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  • 1
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: We describe here a sensitive assay method for lysosulfatide (sulfogalactosylsphingosine) in human tissues using HPLC. The method involves extraction of lipids, saponification, isolation using a C18 Sep-Pak column, derivatization with o-phthalaldehyde, and detection of the fluorescent lysosulfatide using HPLC. In control subjects, a small amount of lysosulfatide was detected in the cerebral white matter (9–35 pmol/mg of protein), spinal cord (35 pmol/mg of protein), sciatic nerve (14 pmol/mg of protein), and kidney (∼2 pmol/ mg of protein) but not in the cerebral gray matter and liver. A marked accumulation of the lipid was noted in tissues from six patients with metachromatic leukodystrophy (MLD). The concentration of lysosulfatide was high in the cerebral white matter, spinal cord, and sciatic nerve (223–1,172 pmol/mg of protein). Even in the cerebral gray matter, kidney, and liver, where lysosulfatide was hardly detected in the control sample, a considerable amount (3–45 pmol/mg of protein) accumulated in MLD patients. The concentration and distribution pattern of lysosulfatide were similar to those of galactosylsphingosine (psychosine) accumulated in patients with Krabbe disease. Therefore, the accumulation of lysosulfatide may explain the demyelination in patients with MLD, as is the case with Krabbe disease.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The cDNA for a murine galactocerebrosidase was isolated from a murine testis cDNA library on the basis of its homology with the cDNA for human galactocerebrosidase and a PCR method was used to clone the 5′ end. It has a 2,278-nucleotide sequence including a 2,004-nucleotide open reading frame, which encodes 668 amino acid residues. The identity between the human and murine amino acid sequences was very high, being calculated to be 84%. Sequencing of cDNA from liver of the twitcher mouse revealed a nonsense mutation at codon 339 (TGG → TGA). The most abundant mRNA of the murine galactocerebrosidase gave a 3.6-kb band, which was not detected in twitcher mice. This suggests that the cDNA (2,278 bp) we characterized represents a minor species generated by an alternate poly(A) signal and that most of the mRNA has a much longer 3′-untranslated region. Genome analysis revealed that this mutation was homozygous in the twitcher and heterozygous in the carrier but was not present in normal mice. The normal mouse cDNA but not the mutant cDNA of the galactocerebrosidase transfected into COS1 cells gave rise to an increase in enzymatic activity. We concluded that this mutation results in the deficiency of galactocerebrosidase in the twitcher mouse.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1365-2826
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study was designed to evaluate changes in the hypothalamic somatostatin-growth hormone axis (SRIF–GH axis) in a stress-induced rat model of depression. We exposed male Wistar rats to intermittent walking stress for two weeks, and then measured their spontaneous running activities for 12 days. We divided the rats into the depression-model group and the partial recovery group according to their spontaneous running activities after the termination of exposure to stress. We examined the secretion of GH from the anterior pituitary by injecting human GH-releasing hormone (hGHRH) with intracardiac cannulae or by applying hGHRH or SRIF to isolated anterior pituitaries using a perifusion system. We also determined SRIF content in the stalk-median eminence (SME) and the plasma concentration of GH. In the depression-model group, intracardiac administration of hGHRH caused the enhanced release of GH into plasma, while application of hGHRH or SRIF to the anterior pituitary in vitro had similar effects on GH release in the control and partial recovery groups. Furthermore, the SRIF content was decreased in the SME and the GH concentration was increased in plasma. The partial recovery group gave similar values to the control group. The enhanced response of GH to hGHRH in the depression-model group might have been caused by the reduced content of SRIF in the SME in view of the unchanged response of GH to the infusion of hGHRH or SRIF in the perifusion system.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To elucidate the mechanisms underlying sensorimotor integration, we investigated modulation in the primary (SI) and secondary (SII) somatosensory cortices during the preparatory period of a self-initiated finger extension. Electrical stimulation of the right median nerve was applied continuously, while the subjects performed a self-initiated finger extension and were instructed not to pay attention to the stimulation. The preparatory period was divided into five sub-periods from the onset of the electromyogram to 3000 ms before movement and the magnetoencephalogram signals following stimulation in each sub-period were averaged. Multiple source analysis indicated that the equivalent current dipoles (ECDs) were located in SI and bilateral SII. Although the ECD moment for N20m (the upward deflection peaking at around 20 ms) was not significantly changed, that for P30m (the downward deflection peaking at around 30 m) was significantly smaller in the 0- to −500-ms sub-period than the −2000- to −3000-ms sub-period. As for SII, the ECD moment for the SII ipsilateral to movement showed no significant change, while that for the contralateral SII was significantly larger in the 0- to −500-ms sub-period than the −1500- to −2000-ms or −2000- to −3000-ms sub-period. The opposite effects of movement on SI and SII cortices indicated that these cortical areas play a different role in the function of the sensorimotor integration and are affected differently by the centrifugal process.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 22 (2005), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The go/nogo task is a useful paradigm for recording event-related potentials (ERPs) to investigate the neural mechanisms of response inhibition. In nogo trials, a negative deflection at around 140–300 ms (N2), which has been called the ‘nogo potential’, is elicited at the frontocentral electrodes, compared with ERPs recorded in go trials. In the present study, we investigated the generators of nogo potentials by recording ERPs and by using magnetoencephalography (MEG) simultaneously during somatosensory go/nogo tasks to elucidate the regions involved in generating nogo potentials. ERP data revealed that the amplitude of the nogo-N140 component, which peaked at about 155 ms from frontocentral electrodes, was significantly more negative than that of go-N140. MEG data revealed that a long-latency response peaking at approximately 160 ms, termed nogo-M140 and corresponding to nogo-N140, was recorded in only nogo trials. The equivalent current dipole of nogo-M140 was estimated to lie around the posterior part of the inferior frontal sulci in the prefrontal cortex. These results revealed that both nogo-N140 and nogo-M140 evoked by somatosensory go/nogo tasks were related to the neural activity generated from the prefrontal cortex. Our findings combining MEG and ERPs clarified the spatial and temporal processing related to somato-motor inhibition caused in the posterior part of the inferior frontal sulci in the prefrontal cortex in humans.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To investigate the processing of noxious stimuli within the primary somatosensory cortex (SI), we recorded magnetoencephalography following noxious epidermal electrical stimulation (ES) and innocuous transcutaneous electrical stimulation (TS) applied to the dorsum of the left hand. TS activated two sources sequentially within SI: one in the posterior bank of the central sulcus and another in the crown of the postcentral gyrus, corresponding to Brodmann's areas 3b and 1, respectively. Activities from area 3b consisted of 20- and 30-ms responses. Activities from area 1 consisted of three components peaking at 26, 36 and 49 ms. ES activated one source within SI whose location and orientation were similar to those of the TS-activated area 1 source. Activities from this source consisted of three components peaking at 88, 98 and 109 ms, later by 60 ms than the corresponding TS responses. ES and TS subsequently activated a similar region in the upper bank of the sylvian fissure, corresponding to the secondary somatosensory cortex (SII). The onset latency of the SII activity following ES (109 ms) was later by 29 ms than that of the first SI response (80 ms). Likewise, the onset latency of SII activity following TS (52 ms) was later by 35 ms than that of area 1 of SI (17 ms). Therefore, our results showed that the processing of noxious and innocuous stimuli is similar with respect to the source locations and activation timings within SI and SII except that there were no detectable activations within area 3b following noxious stimulation.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Synchronization and desynchronization of the neural rhythm in the brain play an important role in the orchestration of perception, motor action and conscious experience. Based on the results of electrocorticographic and magnetoencephalographic (MEG) recordings, it has been considered that human rolandic oscillations originate in the anterior bank of the central sulcus (20-Hz rhythm) and the postcentral cortex (10-Hz rhythm): the 20-Hz oscillation is closely related to motor function, while the 10-Hz rhythm is attributed mainly to sensory function. To test whether the rolandic oscillations are functionally relevant to the motor cortical excitability, we examined effects of 1-Hz repetitive transcranial magnetic stimulation (rTMS) of the left primary motor cortex (M1) on movement-related changes of the rolandic oscillations in 12 normal subjects. MEG data recorded during brisk extension of the right index finger in two different sessions (with and without rTMS conditioning) were compared. Motor-evoked potential (MEP) of the right hand muscle was also measured before and after rTMS to assess the motor cortical excitability. We found that 1-Hz rTMS over M1 significantly reduced the movement-related rebound of the 20-Hz oscillation in association with decreased motor cortical excitability. In particular, movement-related rebound of the 20-Hz rhythm was closely tied with motor cortical excitability. These findings further strengthen the notion of functional relevance of 20-Hz cortical oscillation to motor cortical excitability. In the framework of previous studies, the decrease in movement-related rebound may be regarded as a compensatory reaction to the inhibited cortical activity.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1546-1718
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Roberts syndrome is an autosomal recessive disorder characterized by craniofacial anomalies, tetraphocomelia and loss of cohesion at heterochromatic regions of centromeres and the Y chromosome. We identified mutations in a new human gene, ESCO2, associated with Roberts syndrome in 15 kindreds. The ...
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Complementary and genomic DNAs isolated from the fibroblasts of 10 Japanese (7 late infantile, 2 juvenile, and 1 adult form of the disease) and one Caucasian patient with Niemann-Pick disease type C were analyzed for mutations in the NPC1 gene. Fourteen novel mutations were found including small deletions and point mutations. A one-base deletion and a point mutation caused splicing errors. The mutations were not clustered in any particular region of the gene and were found both in and out of the transmembrane domains. Three patients were homozygous, five were compound heterozygous, and the remaining three were suspected of being compound hetrozygous with an unknown error in one of their NPC1 alleles. Of the 14 mutations, the G1553A substitution that caused a splicing error of exon 9 appeared to be relatively common in Japanese patients, because two patients were homozygous and one patient was compound heterozygous for this mutation.
    Type of Medium: Electronic Resource
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