Objective: To study interhemispheric interaction between the hand motor areas of both hemispheres through the corpus callosum in myoclonus epilepsy.
Subjects: Five patients with benign myoclonus ...epilepsy and ten age matched normal volunteers.
Methods: We studied effects of a medially directed conditioning stimulus over the right hand motor area on responses in the right first dorsal interosseous muscle to a posteriorly directed test stimulus over the left hand motor area.
Results: In normal subjects, inhibition was evoked at interstimulus intervals (ISIs) of 8–20ms (late inhibition). In contrast, facilitation occurred in patients at ISIs of 4–6ms (early facilitation) with no late inhibition.
Conclusions: The lack of late inhibition in the patients is consistent with the idea that cortical inhibitory interneurones are affected in myoclonus epilepsy. We propose that this releases interhemispheric facilitation from powerful surround inhibition. The consequence is a predominant early facilitation between the hemispheres in patients with myoclonus epilepsy.
To compare motor evoked potentials (MEPs) elicited by short train, monophasic, repetitive transcranial magnetic stimulations (rTMS) with those by short train, biphasic rTMS.
Subjects were 13 healthy ...volunteers. Surface electromyographic (EMG) responses were recorded from the right first dorsal interosseous muscle (FDI) in several different stimulation conditions. We gave both monophasic and biphasic rTMS over the motor cortex at a frequency of 0.5, 1, 2 or 3
Hz. To study excitability changes of the spinal cord, we also performed 3
Hz rTMS at the foramen magnum level Ugawa Y, Uesaka Y, Terao Y, Hanajima R, Kanazawa I. Magnetic stimulation of corticospinal pathways at the foramen magnum level in humans. Ann Neurol 1994;36:618–24. We measured the size and latency of each of 20 MEPs recorded in the different stimulation conditions.
2 or 3
Hz stimulation with either monophasic or biphasic pulses evoked MEPs that gradually increased in amplitude with the later MEPs being significantly larger than the earlier ones. Monophasic rTMS showed much more facilitation than biphasic stimulation, particularly at 3
Hz. Stimulation at the foramen magnum level at 3
Hz elicited fairly constant MEPs.
The enhancement of cortical MEPs with no changes of responses to foramen magnum level stimulation suggests that the facilitation occurred at the motor cortex. We hypothesize that monophasic TMS has a stronger short-term effect during repetitive stimulation than biphasic TMS because monophasic pulses preferentially activate one population of neurons oriented in the same direction so that their effects readily summate. Biphasic pulses in contrast may activate several different populations of neurons (both facilitatory and inhibitory) so that summation of the effects is not so clear as with monophasic pulses. When single stimuli are applied, however, biphasic TMS is thought to be more powerful than monophasic TMS because the peak-to-peak amplitude of stimulus pulse is higher and its duration is longer when the same intensity of stimulation (the same amount of current is stored by the stimulator) is used.
This means that when using rTMS as a therapeutic tool or in research fields, the difference in waveforms of magnetic pulses (monophasic or biphasic) may affect the results.
cDNA encoding a novel phosphodiesterase (PDE) was isolated from a human fetal lung cDNA library and designated PDE10A. The
deduced amino acid sequence contains 779 amino acids, including a putative ...cGMP binding sequence in the amino-terminal portion
of the molecule and a catalytic domain that is 16â47% identical in amino acid sequence to those of other PDE families. Recombinant
PDE10A transfected and expressed in COS-7 cells hydrolyzed cAMP and cGMP with K
m values of 0.26 and 7.2 μ m , respectively, and V
max with cGMP was almost twice that with cAMP. Of the PDE inhibitors tested, dipyridamole was most effective, with IC 50 values of 1.2 and 0.45 μ m for inhibition of cAMP and cGMP hydrolysis, respectively. cGMP inhibited hydrolysis of cAMP, and cAMP inhibited cGMP hydrolysis
with IC 50 values of 14 and 0.39 μ m , respectively. Thus, PDE10A exhibited properties of a cAMP PDE and a cAMP-inhibited cGMP PDE. PDE10A transcripts were particularly
abundant in the putamen and caudate nucleus regions of brain and in thyroid and testis, and in much lower amounts in other
tissues. The PDE10A gene was located on chromosome 6q26 by fluorescent in situ hybridization analysis. PDE10A represents a new member of the PDE superfamily, exhibiting unique kinetic properties and inhibitor
sensitivity.
A series of frequent measurements on a quantum system (Zeno-like measurements) is shown to result in the "purification" of another quantum system in interaction with the former. Even though the ...measurements are performed on the former system, their effect drives the latter into a pure state, irrespectively of its initial (mixed) state, provided certain conditions are satisfied.
AbstractPurpose: To evaluate the usefulness of the combination of the two non-invasive modalities US and MR imaging to diagnose masses in the parotid region.Material and Methods: The US and MR ...findings of 21 patients with parotid masses were analyzed retrospectively by two radiologists without any clinical or histopathological information. The specific points evaluated were location, shape, margin, internal architecture, and intensity level on both US and MR, posterior echo enhancement on US, and capsule-like lining of the tumor on MR.Results: The findings concerning the shape and margin on US and MR were in fairly good agreement. Concerning the findings of the internal architecture, US could reveal the minute structures of the tumor while MR demonstrated differences in the signal intensities of histological tissue types of the various tumors. The posterior echo enhancement on US and the capsule-like lining on MR of the tumors were also useful for the diagnosis.Conclusion: Our results suggest that the combination of US and MR is useful for examining soft tissue masses in the parotid region to make a more accurate diagnosis, and not just differentiate malignant lesions from those which are benign.
To define criteria for CT and US in differentiating cervical lymph node metastases in oral squamous cell carcinoma (SCC).
CT and/or US of 230 metastatic lymph nodes and 228 benign lymph nodes in 147 ...patients with oral SCC were retrospectively evaluated. The CT and US findings of each lymph node were compared with the histopathological findings. A metastasis was defined on CT as a lymph node with rim or heterogeneous enhancement, or measuring 10 mm or more in the short axis, regardless of enhancement pattern, and on US as having definite internal echoes, regardless of size, or without definite internal or hilar echoes, but measuring 10 mm or more in the short axis. A lymph node with hilar echoes or a ratio of the long to short axis (L/S ratio) of 3.5 or more was considered benign. A lymph node failing to comform to any of these categories was termed questionable.
The positive predictive value (PPV) for CT was 90.8% and the negative predictive value (NPV) was 70.4%. However, 65.7% of all lymph nodes could not be classified as either metastastic or benign. PPV for US was 96.5% and NPV was 88.1%. 25.5% of all lymph nodes could not be classified as either metastatic or benign.
Despite limitations in detecting metastases, by including a third category 'questionable' our criteria appear clinically more useful than other current methods based on two groups only.
In tooth development, the oral ectoderm and mesenchyme coordinately and reciprocally interact through the basement membrane for their growth and differentiation to form the proper shape and size of ...the tooth. Laminin alpha 5 subunit-containing laminin-10/11 (LM-511/521) is the major laminin in the tooth germ basement membrane. Here, we have examined the role of laminin alpha 5 (Lama5) in tooth development using laminin alpha 5-null mouse primary dental epithelium and tooth germ organ cultures. Lama5-null mice develop a small tooth germ with defective cusp formation and have reduced proliferation of dental epithelium. Also, cell polarity and formation of the monolayer of the inner dental epithelium are disturbed. The enamel knot, a signaling center for tooth germ development, is defective, and there is a significant reduction of Shh and Fgf4 expression in the dental epithelium. In the absence of laminin alpha 5, the basement membrane in the inner dental epithelium becomes discontinuous. In normal mice, integrin alpha 6 beta 4, a receptor for laminin alpha 5, is strongly localized at the basal layer of the epithelium, whereas in mutant mice, integrin alpha 6 beta 4 is expressed around the cell surface. In primary dental epithelium culture, laminin-10/11 promotes cell growth, spreading, and filopodia-like microspike formation. This promotion is inhibited by anti-integrin alpha 6 and beta 4 antibodies and by phosphatidylinositol 3-kinase inhibitors and dominant negative Rho-GTPase family proteins Cdc42 and Rac. In organ culture, anti-integrin alpha 6 antibody and wortmannin reduce tooth germ size and shape. Our studies demonstrate that laminin alpha 5 is required for the proliferation and polarity of basal epithelial cells and suggest that the interaction between laminin-10/11-integrin alpha 6 beta 4 and the phosphatidylinositol 3-kinase-Cdc42/Rac pathways play an important role in determining the size and shape of tooth germ.
Three-dimensional superconducting actuator is proposed and experimentally proved in this paper. The authors proposed quadruply arranged hybrid magnets, which consist of permanent magnets and ...electromagnets, to realize the three-dimensional magnetic field gradient in the bulk. PC-controlled coil currents change the magnetic field and generate the forces toward arbitrarily directions. HTSC bulk is located at the center and cooled down in the field-cooling manner, which enables the flux pinning. The eight coils are excited to change the magnetic field gradient and the resultant stable point, and the three-dimensional drive of the superconductor becomes possible. The movements of the specimen are shown in the photographs, and the possibility of three-dimensional movements is proved.
The serum concentration of interleukin-8 (IL-8) was measured in 56 patients within six hours of chest pain. Results show that IL-8 appears in the systemic circulation in the active inflammatory phase ...of coronary artery disease, and could thus be considered a marker for leukocyte-mediated tissue damage in patients with acute coronary lesions.
This article discusses a hybrid drive parallel arm driven by cables and cylinders in order to design a compact handling arm, thus enlarging its workspace. Our major objective is to develop a ...dexterous arm capable of controlling six-degree-of-freedom (DOF) motion of heavy materials. The article includes a basic concept of parallel mechanisms with hybrid actuation, comparisons and evaluations of some types of hybrid mechanisms based on its kinematics and statics, and finally introduces a designed prototype arm.
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