bluuebunny/crossref_metadata_2025 huggingface dataset:
INFLUENCE ON RHEOLOGY OF STATIC AND DYNAMIC STRUCTURES IN MODEL MAGNETORHEOLOGICAL FLUIDS
Authors: CHAKER MUSTAPHA , BRESLIN NEAL , LIU JING
Published: January 2005

This paper investigates the influence of static and dynamic structures on Rheology in a model magnetorheological fluid. Dynamic structures generated under shear are studied using first a rotational rheometer then an optical image processing system. A microscope allowed us to visualize the different patterns thus generated and compare these results to the measurements obtained with the rheometer. It also enabled us to analyze the various initial static structures formed by an externally applied magnetic field. Besides the well known column-dominated and bent-wall dominated static structures we were able to observe novel, concentric, ring like formations under shear. A dynamic yield stress analysis was conducted for each type of structure along with a statistical approach to further characterize and differentiate the various types of magnetic particle arrangements.
ELECTRORHEOLOGICAL BEHAVIOR OF CHITOSAN DERIVATIVE SUSPENSIONS
Authors: Choi Ung-su , Ahn Byeng-gil , Kwon Oh-kwan
Published: January 2005

The electrorheological (ER) behavior of chitosan and chitosan phosphate suspensions in silicone oil was investigated. Chitosan and chitosan phosphate suspensions showed a typical ER response (Bingham flow behavior) upon application of an electric field. However, chitosan phosphate suspension exhibited excellent shear yield stress compared with chitosan suspension. The difference in behavior results from the difference in the conductivity of the chitosan and chitosan phosphate particles due to their degree of the polarizability. The shear stress for chitosan and chitosan phosphate suspensions showed a linear dependence on the volume fraction of particles. The values of structure factor, A s obtained 1 and 3~4 for chitosan and chitosan phosphate suspensions and it may be due to the formation of single-row chains and multiple chains upon application of the electric field. Throughtout the experimental results, chitosan and chitosan phosphate suspensions were shown to be an ER fluid.
DOUBLE REFRACTION PHENOMENON OF ELECTRORHOLOGICAL FLUIDS
Authors: Zhao Xiaopeng , Qu Changzhen , Ma Yun
Published: January 2005

In this paper, the adjustable double refraction phenomenon of Electrorhological fluids (ERF) was investigated. The measurements have been made of He-Ne laser through suspension of silica and pentaerythrite in silicone oil. When electric field was applied perpendicular to the laser beam, it was found that no light gets through the pair of perpendicular polarizing plate and analyzer plate without electric field. But when ERF is brought to bear electric field, the transmission light intensity increases with the electric field to be rising. For ERF of the same material, the double refraction phenomenon is more obviously to the low concentration. It is thought that the double refraction phenomenon of ERF is due to the fact that the particles link together to form thin chains or thick columns.
Sphingosine 1-phosphate protects mouse extensor digitorum longus skeletal muscle during fatigue
Authors: Danieli-Betto Daniela , Germinario Elena , Esposito Alessandra , Megighian Aram , Midrio Menotti , Ravara Barbara , Damiani Ernesto , Libera Luciano Dalla , Sabbadini Roger A. , Betto Romeo
Published: January 2005

Sphingomyelin derivatives exert various second messenger actions in numerous tissues. Sphingosine (SPH) and sphingosine 1-phosphate (S1P) are two major sphingomyelin derivatives present at high levels in blood. The aim of the present work was to investigate whether S1P and SPH exert relevant actions in mouse skeletal muscle contractility and fatigue. Exogenous S1P and SPH administration caused a significant reduction of tension decline during fatigue of extensor digitorum longus muscle. Final tension after the fatiguing protocol was 40% higher than in untreated muscle. Interestingly, N, N-dimethylsphingosine, an inhibitor of SPH kinase (SK), abolished the effect of supplemented SPH but not that of S1P, suggesting that SPH acts through its conversion to S1P. Moreover, SPH was not effective in Ca2+-free solutions, in agreement with the hypothesis that SPH action is dependent on its conversion to S1P by the Ca2+-requiring enzyme SK. In contrast to SPH, S1P produced its positive effects on fatigue in Ca2+-free conditions, indicating that S1P action does not require Ca2+ entry and most likely is receptor mediated. The effects of S1P could be ascribed in part to its ability to prevent the reduction (−20 mV) of action potential amplitude caused by fatigue. In conclusion, these results indicate that extracellular S1P has protective effects during the development of muscle fatigue and that the extracellular conversion of SPH to S1P may represent a rheostat mechanism to protect skeletal muscle from possible cytotoxic actions of SPH.
Dual effects of n-alcohols on fluid secretion from guinea pig pancreatic ducts
Authors: Hamada Hiroyuki , Ishiguro Hiroshi , Yamamoto Akiko , Shimano-Futakuchi Sachiko , Ko Shigeru B. H. , Yoshikawa Toshiyuki , Goto Hidemi , Kitagawa Motoji , Hayakawa Tetsuo , Seo Yoshiteru , Naruse Satoru
Published: January 2005

Ethanol strongly augments secretin-stimulated, but not acetylcholine (ACh)-stimulated, fluid secretion from pancreatic duct cells. To understand its mechanism of action, we examined the effect of short-chain n-alcohols on fluid secretion and intracellular Ca2+ concentration ([Ca2+]i) in guinea pig pancreatic ducts. Fluid secretion was measured by monitoring the luminal volume of isolated interlobular ducts. [Ca2+]i was estimated using fura-2 microfluorometry. Methanol and ethanol at 0.3–10 mM concentrations significantly augmented fluid secretion and induced a transient elevation of [Ca2+]i in secretin- or dibutyryl adenosine 3′,5′-cyclic monophosphate (DBcAMP)-stimulated ducts. However, they failed to affect fluid secretion and [Ca2+]i in unstimulated and ACh-stimulated ducts. In contrast, propanol and butanol at 0.3–10 mM concentrations significantly reduced fluid secretion and decreased [Ca2+]i in unstimulated ducts and in ducts stimulated with secretin, DBcAMP, or ACh. Both stimulatory and inhibitory effects of n-alcohols completely disappeared after their removal from the perfusate. Propanol and butanol inhibited the plateau phase, but not the initial peak, of [Ca2+]i response to ACh as well as the [Ca2+]i elevation induced by thapsigargin, suggesting that they inhibit Ca2+ influx. Removal of extracellular Ca2+ reduced [Ca2+]i in duct cells and completely abolished secretin-stimulated fluid secretion. In conclusion, there is a distinct cutoff point between ethanol (C2) and propanol (C3) in their effects on fluid secretion and [Ca2+]i in duct cells. Short-chain n-alcohols appear to affect pancreatic ductal fluid secretion by activating or inhibiting the plasma membrane Ca2+ channel.
A rapid and efficient PCR-based mutagenesis method applicable to cell physiology study
Authors: Ko Jae-Kyun , Ma Jianjie
Published: January 2005

PCR-based mutagenesis is a cornerstone of molecular biology and protein engineering studies. Herein we describe a rapid and highly efficient mutagenesis method using type IIs restriction enzymes. A template gene is amplified into two separate PCR fragments using two pairs of anchor and mutagenic primers. Mutated sequences are located near the recognition site of a type IIs restriction enzyme. After digestion of two fragments with a type IIs enzyme, exposed cohesive ends that are complementary to each other are then ligated together to generate a mutated gene. We applied this method to introduce multiple site-directed mutations in EGFP and Bcl-2 family genes and observed perfect mutagenesis efficiency at the desired sites. This efficient and cost-effective mutagenesis method can be applied to a wide variety of structural and functional studies in cell physiology.
Frequency encoding in renal blood flow regulation
Authors: Marsh Donald J. , Sosnovtseva Olga V. , Pavlov Alexey N. , Yip Kay-Pong , Holstein-Rathlou Niels-Henrik
Published: January 2005

With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation of the myogenic oscillation by TGF. Analysis by wavelet transforms of single-nephron blood flow confirms that both amplitude and frequency of the myogenic oscillation are modulated by TGF. We developed a double-wavelet transform technique to estimate modulation frequency. Median value of the ratio of modulation frequency to TGF frequency in measurements from 10 rats was 0.95 for amplitude modulation and 0.97 for frequency modulation, a result consistent with TGF as the modulating signal. The simulation predicted that the modulation was regular, while the experimental data showed much greater variability from one TGF cycle to the next. We used a blood pressure signal recorded by telemetry from a conscious rat as the input to the model. Blood pressure fluctuations induced variability in the modulation records similar to those found in the nephron blood flow results. Frequency and amplitude modulation can provide robust communication between TGF and the myogenic mechanism.
Wiener Kernels of Chinchilla Auditory-Nerve Fibers: Verification Using Responses to Tones, Clicks, and Noise and Comparison With Basilar-Membrane Vibrations
Authors: Temchin Andrei N. , Recio-Spinoso Alberto , van Dijk Pim , Ruggero Mario A.
Published: January 2005

Responses to tones, clicks, and noise were recorded from chinchilla auditory-nerve fibers (ANFs). The responses to noise were analyzed by computing the zeroth-, first-, and second-order Wiener kernels (h0, h1, and h2). The h1s correctly predicted the frequency tuning and phases of responses to tones of ANFs with low characteristic frequency (CF). The h2s correctly predicted the frequency tuning and phases of responses to tones of all ANFs, regardless of CF. Also regardless of CF, the kernels jointly predicted about 77% of the features of ANF responses to “frozen” samples of noise. Near-CF group delays of kernels and signal-front delays of responses to intense rarefaction clicks exceeded by 1 ms the corresponding basilar-membrane delays at both apical and basal sites of the chinchilla cochlea. This result, confirming that synaptic and neural processes amount to 1 ms regardless of CF, permitted drawing a map of basilar-membrane delay as a function of position for the entire length of the chinchilla cochlea, a first for amniotic species.
Interaction of Visual and Proprioceptive Feedback During Adaptation of Human Reaching Movements
Authors: Scheidt Robert A. , Conditt Michael A. , Secco Emanuele L. , Mussa-Ivaldi Ferdinando A.
Published: January 2005

People tend to make straight and smooth hand movements when reaching for an object. These trajectory features are resistant to perturbation, and both proprioceptive as well as visual feedback may guide the adaptive updating of motor commands enforcing this regularity. How is information from the two senses combined to generate a coherent internal representation of how the arm moves? Here we show that eliminating visual feedback of hand-path deviations from the straight-line reach (constraining visual feedback of motion within a virtual, “visual channel”) prevents compensation of initial direction errors induced by perturbations. Because adaptive reduction in direction errors occurred with proprioception alone, proprioceptive and visual information are not combined in this reaching task using a fixed, linear weighting scheme as reported for static tasks not requiring arm motion. A computer model can explain these findings, assuming that proprioceptive estimates of initial limb posture are used to select motor commands for a desired reach and visual feedback of hand-path errors brings proprioceptive estimates into registration with a visuocentric representation of limb position relative to its target. Simulations demonstrate that initial configuration estimation errors lead to movement direction errors as observed experimentally. Registration improves movement accuracy when veridical visual feedback is provided but is not invoked when hand-path errors are eliminated. However, the visual channel did not exclude adjustment of terminal movement features maximizing hand-path smoothness. Thus visual and proprioceptive feedback may be combined in fundamentally different ways during trajectory control and final position regulation of reaching movements.
Structural and Functional Modification of THP on Nitration: Comparison with Stone Formers THP
Authors: Pragasam Viswanathan , Kalaiselvi Periandavan , Subashini Balasubramanian , Sumitra Kamalanathan , Varalakshmi Palaninathan
Published: January 2005

Objective: The crucial steps involved in the lithogenic process are governed by the macromolecular components of urine, of which proteins play a major role. Structurally abnormal proteins have been reported to be present in the urine of stone formers. Free radical injury has come a long way in explaining some of the pathophysiological events of renal lithiasis. Thus, our present work was designed to study the impact of the potent oxidant peroxynitrite on the biochemical components of the urinary Tamm-Horsfall glycoprotein (THP). Materials and Methods: Nitration on THP was carried out using peroxynitrite (ONOO–). After nitration, biochemical components like thiols, S-nitrosothiol, hexose, hexosamine and sialic acid were determined and these factors were compared with those of stone formers and normal THP. Crystallization behavior of control, nitrated NS-THP and stone formers THP was studied. Results: There was a significant decrease in thiol, hexose, hexosamine and sialic acid contents in stone formers and nitrated NS-THP, when compared to that of the control THP. In contrast to this, S-nitrosothiol content was significantly increased in stone formers and nitrated NS-THP (p < 0.001) when compared with the control THP. NOx metabolites were significantly elevated in stone formers THP when compared with that of control THP. When subjected to CaOx crystallization, stone formers THP and nitrated NS-THP promoted both CaOx nucleation and aggregation, while normal THP was found to be an inhibitor of the above processes. Conclusion: From our results we conclude that nitration of THP could represent one of the prime events in modifying kinetic behavior of THP, thus converting THP into a heterogeneous nucleator of renal calculi formation.
Controversies and Issues in Hemodiafiltration Therapy
Authors: Man Nguyen Khoa
Published: January 2005

Hemodiafiltration appears to be the most effective technique of renal replacement therapy but several drawbacks are not counterbalanced by significant advantages. Although optimal transfer for both small and middle molecules can be achieved, there is no difference in mortality risk between HDF and HD patients. The infusion of a large amount of dialysate containing residual acetate of 2–7 mmol/l could lead to impaired cardiac contractile functions and carbonyl stress whereas loss of amino acids and water-soluble vitamins along with high UF rate could lead to malnutrition. Moreover, as substitution fluid is prepared on-line, contaminated fluid could be inadvertently infused to patients. Stringent maintenance rules are required for the production of sterile and non-pyrogenic dialysis solutions. Finally, daily hemodialysis could be the most promising mode of renal replacement therapy since it leads to a more stable ‘milieu interieur’ than other techniques whatever the mode of solutes removal when performed three times a week.
On-Line Hemodiafiltration as Routine Treatment of End-Stage Renal Failure: Why Pre- or Mixed Dilution Mode Is Necessary in On-Line Hemodiafiltration Today?
Authors: Canaud Bernard , Lévesque Renée , Krieter Detlef , Desmeules Simon , Chalabi Lofti , Moragués Hélène , Morena Marion , Cristol Jean-Paul
Published: January 2005

Hemodiafiltration (HDF) is a well-recognized treatment modality that offers a way of optimizing renal replacement therapy efficacy of end-stage renal disease (ESRD) patients. On-line production of substitution fluid by the ‘cold sterilization’ process (ultrafiltration) gives access to an unlimited amount of sterile and non-pyrogenic IV grade solution. This advantageous low-cost solution may therefore be employed to develop various forms of high-flux HDF modalities (ol-HDF). High-flux post-dilutional HDF (post-HDF) has mainly been used in clinical practice since it offers the most efficient and best compromise between diffusive and convective clearances. Nowadays, the new targets in anemia correction have created hemorheological conditions that render high filtration rate more difficult to achieve and/or at the expense of higher transmembrane pressure. To overcome this new challenging condition and keeping the same concept, it has been proposed to develop alternative modalities with various sites of fluid substitution (predilution, mixed pre-post with various percentages) in HDF. In this presentation we discuss the benefits of using pre-HDF and show how to match performances with post-HDF. Potential advantages of new ol-HDF options (pre-, mixed and mid-dilution) that are advocated have to be demonstrated in clinical trials. On-line HDF is a multipurpose treatment method that is employed to improve care and outcomes of ESRD patients. Due to its versatility, ol-HDF should be considered as a technical platform permitting to personalize and tailor treatment to patients’ needs. The mode of substitution (post-, pre-, mixed or mid-dilution) should be established according to hemorheological conditions of the individual patient.
New Trends in HDF Therapies: Validity of Internal Filtration-Enhanced Hemodialysis
Authors: Mineshima Michio
Published: January 2005

Internal filtration-enhanced hemodialysis (IFEHD), defined as HD therapy using a dialyzer designed for enhanced internal filtration, seems to be more convenient in comparison with HDF therapies. In this paper, the validity of IFEHD was discussed during an analytical study and experimental studies. As a result, the maximum internal filtration flow rate (QIF) value increased with a smaller inner diameter (D), a longer effective length (Leff), and a larger density ratio (DR) value of the hollow fibers. The validity of IFEHD was clarified by an analytical study and experimental studies. Development of a dialyzer with enhanced internal filtration, however, should take account of the patient’s safety, and hemolysis and endotoxin invasion form the dialysate to the patient should be avoided.
Features of Listeners Affecting the Perceptions of Mandarin Electrolaryngeal Speech
Authors: Liu Hanjun , Wan Mingxi , Wang Supin
Published: January 2005

The effect of age and gender of listeners on the perceptions of Mandarin electrolaryngeal speech was investigated. Sixty males and 40 females were categorized into five age groups (20–29, 30–39, 40–49, 50–59, and 60–70 years), who were regarded as naïve listeners for having no experience with electrolaryngeal speech. They were instructed to score acceptability of a passage and intelligibility of isolated words and embedded words. The results revealed no gender effects but significant age effects on the perceptual evaluation. It was more difficult for the 50–59 and 60–70 groups to understand electrolaryngeal speech. The results were also analyzed for tonal and segmental errors, and errors of tone alone were found to occur more often than segmental errors. In addition, a preliminary study was presented for the perceptions of the four Mandarin tones. Higher percent correct identification was found for the high-level tone compared to the other three tones.
Anxiety, Depression, and Quality of Life in Mothers of Children with Cleft Lip/Palate
Authors: Weigl Veronika , Rudolph Michael , Eysholdt Ulrich , Rosanowski Frank
Published: January 2005

Multidisciplinary care for patients with cleft lip and palate (CLP) includes the surgical correction of the facial disfigurement and the rehabilitation of functional deficits to optimize the communicational competence of the affected patient. Although the well-being of the mother of a CLP child is an important protective factor for the child, up to now literature has paid only little attention to this topic. In this study, 50 mothers of CLP children aged 1–10 years were examined using the 36-item Short-Form Health Survey and the Hospital Anxiety and Depression Scale (HADS) to screen for quality of life, anxiety and depression. Surprisingly, the data obtained indicate no group-specific alterations of these items when compared with normal controls. In cases with a deteriorated quality of life, the results of the HADS were pathologic as well. In general, mothers of CLP children aged more than 12 months do not require psychological screening. In individual cases, screening for relevant emotional aspects may be restricted to using the HADS.
Collagen Type I Increases Bone Remodelling around Hydroxyapatite Implants in the Rat Tibia
Authors: Rammelt Stefan , Schulze Eva , Witt Martin , Petsch Elisabeth , Biewener Achim , Pompe Wolfgang , Zwipp Hans
Published: January 2005

The early interface reaction of cancellous bone to a nanocrystalline hydroxyapatite (HA) cement containing 3 wt% collagen type I (HA/Coll) with a setting under physiological temperature and pH was observed using immunohistochemical techniques. Pure HA served as a control. Cylinders with a diameter of 2 mm were implanted into the proximal tibia of 72 adult Wistar rats. Histological sections of 6 animals were prepared after 1, 2, 4, 6, 14 and 28 days. First, osteoblast-like cells as well as a marked reaction for osteonectin, osteopontin and its ligand CD44 were observed as early as 2 days after implantation at the interface around HA/Coll implants. Further, reactivity for ED1 and cathepsin D, both markers for phagocytotic cells, appeared earlier and stronger around HA/Coll. In cell counts, a significantly higher average number of ED1- and cathepsin D-positive phagocytotic cells was observed around the HA/Coll implants on days 6 (p < 0.01), 14 and 28 (p < 0.05). The number of osteopontin-positive cells was significantly higher around HA/Coll implants at days 6 and 14 (p < 0.05). Two weeks after the implantation, first islands of newly formed woven bone were observed around the HA/Coll implant, but not around the control implant. The amount of direct bone contact after 28 days averaged 28% around pure HA and 51% around HA/Coll implants (p < 0.05). While both implants displayed a good osteoconductivity, a higher bone remodelling activity was observed around collagen-containing HA implants compared to pure HA implants. It appears that the addition of collagen to HA implants can enhance both phagocytotic and osteogenic processes. This may result in an earlier acceptance and better osseointegration of the HA/Coll implants into the surrounding tissue.
Schlemm’s Canal and the Collector Channels at Different Developmental Stages in the Human Eye
Authors: Ramírez José M. , Ramírez Ana I. , Salazar Juan J. , Rojas Blanca , De Hoz Rosa , Triviño Alberto
Published: January 2005

We studied Schlemm’s canal (SC) and other posttrabecular structures of aqueous humor outflow in eyes from human fetuses (at 24, 26, 33 and 36 weeks of gestation), eyes from normal children (2 months and 8 years old) and normal adult eyes, using mesoscopy/diaphanization and light microscopy. This study points to the presence of a collector canal parallel to the outer wall of SC (the outer collector). At 24 weeks of gestation, the SC was observable throughout the entire circumference (360°) and the anlage of the outer collector was present. At 26 weeks of gestation, the outer collector was still growing. At 33 weeks of gestation, the outer collector was parallel to the SC and had become visible in some sectors. At 36 weeks, the SC and the outer collector were clearly defined and connected by intercanal links. The intrascleral plexus was growing. At 2 months, the deep intrascleral plexus and the episcleral plexus continued to grow, developing by sectors. At 8 years of age, the same structures corresponded to those in adults. The outer collector and the intrascleral plexuses were divided into sectors not greater than 120°.
Final Consonants and Glottalization: New Perspectives from Hanoi Vietnamese
Authors: Michaud A.
Published: January 2005

The evolution from final obstruents to final glottal stop and then to rhymeglottalization (i.e. from /at/ to /aʔ/, then to /aˀ/) is a well-established general trendin the history of the Sino-Tibetan language family and beyond. It has further beenshown by laryngoscopy that in three languages which retain the nonreleasedsyllable-final obstruents /p/, /t/ and /k/ (Standard Thai, and two Chinese dialects),these obstruents are often accompanied by a glottal stop. The present researchraises the issue whether there is another typological possibility: can nonreleasedfinal obstruents be accompanied consistently by modal phonation, without glottalstop? Analysis of electroglottographic recordings of 126 syllables in two carriersentences spoken by 4 speakers shows that, in Hanoi Vietnamese, the final obstruents/p/, /t/ and /k/ are not accompanied by glottalization, and that the open quotientincreases in the course of the syllable rhyme. Obstruent-final rhymes (whichmay carry either of two tones: D1 or D2) are compared with nasal-final rhymeswhich, under one of the tones (tone B2), are confirmed to be glottalized. Our findingis that tones D1 and D2 (i.e. obstruent-final rhymes) are both produced inmodal voice, which shows that the typological paradigm of observed realizationsof syllable-final obstruents must be enlarged. The discussion puts forward thehypothesis that the unusual association of segments and voice quality found inHanoi Vietnamese is a strategy to maintain the opposition between B2-tone andD2-tone rhymes.
Wavelet Analysis of Cutaneous Blood Flow in Melanocytic Skin Lesions
Authors: Häfner Hans-Martin , Bräuer Kurt , Eichner Martin , Steins Anke , Möhrle Matthias , Blum Andreas , Jünger Michael
Published: January 2005

Laser Doppler flowmetry (LDF) is frequently used to study the microcirculation. Usually LDF time series are analyzed by conventional linear methods, mainly Fourier analysis. The aim of this study was to observe dynamic blood perfusion of the skin in malignant and benign melanocytic skin lesions. Wavelet transformation was performed on each LDF time series in order to calculate a vasomotion field. First, the differences in vasomotion between healthy and pigmented skin were evaluated visually on six different time scales of the vasomotion field. In order to quantify the findings, vasomotion scale variance (VSV) was calculated for each scale plane of the vasomotion field. These VSV were compared using contrast ΔVSV to determine the difference between healthy skin and a pigmented skin lesion in the same patient. After the measurements, the skin lesions were excised and examined histologically. We found that wavelet analysis of LDF time series is a specific, sensitive method for the in vivo identification of malignant melanoma. It is a non-invasive procedure and takes minimal time to be carried out.
Influence of Gender on Baseline Features and Clinical Outcomes among 17,370 Patients with Confirmed Ischaemic Stroke in the International Stroke Trial
Authors: Niewada Maciej , Kobayashi Adam , Sandercock Peter A.G. , Kamiński Bogumił , Członkowska Anna
Published: January 2005

Aim: We sought to determine whether there were differences between men and women with acute stroke in their baseline characteristics and outcome in a large cohort of patients randomized in the International Stroke Trial (IST). Methods: Of the 19,435 patients randomized in the IST, 17,370 had an ischemic stroke confirmed by CT scan or autopsy (8,003 female and 9,367 male). In males and females, we compared baseline characteristics (age, frequency of atrial fibrillation, pre-stroke administration of aspirin and systolic blood pressure, conscious level, stroke syndrome) and outcome at 14 days and 6 months (death, complications, dependency, recovery, place of residence). We developed a specific logistic regression model to adjust for case-mix in order to evaluate the separate influence of gender on outcome. Results: Female patients were older, suffered more frequently from atrial fibrillation, had higher systolic blood pressure at randomization and generally had more severe strokes (a higher proportion were unconscious or drowsy or had a total anterior circulation syndrome). Females had higher 14-day and 6-month case fatality and were more likely to be dead or dependent at six months (and consequently more likely to require institutional or residential care). Gender was an independent predictor of death or dependency at 6 months. Conclusions: The adverse effect of female gender on outcome indicates that further research to explore the underlying biological mechanism is justified, and that more intensive acute and long-term treatment may be needed to improve outcome among female patients with stroke.
Mortality Trends of Multiple Sclerosis in Spain, 1951–1997: An Age-Period-Cohort Analysis
Authors: Llorca Javier , Guerrero-Alonso Paula , Prieto-Salceda Dolores
Published: January 2005

Trends of multiple sclerosis mortality in Spain from 1951 to 1997 are examined. Age-adjusted mortality strongly decreased from 3.08 per 100,000 women in 1951–1967 to 0.59 in 1968–1980 (similar figures were obtained for men). This decrease seems to be due to an artifact produced by changes in codification of causes of death. An age-period-cohort analysis, limited to the period 1968–1997, showed that the mortality trend in Spain cannot be fully explained by year of death (period effect), but that a cohort (year of birth) effect is also necessary. An increase in mortality related with the cohort of birth was detected: people born after 1953 had double the risk of those born between 1938 and 1947, and four times the risk of those born between 1923 and 1932. Regarding the period effect, there is a decrease in mortality, probably due to improvements in life expectancy of multiple sclerosis patients.
Surgical Treatment of Peripheral Vertigo and Vertiginous Diseases
Authors: Göksu Nebil , Bayazıt Yıldırım A. , Yılmaz Metin , Bayramoğlu İsmet
Published: January 2005

Although our understanding of the mechanisms of vertigo and pathophysiology of vertiginous disorders has increased, diagnosis and treatment of various vertiginous diseases is challenging. The objective for the treatment of a vertiginous disease is to eliminate the underlying pathology either with maneuvers or drugs. In vertiginous diseases, surgery is performed either to eliminate the underlying pathologic event or to create stability in the incoming vestibular signals. It is not always possible to treat the underlying disease. Therefore, surgery is usually performed for the relief of vertigo. There are various surgical approaches used to treat a variety of vertiginous diseases. Selection of the approach depends on the type of vertiginous disease. This review mainly focuses on the current status and outcome of the surgeries used in the treatment of a variety of vertiginous diseases.
Successful Pregnancy and Delivery after Removal of Gonadotrope Adenoma Secreting Follicle-Stimulating Hormone in a 29-Year-Old Amenorrheic Woman
Authors: Sugita Tatsuya , Seki Katsuyoshi , Nagai Yuichiro , Saeki Naokatsu , Yamaura Akira , Ohigashi Sawako , Iwata Arifumi , Tatsuno Ichiro , Sekiya Souei
Published: January 2005

We report a case of ovarian hyperstimulation related to a gonadotroph adenoma in a 29-year-old woman. The patient presented with amenorrhea and large cystic ovaries. Her serum estradiol was markedly elevated (up to 31,100 pmol/l). Serum LH was low, but serum FSH and PRL were normal. Cranial magnetic resonance imaging study revealed a pituitary macroadenoma. After successful removal of the pituitary tumor, FSH, LH and estradiol normalized and fluctuated within normal ranges thereafter. The patient resumed regular cycles of menstruation and conceived spontaneously. During pregnancy, estradiol increased and FSH and LH decreased. The finding confirms restoration of negative feedback of estradiol on FSH and LH secretion. The pregnancy course was uneventful and enlargement of ovaries did not occur.
Interactive Role of Protein Kinase C-δ with Rho-Kinase in the Development of Cerebral Vasospasm in a Canine Two-Hemorrhage Model
Authors: Obara Kazuo , Nishizawa Shigeru , Koide Masayo , Nozawa Kayo , Mitate Ayako , Ishikawa Tomohisa , Nakayama Koichi
Published: January 2005

Background: We previously reported that protein kinase C (PKC)-δ was initially translocated from the cytosol to the membrane fraction (on day 4), followed by PKC-α, with the progression of cerebral vasospasm after subarachnoid hemorrhage (SAH) on day 7. Rho/Rho-kinase pathways have also been proposed to be involved in the vasospasm. Thus we investigated the interactive role of Rho-kinase and PKC in the development of cerebral vasospasm after SAH. Methods: The cerebral vasospasm was produced using a ‘two-hemorrhage’ canine model. The animals were treated with Y-27632, a Rho-kinase inhibitor, and rottlerin, a PKC-δ inhibitor, both injected into the cisterna magna. Results: Y-27632 inhibited the vasospasm, 20-kDa myosin light chain (MLC20) phosphorylation, and PKC-δ translocation after the second injection of autologous blood on day 4. In contrast, Y-27632 did not affect the vasospasm on day 7. Rottlerin also inhibited the vasospasm on day 4, but had no effect on MLC20 phosphorylation and RhoA translocation. The vasospasm was accompanied with the phosphorylation of caldesmon (CaD), an actin-linked regulatory protein, which was strongly attenuated by Y-27632 and rottlerin. The application of PKC-δ to skinned strips of isolated canine basilar arteries caused a contraction and an increase in CaD phosphorylation. Conclusion: The development of cerebral vasospasm after SAH (on day 4) is caused by at least two mechanisms: one involves MLC20 phosphorylation mediated by the inhibition of MLC20 phosphatase by Rho-kinase, and the other CaD phosphorylation mediated by the activation of PKC-δ by Rho-kinase, which results in the alleviation of the inhibition by CaD of myosin Mg2+-ATPase activity.
Establishment of Immortalized Human Glomerular Endothelial Cell Lines and Their Application
Authors: Harada Takashi , Batsford Stephen , Morioka Tetsuo , Yao Jian , Arakawa Masaaki , Gejyo Fumitake , Oite Takashi
Published: January 2005

Background: The experimental use of cultured endothelial cells derived from the microvasculature such as glomerular endothelial cells possesses many problems, including limited growth rates, heterogeneity and loss of specific cell properties dependent on culture passage. In this study, we attempted to establish immortalized, human glomerular endothelial cell (HGEC) lines. Methods: HGECs of up to 5 passages were transformed by infection with simian virus (SV)-40. After 4–6 weeks the surviving, foci-forming cells were harvested and cloned. Each cell line obtained was examined by immunofluorescence with antibodies to antigens specific for vascular endothelial cells. The expression of adhesion molecules on cells incubated with or without TNF-α was also examined by cellular ELISA. Results: Three of twelve cell lines obtained expressed SV40 large T-antigen and von Willebrand’s factor, as well as endothelial cell adhesion molecules including ICAM-1 (CD54), PECAM-1 (CD31) and E-selectin (CD62E). In these cells, ICAM-1 and E-selectin expression was up-regulated by TNF-α, as in native cultured HGEC. Conclusions: These cell lines maintain the morphologic and functional characteristics of HGEC even after 60 passages. Immortalized HGEC will be useful for research on glomerular cell biology and provide a standardized substrate for anti-endothelial cell antibody detection.
MR-Based Stereotactic Mesencephalic Tractotomy
Authors: Fountas Kostas N. , Lane Forrest J. , Jenkins Patrick D. , Smith Joseph R.
Published: January 2005

Introduction: Medically refractory pain related to cancer is a major indication for pain surgery. Stereotactic mesencephalic tractotomy (SMT) constitutes a widely accepted procedure in treating unilateral head and neck cancer pain. Material and Method: We report a case of a MRI-based right-sided SMT for treating intractable craniofacial pain, in a 38-year-old patient, related to a previously resected adenocystic carcinoma of the parotid gland. The patient had undergone an implantation of an intrathecal morphine/clonidine pump and subsequent radiofrequency cingulotomy with only temporary improvement. Prior to SMT the patient developed left-sided chest wall pain, secondary to metastasis, in addition to her left-sided facial, dysesthetic pain. The MRI-based SMT was performed with the assistance of a side-extruding monopolar electrode (Leibinger GmbH, Freiburg, Germany) for intraoperative, topographic mapping of the spinothalamic tract. Two lesions were made at 8 and 5 mm off the midline on the right side at the level of the superior colliculus at 70°C for 90 s with a 2 × 4 mm radiofrequency bipolar electrode (Leibinger GmbH). Results: The patient developed intraoperatively left-sided facial, bodily and extremity thermoanalgesia. She had an unremarkable postoperative course. No early proprioceptive or gaze deficits were noted. Her facial and truncal pain was well controlled with intrathecal morphine and clonidine at the preoperative dosology for 17 months. Left-sided upper extremity dysesthesia developed 15 months after the procedure. The patient expired 18 months after this procedure due to an extensive metastatic disease. Conclusions: The use of high-resolution MRI (MPRAGE) and side-extruding electrode represent technical maneuvers that could decrease the morbidity and further improve the long-term outcome of SMT in treating patients with chronic, medically refractory cancer pain, who have a likely survival time in the order of 1 year ± 6 months.
Chloride Channels and Endocytosis: New Insights from Dent’s Disease and ClC-5 Knockout Mice
Authors: Devuyst Olivier , Jouret François , Auzanneau Céline , Courtoy Pierre J.
Published: January 2005

Dent’s disease is a hereditary renal tubular disorder characterized by low-molecular weight (LMW) proteinuria, hypercalciuria and nephrolithiasis. The disease is due to mutations of ClC-5, a member of the family of voltage-gated CLC chloride channels. ClC-5 is expressed in part in cells lining the proximal tubule (PT) of the kidney, where it colocalizes with albumin-containing endocytic vesicles belonging to the receptor-mediated endocytic pathway that ensures efficient reabsorption of ultrafiltrated LMW proteins. Since progression along the endocytic apparatus requires endosomal acidification, it has been suggested that dysfunction of ClC-5 in endosomes may lead to inefficient reabsorption of LMW proteins and dysfunction of PT cells. Analysis of a ClC-5 knockout (KO) mouse model, displaying all the characteristic renal tubular defects of Dent’s disease, showed evidence of a severe LMW proteinuria. Cytochemical studies with the endocytic tracer, peroxidase, showed poor transfer into early endocytic vesicles, suggesting that impairment of receptor-mediated endocytosis in PT cells is the basis for the defective uptake of LMW proteins in patients with Dent’s disease. Endocytosis and processing of LMW proteins involve the multiligand tandem receptors, megalin and cubilin, that are abundantly expressed at the brush border of PT cells. Characterization of the endocytic defect in ClC-5 KO mice revealed that ligands of both megalin and cubilin were affected. The total kidney content of megalin and especially cubilin at the protein level was decreased but, more importantly, using analytical subcellular fractionation and quantitative immunogold labelling we demonstrated a selective disappearance of megalin and cubilin at the brush border of PT cells. These observations allowed us to conclude that defective protein endocytosis linked to ClC-5 inactivation is due at least in part to a major and selective loss of megalin and cubilin at the brush border, reflecting a trafficking defect in renal PT cells. These results improve our understanding of Dent’s disease, taken as a paradigm for renal Fanconi syndrome and nephrolithiasis, and demonstrate multiple roles for ClC-5 in the kidney. These studies also provided insights into important functions such as apical endocytosis, handling of proteins by renal tubular cells, calcium metabolism, and urinary acidification.
Changes in Aorta Alpha1-Adrenoceptor Number and Affinity during One Year of Streptozotocin-Induced Diabetes in Rats
Authors: Schulingkamp Robert J. , Aloyo Vincent , Tallarida Ronald J. , Raffa Robert B.
Published: January 2005

α1-Adrenoceptor function and density in isolated thoracic aorta were measured during the course of streptozotocin-induced diabetes in rats. Diabetes was induced by a single tail vein injection of streptozotocin (60 mg/kg) and was verified by four measures (blood glucose level, increase in food intake, increase in water intake, and characteristic weight changes). Diabetes produced a significant increase in isolated aorta sensitivity to α1-adrenoceptor activation, manifested as a significant (p < 0.05) decrease in theA50 value for phenylephrine and an increase in the A50 (control)/A50 (diabetic) ratio (1.2, 1.7, and 2.0, respectively) with increasing length of diabetes (4, 12 and 52 weeks). There was a large and biphasic change in receptor density (Bmax), without a significant change (p > 0.05) in either agonist (phenylephrine) or antagonist (prazosin) affinities (KA and pA2 values, respectively). These results suggest compensatory mechanisms in receptor number and abnormalities in 2nd messenger transduction and can help direct efforts for improving antihypertensive or other pharmacological therapy for diabetic patients.
Tissue-Specific Expression of Renin-Angiotensin System Components in IgA Nephropathy
Authors: Miyake-Ogawa Chie , Miyazaki Masanobu , Abe Katsushige , Harada Takashi , Ozono Yoshiyuki , Sakai Hideto , Koji Takehiko , Kohno Shigeru
Published: January 2005

Background: The renin-angiotensin II system (RAS) has been implicated in the development of glomerulonephritis. The aims of this study were to determine (1) the expression of RAS components, angiotensin (Ang II)-forming enzymes [angiotensin-I-converting enzyme (ACE) and chymase], and Ang II receptors, and (2) the correlation between RAS expression and severity of tissue injury in IgA nephropathy (IgAN). Methods: The expression levels of ACE, chymase, and Ang II type 1 and type 2 receptor (AT1R and AT2R) mRNAs were determined by in situ hybridization in renal specimens from 18 patients with IgAN, 5 patients with non-IgA mesangial proliferative glomerulonephritis (non-IgAN) and 10 patients with nonmesangial proliferative glomerulonephritis (minimal change nephrotic syndrome, n = 5, and membranous nephropathy, n = 5). Normal portions of surgically resected kidney served as control. Results: In normal kidney, a few mesangial cells and glomerular and tubular epithelial cells weakly expressed ACE, chymase and AT1R mRNAs. In IgAN and non-IgAN samples, ACE, chymase, AT1R and AT2R mRNAs were expressed in resident glomerular cells, including mesangial cells, glomerular epithelial cells and cells of Bowman’s capsule. The glomerular expressions in IgAN were stronger than in minimal change nephrotic syndrome and membranous nephropathy. In IgAN, the expressions in glomeruli correlated with the degree of mesangial hypercellularity, whereas the expression levels were weaker at the area of mesangial expansion. IgAN with severe tubulointerstitial injury showed expression of ACE, chymase, AT1R and AT2R mRNAs in atrophic tubules and infiltrating cells and such expression correlated with the degree of tubulointerstitial damage. Conclusion: Our results suggest that renal cells can produce RAS components and that locally synthesized Ang II may be involved in tissue injury in IgAN through Ang II receptors in the kidney.
Comparison of the Effects of Metoclopramide and Domperidone on HERG Channels
Authors: Claassen Sonja , Zünkler Bernd J.
Published: January 2005

Torsades de pointes (TdP) is a potentially fatal form of ventricular arrhythmia that occurs under conditions where cardiac repolarization is delayed (as indicated by prolonged QT intervals from electrocardiographic recordings). A likely mechanism for QT prolongation and TdP is blockade of the rapid component of the cardiac delayed rectifier K+ current (IKr), which is encoded by HERG (human ether-a-go-go-related gene). The gastroprokinetic agent cisapride is a potent blocker of HERG currents and serious cardiac arrhythmias and deaths from TdP and ventricular fibrillation have been reported in patients taking cisapride. The aim of the present study was to compare the effects of the gastroprokinetic agents domperidone and metoclopramide on HERG channels transiently expressed in human embryonic kidney (HEK 293) cells using the whole-cell configuration of the patch-clamp technique. Both domperidone and metoclopramide concentration-dependently blocked HERG currents, and the following values were calculated for IC50 (the concentrations causing half-maximal inhibition) and n (the Hill coefficient): 57.0 nmol/l and 0.99 for domperidone, 5.4 µmol/l and 0.95 for metoclopramide. The observation that the extent of block of HERG currents by domperidone increased at more positive membrane potentials whereas block of HERG currents by metoclopramide displayed a smaller degree of voltage dependency seems to indicate that domperidone and metoclopramide have distinct binding sites on HERG channels. In conclusion, the potency for block of HERG currents is about 100-fold lower for metoclopramide when compared to domperidone.
Protective Effects of Taurine against Nicotine-Induced Oxidative Damage of Rat Urinary Bladder and Kidney
Authors: Şener Göksel , Şehirli Özer , İpçi Yesim , Çetinel Şule , Çikler Esra , Gedik Nursal , Alican İnci
Published: January 2005

Several studies demonstrate that taurine treatment prevents tissue damage in various models of inflammation. Experiments have shown that chronic nicotine administration caused oxidant damage in various organs by increasing lipid peroxidation products and decreasing the activity of endogenous antioxidants. The aim of this study was to investigate the effects of taurine treatment on nicotine-induced oxidative changes in rat urinary bladder and kidney and to explore the possible mechanisms of action. Male Wistar albino rats were injected with nicotine hydrogen bitartrate (0.6 mg/kg i.p.) or saline for 21 days. Taurine was administered (50 mg/kg i.p.) alone or along with nicotine injections. At the end of the treatment period bladder tissue was used for in vitro contractility studies, or stored along with kidney tissue for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Tissue samples were also examined histologically. Serum samples were stored for the measurement of MDA, GSH, blood urea nitrogen, creatinine and lactate dehydrogenase activity. Chronic nicotine treatment decreased the contractile activity of the bladder strips to carbachol and increased lipid peroxidation, MPO levels and tissue collagen content of the bladder and kidney samples. Taurine supplementation to nicotine-treated animals reversed the contractile dysfunction of the bladder strips. It also preserved the renal functions, restored the endogenous GSH levels and decreased high lipid peroxidation and MPO activities in both urinary bladder and kidney tissues. These data suggest that taurine supplementation effectively counteracts the deleterious effect of chronic nicotine administration on bladder and kidney functions and attenuates oxidative damage possibly by its antioxidant effects.