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Biomedical subjects

Y Saijo

Publications and source records attributed to Y Saijo.

At least 73 records · Page 4Linked to original sources
PubMed1993

The effect of antisense p120 construct on p120 expression and cell proliferation in human breast cancer MCF-7 cells.

Malignant transformation of NIH3T3 cells was observed by transfection with the pSVX vector containing a sense human p120 cDNA construct (pSVX120). Subsequent transfection of these transformed cells with a dexamethasone inducible antisense p120 construct (pMSG021) markedly reduced the expression of human p120 and the growth rate of these transformed cells (Perklaky et al., Cancer Res., (1992) 52, 428-436). In the present study, a human breast cancer cell line (MCF-7) which expresses the p120 protein was transfected by electroporation with a pSVX plasmid-construct containing the antisense p120 cDNA (pSVX021). Clones containing the pSVX021 construct were selected and analyzed for expression of p120 mRNA, protein and growth characteristics. The expression of the p120 protein was inhibited by 44% in the antisense-transfected MCF-7pSVX021 cells; a 56% inhibition of cell-growth and a reduced colony formation in soft agarose were also observed. The growth of MCF-7 cells transfected with the p120 antisense construct was reduced by 93% in nude mice.

Animals↗
PubMed1993

Cellular pharmacology of p120 antisense oligodeoxynucleotide phosphorothioate ISIS 3466.

Previous studies demonstrated that an antisense phosphorothioate oligodeoxynucleotide, ISIS 3466, to the human nucleolar p120 protein, markedly inhibited the growth of human tumor cell lines in vitro and inhibited the growth of the human LOX tumor in vivo in an i.p./i.p. model, in the presence of DOTMA (Perlaky et al., Anti-Cancer Drug Design 8:3-14, 1993). In vitro, DOTMA enhanced the effect of the antisense oligodeoxynucleotide was associated with the LOX cells after 4 hr treatment than in the absence of DOTMA. A 100-fold higher concentration of the oligodeoxynucleotide was required to introduce the same amount of oligodeoxynucleotide into the cells in the absence of DOTMA than in the presence of DOTMA. Kinetic analysis showed that the cell-associated oligodeoxynucleotide accumulated rapidly and reached a plateau after 1 hr incubation. When these cells were placed in a complete medium without the oligodeoxynucleotide, there was a 50% decrease in the oligodeoxynucleotide after 21 hr. A 35% reduction of p120 mRNA and a 50% reduction of p120 protein was found after ISIS 3466 treatment. Further study is needed to explore the tumor-inhibitory mechanisms of the effects of antisense oligodeoxynucleotide ISIS 3466.

Base Sequence↗
PubMed1993

Growth inhibition of human tumor cell lines by antisense oligonucleotides designed to inhibit p120 expression.

The human nucleolar antigen p120 was detected with an anti-p120 monoclonal antibody (MAbp120) in most human malignant tumors (Freeman et al., Cancer Research, 48, 1244-1251, 1988). Stable transfection of the sense p120 cDNA caused malignant transformation of NIH/3T3 cells in vitro, and the antisense p120 constructs markedly delayed the growth of these transformed cells (Perlaky et al., Cancer Research, 52, 428-436, 1992). Several p120 antisense phosphorothioate oligonucleotides designed to hybridize with different regions of the p120 sequence were screened on human tumor cell lines in vitro. Marked growth inhibition of HeLa, LOX and HRCC cell lines was found, particularly with antisense p120 oligonucleotide ISIS 3466 in combination with N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA); oligonucleotide ISIS 3466 is complementary to a non-translated region at the 3' end of the molecule. Preliminary in vivo studies on human LOX ascites tumor in nude mice showed marked inhibitory effects on tumor growth by the antisense oligonucleotide ISIS 3466 in the presence of DOTMA when treated on alternate days.

Animals↗
PubMed1992

A region of antisense RNA from human p120 cDNA with high homology to mouse p120 cDNA inhibits NIH 3T3 proliferation.

The human nucleolar p120 protein is a proliferation-associated antigen which is expressed in G1 and peaks during the early S phase of the cell cycle. Overexpression of the human p120 protein caused the transformation of NIH 3T3 cells and expression of an antisense p120 construct inhibited the growth of NIH 3T3 cells (Perlaky et al., Cancer Res., 52:428-436, 1992). The middle region of the antisense p120 RNA was found to be almost as inhibitory as the full length antisense construct but the 5' and 3' antisense portions did not affect NIH 3T3 cell proliferation. After the mouse p120 complementary DNA was cloned and sequenced, comparison with the human p120 complementary DNA showed a striking conservation of 85% of the nucleotide sequence and 96% of the amino acid sequence. The two ends of the p120 molecule had less homology in their nucleotide and amino acid sequences. Based on this homology, the observed inhibitory effects of the middle portion of antisense human p120 RNA may be related to suppression of mouse p120 expression by RNA:RNA duplex formation. The high evolutionary conservation of the middle region suggests it has a critical role for the function of this protein.

3T3 Cells↗
PubMed1992

Changes in serum erythropoietin levels during chemotherapy for lung cancer.

Serial serum erythropoietin (EPO) levels were measured in 12 adult lung cancer patients during cancer chemotherapy. In major cases, EPO levels increased significantly after chemotherapy while the hemoglobin (Hb) remained at initial levels. EPO fell gradually or rapidly to initial levels after a peak, although the patients were anemic. The increase of EPO levels was linearly related to the decrease in Hb (y = 17.48x + 1.003). The mechanism of the rapid increase of EPO is not simply explained by anemia, but might be related to new synthesis, corresponding to depressed bone marrow.

Adult↗
PubMed1992

Protein kinase C activity in human leukemia cell lines with reference to sensitivity to antineoplastic agents.

Protein kinase C (PKC) regulates many cellular processes. In view of its possible relevance to the drug resistance, the levels of PKC activity were assessed in human leukemia cell lines with reference to the sensitivity to antineoplastic agents. K562/ADM exhibited approximately 2-fold higher levels of PKC activity as compared with the parental K562. After a 1-hr preincubation with Adriamycin (ADM) (0.5, 1, 10 microM), PKC activity in K562 tended to increase dose-dependently, while no substantial alteration was found in K562/ADM. Cisplatin (CDDP) or etoposide was of no effect. The activity in THP-1/E was slightly lower than THP-1, and the basal level stayed unchanged with any one of the above drugs. These results suggest that in K562 increase in PKC activity with ADM may play a role in the process of acquisition of resistance.

Antineoplastic Agents↗
PubMed1991

Increased levels of mitochondrial DNA in an etoposide-resistant human monocytic leukaemia cell line (THP-1/E).

Electron microscopic observations of THP-1/E (an etoposide-resistant human monocytic leukaemia cell line) showed a remarkable change of mitochondrial structure. Mitochondria were swollen and cristae were relatively intact. There was no difference in the activity of cytochrome oxidase, an enzyme which contains three subunits coded by mitochondrial DNA (mtDNA) between THP-1/E and THP-1 (the parent cell of THP-1/E). No measurable quantitative change of mitochondrial RNA was observed, but the level of mtDNA in THP-1/E was increased by a factor of about 4 compared with that of mtDNA in THP-1. These results suggest that, on acquisition of resistance to etoposide, some factors affect mitochondria, change its morphology and amplify its DNA.

Blotting, Northern↗
PubMed1991

The ultrasonic properties of gastric cancer tissues obtained with a scanning acoustic microscope system.

A newly developed scanning acoustic microscope (SAM) system operating in the frequency range of 100-200 MHz has been employed to measure the attenuation and the sound speed of formalin-fixed specimens of five different types of gastric cancer. Signet-ring cell carcinoma specimens exhibit attenuation constant and sound speed values significantly lower than other types of gastric cancer tissues. Tubular adenocarcinoma specimens exhibit a trend toward higher attenuation and sound speed values as the cell type became differentiated. Our measurements and observations suggest that the ultrasonic properties are influenced by cellular arrangement, intercellular junction and intracellular chemical components.

Adenocarcinoma↗
PubMed1991

[A case of giant cell myocarditis associated with a progressive disturbance in the conduction system].

A 73 year old male patient with a history of pulmonary tuberculosis was admitted to our department because of dyspnea and abdominal pain. The chest X-ray film on admission showed bilateral lung congestion. The ECG showed atrial fibrillation, left axis deviation and incomplete right bundle branch block. Five days after admission, the ECG changed into sinus rhythm and complete right bundle branch block. Eight days after admission, the patient complained of chest pain and the ECG showed ST elevation in II, III, aVF, reciprocal ST depression in V, and complete A-V block with junctional rhythm. Emergency coronary angiography revealed no significant stenosis. Echocardiography showed reduced contraction of the inferior wall and diffuse granular echoes in the myocardium. Light microscopic study revealed fibrosis, infiltration of eosinophils and histiocytes, degenerated myocardium and multinucleated giant cells. Some of the giant cells were morphologically similar to myocardium, so the myocardium might be a place of immunological reaction.

Aged↗
PubMed1989

Distribution and metabolism of norepinephrine, cyclic AMP and cyclic GMP in the atrioventricular conducting tissue of the bovine heart.

The distribution of norepinephrine (NE), cyclic AMP (cAMP) and cyclic GMP (cGMP) and the activities of related enzymes in the atrioventricular (A-V) conducting tissue of the bovine heart were examined. The concentration of NE in the atrium was about twice that in the ventricle. In the A-V conducting tissue, the concentration of NE was highest in the atrioventricular node (AVN) and lowest in the false tendon (FT), with intermediate levels in the bundle of His (HIS) and the right and left bundle branches (RLBB). The activity of monoamine oxidase (MAO) in the atrium was about 2.2 times that in the ventricle. In the A-V conducting tissue, the activity of MAO was highest in the HIS and lowest in the FT. The activity of catechol-o-methyltransferase (COMT) in the atrium and ventricle was similar, and that in the HIS was slightly, but not significantly, higher than that in other regions of the A-V conducting tissue. The concentration of cAMP in the ventricle was about twice that in the atrium. In the A-V conducting tissue, the concentration of cAMP was higher in the AVN and FT than in the HIS and RLBB. The distribution of adenylate cyclase (AC) was similar to that of NE. The phosphodiesterase (PDE) activity in the atrium and ventricle was similar. No significant difference was found in the level of PDE activity in different regions of the A-V conducting tissue. The concentration of cGMP was slightly, but not significantly, higher in the A-V conducting tissue than in the atrium or ventricle. In the A-V conducting tissue, the concentration of cGMP was highest in the FT and the concentrations in the HIS, RLBB and AVN were similar. These findings suggest that in the A-V conduction tissue, the regions that have the higher spontaneous pacemaker rates have higher NE content and AC activity, that is sensitivity to NE. Furthermore, the sensitivity for muscarinic cholinergic stimulation is higher in the conducting tissue (especially in the FT) than in the atrium and ventricle.

Adenylyl Cyclases↗
PubMed1989

Establishment of an etoposide (VP-16)-resistant subline of THP-1 human monocytic leukemia cell line.

A VP-16-resistant subline was established from THP-1 human monocytic leukemia cells by subculturing in stepwise increasing concentrations of the drug. The resistant cells (THP-1/E) were capable of sustaining continuous growth in 1.0 microgram/ml VP-16. The 50% inhibition dose (IC50) was 1.4 micrograms/ml or a 35-fold of the parent cells. A more than 18-fold IC50 was also obtained with teniposide (VM-26). However, no substantial cross-resistance was observed with 5 other antineoplastic drugs, IC50 values being limited below several times of THP-1.

Cell Division↗
PubMed1989

Characterization of resistance to VP-16 in human leukemic cell line.

Resistance mechanism was studied in the VP-16-resistant human leukemic cell line (THP-1/E) which was developed by continuous drug exposure. The drug uptake and efflux studies revealed no decrease in net cellular drug accumulation. VP-16-induced DNA single- and double-strand breaks in the whole THP-1/E cells decreased significantly compared to the sensitive counterpart as assessed by alkaline elution methods. Decrease in DNA SSBs was also observable in the isolated nuclei from the THP-1/E cells. The resistance to VP-16 in THP-1/E appeared to be independent of altered membrane permeability, and more likely to be associated with decreased VP-16-mediated DNA cleavage.

Cell Line↗
PubMed1989

Myocardial disorders caused by magnesium deficiency in diabetic KK mice.

Studies were made on the diabetic state and the pathogenesis of myocardial disorders in KK mice with the following results: (1) KK mice showed glucose intolerance, hyperinsulinemia and hyperlipidemia; (2) their electrocardiograms (ECGs) showed a marked left-axis deviation of the QRS vector; (3) they showed epicardial calcification and myocardial disorders; (4) the Ca content of their myocardiums was much higher, and the Mg contents in the erythrocytes and myocardiums were much lower than those of control mice; (5) the addition of Mg to the drinking water of KK mice normalized these changes, and suppressed their myocardial disorders, but did not normalize their ECG changes. These results suggested that Mg deficiency plays an important role in the development of myocardial disorders in KK mice.

Animals↗
PubMed1986

[An autopsy case of lung cancer in a young adult dwarf].

A 31-year-old man with peripheral squamous cell carcinoma is reported. By nature he was very small. On admission he was 140 cm tall, weighed 28 kg, and was complaining of chest pain of five years duration. A giant tumor in the right lung was found to be moderately differentiated squamous cell carcinoma. He also had congenital anomalies, such as crossed ectopic kidney with fusion, café-au-lait spots, inguinal hernia, simian line, etc. He had never been exposed to cancer-causing agents. In conclusion, genetic factors related to intrauterine growth retardation might have been linked to his oncodevelopmental mechanisms.

Adult↗