bluuebunny/crossref_metadata_2025 huggingface dataset:
The Tale is in the Tail: An Alternative Hypothesis for Psychophysical Performance Variability in Dyslexia
Authors: Roach Neil W , Edwards Veronica T , Hogben John H
Published: August 2004

Dyslexic groups have been reported to display poorer mean performance than groups of normal readers on a variety of psychophysical tasks. However, inspection of the distribution of individual scores for each group typically reveals that the majority of dyslexic observers actually perform within the normal range. Differences between group means often reflect the influence of a small number of dyslexic individuals who perform very poorly. While such findings are typically interpreted as evidence for specific perceptual deficiencies in dyslexia, caution in this approach is necessary. In this study we examined how general difficulties with task completion might manifest themselves in group psychophysical studies. Simulations of the effect of errant or inattentive trials on performance produced patterns of variability similar to those seen in dyslexic groups. Additionally, predicted relationships between the relative variability in dyslexic and control groups, and the magnitude of group differences bore close resemblance to the outcomes of a meta-analysis of empirical studies. These results suggest that general, nonsensory difficulties may underlie the poor performance of dyslexic groups on many psychophysical tasks. Implications and recommendations for future research are discussed.
Perceiving Surfaces in Depth beyond the Fusion Limit of Their Elements
Authors: Lee Hwan S , Dobbins Allan C
Published: August 2004

An isolated dot appears double outside a small disparity range called Panum's fusional area. In random-dot stereograms (RDSs), however, this doubling, or diplopia of dot elements is not evident at any disparity. Nevertheless, depth is perceived up to disparities that greatly exceed Panum's fusional limit. Either one is unaware of dot diplopia at disparities exceeding Panum's fusional limit or the fusion limit is extended. To examine these possibilities, we developed a novel RDS in which dichoptically color-coded dots have a distinctive color when fused, and return to their intrinsic colors when diplopic. We measured the fusion limit of dots in this RDS, and compared it to the patent stereopsis limit of the perceived surface in similar RDSs. We found that the fusional area of dots in the RDS was comparable to Panum's fusional area. Furthermore, there was clear dissociation between the fusion limit and the patent stereopsis limit in the RDS. We conclude that the elements composing a surface are not necessarily fused when a large disparity surface is perceived in depth.
Stereoscopic Matching and the Aperture Problem
Authors: van Dam Loes C J , van Ee Raymond
Published: August 2004

In order to perceive stereoscopic depth, the visual system must define binocular disparities. Consider an oblique line seen through an aperture formed by flanking occluders. Because the line is perceived behind the aperture, the line must have disparity relative to the aperture. What is the assigned disparity of the line in this aperture problem? To answer this question five observers adjusted the horizontal disparity of a probe until it was perceived at the same depth as the disparate line behind the aperture. The results show that, when both the horizontal and the vertical disparities of the occluders are well-defined, the probe must have the same horizontal disparity as the horizontal separation between the line half-images. However, when the horizontal and vertical disparities of the occluders are ill-defined, the intersections of the line and the occluder borders can determine the matching direction. In the latter case, the matching direction varies with the aperture orientation and there is considerable variability across observers.
Impact of secondary salinisation on freshwater ecosystems: effects of contrasting, experimental, short-term releases of saline wastewater on macroinvertebrates in a lowland stream
Authors: Marshall Nadine A. , Bailey Paul C. E.
Published: August 2004

In Australia, secondary salinisation of land and water resources is a serious environmental problem. We conducted two field experiments to examine the effects on macroinvertebrates of increased salt concentration (approximately 1000 and 2000 mg L–1 total dissolved solids (TDS)) and mode of salt water release (continuous press release approximately 1500 mg L–1 and four, separate pulses of approximately 3400 mg L–1 TDS). The abundance of the gastropod Ferrissia tasmanica, the mayfly Baetis sp. 5 and scraper and predator functional feeding groups were significantly reduced at 1500 mg L–1, with the effect exacerbated in pulse release channels. Moreover, the pooled abundance of Oligochaeta, Copepoda and Acarina was significantly reduced at 2000 mg L–1 and the number of drifting animals in the pulse treatment channels significantly increased following commencement of salt water release during daylight hours. In contrast, the abundance of 49 other macroinvertebrate taxa, collector–gatherer functional group and species diversity were unaffected by salinity or release schedule. We conclude that much of the existing macroinvertebrate fauna appears to be halotolerant. However, the abundance of halosensitive species will be reduced at 1500 mg L–1. Delivering short pulses of high salt concentration is more detrimental than delivering the same salt load at a low concentration over a longer period of time.
Lack of phylogeography in European mammals before the last glaciation
Authors: Hofreiter Michael , Serre David , Rohland Nadin , Rabeder Gernot , Nagel Doris , Conard Nicholas , Münzel Susanne , Pääbo Svante
Published: August 2004

In many extant animal and plant species in Europe and North America a correlation exists between the geographical location of individuals and the genetic relatedness of the mitochondrial (mt) DNA sequences that they carry. Here, we analyze mtDNA sequences from cave bears, brown bears, cave hyenas, and Neandertals in Europe before the last glacial maximum and fail to detect any phylogeographic patterns similar to those observed in extant species. We suggest that at the beginning of the last glacial maximum, little phylogeographic patterns existed in European mammals over most of their geographical ranges and that current phylogeographic patterns are transient relics of the last glaciation. Cycles of retreat of species in refugia during glacial periods followed by incomplete dispersal from one refugium into other refugia during interglacial periods is likely to be responsible for the deep genetic divergences between phylogeographic clusters of mtDNA seen today.
tRNA dynamics on the ribosome during translation
Authors: Blanchard Scott C. , Kim Harold D. , Gonzalez Ruben L. , Puglisi Joseph D. , Chu Steven
Published: August 2004

Using single-molecule fluorescence spectroscopy, time-resolved conformational changes between fluorescently labeled tRNA have been characterized within surface-immobilized ribosomes proceeding through a complete cycle of translation elongation. Fluorescence resonance energy transfer was used to observe aminoacyl-tRNA (aa-tRNA) stably accommodating into the aminoacyl site (A site) of the ribosome via a multistep, elongation factor-Tu dependent process. Subsequently, tRNA molecules, bound at the peptidyl site and A site, fluctuate between two configurations assigned as classical and hybrid states. The lifetime of classical and hybrid states, measured for complexes carrying aa-tRNA and peptidyl-tRNA at the A site, shows that peptide bond formation decreases the lifetime of the classical-state tRNA configuration by ≈6-fold. These data suggest that the growing peptide chain plays a role in modulating fluctuations between hybrid and classical states. Single-molecule fluorescence resonance energy transfer was also used to observe aa-tRNA accommodation coupled with elongation factor G-mediated translocation. Dynamic rearrangements in tRNA configuration are also observed subsequent to the translocation reaction. This work underscores the importance of dynamics in ribosome function and demonstrates single-particle enzymology in a system of more than two components.
Sequential shape-and-solder-directed self-assembly of functional microsystems
Authors: Zheng Wei , Buhlmann Philippe , Jacobs Heiko O.
Published: August 2004

We demonstrate the fabrication of packaged microsystems that contain active semiconductor devices and passive components by using a directed self-assembly technique. The directed self-assembly is accomplished by combining geometrical shape recognition with site-specific binding involving liquid solder. Microfabricated components with matching complementary shapes, circuits, and liquid solder-coated areas were suspended in ethylene glycol and agitated by using a turbulent liquid flow to initiate the self-assembly. Microsystems were obtained by sequentially adding components of different types. Six hundred AlGaInP/GaAs light-emitting diode segments with a chip size of 200 μm were assembled onto device carriers with a yield of 100% in 2 min. Packaged light-emitting diodes formed with yields exceeding 97% as a result of two self-assembly steps in 4 min. This self-assembly procedure, based on geometrical shape recognition and subsequent binding to form mechanical and electrical connections, provides a high distinguishing power between different components and a route to nonrobotic parallel assembly of electrically functional hybrid microsystems in three dimensions.
Firing properties of dopamine neurons in freely moving dopamine-deficient mice: Effects of dopamine receptor activation and anesthesia
Authors: Robinson Siobhan , Smith David M. , Mizumori Sheri J. Y. , Palmiter Richard D.
Published: August 2004

To examine the regulation of midbrain dopamine neurons, recordings were obtained from single neurons of freely moving, genetically engineered dopamine-deficient (DD) mice. DD mice were tested without dopamine signaling (basal state) and with endogenous dopamine signaling (after L-dopa administration). In the basal state, when dopamine concentration in DD mice is <1% of that in control animals, the firing properties of midbrain dopamine neurons were remarkably similar among genotypes. However, L-dopa treatment, which restores dopamine and feeding and locomotor behavior in DD mice, profoundly inhibited the firing rate and bursting of dopamine neurons in DD mice. In addition, dopamine neurons in DD mice were hypersensitive to the dopamine receptor agonists quinpirole and SKF 81297. Anesthesia markedly reduced the firing rate of dopamine neurons in DD mice but did not significantly decrease the firing rate in control dopamine neurons. These data suggest that restoration of endogenous dopamine signaling activates hypersensitive long-loop feedback pathways that serve to limit dopamine release and underscore the importance of recording from awake animals.
Microfluidic glucose stimulation reveals limited coordination of intracellular Ca
2+
activity oscillations in pancreatic islets
Authors: Rocheleau Jonathan V. , Walker Glenn M. , Head W. Steven , McGuinness Owen P. , Piston David W.
Published: August 2004

The pancreatic islet is a functional microorgan involved in maintaining normoglycemia through regulated secretion of insulin and other hormones. Extracellular glucose stimulates insulin secretion from islet β cells through an increase in redox state, which can be measured by NAD(P)H autofluorescence. Glucose concentrations over ≈7 mM generate synchronous oscillations in β cell intracellular Ca
2+
concentration ([Ca
2+
]
i
), which lead to pulsatile insulin secretion. Prevailing models assume that the pancreatic islet acts as a functional syncytium, and the whole islet [Ca
2+
]
i
response has been modeled in terms of islet bursting and pacemaker models. To test these models, we developed a microfluidic device capable of partially stimulating an islet, while allowing observation of the NAD(P)H and [Ca
2+
]
i
responses. We show that β cell [Ca
2+
]
i
oscillations occur only within regions stimulated with more than ≈6.6 mM glucose. Furthermore, we show that tolbutamide, an antagonist of the ATP-sensitive K
+
channel, allows these oscillations to travel farther into the nonstimulated regions of the islet. Our approach shows that the extent of Ca
2+
propagation across the islet depends on a delicate interaction between the degree of coupling and the extent of ATP-sensitive K
+
-channel activation and illustrates an experimental paradigm that will have utility for many other biological systems.
A nonsense mutation in the gene encoding a zebrafish myosin VI isoform causes defects in hair-cell mechanotransduction
Authors: Kappler James A. , Starr Catherine J. , Chan Dylan K. , Kollmar Richard , Hudspeth A. J.
Published: August 2004

In a three-generation screen of chemically mutagenized zebrafish, we identified a group of mutations that affect the development and function of hair cells, the mechanically sensitive cells of the inner ear and lateral-line organ. One mutant line,
ru920
, was discovered in a behavioral screen for defects in the acoustically evoked escape response. Despite apparently normal numbers of hair cells, mutants lack an inner-ear microphonic potential and exhibit reduced labeling of hair cells by a fluorophore that traverses transduction channels. This hair-cell-specific phenotype suggested a defect in the mechanoelectrical transduction apparatus. Positional cloning revealed that the recessive mutation introduces a premature stop codon in the ORF of
myosin6b
(
myo6b
), one of the two zebrafish orthologs of the human gene
myosin VI
. The
ru920
line therefore provides an animal model with which to study the role of class VI myosin proteins in mechanotransduction.
Pollen limitation causes an Allee effect in a wind-pollinated invasive grass (
Spartina alterniflora
)
Authors: Davis Heather G. , Taylor Caz M. , Lambrinos John G. , Strong Donald R.
Published: August 2004

It is usually assumed that pollen availability does not limit reproduction in wind-pollinated plants. Little evidence either supporting or contradicting this assumption exists, despite the importance of seed production to population persistence and growth. We investigated the role of pollen limitation in an invasive estuarine grass (
Spartina alterniflora
), with a manipulative pollen supplementation and exclusion experiment in areas of high population density and at the low-density leading edge of the invasion. We also quantified pollen deposition rates on stigmas and pollen traps along a windward to leeward gradient. We found pollen impoverishment at the low-density leading edge of a large invasion, causing an 8-fold reduction in seed set. We found 9-fold more pollen on stigmas of high-density plants than on those of low-density plants. Pollen deposition rates on stigmas and traps did not increase downwind of low-density plants but did increase downwind of high-density plants and dropped off precipitously across a gap that lacked pollen donors. The delay of appreciable numbers of seed caused by pollen limitation persists for decades until vegetative growth coalesces plants into continuous meadows, and this Allee effect has slowed the rate of spread of the invasion.
The immune regulatory protein B7-H3 promotes osteoblast differentiation and bone mineralization
Authors: Suh W.-K. , Wang S. X. , Jheon A. H. , Moreno L. , Yoshinaga S. K. , Ganss B. , Sodek J. , Grynpas M. D. , Mak T. W.
Published: August 2004

B7-H3, a member of the B7 family of the Ig superfamily proteins, is expressed on the surface of the antigen-presenting cells and down-regulates T cell functions by engaging an unknown counterreceptor on T cells. Although B7-H3 is ubiquitously expressed, its potential nonimmune functions have not been addressed. We found that B7-H3 is highly expressed in developing bones during embryogenesis and that its expression increases as osteoblast precursor cells differentiate into mature osteoblasts.In vitrobone formation by osteoblastic cells was inhibited when B7-H3 function was interrupted by the soluble recombinant protein B7-H3-Fc. Analysis of calvarial cells derived from neonatal B7-H3 knockout (KO) mice revealed normal numbers of osteoblast precursor cells possessing a normal proliferative capacity. However, the B7-H3-deficient calvarial cells exhibited impaired osteogenic differentiation, resulting in decreased mineralized bone formationin vitro. These results suggest that B7-H3 is required for the later phase of osteoblast differentiation. Although B7-H3 KO mice had no gross skeletal abnormalities, they displayed a lower bone mineral density in cortical (but not trabecular) bones compared with WT controls. Consistent with the reduced bone mineral density, the femurs of B7-H3 KO mice were more susceptible to bone fracture compared with those of WT mice. Taken together, these results indicate that B7-H3 and its unknown counterreceptor play a positive regulatory role in bone formation. In addition, our findings identified B7-H3 as another molecule that has a dual role in the bone-immune interface.
Dynamic first pass 3D EPI of the prostate: accuracy in tumor location
Authors: Storaas T. , Gjesdal K.‐I. , Svindland A. , Viktil E. , Geitung J. T
Published: August 2004

Purpose: To evaluate the potential of dynamic contrast enhanced (DCE) 3D EPI in the location of prostate cancer.

Material and Methods: A DCE 3D EPI scan was included in the magnetic resonance imaging protocol for prostate examination. Twenty‐eight patients who subsequently underwent radical prostatectomy were included in the study. T2‐weighted (T2W) Turbo Spin Echo (TSE) images were initially evaluated by two radiologists. Parametric images reflecting contrast enhancement were added and new evaluations performed. The results were compared with histology from resected specimens. Accuracies and interobserver agreements were calculated.

Results: Interobserver agreement was κw=49±3% for the T2W technique and κw=30±3% for the combined techniques. No statistically significant advantages were found for location of tumor in the prostate or in the seminal vesicles by adding the DCE information.

Conclusion: DCE 3D EPI did not improve tumor location compared with that of T2W TSE images. Further investigation is needed on how best to exploit the DCE technique.
Whole body magnetic resonance imaging in the diagnosis of parsonage turner syndrome
Authors: Ryan M. , Twair A. , Nelson E. , Brennan D. , Eustace S.
Published: August 2004

Purpose: To describe magnetic resonance imaging (MRI) findings in patients with suspected Parsonage Turner syndrome and to emphasize the value of an additional whole body MR scan to improve specificity of this diagnosis.

Material and Methods: Three patients with proven Parsonage Turner syndrome referred for conventional MRI of the shoulder girdle and additional whole body turboSTIR MRI were included for study.

Results: In each case, imaging revealed edema in the muscles of the shoulder girdle. Whole body turboSTIR MRI scan confirmed localized unilateral changes in each case improving specificity and confidence in the diagnosis of Parsonage Turner syndrome in each case.

Conclusion: Whole body turboSTIR MR imaging is a useful diagnostic tool in the evaluation of patients with suspected Parsonage Turner syndrome. Inclusion of the brain, neck, brachial plexus, and extremity musculature at whole body imaging allows differentiation from polymyositis and elimination of additional causes of shoulder girdle pain and weakness including gross lesions in the brain, neck, and brachial plexus by a single non‐invasive study.
Long‐term MRI findings in operated rotator cuff tear
Authors: Kyrölä K. , Niemitukia L. , Jaroma H. , Väätäinen U.
Published: August 2004

Purpose: To describe magnetic resonance imaging (MRI) findings at long‐term follow‐up after rotator cuff (RC) tear using standard MRI sequences without fat saturation.

Material and Methods: Twenty‐eight patients aged 55.8±7.6 underwent MRI examination 4.6±2.1 years after surgery for RC tear. Standard sequences in oblique coronal, oblique sagittal, and axial planes were obtained. The RC, including re‐tears and tendon degeneration, was independently evaluated by two observers. Thickness of the supraspinatus tendon and narrowing of the subacromial space were measured. The clinical outcome was evaluated with the Constant score and compared with the MRI findings.

Results: The RC tear was traumatic in 18 (64%) patients and degenerative in 10 (36%). At follow‐up, 11 (39%) had normal RC tendons with good clinical outcome. Four (14%) patients had painful tendinosis without RC tear. A full‐thickness RC tear was found in 7 (25%) patients and a partial tear in 6 (21%). In one patient with a full‐thickness tear, and in two with partial tear, tendinosis was found in another of the RC tendons. The subacromial space was narrowed in 13 (46%) of the patients. A narrowing of the subacromial space correlated with re‐tear ( P<0.05).

Conclusions: The RC may be evaluated with standard MRI sequences without fat saturation at long‐term follow‐up. A normal appearance of the RC is correlated with good clinical outcome, while re‐tear and tendinosis are associated with pain.
Biochemical and cytologic analysis of cystic contents in benign non‐parasitic symptomatic hepatic cysts before and after ethanol sclerotherapy
Authors: Larssen T. B. , Rørvik J. , Horn A. , Karwinski B. , Skadberg Ø. , Pedersen O. M. , Rosendahl K.
Published: August 2004

Purpose: To examine the fluid of liver cysts by cytologic and biochemical analysis before and after ethanol sclerotherapy in order to explore the etiology of cystic fluid reproduction after sclerotherapy.

Material and Methods: The contents of 11 cysts in 11 patients were examined on the day of sclerotherapy, and 2–8 (mean 4.5) days later, and analysed for cytologic and biochemical parameters.

Results: Cytologic signs of acute or subacute inflammatory reaction were absent before and present in all cysts after sclerotherapy. Biochemical parameters reflecting the acute inflammatory reaction (CRP, orosomucoid and haptoglobine), changes in capillary permeability (protein, albumin), and the cystic epithelial function (bilirubin, alkaline phosphatase) were significantly elevated after sclerotherapy.

Conclusion: The post‐sclerotherapy fluid production is probably due to an inflammatory reaction. This may explain the success of performing sclerotherapy in one single session.
Treatment Utilization by Women with PTSD and Substance Dependence
Authors: Najavits Lisa M. , Sullivan Tami P. , Schmitz Martha , Weiss Roger D. , Lee Catherine S. N.
Published: August 2004

This study reports the treatment utilization of 77 women with post‐traumatic stress disorder (PTSD) and substance dependence in three areas: lifetime utilization, past thirty days utilization, and perceived helpfulness/harmfulness of current treatments. Results indicated high lifetime treatment utilization overall, yet, for one subgroup, no treatment exposure at all. Most current treatments were focused on SA, in striking contrast to participants' preference: over 80% would choose either combined SA/PTSD treatment or PTSD‐alone treatment. The most common treatments were individual therapy, medication, and hospitalization. Some treatments were perceived as harmful by some participants. The discussion addresses how to help patients obtain needed treatments.
Differences in Peripheral Noradrenergic Function among Actively Drinking and Abstinent Alcohol‐dependent Individuals
Authors: Patkar Ashwin A. , Marsden Charles A. , Naik Prakash C. , Kendall David A. , Gopalakrishnan Raman , Vergare Michael J. , Weinstein Stephen P.
Published: August 2004

We examined whether excessive alcohol consumption was related to changes in plasma levels of noradrenaline (NA) and whether these changes recover following abstinence. We also explored whether there were differences in NA levels between Type I and Type II alcoholics and controls during active drinking and abstinence. Plasma concentrations of NA were determined in (1) 27 Caucasian men with alcohol dependence who were regularly drinking (active drinkers) within 24 hours of hospitalization, (2) 29 Caucasian alcohol‐dependent men who were in remission (abstinent for a minimum of three months), and (3) 28 race‐ and gender‐matched healthy controls. NA concentrations were significantly higher in actively drinking alcohol‐dependent subjects compared to those in remission and controls. While Type I and Type II alcoholic individuals differed across clinical measures, NA levels were similar in the two subtypes. Both subtypes showed an elevation in NA levels during active drinking compared to controls, but NA levels did not differ between the two subtypes and controls during remission. The findings indicate that chronic exposure to alcohol may lead to disturbances in NA activity that may manifest in early abstinence. However, the changes in NA activity appears to normalize after a longer period of abstinence. Alterations in NA activity do not seem to be specific for Type I or Type II subtypes of alcoholism.
Depressive Symptoms in Adolescents during Residential Treatment for Substance Use Disorders
Authors: Subramaniam Geetha A. , Lewis Lindy L. , Stitzer Maxine L. , Fishman Marc J.
Published: August 2004

This study examines the demographic and clinical correlates and time course of depressive symptoms among abstinent adolescents with substance use disorders (SUD) during residential treatment. Fifty‐six adolescents were administered the Beck Depression Inventory at Weeks 1, 3, and 5 of residential treatment for SUD. Clinically significant depression persisted in a substantial minority at the time of discharge. Shorter length of stay patients reported higher baseline scores and a significant decline by Week 3. Longer length of stay patients showed significant decline in scores only at Week 5. Females, Caucasians, and high frequency cocaine) opiates users had elevated depressive symptoms, while those with shorter duration of abstinence did not.
Gender Differences in Indices of Opioid Dependency and Medical Comorbidity in a Population of Hospitalized HIV‐Infected African‐Americans
Authors: Boyd Susan J. , Thomas‐Gosain Neena F. , Umbricht Annie , Tucker Marvin J. , Leslie Jo M. , Chaisson Richard E. , Preston Kenzie L.
Published: August 2004

We examined gender differences in drug use patterns and in medical presentation among 520 hospitalized, HIV‐infected African‐Americans. Substance abuse history was self‐reported, and medical data were obtained by chart review. Overall, 321 (65%) reported ever having used heroin, with equivalent rates in men and women. Women were more likely to report current use, to have sought treatment, and tended to feel more dependent on heroin than men. Among heroin users, women were more likely to be admitted for conditions related to drug use, rather than AIDS, and to have CD4 counts >200/mm3. These gender differences in opioid dependency and medical comorbidity may indicate a need for alternative treatment approaches for men and women.
Stopping Illicit Drug Use Without Treatment: Any Relation to Frequency of Drug Use?
Authors: Cunningham John A.
Published: August 2004

Using data from a large, representative survey of the U.S. population, the relation between frequency of prior drug use and treatment utilization was explored. As was hypothesized, the more frequently former drug users had taken an illicit drug, the more likely they were to have accessed treatment. This relationship was true for all illicit drug classes.
Sensitization to the Psychosis‐Inducing Effects of Cocaine Compared with Measures of Cocaine Craving and Cue Reactivity
Authors: Reid Malcolm S. , Ciplet Debra , O'Leary Siobhan , Branchey Marc , Buydens‐Branchey Laure , Angrist Burt
Published: August 2004

A previous study has suggested that sensitization to the psychosis‐inducing effects of cocaine may be a marker of vulnerability to relapse in cocaine addiction. In this report, cocaine‐dependent subjects participating in a study on naturally occurring and cue‐induced cocaine craving were interviewed about prior experience of cocaine‐induced psychosis and the degree to which this effect had become more frequent or severe or had occurred at lower cumulative doses. Sensitization to cocaine‐induced psychosis was negatively correlated with baseline measures of drug dependence severity and indices of cocaine craving over the preceding 24 hours but not with measures of cocaine cue reactivity.
Radixin deficiency causes deafness associated with progressive degeneration of cochlear stereocilia
Authors: Kitajiri Shin-ichiro , Fukumoto Kanehisa , Hata Masaki , Sasaki Hiroyuki , Katsuno Tatsuya , Nakagawa Takayuki , Ito Juichi , Tsukita Shoichiro , Tsukita Sachiko
Published: August 2004

Ezrin/radixin/moesin (ERM) proteins cross-link actin filaments to plasma membranes to integrate the function of cortical layers, especially microvilli. We found that in cochlear and vestibular sensory hair cells of adult wild-type mice, radixin was specifically enriched in stereocilia, specially developed giant microvilli, and that radixin-deficient (Rdx−/−) adult mice exhibited deafness but no obvious vestibular dysfunction. Before the age of hearing onset (∼2 wk), in the cochlea and vestibule of Rdx−/− mice, stereocilia developed normally in which ezrin was concentrated. As these Rdx−/− mice grew, ezrin-based cochlear stereocilia progressively degenerated, causing deafness, whereas ezrin-based vestibular stereocilia were maintained normally in adult Rdx−/− mice. Thus, we concluded that radixin is indispensable for the hearing ability in mice through the maintenance of cochlear stereocilia, once developed. In Rdx−/− mice, ezrin appeared to compensate for radixin deficiency in terms of the development of cochlear stereocilia and the development/maintenance of vestibular stereocilia. These findings indicated the existence of complicate functional redundancy in situ among ERM proteins.
Raf-1 activation disrupts its binding to keratins during cell stress
Authors: Ku Nam-On , Fu Haian , Omary M. Bishr
Published: August 2004

Keratins 8 and 18 (K8/18) heteropolymers may regulate cell signaling via the known K18 association with 14-3-3 proteins and 14-3-3 association with Raf-1 kinase. We characterized Raf–keratin–14-3-3 associations and show that Raf associates directly with K8, independent of Raf kinase activity or Ras–Raf interaction, and that K18 is a Raf physiologic substrate. Raf activation during oxidative and toxin exposure in cultured cells and animals disrupt keratin–Raf association in a phosphorylation-dependent manner. Mutational analysis showed that 14-3-3 residues that are essential for Raf binding also regulate 14-3-3–keratin association. Similarly, Raf phosphorylation sites that are important for binding to 14-3-3 are also essential for Raf binding to K8/18. Therefore, keratins may modulate some aspects of Raf signaling under basal conditions via sequestration by K8, akin to Raf–14-3-3 binding. Keratin-bound Raf kinase is released upon Raf hyperphosphorylation and activation during oxidative and other stresses.
A Critical Role of Tropomyosins in TGF-β Regulation of the Actin Cytoskeleton and Cell Motility in Epithelial Cells
Authors: Bakin Andrei V. , Safina Alfiya , Rinehart Cammie , Daroqui Cecilia , Darbary Huferesh , Helfman David M.
Published: August 2004

We have investigated transforming growth factor beta (TGF-β)–mediated induction of actin stress fibers in normal and metastatic epithelial cells. We found that stress fiber formation requires de novo protein synthesis, p38Mapk and Smad signaling. We show that TGF-β via Smad and p38Mapk up-regulates expression of actin-binding proteins including high-molecular-weight tropomyosins, α-actinin and calponin h2. We demonstrate that, among these proteins, tropomyosins are both necessary and sufficient for TGF-β induction of stress fibers. Silencing of tropomyosins with short interfering RNAs (siRNAs) blocks stress fiber assembly, whereas ectopic expression of tropomyosins results in stress fibers. Ectopic-expression and siRNA experiments show that Smads mediate induction of tropomyosins and stress fibers. Interestingly, TGF-β induction of stress fibers was not accompanied by changes in the levels of cofilin phosphorylation. TGF-β induction of tropomyosins and stress fibers are significantly inhibited by Ras-ERK signaling in metastatic breast cancer cells. Inhibition of the Ras-ERK pathway restores TGF-β induction of tropomyosins and stress fibers and thereby reduces cell motility. These results suggest that induction of tropomyosins and stress fibers play an essential role in TGF-β control of cell motility, and the loss of this TGF-β response is a critical step in the acquisition of metastatic phenotype by tumor cells.
Toc12, a Novel Subunit of the Intermembrane Space Preprotein Translocon of Chloroplasts
Authors: Becker Thomas , Hritz Jozef , Vogel Markus , Caliebe Alexander , Bukau Bernd , Soll Jürgen , Schleiff Enrico
Published: August 2004

Translocation of proteins across membranes is essential for the biogenesis of each cell and is achieved by proteinaceous complexes. We analyzed the translocation complex of the intermembrane space from chloroplasts and identified a 12-kDa protein associated with the Toc machinery. Toc12 is an outer envelope protein exposing a soluble domain into the intermembrane space. Toc12 contains a J-domain and stimulates the ATPase activity of DnaK. The conformational stability and the ability to stimulate Hsp70 are dependent on a disulfide bridge within the loop region of the J-domain, suggesting a redox-regulated activation of the chaperone. Toc12 is associated with Toc64 and Tic22. Its J-domain recruits the Hsp70 of outer envelope membrane to the intermembrane space translocon and facilitates its interaction to the preprotein.
Exercise and Life‐Satisfactory‐Fitness: Complementary Strategies in the Prevention and Rehabilitation of Illnesses
Authors: Jennen Christiane , Uhlenbruck Gerhard
Published: August 2004

Moderate training of an endurance nature, but also other exercise activities, not only has a preventive effect on various illnesses and pre‐illness states such as the metabolic syndrome and cancer, but is also effective in treating patients in the rehabilitation phase after illness, e.g. cardiovascular or cancer. Our investigation demonstrates that even low level physical activity has a very good preventive effect too, which is enhanced when it is accompanied by mental activity and psychological well‐being. In total, we investigated 13 000 people on the basis of socio‐economic panel polls with respect to life contentment, health status and leisure‐time activities. Life contentment is positively linked to contentment with labor, which seems to be an essential aspect with regard to the increasing number of unemployed people in Europe. The second important factor is health‐promoting activities during leisure time. Exercise, especially, has a significant influence on life satisfaction as a feeling of physical fitness feeling is regarded as synonymous with good health. The results underline the psycho‐neuroimmunological network, which stabilizes our health and shows that different activities in older adults have a significant effect on the aging process and age‐related illnesses. Besides the various activities that are important in this arena, namely muscle and mental mobility (‘brawn and brain’), a third component must be taken into consideration: life contentment in the form of a successful retrospective view and a positive outlook, embedded in a psychosocial family environment (‘brood’) and integrated in a stress‐free biotope, where life does make sense. Alternative and complementary strategies should be considered in light of these three aspects when we think about additional anti‐inflammatory strategies in preventing diseases or treating them and their relapses.Sport has made a few healthy people ill, but sport has also made a good few of ill people healthy! (Gerhard Uhlenbruck, Aphorisms)
Giant Intracranial Aneurysms of the Anterior Circulation
Authors: Lavyne Michael H. , Jonathan Kleefield , Davis Kenneth R. , Ojemann Robert G. , Crowell Robert M.
Published: August 2004

The computed tomography (CT) characteristics and clinical features of giant (globoid) aneurysms of the anterior circulation are reviewed. These lesions appear on the CT scan as smoothly encapsulated ovoid masses, within which a partially patent lumen is seen after the infusion of iodinated contrast material. With careful analysis of the CT scan it may be possible to differentiate giant internal carotid artery, anterior cerebral artery, and middle cerebral artery aneurysms from other parasellar and hemispheric lesions.
Visual Evoked Potentials in Hydrocephalus: Relationship to Head Size, Shunting, and Mental Development
Authors: Norman A. Guthkelch , Robert J. Sclabassi , Robert P. Hirsch , John K. Vries
Published: August 2004

Flash-evoked visual cortical potentials were measured in 54 infants and children with symptomatic hydrocephalus; 54 shunted, asymptomatic infants and children; and 57 controls. All patients were evaluated for head size, mental development, and history of infection of the nervous system. Hydrocephalic infants up to 60 weeks of conceptional age showed significant changes in the maturation curve of the latency to the main positive peak Psub2 (P100), particularly when their hydrocephalus was associated with an enlarged head or with infection. Older children of normal mental development presenting with acute hydrocephalus of recent onset had normal latencies to Psub2. Some persistent ventriculomegaly after shunting was also compatible with normal visual evoked potentials (VEPs). After shunting, the latency to Psub2 became normal in most of the patients who showed normal mental development, whereas retarded hydrocephalic children of all ages continued to have abnormal VEPs.
Intracranial Meningioma Unmasked by Elective General Anesthesia: Report of Three Cases
Authors: Henry A. Young , Howard Smith , Susan A. Gregory , John Gleave
Published: August 2004

Three cases of intracranial meningioma unmasked by elective general anesthesia are reported. In each case, the meningioma was either asymptomatic or so subtly symptomatic that no suspicion of intracranial tumor had been entertained preoperatively. Each patient presented with failure to wake up after routine general anesthesia for a nonneurosurgical procedure. The management of unexplained failure to wake up after uncomplicated general anesthesia is discussed. Early computed tomographic scanning and neurosurgical consultation are suggested in such situations.
Cavernous Hemangioma with Bone Formation in a Child: Case Report
Authors: Takeyoshi Shimoji , Noboru Murakami , Akira Shimizu , Kiyoshi Sato , Shozo Ishii
Published: August 2004

A 13-year-old girl suffering from seizures who was found to have hemangioma calcificans in the frontal lobe was surgically treated. The favorable postoperative course of our patient as well as reported cases suggest early excision of the lesion if it is located in an accessible area. Histological examination confirmed ossification with marrow in the lesion. The literature regarding ossification in the brain is discussed briefly.
Association of Intracranial Aneurysm and Arteriovenous Malformation in Childhood
Authors: John R. Østergaard
Published: August 2004

The simultaneous occurrence in the same patient of an intracranial saccular aneurysm and an arteriovenous malformation (AVM) is a well-known phenomenon. Usually the aneurysms are related anatomically to the arteries supplying the AVM, and it is generally accepted that the aneurysms are caused by hemodynamic stresses resulting from the presence of an AVM. Because patients with both an AVM and an aneurysm are older than those presenting with an AVM alone, a time factor seems essential in the development of the aneurysm accompanying an AVM. In this article, the case reports of two children are presented. They both had a symptom-producing AVM and an attendant saccular aneurysm. The malformations were anatomically closely related and the significance of hemodynamic stresses in the development of the aneurysms cannot be neglected. However, in these two cases, the time factor obviously cannot be of vital importance. Therefore, another factor, possibly in the form of a vascular collagen defect, may be suspected as essential in the formation of aneurysms during childhood. The character of this defect is briefly discussed.
Computer Simulation for the Stereotactic Placement of Interstitial Radionuclide Sources into Computed Tomography-defined Tumor Volumes
Authors: Patrick J. Kelly , Bruce A. Kall , Stephan Goerss
Published: August 2004

This report describes a method for the preoperative determination of radioactive interstitial source placement within computed tomography (CT)-defined tumor boundaries. The method utilizes CT data obtained under stereotactic conditions. Tumor boundaries are digitized from CT slices and are retained in a three-dimensional computer matrix. A solid tumor volume is created by an interpolation program and may be sliced orthogonal to any specific stereotactic surgical view line. The surgeon may simulate radioactive source placement within the slices and view the resultant isodose configuration against tumor contours on successive slices. Once the best source placement has been determined, the computer outputs the mechanical adjustments that will be necessary on a stereotactic frame located in the operating room for the stereotactic placement of each source and gives the length of each source. Sources are stereotactically implanted utilizing a double-catheter afterloading technique.
Composite Autogeneic Human Cranioplasty: Frozen Skull Supplemented with Fresh Iliac Corticocancellous Bone
Authors: Prolo Donald J. , Oklund Sally A.
Published: August 2004

Skull totally exteriorized during craniotomy becomes nonviable. Resorption of the reimplanted cranial section occurs variably according to its treatment, the properties of the recipient bed, and the metabolic conditions of the host. Neurosurgeons commonly deep freeze autogeneic skull for preservation before delayed autogeneic cranioplasty. Aseptic necrosis commonly follows replacement of the autograft in its former cranial bed. This clinical study of six patients represents an attempt to block this destructive resorption by supplementing the frozen autograft with fresh corticocancellous autogeneic ilium. Observations of these patients ranging in age from 12 to 52 years support the following conclusions: (a) Osteogenesis was not enhanced by the addition of fresh corticocancellous bone to the frozen autoimplant. (b) The period of time that the autoimplant was frozen did not influence its subsequent biological behavior after cranioplasty. (c) Sterilization with ethylene oxide and in one case additional gamma irradiation did not impair the quality of the implant compared to those not sterilized. (d) Resorption occurred in both frozen and fresh but devitalized autogeneic skull. (e) Autogeneic skull is repaired by osteoconduction rather than by inducing competent perivascular stem cells to become osteogenic. (f) Freezing of autogeneic skull for preservation is practical, acceptable, but suboptimal from the perspectives of cerebral protection and cosmetic reconstruction. (g) The supplementation of the frozen autoimplant with fresh corticocancellous bone increases operating time and patient discomfort without affording additional benefit.
Experimental Carbon Dioxide Laser Brain Lesions and Intracranial Dynamics: Part 1
Authors: Tiznado Ernesto , James Hector E. , Kemper Cecilia , Wood James H.
Published: August 2004

Experimental brain lesions were created in the left parietooccipital cortex of the albino rabbit through the intact dura mater with high radiating carbon dioxide laser energy (40-watt impacts of 0.5-second duration for a total of 4 seconds on a 12.5-mm surface). Behavior, intracranial pressure (ICP), systolic arterial pressure (SAP), central venous pressure (CVP), electroencephalography (EEG), and gross pathology were studied at 2, 6, and 24 hours after the insult at a constant PaCO2 (38-42 torr). Disruption of the blood-brain barrier (Evans blue extravasation) was uniformly seen extending from the impact crater into the surrounding white matter in all groups. The ICP was elevated in shamoperated animals at 2 hours after the impact, and it remained elevated at 6 and 24 hours. The EEG revealed severe slowing with high voltage waves in the insulted left hemisphere. There was no change in mean SAP or CVP when compared to the sham-operated group. In the dexamethasone-pretreated group, there was a reduction of ICP when compared to the untreated group at 24 hours after the insult (P<0.005), but no changes in the gross pathology were noted. (Neurosurgery 16:5–8, 1985)
Brain Stem Auditory Evoked Potentials in Arnold-Chiari Malformation: Possible Prognostic Value and Changes with Surgical Decompression
Authors: Holliday Peter O. , Pillsbury David , Kelly David L. , Dillard Robert
Published: August 2004

Symptomatic Arnold-Chiari malformation (Chiari II) is a recently described clinical entity, the natural history and surgical management of which remain controversial. The brain stem auditory evoked potentials (BAEPs) have been described as abnormal in 50 to 86% of children with myelomeningocele. We present the case of a full-term infant with myelomeningocele, shunted hydrocephalus, and Chiari II malformation who was surgically treated by decompression when she was 3 weeks old. BAEPs recorded immediately after decompression showed dramatic improvement over BAEPs recorded immediately before decompression, an improvement that could not be attributed to maturation of the central nervous system. It is postulated that in further large series the degree of abnormality in BAEPs may be of value in predicting the clinical course of these patients. The current status of BAEPs as they apply to the evaluation of posterior fossa anomalies is reviewed. (Neurosurgery 16:48–53, 1985)
Air Embolism through a Ventriculoatrial Shunt during Posterior Fossa Operation: Case Report
Authors: Nehls Daniel G. , Carter Philip L.
Published: August 2004

An unusual complication of air embolism through a ventriculoatrial shunt occurred in a patient undergoing posterior fossa operation in the sitting position. Because ventriculoatrial shunts are uncommon, this potential complication may not be widely recognized. A case is presented and the clinical aspects are discussed. (Neurosurgery 16:83–84, 1985)
Intracranial Mucocele Mimicking Arachnoid Cyst: Case Report
Authors: Tamas Laszlo B. , Wyler Allen R.
Published: August 2004

We describe a patient presenting with adult onset seizures whose computed tomographic scan was highly suggestive of arachnoid cyst. The cyst was removed by craniotomy and was found to be a mucocele on histological examination. During operation, no connection to the frontal sinus had been found. The very unusual combination of findings and their clinical implications are discussed. (Neurosurgery 16:85–86, 1985)
Cystic Meningiomas: Report of Two Cases
Authors: Aydin Yunus , Yolas Coskun , Konte Hayrettin , Aydin Ismail Hakki
Published: August 2004

Cyst formation with meningioma is extremely rare. Two cases of large peritumoral cystic lesions associated with intracranial meningiomas that simulated astrocytomas are presented. In each of these young patients, the cyst caused misdiagnosis pre- and intraoperatively. However, total excision was accomplished in each case. The pertinent literature is reviewed. (Neurosurgery 16:87–89, 1985)
Thoracic Chordoma in a Patient with Paraparesis and Ivory Vertebral Body
Authors: Schwarz Saul S. , Fisher Winfield S. , Pulliam Morris W. , Weinstein Zelig R.
Published: August 2004

Chordoma arising in the thoracic region is uncommon. Its presentation roentgenographically as an ivory vertebra has not been previously reported. Such a case is described, and a brief review of the incidence and location of spinal chordomas is given. (Neurosurgery 16:100–102, 1985)