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Biomedical subjects

S Shoji

Publications and source records attributed to S Shoji.

At least 127 records · Page 7Linked to original sources

Blockage of N-myristoylation of HIV-1 gag induces the production of impotent progeny virus.

The role of the N-myristoylation of the human immunodeficiency virus type 1 (HIV-1) gag protein in ACH-2 cells was studied. The infectivity of HIV-1 from the cells stimulated with phorbol 12-myristate 13-acetate (PMA) was suppressed by pretreatment with N-myristoyl glycinal diethylacetal (N-Myr-GOA), a potent N-myristoylation inhibitor, and the blockage of myristoylation resulted in accumulation of immature gag precursors. The viral particles which budded from the non-N-Myr-GOA-treated ACH-2 cells stimulated with PMA exhibited a typical viral phenotype, whereas those which budded from the N-Myr-GOA-treated ACH-2 cells stimulated with PMA were twisted, as observed electron microscopically. In electron microscopic analyses with gold-labeled monoclonal antibodies to gag and env, gag and env were detected adjacent to each other in the PMA-stimulated ACH-2, but no env was detected in the cells treated with N-Myr-GOA. Taken together, the results suggest that the myristoylation of HIV-1 gag seems to be responsible for both maturation of gag and acquisition of HIV-1 infectivity.

Acetaldehyde↗

Characterization of amyloid beta protein species in cerebral amyloid angiopathy of a squirrel monkey by immunocytochemistry and enzyme-linked immunosorbent assay.

We analyzed the composition of amyloid beta protein (A beta) species in cerebral amyloid angiopathy (CAA) of an aged squirrel monkey. Immunocytochemistry demonstrated that the cerebral cortex contained no lesions other than widespread CAA with A beta40 as its apparent major component. However, enzyme-linked immunosorbent assay revealed that A beta42(43) predominated over A beta40 in a formic acid-extracted cortical fraction. These findings suggest possible underestimation of A beta42(43) levels in some previous immunocytochemical investigations.

Aging↗

Increased A beta 42(43)-plaque deposition in early-onset familial Alzheimer's disease brains with the deletion of exon 9 and the missense point mutation (H163R) in the PS-1 gene.

Cerebral amyloid deposition is a neuropathological hallmark for Alzheimer's disease (AD). Immunohistochemical analysis of two A beta species (A beta 42/43 and A beta 40) deposition was undertaken using the carboxyl end-specific antibodies to determine the molecular alteration of these species in the brains of patients whose presenilin 1 (PS-1) gene, the major causative gene for the early-onset familial AD, bears the point mutation (H163R) and the deletion of exon 9. We found a marked increase in A beta 42-plaque deposition in brains of patients with PS-1 mutations compared with that in brains of those with sporadic AD. The results of immunohistochemical analysis indicate that both mutation and deletion in the PS-1 gene promote deposition of A beta 42-plaques indicating the pathological association of PS-1 and betaAPP/A beta 42 in early-onset familial AD.

Alzheimer Disease↗

Amyloid beta protein 42(43) in cerebrospinal fluid of patients with Alzheimer's disease.

To investigate the pathomechanism of amyloid beta protein (A beta) deposition in brains with Alzheimer's disease (AD), cerebrospinal fluid (CSF) levels of A beta species (CSF-A beta) with different carboxy termini, i.e. A betaX-40 and A betaX-42(43) as well as A beta1-40 and A beta1-42(43), were measured in patients with AD and age-matched controls without dementia (CTR) using sandwich enzyme-linked immunosorbent assays (ELISAs). The present study revealed that both CSF-A betaX-42(43) and A beta1-42(43) levels were significantly lower in the AD patients (P<0.005) than in the CTR group, whereas neither CSF-A betaX-40 nor CSF-A beta1-40 levels showed any differences between the two groups. In addition, although there was no difference between the ratios of A betaX-40 to A beta1-40 in the AD and CTR groups, the ratios of A betaX-42(43) to A beta1-42(43) were increased in the AD group compared with those in the CTR group (P<0.05). Therefore, it can be assumed that the ratios of amino terminal truncations and/or modifications of CSF-A beta42(43) with carboxy termini ending at residue 42(43) were more increased in the AD group than in the CTR group. Increased adsorption of A beta42(43) to A beta deposition in AD brains, decreased secretion of A beta42(43) to CSF and/or increased clearance of A beta42(43) from CSF might explain the diminished levels of A beta42(43) in the CSF of AD patients. In addition, CSF-A beta42(43) could reflect increased amino terminal truncations and/or modifications of A beta42(43) in AD brains.

Aged↗

Abeta1-40 but not Abeta1-42 levels in cortex correlate with apolipoprotein E epsilon4 allele dosage in sporadic Alzheimer's disease.

Apolipoprotein E (ApoE) epsilon4 allele is established to be a risk factor for the development of late-onset Alzheimer's disease (AD) which is associated with increased frequency of senile plaques and extent of amyloid angiopathy. In a recent report, we demonstrated that ApoE epsilon4 dosage correlates with an increase in A beta1-40 but not A beta1-42/43-immunoreactive plaques. In the present study, we sought to confirm this relationship at a biochemical level by using a sensitive ELISA to measure the amounts of A beta1-42/43 and A beta1-40 in cerebral cortex in 36 cases of sporadic AD. We found that dosage of ApoE epsilon4 allele correlated significantly with cortical A beta1-40 levels, while levels of A beta1-42 showed no significant association with genotype. These results parallel our immunohistochemical findings and suggest that A beta1-40 may play a key role in the pathogenesis of late-onset sporadic AD.

Aged↗

Eotaxin is a potent chemotaxin for human basophils.

We studied the effect of eotaxin, a novel eosinophil-active CC chemokine with high target cell specificity, on human basophils. Eotaxin induced higher levels of chemotactic response with a lower ED50 compared with RANTES in basophils; half-maximal migration occurred at a concentration of approximately 3 nM. On the other hand, it exerted only a marginal effect on either histamine release or leukotriene C4 generation. In addition, nested PCR amplification experiments revealed the expression of CC CKR3, a putative receptor for eotaxin, on basophils. Since accumulation of both basophils and eosinophils is an important aspect of allergic inflammation, eotaxin potentially plays a pathogenic role in allergic disorders by inducing migration of both of these cell types.

Basophils↗

Inhibitory action of (-)-epigallocatechin gallate on radiation-induced mouse oncogenic transformation.

The anticarcinogenic activity of a major component of green tea, (-) epigallocatechin gallate (EGCg) was examined by using the radiation-induced oncogenic transformation in C3H10T1/2 cells. EGCg substantially suppressed the radiation-induced transformation so that the transformation frequency with 15 microM of EGCg was reduced nearly to spontaneous levels. This effect of EGCg was in a dose-dependent manner and significant suppression of transformation was observed even in treatment of cells with 5 microM of EGCg concentration where the cytotoxicity was mild. The inhibitory effect of EGCg was maximal when it was present during the entire incubation period. However, neither treatment prior to nor concurrent with radiation was effective, suggesting that EGCg action is mainly involved in the promotional stage of C3H10T1/2 cell transformation.

Animals↗

Plasma levels of amyloid beta proteins Abeta1-40 and Abeta1-42(43) are elevated in Down's syndrome.

To investigate the effect of the overexpression of beta-amyloid precursor protein (APP) on the production of two major amyloid beta protein (Abeta) species, Abeta40 and Abeta42(43), we measured amounts of Abeta1-40 and Abeta1-42(43) in the plasma from 44 patients with Down's syndrome (DS) (age, 19-61 years) and 66 age-matched normal controls using enzyme-linked immunosorbent assays. Plasma concentrations of both Abeta1-40 and Abeta1-42(43) were increased about 3-fold and 2-fold, respectively, in DS patients compared with normal controls. Especially, the increases in plasma Abeta1-40 in DS patients were statistically higher than the 1.5-fold increase one might predict based on the gene dose of APP in DS. These findings showed that both Abeta1-40 and Abeta1-42(43) are increased in plasma in DS patients, the former more than the latter, suggesting that overexpression of APP and/or other genes may have different effects on the production of these two Abeta species in DS.

Adult↗

Hydrocephalus in the Otx2+/- mutant mouse.

Mice with the Otx2+/- mutation often die during the postneonatal period. Before death these animals, generated from TT2 ES cells and crossed with CBA mice, develop a dome-shaped head, weakness of the limbs, kyphosis, lethargy, drowsiness, and emaciation. Autopsy of these mice revealed eminent dilatation of lateral ventricles and a ballooned cerebrum. Histological analysis shows edematous change of the periventricular white matter. These results suggest that Otx2 functions as a head organizer, and a mutation of this gene is a likely cause of hydrocephalus in mammals. Additionally, craniobasal skeletal anomaly in half of the heterozygotes and dwarfism in some of the female heterozygotes are described.

Abnormalities, Multiple↗

Deposition of amyloid beta protein (A beta) subtypes [A beta 40 and A beta 42(43)] in canine senile plaques and cerebral amyloid angiopathy.

To clarify the immunohistochemical features of canine senile plaques (SPs) and cerebral amyloid angiopathy (CAA), the distribution of the amyloid beta protein (A beta) subtypes A beta 40 and A beta 42(43), A beta precursor protein (APP), and glial cell reaction were examined in the brains of seven aged dogs (12-18 years). A beta 42(43) was found to be deposited in all types of SPs, whereas A beta 40 was deposited only in mature (classical and primitive) plaques. CAA, which was located along parenchymal and meningeal arterioles and capillaries, consisted of both subtypes of A beta. APP was exhibited in normal and degenerative neurons and swollen neurites of mature plaques. It was, therefore, considered that A beta 42(43) in diffuse plaques might be derived from APP in neurons, while A beta 40 and A beta 42(43) in mature plaques might be generated from APP in swollen neurites in the plaque. In contrast to the case in humans, in whom deposition of A beta 40 and A beta 42(43) in the mature plaques is predominantly associated with microglial reaction, in dogs we found that it was closely associated with astroglial reaction. The present findings showed characteristics of canine SPs which are different from those of humans.

Aging↗

Histological determination of nitric oxide synthase (NOS) and NADPH-diaphorase in ragged-red fibers from patients with mitochondrial encephalomyopathies.

To determine localization of nitric oxide synthase in diseased muscle, we performed immunohistochemical analyses of neuronal-type nitric oxide synthase (nNOS) and endothelial-type nitric oxide synthase (ec-NOS) in biopsied muscles from five patients with mitochondrial encephalomyopathies. Immunostaining of nNOS was prominent in the sarcolemmal region of the ragged-red fibers, and weak in the sarcolemmal region of normal fibers. Immunostaining of ec-NOS was strongly positive in the myofibrils of ragged-red fibers. Ec-NOS immunoreactivity corresponded to fibers positive for SDH by histochemistry. Histochemical methods revealed prominent staining for NADPH-diaphorase on surface membranes of the ragged-red fibers. Findings suggest that nitric oxide is important in the muscles of patients with mitochondrial encephalomyopathies.

Adult↗

Increased levels of nitric oxide derivatives in induced sputum in patients with asthma.

BACKGROUND: Nitric oxide (NO) plays an important role as an inflammatory mediator in the airways. However, because direct measurement of endogenous NO has been difficult in vivo, the exact pathologic roles of NO in human airway inflammation have remained unclear. OBJECTIVE: This study was designed to determine whether NO may be harmful by amplifying allergic inflammation in asthmatic airways. METHODS: In this study we examined the concentration of stable end products of NO, nitrite and nitrate, in induced sputum in 18 patients with asthma and 10 normal control subjects and evaluated the relationship between levels of NO derivatives in sputum and cellular and biochemical profiles, the degree of airflow obstruction, and the cytotoxic activities for epithelial cells. RESULTS: The concentration of NO derivatives in induced sputum was significantly higher in patients with asthma than in normal control subjects (1086 +/- 325 mumol/L, 577 +/- 115 mumol/L; p < 0.05). Percentages of eosinophil counts and eosinophil cationic protein levels in sputum were also significantly higher in patients with asthma. Moreover, percentages of eosinophil counts and eosinophil cationic protein levels in sputum in patients with asthma were significantly correlated with the concentration of NO derivatives in sputum (r = 0.63, p < 0.01; r = 0.56, p < 0.05, respectively). In addition, we found that the concentration of NO derivatives in sputum in patients with asthma was significantly correlated with the degree of airflow obstruction (FEV1/forced vital capacity) (r = -0.62, p < 0.01) and with percentages of shedding epithelial cells (r = 0.61, p < 0.01). CONCLUSION: We have shown that a higher concentration of NO derivatives was found in induced sputum of patients with asthma as compared with normal subjects. The clinical implication of our findings is that measurement of NO derivatives in induced sputum may be useful for assessing allergic inflammation in airways.

Adult↗

ICE/CED-3 family executes oligodendrocyte apoptosis by tumor necrosis factor.

Tumor necrosis factor (TNF) is thought to be one of the mediators responsible for the damage of oligodendrocytes (OLGs) in multiple sclerosis (MS). We report here the involvement of the interleukin 1beta-converting enzyme (ICE)/Caenorhabditis elegans gene ced-3 (CED-3) family in TNF-mediated cell death of OLGs. The addition of TNF-alpha to primary cultures of OLGs that express ice and cpp32 significantly decreased the number of live OLGs in 72 h. DNA fragmentation was detected in TNF-treated OLGs at 36 h with the terminal deoxynucleotidyl transferase dUTP nick end-labeling assay. Benzyloxycarbonyl-Asp-CH2OC(O)-2,6-dichlorobenzene, an inhibitor of the ICE/CED-3 family that shows p35-like inhibitory specificity, protected against the TNF-induced cell death of OLGs. Furthermore, acetyl-YVAD-CHO (a specific inhibitor of ICE-like proteases) as well as acetyl-DEVD-CHO (a specific inhibitor of CPP32-like proteases) enhanced the survival of OLGs treated with TNF-alpha, indicating that ICE- and the CPP32-mediated cell death pathways are activated in TNF-induced OLG cell death. Our results suggest that the inhibition of ICE/CED-3 proteases may be a novel approach to treat neurodegenerative diseases such as MS.

Animals↗

Japanese families with autosomal dominant pure cerebellar ataxia map to chromosome 19p13.1-p13.2 and are strongly associated with mild CAG expansions in the spinocerebellar ataxia type 6 gene in chromosome 19p13.1.

Autosomal dominant cerebellar ataxia is a group of clinically and genetically heterogeneous disorders. We carried out genomewide linkage analysis in 15 families with autosomal dominant pure cerebellar ataxia (ADPCA). Evidence for linkage to chromosome 19p markers was found in nine families, and combined multipoint analysis refined the candidate region to a 13.3-cM interval in 19p13.1-p13.2. The remaining six families were excluded for this region. Analysis of CAG-repeat expansion in the alpha1A-voltage-dependent calcium channel (CACNL1A4) gene lying in 19p13.1, recently identified among 8 small American kindreds with ADPCA (spinocerebellar ataxia type 6 [SCA6]), revealed that 8 of the 15 families studied had similar, very small expansion in this gene: all affected individuals had larger alleles (range of CAG repeats 21-25), compared with alleles observed in neurologically normal Japanese (range 5-20 repeats). Inverse correlation between the CAG-repeat number and the age at onset was found in affected individuals with expansion. The number of CAG repeats in expanded chromosomes was completely stable within each family, which was consistent with the fact that anticipation was not statistically proved in the SCA6 families that we studied. We conclude that more than half of Japanese cases of ADPCA map to 19p13.1-p13.2 and are strongly associated with the mild CAG expansion in the SCA6/CACNL1A4 gene.

Adult↗

Circulating promyelocytes and low levels of CD16 expression on polymorphonuclear leukocytes accompany early-onset periodontitis.

Early-onset periodontitis (EOP) is characterized by rapidly progressive alveolar bone loss, chemotactic defects of neutrophils, and significant familial aggregation. We found immature myeloid lineage cells, defined as promyelocytes, in the peripheral blood in patients with EOP. A hematological examination of peripheral blood cells showed normal reference values regarding cell proportions. Flow cytometry revealed significantly lower expression of CD16, a glycosylphosphatidylinositol (GPI)-anchored protein, on peripheral neutrophils in patients compared with those in age- and sex-matched healthy controls, whereas the levels of CD11a and CD11b expression were similar. The chemotactic response of neutrophils was lower toward not only formyl-methionyl-leucyl-phenylalanine but also complement fragment C5a than that of healthy controls. The expression of another GPI-anchored protein, CD14, was equally expressed by controls and patients. Therefore, the low level of CD16 expression was not due to the incomplete synthesis of the GPI anchor. GPI anchors of CD16 on neutrophils from controls and patients were both partially resistant to phosphatidylinositol-specific phospholipase C. The presence of promyelocytes in peripheral blood, low expression of CD16, and low chemotactic response of neutrophils suggest that patients with EOP have an abnormal maturation system in myeloid lineage cells in the bone marrow, which may be associated with the onset and course of EOP.

Adult↗

PAMP is a novel inhibitor of the tachykinin release in the airway of guinea pigs.

Proadrenomedullin NH2-terminal 20 peptide (PAMP), a newly identified hypotensive peptide, may play physiological roles in airway and cardiovascular controls. This study was designed to determine the mechanism responsible for the bronchoprotective effects of PAMP on capsaicin-induced bron-choconstriction in anesthetized guinea pigs. PAMP (10(-8)-10(-6) M) significantly inhibited capsaicin-induced bronchoconstriction in a dose-dependent manner. The bronchoprotective effect of PAMP (10(-6) M) was as large as that of isoproterenol (10(-7) M) and lasted > 10 min. The concentration of immunoreactive substance P (SP) in bronchoalveolar lavage fluid after administration of capsaicin (4 x 10(-6) M) was 120 +/- 10 fmol/ml. PAMP significantly inhibited the release of immunoreactive SP in a dose-dependent manner (60 +/- 6 fmol/ml for (10(-6) M PAMP, P < 0.01; 84 +/- 6 fmol/ml for 10(-7) M PAMP, P < 0.01; and 95 +/- 6 fmol/ml for 10(-8) M PAMP, P < 0.05). PAMP (10(-6) M) did not significantly affect exogenous neurokinin A (NKA) or NKA + SP-induced bronchoconstriction, whereas isoproterenol (10(-7) M) significantly inhibited exogenous tachykinin-induced bronchoconstriction. These findings suggest that the bronchoprotective effects of PAMP are mainly due to inhibition of the release of tachykinins at airway C-fiber endings.

Adrenomedullin↗

Adenosine modulates endothelin-induced bronchoconstriction in guinea pig airway.

The present study was designed to determine whether endogenous and exogenous adenosine modulates endothelin (ET)-induced bronchoconstriction. Exogenous adenosine enhances ET-induced bronchoconstriction. Following pretreatment with adenosine deaminase and theophylline to eliminate or antagonize endogenous adenosine, ET-1-induced bronchoconstriction was significantly attenuated, but not that of ET-3. In conclusion, this is the first report of an enhancement of ET-induced bronchoconstriction of guinea pig airways by endogenous and exogenous adenosine. Our findings may be useful in designing specific adenosine receptor antagonists as therapeutic agents in the management of bronchial asthma.

Acetylcholine↗