Biomedical subjects

S Takashima

Publications and source records attributed to S Takashima.

At least 199 records · Page 11Linked to original sources

PubMed1999

Connatal Pelizaeus-Merzbacher disease associated with the jimpy(msd) mice mutation.

In a patient with connatal Pelizaeus-Merzbacher disease with the same mutation in the proteolipid protein gene as in jimpy(msd) mice the immunohistochemical study of the brain demonstrated deficiencies of myelin and proteolipid protein despite good expression of myelin basic protein. The mechanism of myelination is partly disturbed by the mutation; therefore jimpy(msd) mice can be used as a suitable model for further studies in connatal Pelizaeus-Merzbacher disease.

Animals↗

PubMed1999

Periventricular leukomalacia: relation to gestational age and axonal injury.

Eighty-five infants ranging from 22 to 41 weeks gestation were diagnosed as having periventricular leukomalacia (PVL) using traditional neuropathologic methods. The lesions were also studied by immunocytochemistry for beta-amyloid precursor protein (beta-APP), a glycoprotein that has been observed in PVL. Using this technique, the distribution of white matter tissue necrosis was defined as focal, widespread, and diffuse. The type of PVL correlated with the gestational age at birth. The youngest infants tended to demonstrate widespread necrosis, and the oldest infants exhibited more focal necrosis. beta-APP immunopositivity was present in the axons around the foci of white matter necrosis in 76% of the patients and in the neurons of the adjacent cortex in 66% of the patients. In age-matched control patients, there was no beta-APP reactivity in the cerebral white matter or the cortex. In most patients the distribution of beta-APP-positive axons proved to be a useful marker for demonstrating the type of PVL; however, the relationship of beta-APP to the pathogenesis of PVL requires further study.

Amyloid beta-Protein Precursor↗

PubMed1999

Catecholaminergic neurons in the diencephalon and basal ganglia of SIDS.

The catecholaminergic systems of sudden infant death syndrome victims were examined in the diencephalon and basal ganglia, in addition to the midbrain, pons, and medulla oblongata, using the immuno-histochemical method involving tyrosine hydroxylase. A significant decrease in tyrosine hydroxylase immunoreactivity was demonstrated in the basal ganglia of sudden infant death syndrome victims between 2 to 12 months of age compared with age-matched control subjects. This change in the basal ganglia may be a secondary finding induced by chronic hypoxia or repeated ischemia in sudden infant death syndrome but suggests impairment of the development of the neuronal connection from the brainstem to the upper cardiorespiratory control in sudden infant death syndrome.

Basal Ganglia↗

PubMed1999

Fetal brain infection with human parvovirus B19.

Intrauterine parvovirus B19 infection is known to be one of the causes of hydrops fetalis. However, there are few reports of the pathologic changes in the central nervous system. Postmortem examination of a fetus revealed multinucleated giant cells of macrophage/microglia lineage and many small calcifications around the vessels, predominantly in the cerebral white matter. Parvovirus B19 genome DNA was detected in the nucleus of the multinucleated giant cells and solitary endothelial cells by polymerase chain reaction amplification and in situ polymerase chain reaction methods. Capsid antigen was also demonstrated in the cytoplasm of the endothelial cells by immunofluorescent assay. Thus, intrauterine B19 parvovirus infection could be associated with marked neuropathologic changes in the fetal brain at the midembryonal period. Neurologic follow-up of complications may be necessary for children who survive the intrauterine infection.

Adult↗

PubMed1999

Thalamocortical development of parvalbumin neurons in normal and periventricular leukomalacia brains.

To clarify disturbances in higher brain functions including cognition and learning disorders in preterm-born children, we investigated the functional development of the cerebral hemisphere, using parvalbumin (PA) immunohistochemistry in human subjects aged from 21 GW to 11 years of age. PA-immunoreactive neurons first appeared in the RNT at 24 GW, spread to the globus pallidus, and then to the VPoL and VPoM. At 38 GW, PA-immunoreactive neurons first appeared in layer 4 of the primary somatosensory cortex and auditory cortex, and comprised a dense band in layers 4 to 5 at 1 month of age. The developmental changes and course of PA expression in the early developmental stage corresponded to development of the thalamocortical connection and then to the functional development of cortical neurons. In preterm cases, PA expression was decreased in the cerebral cortices that corresponded to widespread or diffuse type PVL, but was increased in those with focal type PVL. These results indicate that accelerated expression of PA was induced by extra-uterine stimuli and a reduction of PA reflects the impairment of thalamocortical neurons.

Brain↗

PubMed1999

The early induction of cyclooxygenase 2 associated with neurofibrillary degeneration in brains of patients with Fukuyama-type congenital muscular dystrophy.

Brains of thirteen patients with Fukuyama-type congenital muscular dystrophy (FCMD) were evaluated regarding the expression of cyclooxygenase 2 (COX2), an enzyme involved in the synthetic pathway of prostaglandins and thromboxanes, as well as neurofibrillary tangles (NFT). The neuronal induction of COX2 was demonstrated with immunohistochemistry and Western blotting confirmed the up-regulation. Preceded by COX2 immunoreactivity, NFT-containing neurons appeared in the majority of FCMD patients without beta-amyloid deposition or senile plaques. The hippocampus did not demonstrate neurodegeneration, while, in other areas, neurons with NFT spread in a similar manner to Alzheimer's disease. NFT-bearing neurons were concomitantly shown to be immunoreactive to COX2. The precedent induction of COX2, therefore, may be related to the formation of NFT in this genetic disorder.

Adolescent↗

PubMed1999

Dopamine receptor upregulation in Lesch-Nyhan syndrome: a postmortem study.

The brains of two patients with Lesch-Nyhan syndrome (LNS) were studied. The concentration of dopamine was decreased in the caudate nucleus of LNS patients. Immunohistochemical methods revealed that the dopamine (DA) D1 and D2 receptor and methionine-enkephalin immunoreactivities (IRs) were increased in the putamen, and less significantly in the caudate nucleus. The D1 and D2 receptor IRs of the cingulate cortex, the tryptophan-hydroxylase IR in the dorsal nucleus of the midbrain, as well as the substance P and methionine-enkephalin IRs of the nociception-conducting structures, including the periaqueductal gray and spinal trigeminal nucleus, were not changed. Tyrosine-hydroxylase IR was not decreased in the substantia nigra of the LNS patients. Therefore, the cause of the decreased dopaminergic activity in LNS may not be involved in the production of tyrosine hydroxylase in the substantia nigra. Developmental abnormalities due to the DA defect at an early age might exist in the postsynaptic structure in the striatum.

Adolescent↗

PubMed1999

Changes of neurotransmitters in the brainstem of patients with respiratory-pattern disorders during childhood.

We examined neuropathologically and immunohistochemically the respiratory centers in the brainstem of two patients with Joubert syndrome (JS), three patients with congenital central hypoventilation syndrome (CCHS) and a patient with apneustic breathing (prolonged inspiratory pause) due to unknown etiology. Immunoreactivity (IR) of tryptophan hydroxylase (TPH) was decreased in the dorsal raphe nuclei of two patients with JS compared with age-matched controls, as well as in two patients with Dandy-Walker malformation. The two JS patients showed vermian defect and elongated cerebellar peduncles, and peculiar vascularities in the midline of the whole brainstem were also noted in one of these patients. These findings, as a whole, confirm that the midline structures of brainstem are disordered both structurally and functionally in JS, conceivably resulting in respiratory patterns and psychomotor deficits. IR of serotonin 1A receptor showed no significant changes in the medulla oblongata of these patients, however. In the parabrachial complex, IR of substance P was increased in two patients with CCHS, and one with apneustic breathing. IR of tyrosine hydroxylase was also increased in the latter. The brainstem of these patients showed reactive astrogliosis. These findings suggest preceding hypoxic episodes as well as an increased activity in the parabrachial complex which plays an important role in conducting the driving force to the medullary respiratory neurons from ascending sensory pathways.

Brain Stem↗

PubMed1999

Identification of an alpha2,6-sialyltransferase induced early after lymphocyte activation.

We have used mRNA differential display PCR to search for genes induced in activated T cells and we identified a gene encoding an alpha2,6-sialyltransferase (ST6GalNAc IV) that is rapidly induced in lymphocytes after antigen or mitogen stimulation. The 3.6 kb full-length cDNA clone (MK45) obtained contained a single open reading frame encoding a 302 amino acid protein and a 2.5 kb 3' untranslated region. MK45 expression in in vivo-activated CD8 T cells reached the highest level 4 h after antigen triggering and then declined rapidly to nearly base levels within 45 h. Northern blot analysis further revealed that MK45 expression was also induced in LPS-activated B cells and antigen-triggered CD4 T cells in vitro. MK45 expression was low or undetectable in most other mouse tissues examined, when compared to activated lymphocytes. Importantly, the mRNA expression level of other sialyltransferases remained largely unchanged during the early stage of lymphocyte activation. Finally, increased ecto-sialyltransferase activity and an altered sialylation pattern were demonstrated on the cell surface of early activated CD8 T cells. Our report identifies a candidate sialyltransferase gene that is involved in the early alteration of the sialylation pattern of cell surface molecules in activated lymphocytes.

Amino Acid Sequence↗

PubMed1999

A phase I/II study of continuous intra-arterial chemotherapy using an implantable reservoir for the treatment of liver metastases from breast cancer: a Japan Clinical Oncology Group (JCOG) study 9113. JCOG Breast Cancer Study Group.

BACKGROUND: Liver metastasis from breast cancer has a poor prognosis. While there are some reports of good response rates of hepatic metastasis from breast cancer by hepatic intra-arterial infusion chemotherapy, no phase I study including pharmacokinetic analysis has been reported. We performed a phase I/II study of intra-arterial infusion chemotherapy using adriamycin and 5-fluorouracil to find the maximum tolerated dose and response rate in patients with advanced or recurrent breast cancer. METHODS: A hepatic arterial catheter with an access port was inserted into the proper hepatic artery. Patients received 30 mg/m2 adriamycin on days 1 and 8 and 100 mg/m2 5-fluorouracil at level 1, 200 mg/m2 at level 2,300 mg/m2 at level 3 and 400 mg/m2 at level 4 continuously from day 1 through day 14 every 28 days. At least two cycles were required before evaluation. Twenty-eight patients were entered into this study and 26 patients were evaluable. Seventeen patients had hepatic metastasis only, although nine patients had additional metastasis to other sites. RESULTS: Dose-limiting toxicity of thrombocytopenia and neurotoxicity occurred at level 4. Leukocytopenia (ECOG grade 3-4) was observed in five (19%), thrombocytopenia in three (12%) and anemia in two (8%) patients. There were 11 catheter-related complications which were not dose dependent. Seven out of 13 evaluable patients (54%) responded at level 3. The median duration of response was 5.8 months (range, 1-23+) and median survival was 25.3 months (range, 6.2-54.7+). CONCLUSION: Hepatic arterial infusion therapy appears to be safe and effective but catheter-related complications must be overcome before starting a phase III trial.

Adolescent↗

PubMed1999

Purification and characterization of a novel vascular endothelial cell growth inhibitor secreted by macrophage-like U-937 cells.

A human histiocytic lymphoma cell line, U-937 cells, secretes several vascular endothelial cell growth inhibitors including leukemia inhibitory factor, oncostatin M, tumor necrosis factor-alpha, and transforming growth factor-beta1. Characterization of partially purified fractions from the conditioned media of phorbol ester-treated U-937 cells suggested the existence of unknown endothelial growth inhibitors. Using a combination of copper affinity, heparin affinity, cation exchange, and reversed phase liquid chromatographies, a growth inhibitor for endothelial cells was purified to homogeneity from conditioned media. The purified growth inhibitor migrated as a 65 kDa band on SDS-polyacrylamide gel electrophoresis under both reducing and nonreducing conditions. Microsequencing analyses of the tryptic fragments of the growth inhibitor and a BLAST search analysis revealed a unique sequence showing no homology to known proteins. The purified protein inhibited endothelial cell growth in a dose-dependent manner, but had no effect on smooth muscle cell growth. The factor also blocked endothelial cell growth induced by both fibroblast growth factor-2 and vascular endothelial growth factor, and was additively effective in inhibiting the growth of endothelial cells by U-937 cell-derived endothelial cell growth inhibitors. Thus, this factor appears to be a novel inhibitor with specificity for vascular endothelial cells, and is tentatively called endothelial cell inhibitor (ECI) in this study.

Animals↗

PubMed1999

Molecular cloning and expression of the novel fungal beta-glucosidase genes from Humicola grisea and Trichoderma reesei.

A novel fungal beta-glucosidase gene (bgl4) and its homologue (bgl2) were cloned from the cellulolytic fungi Humicola grisea and Trichoderma reesei, respectively. The deduced amino acid sequences of H. grisea BGL4 and T. reesei BGL2 comprise 476 and 466 amino acids, respectively, and share 73.1% identity. These beta-glucosidases show significant homology to plant beta-glucosidases belonging to the beta-glucosidase A (BGA) family. Both genes were expressed in Aspergillus oryzae, and the recombinant beta-glucosidases were purified. Recombinant H. grisea BGL4 is a thermostable enzyme compared with recombinant T. reesei BGL2. In addition to beta-glucosidase activity, recombinant H. grisea BGL4 showed a significant level of beta-galactosidase activity, while recombinant T. reesei BGL2 showed weak beta-galactosidase activity. Cellulose saccharification by Trichoderma cellulases was improved by the addition of recombinant H. grisea BGL4.

Amino Acid Sequence↗

PubMed1999

Inhibitory effect of telomere-mimic phosphorothioate oligodeoxy nucleotides (S-ODNS) on human tumor cell lines.

To clarify the inhibitory effect of telomere-mimic oligonucleotides on human cancer cell lines, we synthesized 18-mers (18T; n = 3), 24-mers (24T; n = 4) and 30-mers (30T; n = 5) of telomere-mimic phosphorothioate oligodeoxy nucleotides [5'-d(TTA GGG)n-3'] and examined their effects on the proliferation of human tumor cells by XTT assay. After 7 days of continuous exposure to 24T and 30T at concentrations ranging from 0.1 to 10 microM, concentration-dependent cell growth inhibition was observed in MCF-7 clone E3, ZR-75-1, MDA-MB 231, Colo 201 and WiDr. All of these cell lines highly expressed telomerase using the telomeric repeat amplification protocol. None of these tumor cell lines were affected by 18T. In MCF-7, ZR-75-1 and Colo 201 cell lines, a more than 50% growth inhibition was obtained by 3 microM of 24T and 30T whereas, in MDA-MB 231 and WiDr cell lines, cell growth inhibition was less than 50%. 30T was more effective than 24T. Estrogen-dependent growth of both MCF-7 and ZR-75-1 was inhibited by 3 microM of 24T and 30T, however, in the absence of estrogen, no growth inhibition was seen. The MCF-10A cell line, which was developed from normal human breast tissue and expressed telomerase only weakly, was inhibited by 10 microM of 18T. In conclusion, these observations indicate that S-ODNs inhibit tumor growth in cell lines expressing telomerase in a concentration-dependent manner and that cell growth inhibition is dependent on the length of S-ODNs. In addition, the short-length S-ODNs may inhibit growth of cells weakly expressing telomerase, but not of cells with high telomerase expression.

Breast Neoplasms↗

PubMed1999

Expression of transforming growth factor-beta 1 in periventricular leukomalacia.

The expression of transforming growth factor-beta 1, which has neurotrophic effects, was investigated in 25 neonates with periventricular leukomalacia using immunohistochemistry. In controls, transforming growth factor-beta 1 immunoreactivity was not detected in the cerebral white matter or cortex. Of the 25 cases of periventricular leukomalacia, transforming growth factor-beta 1 immunoreactivity was found in 16, and was distributed mainly in the cytoplasm of astrocytes, being prominent around necrotic foci in the white matter. The immunoreactivity was negative or weak at the acute stage of periventricular leukomalacia, and increased at the subacute stage and then decreased or was absent at the chronic stage. Astrocytes that were moderately or markedly positive for transforming growth factor-beta 1 were not found before 27 weeks' gestation, but were observed after 32 weeks' gestation in the white matter of the brains of neonates with periventricular leukomalacia. Transforming growth factor-beta 1 expression tended to be more obvious in focal periventricular leukomalacia than in widespread or diffuse periventricular leukomalacia. Our results suggest that transforming growth factor-beta 1 could be involved in the delayed glial response rather than the initial glial activation, and could play a role in the inhibition and repair of injury in periventricular leukomalacia. Exogenous transforming growth factor-beta 1 could have therapeutic potential for periventricular leukomalacia.

Brain↗

PubMed1999

Adenosine and cardioprotection in the diseased heart.

Biological and mechanical stressors such as ischemia, hypoxia, cellular ATP depletion, Ca2+ overload, free radicals, pressure and volume overload, catecholamines, cytokines, and renin-angiotensin may independently cause reversible and/or irreversible cardiac dysfunction. As a defense against these forms of stress, several endogenous self-protective mechanisms are exerted to avoid cellular injury. Adenosine, a degradative substance of ATP, may act as an endogenous cardioprotective substance in pathophysiological conditions of the heart, such as myocardial ischemia and chronic heart failure. For example, when brief periods of myocardial ischemia precede sustained ischemia, infarct size is markedly limited, a phenomenon known as ischemic preconditioning. We found that ischemic preconditioning activates the enzyme responsible for adenosine release, ie, ecto-5'-nucleotidase. Furthermore, the inhibitor of ecto-5'-nucleotidase reduced the infarct size-limiting effect of ischemic preconditioning, which establishes the cause-effect relationship between activation of ecto-5'-nucleotidase and the infarct size-limiting effect. We also found that protein kinase C is responsible for the activation of ecto-5'-nucleotidase. Protein kinase C phosphorylated the serine and threonine residues of ecto-5'-nucleotidase. Therefore, we suggest that adenosine produced via ecto-5'-nucleotidase gives cardioprotection against ischemia and reperfusion injury. Also, we found that plasma adenosine levels are increased in patients with chronic heart failure. Ecto-5'-nucleotidase activity increased in the blood and the myocardium in patients with chronic heart failure, which may explain the increases in adenosine levels in the plasma and the myocardium. In addition, we found that further elevation of plasma adenosine levels due to either dipyridamole or dilazep reduces the severity of chronic heart failure. Thus, we suggest that endogenous adenosine is also beneficial in chronic heart failure. We propose potential mechanisms for cardioprotection attributable to adenosine in pathophysiological states in heart diseases. The establishment of adenosine therapy may be useful for the treatment of either ischemic heart diseases or chronic heart failure.

5'-Nucleotidase↗

PubMed1999

Improvement by 5-amino-4-imidazole carboxamide riboside of the contractile dysfunction that follows brief periods of ischemia through increases in ecto-5-nucleotidase activity and adenosine release in canine hearts.

5-Amino-4-imidazole carboxamide (AICA) riboside increases adenosine release in ischemic myocardium, suggesting that AICA riboside improves contractile dysfunction. In 49 open-chest dogs, contractile function assessed by fractional shortening (FS) was observed 3 h after the onset of reperfusion following 15 min of occlusion of the left anterior descending coronary artery. During reperfusion, the treatment with AICA riboside increased adenosine concentration in the coronary venous blood (536+/-44 vs. 281+/-21 pmol/ml at 3 min of reperfusion, p<0.001) and peak coronary hyperemic flow (367+/-13 vs. 300+/-21 ml/100 g per min, p<0.001) when compared with the untreated group. FS at 3h of reperfusion increased in the AICA riboside group (21.1+/-2.3 vs. 12.8+/-0.6% in the untreated group, p<0.001). AICA riboside increased myocardial ecto-5'-nucleotidase activity. Administration of adenosine also augmented coronary hyperemic flow and increased FS to the levels of the AICA riboside group. Either 8-phenyltheophylline (an antagonist of adenosine receptors) or alpha,beta-methylene-adenosine 5'-diphosphate (an inhibitor of ecto-5'-nucleotidase) completely abolished the increased coronary hyperemic flow and improvements of myocardial contractile function due to AICA riboside. Thus it was concluded that AICA riboside improves the contractile dysfunction that follows a brief period of ischemia via adenosine-dependent mechanisms.

5'-Nucleotidase↗

PubMed1999

Isolation and characterization of the actin gene from the cellulolytic fungus Humicola grisea and analysis of transcription levels of actin and cellulase genes.

An actin gene was isolated from the cellulolytic fungus Humicola grisea. The gene structure, which has 5 introns in the coding region, is similar to those of the so far cloned fungal actin genes. But there are some differences in intron sizes and codon usage. Transcription levels of actin and cellulase genes were also investigated.

5' Untranslated Regions↗

PubMed1999

Correlation between magnetic resonance imaging and clinical profiles of periventricular leukomalacia.

Magnetic resonance imaging (MRI) findings of 70 children with periventricular leukomalacia (PVL), examined between 1 year 2 months and 8 years of age (mean: 2 years 4 months of age), were analysed. Neurological assessments were made between 1 year 3 months and 15 years (mean: 4 years 9 months). The possible correlations between MRI findings and clinical profiles of PVL were investigated using three parameters of the MRI findings. The grade of ventriculomegaly correlated well with the severity of cerebral palsy (CP) but not with the severity of mental impairment. The grade of reduction of periventricular white matter correlated well with the severity of CP and mental impairment, and is the most reliable parameter for neurological prognosis. The degree of periventricular hyperintensity on T2-weighted images did not correlate well with severity of CP, but correlated to some degree with mental impairment. There was a significantly lower degree of periventricular hyperintensity in children at less than 28 weeks of gestation than at 28 or more weeks of gestation, but no significant difference in other parameters. The periventricular hyperintensity should be evaluated in view of the gestational age.

Cerebral Ventricles↗