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Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 487 records · Page 27Linked to original sources
PubMed1994

Messenger RNA levels of five genes located at chromosome 11q13 in B-cell tumors with chromosome translocation t(11;14)(q13;q32).

To identify genes activated by chromosome translocation t(11;14)(q13;q32), mRNA levels of five genes (cyclin D1, EXP1, MB38, HST1, and INT2) at chromosome 11q13 were investigated. The cyclin D1 mRNA increased in BCL-1-rearranged B-cell tumor cell lines SP-49, NOP-2, FLAM-76, KMS-12-PE, and KMS-12-BM cells, while it was not detected in cell lines without the translocation, Raji, U266, and HEL cells. A significant amount of the MB38 mRNA was detected irrelevantly to the translocation in all of these cell lines. The mRNAs of EXP1, HST1, and INT2 were undetectable in these cells. The results suggested that the translocation activates cyclin D1 alone, while the mRNA levels of the other four genes are regulated independently of the translocation.

Blotting, Northern↗
PubMed1994

Preferential expression of the third immunoglobulin-like domain of K-sam product provides keratinocyte growth factor-dependent growth in carcinoma cell lines.

Previously, we identified an amplified gene in a stomach cancer cell line, KATO-III, and designated it K-sam. This gene was later found to be identical with a gene for a receptor tyrosine kinase, bek/FGFR2. One of the characteristics of the K-sam gene is structural diversity of its transcripts; K-sam complementary DNA (cDNA) cloned from human brain (K-sam-I) has a completely different sequence at the third extracellular immunoglobulin-like domain as compared to that of the K-sam cDNA derived from KATO-III cells (K-sam-II). Recent study has revealed that this difference signifies a differential ligand affinity; the receptor encoded by the K-sam-I cDNA has a high affinity for basic fibroblast growth factor (bFGF), while the K-sam-II cDNA corresponds to a receptor with the high affinity for keratinocyte growth factor (KGF). Reverse transcription-polymerase chain reaction and RNA blot analysis showed that the K-sam-II-type transcript was present in carcinoma cell lines but not in any of the sarcoma cell lines examined. The K-sam-I-type transcript was expressed in both carcinoma and sarcoma cell lines. Furthermore, KGF enhanced the DNA synthesis of the esophageal cancer cells, TE-1, in a dose-dependent manner, while the effect of bFGF was not substantial. In contrast, the glioblastoma cell line, A-172, that expressed the bFGF receptor showed a mitogenic response to bFGF but not to KGF. These data suggest that KGF is a growth factor used preferentially in cancer cells, and this preference is based on the presence of the K-sam-II-type receptor in carcinoma cells but not in sarcoma cells due to alternative splicing.

Base Sequence↗
PubMed1994

Evaluation of testicular germ cell tumor proliferation using DNA flow cytometry and nucleolar organizer silver staining.

We studied 41 testicular germ cell tumors (TGCT) using DNA flow cytometry and argyrophilic (silver staining) nucleolar organizer region (Ag-NOR) quantitation to evaluate the proliferative characteristics of TGCT and the significance of those analytical techniques. In nonseminomatous germ cell tumor (NSGCT), the percentage of S + G2M phase cells (%S + G2M) in DNA aneuploid tumor was higher than in DNA of diploid tumors. Likewise, in NSGCT the aneuploid Ag-NOR sites per nucleus (Ag-NOR count) were significantly higher in DNA aneuploid than in DNA diploid tumors. There was also a significant linear correlation between % S + G2M phase cells and the Ag-NOR count in TGCT. However, the DNA ploidy pattern and the % S + G2M phase cells, and Ag-NOR counts, did not correlate significantly with the patient survival rate or clinical stage. In conclusion, our study suggests that Ag-NOR enumeration is an effective technique for assessing cellular proliferative activity that is somewhat less expensive than DNA flow cytometry.

Cell Division↗
PubMed1994

Arrangement and innervation of the glutei medius and minimus and the piriformis: a morphological analysis.

In order to examine the relationships between the positional arrangement and supplying nerves of the glutei medius and minimus and the piriformis, we investigated 49 pelvic halves of 28 cadavers. The superior gluteal nerve ran on the ventral surface of the piriformis in 44 cases (89.8%) (Type A), and some branches of the nerve perforated the piriformis in five cases (10.2%) (Type B). Based on the detailed findings of the innervation of the three muscles, the piriformis is chiefly composed of the caudal element of the gluteus medius (Type A) and in some cases the caudal element of the gluteus minimus as well (Type B).

Female↗
PubMed1994

A correlation of argyrophilic nucleolar organizer regions with prognoses in patients with maxillary sinus squamous cell carcinoma.

Argyrophilic nucleolar organizer regions (AgNORs) were determined by a semiautomatic image analyzer in a group of 28 patients with T2 or T3 maxillary sinus squamous cell carcinoma. The group was separated into recurrent and non-recurrent groups, metastatic and non-metastatic groups, as well as groups strongly or weakly positive for epidermal growth factor receptor (EGFR). The mean number and area of AgNOR dots per nucleus and the mean size of each dot were calculated. The mean number and area were significantly greater than those in normal cells (P < 0.001), but not in recurrent and non-recurrent groups, metastatic and non-metastatic groups and groups separated by EGFR. There was also no difference found in the mean sizes of tumor and normal cells. These results suggest that AgNOR is related to malignant transformation, but not prognosis.

Aged↗
PubMed1994

Non-P-glycoprotein-mediated multidrug-resistant human KB cells selected in medium containing adriamycin, cepharanthine, and mezerein.

Human epidermoid KB cell lines resistant to high levels of adriamycin, C-A90, C-A120, C-A500, and C-A1000, were isolated in selection medium containing increasing concentrations of adriamycin, 1 microgram/ml of cepharanthine, a multidrug-resistance (MDR) reversing agent, and 100 nM of mezerein, a protein kinase C activating agent. One of the adriamycin-resistant KB cell lines, C-A500, was cross-resistant to drugs that typify the classical multidrug resistance phenotype, such as vincristine, actinomycin D, VP-16, and colchicine. The accumulation of adriamycin and vincristine was decreased in C-A500 cells and the efflux of adriamycin from C-A500 was enhanced compared with parental KB-3-1 cells. These adriamycin-resistant KB cells did not contain detectable levels of P-glycoprotein or overexpress MDR1. Multidrug-resistance-associated protein (MRP) and MRP mRNA were expressed in the adriamycin-resistant KB cells, C-A120, C-A500, and C-A1000, but not in parental KB-3-1 and revertant C-AR cells. The MRP gene was amplified in all the MDR cells that overexpressed MRP mRNA. DNA topoisomerase II levels were markedly decreased in C-A500 and C-A1000 cells but only slightly decreased in C-A120 cells. These results indicate that MRP overexpressed in the resistant cells may be responsible for the reduced accumulation of adriamycin and vincristine and that both the increased expression of MRP and decreased levels of topoisomerase II underlie the drug resistance in C-A120, C-A500, and C-A1000 cell lines.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Electrical analogy of diastolic pressure difference between left atrium and ventricle.

We proposed a mathematical model to describe the early filling process of the left ventricle and applied the model to in vivo experiments. The solution of a second-order differential equation indicated that the pressure difference between the left atrium and ventricle during ventricular filling (PD) could be explained by a transient response, i.e. decremental oscillation, in an LCR circuit. Thereafter, we analysed the sequence of PD during vagal stimulation with two catheter-tip manometers in 12 anaesthetised dogs and evaluated changes in the parameters of the system under various haemodynamic conditions. The values of omega n and zeta were quite stable among beats within an episode of vagal stimulation, between episodes and even among dogs, despite the changes in haemodynamic variables. Pericardiotomy and partial discommunication of the mitral valve with the left ventricular free wall by cutting the mitral chordal tendons decreased omega n and increased zeta, mainly because of the increase in CLV. Occlusion of the coronary vascular beds with large numbers of microspheres increased omega n and decreased zeta, mainly because of the decrease in CLV. Mitral obstruction with an inflated balloon (increase in R) abolished the oscillatory changes and produced an exponential decay sequence of PD. In conclusion, both the logical and experimental approaches indicated that the sequence of PD could be considered as decremental oscillation in the LCR circuit and the parameters omega n and zeta could be good indices of the diastolic property of the left ventricle.

Animals↗
PubMed1994

Human arterial smooth muscle cell strains derived from patients with moyamoya disease: changes in biological characteristics and proliferative response during cellular aging in vitro.

Moyamoya disease is a progressive cerebrovascular occlusive disease that occurs frequently in children. The etiology is unknown. We examined changes in biological characteristics and responsiveness to serum mitogens during the in vitro cellular aging of arterial smooth muscle cell strains derived from patients with moyamoya disease (HMSMC) and compared them with those of cells from age-matched control patients (HCSMC). HMSMC had a normal human diploid chromosome constitution. HMSMC and HCSMC had almost the same in vitro life span and the age-related patterns of biological parameters were essentially the same. However, the doubling time at the early passages was significantly longer in moyamoya SMC than control SMC, although there was no significant difference at the late passages. Furthermore, the poor responsiveness of moyamoya SMC to platelet-derived growth factor was retained throughout the life span in vitro. These results support the hypothesis that functional alterations in vascular cells are involved in the mechanism of development of intimal thickening in moyamoya disease.

Adolescent↗
PubMed1994

In vivo dopamine-D2 and serotonin-5-HT2 receptor binding study of risperidone and haloperidol.

An in vivo receptor binding technique was applied to evaluate the affinities of risperidone and haloperidol for dopamine-D2 receptors (D2) and serotonin-5-HT2 receptors (5-HT2) in rat brain with [3H]YM-09151-2 and [3H]ketanserin as selective ligands. Radioactivities were obtained in the striatum frontal cortex, and cerebellum of the rats treated with the ligands. Time course study of receptor occupancy at 25 to 250 min after single doses of the drugs (1 mg/kg, IP) showed higher 5-HT2 occupancy in the frontal cortex and lower D2 occupancy in the striatum by risperidone than by haloperidol. Dose-response analysis of receptor occupancy revealed risperidone demonstrated higher binding affinity for 5-HT2 than for D2, while the reverse was observed with haloperidol. It appeared that risperidone (1 mg/kg, IP), but not haloperidol (1 mg/kg, IP), demonstrated regional selectivity in D2 occupancy favouring frontal cortex more than the striatum. That risperidone displayed a higher ratio of 5-HT2 to D2 in occupancy than haloperidol is in agreement with the previous findings obtained in vitro.

Animals↗
PubMed1994

Time course of dopamine1,2 and serotonin2 receptor binding of antipsychotics in vivo.

An in vivo receptor binding technique was applied to evaluate the affinities of clozapine (20 mg/kg), RMI-81582 (20 mg/kg), and haloperidol (1 mg/kg) for dopamine D1, D2 and serotonin 5-HT2 receptors in rat brain with [3H]-SCH23390, [3H]-YM-09151-2, and [3H]-ketanserin as selective ligands. The time course study of receptor occupancy at 25 to 250 min after intraperitoneal administration of the drugs showed higher 5-HT2 and lower D2 receptor occupancies of clozapine and RMI-81582 than those of haloperidol both in the striatum and frontal cortex. The 5-HT2/D2 ratios of receptor occupancy for clozapine and RMI-81582 were about 6 to 8 times higher than that for haloperidol. Stable occupancies of D1 receptors were observed only with RMI-81582 and clozapine, the former demonstrating the higher occupancy. These findings are in agreement with the previous findings obtained under in vitro conditions and may account for some part of the properties of atypical antipsychotic drugs.

Animals↗
PubMed1994

Vasoinhibitory effects of NC 1005 and NC 1006, new synthesized antiarrhythmic agents, in isolated rat aorta.

1. NC 1005 and NC 1006 (3 x 10(-6) M-10(-4) M) inhibited the contractions induced by phenylephrine (PE) and KCl in isolated rat aortas with or without endothelium. 2. In a Ca(2+)-free medium containing EGTA and nifedipine, NC 1005 and NC 1006 inhibited PE-response and a subsequent response to Ca2+ in the presence of PE. 3. NC 1005 and NC 1006 also caused relaxations of endothelium-removed aortas precontracted with PE. 4. The relaxations induced by NC 1005 and NC 1006 were potentiated by amiloride, zaprinast and theophylline but not by increasing the external Na+ concentration. 5. Methylene blue and ouabain slightly potentiated NC 1005-relaxation, but not NC 1006-relaxation. 6. Glyburide, apamine and nifedipine had no effect on the relaxations. 7. NC 1005 and NC 1006 potentiated the relaxation induced by nitroglycerin (NG) without affecting isoproterenol-relaxation. 8. In the presence of forskolin, NC 1005 and NC 1006 failed to potentiate NG-relaxation. 9. These results suggest that the vasoinhibitory effects of NC 1005 and NC 1006 may be due to an increase in the level of cAMP.

Aniline Compounds↗
PubMed1994

T cell receptor (beta chain) transgenic mice have selective deficits in gamma delta T cell subpopulations.

TCR-beta (T cell receptor-beta chain) transgenic mice have altered lymphocyte development. TCR-beta transgenic mice are hyporesponsive to alloantigens in vivo and are deficient in gamma delta T cells. In order to begin a study of the relationship between a deficiency of alloreactive gamma delta cells and the defective function of in vivo alloantigen recognition, we analysed the gamma delta T cell development in TCR-beta mice. The presence of the TCR-V beta 8.2 chain transgene is associated with inhibition of gamma chain gene rearrangement. In order to determine how the presence of the TCR-beta transgene affects gamma delta T cell development, gamma delta T cells were studied in the skin, intestine and spleen. TCR-beta mice have dramatically reduced numbers of gamma delta T cells in the spleen and moderately reduced numbers of gamma delta T cells among intestinal intraepithelial lymphocytes. In contrast, these mice have normal numbers of gamma delta dendritic epidermal cells (DEC). These selective deficits could be due to the developmental regulation of transgene transcription during fetal life. We examined transcription of the TCR-beta transgene in the fetal thymus and found that the TCR-beta transgene is first transcribed at high levels on day 16 of fetal life, after DEC have already migrated from the thymus to the epidermis. Furthermore, mRNA from the transgene was detected in DEC, ruling out the formal possibility that DEC bear a gamma delta receptor only because they are incapable of expressing the transgene.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Tissue-specific expression of the gene encoding a mouse RNA binding protein homologous to human HuD antigen.

We have cloned and sequenced cDNAs encoding a mouse RNA-binding protein that is homologous to human HuD antigen. The amino acid sequence deduced from the nucleotide sequence has revealed that the mouse HuD protein is identical to the human counterpart except for two amino-acid substitutions outside the three RNA recognition motifs (RRMs) and a difference in the N-terminus. The mouse HuD gene produces two major brain-specific mRNAs (3.7 kb and 4.4 kb) and a minor testis-specific mRNA (1.3 kb), which is indicative of alternative RNA processing. These results suggest that the mouse HuD homolog is a member of the tissue-specific RNA-binding protein family, possibly involved in RNA metabolism in the nervous system.

Amino Acid Sequence↗
PubMed1994

Selective decrease of eumelanin in hypopigmented epidermis of hypomelanosis of Ito.

A Japanese infant had bilateral hypopigmented macules in a whorled or marble-cakelike configuration on her trunk and extremities. Her irides were bluish gray and her hair was dark brown. She had photophobia and macrocephaly with developmental delay. Analysis of peripheral lymphocytes and dermal fibroblasts disclosed a normal chromosomal pattern. A new finding was that the eumelanin content of the hypopigmented epidermis was decreased. We suggest that at least a portion of patients with this disorder have a defect in eumelanogenesis in hypopigmented skin.

Epidermis↗
PubMed1994

Enterotoxic activity of Klebsiella oxytoca cytotoxin in rabbit intestinal loops.

We examined the enterotoxicity of a Klebsiella oxytoca cytotoxin which is produced by K. oxytoca OK-1, a strain from a patient with antibiotic-associated hemorrhagic colitis. Injection of the cytotoxin into ligated ileal and colonic loops in rabbits caused the accumulation of fluid in the loops. The fluid was bloody in the ileal loops but not in the colonic ones. Histological examination revealed intense mucosal hemorrhage with erosion in the ileum, whereas no microscopic change was noted in the colon. The fluid accumulation was shown to be a dose-dependent response in both ileal and colonic loops. The amounts of the cytotoxin required for maximal fluid accumulation in ileal and colonic loops were 60 and 10 micrograms, respectively. Fluid accumulation was first noticeable in ileal loops 12 h and in colonic ones 5 h after the injection of these doses of the cytotoxin and then proceeded with time. When K. oxytoca OK-1, a cytotoxin-producing strain, was inoculated into the loops at doses of 1 x 10(8) and 5 x 10(9) CFU, similar fluid accumulation was observed. However, inoculation of K. oxytoca ATCC 13182, a non-cytotoxin-producing strain, at the same doses did not cause any change. These results suggest that the cytotoxin-producing strain of K. oxytoca is the causative organism of antibiotic-associated hemorrhagic colitis and that the toxin is the factor responsible for pathogenesis.

Animals↗
PubMed1994

Role of alpha-toxin in Clostridium perfringens infection determined by using recombinants of C. perfringens and Bacillus subtilis.

Clostridium perfringens type A strains which differed in alpha-toxin (phospholipase C [PLC]) productivity were inoculated intraperitoneally or intravenously into mice, and then their 50% mouse lethal doses (LD50) were determined. Strain NCTC 8237 produced ninefold higher PLC activity than strain 13. The mean LD50 for the former was 1 log unit lower than that for the latter. Two isogenic strains were constructed from strain 13: strain 13(pJIR418 alpha) (pJIR418 alpha contains the plc gene), which produced ninefold higher PLC activity than strain 13; and strain 13 PLC-, which showed no PLC productivity at all because of transformation-mediated gene disruption. The mean LD50 for strain 13(pJIR418 alpha) was 1 log unit lower than those for strain 13 PLC- and strain 13. These results indicate that PLC functions as a virulence-determining factor when it is produced in a sufficient amount. Such a difference in LD50 was also observed between Bacillus subtilis with and without the cloned plc gene. Inoculation of B. subtilis PLC+ intravenously into mice caused marked thrombocytopenia and leukocytosis. Mice inoculated with B. subtilis at 2 LD50 died because of circulatory collapse. Histological examination revealed that intravascular coagulation and vascular congestion occurred most prominently in the lungs. These results suggest that PLC plays a key role in the systemic intoxication of clostridial myonecrosis, probably by affecting the functions of platelets and phagocytes.

Animals↗