Biomedical subjects

H Miyamoto

Publications and source records attributed to H Miyamoto.

At least 19 recordsLinked to original sources

PubMed1992

Different patterns of cell volume regulation in hyposmotic media between attached and suspended HeLa cells.

Both attached and suspended HeLa cells swelled in a medium of a hypotonic osmolality of 235 mosmol/kg H2O. When the osmolality was further decreased to 166 mosmol/kg H2O, attached cells instantly swelled and then rapidly lost water and K+, followed by slow gains of them. Suspended cells instantly swelled and then K+ loss and regulatory volume decrease (RVD) occurred. Neither 0.1 mM ouabain nor 10 mM TEA changed the water loss of attached cells, whereas ouabain inhibited RVD of suspended cells. Quinine (1 mM) inhibited water losses from both cells and comparison of the losses implies stronger activation of K+ channel in attached cells than in suspended cells. Omission of medium Ca2+ or addition of 10 mM BaCl2 inhibited RVD in part. These results suggest that hyposmotic stress induces net water loss from attached cells, associated with K+ release through the Ca(2+)-dependent K+ channel. Suspended cells osmotically swell, followed by RVD with K+ and Na+ releases through the K+ channel and Na(+)-pump, respectively. The different patterns of volume changes may relate to the difference of activity or time of activation of the K+ channel between both cells.

Barium↗

PubMed1992

Structure and expression of the gene encoding mouse t-complex polypeptide (Tcp-1).

The nucleotide (nt) sequence of the structural gene (Tcp-1) encoding mouse t-complex polypeptide 1 (TCP-1) has been determined. The nt sequence extending to 10,043 bp shows that the Tcp-1 gene is divided into 12 exons, 11 introns and 5'- and 3'-flanking regions. The Tcp-1 gene has a tight cluster of major transcription start points (tsp). Two GC boxes, one CCAAT box and some other possible regulatory elements are located in the region upstream from the tsp, but no TATA box was found. Extending from the 5'-flanking region to the first intron, a CpG dinucleotide-rich cluster is located. In addition, Tcp-1 gene transcripts in mouse organs, embryos and cultured cells were analyzed by Northern blotting. The Tcp-1 mRNA is enriched not only in testes, but also in early post-implantation embryos and some cultured cell lines, as compared with mouse organs other than the testis. The amount of Tcp-1 mRNA in embryos decreases during development. These results suggest that the expression of the Tcp-1 gene may be regulated spatially and temporally in embryonic and adult mice by transcriptional control or by mRNA stability.

Amino Acid Sequence↗

PubMed1992

Growth of human cultured cells exposed to a non-homogeneous static magnetic field generated by Sm-Co magnets.

A static magnetic field, with a strong spatial gradient, was established on the surface of cell culture dishes by use of a gilded iron needle set vertically above an Sm-Co magnet. The calculated magnetic flux density was more than 1.5 T at the center of the needle tip, and the products of the flux density and its gradient were about 200 and 60 T2/m at distances of 0.1 and 0.3 mm, respectively, from the center. The DNA content, DNA synthesis and labeling index of cultured cells located within 0.1 mm from the center of the needle, and the growth rate of cells located within 0.3 mm from the center, were measured. HeLa cells grew at a normal rate for 96 h in the magnetic field and showed no significant change in shape, detectable by scanning electron microscopy. The growth of HeLa cells was not influenced by exposure to the magnetic field. Similarly, exposure for 48 h to the magnetic field had no effect on growth of normal human gingival fibroblasts (Gin-1). The DNA content, assayed by microfluorometry of the nuclei of both types of cells stained by the Feulgen reaction, was not significantly different from that of controls. Moreover, exposure to the magnetic field had no effect on DNA synthesis or the labeling index of HeLa cells assayed by autoradiography of incorporated [3H]thymidine. It is concluded that a non-homogeneous magnetic field of the intensity and the gradient used in this study does not significantly influence the growth of HeLa cells or Gin-1 cells.

Cells, Cultured↗

PubMed1992

Reduced drug accumulation in a newly established human lung squamous-carcinoma cell line resistant to cis-diamminedichloroplatinum(II).

A human lung squamous-carcinoma cell line resistant to cis-diamminedichloroplatinum(II) (CDDP), designated PC10-B3, has been established from the original cell line PC10 by a stepwise increment of the CDDP concentration. This is the first report, to our knowledge, to establish a CDDP-resistant lung squamous-carcinoma cell line. PC10-B3 has continued to proliferate in the presence of 0.5 micrograms/mL CDDP, whereas PC10 could not survive. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that PC10-B3 was 11.4-fold more resistant to CDDP than PC10 and cross-resistant to diammine(1,1-cyclobutanecarboxylate)platinum(II) (CBDCA) and 254-S, but not to doxorubicin or etoposide. PC10-B3 was characterized by a smaller DNA index and a larger cell size compared to PC10. The level of intracellular platinum accumulation was reduced by about 5- to 8-fold in PC10-B3 when compared with PC10, suggesting that reduced drug accumulation may be one of the important factors in contributing to CDDP resistance in PC10-B3.

Carcinoma, Squamous Cell↗

PubMed1992

Genomic structure of the ME491/CD63 antigen gene and functional analysis of the 5'-flanking regulatory sequences.

Genomic structure of the ME491/CD63 antigen gene and promoter activity of the 5'-flanking regulatory sequences were studied. The antigen gene consists of eight exons that span 4 kilobase-pairs. Primer extension analysis with RNA from cultured human cells identified three major transcription initiation sites. The 5'-flanking region of exon 1 has features characteristic to promoters of many house-keeping genes and growth-regulating genes. The region is highly GC rich and contains potential binding sites for transcription factors such as Sp1 and ETF, but not a TATA box. The 5'-flanking sequence exerted strong promoter activity when linked to a reporter gene. Deletion mutant analysis of the 5'-flanking sequence has strongly suggested that a potential binding site for AP-1 plays an important role in positively regulating the gene expression.

Amino Acid Sequence↗

PubMed1992

Prognostic significance of the expression of ras oncogene product in non-small cell lung cancer.

The clinical significance of ras oncogene expression in non-small cell lung cancer was evaluated in 116 surgically treated patients. Archival paraffin sections of the tumors were analyzed immunohistochemically using anti-ras p21 monoclonal antibody (MoAb) rp-35, and p21 staining was correlated with clinicopathologic parameters and survival. Positive reactions (+ and ++) were observed in 72.5% of the adenocarcinomas and 55.6% of the squamous cell carcinomas studied. The T1 tumors showed a ++ reaction less frequently than T2 and T3 tumors (P less than 0.05). Stage I tumors also were less reactive with MoAb rp-35 than tumors in more advanced stages (P less than 0.05). Survival analysis showed that patients with p21-negative tumors had significantly longer survival times (a 5-year survival rate of 64.1%) than those with p21 + tumors (38.0%, P less than 0.05) or those with p21 ++ tumors (11.5%, P less than 0.005). The significant correlation between p21 staining and patient survival was independent of histologic type, stage of disease, tumor or node status, and the resectability of tumors. On Cox's multivariate analysis, p21 staining was a major and independent prognostic determinant of survival. These results suggest that enhanced ras p21 expression may be one of the important biologic and clinical markers indicating the malignant potential of non-small cell lung cancer.

Carcinoma, Non-Small-Cell Lung↗

PubMed1992

Accuracy of the bronchoscopic DNA content analysis of non-small-cell lung carcinoma.

To assess the accuracy of the bronchoscopic DNA content analysis, samples of non-small-cell lung carcinomas (NSCLC) were investigated by means of flow cytometry. Samples were dissociated using the detergent Triton X-100. In 58 NSCLC cases, 39 (67%) had DNA aneuploid tumors. We compared the DNA indices of bronchoscopic brushing samples with 21 corresponding surgical samples. In 16 (76%) cases, DNA ploidy of both bronchoscopic and surgical samples were in concordance. In 3 (14%) cases, both bronchoscopic and surgical sample showed DNA aneuploidy, but the number of the DNA aneuploid stem cell lines was different. The cause of these differences was ascribed to the intratumor DNA heterogeneity. In 2 (10%) cases, the bronchoscopic sample showed DNA diploidy, but the surgical sample showed DNA aneuploidy. In these cases, tumor cells obtained by bronchoscopic brushing were so few that the small DNA aneuploid peak was undetectable in the DNA histogram. But the tumor DNA ploidy was evaluated correctly in 90% of 21 cases using bronchoscopic samples. Consequently, despite some drawbacks, the DNA ploidy diagnosis using bronchoscopic samples in this relatively small study, was almost as reliable as surgical samples.

Adenocarcinoma↗

PubMed1992

Changes in the concentrations of Na+, K+ and Cl- in secretion from the skin during progressive increase in exercise intensity.

A simple method for sampling skin secretion in 1-min periods was developed for investigating the effects of progressive increases in exercise intensity on Na+, K+ and Cl- secretions from the skin of the forearm. Ten healthy male subjects performed exercise consisting of eight stepwise increases in intensity from 50 to 225 W, with a 25-W increase at each step. Exercise at each step was for 3 min followed by a 1-min recovery period. Samples of blood and skin secretion were taken during the recovery period. Significant positive correlations were found between the mean concentrations of Na+ and Cl- and between those of K+ and Cl- in the skin secretion. The concentrations of electrolytes in the skin secretion also showed significant correlations with the blood lactate concentrations. The inflection points for secretions of Na+, K+ and Cl- were 4.04, 3.61 and 3.83 mmol.l-1 of blood lactate; 64.42, 61.96 and 62.14% of maximal oxygen consumption (VO2max); and exercise intensities of 123.01, 117.65 and 125.07 W, respectively. No significant differences were observed between the value of 67.27% of VO2max or 134.00W at the onset of blood lactate accumulation (OBLA) and the inflection points. From these results we concluded that changes in electrolyte concentrations in skin secretion during incremental exercise according to this protocol were closely related with the change in the blood lactate concentration, and that the inflection points for electrolytes may have been near the exercise intensity at OBLA.

Adult↗

PubMed1992

Construction of a thermotaxis chamber providing spatial or temporal thermal gradients monitored by an infrared video camera system.

A thermotaxis chamber was constructed to quantitatively study thermotaxis in eukaryotic amoeboid cells. The apparatus provided either spatial or temporal temperature gradients in an observation chamber set in an inverted microscope. With an infrared video camera system, spatial thermal gradients were monitored directly and the temperature at the actual location of the cells could be estimated accurately. This enabled a precise determination of the strength of thermal stimuli. With this apparatus, we were able to simultaneously measure temperature and observe cellular behavior directly. This feature permits quantitative studies on stimulus-response relationships. The utility of the apparatus was demonstrated by thermotaxis assay under a spatial thermal gradient in polymorphonuclear leukocytes. Since this apparatus can also provide temporal thermal gradients, it may have several applications in studies of temperature-dependent phenomena in cell biology.

Amoeba↗

PubMed1992

Extraordinarily low density of hepatitis C virus estimated by sucrose density gradient centrifugation and the polymerase chain reaction.

The genomic RNA of hepatitis C virus (HCV) in the plasma of volunteer blood donors was detected by using the polymerase chain reaction in a fraction of density 1.08 g/ml from sucrose density gradient equilibrium centrifugation. When the fraction was treated with the detergent NP40 and recentrifuged in sucrose, the HCV RNA banded at 1.25 g/ml. Assuming that NP40 removed a lipid-rich surface coat from HCV, the 1.08 g/ml and 1.25 g/ml HCV RNA may correspond to intact HCV virions and nucleocapsids, respectively. The extraordinarily low density of the virion is unusual in comparison to the density of classified viruses.

Base Sequence↗

PubMed1992

Angiosarcoma of the thigh with thrombosis in the femoral artery.

We report a case of angiosarcoma with some peculiar clinical features developing on the left thigh of a 63-year-old man. The early primary lesion was erythematous with necrotic areas. The initial biopsy specimen of the lesion indicated a benign angioproliferative process. However, the necrotic area enlarged rapidly, ulcerated with severe pain, and thus was widely excised. The excised specimen had a malignant histologic appearance, particularly in the fascia, and was diagnosed as angiosarcoma. Following local recurrence, the lesion was complicated by thrombosis of the femoral artery at the affected site. A similar cutaneous lesion subsequently arose on the right lower leg, and thrombosis developed in the right femoral artery. Both legs had to be amputated. There were no distant metastases.

Amputation, Surgical↗

PubMed1992

Auditory brain stem response (ABR) in anorexia nervosa.

Auditory brain stem responses were recorded in 20 patients with anorexia nervosa and 10 normal control subjects. Twenty patients were studied during two phases of illness, 1) anorexia nervosa group with under weight (U-AN group), and 2) anorexia nervosa group with recovered normal weight (N-AN group). Absolute latencies, interwave latencies, absolute amplitudes, and amplitude ratios were investigated. A nonsignificant difference was found among these groups as far as the latencies were concerned. Both the patients in the U-AN group and those in the N-AN group had significantly smaller amplitude ratios (III/I, IV.V/I) and absolute amplitude (V) than did the control subjects. Furthermore, a nonsignificant difference was found between the U-AN group and the N-AN group. It suggests that some dysfunction might exist in the region of the brain stem.

Adolescent↗

PubMed1992

A long-term observation on a case of epilepsy with occipital continuous spikes.

We have reported a 38-year-old female who did not show clinical seizures during continuous spikes in the left occipital area over a period of 18 years. As to the neurological findings, visual disturbance, optic nerve atrophy and right hemianopsia were almost always present. The low density area distributing from the left occipital area to the left temporal one on the CT revealed to be porencephaly. From the clinical findings obtained in this case, the lesion responsible for the occipital continuous spikes could be ascribed to be functional abnormality of the visual pathway connecting the left lateral geniculate body with the left occipital cortex.

Adult↗

PubMed1992

Characterization of a novel aquaretic agent, OPC-31260, as an orally effective, nonpeptide vasopressin V2 receptor antagonist.

1. OPC-31260, a benzazepine derivative, has been studied for its ability to antagonize the binding of arginine vasopressin (AVP) to receptors in rat liver (V1) and kidney (V2) plasma membranes, for antagonism of the antidiuretic action of AVP in alcohol-anaesthetized rats and for diuretic action in conscious normal rats. 2. OPC-31260 caused a competitive displacement of [3H]-AVP binding to both V1 and V2 receptors with IC50 values of 1.2 +/- 0.2 x 10(-6) M and 1.4 +/- 0.2 x 10(-8) M, respectively. 3. OPC-31260 at doses of 10 to 100 micrograms kg-1, i.v., inhibited the antidiuretic action of exogenously administered AVP in water-loaded, alcohol-anaesthetized rats in a dose-dependent manner. OPC-31260 did not exert an antidiuretic activity suggesting that it is not a partial V2 receptor agonist. 4. After oral administration at doses of 1 to 30 mg kg-1 in normal conscious rats, OPC-31260 dose-dependently increased urine flow and decreased urine osmolality. The diuretic action of OPC-31260 was characterized as aquaresis, the mode of diuretic action being different from previously known diuretic agents such as furosemide, hydrochlorothiazide and spironolactone. 5. The results indicate that OPC-31260 is a selective V2 receptor antagonist and behaves as an aquaretic agent. OPC-31260 will be a useful tool in studying the physiological role of AVP and in the treatment of various conditions characterized by water retention.

Administration, Oral↗

PubMed1992

Investigation of the role of macrophages and endogenous interferon-gamma in natural resistance of mice against Legionella pneumophila infection.

Mice are highly resistant to Legionella pneumophila infection. To study the natural resistance, we used A/J and C57BL/6 mice which have macrophages permissive and non-permissive for the intracellular growth of L. pneumophila, respectively. The LD50 for A/J and C57BL/6 were 2.7 x 10(7) and 7.2 x 10(7) CFU, respectively, indicating that the difference in macrophage ability to regulate the bacterial growth had some effect on susceptibility to L. pneumophila. There was no difference between both strains in elimination of the bacteria from the blood stream within 5 h after infection. When mice were challenged intravenously with a sublethal dose (4 x 10(6) CFU), the bacterial burden in the liver at day 1 was significantly higher in A/J than in C57BL/6. The bacteria, thereafter, were eliminated rapidly from the liver at a similar rate in both strains. Elimination of the bacteria from the spleen and lungs was also delayed in A/J as compared to C57BL/6. Naive spleen cells of both strains in vitro could produce a large amount of interferon-gamma (IFN-gamma) one day after they were stimulated with formalin-killed L. pneumophila. When anti-murine IFN-gamma monoclonal antibody was administered, the bacterial burden in liver, spleen and lungs significantly increased in A/J, and also in C57BL/6 to some extent. We suggest that the innate macrophages' ability to regulate the intracellular bacterial growth and the endogenous IFN-gamma produced in a very early phase play a critical role in murine natural resistance against L. pneumophila infection.

Animals↗

PubMed1992

Adult T-cell leukemia/lymphoma (ATL)--clinical, histopathological, immunological and immunohistochemical characteristics.

Twenty-one patients with ATL were assessed. The predominant physical findings were lymph node and bone marrow involvement, skin involvement, hepatosplenomegaly and leukemic manifestations. The predominant histopathological findings in both skin and lymph node specimens were the diffuse medium-sized cell type and the diffuse mixed cell type. Some phenotypic discrepancy was found between the neoplastic cells in the peripheral blood, lymph nodes and skin of patients with ATL with respect to CD45RA and CD45RO, and CD7, CD29, CD25 and HLA-DR. That is, the predominant neoplastic cell phenotype was the helper T-cell, which was CD3+, CD4+, CD7+, CD25+, CD45RA+ and HLA-DR+, and CD29- and CD45RO- in peripheral blood and lymph nodes, and CD3+, CD4+, CD7+, CD29+, CD45RO+ and HLA-DR+, and CD45RA- in the skin. In other words, we have described the phenotypic heterogeneity of ATL cells and demonstrated the heterogeneity of CD45R isoform expression on ATL cells in different organs--the skin, peripheral blood and lymph nodes--of the same patient.

Adult↗

PubMed1992

A phase III comparison of etoposide/cisplatin with or without added ifosfamide in small-cell lung cancer.

A total of 92 patients with small-cell lung cancer (SCLC) were randomized to receive cisplatin (80 mg/m2, day 1)/etoposide (100 mg/m2, days 1, 3, 5) (PE) or cisplatin (80 mg/m2, day 1)/etoposide (100 mg/m2, days 1, 3, 5)/ifosfamide (2 g/m2, days 1, 2, 3) (PEI) combination chemotherapy. After 2 courses of chemotherapy, patients with limited disease (LD) received chest irradiation of 40-50 Gy. Of the 89 patients who could be wholly evaluated, the overall response rate was 78% for PE and 74% for PEI therapy (NS). For all patients the complete response (CR) rates were 14 versus 21%, respectively, and 22 versus 30% for LD. However, the median survival times for all patients were 55 weeks for PE therapy versus 56 weeks for PEI therapy (NS). The 2-year survival rates were 15 and 17%, respectively, for all patients (NS). There was no difference in the duration of response between PE and PEI therapy in cases with CR or partial response. However, severe leukopenia (< 2,000/mm3) occurred more often after PEI (73%) than after PE (44%) therapy (p < 0.05). These results suggest that PEI is not superior to PE chemotherapy in SCLC. The use of ifosfamide in multimodality treatment regimens needs to be studied further.

Adult↗

PubMed1992

Bellini duct carcinoma of the kidney.

We report a very rare case of Bellini duct carcinoma originating from the collecting tubules of the kidney. A left renal tumor was detected during a health examination and radical nephrectomy was performed. Histological examination showed papillary adenocarcinoma. By means of immunohistochemical methods, we felt that the tumor was a renal carcinoma of Bellini duct origin.

Adenocarcinoma, Papillary↗