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Biomedical subjects

Y Takagi

Publications and source records attributed to Y Takagi.

At least 55 records · Page 3Linked to original sources
PubMed2001

Stimulation of non-specific immune functions in seawater-acclimated rainbow trout, Oncorhynchus mykiss, with reference to the role of growth hormone.

The influence of acclimation to seawater (SW) and growth hormone (GH) administration on immune functions was examined in the rainbow trout (Oncorhynchus mykiss). After 3 days acclimation to dilute SW (12 parts per thousand, ppt), an increase in plasma lysozyme activity was observed compared to the fish kept in fresh water (FW). No change was seen in plasma immunoglobulin M (IgM) levels. When they were transferred from dilute SW to full-strength SW (29 ppt) after a single intra-peritoneal injection of ovine or salmon GH, plasma sodium levels of GH-treated fish were significantly lower than those of the control fish injected with Ringer's solution 24 h after the transfer. The plasma level of IgM was not influenced by GH injection in the fish kept in FW nor in those transferred to SW. The administration of GH increased plasma lysozyme activity in the fish in FW, but no further increase was seen after SW transfer. The production of superoxide anions in peripheral blood leucocytes was stimulated by GH in both FW and SW. These results suggest that GH is involved in the stimulation of the non-specific immune functions in SW-acclimated salmonids.

Adaptation, Physiological↗
PubMed2001

Biotransformation of thujopsene by Caragana chamlagu.

Biotransformation of thujopsene (1) using a cell suspension culture of Caragana chamlagu for 14 days gave mayurone (2, 52%) and two new compounds, 3beta-hydroxy-4-thujopsene (4, 16%) and 3beta-epoxythujopsa-5beta-ol (3, 22%).

Biotransformation↗
PubMed2001

Cutaneous lymphomas in Tokyo: analysis of 62 cases in a dermatology clinic.

BACKGROUND: The epidemiology of cutaneous lymphomas revealed that the incidence of lymphomas differed depending on various factors including area, race, and sex, among others. OBJECTIVE: This study was undertaken to analyse the incidence of cutaneous lymphomas in Tokyo. METHODS: The clinical records and histologic material from 50 patients with lymphomas of the skin and 12 patients with lymphomatoid papulosis seen during the last 10 years at the Department of Dermatology, The Jikei University School of Medicine, Tokyo, have been reviewed. RESULTS: T-cell lymphomas including mycosis fungoides (MF)-Sézary's syndrome (SS) complex and adult T-cell leukemia/lymphoma (ATL) were more frequent than B-cell lymphomas. The incidence of ATL is associated with the number of human T-cell lymphotropic virus type 1 (HTLV-1) carriers in the general population. Cutaneous B-cell lymphoma (CBCL) is not as rare as previously thought in Japan. CONCLUSIONS: Although the frequency of these cases depends on many unrelated factors, these values can provide a rough indication of the incidence of cutaneous lymphomas in Tokyo. The incidence of cutaneous lymphomas may be influenced by changes in environmental factors including viral infections.

Adolescent↗
PubMed2001

Comparative study of self-expandable metallic stent and bypass surgery for inoperable esophageal cancer.

We evaluated the effect of two different therapies for 23 patients with inoperable esophageal cancer, of whom 13 patients underwent placement of a metallic stent and 10 received bypass surgery. We newly defined the improved level of food intake and the effective rate based on the grade of the patient's status in order to evaluate objectively. Although the effect of stent placement was significantly better than that of bypass surgery, there were no significant differences in the improved level of food intake and the effective rate between the two groups. Four out of 10 patients in the bypass group had suture insufficiency, resulting in no oral intake and a fatal outcome. In addition, the ratio of survival period of ability to ingest orally and in-hospital mortality was significantly favorable in the stent group compared with the bypass group. In conclusion, stent placement should be the first choice for inoperable malignant stenosis or esophageal fistula.

Adult↗
PubMed2001

Pulpal response to exposure with Er:YAG laser.

OBJECTIVE: The purpose of this study was to evaluate the pulpal response to the Er:YAG laser after accidental exposure of the pulp. STUDY DESIGN: Cavities were prepared, and pulps were exposed by either Er:YAG laser or mechanically by a slow-speed conventional handpiece (control group) in 76 maxillary first molars of male Wistar rats. Rats were killed immediately, at 3 days, 1 week, and 2 weeks. Histopathologic examinations of the pulp at the exposure site were performed and evaluated with the Mann-Whitney U test (P <.05). RESULTS: The Er:YAG laser group showed no bleeding and no dentin chips at the exposure site immediately after pulp exposure. However, they displayed an area of blood extravasation near the exposure site. Subsequently, the Er:YAG laser group formed dentin bridges at the exposure site more frequently than the control group. The Er:YAG laser group demonstrated more reparative dentin formation near the exposure site than the control group, especially at 2 weeks, which was highly significant (P <.01). CONCLUSION: According to the results of this study, Er:YAG laser-exposed pulp tissue demonstrated good healing capacity with the formation of a dentin bridge and reparative dentin. However, further investigations are suggested to study the effect of the blood extravasation, which appeared near the laser exposure sites.

Aluminum Silicates↗
PubMed2001

Expansion of megakaryocyte progenitors from cryopreserved leukocyte concentrates of human placental and umbilical cord blood in short-term liquid culture.

Long-term severe thrombocytopenia following human placental and umbilical cord blood (CB) transplantation is a significant clinical problem. We studied the ex vivo expansion of megakaryocytic progenitor cells (CFU-Meg) from cryopreserved/thawed leukocyte concentrates (LC) of CB prepared by the Tokyo Cord Blood Bank protocol. The LC cells were cultured in serum-free culture medium supplemented with a combination of early-acting cytokines including thrombopoietin (TPO), flt3-ligand (FL), and stem cell factor (SCF). Combination of TPO plus FL, TPO plus SCF, and all of these cytokines together resulted in 8.9-, 7.7-, and 8.4-fold increases in CFU-Meg, respectively, by Day 5 of culture. Our results showed that this simple expansion strategy has the potential for expanding CFU-Meg from cryopreserved/thawed LC cells from CB.

Cell Culture Techniques↗
PubMed2001

Expression of pyrimidine nucleoside phosphorylase (PyNPase) in colorectal cancer.

BACKGROUND: We investigated the expression of PyNPase both in cancer cells and in stroma cells to clarify the correlation between PyNPase expression and the prognosis of patients with colorectal cancer. METHODS: Using immunohistochemical staining with an anti-PyNPase antibody, the PyNPase expression in tissues from 114 patients with stage II or III colorectal cancer was examined. From the correlation between PyNPase expression and the clinicopathological findings, the prognosis for survival was analyzed. RESULTS: The expression of PyNPase was classified as negative or positive on the basis of staining. No relationship between PyNPase expression and any of the clinicopathological findings was identified. However, a relationship was observed regarding positive staining between cancer cells and stroma cells. The prognosis of patients with positive staining in both cancer cells and stroma was worse than that of other patients. In multivariate analyses, expression in cancer cells was the strongest predictor of prognosis. CONCLUSIONS: PyNPase expression appears to be a relevant factor for predicting the prognosis of colorectal cancer.

Adult↗
PubMed2001

Serine acetyltransferase involved in cysteine biosynthesis from spinach: molecular cloning, characterization and expression analysis of cDNA encoding a plastidic isoform.

A cDNA clone that encodes a chloroplast-localizing isoform of serine acetyltransferase (SATase) (EC 2.3.1.30) was isolated from spinach (Spinacia oleracea L.). The cDNA encodes a polypeptide of 347 amino acids containing a putative transit peptide of ca. 60-70 amino acids at the N-terminal. Deduced amino acid sequence of SATase from spinach exhibited homology with other SATases from plants. DNA blot hybridization analysis showed the presence of 2-3 copies of Sat gene in the genome of spinach. RNA blot hybridization analysis indicated the constitutive expression of Sat gene in green and etiolated seedlings of spinach. Bacterial expression of the cDNA could directly rescue the cysteine auxotrophy of Escherchia coli caused by a lack of SATase locus (cysE). Catalytically active SATase protein was produced in E. coli cells. L-Cysteine, an end product of the cysteine biosynthetic pathway, inhibited the activity of recombinant spinach SATase, indicating the regulatory function of SATase in this metabolic pathway. A chloroplastic localization of this spinach SATase was revealed by the analyses of transgenic plant expressing transit peptide of SATase-beta-glucuronidase (GUS) fusion protein, and transient expression using the transit peptide-green fluorescent protein (GFP) fusion protein. The result from in vitro translation analysis suggests that this cDNA may encode both plastidic and cytosolic SATases.

Acetyltransferases↗
PubMed2001

A new approach to enhancement of bone formation by electrically polarized hydroxyapatite.

An electrical field may affect osteogenesis. Since we found that hydroxyapatite (HA) ceramics may be polarizable, we hypothesized that electrically polarized HA may foster production of new bone in vivo. Both polarized and non-polarized HA ceramics were inserted into the subperiosteum spaces at the parietal bone area of rats. After 2, 4, and 8 weeks, the implant sites were examined histologically. Morphometric analysis revealed that new bone formation was accelerated on the negatively charged surface of the polarized HA (N-surface) at 2 weeks. The newly formed bone approached maturation at 4 weeks and was thicker on the N-surface than in the controls. By 8 weeks, newly formed bone in the controls was almost the same as that on the N-surface. These findings suggest that polarized HA is biocompatible and that bone formation on the N-surface is enhanced in the early stage of bone healing.

Animals↗
PubMed2001

Swimming speeds and buoyancy compensation of migrating adult chum salmon Oncorhynchus keta revealed by speed/depth/acceleration data logger.

Although the homing migration of Pacific salmon is well documented, the swimming behaviour of the returning salmon has been poorly described, principally as a result of the difficulties encountered in monitoring salmon behaviour in the sea. The present study describes the use of a recently developed electronic data logger to obtain simultaneous recordings of the swimming speed, depth, fin-beating activity and body angle of free-ranging chum salmon Oncorhynchus keta during their homing migration in coastal waters. Chum salmon migrated horizontally at speeds of 1.5-3.0 km h(-1). The gross horizontal distance salmon moved during total recording periods were 1.24- to 19.0-fold greater than the net distance from the release site to the retrieval points. It is suggested that homing salmon did not drift passively but swam actively to the spawning grounds. Salmon preferred the surface water, but also made frequent vertical migrations. The travelled depth of each salmon ranged from 0.36 to 0.64 km per hour. Salmon descended at faster rates and steeper angles than they ascended. Both tailbeat frequency and tail thrust were higher during the ascent than the descent phase. These results suggest that chum salmon spent more energy during the ascent than the descent phase. Profiles of descent rate assumed an arched shape with respect to a change in hydrostatic pressure, while ascent rate increased with decreasing depth. High tailbeat frequencies were found during the course of ascent, which suggests that the salmon did not regulate the volume of air in the swim bladder during short-term vertical migrations.

Animal Migration↗
PubMed2001

[Effects of glycosaminoglycans on the in vitro colony formation of CD34+ megakaryocytic progenitor cells in human placental/umbilical cord blood].

The in vitro effect of various glycosaminoglycans (GAGs) on the clonal growth of CD34+ megakaryocytic progenitor cells (CFU-Megs) isolated from human placental/umbilical cord blood (CB) was evaluated in human plasma containing semisolid culture stimulated by recombinant human thrombopoietin (TPO). The GAGs, including hyaluronic acid from human umbilical cords (HA-h), pig skins (HA-p) and rooster combs (HA-r), or keratan sulfate (KS), various chondroitin sulfates (CS-A, B, C, D, E), and heparan sulfate (HS), were tested. Each GAG alone did not affect the clonal growth of CFU-Meg. In the presence of TPO, adding of HA-p or HS (100 micrograms/ml) resulted in an approximately 1.3-fold increase, in the total number of colonies, due to an increase in large megakaryocyte colonies. In contrast, CS-E led to a marked decrease in CFU-Meg growth. At the end of the culture, the total number of cells increased 3.0-fold of the initial value of the control, but adding HA-p or HS showed an approximately 9.1-fold or 18.3-fold increase. Similarly, the total number of CFU-Meg detected in the harvested cells increased to 4.8-fold of the initial value, while, an approximately 18.3-fold or 38.8-fold increase was observed in the culture containing HA-p or HS, respectively. Flow cytometric analysis of the harvested cells showed no significant difference in the expression of surface antigens and DNA ploidy distribution of megakaryocytes between the control and GAG treatments. These results suggest that HA-p and HS promote the proliferation of immature CB CD34+ CFU-Meg in the presence of TPO.

Antigens, CD34↗
PubMed2001

Fulminant myocarditis in polymyositis.

Cardiac involvement in patients with polymyositis is usually asymptomatic and associated with a mild clinical course. A female patient with muscle weakness and cardiogenic shock, who was diagnosed with polymyositis and fulminant myocarditis, is described. A large amount of methylprednisolone, in addition to intra-aortic balloon pumping and percutaneous cardiopulmonary support, led to the recovery of her cardiac function. However, a massive cerebral embolism occurred and she died. Postmortem histopathological examination showed necroses of muscles and diffuse invasion of mononuclear cells in both the myocardium and the biceps muscle of her arm. Although the mechanism of cardiac dysfunction is not clear, immunosuppressive therapy was effective for fulminant myocarditis in the present case.

Acute Disease↗
PubMed2001

Usefulness of pulmonary vascular leakiness assessment in interstitial pneumonitis.

STUDY OBJECTIVE: Pulmonary vascular leakiness of (67)Ga-circulating transferrin in interstitial pneumonitis (IP) was estimated by our previously described method, and its ability to evaluate disease activity was compared with conventional (67)Ga scintigraphy. DESIGN: Using 30-min dynamic scanning data after IV injection of (67)Ga citrate, the exponential equilibration coefficient of (67)Ga between the intravascular and pulmonary interstitial compartments was calculated and defined as the leak index (LI). Pulmonary (67)Ga uptake was assessed by gallium index, determined by conventional static images taken 48 h after (67)Ga citrate injection. SETTING: Hospitalized patients. PARTICIPANTS: The study population consisted of 17 control patients and 20 patients with IP. RESULTS: The mean LI in patients with IP was significantly higher than in the control group (p < 0.0001), whereas no significant increase in gallium index was noted between the IP group and the control group. No significant correlation was found between gallium index and LI among all study participants. Mean LI in patients with active IP was significantly higher than in patients with stable IP (p = 0.0024). CONCLUSIONS: An increase in pulmonary vascular leakiness was found in patients with IP. LI may be useful to assess the disease activity.

Adult↗
PubMed2001

Vascular smooth muscle cell proliferation is effectively suppressed by the non-specific growth factor inhibitor suramin.

The purpose of this study was to investigate the effects of the non-specific growth factor inhibitor suramin on smooth muscle cell proliferation in vitro and in vivo. Cultured vascular smooth muscle cells (VSMC) were stimulated by platelet-derived growth factor (PDGF) and cellular DNA synthesis assessed by [3H]-thymidine uptake. Suramin dose-dependently inhibited DNA synthesis in VSMC, and 100 microM of suramin completely suppressed the PDGF-AB-induced cellular DNA synthesis. Rabbit carotid arteries were injured by the balloon catheter, and then suramin locally delivered using a porous balloon catheter over ten minutes. Three weeks after the vascular injury, the extent of intimal thickening was compared between the suramin-treated and control rabbits. The neointimal formation triggered by balloon-mediated vascular injury was suppressed significantly and dose-dependently by locally infused suramin, and the intima to media area ratios of the control and 1 mM suramin-treated animals were 48.8+/-14.9 and 12.2+/-6.0%, respectively (p < 0.01. n = 6 for each group). These results suggest that one time local administration of suramin was sufficient to suppress neointimal formation after balloon-mediated vascular injury, and that pharmacological intervention targeting the growth factor's signaling pathways could be a promising approach to prevent smooth muscle cell proliferation in various proliferative vascular diseases.

Animals↗
PubMed2001

[Hepatitis C virus genotyping by restriction fragment length polymorphism of polymerase chain reaction products generated with a HCV detection kit].

Highly conserved sequence in the 5' untranslated region(UTR) of hepatitis C virus(HCV) genome have been targeted by most nucleic acid amplification-based detection assays, such as Amplicor HCV test, a commercially available assay kit. In this study, we classified HCV genotypes by direct sequencing determination for 5' UTR of nested-PCR after Amplicor HCV test. Then, based on the results of sequence, RFLP analysis after digestion of the nested PCR fragments with Hae III or Sau 3AI to classify HCV genotype was evaluated. RFLP analysis distinguished the type 1, 2a and 2b. Only one of 29 samples was not classified by RFLP analysis due to the point mutation of Hae III recognition site. HCV genotypes commonly found in JAPAN were classified into three types, 1b, 2a, and 2b. Also, RFLP analysis requires fewer resources than serotype grouping test. Hence, the present method provides an adaptable and rapid HCV genotyping in clinical laboratory in JAPAN.

Base Sequence↗
PubMed2001

[Experience of gamma-detecting probe for the survey of sentinel node in gastroesophageal malignancies].

Gamma-detecting probe NAVIGATOR GPS (Autosuture Japan) was evaluated by using of 99mTc. Linearlity of counting in radioactivity was fairly good, but the sensitivity of the prove is so low, that sentinel node (SN) should contain the 3.7 x 10(-3) MBq (0.1 microCi) of 99mTc or more for the most effective use of it. And the count rate of the gamma-detecting probe was influenced by the distance and angle from the 99mTc source variously. It is important for the operator to know such characteristics of the gamma-detecting probe in order to obtain the correct SN judging.

Esophageal Neoplasms↗
PubMed2001

Sphingosylphosphorylcholine is an activator of transglutaminase activity in human keratinocytes.

We characterize functional roles of a newly discovered chemical, sphingosylphosphorylcholine (SPC), in the epidermis by elucidating the biological effect of SPC on human keratinocytes in culture. The intracellular calcium level of human keratinocytes was increased by incubation with SPC, but not with sphingosine (SS) or sphingomyelin (SM). The addition of SPC, sphingosine 1-phosphate (SSP), or SS to human keratinocytes at 10 microM concentrations also significantly suppressed DNA synthesis, and SPC, but not SSP, or SS increased the activities of membrane-bound and soluble transglutaminases (TGases). Reverse transcription polymerase chain reaction (RT-PCR) of TGase transcripts revealed that SPC treatment at 10 microM concentrations increased the expression of TGase 1 mRNA. The increased activity of soluble TGase was accompanied by the concomitant activation of cathepsin D as revealed by the increased ratio of mature active form to inactive intermediate form of the protease. Pretreatment of human keratinocytes with pepstatin, a protease inhibitor, blocked the increase in soluble TGase activity induced by treatment with SPC. Consistently, SPC treatment at 1-10 microM concentrations stimulated the cornified envelope formation. These findings suggest that SPC plays an important role in the altered keratinization process of epidermis in skin diseases with high expression of sphingomyelin deacylase, such as atopic dermatitis.

Calcium↗