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Biomedical subjects

K Toyama

Publications and source records attributed to K Toyama.

At least 73 records · Page 4Linked to original sources
PubMed1998

Human cord blood-derived primitive progenitors are enriched in CD34+c-kit- cells: correlation between long-term culture-initiating cells and telomerase expression.

We studied the functional characteristics of subpopulations of cord blood-derived CD34+ cells expressing different levels of CD38 and c-kit antigens, using clonal cell culture and long-term culture with allogeneic bone marrow stromal cells or the MS-5 murine stromal cell line to assay long-term culture-initiating cells (LTC-IC) in each subpopulation. To investigate the capacity for replication, proliferation, and differentiation of each subpopulation of CD34+ cells, we also studied the correlation between LTC-IC and telomerase activity. After 5 weeks of coculture, LTC-IC accounted for one out of 32 CD34+CD38- cells and one out of 33 CD34+c-kit- cells. In contrast, the frequency of LTC-IC was low in their antigen-positive counterparts (one per 84 CD34+CD38+ cells, one per 90 CD34+c-kit(low) cells, and very low among CD34+c-kit(high) cells). It was noteworthy that some LTC-IC derived from CD34+CD38- as well as CD34+c-kit- cells generated colony-forming cells (CFCs) after up to 9 weeks of coculture. Telomerase activity was consistently low in CD34+CD38- and CD34+c-kit- cells compared to CD38+ or c-kit(high or low) cells, suggesting that CD34+CD38- or c-kit- cells are likely to be more quiescent. These results suggest that the CD34+CD38- and CD34+c-kit- cell populations are primitive stem/progenitor cells, and that the telomerase activity of these cells correlates with their proliferative capacity as well as their stage of differentiation.

Animals↗
PubMed1998

Vitamin K2 selectively induces apoptosis of blastic cells in myelodysplastic syndrome: flow cytometric detection of apoptotic cells using APO2.7 monoclonal antibody.

We have previously reported that vitamin K2 (VK2) but not VK1 has a potent apoptosis-inducing effect on freshly isolated leukemia cells from patients with various types of leukemia. By multi-color flow cytometric analysis using monoclonal antibody (mAb), APO2.7, which detects mitochondrial 7A6 antigen specifically expressed by cells undergoing apoptosis, we further investigated the apoptosis-inducing effect of VK2 on minor populations of leukemic blast cells in bone marrow from patients with myelodysplastic syndrome (MDS) and overt myeloid leukemia (post-MDS AML). Limiting dilution of CD95 (anti-Fas) mAb-treated apoptotic Jurkat cells with nonapoptotic CTB-1 cells revealed that APO2.7-positive Jurkat cells were consistently detectable by flow cytometry when present at levels of at least 5% in the CTB-1 suspension. In patient samples the gating area for leukemic clone was determined using cell surface antigen-specific mAbs conjugated with either fluorescein isothionate (FITC) or phycoerythrin (PE) and subsequently the cells stained with phycoerythrin cyanine (PE-Cy5)-conjugated APO2.7 mAb were assessed within the gating area of the leukemic clone for monitoring apoptosis. Treatment of the bone marrow mononuclear cells with 3-10 microM of VK2 (menaquinone-3, -4 and -5) in vitro potently induced apoptosis of the leukemic blast cells as compared with the untreated control cells in all 15 MDS patients tested. This effect was more prominent on blastic cells than that on mature myeloid cells such as CD34-/CD33+ gated cells. In addition, VK2 performed much less effectively on CD3-positive lymphoid cells. In contrast to VK2, VK1 did not show apoptosis-inducing activity. These data suggest that VK2 may be used for treatment of patients with MDS in blastic transformation.

Antibodies, Monoclonal↗
PubMed1998

Sarcoidosis induced by interferon therapy for chronic myelogenous leukaemia.

A 31-year-old male was diagnosed as having chronic myelogenous leukaemia and has been treated with hydroxyurea and interferon-alpha since February 1995. After 16 months, he complained of low-grade fever and a cough. Bilateral hilar lymph node enlargement was detected on the chest X-ray film and multiple subcutaneous erythematous nodules appeared. A skin biopsy revealed subcutaneous sarcoid granuloma. Two months after the cessation of interferon therapy, the subcutaneous nodules and the hilar lymph node enlargement resolved. It is possible that continuous interferon administration can promote granuloma formation in sarcoidosis by activating T cells and macrophages.

Adult↗
PubMed1998

Simultaneous continuous 13C, 12C analysis of expired gas in the 13C breath test.

The 13C breath test is a method of clarifying the metabolism of loaded substances by administering 13C-labelled materials and calculating the 13CO2 and 12CO2 ratio (13C/12C isotope ratio) in the expired gas. The materials are metabolized and expelled in the expired gas. Because simultaneous continuous measurement of 13CO2 and 12CO2 in expired gas has been difficult up to the present, respective expired gases, including dead space before and after administration, have been sampled to separate sampling bags and 13C/12C has been measured in the bags and changed fraction of 13C/12C after administration (delta) has been used to judge the metabolic process. This method is affected by the contamination of the dead space gas. In the present study, in order to exclude the dead space effect, simultaneous continuous analysis of 12CO2 and 13CO2 of expired gas identifying alveolar gas was applied to the 13C-urea breath test in addition to the conventional sampling bag method. Both isotope detectors were attached to a mass spectrometer. Fifty-six cases receiving stomach health check-ups for Helicobacter pylori were examined. Delta was calculated in the bag or in phase III of continuous gas measurement. Because the bag contains dead space, delta was reduced and sensitivity and specificity with reference to gastric fluoroscopy or Helicobacter pylori IgG antibody were reduced. Decreasing the dead space contamination is important in reducing the measurement error in the 13C breath test and simultaneous continuous measurement is a good tool for this purpose.

Adult↗
PubMed1998

Detection of lung lesions and lymph nodes with 201Tl SPET.

The aim of this study was to characterize lung lesions by means of the uptake, retention and washout of 201Tl, and to quantify the sensitivity of 201Tl SPET (single photon emission tomography) in detecting mediastinal and hilar lymph nodes. A total of 68 patients with lung lesions (tumours and inflammation) underwent both helical computed tomography (CT) and 201Tl SPET examinations. Uptake, retention and washout parameters were calculated from early and delayed 201Tl SPET by drawing regions of interest over the primary lesion and the background of the lung. The findings on 201Tl SPET were compared with those on CT and surgical findings. A significant difference in the retention index (RI) was observed between primary malignant and benign lesions. In detecting lymph nodes, the sensitivity, specificity and negative predictive value were 83%, 60% and 90% respectively for early 201Tl SPET, and 50%, 80% and 80% respectively for delayed 201Tl SPET. 201Tl SPET with semi-quantitative analysis, especially RI, helps to differentiate between malignant and benign lung lesions. Lymph nodes larger than 1 cm on CT but not showing 201Tl uptake could be considered non-metastatic lesions.

Adult↗
PubMed1998

Detection of lung and chest tumours using 99Tcm-tetrofosmin: comparison with 201Tl.

The aim of this study was to assess the usefulness of 99Tcm-tetrofosmin for detecting tumours of the lungs and adjacent structures and to compare the results with those for 201Tl. In the 18 patients studied, there were 30 lesions in total. Dual-isotope SPET acquisitions were performed 10 min and 3 h after the administration of 99Tcm-tetrofosmin and 201Tl. Image quality and semi-quantitative parameters were evaluated for both tracers. All lesions were detected by the two radiopharmaceuticals on both the early and delayed images. In seven patients, the image quality of 99Tcm-tetrofosmin was better than that of 201Tl. For the detection of metastatic lymph nodes, the delayed 201Tl and the early 99Tcm-tetrofosmin images were superior. No significant difference was observed between the uptake ratios of the two tracers. 99Tcm-tetrofosmin showed significantly (P < 0.001) higher washout than 201Tl from both the lesions and normal lungs, although washout of 201Tl from normal lungs was significantly higher than that from the lesions. In conclusion, 99Tcm-tetrofosmin may be helpful for detecting tumours of the lungs and adjacent structures, but has limited applicability in differentiating between malignant and benign tumours and may not be used instead of 201Tl to detect malignant tumours of the lungs.

Adenocarcinoma↗
PubMed1998

[Clinical efficacy of fosfomycin in combination with sulbactam/cefoperazone in the treatment of severe infections complicated to blood dyscrasia. Working Group of Kanto Combination Therapy for FOM + SBT/CPZ].

In the treatment of severe infections complicated to blood dyscrasia, the efficacy and usefulness of fosfomycin (FOM) in combination with sulbactam (SBT)/cefoperazone (CPZ) were compared between patients receiving FOM in the first followed by SBT/CPZ (Group A) and those receiving both drugs simultaneously (Group B). The following results were obtained. 1. The efficacy rate was 56.3% for Group A and 47.9% for Group B, with no significant difference. 2. The efficacy for patients suspected of the presence of septicemia, the efficacy rate was 57.9% for Group A and 54.3% for Group B, with no significant difference. 3. As for underlying disease, patients with acute myelogenous leukemia were most prevailing. In these patients, the efficacy rate was 57.1% for Group A and 27.3% for Group B, with no statistically significant difference. However, the efficacy rate tended to be higher in Group A. 4. The administration of antibiotics was effective to restore the neutrophil count to 501/microliters or higher in 77.8% and 45.5% of the cases for Groups A and B, respectively, with significantly higher efficacy for Group A. 5. In the safety evaluation a total of 115 cases were included. Side effects and laboratory abnormalities were seen in 3 cases each, but none of them were serious in degree. From these results, it was confirmed that the combination therapy consisting of administration of FOM followed by SBT/CPZ with some interval is effective for severe infections complicated to blood dyscrasia.

Anti-Bacterial Agents↗
PubMed1998

A study of peripheral airway findings using an ultrathin bronchofiberscope and bronchoalveolar lavage fluid with diffuse panbronchiolitis.

We investigated the peripheral airways using an ultrathin bronchofiberscope and analyzed bronchoalveolar lavage fluid (BALF) in 10 patients with diffuse panbronchiolitis (DPB; refractory and responsive to treatment with macrolide antibiotics) and 10 healthy volunteers. Refractory DPB patients had obstruction at the 11th or 12th level of bronchial branches and secretion from the 5th to 6th order bronchi to the 11th-12th level of bronchial branches. In responsive DPB patients, there was no obstruction of peripheral airways, but secretion in the bronchial lumens still remained in nearly all observed bronchial branches. Despite macrolide therapy, BALF from patients with refractory DPB contained a high percentage of neutrophils and had a lower CD4/CD8 ratio. Two-color analysis of T cell subsets in BALF revealed a high percentage and number of CD8+S6F1+ cells (activated cytotoxic T cells) in refractory DPB patients. Our findings suggest that obstruction around the terminal bronchioles may be correlated with BALF abnormalities and may be irreversible despite macrolide therapy in progressive DPB.

Adult↗
PubMed1998

Alpha-fetoprotein producing pulmonary blastoma in a patient with systemic sclerosis: pathogenetic analysis.

We describe a rare case of pulmonary blastoma complicated with systemic sclerosis. The serum alpha-fetoprotein level was elevated at presentation and the biopsied tumour stained positively against anti-alpha-fetoprotein antibody. The alpha-fetoprotein produced autonomously by tumour cells was of yolk-sac origin. Although the pathogenesis of pulmonary blastoma has not been clarified, we suggest that this pulmonary blastoma is a type of yolk-sac tumour.

Female↗
PubMed1998

Stimulatory effects of substance P on CD34 positive cell proliferation and differentiation in vitro are mediated by the modulation of stromal cell function.

Substance P (SP) is a neuropeptide widely distributed in the nervous system. Extensive study has shown SP stimulates production of various cytokines by bone marrow stromal cells, although, the role of SP in hematopoietic phenomena is still unclear. Recently, we established a human cloned stromal cell line, HAS303, which can support hematopoietic stem cell proliferation and differentiation in vitro. We used this culture system to examine the effects of SP. Expression of the mRNAs of neurokinin (NK)-1R, NK-2R and NK-3R, specific SP receptors, on HAS303 cells was demonstrated by the RT-PCR. CD34+ cells isolated from bone marrow were co-cultivated with HAS303 cells in the presence and absence of SP and the total hematopoietic cells and progenitors were counted every 5 days. Introducing SP (10(-8) M) to the co-cultures significantly increased the number of total cells and progenitors compared with control cultures. SP showed no enhancing activity on CD34+ cells cultured alone. SP also stimulated IL-3-dependent colony formation of whole bone marrow MNCs in a soft agar culture system, but showed no such activity on isolated CD34+ cells in this system. These observations suggest that SP stimulated HAS303 cells, activated HAS303 cells, and stimulated the proliferation and differentiation of CD34+ cells. Treating HAS303 cells with SP increased the intracellular Ca2+ concentration and stimulated production of G-CSF, GM-CSF, SCF and IL-6, but not IL-1alpha, IL-1beta and TNF-alpha, but did not enhance proliferation. All these findings suggest that SP mediates hematopoietic cell proliferation and differentiation in vitro by activating stromal cell function.

Antigens, CD34↗
PubMed1998

Comparison of telomerase activity in normal chorionic villi to trophoblastic diseases.

Trophoblasts are derived from the normal placenta, and they infiltrate into the endometrium and the maternal blood vessels under strict control but, unlike malignant cells, never metastasize. To understand the proliferative characteristics of trophoblasts and its related disorders, we assessed telomerase activity in chorionic villi obtained from 27 normal individuals, 9 hydatidiform moles, and 2 choriocarcinomas. Telomerase activity was detected in 13/27 (48%) normal chorionic villi samples. The detectability and the level of telomerase activity depended on gestational age; 8/10 (80%) villi samples in the first trimester (relative telomerase activity; 1.77 +/- 1.37), whereas 2/8 (25%) villi samples in the second trimester (0.78 +/- 1.52) and 3/9 (33%) in the third trimester (0.28 +/- 0.43) had telomerase activity. Telomerase activity of normal chorionic villi in the first trimester was higher than that of the third trimester (P = 0.0251). In contrast, all mole samples had increased telomerase activity compared to normal villi (3.17 +/- 2.81, P = 0.0152). Thus, a relationship may exist among cell proliferation, telomerase activity, and progression to trophoblastic disease.

Adult↗
PubMed1998

Serum soluble CD44 levels for monitoring disease states in acute leukemia and myelodysplastic syndromes.

To determine the clinical implications of soluble CD44 (sCD44) levels in hematologic neoplasias, we developed an enzyme-linked immunosorbent assay for sCD44 using two monoclonal antibodies to the standard 90 kDa form, and assessed the serum concentration of sCD44 in normal healthy volunteers, patients with acute leukemia, myelodysplastic syndromes (MDS), and those with chronic myeloid leukemia (CML). Compared to that in normal individuals (n=51; 145. 1 24.6 ng/ml), the serum sCD44 level was significantly elevated in patients with acute myeloid leukemia (AML; n=18; 331.9 99.0 ng/ml, P=0.0001), acute lymphoid leukemia (ALL; n=16; 551.3 427.8 ng/ml, P=0.0001) and CML (n=18; 262.0 97.5 ng/ml, P=0.0001). The sCD44 level was slightly elevated in patients with MDS (n=43; 173.8 54.9 ng/ml, P=0.0071). In patients with acute leukemia, serum sCD44 concentrations decreased significantly in response to treatment and reached nearly normal levels after complete remission (P=0.0005 in AML and P=0.0032 in ALL). The sCD44 levels in patients with MDS increased after they developed acute leukemia, whereas no significant difference in sCD44 levels was observed between the chronic and the blastic phases in patients with CML. Our results indicate that serum sCD44 levels may be a useful marker for monitoring response to treatment and disease progression, especially in acute leukemia.

Acute Disease↗
PubMed1998

[Induction of Ph-negative normal clone and long-term survival by combined treatment with G-CSF plus middle dose cytosine arabinoside for patients with chronic myeloid leukemia in blastic transformation].

Three patients with chronic myeloid leukemia (CML) in blastic transformation were treated with G-CSF plus middle dose cytosine arabinoside (Ara-C). G-CSF was administered (150 mg, s.c. or 300 mg, d.i.v./day) 24 hr prior to Ara-C (2-3 g/body, 6 hour d.i.v. for 2-5 days) and continued until the peripheral neutrophil count rose above 1,000/microlitre. As a supplement, VP-16 (80 mg/m2, for 2 days) was administered as warranted to control the growth of blastic cells. All 3 patients survived for more than 12 months with a favorable performance status. Normal karyotypes were detected in 2 of the patients after chemotherapy. One of those patients in paticular demonstrated normal bone marrow findings with the almost complete disappearance of the Ph-positive clone. In vitro cultures of peroxidase-negative CML blastic cells revealed that G-CSF stimulated the induction of blastic cells into the cell cycle and that blastic cell apoptosis was more pronounced in cells cultured with G-CSF plus Ara-C than with G-CSF or Ara-C alone. G-CSF plus middle dose Ara-C therapy appears to be a strong candidate for the treatment of CML in blastic transformation with a poor prognosis.

Adult↗
PubMed1998

Enhanced engraftment of intravenously transplanted hematopoietic stem cells into bone marrow of irradiated mice treated with AcSDKP.

The effect of the tetrapeptide Acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) on intravenously transplanted hematopoietic stem cell engraftment into the bone marrow (BM) of irradiated mice was studied. When 5 x 10(4) marrow cells were transplanted into lethally irradiated mice given 10 microg AcSDKP, the survival of these animals 4 weeks posttransplantation increased markedly from 20.0 +/- 4.4% to 86.1 +/- 4.8%, the same result as that obtained from mice transplanted with 5 x 10(5) cells without AcSDKP treatment. Increased numbers of hematopoietic stem cells, including spleen colony-forming unit and colony-forming unit granulocyte-macrophage, were observed in the BM of AcSDKP-treated mice 1 and 8 days after transplantation. This finding suggested that AcSDKP influenced homing of hematopoietic stem cells into the BM of lethally irradiated animals. This enhancing activity of AcSDKP was neutralized by the simultaneous administration of an anti-AcSDKP polyclonal antibody. Furthermore, recovery of leukocytes in peripheral blood occurred faster in AcSDKP-treated than in untreated transplanted mice. These findings may provide a basis for the clinical use of AcSDKP in BM transplantation patients.

Animals↗
PubMed1998

Technetium-99m-tetrofosmin, technetium-99m-MIBI and thallium-201 uptake in rat myocardial cells.

UNLABELLED: The mechanisms of uptake and intracellular distribution of 99mTc-tetrofosmin, 99mTc-MIBI and 201TI and the behaviors of 99mTc-tetrofosmin and 99mTc-MIBI in relation to Na+ were studied with primary cultures of myocardial cells. METHODS: Both the uptake and the washout of the tracers were sequentially measured. The cells were treated with ouabain, bumetanide, tetrodotoxin, dimethyl amiloride (DMA), nigericin and carbonyl cyanide m-chlorophenylhydrazone (CCCP) to observe the effects of the uptake and intracellular distribution of the traders. Cells equilibrated in buffers with or without Na+ were treated with monensin and DMA to evaluate the effect of Na+ on the accumulation of the tracers. RESULTS: Despite the similarities in uptake kinetics, there was a higher level of retention of 99mTc-tetrofosmin inside the cells. Ouabain, bumetanide and tetrodotoxin did not show any inhibitory effect on the uptake of 99mTc-tetrofosmin and 99mTc-MIBI, whereas they produced various degrees of inhibition of 201TI uptake. DMA produced approximately 35% inhibition of 99mTc-tetrofosmin uptake and 50% inhibition of 99mTc-MIBI uptake. Nigericin increased the uptake of 99mTc-MIBI by the cells. The addition of CCCP produced the release of 38% of the accumulated 99mTc-tetrofosmin and 52%-70% of the accumulated 99mTc-MIBI, indicating that these percentages of accumulation were related to mitochondrial uptake. Neither Na+-free buffer nor monensin had any significant effect on 99mTc-tetrofosmin accumulation, but they both caused increased accumulation of 99mTc-MIBI. CONCLUSION: The uptake of both 99mTc-tetrofosmin and 99mTc-MIBI through the cell membrane is partly related to the Na+/H+ antiporter system. Only part of the accumulated 99mTc-tetrofosmin inside the cells enters into mitochondria; most of the accumulated 99mc-MIBI is related to mitochondrial uptake. This uptake may be related to Na+.

Amiloride↗
PubMed1998

[The advantage of an in situ TRAP assay for the detection of telomerase activity using bronchial washings obtained from lung cancer patients].

In most previous reports telomerase activity in lung cancer patients has been detected using tissue extracts. We have developed a semiquantitative fluorescence-based TRAP assay using fluorescence-end-labeling primers. Moreover, we also developed an in situ TRAP assay that detects telomerase activity at the cellular level. Thus, using these TRAP assays, we can detect telomerase activity in lung cancer cells obtained from bronchial washings. A high incidence of lung cancer patients with class I-III cytology had detectable telomerase activity, thus, a combination of a cell extract based. TRAP assay and an in situ TRAP assay may provide additive information to cytology for the diagnosis of lung cancer.

Bronchoalveolar Lavage↗