs were noted during submaximal exercise. Training significantly reduced the HR and HRV responses to the occlusion (HR, 17.9 ± 11.5 beats/min; HRV, −1.2 ± 0.8, ln ms2) in the susceptible dogs; similar response reductions were noted during exercise. In contrast, these variables were not altered in the sedentary susceptible dogs. Posttraining, VF could no longer be induced in the susceptible dogs, whereas four sedentary susceptible dogs died during the 10-wk control period, and the remaining seven animals still had VF when tested. Atropine decreased HRV but only induced VF in one of eight trained susceptible dogs. Thus exercise training increased cardiac vagal activity, which was not solely responsible for the training-induced VF protection.
Which Visual Pathways Cause Fixation-Related Inhibition?
Authors: Sumner Petroc , Nachev Parashkev , Castor-Perry Sarah , Isenman Heather , Kennard Christopher
Published: November 2005

Visual stimuli can both inhibit and activate motor mechanisms. In one well-known example, the latency of saccadic eye movements is prolonged in the presence of a fixation stimulus, relative to the case in which the fixation stimulus disappears before the target appears. This automatic sensory-motor effect, known as the gap effect or fixation-offset effect, has been associated with inhibitory connections within the superior colliculus (SC). Visual information is provided to the SC and other oculomotor areas, such as the frontal eye fields (FEF), mainly by the magnocellular geniculostriate pathway, and also by the retinotectal pathway. We tested whether signals in these pathways are necessary to create fixation-related inhibition, by using stimuli invisible to them. We found that such stimuli, visible only to short-wave–sensitive cones (S cones), do produce fixation-related inhibition (including when warning effects were equated). We also demonstrate that this fixation-related inhibition cannot be explained by residual activation of luminance pathways and must be caused by a route separate from that of luminance fixation signals. Thus there are at least two routes that cause fixation-related inhibition, and direct sensory input to the SC or FEF by the magnocellular or retinotectal pathways is not required. We discuss the implications that there may be both cortical and collicular mechanisms.
Partial Cross-Correlation Analysis Resolves Ambiguity in the Encoding of Multiple Movement Features
Authors: Stark Eran , Drori Rotem , Abeles Moshe
Published: November 2005

A classical question in neuroscience is which features of a stimulus or of an action are represented in brain activity. When several features are interdependent either at a given point in time or at distinct points in time, neural activity related to one feature appears to be correlated with other features. Thus techniques that simultaneously consider multiple features cannot account for delayed interdependencies between features. The result is an ambiguity with respect to the encoded features. Here, we resolve this ambiguity by applying a novel statistical method based on partial cross-correlations. The method yields estimates of linear correlations between neural activity and a given feature that are not affected by linear correlations with other features at multiple time delays. The method also provides a graphical output measured on a scale that allows for comparisons between different features, neurons, and experiments. We use real movement data and neural activity simulated according to a wide range of tuning models to illustrate the method. When applied to real neural activity, the procedure yields results that indicate which of the considered features the neural activity is related to and at what time delays.
Identification and characterization of a novel member of the ATP-sensitive K+channel subunit family, Kir6.3, in zebrafish
Authors: Zhang Changliang , Miki Takashi , Shibasaki Tadao , Yokokura Masaaki , Saraya Atsunori , Seino Susumu
Published: November 2005

ATP-sensitive K+(KATP) channels play a crucial role in coupling cellular metabolism to membrane potential. In addition to the orthologs corresponding to Kir6.1 and Kir6.2 of mammals, we have identified a novel member, designated Kir6.3 (zKir6.3), of the inward rectifier K+channel subfamily Kir6.x in zebrafish. zKir6.3 is a protein of 432 amino acids that shares 66% identity with mammalian Kir6.2 but differs considerably from mammalian Kir6.1 and Kir6.2 in the COOH terminus, which contain an Arg-Lys-Arg (RKR) motif, an endoplasmic reticulum (ER) retention signal. Single-channel recordings of reconstituted channels show that zKir6.3 requires the sulfonylurea receptor 1 (SUR1) subunit to produce KATPchannel currents with single-channel conductance of 57.5 pS. Confocal microscopic analysis shows that zebrafish Kir6.3 requires the SUR1 subunit for its trafficking to the plasma membrane. Analyses of chimeric protein between human Kir6.2 and zKir6.3 and a COOH-terminal deletion of zKir6.3 indicate that interaction between the COOH terminus of zKir6.3 and SUR1 is critical for both channel activity and trafficking to the plasma membrane. We also identified zebrafish orthologs corresponding to mammalian SUR1 (zSUR1) and SUR2 (zSUR2) by the genomic database. Both Kir6.3 and SUR1 are expressed in embryonic brain of zebrafish, as assessed by whole mount in situ hybridization. These data indicate that Kir6.3 and SUR1 form functional KATPchannels at the plasma membrane in zebrafish through a mechanism independent from ER retention by the RKR motif.
Evaluation of Right Ventricular Function in Patients with Thyroid Dysfunction
Authors: Arinc Huseyin , Gunduz Huseyin , Tamer Ali , Seyfeli Ergun , Kanat Mustafa , Ozhan Hakan , Akdemir Ramazan , Celebi Harika , Uyan Cihangir
Published: November 2005

Background: Thyroid gland dysfunction affects the structure and function of the heart. Tissue Doppler echocardiography is a new technique, and it has been used frequently in the evaluation of ventricular function. In the present study, right ventricular function was assessed in patients with overt or subclinical hypothyroidism and hyperthyroidism and in healthy subjects using the tissue Doppler method, and results were compared. Patients and Methods: 20 healthy subjects and 63 patients diagnosed with overt and subclinical hypothyroidism and hyperthyroidism were included in the study. Annular and myocardial systolic peak velocities, early and late diastolic peak velocities, precontraction, total contraction and relaxation times of the right ventricle were recorded by tissue Doppler echocardiography. The results of the patients were compared to those of the controls. Results: Myocardial systolic velocity was significantly higher in patients with hyperthyroidism. Annular and myocardial late diastolic velocities were found to be significantly lower in patients with overt hypothyroidism. Annular precontraction time was increased in patients with overt and subclinical hypothyroidism. Myocardial precontraction time was decreased in patients with hyperthyroidism, and increased in patients with overt hypothyroidism patients. Annular relaxation time was increased in patients with overt hypothyroidism. Conclusions: Right ventricular function is affected in patients with thyroid diseases. The tissue Doppler technique is a suitable tool to detect impairments in right ventricular function. There is a significant correlation between serum thyroid hormone levels and right ventricular velocities and time intervals.
Expression of Matrix Metalloproteinases 2, 7 and 9, and Their Tissue Inhibitors 1 and 2, in Developing Rabbit Tracheae
Authors: Miller Thomas L. , Touch Suzanne M. , Singhaus Clifford J. , Ramesh Babu Polani B. , Chidekel Aaron , Shaffer Thomas H.
Published: November 2005

Background: Structural changes in the developing conducting airway impact the rigidity of the airway, altering the airway’s ability to sustain its shape during ventilation. The developmental changes in airway compliance oppose the changes in compliance of the developing lung; thus the expression profiles of matrix modeling proteins likely are also opposite in these developing organs. Objectives: To determine the profiles of matrix metalloproteinases (MMPs) -2, -7, and -9 and tissue inhibitors (TIMPs) -1 and -2 in the developing trachea and test the hypothesis these profiles would contrast those previously reported for the lung. Methods: Rabbits tracheae were harvested at 21 days of gestation, 3 and 17 days postgestation and at adulthood. Tissue homogenates were analyzed by substrate zymography for the activity of MMPs, and reverse zymography for TIMPs. Immunostainings on neonatal lamb tracheal rings were used to localize MMP-2 and 9. Results: Analysis revealed an age-dependent decrease in total MMP-2 quantity and the ratio of active to latent forms. TIMP-2 shows a time-dependent increase throughout airway development. Total MMP-9 and TIMP-1 quantities were unchanged across these ages, although MMP-9 protein was found predominantly in its latent form during development and predominantly in its active form during adulthood. Respiratory epithelial cells reacted positive for both MMP-2 and 9 and trachealis muscle fibers were positive for MMP-2. No MMP-7 expression was identified in the rabbit airway. Conclusions: The opposing developmental patterns in MMP-2 expression between the airway and lung lead to speculation regarding the role of MMP-2 activity on changes in organ compliance.
Risk Factors Regarding the Need for a Second Operation in Patients with Crohn’s Disease
Authors: Avidan B. , Sakhnini E. , Lahat A. , Lang A. , Koler M. , Zmora O. , Bar-Meir S. , Chowers Y.
Published: November 2005

Background/Aims: The majority of Crohn’s disease patients undergo surgery. However, the factors that predict post-operative recurrence remain controversial. The aim of the present study was to shed light on the potential predictors of such recurrence. Methods: 86 patients who underwent operative procedures for Crohn’s disease were retrospectively studied. Recurrence was defined as the need for a second operation. Life table and multivariate analysis were performed to find the predictors of recurrence. Results: In 26/86 (30%) of the patients, post-operative recurrence was diagnosed within a mean of 42 months of the follow-up. Logistic regression analysis revealed that smoking (OR 3.69, 95% CI 2.06–11.52) and perforating disease (OR 4.09, 95% CI 1.31–12.65) were associated with a risk of recurrence. However, survival analysis showed that only perforating disease was associated with an early post-operative recurrence (log-rank test, p < 0.001). Neither resected surgical specimen characteristics, nor the duration and the location of the disease were found to predict the need for a second operation. Conclusion: The risk for Crohn’s disease patients who undergo surgery is related to the presence of perforating disease and smoking, which predict the need for a second operation. The former is associated with an even earlier recurrence.
Genome Diversity: A Grammar of Microbial Genomes
Authors: Danchin Antoine
Published: November 2005

The metaphor of the genetic program is ubiquitously used. Does it bring about a deeper insight into what cells are? In brief, computers do not make computers, but cells make cells. Pursuing the analogy in its deepest consequences we explore bacterial genome diversity as organized around core programs meant to couple the expression of the program with the architecture of the cell. At first sight genomes appear to evolve fast and exhibit no rule of organization. However, when the huge number of generations separating various organisms is taken into account, diversity appears only as a trivial observation. In contrast, rules of gene organization are observed, for example in the separation between Archaea and Bacteria, in the composition of the leading and lagging strand of the chromosomes, in the distribution of genes along the DNA strands, or in the formation (and conservation) of operons and pathogenicity islands.
Challenges in Genome-Wide Transcription Analysis when Using Microarrays for Non-Model Bacteria
Authors: Francois Patrice , Schrenzel Jacques
Published: November 2005

Recent advances in both technology and molecular biology have opened the way to the development of high-throughput techniques. DNA microarrays benefited from these determinant efforts and are now becoming conventional methods. Surprisingly, the most complicated organisms (i.e. eukaryotes) were the first targets of microarray-based experiments. Completion of sequencing projects for numerous bacterial genomes has recently enabled the design of non-model prokaryotic microarrays. Several important social fields will benefit from transcriptomic analysis of bacteria, such as human and veterinarian medicine, the food industry, or bioremediation. This review presents the current status of microbial studies using microarrays and describes limitations and caveats encountered in microarray design, experimental techniques, exploration and analysis of large data sets, as well as nomenclature issues that currently challenge microarray users.
Quorum Sensing: The Complexities of Chemical Communication between Bacteria
Authors: Barnard Anne M.L. , Salmond George P.C.
Published: November 2005

It is becoming increasingly clear that bacteria are able to communicate with each other to regulate gene expression in a concerted way, dependent upon the population density, by a process termed ‘quorum sensing’ (QS). Here we review N-acyl homoserine lactone-mediated QS in Gram-negative bacteria, and, in particular, its importance in vivo, in pathogenicity and virulence. We also describe systems that have been developed by other organisms to either exploit or interfere with bacterial QS.
Phase I and Pharmacokinetic Study of S-1 Combined with Weekly Paclitaxel in Patients with Advanced Gastric Cancer
Authors: Fujitani Kazumasa , Narahara Hiroyuki , Takiuchi Hiroya , Tsujinaka Toshimasa , Satomi Eriko , Gotoh Masahiro , Hirao Motohiro , Furukawa Hiroshi , Taguchi Tetsuo
Published: November 2005

Objective: A dose-escalation study of weekly paclitaxel combined with S-1, a novel oral fluoropyrimidine, was performed to determine the maximum tolerated dose (MTD), the recommended dose (RD) and the dose-limiting toxicities (DLTs) in advanced gastric cancer. Patients and Methods: Twelve patients were enrolled. S-1 was given orally at a fixed dosage of 40 mg/m2 b.i.d. for 14 consecutive days, followed by a 1-week rest. Paclitaxel was scheduled to be given intravenously on days 1 and 8 at a dose of 50, 60, 70 or 80 mg/m2, depending on the DLTs. Treatment was repeated every 3 weeks. A pharmacokinetic study was conducted in an additional 5 patients on days 7 and 8 during the first course given at the RD. Results: The MTD of paclitaxel was presumed to be 60 mg/m2, because 50.0% of patients (2/4) developed DLTs (mainly grade 3 anorexia). DLT was observed in 1 out of 8 patients at a dose of 50 mg/m2. Therefore, the RD of paclitaxel was estimated to be 50 mg/m2. The preliminary response rate was 62.5% (5/8) at the RD. There were no significant pharmacokinetic interactions between S-1 and paclitaxel. An adequate plasma paclitaxel concentration for an antineoplastic effect was achieved with weekly doses of 50 mg/m2. Conclusion: Weekly paclitaxel combined with S-1 was demonstrated to exhibit a tolerable toxicity profile with therapeutic plasma concentration at the dose of 50 mg/m2. This regimen could represent a novel and low toxic combination for advanced gastric cancer.
Flow Diversion in Transcranial Doppler Ultrasound Is Associated with Better Improvement in Patients with Acute Middle Cerebral Artery Occlusion
Authors: Kim Yo Sik , Meyer John Stirling , Garami Zsolt , Molina Carlos A. , Pavlovic Aleksandra M. , Alexandrov Andrei V.
Published: November 2005

Backgound: Flow diversion (FD) can occur with an acute middle cerebral artery (MCA) occlusion. FD is thought to represent the collateral blood flow to the occluded MCA territory, but it is unclear whether or not FD lessens the stroke severity or leads to improved outcome. Methods: Patients with a proximal MCA occlusion were selected from the CLOTBUST trial data bank. FD to the anterior or posterior cerebral artery was determined using transcranial Doppler ultrasound. Stroke severity and clinical improvement were measured using the National Institutes of Health Stroke Scale (NIHSS) scores. Results: We evaluated 47 patients with an isolated M1 MCA occlusion who received intravenous tissue-type plasminogen activator (t-PA) within 3 h of symptom onset. FD was present in 83% of the patients. Median baseline NIHSS scores were 15.5 in the FD– group and 18 in the FD+ group (n.s.). Complete recanalization rates were 25 and 25.6% (n.s.). In 35 patients with a persistent occlusion, the average NIHSS score reduction was 22% (FD+) and 0.52% (FD–) during 90 min after t-PA bolus (p = 0.017), and 29 versus –25% during the first 24 h after the t-PA bolus, respectively (p = 0.01). Conclusions: In patients with persistent MCA occlusions after thrombolytic treatment, arterial blood flow diversion is associated with earlier and better neurological improvement. FD has protective effects on the ischemic brain tissue with persistent MCA occlusion.