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T Higuchi

Publications and source records attributed to T Higuchi.

At least 163 records · Page 9Linked to original sources
PubMed1999

Apoptosis of erythroid precursors under stimulation with thrombopoietin: contribution to megakaryocytic lineage choice.

Although the effect of thrombopoietin (TPO) on megakaryocyte production is well established, its role in the commitment of multipotential hematopoietic progenitors to the megakaryocytic lineage remains to be determined. In the present study, we attempted to clarify the determination process of megakaryocytic lineage as a terminal differentiation pathway under stimulation with TPO. Day 7 cultured cells grown by TPO derived from cord blood CD34+ cells were divided into four subpopulations on the basis of CD34 and CD41 expression. The CD34-/CD41- cells showed the labeling pattern of anti-CD42b and anti-CD9 antibodies closer to that of the CD34+/CD41- cells than the CD34+/CD41+ cells. Replating experiments revealed that approximately 40% of the CD34-/CD41- cells proliferated in response to a combination of growth factors, and more than 80% of them were pure erythroid precursors. However, this subpopulation failed to grow/survive and fell into apoptosis in the presence of TPO alone. In contrast, the CD34+/CD41+ cells, which predominantly contained megakaryocytic precursors, exerted a low but significant proliferative potential in the presence of TPO. The insufficient response to TPO of the CD34-/CD41- cells may result from the apparently low expression of c-MpI, as determined by flow cytometric analysis and reverse transcription-polymerase chain reaction analysis. Therefore, these results suggest that the apoptosis of hematopoietic precursors other than megakaryocytic precursors is related to the determination of the terminal differentiation under the influence of TPO.

Antigens, CD↗
PubMed1999

Chemokine production by human megakaryocytes derived from CD34-positive cord blood cells.

To clarify the roles of megakaryocytes and platelets in the responses associated with infection and inflammation, we examined the effects of interleukin (IL) 1, the common mediator of the inflammatory process, on the development and secretory functions of megakaryocytes generated from CD34(+)cord blood cells under stimulation with thrombopoietin (TPO). The addition of IL-1alpha did not influence the generation, endomitosis or expression of surface makers of megakaryocytes, compared with TPO alone. However, IL-1alphaenhanced the ability of megakaryocytes to produce IL-8 and growth-regulating oncogene-alpha(GRO-alpha) in the presence of TPO. In contrast, the production of regulated on activation with normal T cell expressed and secreted (RANTES), platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG) were not potentiated. A flow cytometric analysis and a reverse transcription-polymerase chain reaction analysis revealed IL-1 receptor type I (IL-1RI) expression of megakaryocytes generated by TPO. Moreover, the addition of an anti-IL-1RI monoclonal antibody significantly decreased the TPO plus IL-1alpha-induced secretion of IL-8 by the cultured megakaryocytes to the level attained by TPO alone. These results suggest that the production of IL-8 and GRO-alpha (but not RANTES), PF4 and beta-TG, by megakaryocytes is potentiated by signalling through IL-1RI with the aid of TPO. Thus, megakaryocytes and platelets may play an important role in the development of inflammation via chemokine release.

Antigens, CD34↗
PubMed1999

Evaluation of In-111 DTPA-paclitaxel scintigraphy to predict response on murine tumors to paclitaxel.

UNLABELLED: Our goal was to determine whether scintigraphy with 111In-DTPA-paclitaxel could predict the response to chemotherapy with paclitaxel. METHODS: Ovarian carcinoma (OCA 1), mammary carcinoma (MCA-4), fibrosarcoma (FSA) and squamous cell carcinoma (SCC VII) were inoculated into the thighs of female C3Hf/Kam mice. Mice bearing 8 mm tumors were treated with paclitaxel (40 mg/kg). The growth delay, which was defined as the time in days for tumors in the treated groups to grow from 8 to 12 mm in diameter minus the time in days for tumors in the untreated control group to reach the same size, was measured to determine the effect of paclitaxel on the tumors. Sequential scintigraphy in mice bearing 10 to 14 mm tumors was conducted at 5, 30, 60, 120, 240 min and 24 hrs postinjection of 111In-DTPA-paclitaxel (3.7MBq) or 111In-DTPA as a control tracer. The tumor uptakes (% injection dose/pixel) were determined. RESULTS: The growth delay of OCA 1, MCA-4, FSA and SCC VII tumors was 13.6, 4.0, -0.02 and -0.28 days, respectively. In other words, OCa 1 and MCA-4 were paclitaxel-sensitive tumors, whereas FSA and SCC VII were paclitaxel-resistant tumors. The tumor uptakes at 24 hrs postinjection of In-111 DTPA paclitaxel of OCA 1, MCA-4, FSA and SCC VII were 1.0 x 10(-3), 1.6 x 10(-3), 2.2 x 10(-3) and 9.0 x 10(-3) % injection dose/pixel, respectively. There was no correlation between the response to chemotherapy with paclitaxel and the tumor uptakes of 111In-DTPA-paclitaxel. CONCLUSIONS: Scintigraphy with 111In-DTPA-paclitaxel could not predict the response to paclitaxel chemotherapy. Although there was significant accumulation of the paclitaxel in the tumor cells, additional mechanisms must be operative for the agent to be effective against the neoplasm. 111In-DTPA-paclitaxel activity is apparently different from that of paclitaxel with Cremophor.

Animals↗
PubMed1999

Excitation of oxytocin cells in the hypothalamic supraoptic nucleus by electrical stimulation of the dorsal penile nerve and tactile stimulation of the penis in the rat.

In urethane-anaesthetized male rats, electrical stimulation of the dorsal penile nerve (DPN) excited 29 of 48 (60%) oxytocin cells in the contralateral supraoptic nucleus, whereas only 5 of 28 (18%) vasopressin cells were excited by the stimulation. The stimulus applied to the ipsilateral DPN to the recorded neurone also excited a similar proportion of oxytocin cells (25 of 43; 58%). Tactile stimulation of the glans penis excited 7 of 12 (58%) oxytocin cells, whereas the same stimulation excited only 3 of 16 (19%) vasopressin cells. The results suggest that sensory information arising from the penis preferentially excites oxytocin cells in the supraoptic nucleus.

Animals↗
PubMed1999

Noninvasive assessment of tumor hypoxia with 99mTc labeled metronidazole.

PURPOSE: The assessment of tumor hypoxia by imaging modality prior to radiation therapy would provide a rational means of selecting patients for treatment with radiosensitizers or bioreductive drugs. This study aimed to develop a 99mTc-labeled metronidazole (MN) using ethylene-dicysteine (EC) as a chelator and evaluate its potential use to image tumor hypoxia. METHODS: EC was conjugated to amino analogue of MN using Sulfo-N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-HCl as coupling agents, the yield was 55%. Tissue distribution of 99mTc-EC-MN was determined in breast tumor-bearing rats at 0.5, 2, and 4 hrs. Planar imaging and whole-body autoradiograms were performed. The data was compared to that using 99mTc-EC (control), [18F]fluoromisonidazole (FMISO) and [(131)I] iodomisonidazole (IMISO). RESULTS: In vivo biodistribution of 9mTc-EC-MN in breast tumor-bearing rats showed increased tumor-to-blood and tumor-to-muscle ratios as a function of time. Conversely, tumor-to-blood values showed time-dependent decrease with 9mTc-EC in the same time period. Planar images and autoradiograms confirmed that the tumors could be visualized clearly with 99mTc-EC-MN from 0.5 to 4 hrs. There was no significant difference of tumor-to-blood count ratios between 99mTc-EC-MN and [(131)I]IMISO at 2 and 4 hrs postinjection. From 0.5 to 4 hrs, both 9mTc-EC-MN and [(131)I]MISO have higher tumor-to-muscle ratios compared to [18]FMISO. CONCLUSIONS: It is feasible to use 9mTc-EC-MN to image tumor hypoxia.

Animals↗
PubMed1999

Polymorphisms in the 5'-flanking region of tumor necrosis factor-alpha gene in patients with rheumatoid arthritis.

Polymorphisms in the 5'-flanking promoter/enhancer region of the tumor necrosis factor (TNF)-a gene were examined to study the genetic background of rheumatoid arthritis (RA). Four variant alleles, -1,031C/ -863A, -1,031C/-238A, -857T and -308A, were identified and examined in 387 RA patients and 575 healthy Japanese controls. The frequency of the -857T allele in RA patients was significantly higher than that in the controls. However, the HLA-DRB1 analysis in the same subjects showed that the DRB1*0405 allele, which is in linkage disequilibrium with the -857T, was more strongly associated with the disease susceptibility than the -857T allele. These results suggest that the susceptible gene to RA is more closely linked to the HLA-DRB1 locus than to the TNF-alpha locus.

5' Untranslated Regions↗
PubMed1999

Effect of prophylactic administration of hyperimmune plasma to prevent Rhodococcus equi infection on foals from endemically affected farms.

The effect on foals of prophylactic administration of hyperimmune plasma to prevent R. equi infection was investigated on three farms at which R. equi infection was endemic. Sixteen foals between 10 and 39 days of age were intravenously given 1-21 of hyperimmune plasma. ELISA antibody titres against R. equi were significantly increased and maintained at high levels for over 30 days in most of the recipient foals. The prevalence of R. equi infection was 6.3% (1/16) in the foals that received the immune plasma, and 26.3% (5/19) in the control foals not given the immune plasma on the three farms. For 2 years before and after this field trial on the three farms, 18 of 64 foals (28.1%) showed clinical signs of respiratory tract infection and four of them died of R. equi pneumonia. Heavy contamination of horses and their environment with virulent R. equi was detected by colony blotting, and plasmid profiles also suggested that foals on the three farms were constantly exposed to virulent R. equi. The results of this field trial support previous observations by some researchers that the administration of hyperimmune plasma to foals in the early days of life promotes prevention of R. equi infection on endemic farms; however, the mechanism of hyperimmune plasma protection remains unclear.

Actinomycetales Infections↗
PubMed1999

Double-blind test on the efficacy of methylcobalamin on sleep-wake rhythm disorders.

The therapeutic effect of methylcobalamin (Met-12) on sleep-wake rhythm disorders was examined in a double-blind test. In the test group which was given a large dosage, a higher percentage of improvement was found compared to the control group with a small dosage, although the difference was not significant. The test group inconsistently showed significant improvement in both the sleep-wake cycle parameters and in clinical symptoms. The tendency was for the results to show a beneficial effect of Met-12 on rhythm disorders. However, because the percentage of improvement was low and significant improvement was inconsistent, Met-12 might be considered to have a low therapeutic potency and possible use as a booster for other treatment methods of the disorders.

Affect↗
PubMed1999

Analysis of tumor necrosis factor-alpha production and polymorphisms of the tumor necrosis factor-alpha gene in individuals with a history of Kawasaki disease.

BACKGROUND: Tumor necrosis factor (TNF)-alpha plays a central role in the pathogenesis of vasculitis in Kawasaki disease (KD). To address the genetic background of KD, we investigated the level of TNF-alpha production and genetic polymorphisms in the 5' flanking region of the TNF-alpha gene in healthy children with a history of KD. METHODS: For TNF-alpha production, peripheral blood mononuclear cells (PBMC) of children with a history of KD (n = 61) and of non-KD children (n = 35) were stimulated with phorbol 12-myristate 13-acetate, toxic shock syndrome toxin-1 (TSST-1) and the culture supernatant of Staphylococcus aureus derived from a KD patient (S-6), which had several superantigenic activities. The genetic background of KD was addressed by studying polymorphisms in the 5' flanking region of the TNF-alpha gene at positions -1031 (thymine (T) to cytosine (C) change, termed -1031C), -863 (C to adenine (A), -863A), -857 (C to T, -857T), -308 (guanine (G) to A, -308A) and -238 (G to A, -238A) in KD, using dot-blot hybridization with sequence-specific oligonucleotide probes. RESULTS: The PBMC of KD patients with coronary artery lesions produced slightly higher levels of TNF-alpha in response to the bacterial products (such as TSST-1 and S-6). None of the polymorphisms in the 5' flanking region of the TNF-alpha gene were related to KD. CONCLUSIONS: These results suggest that a genetic disposition towards overproduction of TNF-alpha in response to bacterial products may be involved in the pathogenesis of KD.

Adolescent↗
PubMed1999

Co-expression of integrin-associated protein (IAP/CD47) and its ligand thrombospondin-1 on human granulosa and large luteal cells.

In the present study, we have raised a monoclonal antibody (mAb) designated OG-4 against human granulosa cells (GC). By immunohistochemistry, the expression of OG-4 antigen was observed on human GC and large luteal cells, but not on thecal and small luteal cells. A complementary DNA (cDNA) clone encoding OG-4 antigen was screened and isolated by a panning method using OG-4 mAb from a human corpus luteum (CL) cDNA library that was expressed transiently in COS-7 cells. Nucleotide sequencing revealed that OG-4 antigen was identical to integrin-associated protein (IAP)/CD47 antigen. Subsequent reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that the isoform 2 mRNA of IAP is predominantly expressed in human GC and CL. The expression of thrombospondin-1 (TSP-1), which is a ligand for IAP, was also observed in human GC by immunocytochemistry and RT-PCR. Co-expression of IAP and TSP-1 on human GC may suggest that TSP-1 has a physiological role in GC function possibly via IAP in an autocrine fashion.

Adult↗
PubMed1999

Expression of calcium binding protein D-9k messenger RNA in the mouse uterine endometrium during implantation.

To investigate the molecular mechanisms of implantation, we constructed a cDNA library of mouse uteri enriched with pregnancy-induced genes by subtractive hybridization and polymerase chain reaction (PCR). One of the isolated clones was the cDNA for the calcium binding protein D-9k (Cabp9k), which is considered to regulate intracytoplasmic concentration and transport of free calcium ions. Northern blot and in-situ hybridization analyses demonstrated that the Cabp9k mRNA was expressed in the endometrial epithelia, both luminal and glandular, in the uterus at the time of implantation. On pregnancy day 5 it was detected in the luminal, but not in the glandular, epithelia. In the oophorectomized adult mice, progesterone enhanced Cabp9k mRNA expression in the uterus, whereas oestrogen did not. Consistent with this, a nucleotide change was identified in the first intron of mouse Cabp9k gene corresponding to the oestrogen responsive element in the rat Cabp9k gene. Transfer of embryos into the uterine cavity of pseudopregnant mice reduced the expression of Cabp9k mRNA in the glandular epithelium, suggesting that Cabp9k mRNA expression is also regulated by embryonal signal(s). These findings demonstrated that Cabp9k mRNA is expressed in the endometrial epithelia during the implantation period under the control of progesterone and the presence of embryo, and suggest that CaBP9k plays a role in implantation by regulating the local calcium concentrations.

Amino Acid Sequence↗
PubMed1999

CD9 is expressed in extravillous trophoblasts in association with integrin alpha3 and integrin alpha5.

The CD9 molecule is a 24-27 kDa cell surface glycoprotein, which may be related to Schwann cell migration and adhesion. In this study, we examined the expression of CD9 in human extravillous trophoblasts, which invade into the endometrium during implantation and placentation. CD9 was detected immunohistochemically on the extravillous trophoblasts in the cell columns of first trimester placentae, but not on villous trophoblasts. In the second and third trimester, CD9 was highly expressed on the extravillous trophoblasts in the basal plate of placentae, and in the chorion laeve in the fetal membrane of term placentae. The molecular mass of CD9 in the chorion laeve was shown to be 27 kDa by Western blotting. The mRNA of CD9 was also detected in the chorion laeve by reverse transcription-polymerase chain reaction (RT-PCR). Proteins were purified from chorion laeve by affinity chromatography with anti-integrin alpha3 and alpha5 monoclonal antibodies and Western blotting, revealed that CD9 was associated with both integrins. These findings indicate that CD9 is a differentiation-related molecule present in the extravillous trophoblasts. Since it is associated with integrin alpha5 which has been proposed to regulate trophoblast invasion, CD9 may be implicated in trophoblast invasion at the feto-maternal interface.

Antigens, CD↗
PubMed1999

CD9 is involved in invasion of human trophoblast-like choriocarcinoma cell line, BeWo cells.

The CD9 molecule is expressed on human extravillous trophoblasts, which invade the endometrium during implantation and placentation. To elucidate the role of CD9 in trophoblastic function, we investigated the expression of CD9 protein and mRNA in BeWo cells, a human trophoblast-like choriocarcinoma cell line, using immunohistochemistry, Western blotting and reverse transcription-polymerase chain reaction (RT-PCR). When BeWo cells were cultured with anti-CD9 monoclonal antibodies (mAb), their invasion through the extracellular matrices was significantly enhanced in a dose-dependent manner. Cell proliferation and human chorionic gonadotrophin production were unaffected. On the other hand, culture in the presence of mAb against integrins alpha3, alpha5 and beta1, which partially block the interaction with the extracellular matrices, inhibited BeWo cell invasion. Anti-CD9 monoclonal antibody had a stimulatory effect on BeWo cell invasion in the presence of anti-integrin alpha3 antibody. In contrast, it had no effect in the presence of mAb against integrins alpha5 and beta1, which were also highly expressed on BeWo cells. These findings suggest that CD9 has a function connected with the invasive properties of BeWo cells, which is partially mediated by integrin alpha5beta1. This may relate to the involvement of CD9 in trophoblastic invasion.

Antibodies, Monoclonal↗
PubMed1999

Human granulosa cells express integrin alpha2 and collagen type IV: possible involvement of collagen type IV in granulosa cell luteinization.

Previously, it has been shown that integrin alpha6beta1 expressed on human granulosa cells regulates luteinization in co-operation with its ligand, laminin. In this study, integrin alpha2 was immunohistochemically demonstrated to be expressed on granulosa and large luteal cells. It was also detected on luteinizing theca interna cells after ovulation. Immunoreactive collagen type IV, which is one of the ligands for integrin alpha2beta1, was detected around granulosa cells in the pre-ovulatory follicles and its expression was rapidly increased during ovulation. By flow cytometry, collagen type IV was detected on the cell surface of luteinizing granulosa cells isolated from pre-ovulatory follicles, confirming the physiological interaction between granulosa cells and collagen type IV. Collagen type IV in follicular fluid was positively related with progesterone concentration. In 4-day cultures of granulosa cells, collagen type IV in the media was significantly increased by human chorionic gonadotrophin (HCG). The progesterone production was significantly attenuated when granulosa cells were cultured on collagen type IV-coated dishes, suggesting that collagen type IV suppresses granulosa cell luteinization. These findings show that collagen type IV, a ligand for integrin alpha2beta1, is rapidly produced around luteinizing granulosa cells during ovulation, probably under the control of luteinizing hormone (LH) and suggest that collagen type IV is a new parameter and/or regulator of granulosa cell luteinization in the periovulatory phases.

Antigens, CD↗
PubMed1999

Biodistribution and scintigraphy of [111In]DTPA-adriamycin in mammary tumor-bearing rats.

The aim of this study was to develop an 111In-labeled diethylenetriamine pentaacetic acid-adriamycin (DTPA-ADR) conjugate to image breast cancer. DTPA-ADR was synthesized by reacting adriamycin with DTPA anhydride in the presence of carbonyldiimidazole. After dialysis (MW cut off was 500), the product was freeze-dried (yield 40-50%). An in vitro cell culture study was performed using cells from the 13,762 Fischer rat mammary tumor line. Drug concentrations tested were 0.1-100 microM. Biodistribution studies were conducted at 0.5, 2, 24 and 48 h in mammary tumor-bearing rats (n = 3/time interval, 10 microCi/rat, i.v.) with 13,762 cells (10(5) cells/rat, s.c.). Planar imaging and autoradiograms were obtained at the same intervals. In vitro cell culture assays showed an IC50 of 0.1 +/- 0.01 microM for ADR and 7.2 +/- 0.29 microM for DTPA-ADR, respectively. In biodistribution studies, tumor/blood uptake ratios of [111In]DTPA-ADR at 0.5, 2, 24 and 48 h were 0.55 +/- 0.17, 0.94 +/- 0.17, 3.06 +/- 0.53 and 3.66 +/- 0.35, respectively, whereas those for [111In]DTPA (control) were 1.19 +/- 0.69, 0.84 +/- 0.07, 0.56 +/- 0.10 and 0.60 +/- 0.03, respectively. The tumor uptake value (%ID/g) of [111In]DTPA-ADR at 0.5 h was 0.20 +/- 0.06. Planar images and autoradiograms showed good visability of tumors. Biodistribution, autoradiography and radionuclide imaging of [111In]DTPA-ADR in breast tumor-bearing rats showed that tumor-to-blood ratios increased steadily between 30 min and 48 h. These results indicate that DTPA-ADR, a new cancer imaging agent, might be useful in the diagnosis of breast cancer and may predict a therapeutic effect prior to treatment.

Animals↗
PubMed1999

Metabolic studies of [18F-alpha-methyl]tyrosine in mice bearing colorectal carcinoma LS-180.

Brain and tumor uptake of [18F-alpha-methyl]tyrosine (18F-AMT) and the incorporation into each of four fractions (lipid, RNA, DNA and protein) were investigated in mice bearing LS180 colorectal carcinoma. Homogenized tissues were analyzed by the fractionation method into an acid-soluble fraction (ASF) and an acid-precipitable fraction (APF). The APF was further investigated to assess the incorporation of 18F-AMT into each fraction. Incorporation into four fractions of brain and tumor at 60 min post-injection was 20 and 12%, respectively; 10% of the activity was incorporated to lipid in brain and 5% in tumor. There was 5, 2 and 2% incorporation with RNA, DNA and protein, respectively. Metabolites in ASF were analyzed by high-performance liquid chromatography and thin-layer chromatography. There was only one radioactive peak, which corresponded to 18F-AMT. The incorporation of 18F-AMT into lipid was twice that of 18F-AMT in tumor. The uptake of 18F-AMT in tissues was rapid and accomplished before 30 min, and then slowly diffused in blood. These results implied that 18F-AMT was metabolized to protein to only a small extent and trapped as intact 18F-AMT in cells up to 60 min. We conclude that 18F-AMT is a promising tracer for tumor imaging and quantification of the transport rate using two-compartment models.

Animals↗
PubMed1999

Magnetic resonance imaging of pseudotumors of the craniovertebral junction in long-term hemodialysis patients.

BACKGROUND/AIMS: Pseudotumors of the craniovertebral junction (PTCVJ) are observed in long-term hemodialysis (HD) patients. There are neither criteria for diagnosis nor guidelines for screening. We attempted to determine magnetic resonance imaging (MRI) findings that could be used to detect PTCVJ, to determine the prevalence of PTCVJ, and to evaluate whether destructive spondyloarthropathy (DSA) might be a yardstick for selection of patients for MRI examination for PTCVJ. METHODS: MRI were examined in 19 DSA patients (8 males, 11 females, age 61.4 +/- 7.3 years, HD duration 17.0 +/- 4.4 years) and in 20 sex-, age-, and HD-duration-matched non-DSA patients (9 males, 11 females, age 57.5 +/- 6.6 years, HD duration 17.7 +/- 4.9 years). We evaluated MRI characteristics of PTCVJ according those which occur due to rheumatoid arthritis. RESULTS: PTCVJ were characterized as follows: disappearance of fat pads in the upper region (supradental PTCVJ), intensity change of the 'predental triangle' in the anterior region (predental PTCVJ), and thickening of cruciform ligaments (retrodental PTCVJ). The prevalence of PTCVJ among patients undergoing HD more than 10 years was high (26 out of 39; 66.7%). The prevalence of PTCVJ was not different between DSA and non-DSA groups. CONCLUSION: We verified that the above MRI findings might be helpful in the detection of PTCVJ. These findings were observed frequently and independently also in patients with DSA.

Amyloidosis↗