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Biomedical subjects

T Yamaguchi

Publications and source records attributed to T Yamaguchi.

At least 793 records · Page 44Linked to original sources
PubMed1997

Bioassay of human granulocyte colony-stimulating factor using human promyelocytic HL-60 cells.

A new method for an assay of human granulocyte colony-stimulating factor (hG-CSF) has been developed using human promyelocytic HL-60 cells. The proliferation of HL-60 cells had been suppressed by the addition of dimethyl sulfoxide (DMSO) or retinoic acid (RA). These differentiating agent-treated HL-60 cells exhibited an increase in their number in response to recombinant hG-CSF (rhG-CSF). Neither dibutyl-cAMP nor interferon-gamma (IFN-gamma)-treated HL-60 cells, however, showed an increase in their number in response to rhG-CSF. The proliferation rate of DMSO-pretreated HL-60 cells was linearly increased from 0.3 to 10 ng/ml of rhG-CSF. L-Value of HL-60 cells assay was 0.027 +/- 0.012. The activities of non-glycosylated rhG-CSF produced by Escherichia coli and glycosylated rhG-CSF produced by chinese hamster ovary (CHO) cells were compared using DMSO-treated HL-60 cells; no significant difference between them. DMSO-treated HL-60 cells also responded to interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF), but did not respond to erythropoietin or macrophage colony-stimulating factor, suggesting that the responsiveness of these cells to growth factor is restricted to myelogenic cytokines. In conclusion, DMSO- or RA-treated HL-60 cells are useful for the measurement of bioactivity of hG-CSF.

Animals↗
PubMed1997

Intracisternal injection of opioids induces itch-associated response through mu-opioid receptors in mice.

We examined whether opioids, especially morphine, would centrally elicit scratching in mice and determined some characteristics of the scratch-inducing action of opioids. When intracisternally (i.c.) injected, morphine (0.1-3 nmol/mouse) produced a dose-dependent increase in scratching of the face, but not of the ears, head and body trunk. When injected intradermally into the rostral part of the back, morphine (at most potent i.c. dose of 3 nmol/mouse or higher) did not increase the scratching of the injected site. Facial scratching of the mouse induced by i.c. injection of morphine (0.3 nmol/mouse) was almost abolished by distraction and by naloxone (1 mg/kg, s.c.). [D-Ala2, N-Me-Phe4, Gly5-ol]Enkephalin (DAMGO) (0.03-2 nmol), but not [D-Pen2,5]enkephalin (DPDPE) and U-50,488, dose-dependently elicited facial scratching by i.c. injection. These results suggest that morphine and DAMGO increased facial scratching, probably mediated by central opioid mu-receptors in mice, and such scratching was due to a sensation, probably itching. The present animal model may be useful for analyzing opioid-mediated central itching.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1997

Performance tests of a satellite-based asymmetric communication network for the 'hyper hospital'.

The Hyper Hospital is a prototype networked telemedicine system which uses virtual reality. We measured the performance of a novel multimedia network based on satellite communications. The network was a hybrid system consisting of a satellite channel in one direction and a terrestrial channel in the other. Each user was equipped with a standard satellite communication receiver and a telephone connection. Requests from the users were sent by modern and telephone line and responses were received by satellite. The user requests were initiated by clicking buttons on a World Wide Web browser screen. The transmission rates of satellite and normal telephone-line communications were compared for standardized text data. Satellite communication was three to five times faster. The transmission rate was also measured for standardized graphical data (GIF format). With a file size of about 400 kByte, satellite-mediated communication was 10 times faster than telephone lines. The effect of simultaneous access on performance was also explored. For simultaneous access of nine users to a single graphics file, 78% of the transmission speed was obtained in comparison with that of a single user. The satellite-based system showed excellent high-speed communication performance, particularly for multimedia data.

Hospitals↗
PubMed1997

Systemic idiopathic fibrosis with inflammatory pulmonary lesions.

Systemic idiopathic fibrosis is characterized by non-suppurative inflammatory diseases of connective tissue, mainly adipose tissue. Although, in this condition, fibrosis may develop in several organs, there have been few reports of fibrosis involving the lung or pleura. We present a case of systemic idiopathic fibrosis associated with inflammatory pulmonary lesions, mimicking lung cancer with multiple pulmonary metastases. Chest CT and MRI showed a spiculated mass around the aortic arch with localized aortic wall thickening and nodules in the lungs. Abdominal CT showed a homogeneous mass around the abdominal aorta, consistent with retroperitoneal fibrosis. Transbronchial lung biopsy of the lesion in the right mid-lung field showed only a few scattered histiocytes accompanying inflammatory and fibrotic change. There was no evidence of malignancy, necrosis, angitis or mycobacterial infection. The lesions almost completely disappeared following prednisone treatment.

Aged↗
PubMed1997

Expression of an extracellular calcium-sensing receptor in human and mouse bone marrow cells.

The cloning of a G protein-coupled, extracellular calcium (Ca2+e)-sensing receptor (CaR) from bovine parathyroid provided direct evidence that Ca2+e-sensing can occur through receptor-mediated activation of G proteins and their associated downstream regulators of cellular function. CaR transcripts and protein are present in various tissues of humans and other mammals that are involved in Ca2+e homeostasis, including parathyroid, kidney, and thyroidal C-cells. The present study was performed to determine whether bone marrow cells express the CaR, since cells within the marrow space could be exposed to substantial changes in Ca2+e related to bone turnover. Using DNA and RNA probes from the human parathyroid CaR cDNA, we identified CaR transcripts of 5.2 and approximately 4.0 kilobases by Northern analysis of poly(A+) RNA from low-density mononuclear cells isolated from whole human bone marrow that are putatively enriched in marrow progenitor cells, including bone cell precursors. In situ hybridization also identified CaR transcripts in the same cell preparations. Reverse transcription-polymerase chain reaction demonstrated > 99% nucleotide identity between transcripts from human bone marrow cells and the corresponding regions of the human CaR cDNA. Antisera specific for several different regions within the extracellular domain of the CaR were reactive with low-density human marrow cells that were either adherent or nonadherent to plastic. About one-third of the adherent, CaR-immunoreactive cells were also positive for alkaline phosphatase, a nonspecific marker of preosteoblasts, osteoblasts, and assorted cells of the colony-forming unit-fibroblast lineage. In addition, a substantial fraction (approximately 60%) of low density murine marrow cells cultured for 1 week at 4.8 mM Ca2+e expressed both CaR immunoreactivity and nonspecific esterase, an enzyme expressed by monocyte/macrophages and fibroblasts. Finally, erythroid precursors and megakaryocytes from murine marrow as well as blood platelets expressed abundant CaR immunoreactivity, while peripheral blood erythrocytes and most polymorphonuclear leukocytes did not. These studies indicate that the CaR is present in low-density mononuclear bone marrow cells as well as in cells of several hematopoietic lineages and could potentially play a role in controlling the function of various cell types within the marrow space.

Animals↗
PubMed1997

A study on the biological significance of midregion and intact parathyroid hormone in hemodialysis patients.

In this study, we investigated the relationship between the concentrations of intact parathyroid hormone (i-PTH) and midregion PTH (m-PTH) measured by an immunoradiometric assay and a radioimmunoassay, respectively, versus various demographic and biochemical parameters, bone mineral density (BMD) of the lumbar spine (LS) and radius, and the radiographic findings of osteosclerosis and aortic calcification in hemodialysis (HD) patients. m-PTH correlated positively and more significantly with serum calcium (Ca), serum phosphorus (P), Ca-P solubility products (Ca x P) and LS-BMD than i-PTH did (P = 0.024 vs. 0.531, 0.001 vs. 0.061, 0.0001 vs. 0.125, and 0.017 vs. 0.284, respectively). A positive correlation between the percent changes in serum P over the 1-month measurement period and those in m-PTH rather than in i-PTH was also observed (P = 0.021 vs. 0.869). These data indicate than m-PTH is distinct from i-PTH in its positive correlation with serum Ca, serum P, Ca [symbol: see text] P and LS-BMD in HD patients. Since m-PTH is known to consist mostly of the midregion and carboxyl-terminal fragments of PTH in HD patients, the present study suggests that these PTH fragments may be biologically significant in the patients in vivo.

Adult↗
PubMed1997

Effect of serum amyloid A on cellular affinity of low density lipoprotein.

Serum amyloid A, an apolipoprotein of high density lipoproteins, is also present to a lesser degree in low density lipoproteins and is co-localized with apolipoprotein B in atherosclerotic lesions. This study examined the effect of serum amyloid A on cellular affinity of low density lipoprotein in vitro. 125I-labelled low density lipoprotein, when loaded with recombinant serum amyloid A1 (acute phase isotype) or recombinant serum amyloid A4 (constitutive isotype), had enhanced binding to both human skin fibroblasts and a murine macrophage cell line, J774, while its degradation was slightly increased in both cells. The binding of oxidized low density lipoprotein to J774 cells was also enhanced by addition of recombinant serum amyloid A1 or serum amyloid A4, and degradation of oxidized low density lipoprotein was moderately enhanced by recombinant serum amyloid A1. The effects of recombinant serum amyloid A on cellular binding of labelled low density lipoprotein were not competed by non-labelled low density lipoprotein and were diminished in the presence of high density lipoprotein. These findings suggest that serum amyloid A in low density lipoprotein may promote association of low density lipoprotein with cells by non-specific adsorption, and high density lipoprotein may prevent such interactions by removal of serum amyloid A.

Adult↗
PubMed1997

Patency of intermediate size side branches after Palmaz-Schatz stent implantation.

The immediate and long-term patency of intermediate size side branches was assessed by serial coronary angiography in 47 patients with 48 lesions to determine whether the presence of these side branches (1-2 mm in diameter) is unsuitable for Palmaz-Schatz stent implantation. Coronary angiography was performed at baseline, after conventional balloon angioplasty, immediately after stent implantation, at 1 week, and at 6-month follow-up. Sixty-eight lesion-associated side branches that were 1-2 mm in diameter, 11 with branch ostial stenosis (Group A) and 57 without ostial stenosis (Group B) were studied. After stent implantation, 9 (13%) branches became totally occluded and coronary flow deteriorated in 13 branches (19%). The incidence of side branch occlusion during the procedure in group A was greater than in group B (55% vs. 12%; p < 0.005). One (2%) patient suffered persistent chest pain, but no procedure was complicated by Q-wave myocardial infarction or significant elevation of creatine kinase concentration. Flow improved in 82% of the occluded side branches after 1 week and in 90% after 6 months. These results suggest that the presence of intermediate size side branches is not a contra-indication to Palmaz-Schatz stent implantation.

Angioplasty, Balloon, Coronary↗
PubMed1997

Use of an osseointegrated implant for dental rehabilitation after cleft repair by periosteoplasty: a case report.

OBJECTIVE: We report here on a patient with unilateral cleft lip and alveolus who underwent dental rehabilitation of cleft alveolus using an osseointegrated implant after cleft repair by periosteoplasty. The patient, whose lateral incisor was congenitally missing, had periosteoplasty, followed by excellent bone formation at the cleft alveolus within 2 years. After the completion of orthodontic alignment of the maxillary dental arch, a Brånemark single-tooth implant was placed into the bone-formed alveolus. CONCLUSION: This treatment procedure offers an option of dental rehabilitation for the alveolar clefts of patients with cleft lip and/or palate.

Alveolar Process↗
PubMed1997

Serum levels of soluble Fas/APO-1 receptor in human retroviral infection and associated diseases.

Fas/APO-1 mediates apoptosis via Fas and Fas ligand transduction. Recently, a soluble form of Fas (sFas) was described which seems to be functionally implicated in the Fas signal system, suggesting a relationship between some disorders and sFas function. We measured sFas-levels in sera from normal controls and patients with disorders linked to human retroviral infection of human immunodeficiency virus (HIV) and human T-cell leukemia virus type-1 (HTLV-1). The sFas level of normal controls. HTLV-1 carriers seronegative for HIV, and patients with HTLV-1 associated myelopathy/tropical paraparesis (HAM/TSP), adult T-cell leukemia (ATL), and AIDS was 1.62 +/- 0.49, 1.90 +/- 0.49, 2.00 +/- 0.59, 3.32 +/- 2.05, and 3.06 +/- 0.92 ng/ml, respectively. Although the level of sFas in patient groups with HAM/TSP, ATL, and AIDS was significantly high in comparison to that of normal controls (p < 0.01), the individual values were highly variable within the groups. The sFas level was statistically correlated to the soluble interleukin-2 receptor (sIL-2R) level, as well as to cells expressing membrane Fas (mFas), indicating the same cellular origin. In some ATL cases, however, serum sFas levels and mFas expression density on leukemic T-cells were discrepant, with especially high levels of the soluble form and a lack of expression of the membrane form observed in 2 cases, sFas detection could serve as a putative marker for active diseases in patients with ATL and AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1997

High-pressure-induced hemolysis of hereditary spherocytic erythrocytes is not suppressed by DIDS labeling.

Hemolytic properties of human erythrocytes in hereditary spherocytosis (HS) were examined under hydrostatic pressure or hypotonic conditions. In the hypotonic buffer, HS erythrocytes were more fragile than normal erythrocytes, and the osmotic fragility was similarly enhanced if both erythrocytes were treated with 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS), an anion transport inhibitor. On the other hand, the hemolysis of HS erythrocytes at 200 MPa was almost the same degree as that of normal cells. Upon DIDS treatment, the hemolysis of normal erythrocytes at 200 MPa was suppressed by about 35%, whereas that of HS erythrocytes was not affected. The absence of a suppressive effect of DIDS on high-pressure-induced hemolysis is likely to be HS-specific and may be a reflection of the underlying defects of band 3-cytoskeleton interactions in HS erythrocytes.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1997

Hyper Hospital on the satellite multi-media network.

We have been developing the Hyper Hospital, a network based VR mediated medical care system. The Hyper Hospital is composed of two seamlessly integrated environments, that is, the virtual and the real worlds. Of them, its virtual environment expands the conventional medical care system using the virtual reality technology as a principal human interface and a collaboration tool, in the present study, an attempt to extend the Hyper Hospital system to various modalities of communication network is reported. A satellite communication based multi-media network using Internet protocols with the WWW interface is used. Data transmission rate and other performances were measured under various conditions and the satellite network was shown to be suitable to the Hyper Hospital network.

Computer Communication Networks↗
PubMed1997

Comparison of in vitro carnitine and glycine conjugation with branched-side chain and cyclic side chain carboxylic acids in rats.

The substrate specificity for carnitine conjugation was examined using rat hepatocytes and kidney slices and compared with glycine conjugation which is a competitive pathway through the CoA thioester. For both hepatocytes and kidney slices, the best substrate for the camitine conjugate was cyclopropanecarboxylic acid followed by cyclobuthanecarboxylic acid (CBCA) and cyclohexanecarboxylic acid (CHCA). For the glycine conjugate, the best substrate was benzoic acid, with conjugation also occurring with CHCA and CBCA. These results suggest that carnitine transferase shows substrate specificity for cyclic side chain carboxylic acids of lesser carbon number, while glycine transferase shows inverse specificity. To compare directly the amounts of carnitine and glycine conjugates in the liver and the kidney, we estimated the endogenous amounts of carnitine and glycine and then multiplied the results by the production ratio of each conjugate. With respect to the enzyme activity per unit tissue weight, the kidney tended to show higher activities for both conjugates than the hepatocytes. This is the first report, to our knowledge, of the kidney having high carnitine conjugation activity. Cyclopentanecarboxylic acid (CPECA) was the least effective substrate for glycine and carnitine conjugates in both hepatocytes and kidney slices, CPECA may not readily undergo esterification with CoA. The branched-side chain carboxylic acids, such as pivalic acid (PA) and isobutylic acid, were also poor substrates for carnitine and glycine conjugates in rat hepatocytes and kidney slices.

Animals↗
PubMed1997

[Diagnostic imaging of renal pedicle injury].

We reviewed the radiological findings of 8 patients with renal pedicle injury admitted to our emergency center from January 1986 through September 1995 and compared them with the previously reported findings. The patients included 3 with renal artery occlusion and 5 with avulsion or disruption of renal pedicle vasculature. Extended retroperitoneal hematoma such as contralateral pararenal or central parahilar hematoma was visualized in all 5 cases with avulsion or disruption of renal pedicle vasculature. Although lack of contrast enhancement of injured renal parenchyma is a hall-mark of renal pedicle injury, three cases did not demonstrate this typical finding. In these three cases, one showed partial and the others showed total enhancement of the injured renal parenchyma on contrast enhanced CT. Partial enhancement in one case was found to represent total occlusion of the main renal artery and an intact accessory polar branch on angiography. The other two cases showed total enhancement of the renal parenchyma, with renal vein perforation done and complete disruption of the main renal artery and vein in the other. The latter findings were thought to be due to the maintenance of vascular flow surrounded by hematoma. In conclusion, when central parahilar hematoma is identified, the possibility of renal pedicle injury should be considered even if the renal parenchyma is well enhanced.

Adolescent↗
PubMed1997

[A case of pleural metastasis of invasive thymoma with pulmonary metastasis responding to chemotherapy with cyclophosphamide and prednisolone].

The patient, a 48-year old male, was seen with hoarseness in December 1990. A chest radiograph and chest CT scan showed an anterior mediastinal mass. Median sternotomy revealed epithelial thymoma with involved partial lung and pericardium. After surgery, he received external radiation to the mediastinum. One year later he was given another 40 Gy external radiation in the cervical and mediastinal recurrence region. In May 1994, a chest CT scan revealed an extrapleural and bilateral lung mass. Histological examination revealed recurrent epithelial thymoma in the left cervical muscle biopsy, so treatment with cyclophosphamide and prednisolone were begun. A dose of 100 mg/body/day of cyclophosphamide and a dose of 10 mg/body/day of prednisolone were administered every 2 week. Complete remission was induced with four cycles of this treatment of cyclophosphamide and prednisolone. The chemotherapy was thus continued for 20 cycles in 14 months. This chemotherapy with cyclophosphamide and prednisolone appeared to be useful and safe for recurrent thymoma at the outpatient clinic level.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

[Short-term intensive treatment for acute myelogenous leukemia (excluding M3 subtype) in adults].

Thirty-two adults (median age 48 years) with acute myelogenous leukemia (excluding M3) have been treated with short-term intensive therapy (M90 therapy). After induction therapy with daunorubicin, cytosine arabinoside (araC), 6-mercaptopurine, prednisolone, mitoxantrone (MIT) and etoposide (VP16), three regimens of post-induction chemotherapy were conducted as short an intercycle time as possible. The first regimen was with MIT and VP16, the second with behenoyl-araC and aclarubicin and the third with VP16, araC, vincristine and vinblastine. No further therapy was given. Complete remission was achieved in 24 (75%) of 32 patients and 24% of all patients were projected to remain free of disease at 5 years. The median duration of the entire therapy was 120 days with a range of 95 to 157 days. Post-induction regimens resulted in severe myelosuppression and their toxicity included treatment-related death in one patient. The treatment results of this short-term therapy were comparable to a former treatment protocol, M84 therapy with a median duration of the entire treatment therapy of 515 days. To confirm the advantages of such short-term therapy, prospective randomized comparisons with conventional post-induction therapy may be required.

Aclarubicin↗