bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the Inhibition of Renshaw Cells During Subthreshold and Suprathreshold Conditions Using Anatomically and Physiologically Realistic Models
Authors: Bui Tuan V. , Dewey Dianne E. , Fyffe Robert E. W. , Rose P. Ken
Published: May 2005

Inhibitory synaptic inputs to Renshaw cells are concentrated on the soma and the juxtasomatic dendrites. In the present study, we investigated whether this proximal bias leads to more effective inhibition under different neuronal operating conditions. Using compartmental models based on detailed anatomical measurements of intracellularly stained Renshaw cells, we compared the inhibition produced by glycine/γ-aminobutyric acid-A (GABAA) synapses when distributed with a proximal bias to the inhibition produced when the same synapses were distributed uniformly (i.e., with no regional bias). The comparison was conducted in subthreshold and suprathreshold conditions. The latter were mimicked by voltage clamping the soma to −55 mV. The voltage clamp reduces nonlinear interactions between excitatory and inhibitory synapses. We hypothesized that for electrotonically compact cells such as Renshaw cells, the strength of the inhibition would become much less dependent on synaptic location in suprathreshold conditions. This hypothesis was not confirmed. The inhibition produced when inhibitory inputs were proximally distributed was always stronger than when the same inputs were uniformly distributed. In fact, the relative effectiveness of proximally distributed inhibitory inputs over uniformly distributed synapses was greater in suprathreshold conditions than that in subthreshold conditions. The somatic voltage clamp minimized saturation of inhibitory driving potentials. Because this effect was greatest near the soma, the current produced by more distal synapses suffered a greater loss because of saturation. Conversely, in subthreshold conditions, the effectiveness of proximal synapses was substantially reduced at high levels of background synaptic activity because of saturation. Our results suggest glycine/GABAAsynapses on Renshaw cells are strategically distributed to block the powerful excitatory drive produced by recurrent collaterals from motoneurons.
Motion Adaptation Leads to Parsimonious Encoding of Natural Optic Flow by Blowfly Motion Vision System
Authors: Heitwerth J. , Kern R. , van Hateren J. H. , Egelhaaf M.
Published: May 2005

Neurons sensitive to visual motion change their response properties during prolonged motion stimulation. These changes have been interpreted as adaptive and were concluded, for instance, to adjust the sensitivity of the visual motion pathway to velocity changes or to increase the reliability of encoding of motion information. These conclusions are based on experiments with experimenter-designed motion stimuli that differ substantially with respect to their dynamical properties from the optic flow an animal experiences during normal behavior. We analyze for the first time motion adaptation under natural stimulus conditions. The experiments are done on the H1-cell, an identified neuron in the blowfly visual motion pathway that has served in many previous studies as a model system for visual motion computation. We reconstructed optic flow perceived by a blowfly in free flight and used this behaviorally generated optic flow to study motion adaptation. A variety of measures (variability in spike count, response latency, jitter of spike timing) suggests that the coding quality does not improve with prolonged stimulation. However, although the number of spikes decreases considerably during stimulation with natural optic flow, the amount of information that is conveyed stays nearly constant. Thus the information per spike increases, and motion adaptation leads to parsimonious coding without sacrificing the reliability with which behaviorally relevant information is encoded.
Effects of Interlimb and Intralimb Constraints on Bimanual Shoulder–Elbow and Shoulder–Wrist Coordination Patterns
Authors: Li Yong , Levin Oron , Forner-Cordero Arturo , Swinnen Stephan P.
Published: June 2005

The present study addressed the interactions between interlimb and intralimb constraints during the control of bimanual multijoint movements. Participants performed eight coordination tasks involving bilateral shoulder–elbow ( expt I) and shoulder–wrist ( expt II) movements. Three principal findings were obtained. First, the principle of muscle homology (inphase coordination), giving rise to mirror symmetrical movements with respect to the midsagittal plane, had a powerful influence on the quality of interlimb coordination. In both experiments, the accuracy and stability of inter- and/or intralimb coordination deteriorated as soon as the antiphase mode was introduced in one or both joint pairs. However, the mutual influences between bilateral distal and proximal joint pairs varied across coordination tasks and effectors. Second, the impact of intralimb coordination modes on the quality of intralimb coordination was inconsistent between adjacent ( expt I) and nonadjacent joint ( expt II) combinations. Third, the mode of interlimb coordination affected the quality of intralimb coordination, whereas strong support for the converse effect was not obtained. Taken together, these observations point to a hierarchical control structure whereby interlimb coordination constraints have a stronger impact on the global coordination of the system than intralimb constraints, whose impact is substantially dependent on effector and task. The finding that intralimb coordination is subordinate to interlimb coordination during the production of bimanual multijoint coordination patterns indicates that symmetry is a major organizational principle in the neural control of complex movement.
Bimanual Interference in Rapid Discrete Movements Is Task Specific and Occurs at Multiple Levels of Processing
Authors: Obhi Sukhvinder S. , Goodale Melvyn A.
Published: May 2005

It has been suggested that interference in symbolically cued bimanual reaction time tasks is caused primarily by the perceptual processing of stimuli and not by motor preparation of the required movements. Here subjects made movements of the right and left index fingers that varied in their spatial and motor congruence. Spatial congruence was manipulated by presenting symbolic cues (i.e., pairs of letters) on a computer screen cueing the required movement directions. Motor congruence was manipulated by altering hand orientation. Results showed that interference occurs at both the stage of stimulus processing and the stage of motor preparation. These effects were reflected in the latencies of the different bimanual movements with both motor incongruence and spatial incongruence causing significant increases in reaction time. However, spatially incongruent movements that were made in response to incongruent visual cues demonstrated changes in reaction time that were more than double those of movements that required simultaneous activation of nonhomologous muscles. Therefore in symbolically cued bimanual reaction-time tasks, although both motor and spatial constraints operate, there is a clear dominance of spatial incongruence on performance. While motor congruence effects are likely due to cross-facilitation in corticospinal pathways, spatial incongruence effects are probably due to interference between the mechanisms that identify incongruent stimuli and translate these cues into the appropriate movements.
Sensitivity to Voice in Human Prefrontal Cortex
Authors: Fecteau Shirley , Armony Jorge L. , Joanette Yves , Belin Pascal
Published: June 2005

We report two functional MRI (fMRI) experiments showing sensitivity to human voice in a region of human left inferior prefrontal cortex, pars orbitalis. The voice-enhanced response was observed for speech as well as nonlinguistic vocalizations and was stronger for emotional than neutral vocalizations. This region could constitute a human prefrontal auditory domain similar to the one recently identified in the macaque brain.
Time-Dependent Activation of Feed-Forward Inhibition in a Looming-Sensitive Neuron
Authors: Gabbiani Fabrizio , Cohen Ivan , Laurent Gilles
Published: June 2005

The lobula giant movement detector (LGMD) is an identified neuron in the locust visual system that responds preferentially to objects approaching on a collision course with the animal. For such looming stimuli, the LGMD firing rate gradually increases, peaks, and decays toward the end of approach. The LGMD receives both excitatory and feed-forward inhibitory inputs on distinct branches of its dendritic tree, but little is known about the contribution of feed-forward inhibition to its response properties. We used picrotoxin, a chloride channel blocker, to selectively block feed-forward inhibition to the LGMD. We then computed differences in firing rate and membrane potential between control and picrotoxin conditions to study the activation of feed-forward inhibition. For looming stimuli, a significant activation of inhibition was observed early, as objects exceeded on average ∼23° in angular extent at the retina. Inhibition then increased in parallel with excitation over the remainder of approach trials. Experiments in which the final angular size of the approaching objects was systematically varied revealed that the relative activation of excitation and inhibition remains well balanced over most of the course of looming trials. Feed-forward inhibition actively contributed to the termination of the response to approaching objects and was particularly effective for large or slowly moving objects. Suddenly appearing and receding objects activated excitation and feed-forward inhibition nearly simultaneously, in contrast to looming stimuli. Under these conditions, the activation of excitation and feed-forward inhibition was weaker than for approaching objects, suggesting that both are preferentially tuned to approaching objects. These results support a phenomenological model of multiplication within the LGMD and provide new constraints for biophysical models of its responses to looming and receding stimuli.
Reward, Motivation, and Emotion Systems Associated With Early-Stage Intense Romantic Love
Authors: Aron Arthur , Fisher Helen , Mashek Debra J. , Strong Greg , Li Haifang , Brown Lucy L.
Published: June 2005

Early-stage romantic love can induce euphoria, is a cross-cultural phenomenon, and is possibly a developed form of a mammalian drive to pursue preferred mates. It has an important influence on social behaviors that have reproductive and genetic consequences. To determine which reward and motivation systems may be involved, we used functional magnetic resonance imaging and studied 10 women and 7 men who were intensely “in love” from 1 to 17 mo. Participants alternately viewed a photograph of their beloved and a photograph of a familiar individual, interspersed with a distraction-attention task. Group activation specific to the beloved under the two control conditions occurred in dopamine-rich areas associated with mammalian reward and motivation, namely the right ventral tegmental area and the right postero-dorsal body and medial caudate nucleus. Activation in the left ventral tegmental area was correlated with facial attractiveness scores. Activation in the right anteromedial caudate was correlated with questionnaire scores that quantified intensity of romantic passion. In the left insula-putamen-globus pallidus, activation correlated with trait affect intensity. The results suggest that romantic love uses subcortical reward and motivation systems to focus on a specific individual, that limbic cortical regions process individual emotion factors, and that there is localization heterogeneity for reward functions in the human brain.
A genomic approach to reveal novel genes associated with myotube formation in the model teleost,Takifugu rubripes
Authors: Fernandes Jorge M. O. , Mackenzie Matthew G. , Elgar Greg , Suzuki Yuzuru , Watabe Shugo , Kinghorn James R. , Johnston Ian A.
Published: June 2005

Little is known about the transcriptional networks that regulate myotube production in vertebrates. In the present study, we have used a genomic approach to discover novel genes associated with myotube formation in fast muscle of the tiger puffer fish, Takifugu rubripes. The number of fast muscle fibers per myotome increased until 1.2 kg body mass, and subsequent growth was by fiber hypertrophy alone. Forward and reverse subtracted cDNA libraries were prepared from a 180-g (myotube +) and a 3.4-kg (myotube −) fish, and 1,452 expressed sequence tags (ESTs) were obtained. After these ESTs were grouped into nonredundant clusters and housekeeping and structural genes were eliminated, 57 genes were selected and quantitative PCR was used to investigate their expression levels in different tissues from independent groups of myotube(−) and myotube(+) fish acclimated to the same environmental conditions and diet. Eleven novel genes were found to be consistently differentially expressed, but only four showed appropriate tissue-specific expression. These four genes were upregulated 5–25 times in fast muscle of myotube(−) relative to myotube(+) growth stages, while their expression remained unchanged in the other tissues studied. The novel genes identified, which are also present in other vertebrate genomes, may play a role in inhibiting myotube formation in vertebrate muscle.
Modeling of Fenton Reaction for the Oxidation of Phenol in Water
Authors: Chedeville Olivier , Tosun-Bayraktar Ayse , Porte Catherine
Published: June 2005

Phenol is an organic pollutant found in various types of industrial wastewater. Due to its bactericidal properties, it is difficult to eliminate it by classic treatment methods. In this work, the degradation of this compound by Fenton reaction at mild temperature and pressure conditions is studied. An experimental design was applied in order to quantify the influence of operating parameters on the efficiency of this method. The field of study was defined between 20 and 50 °C for the temperature, 1 and 4 g L −1 for the phenol concentration, 10 and 28 for the H2O2 to phenol molar ratio, and 0.02 to 0.08 for the Fe(II) to phenol concentration ratio. It was shown that the temperature and the amount of catalyst have a strong influence. A model giving the decrease of COD was established. The COD decrease was between 40% and 72% and phenol had totally disappeared.
The Nasal Airflow in Noses with Septal Perforation: A Model Study
Authors: Grützenmacher S. , Mlynski R. , Lang C. , Scholz S. , Saadi R. , Mlynski G.
Published: June 2005

Background: Septal perforation is a common clinical problem in rhinology. Affected patients suffer from a dry nose, crusts as well as recurrent epistaxis and sometimes an inspiratory whistle. The aim of this study was to investigate the underlying flow dynamic mechanisms. Methods: The physical flow effects of such pathologies were examined in functional nose models (box models) and anatomically exact models of the nose. Therefore, septal perforations of different sizes and localisations were studied in straight and deviated nasal septa. Results and Conclusions: It could be seen that the localisation of the perforation has no impact on the flow pattern. In large septal perforations, the air jet collides with the posterior edge of the perforation and disintegrates turbulently. Since airflow is physiologically turbulent in the posterior part of the nose, posterior perforations do not cause clinical complaints. The inspiratory whistling sound during respiration is based on the principle of a lip whistle. Large perforations do not cause a whistling sound. The necessary high flow velocity needed in large perforations is usually not achievable.
Effects of Silica on Mitochondrial Functions of the Proximal Tubule Cells in Rats
Authors: Öner G. , Cirrik S. , Bakan O.
Published: June 2005

Aim: Despite the belief that silica (Si) is an inert and non-toxic ingredient, latest studies indicated that it is a potent mitochondria activator and Si-induced ROS generation is involved in the inflammatory reactions of silicotic lungs. Si cytotoxicity has been well studied in phagocytic cells, but its effects on the mitochondria of proximal tubule cells which are continuously exposed to filtered blood-borne soluble Si were not known. Methods: Using renal cortical slices and isolated mitochondria, the effect of high dietary Si on the mitochondrial functions of proximal tubule cells was studied in rats exposed to 50 mg/kg sodium metasilicate-containing water for 8 days. Results: Digested Si did not accumulate in kidney cortex, it was totally eliminated in the urine. Glomerular filtration rate as well as urine output were normal. Despite unaltered blood and cortex Si levels, ammonia production of cortical slices and isolated mitochondria was increased significantly and this was further increased by L-NAME pre-treatment. Elevated mitochondrial oxygen utilization was associated with increased ammonia production. Cyclosporin-A-sensitive mtPTP increase was associated with unchanged KATP channels in the mitochondria of Si-exposed rats. Conclusion: These results suggested that dietary Si increases both extracellular and intracellular ammoniagenesis by elevating mitochondrial oxygen utilisation.
Role of Leukotriene Inhibitors in the Postoperative Management of Nasal Polyps
Authors: Mostafa Badr E. , Hay Hossam Abdel , Mohammed Hussam E. , Yamani Mohammed
Published: June 2005

This was a prospective double blind comparative study on 40 patients. It compared the effects of the leukotriene receptor antagonist montelukast and beclomethasone nasal spray on the post-operative course of patients with sinonasal polyps. All patients underwent endoscopic sphenoethmoidectomy and were randomized post-operatively into two groups. Group I: 20 patients (9 females and 11 males) age 17 to 67 (32.4 ± 9.5 years), receiving 10 mg montelukast orally daily and Group II: 20 patients (6 females and 14 males) age 17 years to 57 years (33.5 ± 11.9 years), receiving 400 ug beclomethasone local sprays daily. All patients were followed up for 1 year and a symptom score was recorded throughout this period. There was a significant reduction in symptom scores in both groups throughout the study period. In the montelukast group improvement was more marked in itching, post-nasal discharge and headache. The control of sneezing and rhinorrhea was comparable in both groups with a marginal advantage of montelukast. Steroids had a more marked effect on smell disturbances and obstruction. There was no difference in the recurrence rate or in the need for rescue medications between both groups. Both drugs seem to have a complementary action and further studies are needed to determine which patients should receive which treatment.
The Efficacy of Intravitreal Piperacillin/Tazobactam in Rabbits with Experimental Staphylococcus epidermidis Endophthalmitis: A Comparison with Vancomycin
Authors: Özkiriş Abdullah , Evereklioglu Cem , Eşel Duygu , Akgün Hülya , Erkiliç Kuddusi
Published: June 2005

Background: To investigate the efficacy of intravitreal piperacillin/tazobactam in rabbit eyes with experimental S. epidermidis endophthalmitis and to compare the outcomes with intravitreal vancomycin application. Material and Methods: Twenty-four New Zealand white albino rabbits were divided into three equal groups (n = 8 in each), and the right eyes received 0.1-ml intravitreal injections of S. epidermidis suspension. The left eyes served as uninfected controls and were injected with 0.1 ml of saline solution. The right eyes of rabbits in group 1 were treated with intravitreal injection of 250 µg/0.1 ml piperacillin/tazobactam 24 h after intravitreal inoculation of S. epidermidis whereas group 2 eyes received intravitreal 1 mg/0.1 ml vancomycin. Group 3 eyes received no treatment and served as infected controls. Clinical examination of the eyes in each group was performed on the 1st, 3rd and 6th day after the inoculation of S. epidermidis. On the 6th day, 0.1-ml vitreous aspirates were obtained for microbiological analysis, and then the eyes were enucleated for histopathological evaluation. Results: There were no statistically significant differences in mean clinical scores between the groups on the first day after S. epidermidis inoculation (p > 0.05). On the 6th day, the mean clinical score of group 3 was significantly higher (p < 0.001), but the mean clinical scores of groups 1 and 2 were similar (p = 0.812). The mean logarithmic value of colony-forming units per milliliter of groups 1, 2 and 3 were 0.6 ± 1.3, 0.5 ± 1.5 and 5.3 ± 0.7, respectively. Mean histopathological scores of the groups were 8.3 ± 0.9, 7.5 ± 1.3 and 15.6 ± 1.2, respectively. Group 3 eyes had significantly more colony-forming units per milliliter and a higher histopathological score (for each, p < 0.001), and there were no statistically significant differences in microbiological and histopathological scores between groups 1 and 2 (for each, p > 0.05). Conclusion: Intravitreal application of 250 µg/0.1 ml piperacillin/tazobactam seems to be approximately equally effective with intravitreal 1 mg/0.1 vancomycin application in the treatment of experimental S. epidermidis endophthalmitis. Therefore, intravitreal piperacillin/tazobactam may be an alternative therapeutic option in the treatment of S. epidermidis endophthalmitis.
Postural Control in Patients with Unilateral Vestibular Lesions Is More Impaired in the Roll than in the Pitch Plane: A Static and Dynamic Posturography Study
Authors: Mbongo F. , Patko T. , Vidal P.P. , Vibert N. , Tran Ba Huy P. , de Waele C.
Published: June 2005

The postural instability of patients with vestibular loss (11 with bilateral and 101 with unilateral vestibular loss) at different times following the lesion was investigated by means of posturography and compared to healthy subjects. In addition, subjects submitted to galvanic vestibular stimulation were also studied to compare their postural performances with those of patients with complete unilateral vestibular lesion. The platform consisted of a static computerized force platform, on which a seesaw platform could be placed to test the subjects in dynamic conditions. The displacement of the center of foot pressure was measured under different conditions: subjects standing on the fixed platform, eyes open and eyes closed and subjects standing on the seesaw platform, eyes open and eyes closed. In the last condition, balance was tested in the subject’s pitch plane by allowing the platform to rotate forwards and backwards only and in the patient’s roll plane by allowing the platform to rotate to the left and to the right. The results showed that in static conditions, only bilateral vestibular loss patients had abnormal values compared to controls. In contrast, in dynamic eyes-closed conditions, both bilateral and unilateral patients could be differentiated from controls. Bilateral patients were unable to stand up without falling in both pitch and roll planes. Unilateral patients fell in the first week following the lesion and exhibited increased postural oscillations in both planes from the 2-week up to the 1-year postlesion stage. In addition and more importantly, they fell more often or had higher sway in the roll than in the pitch plane. Therefore, this study suggests that dynamic posturography on a seesaw platform could be a valuable tool for clinical diagnosis and quantitative analysis of imbalance in patients suffering from a unilateral vestibular loss up to 1 year after the lesion.
Intra-Arterial Thrombus Visualized on T2* Gradient Echo Imaging in Acute Ischemic Stroke
Authors: Assouline E. , Benziane K. , Reizine D. , Guichard J.P. , Pico F. , Merland J.J. , Bousser M.G. , Chabriat H.
Published: June 2005

Background: MR signal loss related to arterial thrombosis leading to vascular susceptibility artifacts (VSA) has recently been reported on gradient echo images. The time course and sensitivity of VSA in acute stroke patients has been scarcely investigated. The aim of this study was to assess the frequency and course of VSA in acute stroke patients, to compare its sensitivity to distinct features of arterial occlusion as detected on FLAIR images or on CT scan. Methods: Twenty-nine patients were scanned from 45 min to 6 h after stroke onset using identical MR parameters. All had an acute ischemic lesion identified on diffusion-weighted images, 25 had an occlusion of MCA or PCA confirmed by magnetic resonance angiography. Results: VSA was detected in 22/25 patients having an occluded artery at the time of MRI examination. Flair disclosed a hyperintense vessel in all of these 25 cases, but CT scan revealed a hyperdense artery in only 15 cases. Follow-up studies showed that VSA can vanish or disappear after partial recanalization. When the artery remains occluded, VSA can decrease, disappear or increase in the next hours, possibly related to structural modifications of the thrombus with time. Most occlusions were due to cardiac and arterial emboli or to intracranial extension of carotid occlusion. Conclusions: VSA are frequent in the first hours of MCA or PCA occlusion in acute stroke patients. The sensitivity of VSA appears lower than the arterial hyperintensity on FLAIR images but higher than the hyperdense artery sign on CT scan. The extent and intensity of VSA can change with recanalization or structural modifications of the thrombus.
Results of a Multicentre, Randomised Controlled Trial of Intra-Arterial Urokinase in the Treatment of Acute Posterior Circulation Ischaemic Stroke
Authors: Macleod M.R. , Davis S.M. , Mitchell P.J. , Gerraty R.P. , Fitt G. , Hankey G.J. , Stewart-Wynne E.G. , Rosen D. , McNeil J.J. , Bladin C.F. , Chambers B.R. , Herkes G.K. , Young D. , Donnan G.A.
Published: June 2005

Background: Patients with ischaemic stroke due to occlusion of the basilar or vertebral arteries may develop a rapid deterioration in neurological status leading to coma and often to death. While intra-arterial thrombolysis may be used in this context, no randomised controlled data exist to support its safety or efficacy. Methods: Randomised controlled trial of intra-arterial urokinase within 24 h of symptom onset in patients with stroke and angiographic evidence of posterior circulation vascular occlusion. Results: Sixteen patients were randomised, and there was some imbalance between groups, with more severe strokes occurring in the treatment arm. A good outcome was observed in 4 of 8 patients who received intra-arterial urokinase compared with 1 of 8 patients in the control group. Conclusions: These results support the need for a large-scale study to establish the efficacy of intra-arterial thrombolysis for acute basilar artery occlusion.
Ultrasound-Induced Blood Clot Dissolution without a Thrombolytic Drug Is More Effective with Lower Frequencies
Authors: Nedelmann Max , Brandt Christian , Schneider Felicitas , Eicke B. Martin , Kempski Oliver , Krummenauer Frank , Dieterich Marianne
Published: June 2005

Background and Purpose: Therapeutic ultrasound as stand-alone therapy or in combination with rt-PA has proven to be an effective measure for recanalisation of acute vessel occlusion in different in vitro and in vivo studies. Uncertainty still exists concerning the optimal frequency and intensity with regard to the thrombolytic efficacy of ultrasound. The purpose of this study was a direct comparison of different ultrasound frequencies, when otherwise using identical measurement settings and parameters. Methods: Ultrasound-induced dissolution of fresh human blood clots was studied in a flow system using low-frequency continuous wave ultrasound of 20, 40 and 60 kHz. After calibration of each ultrasound probe, blood clots were exposed to local time average intensities of either 0.12 or 0.2 W/cm2. Exposure time of the clots to ultrasound was 10 min, the number of treated clots in each experimental group was 12. Results: As tested with 0.2 W/cm2, we found the most pronounced thrombolytic effect with the 20-kHz probe (weight loss of blood clots: 52.4%) and the 40-kHz probe (49.4%), as compared to the 60-kHz probe (21.4%) and the control group (18.5%). The difference between the 20- and 60-kHz probes was statistically significant (p < 0.001). The treatment effect was clearly intensity dependent with a less pronounced, but still significant treatment effect at 0.12 W/cm2 (24.5% at 20 kHz; p < 0.001 compared to 0.2 W/cm2; p = 0.045 compared to controls). Conclusions: These data show that therapeutic efficacy of ultrasound, in absence of a thrombolytic drug, is frequency and intensity dependent with best results at low frequencies. With continuous wave transmission, the benefit may be limited to the very low frequency range. The results are a basis for further evaluation in animal models.
Characterization of the Integrin αvβ3 in Arteriovenous Malformations and Cavernous Malformations
Authors: Lim Michael , Haddix Terri , Harsh Griffith R. , Vogel Hannes , Steinberg Gary K. , Guccione Samira
Published: June 2005

Background: Alpha V beta 3 (αvβ3) is an integrin specifically expressed on the endothelial cells of central nervous system (CNS) neoplasms. However, no data exist on the expression of αvβ3 in vascular malformations of the CNS. In this study, we investigate the expression of αvβ3 in arteriovenous malformations (AVMs) and cavernous malformations (CMs). Method: Frozen samples of AVMs from 12 patients and CMs from 5 patients were obtained intraoperatively. Once the final pathology had been confirmed, immunohistochemistry was performed using an antibody to the integrin αvβ3. The αvβ3 expression pattern was graded according to the percentage of positively staining vessels. Results: Ten of 12 AVMs demonstrated αvβ3 immunopositivity. Six of these 10 AVMs had moderate or strong staining. Most notably, 5 of the 6 moderate or strongly staining AVMs came from patients 22 years of age or younger. Four of these 6 AVMs had previously been embolized. None of the cavernous malformations demonstrated αvβ3 immunopositivity. Discussion: αvβ3 may contribute to the formation of AVMs in younger patients. αvβ3 may also provide a potential therapeutic target. The lack of αvβ3 expression in cavernous malformations, despite their high vascular densities, suggests that the pathophysiology of their formation differs from that of AVMs.
Detection of Chromosome Abnormalities by Quantitative Fluorescent PCR in Ectopic Pregnancies
Authors: Goddijn Mariette , van Stralen Marja , Schuring-Blom Heleen , Redeker Bert , van Leeuwen Liesbeth , Repping Sjoerd , Leschot Nico , van der Veen Fulco
Published: June 2005

Objective: To evaluate the potential value of quantitative fluorescent polymerase chain reaction (QF-PCR) in the detection of chromosome abnormalities in ectopic pregnancies. Methods: Seventy chorionic villi samples of ectopic pregnancies were studied by QF-PCR. Primers for chromosomes 16, 21, X and Y in chorionic villi were evaluated. Fluorescence in situ hybridization (FISH) was performed when results of QF-PCR showed aneuploidy, in case of unexplicable QF-PCR peaks, and in 10 cases with normal QF-PCR results. Results: QF-PCR produced a result for chromosomes X and Y in 66 cases (94%), for chromosome 16 in 62 cases (89%) and for chromosome 21 in 55 cases (79%). Overall, QF-PCR produced a result for the chromosomes tested in 54 ectopic pregnancy cases (77%). Fifty-two of these results were normal disomic (96%) and two were abnormal, one trisomy 16 (2%) and one triploidy (2%). In 16 cases (23%) no definite QF-PCR results could be obtained for all chromosomes, 11 due to amplification failure, and 5 due to unexplicable QF-PCR peaks. In 10 cases with normal QF-PCR results, disomy was confirmed by FISH. The trisomy 16 was also confirmed by FISH. Furthermore, a result was obtained with FISH in 5 of the cases without definite QF-PCR results. Conclusion:Although QF-PCR can establish the chromosomal status in ectopic pregnancies for chromosomes 16, 21, X and Y in the majority of cases, the technical failure rate is still considerable and does not improve results when compared to cytogenetic techniques.
A Case of Cronkhite-Canada Syndrome with Taste Disturbance as a Leading Complaint
Authors: Blonski Wojciech C. , Furth Emma E. , Kinosian Bruce P. , Compher Charlene , Metz David C.
Published: June 2005

Cronkhite-Canada syndrome was first described in 1955. The clinical features of this rare syndrome of unknown etiology include nonhereditary gastrointestinal polyposis together with diarrhea, nail dystrophy, alopecia, and hyperpigmentation of the skin. This syndrome has been divided into five clinical types based on initial symptoms. We describe a case of Cronkhite-Canada syndrome presenting with taste disturbance as the major symptom, present a comprehensive review of the literature concerning this rare syndrome, and suggest therapeutic treatment options.
Effect of an Oat Bran-Rich Supplement on the Metabolic Profile of Overweight Premenopausal Women
Authors: Robitaille Julie , Fontaine-Bisson Bénédicte , Couture Patrick , Tchernof André , Vohl Marie-Claude
Published: June 2005

Background/Aims: A healthy diet is a key factor in the prevention of cardiovascular disease, the leading cause of death for women in industrialized countries. In this regard, soluble fibers may have beneficial effects on the plasma lipoprotein/lipid profile. The objective of the present study was to investigate the plasma lipoprotein/lipid response to dietary fibers in overweight premenopausal women within a randomized controlled trial. Methods: Following a 2-week run-in phase, 34 premenopausal women (age: 22–53 years) were randomly assigned either to the control group (no supplement) or to the treatment group, which received 2 oat bran-enriched muffins per day (28 g/day of oat bran) during 4 weeks. Results: Supplementation with oat bran had a beneficial effect on plasma HDL-C levels. Indeed, compared to the control group (n = 16), a mean increase in plasma HDL-C levels of 11.2% was observed in women eating the oat bran supplement (n = 18) (p = 0.01), whereas the total cholesterol/HDL-C ratio decreased by 7.0% (p = 0.002). Results were similar after adjustment for age, apo E genotype and weight change. Conclusion: These results suggest that oat bran-rich foods have beneficial effect on the metabolic profile of overweight women. Integration of these foods as part of a healthy diet may, therefore, improve the cardiovascular risk profile of women.
Herpetic Lumbosacral Radiculoneuropathy in Patients with Human Immunodeficiency Virus Infection
Authors: Yoritaka Asako , Ohta Keiko , Kishida Shuji
Published: June 2005

We report 4 cases of human immunodeficiency virus infection associated with lumbosacral radicular dysfunction and urinary retention. Three of these cases had the so-called Elsberg syndrome in that their symptoms were associated with genital herpes. In 1 case, different herpes simplex virus types were isolated from the cerebrospinal fluid and genital swabs. Lumbosacral radiculoneuropathy with urinary retention caused by herpes viruses can develop not only with an initial genital herpes infection, but also due to reactivation of a latent herpes virus.
Low Extracellular Cl– Environment Attenuates Changes in Intracellular pH and Contraction following Extracellular Acidosis in Wistar Kyoto Rat Aorta
Authors: Rohra Dileep Kumar , Saito Shin-ya , Ohizumi Yasushi
Published: June 2005

This study was conducted to investigate the influence of extracellular Cl– ([Cl–]o) on the intracellular pH (pHi) regulation and the contractile state of the isolated aorta from Wistar Kyoto (WKY) rats. Isometric tension recording and fluorometry techniques were utilized to measure contractile response and pHi in isolated aortic strips. Decreasing extracellular pH (pHo) from 7.4 to 6.5 produced a marked contraction, which was 75.8 ± 5.6% of the 64.8 mmol/l KCl-induced contraction. The acidosis-induced contraction was significantly attenuated in low [Cl–]o solution, the magnitude of which was 56.0 ± 3.0% of the 64.8 mmol/l KCl-induced contraction. Decreasing pHo of the normal solution to 6.5 rapidly decreased pHi in aortic smooth muscle cells and produced a corresponding contraction. When the pHo was decreased in low [Cl–]o solution, a rapid fall in pHi followed by reversal of pHi changes, in a time-dependent manner was observed, despite low pHo. Omission of HCO3– from the low [Cl–]o solution restored the contractile response to acidosis, which was comparable to that in normal solution. Similarly, following decrease in pHo to 6.5, no recovery of intracellular acidosis was observed. We conclude that low [Cl–]o environment causes activation of extracellular HCO3–-dependent pHi-regulating mechanism, that results in the rapid recovery of pHi following acidosis, and the attenuation of acidosis-induced contraction of WKY aorta.
Role of Endothelin in Mediating Tumor Necrosis Factor-Induced Hypertension in Pregnant Rats
Authors: LaMarca B. Babbette D. , Cockrell Kathy , Sullivan Elizabeth , Bennett William , Granger Joey P.
Published: June 2005

Hypertension during preeclampsia is associated with an increase in plasma levels of tumor necrosis factor (TNF)-α, a cytokine known to contribute to endothelial dysfunction. Recently, our laboratory reported that a 2-fold increase in plasma TNF-α produces hypertension in pregnant rats. Endothelin is also elevated in preeclampsia and endothelin synthesis is enhanced by TNF-α. The purpose of this study was to determine the role of endothlelin in mediating TNF-α–induced hypertension in pregnant rats. To achieve this goal, TNF-α (50 ng/d for 5 days) was infused into control pregnant rats and pregnant rats treated with an endothelin receptor A antagonist, ABT 627 (5 mg/kg per day for 5 days). At day 19 of gestation, arterial pressure was measured and aorta, kidneys, and placentas were harvested. Infusion of TNF-α into pregnant rats increased plasma concentration of TNF-α (13.5±0.8 to 28.0±3.7 pg/mL) and arterial pressure (101±2 to 122±1 mm Hg). The increase in arterial pressure was associated with an increase in preproendothelin mRNA expression in placenta, aorta, and kidneys measured by real-time polymerase chain reaction (PCR). Pretreatment with the endothelin receptor A antagonist completely abolished the blood pressure response to TNF-α in pregnant rats (105±1 versus 97±2 mm Hg). In sharp contrast, the ET
A
receptor antagonist had no effect on arterial pressure in normal pregnant rats (97±2 versus 101±2 mm Hg). Moreover, chronic infusion of TNF-α had no significant effect on arterial pressure or renal preproendothelin levels in virgin rats. These results suggest an important role for endothelin in mediating TNF-α–induced hypertension in pregnant rats.
New Definition of Microalbuminuria in Hypertensive Subjects
Authors: Klausen Klaus Peder , Scharling Henrik , Jensen Gorm , Jensen Jan Skov
Published: June 2005

Microalbuminuria has so far been defined as urinary albumin excretion between 20 and 200 μg/min (or 15 to 150 μg/min overnight). In a recent report, an overnight urinary albumin excretion >5 μg/min was strongly predictive of coronary heart disease and death in the general population. The aim of the present study was to confirm this observation in a population of hypertensive individuals. In The Third Copenhagen City Heart Study in 1992 to 1994, 1734 men and women aged 30 to 70 years with hypertension, but no history of coronary heat disease, delivered a timed overnight urine sample. They were followed-up prospectively by registers until 2000 with respect to coronary heart disease, and until 2004 with respect to death. During follow-up, 123 incident cases of coronary heart disease and 308 deaths were traced. Incident coronary heart disease occurred in 11% of subjects with urinary albumin excretion ≥5 μg/min compared with 5% in subjects with urinary albumin excretion <5 μg/min (
P
<0.001). Similarly, the cumulative mortality was 28% versus 13% (
P
<0.001). The relative risks of coronary heart disease and death associated with urinary albumin excretion ≥5 μg/min were 2.0 (1.4 to 2.9;
P
<0.001) and 1.9 (1.5 to 2.3;
P
<0.001), respectively, after adjustment for age, sex, blood pressure level, antihypertensive drugs, diabetes, creatinine clearance, smoking, lipoproteins, and body mass index. In conclusion, our study supports the new definition of microalbuminuria as urinary albumin excretion >5 μg/min. In future risk assessment in hypertensive individuals, measurement of microalbuminuria has to be included.
Adipocyte Signaling and Lipid Homeostasis
Authors: Yu Yi-Hao , Ginsberg Henry N.
Published: May 2005

For many years adipose tissue was viewed as the site where excess energy was stored, in the form of triglycerides (TGs), and where that energy, when needed elsewhere in the body, was released in the form of fatty acids (FAs). Recently, it has become clear that when the regulation of the storage and release of energy by adipose tissue is impaired, plasma FA levels become elevated and excessive metabolism of FA, including storage of TGs, occurs in nonadipose tissues. Most recently, work by several laboratories has made it clear that in addition to FA, adipose tissue communicates with the rest of the body by synthesizing and releasing a host of secreted molecules, collectively designated as adipokines. Several recent reviews have described how these molecules, along with FA, significantly effect total body glucose metabolism and insulin sensitivity. Relatively little attention has been paid to the effects of adipokines on lipid metabolism. In this review, we will describe, in detail, the effects of molecules secreted by adipose tissue, including FA, leptin, adiponectin, resistin, TNF-α, IL-6, and apolipoproteins, on lipid homeostasis in several nonadipose tissues, including liver, skeletal muscle, and pancreatic β cells.
Inflammation of Atrium After Cardiac Surgery Is Associated With Inhomogeneity of Atrial Conduction and Atrial Fibrillation
Authors: Ishii Yosuke , Schuessler Richard B. , Gaynor Sydney L. , Yamada Kiyomi , Fu Annabel S. , Boineau John P. , Damiano Ralph J.
Published: June 2005

Background—

Atrial fibrillation (AF) is common after cardiac surgery. Abnormal conduction is an important substrate for AF. We hypothesized that atrial inflammation alters atrial conduction properties.

Methods and Results—

Normal mongrel canines (n=24) were divided into 4 groups consisting of anesthesia alone (control group); pericardiotomy (pericardiotomy group); lateral right atriotomy (atriotomy group); and lateral right atriotomy with antiinflammatory therapy (methylprednisolone 2 mg/kg per day) (antiinflammatory group). Right atrial activation was examined 3 days after surgery. Inhomogeneity of conduction was quantified by the variation of maximum local activation phase difference. To initiate AF, burst pacing was performed. Myeloperoxidase activity and neutrophil cell infiltration in the atrial myocardium were measured to quantify the degree of inflammation. The inhomogeneity of atrial conduction of the atriotomy and pericardiotomy groups was higher than that of the control group (2.02±0.10, 1.51±0.03 versus 0.96±0.08, respectively;
P
<0.005). Antiinflammatory therapy decreased the inhomogeneity of atrial conduction after atriotomy (1.16±0.10;
P
<0.001). AF duration was longer in the atriotomy and pericardiotomy groups than in the control and antiinflammatory groups (
P
=0.012). There also were significant differences in myeloperoxidase activity between the atriotomy and pericardiotomy groups and the control group (0.72±0.09, 0.41±0.08 versus 0.18±0.03 ΔOD/min per milligram protein, respectively;
P
<0.001). Myeloperoxidase activity of the antiinflammatory group was lower than that of the atriotomy group (0.17±0.02;
P
<0.001). Inhomogeneity of conduction correlated with myeloperoxidase activity (
r
=0.851,
P
<0.001).

Conclusions—

The degree of atrial inflammation was associated with a proportional increase in the inhomogeneity of atrial conduction and AF duration. This may be a factor in the pathogenesis of early postoperative AF. Antiinflammatory therapy has the potential to decrease the incidence of AF after cardiac surgery.
Development of Occlusive Neointimal Lesions in Distal Pulmonary Arteries of Endothelin B Receptor–Deficient Rats
Authors: Ivy D. Dunbar , McMurtry Ivan F. , Colvin Kelley , Imamura Masatoshi , Oka Masahiko , Lee Dong-Seok , Gebb Sarah , Jones Peter Lloyd
Published: June 2005

Background—

Human pulmonary arterial hypertension (PAH) is characterized by proliferation of vascular smooth muscle and, in its more severe form, by the development of occlusive neointimal lesions. However, few animal models of pulmonary neointimal proliferation exist, thereby limiting a complete understanding of the pathobiology of PAH. Recent studies of the endothelin (ET) system demonstrate that deficiency of the ET
B
receptor predisposes adult rats to acute and chronic hypoxic PAH, yet these animals fail to develop neointimal lesions. Herein, we determined and thereafter showed that exposure of ET
B
receptor–deficient rats to the endothelial toxin monocrotaline (MCT) leads to the development of neointimal lesions that share hallmarks of human PAH.

Methods and Results—

The pulmonary hemodynamic and morphometric effects of 60 mg/kg MCT in control (MCT
+/+
) and ET
B
receptor–deficient (MCT
sl/sl
) rats at 6 weeks of age were assessed. MCT
sl/sl
rats developed more severe PAH, characterized by elevated pulmonary artery pressure, diminished cardiac output, and right ventricular hypertrophy. In MCT
sl/sl
rats, morphometric evaluation revealed the presence of neointimal lesions within small distal pulmonary arteries, increased medial wall thickness, and decreased arterial-to-alveolar ratio. In keeping with this, barium angiography revealed diminished distal pulmonary vasculature of MCT
sl/sl
rat lungs. Cells within neointimal lesions expressed smooth muscle and endothelial cell markers. Moreover, cells within neointimal lesions exhibited increased levels of proliferation and were located in a tissue microenvironment enriched with vascular endothelial growth factor, tenascin-C, and activated matrix metalloproteinase-9, factors already implicated in human PAH. Finally, assessment of steady state mRNA showed that whereas expression of ET
B
receptors was decreased in MCT
sl/sl
rat lungs, ET
A
receptor expression increased.

Conclusions—

Deficiency of the ET
B
receptor markedly accelerates the progression of PAH in rats treated with MCT and enhances the appearance of cellular and molecular markers associated with the pathobiology of PAH. Collectively, these results suggest an overall antiproliferative effect of the ET
B
receptor in pulmonary vascular homeostasis.