bluuebunny/crossref_metadata_2025 huggingface dataset:
ONE-PARTICLE SUBSPACE OF THE GLAUBER DYNAMICS GENERATOR FOR CONTINUOUS PARTICLE SYSTEMS
Authors: KONDRATIEV YURI , MINLOS ROBERT , ZHIZHINA ELENA
Published: January 2005

We consider a Glauber-type stochastic dynamics of continuous particle systems in ℝd. We construct a one-particle invariant subspace of the generator of this dynamics in the high temperature and low density regime. We prove that under some additional assumptions on the decay of the potential the restriction of the generator on the one-particle subspace is unitary equivalent to the operator of the multiplication by a bounded smooth real-valued function. As a consequence we estimate the spectral gap of the generator and find the second gap between the one-particle branch and the rest of the spectrum.
EMULATING PARALLEL PROGRAMMING ENVIRONMENTS IN THE HARNESS METACOMPUTING SYSTEM
Authors: MIGLIARDI MAURO , SUNDERAM VAIDY
Published: January 2005

Harness is an experimental metacomputing framework based on dynamic reconfigurability and extensible distributed virtual machines. The Harness system seeks to achieve two important goals. First, by enabling reconfiguration of the facilities provided by the virtual machine, Harness is able to provide specialized services appropriate to the platform and adapt to new technological developments. Second, Harness is able to adapt to application needs by configuring the required support services and programming environments on demand. In this paper, we describe the architecture and key features of Harness, and discuss the emulation of two distinct programming environments, namely Javaspaces and PVM, within the Harness environment.
ERRATA AND ADDENDA: DARBOUX CLASS OF COSMOLOGICAL FLUIDS WITH TIME-DEPENDENT ADIABATIC INDICES
Authors: Rosu H. C.
Published: January 2005

A number of corrections to the work in which I introduced one-parameter Darboux supersymmetric barotropic fluids in cosmology are performed. As addenda, the flat FRW case, which was left apart, is presented in detail in the supersymmetric approach.
COMPARISON OF RHEOLOGICAL AND ELECTRIC PROPERTIES OF ER FLUIDS BASED ON DIFFERENT MATERIALS
Authors: BÖSE HOLGER , TRENDLER ALEXANDRA
Published: January 2005

Rheological, electric and dielectric properties of two groups of ER fluids containing zeolite or perovskite particles with different cation compositions are compared. The dielectric behaviour at low field strength and the dependence of shear stress and current density on field strength and temperature in strong electric fields have been investigated. The results show striking differences in the dielectric properties and the temperature dependence of shear stress and current density between the two groups of materials. These differences can be correlated with the crystal structures of the particles and the polarization mechanisms involved. The ER activity in zeolite-based fluids is dominated by the conductivity and attributed to the mobility of the cations. In contrast the ER activity in perovskite-based ER fluids is dominated by the dielectric constant and attributed to the local displacement of ions.
p-d hybridization of noble metal halides
Authors: KOBAYASHI M. , IYETOMI H. , ONO S. , TOMOYOSE T.
Published: January 2005

The electronic band calculations of noble metal halides are studied to make the high ionic conducting origin of silver and cupper ions clear using the tight-binding method. The d bands of Ag ions are much more weakly coupled with the p bands of halogen ions, while those of Cu ions are much more strongly coupled with the p bands. The strength of p-d hybridization is discussed to connect with the activation energy for the ionic conduction. It is shown that the high ionic conductivity of AgX primary stems from combination of the deformability of the d shell and the weakness of the p-d hybridization.
A CONDUCTION MODEL DESCRIBING PARTICLE-PARTICLE INTERACTION IN THE CASE OF SURFACE CONDUCTING PARTICLES
Authors: GONON P. , FOULC J.-N. , ATTEN P.
Published: January 2005

We propose an analytical conduction model describing particle-particle interactions for the case of electrorheological fluids based on surface conducting particles. The system consisting of two contacting spheres immersed in a dielectric liquid is modeled by a distributed impedances network, from which we derive analytical expressions for the potential at the spheres surface, for the electric field in the liquid phase, and finally for the interaction force. The theoretical interaction force is compared with experimental results obtained on insulating spheres coated with a thin conducting polyaniline film. A good agreement is found between the theory and experiment.
ORIENTATION DYNAMICS OF MAGNETORHEOLOGICAL FLUIDS SUBJECT TO ROTATING EXTERNAL FIELDS
Authors: MELLE SONIA , RUBIO MIGUEL A. , FULLER GERALD G.
Published: January 2005

The formation and orientation of field-induced structures in magnetorheological (MR) fluids subject to rotating magnetic fields have been studied using two optical methods: scattering dichroism and small angle light scattering (SALS). The SALS patterns show how these chain-like aggregates follow the magnetic field with the same frequency but with a retarded phase angle for all the frequencies measured. Using scattering dichroism two different behaviors for both, dichroism and phase lag, are found below or above a critical frequency. Experimental results have been reproduced by a simple model considering the torques balance on the chain-like aggregates.
DERIVATION OF A SCALING LAW IN CLUSTER-CLUSTER AGGREGATIONS FROM A MODIFIED SMOLUCHOWSKI'S COAGULATION EQUATION
Authors: KALACHEV LEONID , MORIMOTO HISAO , MAEKAWA TORU
Published: January 2005

We derived a scaling relation in cluster-cluster aggregations from a modified Smoluchowski's coagulation equation and obtained the relation between the scaling exponents and the control parameter. The power laws in cluster-cluster aggregations derived from the scaling relations agreed with those of ferromagnetic colloidal particles obtained by a numerical calculation.
DECOMPOSITION OF LEBESGUE-CANTOR DEVIL'S STAIRCASE
Authors: KOLWANKAR KIRAN M.
Published: January 2005

We study the local oscillatory behavior of the Lebesgue-Cantor staircase function. The log-periodic oscillations at the points of the Cantor set are characterized exactly. It is shown that in the first approximation, the Lebesgue-Cantor staircase function can be written as the sum of power laws with imaginary exponent. And further approximation can be built using this series as a building block.
Cutaneous vascular responses to isometric handgrip exercise during local heating and hyperthermia
Authors: McCord Gregg R. , Minson Christopher T.
Published: January 2005

The dramatic increase in skin blood flow and sweating observed during heat stress is mediated by poorly understood sympathetic cholinergic mechanisms. One theory suggests that a single sympathetic cholinergic nerve mediates cutaneous active vasodilation (AVD) and sweating via cotransmission of separate neurotransmitters, because AVD and sweating track temporally and directionally when activated during passive whole body heat stress. It has also been suggested that these responses are regulated independently, because cutaneous vascular conductance (CVC) has been shown to decrease, whereas sweat rate increases, during combined hyperthermia and isometric handgrip exercise. We tested the hypothesis that CVC decreases during isometric handgrip exercise if skin blood flow is elevated using local heating to levels similar to that induced by pronounced hyperthermia but that this does not occur at lower levels of skin blood flow. Subjects performed isometric handgrip exercise as CVC was elevated at selected sites to varying levels by local heating (which is independent of AVD) in thermoneutral and hyperthermic conditions. During thermoneutral isometric handgrip exercise, CVC decreased at sites in which blood flow was significantly elevated before exercise (−6.5 ± 1.8% of maximal CVC at 41°C and −10.5 ± 2.0% of maximal CVC at 43°C; P < 0.05 vs. preexercise). During isometric handgrip exercise in the hyperthermic condition, an observed decrease in CVC was associated with the level of CVC before exercise. Taken together, these findings argue against withdrawal of AVD to explain the decrease in CVC observed during isometric handgrip exercise in hyperthermic conditions.
Spontaneous Activity and Properties of Two Types of Principal Neurons From the Ventral Tegmental Area of Rat
Authors: Koyama Susumu , Kanemitsu Yoshio , Weight Forrest F.
Published: January 2005

We investigated the spontaneous activity and properties of freshly isolated ventral tegmental area (VTA) principal neurons by whole cell recording and single-cell RT-PCR. The VTA principal neurons, which were tyrosine hydroxylase-positive and glutamic acid decarboxylase (GAD67)-negative, exhibited low firing frequency and a long action potential (AP) duration. The VTA principal neurons exhibited a calretinin-positive and parvalbumin-negative Ca2+-binding protein mRNA expression pattern. The VTA principal neurons were classified into two subpopulations based on their firing frequency coefficient of variation (CV) at room temperature (21–23°C): irregular-type neurons with a large CV and tonic-type neurons with a small CV. These two firing patterns were also recorded at the temperature of 34°C and in nystatin-perforated patch recording. In VTA principal neurons, the AP afterhyperpolarization (AHP) amplitude contributed to the firing regularity and AHP decay slope contributed to the firing frequency. The AHP amplitude in the irregular-type VTA principal neurons was smaller than that in the tonic-type VTA principal neurons. There was no significant difference in the AHP decay slope between the two-types of VTA principal neurons. Apamin-sensitive small-conductance Ca2+-activated K+(SK) channels contributed to the AHP and the regular firing of the tonic-type neurons but contributed little to the AHP and firing of the irregular-type neurons. In voltage-clamp tail-current analysis, in both conventional and nystatin-perforated whole cell recording, the apamin-sensitive AHP current density of the tonic-type neurons was significantly larger than that of the irregular-type neurons. We suggest that apamin-sensitive SK current contributes to intrinsic firing differences between the two subpopulations of VTA principal neurons.
Wiener-Kernel Analysis of Responses to Noise of Chinchilla Auditory-Nerve Fibers
Authors: Recio-Spinoso Alberto , Temchin Andrei N. , van Dijk Pim , Fan Yun-Hui , Ruggero Mario A.
Published: January 2005

Responses to broadband Gaussian white noise were recorded in auditory-nerve fibers of deeply anesthetized chinchillas and analyzed by computation of zeroth-, first-, and second-order Wiener kernels. The first-order kernels (similar to reverse correlations or “revcors”) of fibers with characteristic frequency (CF) <2 kHz consisted of lightly damped transient oscillations with frequency equal to CF. Because of the decay of phase locking strength as a function of frequency, the signal-to-noise ratio of first-order kernels of fibers with CFs >2 kHz decreased with increasing CF at a rate of about −18 dB per octave. However, residual first-order kernels could be detected in fibers with CF as high as 12 kHz. Second-order kernels, 2-dimensional matrices, reveal prominent periodicity at the CF frequency, regardless of CF. Thus onset delays, frequency glides, and near-CF group delays could be estimated for auditory-nerve fibers innervating the entire length of the chinchilla cochlea.
β-Amyloid Peptides Impair PKC-Dependent Functions of Metabotropic Glutamate Receptors in Prefrontal Cortical Neurons
Authors: Tyszkiewicz Joanna P. , Yan Zhen
Published: January 2005

The metabotropic glutamate receptors (mGluRs) have been implicated in cognition, memory, and some neurodegenerative disorders, including the Alzheimer's disease (AD). To understand how the dysfunction of mGluRs contributes to the pathophysiology of AD, we examined the β-amyloid peptide (Aβ)-induced alterations in the physiological functions of mGluRs in prefrontal cortical pyramidal neurons. Two potential targets of mGluR signaling involved in cognition, the GABAergic system and the N-methyl-d-aspartate (NMDA) receptor, were examined. Activation of group I mGluRs with (S)-3,5-dihydroxyphenylglycine (DHPG) significantly increased the spontaneous inhibitory postsynaptic current (sIPSC) amplitude, and this effect was protein kinase C (PKC) sensitive. Treatment with Aβ abolished the DHPG-induced enhancement of sIPSC amplitude. On the other hand, activation of group II mGluRs with (2R,4R)-4-aminopyrrolidine-2,4-dicarboxylate (APDC) significantly increased the NMDA receptor (NMDAR)-mediated currents via a PKC-dependent mechanism, and Aβ treatment also diminished the APDC-induced potentiation of NMDAR currents. In Aβ-treated slices, both DHPG and APDC failed to activate PKC. These results indicate that the mGluR regulation of GABA transmission and NMDAR currents is impaired by Aβ treatment probably due to the Aβ-mediated interference of mGluR activation of PKC. This study provides a framework within which the role of mGluRs in normal cognitive functions and AD can be better understood.
Palliativmedizin in der gynäkologischen Onkologie
Authors: Haller U. , Hepp H. , Winter R.
Published: January 2005

Ziel eines palliativmedizinischen Konzeptes ist es, die Lebensqualität von Patienten, welche mit einer lebensbedrohlichen Krankheit konfrontiert sind, und ihren Angehörigen zu verbessern. Im Vordergrund stehen, neben der Schmerztherapie, Ernährung sowie die Therapie bei akuter terminaler Dyspnoe und Dehydratation. Auch gynäkologisch-onkologische Akutkliniken sollten ein Palliativkonzept bereithalten, um der Patientin die letzte Phase ihres Daseins in Würde zu ermöglichen.
Calcium Channel Blocker versus Angiotensin II Receptor Blocker in Autosomal Dominant Polycystic Kidney Disease
Authors: Nutahara Kikuo , Higashihara Eiji , Horie Shigeo , Kamura Kouichi , Tsuchiya Ken , Mochizuki Toshio , Hosoya Tatsuo , Nakayama Tomohiro , Yamamoto Norio , Higaki Yoshio , Shimizu Toshiko
Published: January 2005

Background: Although hypertension is commonly found in patients with autosomal dominant polycystic kidney disease (ADPKD), there is no consensus about which antihypertensive agents are most appropriate. The effects of calcium channel blockers (CCB) and angiotensin II receptor blockers (ARB) on blood pressure and renoprotection were compared in hypertensive patients with ADPKD. Methods: We randomly assigned 49 participants to CCB amlodipine-based (2.5–10 mg/day) or ARB candesartan-based (2–8 mg/day) regimens. Twenty-five patients (13 males and 12 females) received amlodipine, and 24 patients (13 males and 11 females) received candesartan. This was followed up for 36 months. Results: Baseline characteristics were similar, and blood pressure was well controlled in both groups throughout the study period. Six out of 25 (24.0%) amlodipine and 1 out of 24 (4.2%) candesartan patients were terminated from the protocol due to a twofold increase in serum creatinine and/or decrease in creatinine clearance (Ccr) to half of the baseline. The renal event-free survival rate was significant (p < 0.05, Breslow-Gehan-Wilcoxon test). Serum creatinine was higher in the amlodipine group than in the candesartan group at 24 and 36 months (p < 0.05). The decrease in Ccr at 36 months was larger in the amlodipine group than in the candesartan group (ΔCcr: –20.9 ± 13.1 vs. –4.8 ± 13.8 ml/min, p < 0.01). Urinary protein excretion was significantly lower in the candesartan group than in the amlodipine group at 36 months. Urinary albumin excretion was significantly lower in the candesartan group than in the amlodipine group at 12, 24 and 36 months. Conclusions: The renoprotective effect of candesartan is considered more favorable than amlodipine in the treatment of ADPKD. This is independent of the antihypertensive effect per se.
The Where, What and Why of the Developing Renal Stroma
Authors: Cullen-McEwen Luise A. , Caruana Georgina , Bertram John F.
Published: January 2005

In recent years, a great deal has been learnt about the molecular regulation of kidney development. While most research has focused on the molecular regulation of ureteric branching morphogenesis and nephron formation, significant insights into the definition and functions of the renal stroma have emerged. Many molecules expressed in the developing renal stroma are now known to play significant regulatory roles in kidney development. However, the term ‘renal stroma’ continues to have different meanings to different researchers. This review clarifies this situation and defines the derivation, location and functions of the stroma in the developing metanephros.
Sulfated Hyaluronic Acid, a Potential Selectin Inhibitor, Ameliorates Experimentally Induced Crescentic Glomerulonephritis
Authors: Ogawa Daisuke , Shikata Kenichi , Matsuda Mitsuhiro , Akima Kazuo , Iwahashi Mitsuhiro , Okada Shinichi , Tsuchiyama Yoshinori , Shikata Yasushi , Wada Jun , Makino Hirofumi
Published: January 2005

Background/Aims: Sulfated polysaccharides are known to interfere with the binding of selectins and their ligands. Recently, we demonstrated that sulfated hyaluronic acid (SHA), a synthetic sulfated polysaccharide, showed preventive and therapeutic effects on experimental mesangial proliferative glomerulonephritis. Here we evaluated the protective potential of SHA on crescentic glomerulonephritis, using nephrotoxic serum (NTS) nephritis in Wistar-Kyoto (WKY) rats. Methods: Crescentic glomerulonephritis was induced by injection of NTS in WKY rats. Rats subsequently received intraperitoneal administration of SHA (0.5 or 1.5 mg/kg/day) or non-sulfated hyaluronic acid (HA) (1.5 mg/kg/day) for 14 days. The urinary protein excretion was measured, and expression of selectins, intraglomerular leukocytes and crescent formation were examined by immunohistochemistry. In addition, we examined the urinary protein excretion of SHA (1.5 mg/kg/day) administered from day 7 after the induction of crescentic glomerulonephritis. Results: The expression of P-selectin was increased in the glomerulus of crescentic glomerulonephritis. SHA reduced proteinuria, macrophage infiltration, and crescent formation in a dose-dependent manner. Furthermore, administration of SHA (1.5 mg/kg/day) from day 7 also reduced the urinary protein excretion on day 14 compared with that in saline and HA group. Conclusion: Our results suggest that SHA inhibits intraglomerular infiltration of macrophages, and prevents progression of experimental crescentic glomerulonephritis. Sulfated polysaccharides might be beneficial for the treatment of crescentic glomerulonephritis.
Effect of Congenital Heart Disease on Renal Function in Childhood
Authors: Agras Pınar Isik , Derbent Murat , Ozcay Figen , Baskin Esra , Turkoglu Suna , Aldemir Derya , Tokel Kurşat , Saatci Umit
Published: January 2005

Background: Nephropathy is a well-known complication of congenital heart disease (CHD), and the risk of developing renal impairment is particularly high in patients with cyanotic CHD. Most investigations of renal impairment in CHD have involved patients 20 years and older. This study investigated renal tubule function in pediatric patients with CHD, and compared findings in cyanotic and acyanotic groups. Methods: Twenty children with acyanotic CHD, 23 children with cyanotic CHD, and 13 healthy children were enrolled. Blood and early morning urine samples were collected from each subject to measure urinary concentrations of sodium, microalbumin, creatinine, β2-microglobulin, and N-acetyl-β-D-glucosaminidase (NAG). Results: The age and sex distributions in the three groups were similar. Median fractional excretion of sodium (FeNa) and urinary NAG/creatinine were significantly higher in the cyanotic group than in the control group (p = 0.022 and p = 0.002, respectively). There were no statistically significant differences among the groups with respect to urinary β2-microglobulin/creatinine, urinary microalbumin/creatinine or glomerular filtration rate. Conclusion: Tubular injury can be detected before glomerular injury occurs even within the first decade of life in patients with cyanotic CHD.
Selection of Dilutional Method for On-Line HDF, Pre- or Post-Dilution
Authors: Masakane Ikuto
Published: January 2005

Post- and pre-dilution methods equally have advantages and disadvantages, therefore we should choose the more favorable one for clinical use. However, it still remains controversial which technique is better in on-line HDF. In post-dilution, the clearances of small molecular uremic toxins increase as well as low molecular proteins, however the risk of albumin leakage caused by high transmembranous pressure (TMP) also increases. We can avoid the risk of albumin leakage because there are several maneuvers which aid in avoiding an increase of TMP, such as glucose infusion and gradual control of Qf. On the other hand, the pre-dilution method is rather safe in the risk of albumin leakage but has an obvious clearance loss of small molecular substances caused by a decreased dialysate flow rate. The influence of microbial contamination and acetate are rather severe in pre-dilution on-line HDF. These lines of evidence suggest that post-dilution on-line HDF is the best choice for treating chronic HD patients.
Clinical Benefit of Preserving Residual Renal Function in Patients after Initiation of Dialysis
Authors: Kuno Tsutomu , Matsumoto Kouichi
Published: January 2005

Preserving residual renal function (RRF) after initiation of dialysis therapy is desirable for improving quality of life in ESRD patients. It has been believed that RRF declines more slowly in patients receiving continuous ambulatory peritoneal dialysis (CAPD) than in patients treated with other forms of maintenance dialysis. Episodes of intravascular volume depletion might be expected to cause more rapid loss of RRF, and are more frequent in patients on hemodialysis, which is intermittent therapy. However, recently it was demonstrated that in hemodialysis using high-flux biocompatible membrane and ultrapure water, RRF declines at a rate indistinguishable from that in CAPD. The HDF using ultrapure dialysate and the substitution fluid may show to preserve RRF as well as CAPD patients. In future, it might be a major concern for the assessment of the HDF by a multicenter clinical study for preserving RRF.
Suitability of Acoustic Perturbation Measures in Analysing Periodic and Nearly Periodic Voice Signals
Authors: Ma Estella P.-M. , Yiu Edwin M.-L.
Published: January 2005

In recent years, acoustic perturbation measurement has gained clinical and research popularity due to the ease of availability of commercial acoustic analysing software packages in the market. However, because the measurement itself depends critically on the accuracy of frequency tracking from the voice signal, researchers argue that perturbation measures are not suitable for analysing dysphonic voice samples, which are aperiodic in nature. This study compares the fundamental frequency, relative amplitude perturbation, shimmer percent and noise-to-harmonic ratio between a group of dysphonic and non-dysphonic subjects. One hundred and twelve dysphonic subjects (93 females and 19 males) and 41 non-dysphonic subjects (35 females and 6 males) participated in the study. All the 153 voice samples were categorized into type I (periodic or nearly periodic), type II (signals with subharmonic frequencies that approach the fundamental frequency) and type III (aperiodic) signals. Only the type I (periodic and nearly periodic) voice signals were acoustically analysed for perturbation measures. Results revealed that the dysphonic female group presented significantly lower fundamental frequency, significantly higher relative amplitude perturbation and shimmer percent values than the non-dysphonic female group. However, none of these three perturbation measures were able to differentiate between male dysphonic and male non-dysphonic subjects. The noise-to-harmonic ratio failed to differentiate between the dysphonic and non-dysphonic voices for both gender groups. These results question the sensitivity of acoustic perturbation measures in detecting dysphonia and suggest that contemporary acoustic perturbation measures are not suitable for analysing dysphonic voice signals, which are even nearly periodic.
Entwicklung und Erprobung des Heidelberger Vorschulscreenings zur auditiven Wahrnehmung und Sprachverarbeitung (HVS)
Authors: Brunner Monika , Pfeiffer Barbara , Heinrich Christine , Pröschel Ute
Published: January 2005

Für die Diagnostik auditiver Wahrnehmung und der Sprachverarbeitung im Vorschulalter fehlten bis jetzt standardisierte deutschsprachige Verfahren. Die Entwicklung eines standardisierten Screenings sollte diese diagnostische Lücke schliessen.Die Endform des Verfahrens wurde an 180 Kindern aus 15 Kindergärten erprobt, statistisch analysiert und auf die Gütekriterien hin untersucht. Das Screening enthält folgende 7 Untertests: auditive Merkspanne, expressive Anlautanalyse, Silben segmentieren, phonematische Differenzierung, Artikulomotorik, Wortfamilien erkennen, Reime erkennen. Die Ergebnisse zeigten, dass Reliabilität und Objektivität gewährleistet sind. Der Extremgruppenvergleich ergab, dass Kinder mit Auffälligkeiten der Artikulation, des Wortschatzes, der Hörleistungen und solche mit mangelnder Schulreife signifikant schlechtere Leistungen im HVS erbrachten als Kinder ohne diese Probleme. Der Test erlaubt Kinder mit Sprachverarbeitungsstörungen rechtzeitig vor der Einschulung zu identifizieren.
Osteopontin Distribution in the Canine Skeleton during Growth and Structural Maturation
Authors: Schnapper Anke , Meyer Wilfried
Published: January 2005

The distribution of osteopontin (OPN) was studied immunohistochemically in cells and extracellular matrix in the humerus, scapula, and lumbar vertebrae of growing (age: 6 weeks, 12 weeks, 4.5 months) and adult dogs. OPN was expressed in hypertrophic chondrocytes of epiphyseal cartilage and in chondrocytes of the deep zone of mature articular cartilage, where extracellular matrix was also stained. OPN expression was strongest in 4.5-month-old puppies in cells of the osteoblastic lineage. It also varied with microlocation and was pronounced in areas prone to resorption due to modelling and remodelling activities. Osteoclasts were always strongly labelled with OPN. OPN deposition in extracellular bone matrix was detected particularly as a delineation of cartilage cores within secondary trabeculae and as a lining of the trabecular surfaces in resorption microlocations. The OPN distribution pattern is discussed here for each cell population with regard to its functional implications.
Differential Expression of Tissue Inhibitor of Matrix Metalloproteinases 3 in Uveal Melanoma
Authors: Nareyeck Gordon , Zeschnigk Michael , von der Haar Daniela , Schilling Harald , Bornfeld Norbert , Anastassiou Gerasimos
Published: January 2005

Based on gene profiling, two entities of uveal melanomas exist. So far, these two entities can be distinguished by the chromosome 3 status which strongly associates with the metastatic potential of the tumours. Reorganization of the extracellular matrix is one of the steps towards dissemination of tumour cells. In the present study, we examined the tissue inhibitor of matrix metalloproteinases (TIMP) 3 expression in 19 uveal melanomas and compared the results with histopathological and genetic features. The expression level of TIMP-3 mRNA as determined by microarray analysis was associated with the chromosome 3 status of the tumour (p = 0.003). All tumours with disomy 3 showed moderate to high expression of TIMP-3 mRNA, whereas TIMP-3 was highly expressed in one tumour, less expressed in 3 tumours and absent in the remaining 6 tumours with monosomy 3. Immunohistochemistry for TIMP-3 was positive in 9/19 tumours, but only in 3 tumours were more than 5% of the tumour cells stained positive. There was no association between immunohistochemical detection of TIMP-3 and chromosome 3 status. In tumours with disomy 3, we found none or very few TIMP-3-positive cells though the mRNA level was high which indirectly postulates posttranscriptional problems in protein biosynthesis in this entity of uveal melanomas. There was a trend between TIMP-3 protein expression and both cell type (p = 0.11) and presence of loops and/or networks (p = 0.06) in tumour which may indicate a role of TIMP-3 in the biology of uveal melanoma.
Etiology and Outcome of Non-Immune Hydrops fetalis in Southern Thailand
Authors: Suwanrath-Kengpol Chitkasaem , Kor-anantakul Ounjai , Suntharasaj Thitima , Leetanaporn Roengsak
Published: January 2005

Objective: To study the etiology and outcome of non-immune hydrops fetalis in southern Thailand. Methods: The medical records and videotape recordings of all pregnant women diagnosed with non-immune fetal hydrops, from January 1993 to December 2002 were reviewed. Results: Non-immune hydrops fetalis was documented in 71 cases. The causes of fetal hydrops were identified in 87.3%. Homozygous α-thalassemia-1 dominated as the cause of non-immune fetal hydrops (28.2%), followed by structural abnormalities (15.5%) and infection (12.7%). The underlying etiology remained unknown in 9 cases (12.7%). The overall survival rate of non-immune hydrops fetalis cases was 4.2%. Spontaneous regression occurred in 2 cases. Two cases were lost to follow up after initial evaluation. Termination of pregnancy was performed in 47 cases. There were 12 dead fetuses in utero, 2 stillbirths, 5 early neonatal deaths and only 3 cases survived. Conclusions: Homozygous α-thalassemia-1 is the most common cause of non-immune hydrops fetalis in southern Thailand, and the overall prognosis of non-immune hydrops fetalis is poor. We suggest that an effective thalassemia-screening program for prevention and control of homozygous α-thalassemia-1 be established in all areas where the α-thalassemia-1 gene is prevalent.
Recombinant Adeno-Associated Virus Vector Expressing Angiostatin Inhibits Preretinal Neovascularization in Adult Rats
Authors: Lai Chi-Chun , Wu Wei-Chi , Chen Show-Li , Sun Ming-Hui , Xiao Xiao , Ma Lih , Lin Keng-Kuo , Tsao Yeou-Ping
Published: January 2005

Clinically, preretinal neovascularization (PNV) induced by vessel occlusion is one of the leading causes to induce blindness. The present study was designed to determine if a recombinant adeno-associated viral vector expressing mouse angiostatin (rAAV-angiostatin) can inhibit experimental PNV in an adult Sprague-Dawley rat model. rAAV-angiostatin and rAAV-lacZ were delivered by intravitreal injections to the right and left eyes of rats. Transgenetic expression of angiostatin in the retina was determined by reverse-transcriptase polymerase chain reaction (RT-PCR). PNV was established by rose-bengal-assisted laser-induced retinal vein occlusion 21 days after the viral injections. The total number and sizes of the neovascular tufts were analyzed 14 days after venous occlusion using retinal flat mount by fluorescein-isothiocyanate-dextran angiography. Electroretinograms (ERGs) were recorded to study any possibility of retinal toxicity of rAAV-angiostatin 3 months after the injections. Angiostatin gene expression in the retina was detectable by RT-PCR, and ERG analysis showed no reduction of b-waves in the rAAV-angiostatin-injected eyes. The number and size of neovascular tufts were significantly lower in rAAV-angiostatin-injected eyes (p = 0.001) than controls. These findings indicated that rAAV-angiostatin successfully suppressed experimental PNV, and no retinal toxicity of the rAAV-angiostatin injection was observed according to ERG recordings.
Inhibitory Effects of Clofilium on Membrane Currents Associated with Ca2+ Channels, NMDA Receptor Channels and Na+, K+-ATPase in Cortical Neurons
Authors: Yang Aizhen , Wang Xue Qing , Sun Chuan-Shu , Wei Ling , Yu Shan Ping
Published: January 2005

The class III antiarrhythmic agent 4-chloro-N,N-diethyl-N-heptyl-benzene butanaminium (clofilium) is known as a K+ channel open-channel blocker and has either anti- or proapoptotic property due to undefined mechanisms. Based on the evidence that neuronal viability is largely, sometimes critically, affected by voltage- and ligand-gated Ca2+ channels and the Na+, K+-ATPase, we tested the hypothesis that clofilium might additionally act on Ca2+ permeable ion channels and the Na+, K+-ATPase. Membrane currents associated with activities of voltage-gated Ca2+ channels, N-methyl-D-aspartate (NMDA) receptor channels and Na+, K+-ATPase were recorded using whole-cell recordings in cultured murine cortical neurons. Clofilium (0.1–100 µmol/l) inhibited high voltage-activated Ca2+ currents in concentration- and use-dependent manners. Clofilium acted as a potent antagonist of NMDA receptor channels, preferably blocked the NMDA steady-state current at a low concentration (0.1 µmol/l). At concentrations of >100 µmol/l, clofilium blocked both peak and steady-state NMDA currents in a voltage-independent manner. Clofilium also inhibited the Na+, K+-ATPase current with an IC50 of 7.5 µmol/l. Our data suggest that the pharmacological action of clofilium is far more complex than recognized before; the multiple actions of clofilium on membrane conductance may explain its diverse effects on cellular events and cell viability.
Subcutaneous Nephrovesical and Nephrocutaneous Bypass
Authors: Jurczok A. , Loertzer H. , Wagner S. , Fornara P.
Published: January 2005

Objective: We evaluated the effectiveness of the subcutaneous bypass for ureteral obstruction in patients with advanced malignancies. Two versions of the minimally invasive technique were performed: nephrovesical and nephrocutaneous bypass. Methods: A specially designed composite implant consisting of an inner smooth silicone-covered tube covered by a coiled e-PTFE-tube was used in 14 patients. Results: 10 subcutaneous nephrovesical bypasses were inserted in 10 patients, 8 nephrocutaneous bypasses in 4 patients. During the mean follow-up period of 13.1 months complications were observed in 2 patients with nephrocutaneous bypass, one encrustation and one infection of the bypass system. Conclusions: The subcutaneous nephrovesical and nephrocutaneous bypass is a safe alternative for palliative treatment of ureteral obstruction caused by pelvic malignancy.
Transvaginal Ultrasonography and Endometrial Cytology as a Diagnostic Schema for Endometrial Cancer
Authors: Minagawa Yukihisa , Sato Shinya , Ito Masayuki , Onohara Yoshimasa , Nakamoto Shu , Kigawa Junzo
Published: January 2005

Objective: To determine whether the combined use of transvaginal ultrasonography and endometrial cytology is an effective diagnostic schema for endometrial cancer and hyperplasia of the uterus. Methods: Five hundred fifty-two women were enrolled in this study. For all subjects, endometrial thickness was evaluated by transvaginal ultrasonography. Endometrial cytology was carried out according to the following criteria: all women with atypical uterine bleeding, for asymptomatic postmenopausal women with endometrial thickness ≧5 mm, and for asymptomatic premenopausal women with endometrial thickness ≧20 mm. When the cytological findings were abnormal, we performed a hysteroscopy-guided biopsy within 2 weeks. Women who received transvaginal ultrasonography alone, or those who showed negative cytology, underwent repeated gynecological examination and transvaginal ultrasonography 3, 6, and 12 months after the first examination. Results: Endometrial cytology was done on 129 women (23.4% of all subjects), of whom 14 were diagnosed as ‘positive’ cytology, 20 as ‘suspicious positive’, and 95 as ‘negative’. A total of 34 women with ‘positive’ or ‘suspicious positive’ cytological result underwent hysteroscopy-guided endometrial biopsy. The histological diagnosis of the endometrium included 13 endometrial cancers, 9 endometrial hyperplasias (one atypical hyperplasia and 3 hyperplastic polyps), and 10 normal endometria. As a diagnostic schema for endometrial cancer, this combined method resulted in 100% sensitivity, 99.1% specificity, 92.9% positive predictive value, and 100% negative predictive value. For endometrial hyperplasia, the method resulted in 100% sensitivity, 89.6% specificity, 40.0% positive predictive value, and 100% negative predictive value. Conclusion: A combination of transvaginal ultrasonography and endometrial cytology may be an effective diagnostic schema for endometrial cancer and hyperplasia.
Protective Effects of Insulin during Ischemia-Reperfusion Injury in Hamster Cheek Pouch Microcirculation
Authors: Colantuoni A. , Lapi D. , Paterni M. , Marchiafava P.L.
Published: January 2005

Objective: The effects of insulin (0.18 nM–0.18 µM) on reduced capillary perfusion, microvascular permeability increase and leukocyte adhesion induced by ischemia-reperfusion injury were investigated in the hamster cheek pouch microcirculation. To gain insight into the insulin’s mechanism of action, the effects of its higher concentration (0.18 µM) were investigated after inhibition of tyrosine kinase (TK), nitric oxide synthase (NOS), protein kinase C (PKC), phosphatidylinositol 3-kinase and K+(ATP) channels, alone or in combination. Two concentrations for each inhibitor were used. Methods: Microcirculation was visualized by fluorescence microscopy. Perfused capillary length, microvascular permeability, leukocyte adhesion to venular walls, vessel diameter and capillary red blood cell velocity were assessed by computer-assisted methods. Measurements were made at baseline (B), after 30 min of ischemia (I), and after 30 min of reperfusion (R). Results: In control animals, perfused capillary length decreased by 63 ± 5% of baseline at R. Microvascular permeability increased at I and R, while leukocyte adhesion was most pronounced in V1 postcapillary venules at R. Insulin dose-dependently preserved capillary perfusion at R (–28 ± 6 and –15 ± 6% of baseline), but was unable to prevent the increase in permeability at I (0.25 ± 0.05 and 0.29 ± 0.06 Normalized Grey Levels, NGL) and R (0.49 ± 0.10 and 0.53 ± 0.09 NGL), according to the concentrations. Adhesion of leukocytes was observed mostly in V3 venules at R (9 ± 2 and 10 ± 2/100 µm venular length, with the lower and higher concentration, respectively). Nitric oxide synthase inhibition by NG-nitro-L-arginine-methyl ester prior to insulin did not affect capillary perfusion at R (–18 ± 3% of baseline with higher concentration), but prevented permeability increase (0.20 ± 0.04 NGL, according to higher concentration) and reduced leukocyte adhesion in V3 venules at R (1.5 ± 1.0/100 µm of venular length, with higher concentration). Blockade of K+(ATP) channels by glibenclamide prior to insulin decreased perfused capillary length at R (–58 ± 6% of baseline with higher concentration), attenuated leakage at R (0.30 ± 0.04 NGL, according to higher concentration) and caused leukocyte adhesion mainly in V1 venules at R (9.0 ± 1.5/100 µm of venular length, with higher concentration). Inhibition of either TK, PKC or phosphatidylinositol 3-kinase did not affect microvascular responses to insulin. Simultaneous inhibition of TK and NOS did not increase protection. Conclusions: Insulin prevents ischemia-reperfusion injury by promoting capillary perfusion through an apparent activation of K+(ATP) channels and increase in nitric oxide release.
Effects of Flow Patterns on the Localization and Expression of VE-Cadherin at Vascular Endothelial Cell Junctions: In vivo and in vitro Investigations
Authors: Miao Hui , Hu Ying-Li , Shiu Yan-Ting , Yuan Suli , Zhao Yihua , Kaunas Roland , Wang Yingxiao , Jin Gang , Usami Shunichi , Chien Shu
Published: January 2005

Atherosclerosis occurs preferentially at vascular curvature and branch sites where the vessel walls are exposed to fluctuating shear stress and have high endothelial permeability. Endothelial permeability is modulated by intercellular adhesion molecules such as VE-cadherin. This study was designed to elucidate the effects of different flow patterns on the localization and expression of VE-cadherin in endothelial cells (ECs) both in vivo and in vitro. VE-cadherin staining at EC borders was much stronger in the descending thoracic aorta and abdominal aorta, where the pulsatile flow has a strong net forward component than in the aortic arch and the poststenotic dilatation site beyond an experimental constriction, where the flow near the wall is complex and reciprocating with little net flow. With the use of flow chambers the effects of pulsatile flow (12 ± 4 dyn/cm2 at 1 Hz) and reciprocating flow (0.5 ± 4 dyn/cm2 at 1 Hz) on VE-cadherin organization in endothelial monolayers were studied in vitro. VE-cadherin staining was continuous along cell borders in static controls. Following 6 h of either pulsatile or reciprocating flow, the VE-cadherin staining at cell borders became intermittent. When the pulsatile flow was extended to 24, 48 or 72 h the staining around the cell borders became continuous again, but the staining was still intermittent when the reciprocating flow was similarly extended. Exposure to pulsatile or reciprocating flow for 6 and 24 h neither change the expression level of VE-cadherin nor its distribution between membrane and cytosol fractions as determined by Western blot and compared with static controls. These findings suggest that the cell junction remodeling induced by different flow patterns may result from a redistribution of VE-cadherin within the cell membrane. Both the in vivo and in vitro data indicate that pulsatile and reciprocating flow patterns have different effects on cell junction remodeling. The lack of junction reorganization in regions of reciprocating flow in vivo and in vitro may provide a mechanistic basis for the high permeability and the preferential localization of atherosclerosis in regions of the arterial stress with complex flow patterns and fluctuating shear stress.
Cytochrome P450-2C11 mRNA Is Not Expressed in Endothelial Cells Dissected from Rat Renal Arterioles
Authors: Heil Sandra G. , De Vriese An S. , Kluijtmans Leo A.J. , Dijkman Henry , van Strien Denise , Akkers Robert , Blom Henk J.
Published: January 2005

Background: Cytochrome P450 (CYP) isoenzymes (CYP2C and CYP2J) are involved in the production of epoxyeicosatrienoic acids, which are postulated as endothelium-derived hyperpolarizing factors (EDHFs). We hypothesized that if CYP2C11 is involved in the EDHF-mediated responses, its mRNA should be expressed in endothelial cells. We, therefore, examined the mRNA expression of CYP2C11 in endothelial cells of renal arterioles. Methods: Laser microdissection was applied to isolate endothelial cells from the renal arterioles of 4 male and 4 female Wistar rats. As a positive control of CYP2C11 expression, hepatocytes were also dissected from these rats. RNA was isolated and real-time quantitative polymerase chain reaction (Q-PCR) analysis was applied. Results: Q-PCR analysis showed that CYP2C11 mRNA was not expressed in laser microdissected endothelial cells of renal arterioles of male and female rats. CYP2C11 mRNA expression was highly abundant in hepatocytes dissected from male livers, but in female livers hardly any CYP2C11 mRNA was detected. Conclusion: We have shown that endothelial cells can be dissected from small renal arterioles by laser microdissection to study the mRNA expression of specific genes by Q-PCR. Using this novel tool, we demonstrated that the CYP2C11 mRNA was not expressed in the endothelial cells of renal arterioles. Therefore, we speculate that CYP2C11 does not contribute to the EDHF-mediated responses in renal arterioles.
Volumetric Resection Using the SurgiScope®: A Quantitative Accuracy Analysis of Robot-Assisted Resection
Authors: Amin Devin Vikram , Lunsford L. Dade
Published: January 2005

Objective: This study evaluates the hypothesis that current image guidance technology can effectively guide the resection of a predefined intracranial volume from the surgical field in the absence of a visually distinct lesion. Methods: An in vitro model was constructed to simulate the resection of a visually nondistinct lesion. Preoperative CT was acquired, and the lesion was resected from the model with a cavitating ultrasonic aspirator using image guidance information provided by the SurgiScope® system. Results: On average, 77% of the 8.2-cm3 surgical target volume was removed. Over a series of 5 trials, the underresection volume was 1.9 cm3 on average or 23% of the surgical target volume. The overresection volume was 1.0 cm3 on average, representing 13% of the surgical target volume. Conclusion: This in vitro model developed to evaluate the accuracy and limitations of our current image guidance technology provided quantitative data to demonstrate the potential for robotic navigation systems to guide the volumetric resection in the absence of visual differentiation between the lesion and the surrounding brain.
C-106T Polymorphism in Promoter of Aldose Reductase Gene Is a Risk Factor for Diabetic Nephropathy in Type 2 Diabetes Patients with Poor Glycaemic Control
Authors: Gosek Katarzyna , Moczulski Dariusz , Zukowska-Szczechowska Ewa , Grzeszczak Wladyslaw
Published: January 2005

Background: Excessive flux through the polyol pathway has long been thought to be involved in the pathogenesis of diabetic microvascular complications. Aldose reductase (AR) is the first and rate-limiting enzyme in the pathway that catalyses the reduction of glucose to sorbitol. A frequent C-106T polymorphism in the promoter of the AR gene has been described, which may change the expression of the gene. The aim of the study was to examine if the C-106T polymorphism was associated with diabetic nephropathy. Material and Methods: We collected 444 patients with type 2 diabetes and divided them into three groups according to the renal status: 162 patients with normoalbuminuria, 153 with microalbuminuria and 129 with persistent proteinuria. Each subject was genotyped for the C-106 polymorphism using the PCR-based RFLP protocol. Results: When the whole study population was analysed, no distortion in the genotype frequency among the study groups was observed. When we stratified the study population by HbA1c we found that in patients with HbA1c ≧9% (median) the CT and TT genotypes were more frequent in patients with diabetic nephropathy (proteinuria and microalbuminuria) than those with normoalbuminuria (OR 2.04, 95% CI 1.12–3.74). Conclusion: The C-106T polymorphism in the AR gene is a risk factor for development of diabetic nephropathy in type 2 diabetes in patients with poor glycaemic control.