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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 469 records · Page 26Linked to original sources
PubMed1995

Accumulation of immature CD3-CD4+CD8- single-positive cells that lack CD69 in epithelial cell tumors of the human thymus.

Human thymomas are epithelial tumors that are associated with a large number of nonneoplastic T cells of mainly immature phenotype, suggesting that epithelial cells of thymomas retain the function of thymic cortical epithelium. We report here that a large proportion (16-85%, mean +/- SD 58 +/- 22%, n = 17) of CD4+ single-positive T cells within the thymoma lack cell surface expression of CD3 and also of CD69, an early activation antigen that is expressed by positively selected thymocytes. Normal thymus had this CD4+CD8-CD3- population at much lower levels (12 +/- 7%, n = 11). It has been reported that in the human the CD4+CD8-CD3- cells are the predominant population that is intermediate between the CD4-CD8- double-negative and CD4+CD8+ double-positive stages. In contrast to CD4+ single-positive cells, most of the CD8+ single-positive cells in the thymoma as well as in the normal thymus expressed CD69 and a high level of CD3. A partial explanation of these observations is that the epithelial cells of thymoma were unable to positively select all the immature thymocytes generated in the thymoma. This relative inefficiency of positive selection could not be attributed solely to the paucity of MHC class II expression in the thymoma.

Antigens, CD↗
PubMed1995

Mussel adhesive plaque protein gene is a novel member of epidermal growth factor-like gene family.

A mussel (Mytilus galloprovincialis) cDNA encoding Mgfp2, a major component of the adhesive plaque that anchors mussels tightly to underwater surfaces was isolated. It encoded a protein mainly consisted of epidermal growth factor-like repeats, containing tyrosine residues that will be converted to 3,4-dihydroxyphenylalanine near C and N termini. Amino acid residues important for cell-cell interaction in other epidermal growth factor-like proteins were, however, not conserved in the structure of Mgfp2. RNA blot analysis on adult tissues showed foot-specific expression of this gene, while the analysis on developing larvae showed that the expression starts with formation of the foot. These results suggest that the function of Mgfp2 has been specialized to form the adhesive plaque.

Amino Acid Sequence↗
PubMed1995

pp60c-src expression in rat spermatogenesis.

A fractionation of the membrane extract of rat testes revealed the existence of pp60c-src kinase activity. The expression of pp60c-src was examined in the developing rat testes. The immunecomplex kinase assay using a monoclonal antibody specific to pp60c-src (mAb327) showed that the expression of pp60c-src kinase activity increased during the development of rat testes and declined in the adult. The increase in pp60c-src kinase activity observed during the development of rat testes was accompanied with an increase in the amount of pp60c-src protein. The peak period in the increase of pp60c-src kinase activity well coincided with the timing, when the spermatogenesis by meiosis just began. The immunohistochemical staining of pp60c-src in rat testes demonstrated that pp60c-src is most abundantly expressed in the spermatids which are the spermatogenic cells in the post-meiotic phase of the spermatogenesis. These findings strongly suggest that pp60c-src is a developmentally regulated gene product which is involved in rat spermatogenesis.

Amino Acid Sequence↗
PubMed1995

Lymph node metastases in carcinoma of the head of the pancreas region.

Histopathological examination of lymph node metastatic involvement in 139 specimens obtained from patients who underwent pancreatoduodenectomy or total pancreatectomy combined with wide resection of lymph nodes was performed, to clarify the critical areas of lymph node dissection in patients with carcinoma of the head of the pancreas region. Perigastric lymph node involvement in patients with carcinoma of the head of the pancreas was 14 per cent, in those with carcinoma of the distal bile duct 0 per cent and in those with carcinoma of the papilla of Vater 4 per cent. Para-aortic lymph node involvement in patients with carcinoma of the head of the pancreas, the distal bile duct and the papilla of Vater was 26, 9 and 0 per cent, respectively. On the basis of these results, pylorus-preserving pancreatoduodenectomy is indicated in almost all patients with carcinoma of the distal bile duct and the papilla of Vater. In patients with carcinoma of the head of the pancreas, however, wide dissection of lymph nodes, including para-aortic lymph nodes, should be carried out because of the relatively high incidence of para-aortic lymph node involvement.

Carcinoma, Ductal, Breast↗
PubMed1995

Relationship between actions of transforming growth factor (TGF)-beta and cell surface expression of its receptors in clonal osteoblastic cells.

Various osteoblastic cell lines were examined for the relationship between the presence of cell-surface transforming growth factor (TGF)-beta receptors and the synthesis of matrix proteins with their responsiveness to TGF-beta. Treatment with TGF-beta 1 inhibited proliferation and stimulated proteoglycan and fibronectin synthesis in MC3T3-E1 and MG 63 cells. The major proteoglycans synthesized by these cells were decorin and biglycan, and TGF-beta 1 markedly stimulated the synthesis of decorin in MC3T3-E1 and of biglycan in MG 63 cells. SaOS 2 and UMR 106 cells synthesized barely detectable amounts of decorin or biglycan, and TGF-beta 1 did not stimulate the synthesis of these proteoglycans. In SaOS 2 cells, however, TGF-beta 1 enhanced fibronectin synthesis. TGF-beta 1 did not show any of these effects in UMR 106 cells. Receptor cross-linking studies revealed that only MC3T3-E1 and MG 63 cells had both types I and II signal-transducing receptors for TGF-beta in addition to betaglycan. SaOS 2 cells possessed type I but no type II receptor on the cell surface. In contrast, SaOS 2 as well as MC3T3-E1 and MG 63 cells expressed type II receptor mRNA by Northern blot analysis, and cell lysates contained type II receptor by Western blot analysis. Thus, it appears that type II receptor present in SaOS 2 cells is not able to bind TGF-beta 1 under these conditions. UMR 106 cells with no response to TGF-beta 1 had neither of the signal-transducing receptors by any of the analyses. These observations using clonal osteoblastic cell lines demonstrate that the ability of osteoblastic cells to synthesize bone matrix proteoglycans is associated with the responsiveness of these cells to TGF-beta 1, that the responsiveness of osteoblastic cells to TGF-beta 1 in cell proliferation and proteoglycan synthesis correlates with the presence of both types I and II receptors, and that the effect of TGF-beta 1 on fibronectin synthesis can develop with little binding of TGF-beta 1 to type II receptor if type I receptor is present. It is suggested that the combination of cell-surface receptors for TGF-beta determines the responsiveness of osteoblastic cells to TGF-beta and that changes in cell-surface TGF-beta receptors may play a role in the regulation of matrix protein synthesis and bone formation in osteoblasts.

Animals↗
PubMed1995

Intraoperative peritoneal washing cytology with the rapid immunoperoxidase method using microwave irradiation.

The rapid immunocytochemical staining of gastrointestinal cancer-associated antigens, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), for intraoperative peritoneal washing cytology of pancreatic or biliary carcinoma can be completed in only 25 minutes by using microwave irradiation to accelerate incubation of the primary antibody. Only 3-second irradiation at 500 W for fresh smears produced specific antigen staining of malignant cells similar to that obtained with longer incubation, and the sensitivity of intraoperative cytology was greater than by the conventional staining method. The rapid immunocytochemical staining method of peritoneal washings at laparotomy can provide sensitive information for determining more aggressive therapy for intraperitoneal spread of malignant cells before closing the abdominal wall.

Aged↗
PubMed1995

Role of endogenous nitric oxide in ischemia-reperfusion injury in rat liver.

Evidence has accumulated that oxygen-derived free radicals contribute to the cellular damage induced by ischemia-reperfusion. It has been suggested that nitric oxide (NO) may act as a protective factor in ischemia-reperfusion injury since NO increases blood flow and may scavenge oxyradicals. Nevertheless, controversy exists as to the role of NO. This study was designed to clarify the role of endogenous NO in ischemia-reperfusion-induced liver injury in rats in vivo. Wistar rats weighing 250-300 g were divided into three groups: (1) untreated group (Control); (2) NG-nitro-L-arginine, a specific inhibitor of NO production (L-NNA); and (3) L-arginine-pretreated L-NNA group (AR+L-NNA). Occlusion of all vessels to the median and left hepatic lobes (60 min) was followed by reperfusion for 1 or 24 hr. L-NNA was administered before ischemia as a 10 mg/kg bolus. L-Arginine was given just before L-NNA administration as a 100 mg/kg bolus. Administration of L-NNA resulted in endothelial cell injury characterized by the elevation of serum hyaluronic acid as well as the reduction of hepatic tissue blood flow, and the recovery of hepatic adenosine triphosphate was depressed compared with the control after both 1 and 24 hr of reperfusion. Furthermore, the leakages of various liver enzymes and lipid peroxide were also increased, associated with histological damage. This effect of L-NNA was completely abolished by pretreatment with L-arginine. These results suggest that endogenous NO provides a protective effect against ischemia-reperfusion injury in rat liver.

Adenine Nucleotides↗
PubMed1995

Characterization of two integral membrane proteins located in the protein bodies of pumpkin seeds.

Two integral membrane proteins, MP28 and MP23, were found in protein bodies isolated from pumpkin (Cucurbita sp.) seeds. Molecular characterization revealed that both MP28 and MP23 belong to the seed TIP (tonoplast intrinsic protein) subfamily. The predicted 29 kDa precursor to includes six putative membrane-spanning domains, and the loop between the first and second transmembrane domains is larger than that of MP28. The N-terminal sequence of the mature MP23 starts from residue 66 in the first loop, indicating that an N-terminal 7 kDa fragment that contains one transmembrane domain is post-translationally removed. During maturation of pumpkin seeds, mRNAs for MP28 and MP23 became detectable in cotyledons at the early stage, and their levels increased slightly until a rapid decrease occurred at the late stage. This is consistent with the accumulation of the 29 kDa precursor and MP28 in the cotyledons at the early stage. By contrast, MP23 appeared at the late stage simultaneously with the disappearance of the 29 kDa precursor. Thus, it seems possible that the conversion of the 29 kDa precursor to the mature MP23 might occur in the vacuoles after the middle stage of seed maturation. Both proteins were localized immunocytochemically on the membranes of the vacuoles at the middle stage and the protein bodies at the late stage. These results suggest that both MP28 and the precursor to MP23 accumulate on vacuolar membranes before the deposition of storage proteins, and then the precursor is converted to the mature MP23 at the late stage. These two TIPs might have a specific function during the maturation of pumpkin seeds.

Amino Acid Sequence↗
PubMed1995

Global stability of an SIR epidemic model with time delays.

An SIR disease transmission model is formulated under the assumption that the force of infection at the present time depends on the number of infectives at the past. It is shown that a disease free equilibrium point is globally stable if no endemic equilibrium point exists. Further the endemic point (if it exists) is globally stable with respect to the whole state space except the neighborhood of the disease free state.

Animals↗
PubMed1995

Effects of hypergravity on the elongation growth in radish and cucumber hypocotyls.

The elongation growth of the hypocotyls of radish and cucumber seedlings was examined under hypergravity in a newly developed centrifuge (Kasahara et al. 1995). The effects of hypergravity on elongation growth differed between the two species. The rate of elongation of radish hypocotyls was reduced under basipetal hypergravity (H+2O g) but not under acropetal hypergravity (H-13 g), as compared to growth under the control conditions (C+1 g and C-1 g). In cucumber hypocotyls, elongation growth was inhibited not only by basipetal but also by acropetal hypergravity. Under these conditions, the reduction in the elongation growth of both radish and cucumber hypocotyls was accompanied by an increase in their thickness. Although no distinct differences in relative composition of neutral sugars were found, the amounts of cell-wall components (pectic substances, hemicelluloses and cellulose) per unit length of hypocotyls were increased by exposure to hypergravity.

Brassicaceae↗
PubMed1995

Toluene induces behavioral activation without affecting striatal dopamine metabolism in the rat: behavioral and microdialysis studies.

We examined the effects of toluene on the release of dopamine (DA) and its metabolites in rat striatum using microdialysis. Intraperitoneal injection of 800 mg/kg toluene significantly increased motor activity in rats, as did methamphetamine (MAP) (1 mg/kg). However, 800 mg/kg toluene did not affect the extracellular levels of DA, 3,4-dihydroxyphenylacetic acid, homovanillic acid, or 5-hydroxyindoleacetic acid. This is in contrast to MAP, which significantly increased extracellular DA and decreased the extracellular levels of its metabolites. These results suggest that toluene-induced behavioral augmentation may not be associated with alterations in DA or serotonin neurochemistry such as are associated with MAP-induced behavioral augmentation.

Animals↗
PubMed1995

A quantitative study of the effects of prenatal X-irradiation on the development of cerebral cortex in rats.

Pregnant rats were exposed to a single whole body X-irradiation on day 15 of gestation at a dose of 1.0 Gy. The offspring showed microcephaly at 7 weeks of age. Their body weight, brain weight, cortical thickness and the numerical density of neurons and synapses in the somatosensory and visual cortex were examined. Significant decreases in cortical thickness in both somatosensory (25%) and visual (16%) cortex were observed. However, there were no significant changes in the numerical density of neurons and synapses, nor in synapse-to-neuron ratios in both cortical regions between control and X-irradiated groups. These results suggest that prenatal X-irradiation can decrease the number of neurons, and the neurons which survive X-irradiation proliferate and elaborate connections in a normal fashion. This is in contrast to the animals exposed to ochratoxin A, in which numerical density of neurons in the somatosensory cortex is increased, with normal numerical density of synapses, resulting in low synapse-to-neuron ratios. The discrepancy in the synapse-to-neuron ratios between the X-irradiation and ochratoxin A-treatment might derive from a different effect on the developing neurons.

Animals↗
PubMed1995

Detection of measles virus genome directly from clinical samples by reverse transcriptase-polymerase chain reaction and genetic variability.

A simple and sensitive method for the detection of measles virus genome was developed, amplifying the regions encoding the nucleocapsid (N) protein and hemagglutinin (H) protein of measles virus by reverse transcriptase-polymerase chain reaction (RT-PCR). We examined a variety of measles patients: 28 patients with natural infection, 4 with measles encephalitis and 1 with subacute sclerosing panencephalitis (SSPE). In 28 patients with natural measles infection a single step PCR amplifying the N region resulted in a high detection rate for all plasma samples (28/28) within 3 days of the onset of rash and 80% (20/25) even on day 7 of the onset of rash and later. Within 3 days of the onset of rash, 24/25 (96.0%) of nasopharyngeal secretions (NPS) and 27/28 (96.4%) of peripheral blood mononuclear cells (PBMC) were positive for the N region PCR and the positivity rate of PCR decreased in NPS and PBMC after 7 days of the rash. In acute measles infection, measles genome was detected in all cell fractions, CD4, CD8, B cells, and monocytes/macrophages by the H gene nested PCR. Measles genome was also detected from cerebrospinal fluids (CSF) in patients with measles encephalitis, SSPE, and acute measles by the H gene nested PCR. PCR products of the N and H regions were sequenced and we confirmed the presence of measles genome. Based on the sequence data, chronological sequence differences were observed over the past 10 years. The sequences obtained from the SSPE patient were closely related to those of the wild viruses that were circulating at the time when the patient initially acquired measles. RT-PCR for NPS, PBMC, CSF, and plasma provides a useful method for the diagnosis of measles and molecular epidemiological study in addition to virus isolation.

Adolescent↗
PubMed1995

Thyrotropin-releasing hormone in treatment of intractable epilepsy: neurochemical analysis of CSF monoamine metabolites.

The efficacy of thyrotropin-releasing hormone in children with intractable epilepsy was investigated and changes in cerebrospinal fluid monoamine metabolites were analyzed. The 18 patients had either West syndrome (12 patients) or Lennox-Gastaut syndrome (6 patients), which was intractable to antiepileptic drug therapy and to adrenocorticotrophic hormone. Thyrotropin-releasing hormone-tartrate was administered for 4 weeks. Before and after the thyrotropin-releasing hormone administration, cerebrospinal fluid was collected and analyzed for 5-hydroxyindoleacetic acid, kynurenine, homovanillic acid, and 3-methoxy-4-hydroxyphenyl glycol. The patients were classified into 3 groups, based on seizure frequency and electroencephalographic effects: cessation of seizures and seizure discharges (very effective; group A), reduction of seizures and/or seizure discharges (effective; group B), and no changes in frequency of seizures or discharges (not effective; group C). There were 6 patients in group A, 3 in group B, and 9 in group C. There were no significant differences in monoamine metabolites before and after the thyrotropin-releasing hormone therapy. A trial of thyrotropin-releasing hormone for the treatment of intractable epilepsy is warranted and further study is required on the mechanism of the antiepileptic action of thyrotropin-releasing hormone.

Child↗
PubMed1995

Anatomical study on valves of human facial veins.

The valves of the facial veins of 39 sides from 20 cadavers, aged 54-95 years, were investigated. Anatomical study of the valves is important, because the facial veins can be used for microvascular anastomosis in reconstruction in the head and neck. The present study confirmed that valves existed in the human facial veins, and were most frequently observed around the lower border of the mandible. When valves were classified into 5 types according to the morphology of the lobules, bicuspid valves were the most common (93.5%), followed by traced valves (4.1%), valve preparation (1.3%), and unicuspid valves (0.9%). However, no tricuspid valves were observed. Valves appeared most often (82.9%) at confluences with the facial veins. The length of valves in the trunk of the facial veins was twice the size of the inner diameter of the vessels in 78.4% of the cases. Therefore, when valves were observed at the anastomosis sites, the present results indicated that these valves could be avoided by resecting a length of about twice the inner diameter.

Aged↗
PubMed1995

Cloning, tissue distribution, and intrarenal localization of ClC chloride channels in human kidney.

Two kidney-specific chloride channels, ClC-K1 and ClC-K2, have been isolated from rat kidney. In the present study, we sought to isolate human homologue of rat ClC-K2 chloride channel that was present in the thick ascending limb of Henle's loop and collecting ducts. Human kidney cDNA library was screened with the whole rat ClC-K2 cDNA probe. Two highly homologous but not identical cDNAs were isolated and sequenced. Northern analysis showed that both clones were expressed only in kidney among various human tissues, demonstrating that kidney-specific ClC family members were also present in human kidney. Because both clones had almost the same nucleotide identity (approximately 80%) with rat ClC-K2, we could not determine by sequence alone which human clone corresponded to rat ClC-K2. Accordingly, we performed reverse transcription PCR using dissected human nephron segments and identified the site of expression of each clone in human nephron segments. One clone was only expressed in the thin limb of Henle's loop and the other was expressed in glomeruli, proximal tubules, and collecting ducts. We identified the latter clone as human ClC-K2 based on the localization of rat ClC-K1 and ClC-K2. Identification of human ClC-K2 clone will be of help in understanding the genetic involvement of chloride channel in disorders of chloride transport such as Bartter's syndrome.

Amino Acid Sequence↗
PubMed1995

Molecular characterization of proteins in protein-body membrane that disappear most rapidly during transformation of protein bodies into vacuoles.

During the post-germination growth of seeds, protein bodies fuse with one another and are converted to a central vacuole. To investigate this transition, protein-body membranes from dry seeds of pumpkin (Cucurbita sp.) were prepared and their protein components characterized. Five major proteins (designated MP23, MP27, MP28, MP32 and MP73) were detected in the protein-body membranes. A cDNA clone encoding both MP27 and MP32 has been isolated. The deduced precursor polypeptide was composed of a hydrophobic signal sequence, MP27 and MP32, in that order. A putative site of cleavage between MP27 and MP32 was located on the COOH-terminal side of asparagine 278, an indication that the post-translational cleavage may occur by the action of a vacuolar processing enzyme that converts proprotein precursors of seed proteins into the mature forms. Immunoelectron microscopic analysis showed that MP27 and MP32 were associated with protein-body membrane of dry pumpkin seeds. Among the five membrane proteins, MP27 and MP32 disappeared most rapidly during seedling growth. The degradation of MP27 and MP32 starts just after seed germination and proceeds in parallel with the transformation of the protein bodies into a vacuole.

Amino Acid Sequence↗