Multiple sclerosis manifesting as a Brown-Séquard syndrome.
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Adult↗
Biomedical subjects
I Ozaki
Publications and source records attributed to I Ozaki.
Dipole orientation differs between high frequency oscillations and N20m current sources in human somatosensory evoked magnetic fields to median nerve stimulation.
The dipole orientation of equivalent current source for the high frequency oscillations (HFOs) above 300 Hz and that for the underlying N20m were compared. Somatic magnetic fields were recorded over the left hand somatosensory area to right median nerve stimulation at the wrist with a wide-bandpass (0.1-2000 Hz). The HFOs and underlying N20m were extracted by digital filtering of 300-900 Hz and 1-300 Hz, respectively. We found that the orientation of the HFOs and underlying N20m current sources differs and that the HFO source orientation shows a more divergent pattern than the N20m. These results suggest that the somatosensory HFOs are not generated from the pyramidal cell population in area 3b which produces the underlying N20m and that they may reflect activities of the non-pyramidal neuron population.
Adult↗
Gln27Glu beta2-adrenergic receptor variant is associated with hypertriglyceridemia and the development of fatty liver.
BACKGROUND: Nonalcoholic steatohepatitis (NASH) is associated with the metabolism of lipid, glucose and energy. Beta-adrenergic receptors play an important role in the regulation of energy expenditure, in part, by stimulating lipid mobilization through lipolysis. METHODS: To assess whether it is common for the beta2-adrenergic receptor (B2AR) gene polymorphisms in codons 16 and 27 to play a role in the development of fatty liver, we investigated 251 unrelated healthy Japanese males who were drug-free and showed no signs of heavy drinking. RESULTS: The allelic frequency of B2AR gene mutation in codons 16 and 27 did not differ between obese subjects (BMI>25.0 kg/m(2), n=151) and non-obese subjects (BMI</=25.0 kg/m(2), n=100). The Gly16 homozygotes had a lower high-density lipoprotein cholesterol (HDL-C) level than the Arg16 homozygotes (1.50+/-0.4 vs. 1.32+/-0.3 mmol/l, p=0.014). However, no significant association with fatty liver was observed in the Gly16 allele frequency. The Gln27Glu27 heterozygotes showed higher concentrations of serum triglycerides (TG) than the Gln27Gln27 homozygotes (1.62+/-0.93 vs. 2.21+/-1.67 mmol/l, p=0.013). This correlation was also observed in all subjects regardless of weight classification. Univariate analysis indicated that subjects with the heterozygous Gln27Glu mutant alleles had a significantly higher prevalence of fatty liver vs. those without the mutation (Glu27 allele frequency, 0.07 vs. 0.12, p=0.047; odds ratio, 1.92; 95% confidence interval, 1.01-3.68). However, multivariate logistic regression models showed the prevalence of fatty liver to be significantly related to the homeostasis model assessment (HOMA) index, BMI, triglyceride and HDL-cholesterol. CONCLUSIONS: These results suggest that the amino-terminal polymorphisms of the beta2-adrenergic receptor gene in codon 27 were associated with hypertryglyceridemia and independent of obesity, and thereby could be involved in the molecular pathogenesis of fatty liver.
Adult↗
Association of the Pro90Ser CD36 mutation with elevated free fatty acid concentrations but not with insulin resistance syndrome in Japanese.
BACKGROUND: CD36 deficiency is reportedly an underlying factor about insulin resistance, defective fatty acid metabolism and hypertriglyceridemia in spontaneously hypertensive rat (SHR), and may be involved in the pathogenesis of insulin resistance and hyperlipidemia in humans. METHODS: We examined 831 adults undergoing health screening. The majority (780) was Pro90 homozygous for the CD36 gene product, but 51 displayed a CD36 mutation (2 homozygous and 49 heterozygous for Ser90). This is the major mutation site involved in CD36 deficiency in Japanese. RESULTS: Among parameters related to insulin resistance, there were no differences in body mass index (BMI), HDL cholesterol, total cholesterol, triglycerides, insulin and insulin resistance index (HOMA IR), or blood pressure between 91 normal subjects (45 male and 46 female) randomly selected from the 780 Pro90 homozygotes and the 51 (29 male and 22 females) CD36-deficient subjects (Ser90 homozygote and Pro90Ser heterozygote). Free fatty acid concentrations, however, were higher in Ser90 CD36 subjects than in Pro90 control subjects. CONCLUSIONS: The CD36Pro90Ser mutation is not necessarily related to the insulin resistance syndrome, but is associated with high free fatty acid concentrations in Japanese.
Adult↗
Electrophysiological changes in diabetic neuropathy: from subclinical alterations to disabling abnormalities.
Clinical spectrum of diabetic neuropathy is variable; it may be asymptomatic, but once established as polyneuropathy, it is irreversible and may finally be disabling. To estimate the prevalence of subclinical diabetic polyneuropathy in the UAE, we undertook a pilot study by means of nerve conduction study (NCS) of peroneal motor and sural sensory studies in 60 diabetics with no symptoms of neuropathy. Neurological examination revealed clinical abnormalities suggesting polyneuropathy in 26 patients, 43% of the patients. NCS revealed abnormal values in 63% of the whole patients. Abnormal NCS was confirmed in 88% of the positive sign group. As to the negative sign group 44% had abnormalities in NCS. Prolonged F-wave latency was seen in 29% in no sign group and in 66% of the patients with positive signs. We found close association between neurological deficit score and abnormalities in NCS. Among various parameter of systemic nerve conduction study in subclinical patients, prolonged F-wave latency seems the commonest abnormality suggesting morphological changes in subclinical diabetic nerve. Decrease in amplitude of compound sensory action potential of sural nerve is another earlier abnormality, which is, then, accompanied by a fall in motor amplitude of peroneal nerve in advanced patients. Recently, our own group of Hirosaki has demonstrated that somatosensory central conduction time (CCT) between the spinal cord entry time and the arrival time to the sensory cortex is prolonged in diabetics. This abnormality might be partly responsible for the irreversible sensory deficits of diabetic neuropathy.
Action Potentials↗
Involvement of the Ets-1 gene in overexpression of matrilysin in human hepatocellular carcinoma.
Although matrix metalloproteinases (MMPs) are thought to be involved in the invasion and metastasis of a variety of malignant tumors, including human hepatocellular carcinoma (HCC), the mechanisms for the expression of MMPs in HCC are not known. To understand the mechanism(s) of MMP expression, the expression of matrilysin (MMP-7) and several genes of the Ets transcription factor family was investigated in human HCC and hepatoma-derived cell lines. The role of Ets-1 gene expression in HCC was also studied. Analysis by semiquantitative reverse transcription-PCR revealed that MMP-7 and Ets-1 are overexpressed and closely associated in HCC. To clarify the role of Ets-1, hepatoma cells were transduced with human Ets-1 or targeted with the Ets-1-specific antisense oligonucleotides. Cells stably transduced with the Ets-1 gene showed increased MMP-7 expression compared to parental and mock-transfected cells. Cells targeted with Ets-1-specific antisense oligonucleotides showed reduced expression of MMP-7. Cotransfection of cells with a MMP-7 promoter-reporter gene plasmid and an Ets-1 expression vector yielded an increase in MMP-7 promoter activity in an Ets-1-responsive element-dependent manner. Taken together, these data suggested that the Ets-1 oncogene is up-regulated and involved in the overexpression of MMP-7 in human HCC and may contribute to the progression of HCC.
Aged↗
Peripheral and central conduction abnormalities in diabetes mellitus.
OBJECTIVES: To investigate peripheral and central somatosensory conduction in patients with diabetes. METHODS: The authors recorded sensory nerve action potentials and 5-channel somatosensory evoked potentials (SEPs) with noncephalic reference after median nerve stimulation in 55 patients with diabetes and 41 age- and height-matched normal subjects. The authors determined onset or peak latencies of the Erb's potential (N9) and the spinal N13-P13 and the cortical N20-P20 components, and obtained the central conduction time (CCT) by onset-to-onset and peak-to-peak measurements. RESULTS: Both onset and peak latencies of all SEP components were prolonged in patients with diabetes. The mean onset CCT in the diabetic group was 6.3 +/- 0.5 msec (mean +/- SD)-significantly longer than that in the control group (6.1 +/- 0.2 msec)-whereas no significant difference was found in the peak CCT. The amplitudes of N9 and N13-P13 components (but not N20-P20) were significantly smaller in the diabetic group. The peripheral sensory conduction velocity was also decreased in the diabetic group, but there was no significant correlation between peripheral conduction slowing and the onset of CCT prolongation. CONCLUSIONS: Diabetes affects conductive function in the central as well as peripheral somatosensory pathways. The CCT abnormality does not coincide with lowering of the peripheral sensory conduction. The current results do not favor a hypothesis that a central-peripheral distal axonopathy plays an important role in development of diabetic polyneuropathy.
Adult↗
Stability of N20 onset or peak latency in median somatosensory evoked potentials.
We analyzed onset and peak latencies of the N20 response of median nerve somatosensory evoked potentials (SEPs) in 21 healthy subjects by simultaneous recordings with noncephalic or ear reference from multiple scalp sites. The cortical onset was defined as the fork at which the contralateral parietal and frontal or ipsilateral parietal waves diverged. We found the N20 onset unchanged between noncephalic and ear reference recordings, or among the recordings around the contralateral centroparietal scalp. The N20 peak was prolonged when the recording position moved posteriorly. We suggest that N20 onset latency is more stable than N20 peak.
Adult↗
Ribose 1,5-bisphosphate inhibits fructose-1,6-bisphosphatase in rat kidney cortex.
Fructose-1,6-bisphosphatase is one of the regulatory enzymes of gluconeogenesis in kidney cortex. The effect of ribose 1,5-bisphosphate on fructose-1,6-bisphosphatase purified from rat kidney cortex was studied. Rat kidney cortex, fructose-1,6-bisphosphatase exhibited hyperbolic kinetics with regard to its substrate, but the activity was inhibited by ribose 1,5-bisphosphate at nanomolar concentrations. The inhibitory effect of ribose 1,5-bisphosphate on the fructose-1,6-bisphosphatase was enhanced in the presence of AMP, one of the inhibitors of fructose-1,6-bisphosphatase. Fructose-2,6-bisphosphate, which is an inhibitor of fructose-1,6-bisphosphatase, inhibited rat kidney cortex fructose-1,6-bisphosphatase activities at a low concentration of fructose-1,6-bisphosphate but a high concentration of fructose-1,6-bisphosphate relieved fructose-1,6-bisphosphatase from fructose-2,6-bisphosphate-dependent inhibition. On the contrary, fructose-1,6-bisphosphate was not effective for the recovery of fructose-1,6-bisphosphatase from ribose 1,5-bisphosphate-dependent inhibition. These results suggest that ribose 1,5-bisphosphate is a potent inhibitor and is involved in the regulation of fructose-1,6-bisphosphatase in rat kidney cortex.
Animals↗
Calphostin C-mediated translocation and integration of Bax into mitochondria induces cytochrome c release before mitochondrial dysfunction.
Calphostin C-mediated apoptosis in glioma cells was reported previously to be associated with down-regulation of Bcl-2 and Bcl-xL. In this study, we report that 100 nM calphostin C also induces translocation and integration of monomeric Bax into mitochondrial membrane, followed by cytochrome c release into cytosol and subsequent decrease of mitochondrial inner membrane potential (DeltaPsim) before activation of caspase-3. The integration of monomeric Bax was associated with acquirement of alkali-resistance. The translocated monomeric Bax was partly homodimerized after cytochrome c release and decrease of DeltaPsim. The translocation and homodimerization of Bax, cytochrome c release, and decrease of DeltaPsim were not blocked by 100 microM z-VAD.fmk, a pan-caspase inhibitor, but the homodimerization of Bax and decrease of DeltaPsim were inhibited by 10 microM oligomycin, a mitochondrial F0F1-ATPase inhibitor. Therefore, it would be assumed that mitochondrial release of cytochrome c results from translocation and integration of Bax and is independent of permeability transition of mitochondria and caspase activation, representing a critical step in calphostin C-induced cell death.
Apoptosis↗
Activation of stress-activated protein kinase/c-Jun NH2-terminal kinase and p38 kinase in calphostin C-induced apoptosis requires caspase-3-like proteases but is dispensable for cell death.
Apoptosis was induced in human glioma cell lines by exposure to 100 nM calphostin C, a specific inhibitor of protein kinase C. Calphostin C-induced apoptosis was associated with synchronous down-regulation of Bcl-2 and Bcl-xL as well as activation of caspase-3 but not caspase-1. The exposure to calphostin C led to activation of stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) and p38 kinase and concurrent inhibition of extracellular signal-regulated kinase (ERK). Upstream of ERK, Shc was shown to be activated, but its downstream Raf1 and ERK were inhibited. The pretreatment with acetyl-Tyr-Val-Ala-Asp-aldehyde, a relatively selective inhibitor of caspase-3, or benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (z-VAD.fmk), a broad spectrum caspase inhibitor, similarly inhibited calphostin C-induced activation of SAPK/JNK and p38 kinase as well as apoptotic nuclear damages (chromatin condensation and DNA fragmentation) and cell shrinkage, suggesting that caspase-3 functions upstream of SAPK/JNK and p38 kinase, but did not block calphostin C-induced surface blebbing and cell death. On the other hand, the inhibition of SAPK/JNK by transfection of dominant negative SAPK/JNK and that of p38 kinase by SB203580 induced similar effects on the calphostin C-induced apoptotic phenotypes and cell death as did z-VAD.fmk and acetyl-Tyr-Val-Ala-Asp-aldehyde, but the calphostin C-induced PARP cleavage was not changed, suggesting that SAPK/JNK and p38 kinase are involved in the DNA fragmentation pathway downstream of caspase-3. The present findings suggest, therefore, that the activation of SAPK/JNK and p38 kinase is dispensable for calphostin C-mediated and z-VAD.fmk-resistant cell death.
Amino Acid Chloromethyl Ketones↗
Proteasome inhibitors induce mitochondria-independent apoptosis in human glioma cells.
The proteasome inhibitors lactacystin and AcLLNal induced p53-independent apoptosis in two human glioma cell lines, and the apoptosis was accompanied by up-regulation of immunoreactive wild-type p53, p21Waf1, Mdm2, and p27Kip1. Pretreatment with cycloheximide decreased the induction of cell death independently of p53 protein status, suggesting that the up-regulation of short-lived proteins is associated with proteasome inhibitor-induced apoptosis. Caspase-3-like proteases were activated in the proteasome inhibitor-mediated apoptosis, and the induction of cell death was inhibited more effectively in the presence of z-VAD.fmk than in the presence of Ac-DEVD.fmk, suggesting that caspases other than caspase-3 are involved. Nonetheless, there were no significant alterations in levels of immunoreactive Bcl-2, Bcl-X(L), Bax, Bad, and Bak, nor any evidence of cytochrome c release into cytosol and dissipation of delta(psi)m. Thus, the proteasome inhibitor-induced apoptosis is mediated by a mitochondria-independent mechanism, and the once activated caspase-3 does not cause the cytochrome c release and the delta(psi)m disruption.
Animals↗
Ribozyme-mediated specific gene replacement of the alpha1-antitrypsin gene in human hepatoma cells.
BACKGROUND/AIMS: Some of the mutant forms of cellular proteins not only lose their function, but also cause diseases by their toxic effects. One of the challenging tasks in the field of gene therapy will be "gene replacement" accomplished by inhibiting mutant gene expression and providing normal function of the same gene, simultaneously. Although lung involvement in alpha1-antrypsin (alpha1-AT) deficiency is caused by the lack of alpha1-AT function, the liver involvement is due to the accumulation of the mutated alpha1-AT protein. Therefore, one possible approach to prevent and treat the disease manifestations of alpha1-AT deficiency is to inhibit the expression of the mutated gene and replace it with normally functioning alpha1-AT protein in the liver. METHODS: For the inhibition of alpha1-AT gene expression, panels of alpha1-AT-specific hammerhead ribozymes designed to target different GUC sites in the alpha1-AT mRNA were evaluated in a human hepatoma cell-line, transduced with retroviral vectors which express ribozymes under the control of a human tRNA promoter. A bi-functional vector was also constructed, which contained a functional alpha1-AT ribozyme and was combined with a modified alpha1-AT gene, whose product was engineered to be resistant to the specific alpha1-AT ribozyme. This construct was transduced into target hepatoma cells. RESULTS: The transduced hepatoma cells showed the effective expression of modified alpha1-AT, under the conditions where the endogenous alpha1-AT gene expression was inhibited. CONCLUSION: This ribozyme-mediated, specific gene replacement is a first step in the gene therapy of alpha1-AT deficiency.
Base Sequence↗
Effects of aging on central conduction in somatosensory evoked potentials: evaluation of onset versus peak methods.
OBJECTIVES: To investigate effects of aging on peripheral and central somatosensory conduction, and evaluate onset-to-onset and peak-to-peak measurements of each component and central conduction time (CCT) in somatosensory evoked potentials (SEPs). METHODS: We recorded SEPs with non-cephalic reference from the Erb's point, the posterior (cv 6) and anterior neck, and scalp (Fz and P4) after left median nerve stimulation in 138 normal subjects aged between 20 and 78 years. We determined onset or peak latencies of the Erb's potential (N9), the spinal N13-P13 in cv 6-to-anterior neck montage and the N20-P20 in scalp leads. Onset CCT was defined as a transit time from N13-P13 onset to N20-P20 onset. In each subject, interpeak latencies of the 'N13' component in cv 6-to-Fz montage and the N20-P20 in P4-to-Fz montage were also defined as conventional peak CCT. RESULTS: Using multiregression analysis, we found that the onset or peak latencies of each SEP component were correlated with the subject's height and age. So were the onset CCTs: Onset CCT (in ms) = 2.549+2.041x(height in meters) + 0.005 x (age in years) (P<0.0001). The conventional peak CCTs as well as onset-to-peak durations of the N20-P20 were correlated with the subject's age but not height: Peak CCT(in ms) = 5.458+0.012x (age in years) (P<0.0005). CONCLUSION: Conductive function is affected by normal aging in the central as well as peripheral somatosensory pathways. The peak CCT is more affected by aging than the onset CCT. However, the onset-to-peak duration of the N20-P20 increased by 0.8 ms between the 4th and 7th decades, suggesting that the peak CCT increase in older people reflects the age-related changes in N20-P20 profile but not in the fastest central conduction. We therefore conclude that the onset CCT measurement is preferable to the peak CCT measurement when assessing the central somatosensory conduction.
Adult↗
A novel SV40-based vector successfully transduces and expresses an alpha 1-antitrypsin ribozyme in a human hepatoma-derived cell line.
Alpha 1-antitrypsin (alpha 1AT) deficiency disease is one of the more common hereditary disorders that affects the liver and lung. The liver disease of alpha 1AT deficiency is generally thought to be caused by the accumulation of an abnormal alpha 1AT protein in hepatocytes, whereas the lung disease is thought to be due to a relative lack of the normal protein in the circulation. Therefore, one possible approach to prevent and treat alpha 1AT disease is to both inhibit the expression of the mutated alpha 1AT gene, and to provide a means of synthesizing the normal protein. To do this, we designed specific hammerhead ribozymes that were capable of cleaving the alpha 1AT mRNA at specific sites, and constructed a modified alpha 1AT cDNA not susceptible to ribozyme cleavage. Ribozymes were effective in inhibiting alpha 1AT expression in a human hepatoma cell line using a newly developed simian virus (SV40) vector system. In addition, the hepatoma cell line was stably transduced with a modified alpha 1AT cDNA that was capable of producing wildtype alpha 1AT protein, but was not cleaved by the ribozyme that decreased endogenous alpha 1AT expression. These results suggest that ribozymes can be employed for the specific inhibition for an abnormal alpha 1AT gene product, the first step in designing a gene therapy for the disease. The findings also suggest that the novel SV40-derived vector may represent a fundamental improvement in the gene therapeutic armarmentarium.
Blotting, Northern↗
Activation of protein kinases in canine basilar artery in vasospasm.
Subarachnoid hemorrhage (SAH) often leads to a long-term narrowing of cerebra! artery called vasospasm. To understand the molecular mechanisms in vasospasm, signal transduction of tyrosine kinase pathway and phosphorylation of myosin light chain (MLC) and calponin (CaP) in the basilar artery were studied. Vasospasm was produced in the canine basilar artery by a two-hemorrhage method, and vasocontraction was induced by a local application of KCI or serotonin to the basilar artery after a transclival exposure. Intracellular substrates of tyrosine kinase pathway, including Shc, Rafl, and extracellular-regulated kinases in the basilar artery, were activated after SAH, and the activation of Shc suggests stimulation of signal transductions from tyrosine kinase receptors, G-coupled receptors, or both. The activation of tyrosine kinase pathway in vasospasm also was supported by dose-dependent dilation of the spastic basilar artery on days 0 and 7 by topical application of genistein, a tyrosine kinase inhibitor, and associated marked inhibition of tyrosine phosphorylation of intracellular substrates, including Shc. In addition, the generation of protein kinase M, catalytic fragment of protein kinase C(alpha) (PKC alpha), in vasospasm on days 0 and 7 was inhibited in response to genistein, indicating an inactivation of mu-calpain. It is suggested, therefore, that the reversal of vasospasm by genistein is closely associated with the restoration of intracellular Ca2+ levels. However, the increased activities of Raf1 and extracellular-regulated kinases in vasospasm were declined on day 7 compared with those on day 0 or 2, suggesting that the activation of tyrosine kinase pathway is more closely associated with the early stage of vasospasm than with the late stage of vasospasm. The analysis by pyrophosphate polyacrylamide gel electrophoresis (PPi-PAGE) demonstrated three MLC bands in vasospasm on days 2 and 7, as well as in KCI- and serotonin-induced vasocontraction. Since PPi-PAGE resolves smooth muscle MLC into three bands in the MLC kinase (MLCK)-mediated phosphorylation and into a single band in the PKC-mediated phosphorylation based on the phosphorylation state, the current results suggest that MLC in vasospasm is phosphorylated by MLCK but not by PKC. In basilar artery, CaP was significantly down-regulated, and in addition, significantly phosphorylated on serine and threonine residues only in vasospasm on days 2 and 7. Although the significance of CaP phosphorylations in vivo still is controversial, CaP down-regulation and phosphorylation may attenuate the inhibition of Mg(2+)-ATPase activity by CaP and induce a potential enhancement of smooth muscle contractility in delayed vasospasm. Since CaP is phosphorylated in vivo by PKC, activated PKC in vasospasm may phosphorylate CaP. Thus, SAH stimulates tyrosine kinase pathway to increase intracellular Ca2+ and activate PKC, and the former activates MLCK to phosphorylate MLC, whereas the latter phosphorylates CaP but not MLC.
Animals↗
Assignment of the programmed cell death 4 gene (PDCD4) to human chromosome band 10q24 by in situ hybridization.
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Apoptosis Regulatory Proteins↗
[Multifocal motor neuropathy (MMN)].
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Demyelinating Diseases↗