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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 523 records · Page 29Linked to original sources
PubMed1994

Bone matrix decorin binds transforming growth factor-beta and enhances its bioactivity.

In an effort to clarify the regulation of distribution and actions of transforming growth factor (TGF)-beta in bone, TGF-beta 1 binding to extracted bone matrix proteins and the influence of such binding on TGF-beta 1 actions were examined. In-gel binding of 125I-TGF-beta 1 using extracts from mineralized bovine bone matrix demonstrated that 125I-TGF-beta 1 was almost exclusively bound to a proteoglycan, decorin. The binding was via the core protein of decorin. Scatchard analysis of the binding of 125I-TGF-beta 1 to immobilized decorin purified from osteoblastic MC3T3-E1 cell conditioned medium revealed that there were two specific binding sites with high and low affinities for TGF-beta 1 (Kd = 0.3 and 5 nM, respectively). The addition of decorin along with TGF-beta 1 enhanced the inhibitory effect of TGF-beta 1 on MC3T3-E1 cell proliferation. Decorin in itself did not affect their proliferation. These cells possessed types I and II TGF-beta receptors and betaglycan, and the addition of decorin increased the binding of 125I-TGF-beta 1 to all these receptors. These results demonstrate that the core protein of decorin specifically binds TGF-beta 1 with high affinities and that the binding of TGF-beta 1 to decorin increases TGF-beta 1 binding to its receptors and enhances its bioactivity. Because TGF-beta is released by bone resorption along with matrix proteins, including decorin, and because it stimulates the synthesis of these proteins, it is suggested that the binding and enhancement of the activities of TGF-beta by decorin may play a role in maintaining bone formation during bone remodeling process.

3T3 Cells↗
PubMed1994

Visualization and function of vimentin phosphorylation by cdc2 kinase during mitosis.

To investigate the role of intermediate filament (IF) protein phosphorylation by cdc2 kinase during mitosis, we developed a monoclonal antibody 4A4 recognizing Ser55-phosphorylated vimentin. Western blotting indicated that this antibody reacted with vimentin phosphorylated by cdc2 kinase but not with non-phosphorylated vimentin or with vimentin phosphorylated by other kinases such as cAMP-dependent protein kinase, protein kinase C, or Ca(2+)-calmodulin-dependent protein kinase II. Immunofluorescence and immunoelectron microscopy showed that vimentin Ser55 residues distributed in the entire cytoplasmic vimentin filament system are phosphorylated when the cells enter mitosis and dephosphorylated in cytokinesis. All cell lines examined showed a similar appearance of immunoreactivity with antibody 4A4. Fractionation of mitotic cell extracts on Mono-Q Sepharose revealed a single peak of vimentin Ser55 kinase activity, and the anti-p34cdc2 antibody reacted with the 34 kDa band in the kinase containing fractions. Vimentin Ser55 kinase activities were nil in the interphase cell extract. Immunofluorescent evidence using antibody 4A4 and biochemical analysis using vimentin Ser55 peptide showed that the degree of disassembly of vimentin filament of various cell types at early mitotic phase correlated well with the amount of mitotically activated cdc2 kinase.

Amino Acid Sequence↗
PubMed1994

Regional difference in the neurotoxicity of ochratoxin A on the developing cerebral cortex in mice.

Pregnant mice were treated intraperitoneally with 3 mg/kg of ochratoxin A on day 10 of gestation. They were allowed to give birth and the offspring were killed at 6 weeks of age for observation. Prenatal exposure to ochratoxin A caused microcephaly in offspring. Their body weight, brain weight, cortical thickness and numerical densities of neurons and synapses in somatosensory and visual cortex were examined. The mice exposed in utero to ochratoxin A showed a significant deficit in brain weight compared to the age-matched control, but there was no significant difference in body weight between these two groups. The cortical thickness showed a significant decrease in both somatosensory and visual cortex. Normal control mice had about 66,000 neurons/mm3, while age-matched ochratoxin A-treated mice had about 91,000 neurons/mm3 in somatosensory cortex. There was a significant increase in OA-treated group. However, there was no significant difference in the numerical density of neurons in visual cortex. On the other hand, there was no significant difference in the numerical density of synapses in both somatosensory and visual cortex. The somatosensory cortex of control mice had about 13,000 synapses per neuron, whereas ochratoxin A-treated mice had about 9,400 synapses per neuron. In the visual cortex, no significant difference was seen in synapse-to-neuron ratios. The discrepancy in the numerical density of neurons and synapse-to-neuron ratios between the somatosensory and visual cortex might derive from a time difference in cortical neurogenesis.

Aging↗
PubMed1994

Circadian variations of amino acid content of suprachiasmatic nucleus in rats.

The suprachiasmatic nucleus (SCN) has been known as an oscillator of circadian rhythm and recently some reports suggested that excitatory amino acids were functioning in this nucleus. The purpose of this study is to measure the physiological amino acid content of this nucleus, to estimate the circadian variation in amino acids and the effect of light on amino acid content in the SCN. The content of aspartate, asparagine, glycine and serine tended to be lower in the light phase compared to the dark, but was not significant. As to the light effect on amino acid content of the SCN, only aspartate decreased when a light pulse was applied. These results suggest that aspartate is involved in the transmission of photic information within the SCN.

Amino Acids↗
PubMed1994

Monoamine metabolites in the cerebrospinal fluid in infantile spinal muscular atrophy.

Analyses of tryptophan and tyrosine metabolites in cerebrospinal fluid were performed to examine an abnormality of the monoamine neurone system in severe infantile spinal muscular atrophy (SMA type I). The levels of 5-hydroxyindoleacetic acid and homovanillic acid were significantly lower than those in controls. Decreases in the concentration of 5-hydroxyindoleacetic acid and kynurenine seemed to be related to the severity of SMA type I. These results suggest that the monoamine neurone system may play a role in the pathophysiology of SMA type I.

Biogenic Monoamines↗
PubMed1994

Asbestos and nonasbestos fiber content in lung tissue of Japanese patients with malignant mesothelioma.

BACKGROUND: Pulmonary fiber content of both asbestos and nonasbestos types were evaluated in Japanese patients with malignant pleural mesotheliomas. METHODS: Pulmonary fiber content was analyzed in 16 patients and 16 case-matched control subjects by transmission electron microscopy with energy-dispersive X-ray analysis using a low-temperature ashing procedure. RESULTS: The geometric mean content of total asbestos was significantly higher in the patients (22.0 x 10(6) fibers/g dry lung) than in the control subjects (2.24 x 10(6) fibers/g dry lung) (P < 0.01). When the asbestos content was analyzed by fiber type, the geometric means were also consistently and significantly higher among the patients compared with the control subjects (P < 0.01). Results were as follows: (1) amosite: patients 3.94 times 10(6) versus control subjects 0.23 x 10(6); (2) crocidolite: patients 3.56 times 10(6) versus control subjects 0.35 times 10(6); (3) total amphiboles: patients 16.0 times 10(6) versus control subjects 0.77 times 10(6); and (4) chrysotile: patients 3.76 times 10(6) versus control subjects 1.01 times 10(6). However, when individual total asbestos content was considered, 7 of the 16 patients (44%) had levels lower than the highest value noted among the control subjects. Pulmonary fiber content of patients and control subjects also revealed the presence of nonasbestos fibers. The geometric mean of nonasbestos fibers was significantly higher in the patients (87.3 x 10(6)) than in control subjects (33.8 x 10(6)) (P < 0.01). The major type of nonasbestos fibers in both groups was aluminum silicates. The mean of ratios of nonasbestos fiber contents to total asbestos contents in the patients and control subjects was 7.0 and 17.3, respectively. CONCLUSIONS: The results were mainly in agreement with the findings of earlier investigations, but fiber content of both chrysotile and nonasbestos fiber as well as those of amphibole asbestos were significantly higher in the patients than in the control subjects.

Adult↗
PubMed1994

Influences of aging and sex on renal pelvic carcinogenesis by N-butyl-N-(4-hydroxybutyl)nitrosamine in NON/Shi mice.

Influences of aging and sex on renal pelvic carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) were examined in 6-, 15 -and 45-week-old male and female NON/Shi mice. Histopathological examination revealed an age-related shortening of induction time for renal pelvic carcinomas in males, although actual incidences did not increase. The histological patterns of carcinomas induced in both renal pelvis and urinary bladder demonstrated male mice to be more prone to develop transitional cell carcinomas, while squamous cell carcinomas were more likely to arise in females. Moreover, the sex factor appeared to influence the progression of both renal pelvic and urinary bladder carcinomas.

Aging↗
PubMed1994

Effect of phenacetin pretreatment on renal pelvic carcinogenesis by N-butyl-N-(4-hydroxybutyl)nitrosamine in NON/Shi mice of both sexes.

Influences of phenacetin (PH) pretreatment on renal pelvic carcinogenesis induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) were examined in NON/Shi mice of both sexes. Histopathological examination revealed that PH pretreatment enhanced not only the induction of urinary tract carcinoma but also distant metastasis of renal pelvic carcinoma by BBN in male mice. The high incidence of urinary tract carcinoma by PH pretreatment might be due to hydronephrosis and epithelial proliferative lesions enhanced by PH, since a single treatment of PH induced hydronephrosis in all mice and simple hyperplasia in 70-80% of mice used.

Animals↗
PubMed1994

Bcl-2 expression in the thymus and periphery.

Bcl-2 proto-oncogene is expressed in normal lymphoid tissues and its role has been suggested to involve the selection of B and T cells. Here we report three-color flow cytometric studies on the expression of bcl-2 protein in the thymus and periphery. Bcl-2 was expressed in the majority of T and B cells and down-regulated only in the CD1+, CD3- to low, CD4+8+ thymocytes, and the B cells that are in cell cycle in the tonsil and lymph node. In contrast, the CD2+, CD1-3-4-8-19-, early T cells, and mature single positive cells in the thymus, as well as the tonsilar and lymph node T cells, irrespective of their cell cycle status, expressed bcl-2. These results are consistent with the notion that bcl-2 is down-regulated in the T and B cells that are in the process of generating new antigen receptors and subject to subsequent positive selection.

Adult↗
PubMed1994

Determination of 3,4-dimethylhippuric acid as a biological monitoring index for trimethylbenzene exposure in transfer printing workers.

The relationship between exposure to 1,2,4-trimethylbenzene (1,2,4-TMB) and urinary concentration of 3,4-dimethylhippuric acid (3,4-DMHA), one of its metabolites, was studied in workers involved in transfer printing. Airborne TMBs were sampled by an organic vapor monitoring badge and analyzed by capillary gas chromatography. Urinary 3,4-DMHA and creatinine were analyzed under the same conditions of high-performance liquid chromatography. The exposure concentration of 1,2,4-TMB among workers was around 25 ppm, the threshold limit value (TLV). The urinary concentration of 3,4-DMHA was low at the start of each shift and high at the end. Exposure to the TLV (25 ppm) of 1,2,4-TMB results in a urinary 3,4-DMHA concentration of 410 mg/g creatinine (r = 0.897, P < 0.001). Urinary 3,4-DMHA concentration could be used as a biological monitoring index for 1,2,4-TMB exposure.

Adult↗
PubMed1994

Predator-prey dynamics in models of prey dispersal in two-patch environments.

Models are presented for a single species that disperses between two patches of a heterogeneous environment with barriers between patches and a predator for which the dispersal between patches does not involve a barrier. Conditions are established for the existence, uniform persistence, and local and global stability of positive steady states. In particular, an example that demonstrates both the stabilizing and destabilizing effects of dispersion is presented. This example indicates that a stable migrating predator-prey system can be made unstable by changing the amount of migration in both directions.

Animals↗
PubMed1994

Hyperproinsulinemia in Japan.

Four families with hyperproinsulinemia found in Japan were described. The details of the first case, who was investigated by Kanazawa et al., were reported and the similarity of the first case to the following cases was shown. Arginine 65 of the proinsulin molecule might be a hot spot of the insulin gene. A possible abnormality of insulin release in affected individuals was disclosed by investigation of the family members of the first case.

Arginine↗
PubMed1994

The core and complementary sequence responsible for biological activity of the diapause hormone of the silkworm, Bombyx mori.

To evaluate the structure-function relationship of the diapause hormone of the silkworm, Bombyx mori, the entire molecule and selected fragment and deleted analogues were chemically synthesized to compare their biological activity. The C-terminal pentapeptide amide was the shortest fragment that elicited 11% diapause eggs at maximum, indicating that this sequence is the core-active structure required for a biological response. The full biological response of about 70% diapause eggs was expressed by the C-terminal hexapeptide amide. However, an ED50 value of this peptide amide was 1000-fold higher than that of the parent molecule. The serial elongation of peptide chain lengths toward the N-terminus brought about the sudden decrease in ED50 values at two positions between Arg9-Gly10 and Thr1-Asp2. The deletion of duplicated sequence(s) located in the middle part of the molecule or the truncation of N-terminal region of the parent molecule increased ED50 values but had no effects on response. Thus, N-terminal region and duplicated sequences act as the complementary structures for full potency of diapause hormone.

Amino Acid Sequence↗
PubMed1994

Patient with unusual Hutchinson-Gilford syndrome (progeria).

A patient with unusual Hutchinson-Gilford syndrome (progeria) is reported. This 7-year-old boy had all the characteristics of progeria, except for coxa valga and the "horse-riding" stance. A previous cerebral infarction was detected in the right putamen on cranial magnetic resonance imaging. During treadmill exercise test electrocardiography, ST depression suggested the existence of arteriosclerotic lesions. Skin fibroblast culture exhibited 76% DNA-repair capacity compared to normal. He has not manifested endocrinologic abnormalities. From these findings it is concluded that this patient has an incomplete case of Hutchinson-Gilford syndrome and that a correlation may exist between the clinical features and the degree of DNA-repair capacity.

Biopsy↗
PubMed1994

Patient with unusual alternating hemiplegia.

A patient with unusual alternating hemiplegia in childhood is reported. The frequency of hemiplegic episodes was lower than that in other reported patients. Interictal positron emission tomography revealed decreased cerebral blood flow in the left hemisphere. After cerebral angiography, postanesthetic irritability occurred which evolved into coma with hemiplegic episodes. We believe that cerebral angiography in a child with alternating hemiplegia may cause hemiplegic episodes and coma. The episodes disappeared almost completely for 6 years after treatment with flunarizine, thus indicating the benefit of the medication for the treatment of alternating hemiplegia.

Basal Ganglia↗
PubMed1994

Serial MRI in infantile bilateral striatal necrosis.

A 3-year-old girl with left hemiparesis suffered from bilateral paresis, motor rigidity, gait disturbance, axial hypotonia, dysarthria, apathy, and incontinence. After steroid therapy, mild improvement occurred, but muscle weakness, gait disturbance, and rigidity remained. Leigh encephalopathy was excluded on the basis of muscle biopsy and laboratory findings. Computed tomography and serial magnetic resonance imaging at an early stage revealed right-sided dominant lesions in the putamen and caudate nucleus and later bilateral striatal lesions, appearing as hyperintense signals on T2-weighted images and mixtures of hypo- and hyperintense signals on T1-weighted images. This is the first demonstration of serial magnetic resonance imaging findings in infantile bilateral striatal necrosis.

Basal Ganglia Diseases↗
PubMed1994

A case of bacterial meningitis complicated by post-traumatic cerebrospinal fluid rhinorrhea.

This paper reports an 11 year old boy with bacterial meningitis accompanied by post-traumatic cerebrospinal fluid (CSF) rhinorrhea. Streptococcus pneumoniae was cultured from CSF. The clinical course was very rapid before admission and his age relatively high for usual bacterial meningitis. Consequently, we examined the cause in detail. Immunological findings were within normal limits. Although routine graphic examinations, such as cranial X-ray photography, horizontal cranial computed tomography (CT) and magnetic resonance imaging, could not demonstrate a bone defect, both coronal thin-section cranial CT scanning and radioactive isotope counting by means of cotton packed into the nasal cavity were useful for detecting CSF rhinorrhea. In a case of atypical meningitis, the past history should be examined with caution and coronal thin-section CT should be performed.

Cerebrospinal Fluid Rhinorrhea↗