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Biomedical subjects

H Fujimura

Publications and source records attributed to H Fujimura.

At least 73 records · Page 4Linked to original sources
PubMed1997

Block of the cell cycle of the yeast Saccharomyces cerevisiae by tyrphostin, an inhibitor of protein tyrosine kinase.

Tyrphostins are inhibitors of the epidermal growth factor receptor tyrosine kinase. To elucidate the biological function of protein tyrosine kinases in yeast cells, a mutant hypersensitive to tyrphostin was isolated and investigated for its response to the drug. The mutation was recessive and was designated tpt1 for tyrphostin hypersensitive. A tpt1 strain cannot grow in the presence of tyrphostin, implying that a biological process sensitive to tyrphostin is essential for cell growth. Microscopic observation indicated that large-budded cells were accumulated in the presence of the inhibitor. The results suggest the involvement of protein tyrosine phosphorylation in the cell cycle progression of Saccharomyces cerevisiae.

Antifungal Agents↗
PubMed1997

Cognitive function in amyotrophic lateral sclerosis.

Cognitive function in patients with amyotrophic lateral sclerosis (ALS) has drawn recent attention. However, the pathogenesis of cognitive dysfunction in patients with ALS remains uncertain. To explore the underlying mechanism for cognitive dysfunction further, we studied 26 patients with ALS (15 male and 11 female; age from 36 to 67 years) by using neuropsychological batteries, magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT). We also evaluated these patients and an additional 26 age- and sex-matched normal controls using neuropsychological batteries with special attention to the frontal lobe function. On the basis of neuropsychological examination, we classified patients into three groups using cluster analysis. Age, education level and severity were comparable across these subgroups. Neuropathologic examination was subsequently carried out in six patients. Patients in Group 1 and 2 had low scores on all measures compared to patients in Group 3 and normal controls. Patients in Group 1 and 2 had frontal atrophy on MRI and reduced isotope uptake in the frontal region on SPECT, which was more evident in patients in Group 1. On neuropathologic examination, patients in Group 1 showed spongy degeneration and neuronal loss in the frontal lobe. Patients in Group 3 showed no notable pathology in the frontal region. The gradient distribution of the scores for attention and executive function, as well as SPECT findings suggested the presence of a continuum of cognitive disability in patients with ALS corresponding to the pathologic process in the frontal lobe ranging from significant impairment to normality. We, therefore, believe that inattention and executive dysfunction alternatives may evolve in patients with ALS corresponding to the pathologic process in the frontal lobe.

Adult↗
PubMed1997

The effect of dexamethasone on the expression of activated NF-kappa B in adjuvant arthritis.

The transcription factor NF-kappa B plays a significant role in inflammatory diseases. In this study we have investigated the expression of activated NF-kappa B p65 subunit in the rat adjuvant arthritis model in a 28-day time-course experiment using immunohistochemistry. The expression of p65 was detected in the synovial lining layer and around the blood vessels in the inflamed synovium as early as Day 3 post-adjuvant injection. The cells that expressed p65 in the synovial lining were thought to be macrophage-like synoviocytes. The expression was stronger in the injected hindpaw than that in the noninjected hindpaw. Dexamethasone treatment at 1 mg/kg p.o. (Days 0-20) suppressed both the hindpaw edema and increase in p65 expression. Withdrawal of the treatment caused increases in both p65 expression and paw volume. Together these suggest that activated NF-kappa B was specifically expressed in the arthritic synovium and may play a significant role in the development of arthritis.

Animals↗
PubMed1997

Demyelination in severe combined immunodeficient mice by intracisternal injection of cerebrospinal fluid cells from patients with multiple sclerosis: neuropathological investigation.

Demyelinating lesions have been observed in severe combined immunodeficient (SCID) mice after intracisternal administration of cerebrospinal fluid cells (CSFC) from patients with multiple sclerosis (MS). Further investigation in our laboratory revealed that CSFC from 6 to 15 patients at exacerbation of MS caused demyelination. The factor leading to demyelination appears to be the high frequency of relapses during a short period, but not to the severity of the disease. Neuropathological and immunohistochemical studies revealed that a lack of inflammatory mononuclear cell infiltration within and around the demyelinating lesions or in leptomeninges was a common characteristic in all SCID mice with CSFC-induced demyelination. In affected mice killed 2-3 weeks after intracisternal administration of CSFC, foamy/vacuolar lesions with a small or moderate number of lipid-laden macrophages were seen in the white matter. Ultrastructurally, relative preservation of axons, in contrast to myelinoclastic features, as well as some remyelinated axons were observed. In affected SCID mice killed 4-6 weeks after intracisternal administration, more widespread foamy macrophages and necrotic foci with poor remyelination were seen. The findings were similar to those seen in experimental allergic encephalomyelitis, though without lymphocytic infiltration, but were quite different from the lesions observed in Theiler's murine encephalitis virus infection. The absence of an immunohistochemical reaction to the human leukocyte common antigen in the infiltrating mononuclear cells suggested that the graft-versus-host reaction was unlikely cause of the demyelinating lesions.

Adolescent↗
PubMed1997

A clinicopathological study of a patient with familial amyotrophic lateral sclerosis associated with a two base pair deletion in the copper/zinc superoxide dismutase (SOD1) gene.

The recognition of mutations in the copper/zinc superoxide dismutase (SOD1) gene in familial amyotrophic lateral sclerosis (FALS) has been a landmark in ALS research. We report a clinicopathological study of a female patient with FALS showing a two base pair deletion in exon 5 of the SOD1 gene. Her clinical course was rapid and she died 2 years after the onset. The SOD1 activity was down to 30% of the normal level. Western blot analysis did not reveal the mutant protein which was expected to be approximately 2.4 kDa smaller than normal SOD1 protein in molecular mass. In contrast to the neuropathological findings of the previously reported cases showing the same mutation, our case was characterized by sparing of the dorsal column and the presence of only a modest number of intracytoplasmic eosinophilic inclusions showing weak or partial immunoreaction for neurofilament and negative reaction for SOD1. Thus, the same mutation in the SOD1 gene does not necessarily induce consistent pathological changes in the central nervous system.

Adult↗
PubMed1997

Nitric oxide via an inducible isoform of nitric oxide synthase is a possible factor to eliminate inflammatory cells from the central nervous system of mice with experimental allergic encephalomyelitis.

We recently identified the inducible isoform of nitric oxide synthase (iNOS) in inflammatory lesions of the central nervous system (CNS) in mice with experimental allergic encephalomyelitis (EAE), a known animal model of multiple sclerosis (MS). In the present study, the role of excessive nitric oxide (NO) production via iNOS was investigated in mice with EAE using immunohistochemistry with antibodies to nitrotyrosine and iNOS, NADPH-diaphorase histochemistry, and the in situ terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) method to detect cell death, presumably through an apoptotic mechanism. NADPH-diaphorase histochemistry and immunohistochemistry for iNOS revealed an elevation of nitric oxide synthase (NOS) activity during the course of EAE, which came from iNOS. Nitrotyrosine was detected in infiltrated cells and some glial cells in the spinal cord lesions, where iNOS-positive inflammatory cells were present at the peak of EAE. The findings implied the generation of NO and peroxynitrite in the EAE lesions, which might damage structural and functional proteins. The TUNEL positive cells were mainly inflammatory ones, and most of them were located in close proximity to iNOS-positive cells, while some of them were iNOS-positive themselves. These results suggested that excessive NO via iNOS played an important role to eliminate inflammatory cells in the CNS of mice with EAE, possibly through an apoptotic mechanism.

Animals↗
PubMed1997

Role of nitric oxide in the convulsive seizures induced by fluoroquinolones coadministered with 4-biphenyl acetic acid.

1. Contribution of nitric oxide to the convulsive seizures induced by fluoroquinolones (FQs) coadministered with 4-biphenyl acetic acid (BPAA), the active metabolite of fenbufen, was assessed in mice. 2. Enoxacin + 4-biphenyl acetic acid caused clonic seizures in all treated mice, followed by tonic seizures and death. These events were associated with a significant increase in intracerebellar cyclic GMP. 3. Pretreatment with the nitric oxide synthase (NOS) inhibitor, NG-nitro-L-arginine methylester (L-NAME), but not with D-NAME, significantly reduced the incidence of convulsions and lethality, as well as the increase in cyclic GMP. 4. Pretreatment with N-methyl-D-aspartic acid (NMDA)-receptor antagonist, MK-801, inhibited only the transition of clonic seizure to tonic seizure without affecting the incidence of clonic seizure and lethality. 5. These findings suggest that FQs + BPAA exert convulsions by activating NOS partly through the mediation of the NMDA receptor in the brain cells.

Animals↗
PubMed1997

Immunolocalization of type I or type II activin receptors in the rat brain.

We have studied immunolocalization of activin receptors in the central nervous system using polyclonal antibodies (IgG) to type I (50-55 kDa, ActRI), type II (70-75 kDa, ActRII) or a subtype of type II known as type IIB (ActRIIB) receptors of activin. A total of 7 antisera to rat activin receptors was generated, i.e. 3 kinds of antisera to the extracellular domain (ActRI(81-89), ActRII(91-100), or ActRIIB(90-99)) and 4 antisera to the kinase domain (ActRI(323-333), ActRII(307-319), ActRII(407-420) or ActRIIB(306-319)). The region of aa 407-420 of ActRII is identical with that of ActRIIB. At first, we characterized these antibodies by Western blot analysis using ovarian proteins fractionated by preparative SDS-PAGE. All antibodies to ActRII and ActRIIB specifically reacted with 75 kDa-proteins which could also bind to activin-A. Anti-ActRII(91-100) antibody also reacted with 62 kDa-proteins which were capable of binding with activin-A. Although no positive reactions to anti-ActRI(81-89) antibody were seen in ovarian proteins, a positive reaction was detected at 52 kDa only when the proteins were deglycosylated. By use of these antibodies, immunolocalization of activin receptors was examined in the rat brain. The patterns of expression of activin type I and type II receptors were different. Positive reactions to anti-ActRII(91-100) antibody were detected in neurons of the cerebral cortex, hippocampus, medial amygdala and thalamus. In the hypothalamus, some neurons of the supraoptic nucleus were weakly stained, and widely scattered neurons of the lateral hypothalamic area were moderately stained. On the contrary, the most intense reactions to anti-ActRI(81-89) antibody were detected in neurons of the lateral hypothalamic area. In addition, many neurons of the cerebral cortex were also stained, but neurons of the hippocampus and the amygdala were not stained. These results suggest that activin may have physiological roles not only for hypothalamic neuroendocrinological and feeding-related systems as suggested previously but may also have functions in cortical and limbic pathways as a neuromodulator or for maintenance of neurons.

Activin Receptors↗
PubMed1997

Degeneration of the pyramidal tracts in patients with amyotrophic lateral sclerosis. A premortem and postmortem magnetic resonance imaging study.

To investigate focal hyperintensity in the internal capsule (IC) on magnetic resonance images (MRIs) and its clinical significance, 80 patients with amyotrophic lateral sclerosis (ALS) and 80 sex- and age-matched normal control subjects were studied. On T2-weighted images, hyperintense foci were found in the posterior part of the posterior limb (PL) of the IC in 41 (51%) of 80 control subjects. However, no subject showed increased signal intensities on proton density-weighted images. Hyperintense foci were also observed in the posterior part of the PL of the IC on T2-weighted images in 52 (65%) of 80 ALS patients and on proton density-weighted images in 26 (65%) of 40 ALS patients; the abnormally intense foci were seen at the same anatomical location in the IC as those in the normal control subjects. On postmortem MRI, the abnormally intense foci were found in the posterior part of the PL of the IC in the formalin-fixed brains from 9 ALS patients. Three normal control subjects did not show signal intensity changes on postmortem MRI. On histological examination of 9 ALS brains, distinct myelin pallor and gliosis were found in the posterior third of the PL of the IC. Proton density-weighted images appear to be useful to distinguish neuropathological changes in the corticospinal tract of ALS patients.

Adult↗
PubMed1997

Mitochondrial abnormalities in a murine model of primary carnitine deficiency. Systemic pathology and trial of replacement therapy.

Mitochondrial abnormalities and effectiveness of replacement therapy were examined in a murine model of systemic carnitine deficiency, namely the juvenile visceral steatosis (JVS) mouse. Homozygous JVS mice revealed severe lipid deposition and abnormal mitochondria in liver, heart, skeletal muscle, and kidney, but there was no pathological change in the nervous system, though they showed cerebral signs. There were numerous ragged-red fibers in muscles, but enzyme activities of the respiratory chain were intact. Histograms of oxidative and nonoxidative muscle fibers showed an increase in small and oxidative muscle fibers in 4-week-old JVS mice, but this difference no longer existed in 8-week- or 1-year-old JVS mice. On the contrary, Mn-superoxide dismutase immunostaining of muscle showed a focal increase in every age of JVS mice. With L-carnitine treatment, JVS mice could survive for a year, but to some extent, there were the same pathological changes as those seen in untreated mice.

Animals↗
PubMed1997

Quantitative RT-PCR for inhibin/activin subunits: measurements of rat hypothalamic and ovarian inhibin/activin subunit mRNAs during the estrous cycle.

Inhibins (alpha-beta(A) and alpha-beta(B)) and activins (beta(A)-beta(A), beta(A)-beta(B) and beta(B)-beta(B)) were originally isolated from ovarian follicular fluids as FSH secretion modifiers. Inhibin/activin subunits, alpha, beta(A) and beta(B), are widely distributed in several tissues, including gonads and brain, and inhibins and activins have been reported to be involved in ovarian or hypothalamic functions. In this study, we established and employed a competitive RT-PCR assay system for rat inhibin/activin subunits by capillary electrophoresis to determine rat hypothalamic and ovarian inhibin/activin subunit mRNA levels during the estrous cycle. Linearity of standards for alpha, beta(A), and beta(B) subunit assays were between 0.01-0.3 amol, 0.003-0.09 amol and 0.002-0.02 amol of each fragment DNA as a standard, respectively. Hypothalamic beta(A) subunit mRNA during the estrous morning (1000 h) tended to be increased compared with that of the proestrous evening (1700 h), although they were not significantly different. Ovarian alpha subunit mRNA levels tended to be increased during the proestrous morning (1000 h) and were significantly increased in the proestrous evening (1700 h), compared with diestrus and estrus (P < 0.05). Ovarian beta(A) subunit mRNA was also significantly higher in the proestrous evening, compared with diestrus and estrus (P < 0.05), but in the case of beta(B) subunit mRNA there was no difference among diestrus, proestrus and estrus. We thus established a sensitive competitive RT-PCR system for the measurement of inhibin/activin alpha, beta(A) and beta(B) subunits, and this assay system would be helpful for the study of inhibin/activin action in brain and other tissues where these factors are expressed at low levels.

Animals↗
PubMed1997

Chronic inflammatory demyelinating polyneuropathy accompanied by hepatocellular carcinoma.

We report a patient with chronic inflammatory demyelinating polyneuropathy (CIDP) accompanied by hepatocellular carcinoma (HCC). Due to the remarkable weakness in the lower limbs and loss of the position sense, he could not walk. On neurophysiological examination, he had impaired nerve conduction velocities. Biopsied nerve and muscle specimens demonstrated demyelination of nerve fibers and neurogenic degeneration of muscles. After steroid therapy he showed marked improvement in muscle strength and sensory function.

Anti-Inflammatory Agents↗
PubMed1996

The immunosuppressant leflunomide blocks the yeast Saccharomyces cerevisiae cell cycle at the G1 phase.

Leflunomide is a novel immunomodulatory drug representing a new small molecule class of substances which are structurally unrelated to previously described immunomodulatory/immunosuppressive compounds. The effect of leflunomide on the cell cycle of Saccharomyces cerevisiae was investigated to elucidate the molecular mechanism of its action in eukaryotic organisms. When yeast cells were treated with leflunomide, unbudded cells were accumulated, suggesting that leflunomide may arrest the cell cycle in the G1 phase. When leflunomide-treated cells were subjected to heat shock treatment, the cells became resistant to heat shock treatment, implying that leflunomide-mediated block to cell division results in entry from the proliferative cycle into the alternative developmental G0 phase.

Cell Cycle↗
PubMed1996

A quantitative method for the determination of plasmid copy number in recombinant yeast.

A method is described for the determination of plasmid copy number (PCN) in the recombinant yeast Saccharomyces cerevisiae producing human coagulation Factor XIII. Southern hybridization of restriction endonuclease HindIII-digested total DNA from yeast transformant with the 32P-labelled URA3 gene as a probe detected two band: one corresponding to the chromosomal URA3 gene and the other corresponding to the recombinant plasmid. Thus, the present method using the genomic URA3 gene as an internal standard allowed an estimation of both the plasmid and the standard simultaneously. Since haploid yeast cells harbour one copy of genomic URA3 gene, the PCN can be determined as the ratio of the amount of plasmid to that of genomic URA3 gene. A linear relationship between the determined PCN and the plasmid content was observed ranging from 0.3 to 200 ng. The method is reproducible and independent of the extraction efficiency for the recombinant plasmid. The present method was successfully used to analyzed the PCN of a centromere-based plasmid YCp50 (= 2.7) and of a 2 microns-based plasmid pEMBLyex4 (= 112).

DNA, Recombinant↗
PubMed1996

Therapeutic effect of secretin in patients with jaundice; double-blind placebo-controlled multicentric trial.

Secretin, a gastrointestinal hormone, has been shown to have a potent choleretic effect. Having already obtained some beneficial effects with secretin in patients with intrahepatic cholestasis, we sought to confirm its effects in a double-blind placebo-controlled study in patients with mild jaundice after acute or during chronic hepatitis, where total bilirubin level was in excess of 4.0 mg/dl for 3 days or more. Patients with primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), and familiar hyperbilirubinemia were excluded from the study. Ninety-three patients were included in this analysis, but the final evaluation covered 69 of them. No statistically significant differences were found in the reduction of serum bilirubin levels between secretin and placebo groups. As a number of patients with liver cirrhosis had been included, the subjects were subdivided into one group with cholestasis in hepatitis and one with liver cirrhosis. In the subgroup of cirrhotic patients who received secretin, serum levels of AST were significantly increased compared with the placebo group. However, since the choleretic effect of secretin is unique, further studies seem to be warranted.

Adolescent↗
PubMed1996

Chromosome spreading techniques for primary gastrointestinal tumors.

The requirement for well spread out chromosomes for the cytogenetic analysis of primary gastrointestinal tumors led us to develop new techniques. These techniques involved two main procedures: (1) preliminary incubation with culture medium in the presence of collagenase, Dispase, and colcemid, for 3 h, and (2) treatment with an extremely hypotonic solution (0.044M KCl) for 30 min. The techniques were applied to 11 gastrointestinal malignancies (including 1 early gastric cancer and 1 metastatic liver lesion of colon cancer) and significant increases (P < 0.01) in the number of metaphases of analyzable karyotypes were obtained, compared with a previous method in which the standard hypotonic molarity of KCL (0.075 M) was employed. The mean value for metaphase numbers of the analyzable karyotypes was 37.0 +/- 3.7% in the 5 gastric cancers and 44.7 +/- 4.8% in the 5 colon cancers and 1 metastatic lesion. These values were three times and more than twice, respectively, the values obtained by the previous method. A fluorescence in situ hybridization (FISH) study was carried out on one cologenic tumor, the alpha-satellite centromere-specific probe 17 being used. Deletion of the long arm of chromosome 17 was demonstrated. The method proposed here could yield a sufficient number of metaphases without the use of tissue culture that might cause alteration of karyotype. It can be employed with small biopsy specimens and in studies utilizing the FISH technique.

Aged↗
PubMed1996

Cation binding at the node of Ranvier in biopsied peripheral nerves of patients with Charcot-Marie-Tooth disease type 1A and hereditary neuropathy with liability to pressure palsies.

The node of Ranvier in myelinated fibers is known to have an affinity to bind cations. Demyelination and remyelination due to abnormal expression of a myelin protein may affect cation binding or vice versa under pathological conditions. To study the cation binding at the node of Ranvier in inherited demyelinating neuropathies associated with over- and under-expression of the peripheral myelin protein 22 (PMP-22), the reaction with ferric ion and ferrocyanide was used to visualize the cation binding sites in biopsied nerves of four patients with Charcot-Marie-Tooth disease type 1A (CMT1A) and two patients with hereditary neuropathy with liability to pressure palsies (HNPP), and the results were compared with those of four patients having acquired neuropathies with normal PMP-22 expression. In CMT1A, nodal widening or paranodal demyelination was associated with dense precipitates focally on both sides of the widened node. Although fainter precipitates were present at the node between remyelinated internodes, the percentage of nodes exhibiting the reaction product between normal and remyelinated internodes was not statistically different from that between normal internodes in CMT1A. In acquired neuropathies, on the other hand, the difference was significant between the two (P < 0.05), with reduction between normal and remyelinated internodes. At the nodes neighboring demylinated internodes, the percentage of nodes exhibiting the reaction product was reduced significantly in both CMT1A and acquired neuropathies, but to a lesser degree in CMT1A. Precipitates were clearly seen at the nodes neighboring a tomaculum in HNPP. The results suggest that preserved cation binding at the node may allow nerves to keep the electrical excitability in CMT1A and HNPP where myelin remodeling takes place at high frequency.

Adolescent↗