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Biomedical subjects

H Tsuchiya

Publications and source records attributed to H Tsuchiya.

At least 109 records · Page 6Linked to original sources
PubMed1996

A method for evaluating the cariogenicity of oral bacteria using radio-labelled synthetic hydroxyapatite.

Radioactive hydroxyapatite was synthesized using 45Ca to evaluate the cariogenicity of oral streptococci. Discs prepared from it were suspended in media containing sucrose, then inoculated with Streptococcus mutans or Streptococcus sanguis. The radioactivity in the supernatant fluid was measured at specified time intervals. Released 45Ca in the supernatant fluids markedly increased in both species during the experimental period, while Strep. mutans showed much higher decalcification than Strep. sanguis. The present method would be useful for semi-quantitative evaluation of bacterial decalcification ability.

Calcium Radioisotopes↗
PubMed1996

Effect of estrogen replacement therapy on hepatic triglyceride lipase, lipoprotein lipase and lipids including apolipoprotein E in climacteric and elderly women.

Estrogen provides beneficial effects on hyperlipidemia in climacteric and elderly women. In this study of 68 women (37 to 67 years old), hepatic triglyceride lipase (HTGL), lipoprotein lipase (LpL) serum lipids and apolipoproteins were analyzed to investigate the effects of estrogen replacement therapy (ERT). After menopause, LpL, total cholesterol, low-density lipoprotein (LDL)-cholesterol, and apolipoprotein B increased. But ERT suppressed total cholesterol, LDL-cholesterol, apolipoprotein B, and especially apolipoprotein E in menopausal women. The mechanism was thought that ERT significantly suppressed HTGL, but LpL was not affected. Estrogen also increases hepatic LDL receptors and accelerates transfer of serum LDL-C (and TC). It was said that HTGL accelerates conversion of intermediate-density lipoprotein (IDL) to LDL. The suppression of HTGL by the ERT may decrease conversion of IDL to LDL and lower LDL-C (and TC). These estrogen's beneficial effects on lipids, may prevent the atherosclerosis. In addition, apolipoprotein E increases senile plaques in senile dementia-Alzheimer's type. The decrease in apolipoprotein E with ERT may be related to cognitive functions of elderly women.

Adult↗
PubMed1996

[Influence of social environments on brain aging].

To investigate influence of social activity on normal brain aging, we studied the social activity score, cognitive functions, self-rating depression scale, cerebral blood flow (CBF), MRI and motor function in the normal elderly people living in different social environments. There was no difference in risk factors for stroke, MRI findings and CBF between the two groups. However, the subjects living in a home for elderly showed significantly lower social activities than those living with families. Cognitive functions and motor function were lower, and SDS was higher in subjects living in retirement house than those living with families. The social environment including social activities closely related to life style may significantly influence brain aging with regard to silent brain infarctions or risk factors for stroke.

Aged↗
PubMed1996

Matrix metalloproteinase 9 (gelatinase B) is expressed in multinucleated giant cells of human giant cell tumor of bone and is associated with vascular invasion.

Human giant cell tumor (GCT) consists of multinucleated giant cells and mononuclear stromal cells, and is characterized by frequent vascular invasion without distant metastases. To study the role of matrix metalloproteinases (MMPs) in the vascular invasion, we examined production of MMP-1 (tissue collagenase), -2 (gelatinase A), -3 (stromelysin-1), -9 (gelatinase B), and tissue inhibitors of metalloproteinases (TIMP-1 and -2) in GCT. MMP-9 was highly and predominantly expressed in giant cells by both immunohistochemistry and in situ hybridization. Expression of other MMPs was also observed in some cases but was inconstant. Sandwich enzyme immunoassays demonstrated that MMP-9 is the predominant MMP secreted by GCT. There was a definite imbalance between the amounts of MMP-9 and those of TIMPs in the culture media of GCT, leading to detectable gelatinolytic activity in an assay using 14C-gelatin. Gelatin zymography demonstrated the main activity at about 90 kd, which was identified as the zymogen of MMP-9 by immunoblotting. Immunohistochemistry for type IV collagen and laminin, major basement membrane components, showed that disappearance of the proteins is closely associated with MMP-9-positive giant cells. These results indicate the production of MMP-9 by multinucleated giant cells and suggest that the metalloproteinase may contribute to proteolysis associated with vascular invasion and local bone resorption in human GCT.

Adolescent↗
PubMed1996

The Ilizarov method in the management of giant-cell tumours of the proximal tibia.

We have used the Ilizarov technique for the management of subarticular defects after the excision of giant-cell tumours in the proximal tibia in five patients. The defect was reconstructed with a segment of 5 to 6 cm obtained from the diaphysis of the affected tibia and by autogenous bone graft from the iliac crest. The newly developed defect in the diaphysis was reconstructed by distraction using the Ilizarov apparatus. Bone grafting at the docking site was performed soon after positioning the bone segments. The mean length of the bone defect was 5.7 cm and the mean duration of external fixation was 233 days. The relative blood flow in the leg measured by 99mTc angiography increased by 1.7 to 2.3 times that of the control level during distraction and consolidation. When seen at a mean of 43 months all patients showed a normal range of motion in the knee and ankle with no collapse of the articular surfaces.

Adolescent↗
PubMed1996

[Detection of PEBP2 beta/MYH11 fusion mRNA in acute myelomonocytic leukemia without marrow eosinophilia].

We present a 15-year-old woman with acute myelomonocytic leukemia without marrow eosinophilia, M4 in the FAB classification. She was admitted to our hospital with nausea and headaches. Upon admission, the leukocyte count was 284,000/microliters with 95% leukemic cells. The bone marrow aspirate was hypercellular with 74.8% blasts and 0.2% eosinophils. Leukemic cells were positive for myeloperoxidase and esterase staining. Initially, the karyotype of the bone marrow cells on admission was considered to be normal. However, the PEBP2 beta/MYH11 fusion transcript was detected in the bone marrow mononuclear cells by using the reverse transcriptase-polymerase chain reaction (RT-PCR). Reevaluation of karyotypes showed a t(16;16) (p13;q22) in the bone marrow cells. After achieving complete remission, she was treated with low-dose etoposide. Chromosome analysis showed a normal karyotype and no amplified chimeric transcripts were observed. This case indicates that the molecular analysis of PEBP2 beta and MYH11 genes is a useful tool to detect inv (16) and t(16;16) which were often difficult to find, and that leukemic cells from some cases of M4 without marrow eosinophilia have these chromosome abnormalities.

Adolescent↗
PubMed1996

[Intraoperative use of plasma-derived activated factor VII (F VII a) in a hemophilia A patient with inhibitors].

We treated a 1-year 9-month-old boy with severe hemophilia A who developed high level of F VIII inhibitor. A placement of an implantable intravenous access device was scheduled under general anesthesia. After a slow induction using oxygen, nitrous oxide and sevoflurane, a peripheral venous line was placed and plasma-derived F VII a was infused. A catheter was inserted via the jugular vein to the SVC and it was connected to the device placed subcutaneously in his right chest wall. The peroperative blood loss was slight, and anesthesia and surgery went uneventfully.

Anesthesia, General↗
PubMed1995

Formation of tetrahydro-beta-carbolines in human saliva.

When human saliva obtained after cigarette smoking was incubated in the presence of tryptamine, the formation of 1,2,3,4-tetrahydro-beta-carboline (TBC) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) was observed in a short time. After incubation with tryptamine (2.5 micrograms/microliter) for 10 min, the concentrations of TBC and MTBC formed were 3.27 +/- 0.94 and 0.35 +/- 0.17 ng/microliter, respectively. The formation of TBC and MTBC in intact saliva and in saliva heated at 100 degrees for 10 min was compared, but no significant difference was found. The analysis of foodstuffs showed that significant amounts of tryptamine were contained in various foods and beverages. The analysis of cigarette smoke solutions and immersion solutions of denture-base acrylic resins showed that ng-micrograms/microliter levels of formaldehyde and acetaldehyde were contained in cigarette smoke and leached from dental resins. These results indicate that both precursors, tryptamine and aldehydes, coexist in oral environments and that their interaction to form TBC and MTBC potentially occurs in human saliva without participation of salivary enzyme.

Adult↗
PubMed1995

Cellular fatty acids and aldehydes of oral Eubacterium.

The cellular fatty acids and aldehydes of oral Eubacterium species were determined by gas chromatography-mass spectrometry. E. brachy and E. lentum contained mainly branched-chain fatty acids, whereas the others contained straight-chain acids. E. brachy, E. lentum, E. yurii ssp. yurii, E. yurii spp. margaretiae, E. limosum, E. plauti and E. aerofaciens also contained aldehydes with even carbon numbers. In addition to species-specific components, the compositional ratios of fatty acids and aldehydes characterized each individual species. The 10 species tested were divided into 5 groups by the principal component analysis. Cellular fatty acids and aldehydes would be chemical markers for interspecies differentiation of oral Eubacterium.

Aldehydes↗
PubMed1995

Molecular genetic basis of renal carcinogenesis in the Eker rat model of tuberous sclerosis (Tsc2).

We have recently identified on rat chromosome 10q a germline mutation in the tuberous sclerosis gene (Tsc2), the gene predisposing to renal carcinoma (RC) in the Eker rat. The homozygous mutant condition is lethal at around the 13th day of fetal life. In heterozygotes, RCs invariably develop in the first year of life. Histologically, RCs develop through multiple stages from early preneoplastic lesions (i.e., phenotypically altered tubules) to adenomas. The wild-type allele mutation has been found even in the earliest preneoplastic lesions, fitting Knudson's two-hit hypothesis and supporting the hypothesis that Tsc2 is a tumor suppressor gene. In this study, homozygous deletion of the Ink4 homologue on rat chromosome 5q was observed in 14 of 24 (58%) RC-derived cell lines. This may represent involvement of a second tumor suppressor gene, contributing to tumor progression. Considering previous results of studies of homozygous deletion of the Ifn alpha gene in five of 24 cases (21%) and the Ifn beta gene in one of 24 cases (4%), the order of the genes may be Ink4-Ifn alpha-Ifn beta. Microsatellite instability was not observed in 26 Eker rat tumors.

Amino Acid Sequence↗
PubMed1995

Renal carcinogenesis in the Eker rat.

The Eker rat hereditary renal carcinoma is an excellent example of a Mendelian dominant predisposition to a specific cancer in an experimental animal. We recently reported that a germline insertion in the rat homologue of the human tuberous sclerosis (TSC2) gene gives rise to the dominantly inherited cancer in the Eker rat model. The function of the TSC2/Tsc2 gene product (called "tuberine" in the human case) is not yet understood, although it contains a short amino acid sequence homologous to the ras family GTPase-activating proteins (GAP3). In the study, we isolated subtracted cDNA clones having increased expression in Eker renal carcinoma cells, using a modified representational difference analysis method to search for additional genes specifically involved in renal carcinogenesis. Here we identified four genes: the third component of the complement (C3) gene, the fos-related antigen I (fra-1) gene, an unknown gene (designated as being expressed in renal carcinoma: erc) and the calpactine I heavy-chain (Annexin II) gene.

Animals↗
PubMed1995

Perirenal mass of Langerhans cell histiocytosis.

A 15-month-old girl with Langerhans cell histiocytosis (LCH), Letterer-Siwe disease, was referred to our hospital in 1984. Whilst on treatment with cytotoxic drugs, a perirenal mass was detected and hydronephrosis became evident when she was 29 months old. Percutaneous nephrostomy tubes were placed in the pelvis, bilaterally and replaced every 6 months. The mass was not completely controlled and chronic pyelonephritis continued. Biopsy of the mass convoluted kidney hilus revealed histiocytic invasion. Although multiple organ systems are involved in LCH and abdominal malignant tumours may be accompanied by hydronephrosis, to our knowledge, this is the first case report of abdominal LCH and the ensuing hydronephrosis. Percutaneous nephrostomy tubes proved useful, but more convenient, less painful and infection-limited approaches need to be designed.

Abdominal Neoplasms↗
PubMed1995

Electrophysiologic correlates of visuo-spatial attention shift.

We investigated neurophysiologic correlates of shifting visual attention across the visual field. Event-related potentials (ERPs) were recorded in 12 normal subjects during a visual discrimination task in which target stimuli were presented at a predictable or unpredictable location in the eccentric visual field. Subjects were obliged to shift their attention from the expected site to the unpredictable site immediately after the presentation of shifted stimuli in order to detect the change of stimulus attributes. Shifted stimuli modulated the N1 component (130-200 msec), producing a larger amplitude at the posterior temporal site contralateral to the stimulus field and a smaller amplitude over the ipsilateral hemisphere. Furthermore, shifted stimuli uniquely evoked a positive ERP component with a latency of 200-300 msec, which distributed broadly over the skull maximally at the frontal and central electrode sites. Both the negative and positive components changed in amplitude as a function of shift distance and direction. These results suggest that modulations of the negative and positive deflections reflect the shift of covert visuo-spatial attention and that right hemispheric dominance does not exist at least in the early stage of shifting spatial attention.

Adult↗
PubMed1995

Metabolic hydroxylation of 1-methyl-1,2,3,4-tetrahydro-beta-carboline in humans.

We characterized the metabolites of 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) in human urine by gas chromatography-negative ion chemical ionization mass spectrometry (GC-NICIMS) and developed an analytical method using GC-NICIMS for their quantitative determination. When tetradeuterated MTBC was orally administered to a human subject, two peaks of the deuterated metabolites appeared on mass fragmentograms of the urine samples after administration. They were identified as tetradeuterated 6-hydroxy-MTBC (6-OH-MTBC) and 7-hydroxy-MTBC (7-OH-MTBC), indicating that MTBC was metabolically hydroxylated in humans. The proposed GC-NICIMS method could sensitively and selectively determine urinary 6-OH-MTBC and 7-OH-MTBC without interference from their artifactual formation during analysis. Its application to urine analysis has revealed that MTBC is excreted in human urine predominantly as the two hydroxylated metabolites, in which 6-OH-MTBC is present in both free and conjugated forms, whereas the 7-OH-MTBC of a conjugated form is much more than the 7-OH-MTBC of a free form.

Carbolines↗
PubMed1995

Exogenous expression of human granulocyte colony-stimulating factor receptor in a B-lineage acute lymphoblastic leukemia cell line: a possible model for mixed lineage leukemia.

We report evidence that the granulocyte colony-stimulating factor (G-CSF) receptor is present and may be functioning on blast cells from some patients with myeloid surface antigen positive (My+) acute lymphoblastic leukemia (ALL). In the present study, a human G-CSF receptor expression plasmid was transfected into a newly established B-lineage ALL cell line 'Tanoue' and its subclone 'ST' by lipofection to investigate whether expression of the G-CSF receptor and G-CSF stimulation would induce myeloid characteristics on myeloid surface antigen negative (My-) ALL cells. The G-CSF receptor became detectable on the transfected cells (GR-Tanoue and GR-ST), with dissociation constant values of 50-130 pmol/l, and maximal binding sites (Bmax of 77-6100 sites/cell on receptor binding assays. Short term culture with recombinant human G-CSF induced myeloid differentiation (a two to three-fold increase in CD33 and CD15 expression), and a moderate 3H-thymidine uptake (stimulation index, 1.75) only in the GR-ST clone no. 15 which expressed a high number of G-CSF receptors (Bmax, 6100 sites/cell). Our data show that (a) exogenous expression of the G-CSF receptor and G-CSF stimulation can induce myeloid characteristics on ALL cells; and (b) in the G-CSF receptor-expressing cells, there is a correlation between the number of G-CSF receptors and cell responsiveness to G-CSF in either proliferation or differentiation.

Burkitt Lymphoma↗
PubMed1995

Determination of tetrahydro-beta-carbolines in rat brain by gas chromatography-negative-ion chemical ionization mass spectrometry without interference from artifactual formation.

This paper describes a quantitative method for neuroactive alkaloids, 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) and 1,2,3,4-tetrahydro-beta-carboline (TBC), in rat brain by gas chromatography-negative-ion chemical ionization mass spectrometry (GC-NICIMS). After addition of tetradeuterated MTBC and TBC (internal standards), the samples were subjected to deproteinization, reaction with fluorescamine, solvent extractions, trifluoroacetylation and GC-NICIMS analysis. In contrast to the other previous methods, the artifactual formation during analysis did not interfere with the determination of MTBC and TBC because their precursor tryptamine was removed as a fluorescamine derivative from the analytical system at the first step of pretreatment. MTBC and TBC were specifically and reliably determined in the range of pg-ng/sample. Application of the proposed method has revealed that the MTBC and TBC contents in rat brain significantly increase after intraperitoneal administration of MTBC and TBC, indicating their ability to easily cross the blood-brain barrier.

Animals↗
PubMed1995

Exogenously expressed granulocyte colony-stimulating factor (G-CSF) receptor on K562 cells can transduce G-CSF-triggered growth and differentiation signals.

Human granulocyte colony-stimulating factor (G-CSF) receptor cDNA was introduced into the erythroleukemic cell line K562, which normally does not express the receptor, using lipofection transfection of a G-CSF receptor expression plasmid vector. Transfected cells expressed the receptor with a dissociation constant of 130 pmol/L, and a maximum of 11,800 binding sites per cell. Culture of G-CSF receptor-expressing cells (GR-K562) in the presence of G-CSF enhanced DNA synthesis and a stimulation index of 4.61 was obtained in a 3H-thymidine uptake assay. Furthermore, flow cytometric studies revealed induced expression of CD11b (29% from 7%), and enhanced expression of CD13 (57% from 27%) on GR-K562 cultured in the presence of G-CSF. Our findings indicate that the exogenously expressed G-CSF receptor can deliver signals and function efficiently on these immature cells on which the receptor is not normally expressed, which suggests the presence of intact intracellular signal transduction pathways that can be used by the ectopically expressed receptor.

Cell Differentiation↗