bluuebunny/crossref_metadata_2025 huggingface dataset:
Telomere‐independent cellular senescence in human fetal cardiomyocytes
Authors: Ball Andrew J. , Levine Fred
Published: January 2005

Fetal cardiomyocytes have been proposed as a potential source of cell‐based therapy for heart failure. This study examined cellular senescence in cultured human fetal ventricular cardiomyocytes (HFCs). HFCs were isolated and identified by immunocytochemistry and RT‐PCR. Cells were found to senesce after 20–25 population doublings, as determined by growth arrest, morphological changes and senescence‐associated β‐galactosidase activity. Using the telomeric repeat amplification protocol assay, telomerase activity was undetectable in primary HFCs. Cells were transduced to express the human reverse transcriptase subunit (hTERT) of telomerase. This resulted in greatly increased telomerase activity, but no significant lifespan extension. Analysis of telomere length in primary HFCs revealed that the senescent phenotype was not accompanied by telomere shortening. Telomeres in hTERT‐positive cells were elongated in comparison with primary cells, and elongation was retained in senescent cells. Levels of the tumor suppressor protein p16INK4A increased in all senescent cells whether telomerase‐positive or ‐negative. Senescence was accompanied by a decline in transcript levels of the polycomb gene Bmi‐1, Ets1 and Ets2 transcription factors, and Id1, Id2 and Id3 helix–loop–helix proteins, suggesting roles for these genes in maintenance of cardiomyocyte proliferative capacity. In addition to offering novel insights into the behavior of human fetal cardiomyocytes in culture, these findings have implications for the development of a cell‐based therapy for cardiac injury using primary fetal heart tissue.
Stochastic dietary restriction using a Markov‐chain feeding protocol elicits complex, life history response in medflies
Authors: Carey James R. , Liedo Pablo , Müller Hans‐Georg , Wang Jane‐Ling , Zhang Ying , Harshman Lawrence
Published: January 2005

Lifespan in individually housed medflies (virgins of both sexes) and daily reproduction for females were studied following one of 12 dietary restriction (DR) treatments in which the availability of high‐quality food (yeast–sugar mixture) for each fly was based on a Markov chain feeding scheme – a stochastic dietary regime which specifies that the future dietary state depends only on the present dietary state and not on the path by which the present state was achieved. The stochastic treatments consisted of a combination of one of four values of a ‘discovery’ parameter and one of three values of a ‘persistence’ parameter. The results supported the hypotheses that: (i) longevity is extended in most medfly cohorts subject to stochastic DR; and (ii) longevity is more affected by the patch discovery than the patch persistence parameter. One of the main conclusions of the study is that, in combination with the results of earlier dietary restriction studies on the medfly, the results reinforce the concept that the details of the dietary restriction protocols have a profound impact on the sign and magnitude of the longevity extension relative to ad libitum cohorts and that a deeper understanding of the effect of food restriction on longevity is not possible without an understanding of its effect on reproduction.
Genetic Factors in Type 2 Diabetes: The End of the Beginning?
Authors: O'Rahilly Stephen , Barroso Inês , Wareham Nicholas J.
Published: January 2005

The intensive search for genetic variants that predispose to type 2 diabetes was launched with optimism, but progress has been slower than was hoped. Even so, major advances have been made in the understanding of monogenic forms of the disease which together represent a substantial health burden, and a few common gene variants that influence susceptibility have now been unequivocally identified. Armed with a better understanding of the tools needed to detect such genes, it seems inevitable that the rate of progress will increase and the relevance of genetic information to the diagnosis, treatment, and prevention of diabetes will become increasingly tangible.
INTRODUCTION BY GUEST EDITORS
Authors: GEDEON TAMÁS D.
Published: January 2005

The information technology revolution threatens to swamp us in vast amounts of electronic data. Novel computing techniques based on notions gleaned from the information processing capabilities of biological neural systems provide some hope. The common themes are the compression of information into compact higher order forms. This can also be called automated knowledge or information extraction. The development of systems or components of systems to perform such tasks is becoming increasingly important.
The ER Behavior of Surface Modified Complex Strontium Titanate Suspensions
Authors: Zhang Yuling , Zhang Shaohua , Lu Kunquan
Published: January 2005

The ER behavior of the water-free complex strontium titanate(STO) particles, which were synthesized by means of sol-gel technique with surface modification dispersed in silicone oil, was investigated systematically. It is found that this fluid has attractive ER properties with high shear stress, low leakage current, wide dynamic range in both temperature and shear rate, as well as good antisettling character.
SYNTHESIS AND ELECTRORHEOLOGICAL CHARACTERIZATION OF POLYANILINE AND NA+-MONTMORILLONITE CLAY NANOCOMPOSITE
Authors: KIM J. W. , KIM S. G. , CHOI H. J. , SUH M. S. , SHIN M. J. , JHON M. J.
Published: January 2005

Polyaniline- Na +-montmorillonite nanocomposite particles were synthesized using an emulsion intercalation method, and electrorheological (ER) fluids were produced by dispersing the synthesized nanocomposite particles in an electrically-insulating silicone oil. The emulsion of an aniline monomer with dodecyl benzenesulfonic acid was inserted into the layers of clay, and polymerization was processed by adding the oxidant initiator solution. DBSA as a emulsifier and a dopant took a important role for polyaniline clay nanocomposite. This insertion of polyaniline was confirmed by X-ray diffraction. To observe its ER properties, we measured the shear viscosity and the shear stress by controlling shear rate. Furthermore, we conducted dynamic tests to investigate the viscoelastic properties of the ER fluid under an electric field in the linear viscoelastic region.
CONVERGING AND DIVERGING FLOW OF ELECTRORHEOLOGICAL FLUID IN MINUTE CHANNELS
Authors: NARUMI TAKATSUNE , HAYASHIBE TAKASHI , HASEGAWA TOMIICHI , ASAKO YOSHINOBU
Published: January 2005

We have examined ER effects in very small parallel and non-parallel gaps utilizing conventional ER suspensions. The flow rate reduction due to the electric field applied is measured as the ER effect for parallel, converging, diverging and combined channels. The test with the parallel channel under AC or rectangular pulse wave electric fields shows that the ER fluids are helpful for the flow rate control even in a narrow gap with the size about 10 times of particle diameter. In comparison between a converging channel and a diverging one, the former has advantages in magnitude and stability of ER effect. Moreover, the converging channel generates larger ER effect than that of the parallel channel with same flow characteristics under no electric field. It is considered that a small area with a higher electric field in the non-parallel channel makes it easy to control the flow rate. Further, the multiplier effect of the converging flow of particles and the increase in electric field along the flow direction generates a larger and stable ER effect. We have also examined with a combined converging and diverging channel and confirmed the similar enhancement in ER effect to the single converging one without the unsymmetrical ER effect due to the flow direction.
DOMAIN STRUCTURE AND MR EFFECT OF FERROFLUID EMULSION
Authors: OGAWA CHIKARA , MASUBUCHI YUICHI , TAKIMOTO JUN-ICHI , KOYAMA KIYOHITO
Published: January 2005

Blends of immiscible liquids with different dielectric constants and viscosities were known to show the ER effect due to the change of the domain structure by the electric field. In this paper, we report on our attempt to explore the possibility of the magnetic analog of these blend-type ER fluids. Water-based ferrofluid was blended with silicone oil with higher viscosity than the ferrofluid, in order to see whether the negative MR effect can be induced. The domain structure and the viscosity under the magnetic field and shear flow were studied. Growth of the droplet due to coalescence was observed under the field, which resulted in the gradual decrease of the shear viscosity.
Domain Structure Control by Electric Field
Authors: KOYAMA KIYOHITO
Published: January 2005

In general, immiscible liquid blends form a domain structure; for example, in a binary blend, one component fluid forms droplets, and another forms the matrix. We investigated the change of this domain structure induced by an electric field. The domain structure change depended strongly on the mixing fraction and electric field strength. The resulting viscosity change of the blend was also reported.
CALCULATION OF THE HYDRODYNAMIC CHARACTERISTIC OF THE ER-FLUID IN A PLANE CHANNEL-CONDENSER FOR THE EXPONENTIAL-LAW FLUID FLOW
Authors: KOROBKO E. V. , EGOROV N. I. , MOKEEV A. A.
Published: January 2005

A historical survey is made of the works devoted to physico-mathematical modeling of transfer processes of the ER-fluids whose peculiarities are determined by the regularities in changing the internal structure of a liquid carrier in the presence of an electric field. The difficulties encountered in the statement and complete solution of a system of the Maxwell equations and the motion equation of a fluid with complicated rheology are discussed.

For the first time the hydrodynamic characteristic (flow rate, pressure drop, velocity profile) of an ER-fluid in a channel-condensor of the simplist form, i.e. with a rectangular cross-section are calculated using the most complicated phenomenological equation of state, i.e. having the exponential — law dependence of shear stress on shear rate and applied electric field intensity. The relations obtained can be employed in designing the hydrodynamic systems in a wide range of flow velocities and electric-field intensities.
INTERACTION BETWEEN PARTICLES AND PARTICLE CHAINS IN ELECTRORHEOLOGICAL FLUIDS
Authors: GU GUO-QING , HUI P. M.
Published: January 2005

The electric potential in a granular system consisting of spherical inclusions in the presence of an external applied electric field is studied in detail within the framework of the Rayleigh identity. The effects of induced charges on the inclusions are taken into account explicitly. The method, in principle, includes the effects of all multipoles. The method is applied to study the interaction between two inclusions. The standard form of interaction between inclusions widely used in studying ER fluids is recovered as an approximation of our general approach. We then apply the method to a chain of inclusions. Analytic expressions for the electrostatic energy per inclusion and the electric field are obtained for the case in which the chain is parallel to the applied field. Our result reduces to the form used in the literature when appropriate approximation is taken. The method is further extended to study the interaction between chains of inclusions. An approximate expression is obtained for the force between two chains of inclusions. Our approach provides a rigorous framework for determining the interaction between inclusions and chains of inclusions to arbitrary accuracy.
ELECTRICALLY INDUCED VISCOSITY CHANGE IN IMMISCIBLE LIQUID BLEND
Authors: KIMURA HIROSHI , AIKAWA KOICHIRO , MASUBUCHI YUICHI , TAKIMOTO JUN-ICHI , KOYAMA KIYOHITO
Published: January 2005

A blend of two immiscible liquid forms a domain structure. The domain structure strongly affects the macroscopic properties of the blend. We focused on the domain structure and viscosity change by applying an electric field in a urethane-modified polypropylene glycol (UPPG) and dimethylsiloxane (DMS) immiscible liquid blend. In the case that UPPG forms droplets, the domain structure changed drastically by the electric field application and the resulting viscosity change was observed.
THE DECOHERENCE CRITERION
Authors: ALFINITO ELEONORA , VIGLIONE ROSARIO G. , VITIELLO GIUSEPPE
Published: January 2005

The decoherence mechanism signals the limits beyond which the system dynamics approaches the classical behavior. We show that in some cases decoherence may also signal the limits beyond which the system dynamics has to be described by quantum field theory, rather than by quantum mechanics.
FRAGMENTATION OF SOIL INITIATORS: APPLICATION OF THE PORE-SOLID FRACTAL MODEL
Authors: MILLÁN H.
Published: January 2005

The quantification of fragmentation of natural, polidisperse, porous media using fractal models is well documented in the literature. However, in many cases, fractal exponents (fractal fragmentation dimension) and coefficients (fractal lacunarity) arising from a power law behavior do not make clear differences between different media. In the present work, the pore-solid fractal (PSF) model was used as a new fractal approach for deriving four scaling parameters (fractal dimension of the particle-size distribution, fractal fragmentation dimension of the fragment-size distribution, probability of fragmentation and scaling factor) from soil initiators subjected to different energy density input. The fractal fragmentation dimension for all soil samples was Df=2.42±0.16 without correlating with the energy expended in the fragmentation process. By contrast, probability of fragmentation and scaling factor correlated significantly with the energetic term. The PSF model is useful for estimating a group of scaling parameters more appropriate for the quantification of complex patterns associated to fragment-size distributions.
APPLICATION OF DETRENDED FLUCTUATION ANALYSIS TO MONTHLY AVERAGE OF THE MAXIMUM DAILY TEMPERATURES TO RESOLVE DIFFERENT CLIMATES
Authors: KURNAZ M. L.
Published: January 2005

Detrended fluctuation analysis (DFA) is used to investigate correlations between the monthly average of the maximum daily temperatures for different locations in the continental United States and the different climates these locations have. When we plot the scaling exponents obtained from the DFA versus the standard deviation of the temperature fluctuations, we observe crowding of data points belonging to the same climates. Thus, we conclude that by observing the long-time trends in the fluctuations of temperature it would be possible to distinguish between different climates.
LAPLACIAN TRANSPORT TOWARDS PARTIALLY PASSIVATED 2D IRREGULAR INTERFACES: A CONJECTURAL EXTENSION OF THE MAKAROV THEOREM
Authors: SAPOVAL B. , COSTA M. H. A. S. , ANDRADE J. S. , FILOCHE M.
Published: January 2005

In several phenomena of practical interest, such as catalyst deactivation, fouling in heat transfer and other systems of technological and scientific relevance, an irregular surface accessed by diffusion can be progressively passivated. In a diffusion limited situation, an interface that works unevenly due to Laplacian screening is simultaneously and unevenly passivated. To study this phenomenon, we describe a process in which the regions of the surface that are initially working, are transformed into passive, reflecting zones. As a consequence, at each step, a new part of the interface becomes active. In turn, this new active zone is passivated, and so on. It is found that the length of the successive active zones remains approximately constant for a prefractal interface. The concept of active zone in Laplacian transport can then be successfully extended to elucidate this self-limiting behavior of the passivation process. A conjecture is then proposed which states that, in D=2, the information dimension of the harmonic measure on a fractal supporting a "passivated or reflecting subfractal" (of smaller dimension) is equal to 1. This constitutes an extension of Makarov theorem. From our results, fractal geometry is revealed as a potential candidate to engineer substrate morphologies that are robust to Laplacian passivation.
NUMERICAL ANALYSIS ON THE SIERPINSKI GASKET, WITH APPLICATIONS TO SCHRÖDINGER EQUATIONS, WAVE EQUATION, AND GIBBS' PHENOMENON
Authors: COLETTA KEVIN , DIAS KEALEY , STRICHARTZ ROBERT S.
Published: January 2005

We show how to improve the finite element method on the Sierpinski gasket (SG) to allow arbitrary partitions of the space. We use this method to study numerically solutions of the Schrödinger equation with well-type potentials, and the wave equation. We also show that Fourier series-type expansions on SG of functions with jump discontinuities appear to exhibit a self-similar Gibbs' phenomenon.
EDITORIAL: HISTORY OF HAND SURGERY IN HONG KONG
Authors: Wu Wing-Cheung
Published: January 2005

The development of hand surgery in Hong Kong can be largely divided into three phases: the early years, the 1960s and 70s, and the present. In the immediate post-World War II years, incidence of infectious diseases was high; there were many patients with tuberculosis, poliomyelitis, leprosy and osteomyelitis. In the 1960s and 70s, the light industry revolution brought along many patients with serious hand injuries caused by machines. Dr Yen-Shui Tsao was the first local surgeon trained in hand surgery. Prof. SP Chow and Prof. PC Leung were the two pioneers who developed this subspecialty and microsurgery during that period.

At present, with the change in economic environment, the disease pattern has also changed. Despite our heavy clinical involvement, we have been very active in academic researches. The Hong Kong Society for Surgery of Hand was formed in 1986. For the past 15 years, the society organized Workshops and Annual Congresses attended by overseas speakers, including surgeons from China. It also provided scholarships for Fellows of the Asia-Pacific countries. In addition, the society provided the participants with the chance to exchange ideas and forge friendships. Hong Kong has thus been and will continue to be the meeting point of the East and the West.
APPLICATION OF EXAFS TO MOLTEN SALTS AND IONIC LIQUID TECHNOLOGY
Authors: Hardacre Christopher
Published: January 2005

▪ Abstract  This paper describes the use of extended X-ray absorption fine structure spectroscopy (EXAFS) to examine the structure of molten salts and ionic liquids and species dissolved in them. The EXAFS theory is briefly described as are the methods by which EXAFS of these systems can be studied. A range of applications have used EXAFS to investigate the structure of metallic species in ionic liquids from extraction studies to catalysts. The area of structural investigations of ionic liquids is still being developed, although growing rapidly, whereas the structure of molten salts has been studied using EXAFS in more detail.
Relative contribution of chloride channels and transporters to regulatory volume decrease in human glioma cells
Authors: Ernest Nola Jean , Weaver Amy K. , Van Duyn Lauren B. , Sontheimer Harald W.
Published: January 2005

Primary brain tumors (gliomas) often present with peritumoral edema. Their ability to thrive in this osmotically altered environment prompted us to examine volume regulation in human glioma cells, specifically the relative contribution of Cl− channels and transporters to this process. After a hyposmotic challenge, cultured astrocytes, D54-MG glioma cells, and glioma cells from human patient biopsies exhibited a regulatory volume decrease (RVD). Although astrocytes were not able to completely reestablish their original prechallenge volumes, glioma cells exhibited complete volume recovery, sometimes recovering to a volume smaller than their original volumes (VPost-RVD < Vbaseline). In glioma cells, RVD was largely inhibited by treatment with a combination of Cl− channel inhibitors, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and Cd2+ (VPost-RVD > 1.4*Vbaseline). Volume regulation was also attenuated to a lesser degree by the addition of R-(+)-[(2- n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1 H-inden-5-yl)oxy]acetic acid (DIOA), a known K+-Cl− cotransporter (KCC) inhibitor. To dissect the relative contribution of channels vs. transporters in RVD, we took advantage of the comparatively high temperature dependence of transport processes vs. channel-mediated diffusion. Cooling D54-MG glioma cells to 15°C resulted in a loss of DIOA-sensitive volume regulation. Moreover, at 15°C, the channel blockers NPPB + Cd2+ completely inhibited RVD and cells behaved like perfect osmometers. The calculated osmolyte flux during RVD under these experimental conditions suggests that the relative contribution of Cl− channels vs. transporters to this process is ∼60–70% and ∼30–40%, respectively. Finally, we identified several candidate proteins that may be involved in RVD, including the Cl− channels ClC-2, ClC-3, ClC-5, ClC-6, and ClC-7 and the transporters KCC1 and KCC3a.
Mechanism of cardiovascular effects of nociceptin microinjected into the nucleus tractus solitarius of the rat
Authors: Chitravanshi Vineet C. , Sapru Hreday N.
Published: January 2005

Microinjections (100 nl) of 0.15, 0.31, 0.62, and 1.25 mmol/l of nociceptin into the medial nucleus tractus solitarius (mNTS) elicited decreases in mean arterial pressure (11 ± 1.8, 20 ± 2.1, 21.5 ± 3.1, and 15.5 ± 1.9 mmHg, respectively) and heart rate (14 ± 2.7, 29 ± 5.5, 39 ± 5.2, and 17.5 ± 3.1 beats/min, respectively). Because maximal responses were elicited by microinjections of 0.62 mmol/l nociceptin, this concentration was used for other experiments. Repeated microinjections of nociceptin (0.62 mmol/l) into the mNTS, at 20-min intervals, did not elicit tachyphylaxis. Bradycardia induced by microinjections of nociceptin into the mNTS was abolished by bilateral vagotomy. The decreases in mean arterial pressure and heart rate elicited by nociceptin into the mNTS were blocked by prior microinjections of the specific ORL1-receptor antagonist [N-Phe1]-nociceptin-(1–13)-NH2 (9 mmol/l). Microinjections of the ORL1-receptor antagonist alone did not elicit a response. Prior combined microinjections of GABAA and GABAB receptor antagonists (2 mmol/l gabazine and 100 mmol/l 2-hydroxysaclofen, respectively) into the mNTS blocked the responses to microinjections of nociceptin at the same site. Prior microinjections of ionotropic glutamate receptor antagonists (2 mmol/l NBQX and 5 mmol/l d-AP7) also blocked responses to nociceptin microinjections into the mNTS. These results were confirmed by direct neuronal recordings. It was concluded that 1) nociceptin inhibits GABAergic neurons in the mNTS, 2) GABAergic neurons may normally inhibit the release of glutamate from the terminals of peripheral afferents in the mNTS, and 3) inhibition of GABAergic neurons by nociceptin results in an increase in the release of glutamate in the mNTS, which in turn elicits depressor and bradycardic responses via activation of ionotropic glutamate receptors on secondary mNTS neurons.
VEGF-A splice variants and related receptor expression in human skeletal muscle following submaximal exercise
Authors: Gustafsson T. , Ameln H. , Fischer H. , Sundberg C. J. , Timmons J. A. , Jansson E.
Published: January 2005

VEGF-A contributes to muscle tissue angiogenesis following aerobic exercise training. The temporal response of the VEGF-A isoforms and their target receptors has not been comprehensively profiled in human skeletal muscle. We combined submaximal exercise with and without reduced leg blood flow to establish whether ischemia-induced metabolic stress was an important physiological stimuli responsible for regulating the VEGF-A system in humans. Nine healthy men performed two 45-min bouts of one-leg knee-extension exercise, with and without blood flow restriction. Muscle biopsies were obtained at rest and 2 and 6 h after exercise. Expression (mRNA) of the VEGF-A splice variants and related receptors [VEGF receptor (VEGFR)-1, VEGFR-2, and neuropilin-1] was determined by using qPCR. VEGF-Atotal expression increased more robustly after exercise with reduced blood flow, and initially this principally reflected an increase in VEGF-A165. Six hours after exercise, there was a relatively greater increase in VEGF-A189, and this response was not influenced by blood flow conditions. VEGFR-1 mRNA expression increased 2 h after exercise, and neuropilin-1 expression was transiently reduced, while all three receptors increased by 6 h. There was no evidence for the expression of the inhibitory VEGF-A165B variant in human skeletal muscle. Our study, reflecting both VEGF-A ligand and receptors, implicates metabolic perturbation as a regulator of human muscle angiogenesis and demonstrates that VEGF-A splice variants are distinctly regulated. Our findings also indicate that all three receptor genes exhibit different pretranslational regulation, in response to exercise in humans.
Degradation of Temporal Resolution in the Auditory Midbrain After Prolonged Deafness Is Reversed by Electrical Stimulation of the Cochlea
Authors: Vollmer Maike , Leake Patricia A. , Beitel Ralph E. , Rebscher Stephen J. , Snyder Russell L.
Published: January 2005

In an animal model of prelingual deafness, we examined the anatomical and physiological effects of prolonged deafness and chronic electrical stimulation on temporal resolution in the adult central auditory system. Maximum following frequencies ( Fmax) and first spike latencies of single neurons responding to electrical pulse trains were evaluated in the inferior colliculus of two groups of neonatally deafened cats after prolonged periods of deafness (>2.5 yr): the first group was implanted with an intracochlear electrode and studied acutely (long-deafened unstimulated, LDU); the second group (LDS) received a chronic implant and several weeks of electrical stimulation (pulse rates ≥300 pps). Acutely deafened and implanted adult cats served as controls. Spiral ganglion cell density in all long-deafened animals was markedly reduced (mean <5.8% of normal). Both long-term deafness and chronic electrical stimulation altered temporal resolution of neurons in the central nucleus (ICC) but not in the external nucleus. Specifically, LDU animals exhibited significantly poorer temporal resolution of ICC neurons (lower Fmax, longer response latencies) as compared with control animals. In contrast, chronic stimulation in LDS animals led to a significant increase in temporal resolution. Changes in temporal resolution after long-term deafness and chronic stimulation occurred broadly across the entire ICC and were not correlated with its tonotopic gradient. These results indicate that chronic electrical stimulation can reverse the degradation in temporal resolution in the auditory midbrain after long-term deafness and suggest the importance of factors other than peripheral pathology on plastic changes in the temporal processing capabilities of the central auditory system.
On the Division of Cortical Cells Into Simple and Complex Types: A Comparative Viewpoint
Authors: Ibbotson M. R. , Price N.S.C. , Crowder N. A.
Published: January 2005

Hubel and Weisel introduced the concept of cells in cat primary visual cortex being partitioned into two categories: simple and complex. Subsequent authors have developed a quantitative measure to distinguish the two cell types based on the ratio between modulated responses at the stimulus frequency ( F1) and unmodulated ( F0) components of the spiking responses to drifting sinusoidal gratings. It has been shown that cells in anesthetized cat and monkey cortex have bimodal distributions of F1/ F0ratios. A clear local minimum or dip exists in the distribution at a ratio close to unity. Here we present a comparison of the distributions of the F1/ F0ratios between cells in the primary visual cortex of the eutherian cat and marsupial Tammar wallaby, Macropus eugenii. This is the first quantitative description of any marsupial cortex using the F1/ F0ratio and follows earlier papers showing that cells in wallaby cortex are tightly oriented and spatial frequency tuned. The results reveal a bimodal distribution in the wallaby F1/ F0ratios that is very similar to that found in the rat, cat, and monkey. Discussion focuses on the mechanisms that could lead to such similar cell distributions in animals with diverse behaviors and phylogenies.
Direct Comparison between Two 1-84PTH Assays in Dialysis Patients
Authors: Kazama Junichiro J. , Yamamoto Suguru , Kameda Shigemi , Maruyama Hiroki , Narita Ichiei , Shigematsu Takashi , Gejyo Fumitake
Published: January 2005

Background/Aim: Today, two kinds of 1-84PTH assays are available in clinical practice. Few studies have directly compared the results of these assays in the same plasma. Methods: Plasma samples were collected from 235 dialysis patients and analyzed by the 1-84PTH-IRMA, intact PTH-IRMA, 1-84PTH-CLIA, and intact PTH-CLIA assays simultaneously. Results: The results obtained by the 1-84PTH-IRMA and 1-84PTH-CLIA were highly correlated to each other (r2 = 0.971, p < 0.0001). In 90.2–92.3% of patients, the assays agreed when classifying them into three categories based on the K/DOQI guidelines. However, the 1-84PTH assays agreed in only 41.3–83.4% of patients when classifying them into two categories by calculating 1-84PTH/(intact PTH – 1-84PTH). Conclusion: The results obtained by the two assays could be regarded as comparable in clinical practice. However, the 1-84PTH/(intact PTH-1-84PTH) ratio has to be carefully applied since it amplified the error of these assays.
Serum Antioxidant Capacity and the Risk of Contrast Medium Nephropathy
Authors: Elias Mazen , Swae’ed Suleiman , Shneor Amir , Turgman Yoav , Saliba Walid , Goldstein Lee H. , Rosenfeld Tiberio
Published: January 2005

Introduction: The use of contrast medium can result in an acute reduction in renal function. The exact mechanism of this side effect is not yet fully understood. There is accumulating evidence that reactive oxygen species have a role in renal damage. Prophylactic administration of antioxidant drugs could prevent this reduction in renal function. We examined whether there is a correlation between the antioxidant capacity of the serum and the risk of contrast medium nephropathy. Methods: We studied prospectively 193 patients with normal renal function who underwent cardiac catheterization. Serum haptoglobin, uric acid, albumin and the total antioxidant capacity were measured before the injection of contrast media. Serum urea and creatinine concentrations were measured before angiography and on days 3 and 7 following the procedure. Results: Eleven patients developed mild renal failure. We compared the serum levels of antioxidant compounds of this group with the serum levels of these compounds in patients who did not develop renal damage. No statistical significant difference in the baseline levels of antioxidant species was found between the two groups. Conclusions: These prospective data indicate that among low-risk patients with normal renal function, baseline levels of antioxidant material did not predict the possible development of contrast medium nephropathy.
Blockade of Angiotensin II with Losartan Attenuates Transforming Growth Factor-β1 Inducible Gene-h3 (βig-h3) Expression in a Model of Chronic Cyclosporine Nephrotoxicity
Authors: Sun Bo Kyung , Li Can , Lim Sun Woo , Choi Bum Soon , Lee Suk Hee , Kim In San , Kim Yong Soo , Bang Byung Kee , Yang Chul Woo
Published: January 2005

Background: We recently demonstrated that upregulation of the transforming growth factor (TGF)-β1 inducible gene-h3 (βig-h3) is associated with tubulointerstitial fibrosis (TIF) in a rat model of chronic cyclosporine A (CsA) nephrotoxicity. This study investigated the association between βig-h3 expression and TIF during losartan treatment in this model. Methods: Adult Sprague-Dawley rats kept on a salt-depleted diet (0.05% sodium) were treated daily for 4 weeks with vehicle (olive oil, 1 ml/kg), CsA (15 mg/kg) or both CsA and losartan (10 mg/kg in drinking water). The effect of losartan on βig-h3 expression was evaluated using in situ hybridization, immunohistochemistry and immunoblotting. Histopathology, expressions of TGF-β1 and intrarenal angiotensin II were compared across treatment groups. Results: Concurrent administration of losartan significantly attenuated βig-h3 mRNA and protein expression within the tubulointerstitium of CsA-treated kidneys. This was accompanied by the retardation of TIF (18 ± 5 vs. 39 ± 5%, p < 0.01 vs. CsA) and the expression of TGF-β1 mRNA (336 ± 49 vs. 685 ± 63%, p < 0.01 vs. CsA) and the number of angiotensin II-positive glomeruli (18 ± 5 vs. 38 ± 6, p < 0.05 vs. CsA). Conclusion: Losartan is capable of abrogating the upregulation of TGF-β1 and βig-h3 expression, and this is associated with attenuated tubulointerstitial fibrosis in chronic CsA nephrotoxicity.
Residual Urinary Concentrating Ability and AQP2 Expression in a Rat Model for Chronic Renal Failure
Authors: Suzuki Katsuya , Hatano Ryo , Michimata Mari , Kazama Itsuro , Suzuki Michiko , Miyama Noriyuki , Sato Akira , Satomi Susumu , Ejima Yutaka , Yanagisawa Teruyuki , Matsubara Mitsunobu
Published: January 2005

Background: In chronic renal failure (CRF), a defect in urinary concentrating ability develops gradually as the renal failure progresses. Although several molecular mechanisms associated with renal urinary concentration are reported to be impaired in a rat model for renal failure, the mechanisms underlying residual urinary concentration ability in CRF remain to be elucidated. Methods: Rats that underwent an 8-week recovery period after 5/6 nephrectomy were used as the model for CRF. Urinary concentration was induced by 24-hour water restriction. Plasma osmolality and arginine vasopressin (AVP) were measured from blood sampled by inserting a catheter into the femoral artery before and after the water restriction. AQP2 mRNA expression in the inner medulla was examined by competitive PCR and in situ hybridization, and protein expression, by Western blotting. Rats that underwent sham operation were used as control. Results: Water restriction significantly reduced urine volume and increased urine osmolality in CRF rats, although such changes were much less than those in sham-operated rats. Plasma AVP was elevated at the basal condition, and further elevation was noted after water restriction. AQP2 mRNA signals were significantly intensified by water restriction even in CRF rats, although the increase was limited as in the case of urine osmolality. Western blotting also showed a small but significant enhancement of protein signals in response to water restriction in CRF rats. Conclusions: We noted a weak but significant response of AQP2 expression to dehydration in CRF rats. This response in the collecting duct may be one of the factors contributing to residual urinary concentrating ability in CRF.
Effect of Hemodiafiltration against Radical Stress in the Course of Blood Purification
Authors: Tomo Tadashi , Matsuyama Kazuhiro , Nasu Masaru
Published: January 2005

The involvement of radical stress has been suggested as a cause for complications in patients on dialysis, such as arteriosclerosis, dialysis-related amyloidosis, etc. It has been reported that the increase in radical stress is not only seen in renal failure, but that its amplified effect is also seen in the process of blood purification. Our group has reported on the radical stress-reducing effect of HDF. We performed four types of blood purification (HD; on-line HDF; pre, on-line HDF; post, P/P HDF) in patients on maintenance dialysis using the polysulfone (APS) dialyzer. The change in radical related markers such as pentosidine (total, free) and CML (total, free), and the CTL/Cr ratio, and the hydroperoxide radicals were studied. In HDF (post, pre), the amplification rate of hydroperoxide radicals was significantly low, whereas the reduction rate of CTL/Cr ratio as index for hydroxy radicals was significantly higher in on-line HDF than in HD. Both the total CML and T-pentosidine increased in HD but showed a decrease in HDF. As HDF uses large amounts of replacement solution, the following effects can be expected: (a) suppression of the amplification of hydroperoxide radicals and suppression of the amplification of hydroxy radicals, and (b) suppression of fat oxidation by AGEs themselves. These antiradical stress effects are presumed to be exerted by effective removal of radical carrier protein, denatured protein, and complement protein in HDF, by dilution of radicals by massive use of replacement solution, and by the sequential reduction of the excitation and amplification effects.
Task-Based Profile of Vocal Intensity Decline in Parkinson’s Disease
Authors: Rosen Kristin M. , Kent Raymond D. , Duffy Joseph R.
Published: January 2005

This study examines intensity decay in the phonation of persons with Parkinson’s disease (PD). The decline in vocal intensity (determined by linear regression of the intensity envelope) was compared across the following tasks: vowel prolongation, syllable repetition (diadochokinesis, DDK), isolated sentences and conversation. In contrast to previous studies, PD speakers demonstrated no significant differences in intensity decline from healthy speakers in vowel prolongation. The vocal intensity of speakers with PD declined more rapidly than that of controls in DDK tasks. While intensity slopes in conversation were more variable in both groups, some participants with PD exhibited abrupt changes in intensity. Results indicate that the DDK is particularly useful for describing intensity decay associated with PD. However, considering the inconsistent group differences across tasks, and the discrepant findings from previous studies, intensity decay is not a robust symptom of PD.
La perception du débit en langue seconde
Authors: Schwab Sandra , Grosjean François
Published: January 2005

Non-native speakers of a second language often report that the speech ratein that language is faster than the rate in their own language. So as to comparespeech rate perception by native (French) and non-native (Swiss German) speakers,and to determine if rate estimation by non-native speakers is correlated withtheir level of comprehension, we asked two groups of 96 participants, native andnon-native speakers of French, to listen to short stories read at slow, medium andfast rates. They were asked to answer a few comprehension questions and to givean estimate of the speech rate. The results obtained show that there is indeed adifference between the two groups: the faster the physical speech rate, the greaterthe impression of speed in the non-native speakers as compared with the nativespeakers. In addition, when speech rate is slow and normal, there is a significantnegative correlation between oral comprehension and perceived rate: the lowerthe comprehension, the higher the estimated rate.
Active and Passive Cigarette Smoking and Risk of Intracranial Meningioma
Authors: Phillips Leslie E. , Longstreth Jr W.T. , Koepsell Thomas , Custer Brian S. , Kukull Walter A. , van Belle Gerald
Published: January 2005

Motivated by prior studies, we examined associations between cigarette smoking and risk of intracranial meningioma in a population-based case-control study, including 200 cases and 2 controls matched to each case on age and sex. Subjects were asked to recall their history of active and passive cigarette smoking occurring 10 or more years before the date of meningioma surgery. Ever active smoking was associated with an increased risk of meningioma in men (OR = 2.1; 95% CI 1.1–4.2) but not in women (OR = 0.7; 95% CI 0.5–1.1). The statistical interaction by gender was significant (p = 0.01). In men, risk increased with increasing number of cigarettes smoked daily (p for trend = 0.04). In women, the trend was opposite (p for trend = 0.08). Among never active smokers, passive smoking from a spouse was associated with increased risk in both sexes (OR 2.0; 95% CI 1.1–3.5), and risk increased with increasing duration of exposure (p for trend = 0.02). Uncertain is whether these findings reflect a true biological phenomenon or result from chance or uncontrolled confounding.
Clinicopathological Features of Head and Neck Adenosquamous Carcinoma
Authors: Sheahan Patrick , Toner Mary , Timon Conrad V.I.
Published: January 2005

Adenosquamous carcinoma is a rare tumour which is characterized pathologically by the simultaneous presence of distinct areas of squamous cell carcinoma and adenocarcinoma. The origin of adenosquamous carcinoma is controversial; however, it is generally considered to be aggressive and associated with a dismal prognosis. In the present study, the medical and pathological records of 4 patients with head and neck adenosquamous carcinoma are reviewed. In 1 patient, the tumour arose from an area of carcinoma in situ of surface epithelium. The origin from surface epithelium was not evident in any of the others. Perineural invasion was present in 3 patients. Three patients had evidence of cervical metastases. One patient died of postoperative complications, 1 suffered from local recurrence and developed distant metastases and 2 were alive with no evidence of disease over 30 months later. Adenosquamous carcinoma is an aggressive tumour; however, with appropriate treatment, some patients may remain well beyond 2 years.
Blink Reflex R2 Recovery Curves in Patients with Facial Palsy within Ten Days after Onset
Authors: Toda Naoki , Nakamura Katsuhiko , Takeda Noriaki
Published: January 2005

The purpose of this study was to investigate the acute changes in blink reflex responses in patients with facial palsy. We used the blink reflex R2 recovery curves as an index of the excitability of the blink reflex neural circuit and evaluated the excitability of the blink reflex within 10 days after onset. Twelve patients with peripheral facial palsy were selected on condition that the degree of facial palsy was so mild that R2 responses of the blink reflex were measurable on the affected side, and they were compared with 12 healthy volunteers. Conditioning and test electrical stimuli were delivered on the affected side of the supraorbital nerve. Ipsilateral R2 response (iR2) of the blink reflex in patients was significantly enhanced at interstimulus intervals (ISIs) between conditioning and test stimuli from 100 to 1,000 ms, in comparison with the control subjects. These findings suggested hyperexcitability of the blink reflex neural circuit in patients with facial palsy. In addition to iR2, contralateral R2 response (cR2) in the patients was also significantly increased at ISIs of 100–1,000 ms to the same extent as the enhancement of iR2. All these findings suggested that the hyperexcitable changes developed in a common pathway of iR2 and cR2, but not in the ipsilateral facial motor neurons. It is suggested that the hyperexcitability of the neural circuit of the blink reflex during an acute period of facial palsy is an adaptive response to compensate for impaired facial motor function.
Concentration of Transforming Growth Factor β2 in Aqueous Humor
Authors: Yamamoto Naoki , Itonaga Koichiro , Marunouchi Tohru , Majima Kiyoyuki
Published: January 2005

The total transforming growth factor (TGF) β2 concentration in the anterior chamber aqueous humor of 96 cataract patients with ages ranging from 17 to 88 years was measured using ELISA to investigate the changes that occur with age, difference of axial length, difference of localization of opacification of the cataractous lens and complications with other eye diseases. It was found that the total TGF-β2 concentration (1) decreases with age, (2) shows slight changes with axial length, (3) has slight changes with difference of localization of opacification, (4) is significantly high in patients with concurrent open-angle glaucoma (p < 0.05), (5) is high in patients with complicating diabetes who have undergone panretinal photocoagulation for diabetic retinopathy (p < 0.05) and (6) is low in patients with atopic cataracts. There have been several reports on point 4 above, but none to date of the other points. These findings provide useful information on the intraocular activity of TGF-β2.
Changes in Foveal Thickness and Macular Function after Transpupillary Thermotherapy for Age-Related Macular Degeneration
Authors: Ishikawa Kohei , Terasaki Hiroko , Kobayashi Chiaki , Niwa Yasuhiro , Piao Chang-Hua , Ito Yasuki , Kondo Mineo , Miyake Yozo
Published: January 2005

Purpose: To evaluate the effect of transpupillary thermotherapy (TTT) on foveal thickness and macular function in eyes with choroidal neovascularization (CNV) associated with age-related macular degeneration. Methods: Sixteen eyes with occult CNV and 6 eyes with classic CNV were treated with TTT. Optical coherence tomography and focal macular electroretinograms (FMERGs) elicited by a 15-degree stimulus were performed before, 3 months after TTT in 22 eyes and 6 months after TTT in 18 eyes. Results: Before TTT, the fovea in 20 of the 22 eyes with CNV was significantly thicker than that of normal subjects. The foveal thickness was reduced after TTT in 11 of 14 eyes with occult CNV and remained unchanged in 2 eyes. One eye with occult CNV before TTT developed a classic CNV with significant macular edema and increased foveal thickness 3 months after TTT. The amplitudes of the FMERGs were reduced in all eyes before TTT. In eyes with occult CNV, the mean b-wave amplitude increased significantly after TTT (p = 0.0260 at 3 months, p = 0.0142 at 6 months). When the change of foveal thickness was less than 20% after TTT, all eyes with occult CNV had a 30% or more increase in the b-wave amplitude. In eyes with classic CNV, the mean amplitude of the a- and b-waves did not change significantly after TTT. Conclusions: TTT improves macular function in eyes with occult CNV associated with age-related macular degeneration more when the change of foveal thickness is slight.
Effects of Endothelin-1 on Human Trabecular Meshwork Cell Contraction
Authors: Cellini Mauro , Versura Piera , Trerè Davide , Campos Emilio C.
Published: January 2005

Trabecular meshwork (TM) cells are now considered to play an active role in the aqueous outflow mechanism, since they exhibit smooth muscle-like contractile properties. Endothelin-1 (ET-1), a potent vasoconstrictor peptide, has been proposed to play a role in the local regulation of aqueous outflow and intra-ocular pressure control. We propose an in vitro culture model as a method in the study of ET-1-induced human trabecular meshwork (HTM) cell contractility. Experiments were performed on semi-confluent HTM cells (primary cultures established from normotensive human donor eyes) at the 2nd passage with PBS as control, ET-1, sarafotoxin 6c (a selective endothelin B receptor agonist) and Y-27632 (a selective inhibitor of rho-associated kinase). The contractile status of the cells was evaluated by a morphometric analysis of the cell area, assuming that HTM cells in culture are able to reduce their area as a consequence of cytoskeletal contraction rather than regulatory volume decrease. Our data indicate that image analysis of the HTM cell area can be a reliable method in the study of TM cell contractility, since it utilizes human cells and offers versatile opportunities for the pharmacological evaluation of drugs controlling HTM cell status.