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Biomedical subjects

N Takakura

Publications and source records attributed to N Takakura.

At least 73 records · Page 4Linked to original sources
PubMed1996

Vibration-induced finger flexion reflex and inhibitory effect of acupuncture on this reflex in cervical spinal cord injury patients.

The vibration-induced finger flexion reflex (VFR) and the inhibitory effect of acupuncture on this reflex were studied in five cervical spinal cord injury patients (C-SCIs). VFR, which is a tonic finger flexion reflex induced by vibratory stimulation on the finger tip, was induced before and after acupuncture was carried out on the same hand. A stainless steel needle was inserted to the Hoku point. As in healthy subjects, VFR was performed and it was significantly inhibited by acupuncture in the C-SCIs; mean maximum VFR was 204.2 +/- S.E. 68.6 g before and 119.8 +/- S.E. 42.2 g after acupuncture. The present results suggest that at least part of the reflex center for VFR is located in the spinal cord and that part of VFR inhibition by acupuncture may be mediated via the spinal cord.

Acupuncture Therapy↗
PubMed1996

PDGF mediates a neuron-astrocyte interaction in the developing retina.

Astrocytes invade the developing retina from the optic nerve head, over the axons of retinal ganglion cells (RGCs). RGCs express the platelet-derived growth factor A-chain (PDGF-A) and retinal astrocytes the PDGF alpha-receptor (PDGFR alpha), suggesting that PDGF mediates a paracrine interaction between these cells. To test this, we inhibited PDGF signaling in the eye with a neutralizing anti-PDGFR alpha antibody or a soluble extracellular fragment of PDGFR alpha. These treatments inhibited development of the astrocyte network. We also generated transgenic mice that overexpress PDGF-A in RGCs. This resulted in hyperproliferation of astrocytes, which in turn induced excessive vasculogenesis. Thus, PDGF appears to be a link in the chain of cell-cell interactions responsible for matching numbers of neurons, astrocytes, and blood vessels during retinal development.

Animals↗
PubMed1996

Involvement of platelet-derived growth factor receptor-alpha in hair canal formation.

Hair follicles develop and are maintained by multiple rounds of inductive events involving interactions among various cell types within the follicles and the adjacent mesenchyme. Although evidence suggests that several growth factors, cell adhesion molecules, and transcriptional regulators are involved in those cell-cell interactions, the molecular mechanisms regulating each pivotal step of hair follicle development, such as formation of the hair germ, root sheath, sebaceous gland, and hair canal, remain largely unknown. In this study, we established the antagonistic monoclonal antibody APA5 against platelet-derived growth factor (PDGF) receptor-alpha (PDGFR-alpha) and used it to investigate the role of PDGFR-alpha in neonatal skin development. In addition to the dermal mesenchyme, a known site of PDGFR-alpha expression, immunohistologic staining of neonatal skin detected transient expression of PDGFR-alpha in the perinatal epidermis for several days. On the other hand, ligands for PDGFR-alpha were detected in epithelial cells and sebaceous glands of hair follicles. To determine whether this contiguous expression of PDGF and PDGFR-alpha in neonatal skin plays a functional role, we injected APA5 into neonates to block the function of PDGFR-alpha. Consistent with the PDGF/PDGFR-alpha expression in the neonatal skin, two defects were induced by this procedure. First, hair canal formation in the epidermis was severely suppressed. Second, the growth of dermal connective tissues and of hair follicles of pelage hairs was suppressed. These results indicate that PDGF signals are involved in both the epidermis-follicle interaction and the dermal mesenchyme-follicle interaction required for hair canal formation and the growth of the dermal mesenchyme, respectively.

3T3 Cells↗
PubMed1995

Effect of acupuncture at the Hoku point on vibration-induced finger flexion reflex in man: comparison between press needle technique, electroacupuncture, and in-situ technique.

Effects of press needle technique (PN), electroacupuncture (EA), or in-situ technique (IS) on vibration-induced finger flexion reflex (VFR) were examined in 31 healthy adults. VFR, which is tonic finger flexion evoked by vibration applied to the finger tip, was induced by vibrating the volar side of the middle finger tip before and after acupuncture. Acupuncture was applied to the Hoku point on both sides. The three techniques, each studied on separate days, inhibited VFR and there was no significant difference in VFR inhibition among the three techniques (percentage of pre-acupuncture VFR was 71.5 +/- SE 2.2% after PN, 72.6 +/- SE 2.4% after EA, and 75.6 +/- SE 2.8% after IS). The results suggest that afferent signals from muscles contracting due to electrical stimulation had no significant effect on the reflex arcs of VFR; and that the intradermal stimulation by acupuncture played a significant role in VFR inhibition.

Acupuncture Therapy↗
PubMed1994

Stromal cell-dependent bone marrow culture with a nearly protein-free defined medium.

We examined the ability of a defined medium mSFO2 to support stromal cell-dependent B lymphopoiesis and myelopoiesis. Both ST2 and PA6 stromal cell lines were able to form monolayers in the presence of mSFO2 alone. While the ST2 monolayer could last for long period of time, either bFGF or EGF were required for the maintenance of the PA6 monolayer with mSFO2. mSFO2 did support the generation of distinct stages of B precursors on the ST2 layer and this culture condition was efficient enough to be used for limiting dilution assay of in vitro clonable B progenitors. While ST2 cell line failed to support long-term myelopoiesis with mSFO2, PA6 in combination of bFGF was able to support sustained generation of various hematopoietic progenitors. Indeed, 20 times increase of IL-3 reactive colony-forming cells was induced upon culturing the normal bone marrow cells on the PA6 layer for 8 days with mSFO2. Because total protein concentration of mSFO2 is only 10 micrograms/ml consisting of transferrin and insulin, the present result that mSFO2 is able to support the proliferation of normal hematopoietic progenitor cells would make an important step towards the standardization of bone marrow culture.

Animals↗
PubMed1994

PRAD1 gene over-expression in mantle-cell lymphoma but not in other low-grade B-cell lymphomas, including extranodal lymphoma.

Employing Northern blot analysis and the polymerase chain reaction, we investigated PRAD1 gene overexpression in the tumour tissues of 58 patients with B-cell lymphoma. These findings were then examined in relation to the patients' clinical and immunohistological characteristics. The over-expression of this gene was detected in 6/8 patients with mantle cell lymphoma (MCL) and in only 1/50 other lymphomas, indicating its close association with MCL. The patients with MCL had common clinical findings of advanced disease with generalized lymphadenopathy on admission, and they had a CD5+CD10-IgD+ phenotype. The patients with chronic lymphocytic leukaemia (CLL) also showed findings indicating a distinctive disease entity: a CD5+CD10-IgD+ phenotype and lack of PRAD1 over-expression. In contrast, most patients with diffuse low-grade lymphoma other than MCL and CLL had localized extranodal disease, expressed a CD5-CD10-IgD- phenotype, and lacked PRAD1 over-expression. These findings suggest that extranodal low-grade lymphomas differ from nodal MCL and are not part of the spectrum of CLL.

Base Sequence↗
PubMed1993

Expression of MDR1 gene in acute leukemia cells: association with CD7+ acute myeloblastic leukemia/acute lymphoblastic leukemia.

MDR1 gene expression was examined in acute leukemia cells from 75 Japanese patients at diagnosis (50 with acute myeloblastic leukemia [AML]: 10 M1, 18 M2, 5 M3, 8 M4, 9 M5; 25 with acute lymphoblastic leukemia [ALL]: 13 B-precursor, 12 T-lineage). The results of MDR1 mRNA expression by reverse transcriptase polymerase chain reaction were confirmed by immunostaining using the anti-P-glycoprotein monoclonal antibody UIC2 and by a functional study using the rhodamine efflux test. Morphologically, AML M1 cases had the highest incidence of MDR1 gene expression (6 of 10 patients). Phenotypically, CD7 and CD34 were the only surface markers that were significantly associated with MDR1 gene expression (P < .01). In CD7+CD4-CD8- ALL, which is thought to originate from the lymphohematopoietic stem cell, expressed the MDR1 gene with a high incidence (six of eight patients), whereas three surface CD3+ and one CD4+CD8+ T-cell ALL (T-ALL) did not have detectable MDR1 transcripts. Only two cases of 13 B-precursor ALL had MDR1 mRNA, one of which had the Philadelphia (Ph1) chromosome. No association was observed between MDR1 gene expression and CD34 positivity in ALL. Our results that MDR1 mRNA was frequently expressed in CD7+ AML and CD7+CD4-CD8- ALL, together with the previous reports indicating clinical similarities between these leukemias, provides a clue to clarify a relationship between CD7+ AML and CD7+CD4-CD8- ALL. In addition, MDR1 expression in CD7+ AML/ALL might be responsible for the poor response to conventional chemotherapies of these types of leukemia.

Adult↗
PubMed1993

Effect of acupuncture at the right Hoku point on bilateral vibration-induced finger flexion reflex in man: comparison between in-situ and Sparrow Pecking technique.

The purpose of this study was to compare the effect of the Sparrow Pecking (SP) technique with that of the In-Situ (IS) technique of acupuncture on vibration-induced finger flexion reflex (VFR). Subjects were 30 healthy adults. VFR, flexion movement of the vibrated finger, was induced by vibrating the volar side of the middle finger tip. The acupuncture point was the right Hoku point. Both techniques of acupuncture inhibited VFR in the ipsilateral and contralateral sides, but inhibition with SP was significantly greater than that with IS (percentage control force of VFR, mean +/- SD: with SP right, 62.1 +/- 24.6%, left, 60.6 +/- 27.9%, with IS right, 74.9 +/- 26.6%, left, 78.1 +/- 29.5%, P < 0.0005). The results suggest that SP suppresses facilitation of VFR in the reflex arcs more than IS does.

Acupuncture Points↗
PubMed1993

Frequent gene expression of granulocyte colony-stimulating factor (G-CSF) receptor in CD7+ surface CD3- acute lymphoblastic leukaemia.

Gene expression of various cytokine receptors in CD7+ acute lymphoblastic leukemia (ALL) cells in relation to responsiveness to these cytokines was examined by reverse transcription polymerase chain reaction and Northern blot studies. Leukemic cells from all of seven CD7+ ALL patients examined fulfilled the criteria for ALL according to the FAB classification; surface CD3 was absent in all of these patients, while cytoplasmic CD3 and/or CD3 epsilon mRNA were found in all of them. Samples from six of the seven patients at initial disease expressed the granulocyte colony-stimulating factor receptor (G-CSFR) gene. Leukemic cells with G-CSFR transcripts from one patient at initial disease showed growth response to G-CSF in vitro, and those from two other patients became responsive to G-CSF at relapse. Neither in vitro nor in vivo myeloid differentiation was observed in any samples that responded to G-CSF. Interleukin 3R alpha (IL-3R alpha) gene was expressed in samples from one patient at initial disease and from two patients at relapse. GM-CSFR beta gene mRNA was detected in two patients with IL-3R alpha mRNA. Our results show that the leukemic cells in these CD7+ ALL patients frequently expressed G-CSFR as a functional property, thus calling attention to the appropriate clinical application of G-CSF for ALL patients.

Adolescent↗
PubMed1992

Phenotypical characteristics of acute myelocytic leukemia associated with the t(8;21)(q22;q22) chromosomal abnormality: frequent expression of immature B-cell antigen CD19 together with stem cell antigen CD34.

Twenty-three acute myelocytic leukemia (AML) patients with t(8;21) chromosomal abnormality, all classified as M2 (French-American-British [FAB] classification), were investigated. Blastic cells from all patients were positive for the stem cell-associated antigens, CD34 and HLA-DR, and the immature myeloid antigens, CD13 and CD33. The nonblastic leukemic cells expressed the more mature myeloid antigens, CD11b and CD15, with loss of the immature phenotype. The incidence of positivities for the stem cell-associated antigens, CD34 and HLA-DR, in t(8;21) AML cells was significantly higher in comparison with those in other AML showing granulocytic differentiation (M2 or M3). AML cells with t(8;21) also showed some phenotypic abnormalities. Frequent expression of CD19 was found in the blastic population of t(8;21) AML (18 of 23 cases) without other B-cell antigens and Ig gene rearrangements. CD19 expression was confirmed by immunocytochemistry and Northern blotting. The CD19+ blastic cells coexpressed both CD34 and HLA-DR. In addition, CD33+ cells among the blastic fraction in t(8;21) AML cells were fewer in number than in those of M2 or M3 AML without t(8;21). Our findings indicate that leukemic blasts of t(8;21) AML commonly express CD19 while preserving the stem cell-associated antigens, and differentiate into the granulocytic pathway with discordant maturation such as low CD33 expression.

Adult↗
PubMed1992

Structural alterations of the p53 gene in human leukemias.

We have investigated alterations of the p53 gene in human leukemias by polymerase chain reaction-mediated restriction fragment length polymorphism analysis. This method detects the codon 72 polymorphism of the p53 gene, allowing identification of loss of heterozygosity (LOH) of the p53 gene. In this study, at least two specimens were obtained from each patient to compare the allele status at different points of clinical course. Of 21 cases examined 7 were heterozygous at this polymorphic site and were evaluable for LOH study. Only one patient of Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL) lost the heterozygosity in the specimen of her last relapse. Leukemic cells from her repeated relapses including the last one revealed to have the clonally rearranged immunoglobulin H chain gene of the same size, indicating that alteration of the p53 gene in this patient might account for the lethal relapse as a clonal evolution event. Northern-blot analysis of the p53 gene showed that one case of CD7(+) ALL had altered p53 mRNA. Overall, it is demonstrated that alterations of the p53 gene might be involved in the pathogenesis or progression of at least some human leukemias, although the alterations in leukemias seemed to be not as frequent as in solid tumors.

Base Sequence↗
PubMed1992

Effect of acupuncture at right Hoku point on the bilateral vibration-induced finger flexion reflex in man.

Vibration applied to the volar side of the finger tip has been reported to induce finger flexion reflex. Acupuncture is reported to inhibit this vibration-induced finger flexion reflex (VFR) in the ipsilateral hand. The purpose of this study was to investigate the effect of unilateral acupuncture in the hand on VFR in both hands. As no systematic study on the relationship between VFR and the force of voluntary contraction with no vibration (Initial Force: IF) has been reported, this relationship was studied prior to the present study on acupuncture. VFR was induced by mechanical vibration on the volar side of the middle finger tip with 10 g to 500 g IF. With approximately 300 g IF, VFR was consistent. Therefore, approximately 300 g IF was applied for VFR induction to study the effect of acupuncture on VFR. A stainless steel needle was inserted into the right Hoku point and remained inserted (in-situ technique) for 10 minutes. VFR in both hands was significantly decreased by acupuncture at the right Hoku point (% control force of VFR: right, 67.8%; left, 74.6%). The present results suggest that acupuncture in the unilateral hand influences the bilateral reflex arc of VFR.

Acupuncture Points↗
PubMed1991

Block resection of the hepatoduodenal ligament for carcinoma of the bile duct and gallbladder. Surgical technique and a report of 11 cases.

Carcinoma of the bile duct and gallbladder often infiltrates the entire hepatoduodenal ligament. Therefore radical resection should include block resection of the hepatoduodenal ligament. Over the last two years, block resection of the hepatoduodenal ligament for carcinoma of the bile duct and gallbladder was performed in 11 patients. When the carcinoma was located in the hilar bile duct, a combination of hemihepatectomy including the caudate lobe and ligamentetomy, "hepato-ligamentectomy", was performed (six cases). When the carcinoma was in the lower bile duct, a combination of pancreatico-duodenectomy and ligamentectomy, "ligamento-pancreatectomy", was performed (three cases). In two extremely advanced cases a combination of both hepatectomy and pancreatectomy with ligamentectomy, "hepato-ligamento-pancreatectomy", was performed. To accomplish these procedures safely, double catheter bypass of the portal circulation, devised by the authors in 1986, proved very effective in maintaining sufficient hepatic circulation and preventing portal congestion during block resection of the hepatoduodenal ligament. Histological evidence of invasion of the carcinoma cells into the hepatoduodenal ligament was detected in 10 cases, and in half of them the hepatic artery or portal vein was involved. As of April 1988, five cases in whom curative resection was performed are still alive, the longest survival period being 18 months. Four cases died in the early postoperative period, three of the deaths being due to sepsis and one to respirator malfunction.

Adenoma, Bile Duct↗
PubMed1988

Radical block resection of hepatoduodenal ligament for carcinoma of the bile duct with double catheter bypass for portal circulation.

A new concept of radical block resection of the hepatoduodenal ligament for carcinoma of the bile duct and new double bypass technique of portal circulation for the procedure were introduced. Clinical experiences of six patients were reported. By combined use of radical block resection of the hepatoduodenal ligament and double bypass technique, the radical resectability of carcinoma of the bile duct became a reality, and improvement of postoperative survival rate is expected.

Biliary Tract Neoplasms↗
PubMed1987

[A case of alpha-fetoprotein, carcinoembryonic antigen and human chorionic gonadotropin producing renal cell carcinoma].

A 51-year-old woman was admitted with a complaint of a left hypochondralgia and an abdominal mass. Laboratory testing showed a markedly increased alpha-fetoprotein (AFP) level (234,700 ng/ml). The enlargement of the left kidney and the adrenal gland was noted by CT scan and a tumorous thrombus was shown by inferior caval venography. The patient underwent a left nephrectomy, a combined resection of the spleen, tail of the pancreas and the removal of a tumorous caval thrombus. The patients AFP level gradually decreased after surgery. In a histological study, the tumor was diagnosed as a renal cell carcinoma and the presence of AFP, CEA, and HCG in the cancer cells was demonstrate by means of the "PAP" method.

Biomarkers, Tumor↗
PubMed1985

[Treatment of small liver cancer].

Histopathological studies were conducted on the resected lesions in eight cases of small liver cancer, and therapeutic methods are discussed. Examinations revealed tumor cell infiltration into the fibrous capsule in 5/7 (71%), into extracapsular tissues in 3/7 (43%), and vascular invasion by tumor cells in 2/8 (25%) cases. Seven patients were complicated with liver cirrhosis and one patient with hepatic fibrosis. On the basis of preoperative TAE performed in three cases and studies on the resected indicating that tumor cells remained that have infiltrated into extracapsular areas, resection was considered to be necessary to attain radical cure. At 100%, the one-year survival rate was encouraging. However, two cases of recurrence would suggest that further studies are necessary on areas to be resected.

Aged↗