Search PubMed⌕ Search

Biomedical subjects

T Iwaki

Publications and source records attributed to T Iwaki.

At least 145 records · Page 8Linked to original sources
PubMed1995

Neurodegeneration in the limbic and paralimbic system in progressive supranuclear palsy.

Progressive supranuclear palsy is neuropathologically characterized by neuronal degeneration of the basal ganglia, brain stem, and cerebellum. In addition, cortical neuronal degeneration associated with neurofibrillary tangles formation has been identified over wide areas of the brain in patients with progressive supranuclear palsy. We studied the distribution of alpha B-crystallin-positive degenerating neurons in cases with progressive supranuclear palsy, and compared them with those in Pick's disease. Alzheimer's disease, senile dementia of Alzheimer type, and normal aged individuals. A large number of alpha B-crystallin-positive neurons was found in the cerebral cortices of four out of nine patients with progressive supranuclear palsy. In particular, alpha B-crystallin-positive ballooned neurons were frequently observed in deep cortical pyramidal cell layers of the limbic and paralimbic systems in these diseases. The involvement of the limbic and paralimbic systems may thus contribute to personality changes as well as to memory and cognitive impairment in some patients with progressive supranuclear palsy.

Aged↗
PubMed1995

Proliferative activity and apoptosis of Langerhans histiocytes in eosinophilic granulomas as evaluated by MIB-1 and TUNEL methods.

Aims-To identify the role played by apoptosis in tumour regression.Methods-The growth fraction and apoptotic cell loss of four cases of eosinophilic granuloma were investigated using monoclonal antibodies against Ki-67 proliferation marker (MIB-1) antigen and the TdT mediated dUTP-biotin 3'-OH nick end labelling (TUNEL) method. These data were then compared with the clinical growth rate.Results-Only the Langerhans histiocytic cells, which reacted positively with anti-S-100 protein antibody, were immunolabelled with antibodies to proliferating cell nuclear antigen and Ki-67 antigen (MIB-1). Many apoptotic figures of histiocytic cells were also detected in all cases by the TUNEL method. In a patient whose tumour clinically showed spontaneous regression, the TUNEL staining index gave a higher score than the MIB-1 staining index.Conclusions-The main cause of the spontaneous regression of the tumours was postulated to be programmed cell death (apoptosis).

Journal Article↗
PubMed1995

Purification and characterization of phosphoribulokinase from the cyanobacterium Synechococcus PCC7942.

Phosphoribulokinase (PRK) was purified to electrophoretic homogeneity from Synechococcus PCC7942 with high specific activity. Molecular masses of the native enzyme and its subunit were 178 and 42 kDa, respectively. Cys-17 and Cys-38 were conserved in the cyanobacterial PRK, but 18 amino acid residues between them were missing among the 40 residues found in higher plant PRKs.

Amino Acid Sequence↗
PubMed1994

MIB1 staining index and scoring of histologic features in meningioma. Indicators for the prediction of biologic potential and postoperative management.

BACKGROUND: The biology of brain tumors, including cell kinetics, has been studied. Recently, monoclonal antibody to Ki67 (MIB1), a nuclear protein related to cell proliferation, has been analyzed immunohistochemically using tissue prepared from paraffin embedded sections. METHODS: The authors assessed the prognostic usefulness of various histologic indicators of the biologic potential of meningiomas in patients who underwent total resection (Simpson's Grade I and II) by evaluating the time to recurrence as an end point. Forty-three patients with a total of 36 meningiomas and 7 hemangiopericytomas were investigated by immunohistochemical analysis using MIB1. RESULTS: MIB1 staining index (SI) and histologic score were well correlated with the recurrence-free interval (r = -0.6749, P = 0.002 and r = -0.4939, P = 0.027, respectively) and with each other (r = 0.7909, P < 0.001). The MIB1 SI and histologic score in the nonrecurrence group were significantly lower than those in the recurrence/metastasis group (P < 0.001 and P = 0.001, respectively). The values of these indicators showed that as the value increased, so did the recurrence rate. CONCLUSIONS: Evaluation using the MIB1 SI and total histologic score of meningioma is useful in assessing the prognosis as well as postoperative management of these patients.

Adolescent↗
PubMed1994

Detection of human T lymphotrophic virus type I (HTLV-I) proviral DNA and analysis of T cell receptor V beta CDR3 sequences in spinal cord lesions of HTLV-I-associated myelopathy/tropical spastic paraparesis.

Identification of the localization of human T lymphotrophic virus type I (HTLV-I) proviral DNA in the central nervous system (CNS) is crucial to the understanding of the pathogenesis of HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) pathogenesis. We have developed a sensitive detection method, called two-step polymerase chain reaction (PCR) in situ hybridization, which enabled us to detect the HTLV-I proviral DNA in paraffin-embedded spinal cord tissue sections from HAM/TSP patients. HTLV-I proviral DNA was detected only in the nucleus of lymphocytes that had infiltrated into the spinal cord. However, no proviral DNA was amplified in any neuronal cells, including neurons and glial cells. This indicates that the demyelination of the spinal cord by HTLV-I as a result of viral infection of oligodendrocytes or neuronal cells is unlikely. The T cell receptor V beta gene sequence from lymphocytes in the spinal cord lesions taken from the same HAM/TSP autopsy cases revealed unique and restricted CDR3 motifs, CASSLXG(G) (one-letter amino acid. X is any amino acid), CASSPT(G), and CASSGRL which are similar to those described in T cells from brain lesions of multiple sclerosis (MS) and in a rat T cell clone derived from experimental allergic encephalomyelitis (EAE) lesions. The present results suggest that T cells containing restricted V beta CDR3 motifs, which are also found in MS and EAE, become activated upon HTLV-I infection and infiltrate into the spinal cord lesions of HAM/TSP patients.

Adult↗
PubMed1994

Adrenoleukodystrophy gene encodes an 80 kDa membrane protein.

An antibody against the synthetic C-terminal peptides deduced from the cDNA of the gene responsible for X-linked adrenoleukodystrophy (ALD) was produced to characterize the product of the ALD gene. The antibody reacted with the 80 kDa band protein in control fibroblasts, while no bands were detected in the fibroblasts from a patient with ALD (#163), in which mRNA of the ALD gene was undetectable based on Northern blot analysis. The 293T cells transfected with the full-coding cDNA inserted in the expression vector produced a new 80 kDa protein, as detected by Western blot. In an immunocytological study, the staining was in a punctate pattern, in the normal fibroblasts. However, there was no punctate staining in the #163 cells. These data thus indicate that the ALD gene encodes an 80 kDa membrane protein.

Adrenoleukodystrophy↗
PubMed1994

Expression of the alpha 2-macroglobulin-encoding gene in rat brain and cultured astrocytes.

The alpha 2-macroglobulin (alpha 2M), a protease inhibitor, is a major acute-phase protein in rats, and is produced in the liver during acute inflammation. Recently, it has been demonstrated that alpha 2M is also produced by cultured astrocytes from newborn rat brain and has neurite-promoting activity. Here, we found that the expression of the alpha 2M gene was significantly enhanced in the brain following intraperitoneal injection of the neurotoxicant, kainic acid (KA), suggesting that alpha 2M acts as an acute-phase protein in the brain, as in the case of the liver, and may be involved in neural repair processes. Expression of alpha 2M in cultured astrocytes was shown to be stimulated by interleukin-6 (IL-6) and/or leukemia inhibitory factor (LIF) in the presence of glucocorticoid. The amount of mRNAs for IL-6 and LIF increased in the brain of KA-injected rats prior to alpha 2M induction. These results strongly suggested that IL-6 and LIF are involved in alpha 2M induction in the brain, as in the case of the liver. Analysis of the cis-acting element(s) and the trans-acting factor(s) suggested that the regulatory mechanism for alpha 2M expression in astrocytes was similar to that in inflamed liver.

Animals↗
PubMed1994

IHF supresses the inhibitory effect of H-NS on HU function in the hin inversion system.

In the hin-mediated DNA inversion system, HU facilitates formation of the synaptic complex composed of two recombination sites spaced 996 bp apart and of the enhancer situated between them, by looping the DNA as to promote interaction of Hin invertase with the Fis enhancer factor [Johnson et al., Nature 329 (1987) 462-465]. The HU requirement for the in vivo hin-mediated inversion was demonstrated previously [Wada et al., Gene 76 (1989) 345-352; Hillyard et al., J. Bacteriol. 172 (1990) 5402-5407; Haykinson and Johnson, EMBO J. 12 (1993) 2503-2512] and in the current experiments. This HU action, however, required IHF when H-NS was present in the cell; i.e., the inversion reaction of the hin-invertible DNA fragment carried by the pKK1202R plasmid proceeded efficiently in host cells either deficient in H-NS or in the presence of both H-NS and IHF, but not in the cells depleted for IHF alone. The level of hin mRNA in mutant cells lacking HU or IHF, in which hin inversion did not occur, was normal or slightly increased. When IHF was absent, the stimulating effect of HU on in vitro DNA circle formation of a 125-bp hin fragment between hixL and the enhancer where Fis binds was inhibited by H-NS. The present study provides an example of a multi-component interaction between HU, H-NS and IHF on the hin DNA region, which contains three characteristic sites, a d(A/T)4 stretch and bent DNA site, and two putative IHF-binding sites.

Bacterial Outer Membrane Proteins↗
PubMed1994

Cytoplasmic inclusions of astrocytic elements of glial tumors: special reference to round granulated body and eosinophilic hyaline droplets.

Round granulated body (RGB) and eosinophilic hyaline droplets (EHDs) have been described as cytoplasmic inclusions of certain astrocytic tumors. In the previous literature, however, these inclusions have been described using various terms or regarded as nosologically the same entity. Light microscopically, RGB appeared as a round discrete body filled with fine uniform granules, while EHDs demonstrated a cluster of bright eosinophilic, round objects of various size. They could be clearly distinguished even by conventional histochemical staining such as the Masson trichrome stain and the phosphotungstic acid hematoxylin preparation. Both RGB and EHDs expressed positive immunoreactions for glial fibrillary acidic protein, several lysosomal markers, and some stress-response proteins. The ultrastructural appearances of these inclusions were distinct, however, one common feature was that they consisted of aggregations of numerous membrane-bound electron-dense bodies. Thus, both inclusions appear to be produced by neoplastic astrocytes and are possibly related to the lysosomal system. We examined the presence of RGB and EHDs in 138 astrocytic tumors. Both inclusions occurred most frequently in pleomorphic xanthoastrocytomas, followed by gangliogliomas and pilocytic astrocytomas. Subependymal giant cell astrocytomas exhibited only RGBs. RGBs and EHDs were not seen in any abundance in glioblastomas, gliosarcomas, fibrillary astrocytomas, protoplasmic astrocytomas, or oligo-astrocytomas. Some glioblastomas, however, showed only EHDs in small numbers. Several anaplastic astrocytomas were associated with a large number of RGBs and/or EHDs, and they revealed only rare mitosis despite marked cellular pleomorphism. Although RGB and EHDs have different morphological features, the presence of these inclusions in abundance may represent either a degenerative change, a long-standing lesion, or an indolent growth of the astrocytic tumors.

Adolescent↗
PubMed1994

Sense and antisense modification of glial alpha B-crystallin production results in alterations of stress fiber formation and thermoresistance.

The phenotypic effects of selectively altering the levels of alpha B-crystallin in cultured glial cells were analyzed using sense and antisense approaches. Rat C6 glioma cells and human U-373MG glioma cells were transfected with a rat alpha B-crystallin sense cDNA or an antisense cDNA regulated by a Rous sarcoma virus promoter to alter cellular levels of alpha B-crystallin. The antisense strategy resulted in decreased alpha B-crystallin levels, as revealed by Western blot and immunocytochemical analyses. The reduced alpha B-crystallin expression was accompanied by alterations in cellular phenotype: (a) a reduction of cell size and/or a slender cell morphology; (b) a disorganized microfilament network; and (c) a reduction of cell adhesiveness. Like HSP27, the presence of additional alpha B-crystallin protein confers a thermoresistant phenotype to stable transfectants. Thus, alpha B-crystallin in glioma cells plays a role in their thermal resistance and may contribute to the stability of cytoskeletal organization.

Animals↗
PubMed1994

An exon 8-spliced out transcript of neurofibromatosis 2 gene is constitutively expressed in various human tissues.

We succeeded in cloning the exon 8-spliced out transcript of neurofibromatosis 2 (NF2) gene in human glioma cell lines. We then investigated the expression of the spliced out form in various human tissues by PCR analysis followed by Southern blot hybridization and sequencing to evaluate whether it was generated by normal alternative splicing or by a splicing mutation. The analysis revealed the splicing out of exon 8 in the various tissues, and the transcript missing exon 8 should thus be considered as a product of normal alternative splicing. Our results further support the possibility that the NF2 gene expresses multiple alternatively-spliced transcripts variantly in different tissue types.

Base Sequence↗
PubMed1994

Infectivities of four isolates of Taenia taeniaeformis to various rodents.

Taenia taeniaeformis were isolated from Norway rats captured at Sapporo (SRN isolate) and Kuala Lumpur, Malaysia (KRN) and from Bedford's gray red-backed voles at Toubetsu (TCR) and Abuta (ACR). SRN, KRN and TCR isolates showed similar degree of infectivity to various rodents in which cysticerci with hooks were obtained in laboratory rats, white tuberous lesions in mice and no cysts or lesions in Mongolian gerbils and voles. Contrary to this, inoculation with ACR isolate eggs resulted in strobilocerci formation in the liver of voles, but no cysts were observed in rats, mice or gerbils. This host specificity of ACR isolate to voles suggests that it might be a new species of Taenia.

Animals↗
PubMed1994

An immunohistochemical study of tissue transglutaminase in gliomas with reference to their cell dying processes.

Tissue transglutaminase is a Ca(2+)-dependent enzyme that catalyzes the formation of protein cross-links by an acyl transfer reaction. Recent reports have suggested that tissue transglutaminase is induced by tumor progression and apoptosis. In this study we immunohistochemically investigated a series of gliomas by using an antiserum against a dodecapeptide from the COOH-terminal of tissue transglutaminase. Among the gliomas the presence of positive immunoreactivity tended to increase in malignant counterparts. It is also noteworthy to mention that glioblastoma cells surrounding the zonal necrosis in a palisade fashion were strongly immunolabeled. The degenerating products in tumor cells, such as round granulated bodies, were primarily immunopositive, whereas Rosenthal fibers were negative. Dying cells through apoptosis in the metastatic brain tumors could be easily recognized by the presence of tissue transglutaminase. In conclusion, tissue transglutaminase may therefore be valuable in the prognostic characterization of gliomas with respect to the detection of dying cells. However, the appearance of tissue transglutaminase-positive neoplastic cells was not limited to apoptotic bodies but could also be detected in necrobiotic cell nests.

Amino Acid Sequence↗
PubMed1994

Developmental and morphological characteristics of Taenia taeniaeformis (Batsch, 1786) in Clethrionomys rufocanus bedfordiae and Rattus norvegicus from different geographical locations.

Developmental and morphological characteristics of 3 isolates of Taenia taeniaeformis isolated from Clethrionomys rufocanus bedfordiae in Abuta (70 km southwest of Sapporo), Japan (isolate ACR), and from Rattus norvegicus in Sapporo, Japan (isolate SRN) and Kuala Lumpur, Malaysia (isolate KRN) were compared. Eggs of 3 isolates were administered to several species of rodents. Isolate ACR infected C. rufocanus bedfordiae, Apodemus speciosus, and Apodemus argenteus, but not rats or mice, whereas isolate SRN and isolate KRN were infective to rats, mice, A. speciosus, and A. argenteus, but not to C. rufocanus bedfordiae. The increase in cyst size of isolate ACR continued during the experimental period, whereas that of the other 2 isolates had ceased growing after 30 days postinfection. However, significant differences were observed in the length of the small rostellar hooks, number and distribution of testes, and the length of the cirrus sac between isolate ACR and the other 2 isolates. Thus it is suggested that isolate ACR is a distinct strain or even a new species.

Animals↗
PubMed1993

Immunohistochemical distribution of amyloid precursor protein during normal rat development.

This study focused on the immunohistochemical identification of the beta/A4 amyloid precursor protein (APP) in various developmental stages of both the rat central nervous system (CNS) and the peripheral nervous system (PNS). A comparative study with myelin basic protein (MBP) and synaptophysin (SYP) facilitated the understanding of neuronal maturation and synaptogenesis on both prenatal and postnatal development. Our immunohistochemical study revealed APP to be widely distributed through the nervous system while existing mainly in the cytoplasm, dendrites and axons of the neurons. However, immunoreactivity was also observed in either the ependymal cells or the choroid plexus epithelial cells. Our immunostaining was carried out by the hydrated autoclaving method and revealed the expression of APP at embryonic day 15 in the neuron of the mesencephalic nucleus of the trigeminal nerve and the anterior horn of the spinal cord, trigeminal and spinal ganglion, ependymal cells and the choroid plexus. We thus observed dramatic changes of APP expression in the cerebellum from the embryonic stage. The maturation of synaptogenesis in the cerebellar molecular layer was parallel to the extension of the dendrites of Purkinje cells, which revealed immunoreactivity for APP. These findings suggested that APP played an important role in neuronal maturation and synaptogenesis. Thus, APP is considered to be a useful marker for neuronal development.

Amyloid beta-Protein Precursor↗
PubMed1993

Antibodies for fluorescent molecular rotors.

We have prepared monoclonal antibodies for the fluorescent molecular rotors 9-(2-carboxy-2-cyanovinyl)julolidine (CCVJ) and 9-(dicyanovinyl)julolidine (DCVJ). Mouse monoclonal antibody (IgG2b) prepared against CCVJ-conjugated bovine serum albumin strongly bound CCVJ and DCVJ. The CCVJ (or DCVJ) binding to IgG and Fab was accompanied by a drastic increase in fluorescence quantum yield, suggesting the restriction of intramolecular rotational relaxation about the donor-acceptor bond of the fluorophores. Nonspecific IgG never changed the quantum yield of the fluorophores. From the Scatchard plots, the association constants of CCVJ to IgG and Fab were 6.8 x 10(7) and 5.4 x 10(7) M-1, respectively, and the numbers of moles of CCVJ bound per mole of IgG and Fab were calculated to be 2.0 (+/- 0.1) and 1.0 (+/- 0.05), respectively. The fluorescence spectra of the IgG-bound CCVJ were quite similar to those of Fab-bound CCVJ. The fluorescence lifetimes of the IgG-bound and Fab-bound CCVJ were 388 and 383 ps at 25 degrees C, respectively. They were 6.3 times as long as the fluorescence lifetime of CCVJ free in solution (62 ps). These results indicated that the drastic increases in quantum yields were due to the decreases of the nonradiative rate constants of the antibody-bound CCVJ, as well as due to the changes of the intrinsic radiative rate constant, and that the nonradiative internal rotations about the donor-acceptor bond of CCVJ were not dependent on the size of the bound antibody molecules.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Small heat-shock protein is expressed in meningiomas and in granulofilamentous inclusion bodies.

FF cellular expression of estrogen receptor-related small heat-shock protein (HSP27) in meningiomas was investigated immunologically. A cytoplasmic distribution of HSP27 was demonstrated in surgical specimens of 22 of 26 cases with meningiomas and cultured meningioma cells derived from two individuals. By Western blotting, HSP27 was detected in every tissue homogenate of 17 cases studied. Thus, HSP27 appears to be constitutively expressed in most meningiomas. In anaplastic portions of one papillary meningioma, there were numerous granulofilamentous inclusion bodies [Goldman JE et al. (1980) Cancer 46:156-161]. The inclusion bodies were immunopositive for HSP27 despite the negativity of the tumor cytoplasms. Thus, HSP27 seems to participate in the formation of certain inclusion bodies in meningioma cells, like alpha B-crystallin which participates in the formation of Rosenthal fibers in astrocytes.

Adult↗