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Biomedical subjects

Y Kano

Publications and source records attributed to Y Kano.

At least 127 records · Page 7Linked to original sources
PubMed1994

Muscular composition of the gastric groove in the golden hamster.

The golden hamster possesses a forestomach and a glandular stomach. The gastric groove connects the cardia to the glandular stomach and is situated on the lesser curvature of the stomach. The constitution of the muscle fibers in the gastric groove was investigated. The gastric groove consisted of two lips and a groove floor. The muscle coat of the lips was composed of a mixture of smooth and striated muscle fibers. The smooth muscle fibers were components of the cardiac muscle loop. The striated muscle fibers were extensions from the esophageal inner circular muscle layer, and invaded about half the length of the lips. The muscle coat of the groove floor consisted of an inner circular muscle layer made up of smooth muscle fibers, and the outer longitudinal muscle layer of the striated muscle fibers extended from the esophageal outer longitudinal muscle layer. The present study revealed that the muscle coat of the gastric groove in the golden hamster was composed of smooth and striated muscle fibers, and that these striated muscle fibers were extensions of the esophageal muscle coat.

Animals↗
PubMed1994

Autoregulation of transcription of the hupA gene in Escherichia coli: evidence for steric hindrance of the functional promoter domains induced by HU.

The molecular mechanism of autoregulation of expression of the hupA gene in Escherichia coli was examined. The promoter of the gene contains a palindromic sequence with the potential to form a cruciform DNA structure in which the -35 sequence lies at the base of the stem and the -10 sequence forms a single-stranded loop. An artificial promoter lacking the palindrome, which was constructed by replacing a 10 nucleotide repeat for the predicted cruciform arm by a sequence in the opposite orientation, was not subject to HU-repression. DNA relaxation induced by deleting HU proteins and/or inhibiting DNA gyrase in cells results in increased expression from the hupA promoter. We propose that initiation of transcription of the hupA gene is negatively regulated by steric hindrance of the functional promoter domains for formation of the cruciform configuration, which is facilitated at least in part by negative supercoiling of the hupA promoter DNA region. The promoter region of the hupB gene also contains a palindromic sequence that can assume a cruciform configuration. Negative regulation of this gene by HU proteins may occur by a mechanism similar to that operating for the hupA gene.

Bacterial Proteins↗
PubMed1994

Increased retention of small chromosomes in a novel yeast mutant.

MSC201 and MSC202 are novel yeast mutant strains in which a 10-kb linear yeast artificial chromosome (YAC) was stably maintained in unselective medium during mitotic cell division. After culturing for 35 cycles of cell division, about 50% of MSC cells retain YAC3 DNA, compared to 0.001% of the wild-type AB1380 strain. Southern blot hybridization analysis with pBR322 DNA as the probe showed that in the MSC transformants, YAC DNA remained in a linear form free of cellular chromosomal DNA. The msc201 mutation was shown to be recessive by the rapid loss of the YAC in a diploid strain made by mating with AB1375, which has a genetic background similar to that of the MSC strain. Linear YAC DNA with a centromere was stabilized in MSC201 better than a linear construct lacking a centromere sequence.

Chromosomes, Artificial, Yeast↗
PubMed1994

Construction of a gyrA-gyrB-carrying plasmid overproducing functional DNA gyrase.

A plasmid carrying both gyrA and gyrB genes (pTS7) and a plasmid without the gyr gene (pTS4) were constructed. Introduction of pTS7 into the YK1100 (wild-type) cells resulted in an increase in the level of gyrA and gyrB mRNA by 5- to 6-fold over the level of the control transformant with pTS4. In the transformant cells carrying pTS7, the reporter plasmid pGP241, which is compatible with pTS plasmids, was significantly more highly negatively supercoiled than in the transformant with pTS4. The activity of DNA gyrase to supercoil the relaxed pGP241 DNA was 4-8 times higher with the S-30 extract from the transformant carrying pTS7 than with the extract from the transformant with pTS4.

DNA↗
PubMed1994

Effects of the acetylene compound from Atractylodes rhizome on experimental gastric ulcers induced by active oxygen species.

This study was conducted to determine the beneficial effects of treating digestive disorders of (6E,12E)-tetradecadiene-8,10-diyne-1,3-diol diacetate (TDEYA) detected in the plasma in hydrolyzed form: (6E,12E)-tetradecadiene-8,10-diyne-1,3-diol (TDEY), following the oral administration of a decoction of Atractylodes rhizome to rats. Assessment was also made of the efficacy of TDEYA in experimental gastric disorder models. Oral administration of TDEYA at doses of 300 to 500 mg/kg suppressed the formation of gastric lesions induced by indometacin in a dose-dependent manner. TDEYA at a dose of 200 mg/kg suppressed gastric lesions induced by an ischemia-reperfusion injury model. TDEYA at doses of 100 to 300 mg/kg did not show suppressive effects on water immersion stress-induced gastric lesions. TDEYA showed no active oxygen species scavenging action, nor did it have any effect on superoxide dismutase activity in the stomach tissue. TDEYA at doses of 200 to 500 mg/kg significantly suppressed xanthine oxidase (XO) activity in the stomach tissue following its oral administration. The suppressive effects of TDEYA on lesion formation induced by indometacin and ischemia-reperfusion injury models would thus appear to be due in part to the inhibition of XO activity in the stomach tissue.

Acetylene↗
PubMed1994

Urinary and biliary metabolites of daidzin and daidzein in rats.

Examination was made of the urinary and biliary excretion of metabolites of daidzin and daidzein, the major components of roots of Pueraria lobata Ohwi (Leguminosae) in rats. The urine of rats administered daidzin orally contained four major metabolites, daidzein 7,4'-di-O-sulfate (M-1), daidzein 7-O-beta-D-glucuronide (M-2), daidzein 4'-O-sulfate (M-3), daidzein (M-4), as determined from spectroscopic and chemical data. The urine of rats treated with daidzein contained M-2--M-4 in the above metabolites. Total cumulative amounts of the four metabolites excreted in the urine at 48 h following the oral administration of daidzin and daidzein were approximately 4.8% and 4.6% of the doses administered, respectively. The bile of rats administered daidzin orally contained M-1--M-4. Daidzein 7-O-beta-D-glucuronide 4'-O-sulfate (M-5), a major biliary metabolite, was identified by the high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectra. At least daidzin appeared to be hydrolyzed to aglycone after absorption in the body, and as a part of metabolites, M-1--M-4 having free hydroxyl, glucuronided or sulfated hydroxyls at the C-7 position, may then be excreted in the urine and bile.

Administration, Oral↗
PubMed1994

Coexpression of different cytokeratins, vimentin and desmin in the rete testis and epididymis in the dog.

The expression patterns of low and high molecular weight cytokeratins (LCK and HCK) vimentin and desmin were investigated by immunocytochemistry in the rete testis and epididymis in the dog. The epithelium of the rete testis displayed coexpression of LCK, vimentin and desmin. The epithelium of the efferent ductules was composed of ciliated and nonciliated cells; the ciliated cells expressed LCK strongly. The epithelium of the epididymal duct was composed of principal, apical and basal cells. Principal cells in the duct of the head of the epididymis displayed LCK and vimentin, with a predominance of LCK in the apical cytoplasmic regions and vimentin in the basal portions of the cells. Expression of vimentin in the principal cells decreased towards the body of the epididymis and disappeared in the tail region, where LCK remained unchanged. Apical cells of the epididymal duct expressed LCK. Basal cells in the duct of the head and body of the epididymis showed LCK and those of the duct of the body of the epididymis also HCK expression.

Animals↗
PubMed1994

[Aging and immortalization of human cells].

In vitro models of malignant transformation of human cells may provide considerable insight into the mechanisms of multistep carcinogenesis. It is well established that normal human cells must be immortalized before they are malignantly transformed, but normal human cells are extremely refractory to immortalization, making malignant transformation very difficult. Thus immortalization is a rate-limiting step in the malignant transformation of human cells. In order to immortalize normal human cells with a chemical carcinogen, 4-nitroquinoline 1-oxide, or with 60Co gamma rays, the cells had to be repeatedly treated with these agents. This indicates that the immortalization process involves multiple mutational events and is itself a multi-step process. Then we found that there were mutations in p53 in all our immortalized cell lines. This encouraged us to attempt to immortalize human cells with the mutant p53. We introduced the mutant p53 (codon 273Arg-His) into normal human fibroblasts to learn whether the cells could be immortalized. The p53 extended the life-span of the cells but could not immortalize them. However, when we treated the p53-introduced cells with 4NQO, the cells were immortalized. The 4NQO treatment alone did not make the cells immortal. These results indicate that the p53 gene play a role in immortalization of human cells rather than in their malignant transformation.

4-Nitroquinoline-1-oxide↗
PubMed1994

[Effects of SN-38 in combination with other anticancer agents against Dauji cells].

To investigate the effects of CPT-11 in combination with other anticancer agents, a human Burkitt's lymphoma cell line, Dauji, was incubated for 3 days in the presence of SN-38 (active substance of CPT-11) and the combined drug and cell growth inhibition was determined by MTT assay. The effects of the drug combinations at ID50 were then analyzed by isobologram (Steel and Peckham). A supra-additive (synergistic) effect was observed for SN-38 in combination with carboplatin, cisplatin, cytosine arabinoside, and mitomycin C. An additive effect was observed for its combination with bleomycin, etoposide, 5-fluorouracil, and mitoxantrone. Additive and sub-additive (antagonistic) effects were observed in combination with doxorubicin. A Sub-additive effect was observed in combination with methotrexate and vincristine.

Antineoplastic Agents, Phytogenic↗
PubMed1994

[Dose effects on vital parameters of guinea pig by continuous administration of cisplatin].

A wide used anti-neoplasmic agent, cisplatin (CDDP), injures normal organs dose-dependently by its toxicity. The mechanisms of organ injuries have been studied to prevent and rescue patient conditions. We analyzed the relation between CDDP doses and onset of organ injuries to clarify the mechanism of CDDP toxicity. The onset doses to cause organ injuries were calculated using weekly collected vital parameters of 18 male guinea pigs which were injected CDDP (2 mg/kg/day, 5 times/week) intraperitonealy until the death of animals. Correlations between the values of vital parameters and CDDP doses and applicative survival curve method were used to estimate the onset doses. Abnormal changes in iron metabolism and auditory organ were first noted at 10.2 mg/body and 10.8 mg/body of CDDP, respectively. The change in the salivary glands were noted at 15 mg/body. Renal injury started at 19.5 mg/body, and damages to the bone marrow started between 19.7 mg/body to 33.6 mg/body of CDDP. The minimal dose of liver dysfunction was 21.3 mg/body. It is concluded from these results that 1) the onset of organ injury depends on the dose of CDDP, and 2) the order of such injuries was iron metabolism, auditory organ, the salivary glands, kidney, the bone marrow, and the liver in guinea pigs, 3) Other organ injuries might be detected to clarify hearing levels during chemotherapy because those were noted following auditory damage except iron metabolism.

Animals↗
PubMed1993

Propagation of phage Mu in IHF-deficient Escherichia coli in the absence of the H-NS histone-like protein.

Integration host factor (IHF) is known to be required for the expression of early genes and formation of the transpososome of mutator phage Mu. Prophage Mucts62 was stably maintained at 30 degrees C and proliferated effectively after thermal induction at 42 degrees C in an Escherichia coli mutant defective in the histone-like H-NS and IHF proteins. No IHF activity was detected in cells lacking H-NS and IHF; cells could not be transformed with plasmid pCL1920, which is based on the pSC101 replicon whose replication requires IHF. No difference in the superhelical densities of the reporter plasmid was detected in the H-NS, IHF null mutant and parental cells. From these results it is concluded that IHF is not essential for Mu development. These results also suggest that H-NS may function as a silencer for Pe operon expression and that IHF overcomes the inhibitory effect of H-NS.

Bacterial Outer Membrane Proteins↗
PubMed1993

Sex differences in the anteroventral periventricular nucleus of the preoptic area and in the related effects of androgen in prenatal rats.

The density of cells in the anteroventral periventricular nucleus (AVPv) of the preoptic area of female rats was greater than that of males on day 21 of gestation. It appears that this difference between the sexes is caused by the action of androgen since the density of cells in the AVPv of female fetuses fell to the density in males when the mother received injections of testosterone propionate (TP) on days 14-18 of gestation. Pycnotic cells were more frequently found in oil-treated control males and TP-treated female fetuses than in control female fetuses. This result suggests that the prenatal injections of TP enhanced the rate of degeneration of the cells in the AVPv.

Animals↗
PubMed1993

Immortalization of epithelial-like cells from human liver tissue with SV40 T-antigen gene.

The cells derived from the human embryo liver tissue were transfected with a plasmid pSV3neo containing both the large and small T-antigen gene of the early region of simian virus 40 (SV40), and two cell strains, OUMS-21 and -22, were obtained. OUMS-22 cells, to date, have reached over 100 population doublings through a culture crisis and are considered to have become an immortal cell line. However, OUMS-21 cells failed to become an immortal cell line. Both OUMS-21 and -22 cells were SV40 T-antigen-positive, epithelial-like, and immunoreactive against an anti-keratin 18 monoclonal antibody but against neither an anti-vimentin nor an anti-von Willebrandt factor VIII monoclonal antibody. The staining pattern of cytokeratin in these cells was similar to that in the differentiated human hepatoblastoma and hepatocellular carcinoma cell lines but not to that in the human cholangiocellular carcinoma cell lines. OUMS-21 and -22 cells expressed neither alpha-fetoprotein nor albumin mRNAs. These cells showed no tyrosine aminotransferase activity. However, both OUMS-21 and -22 cells were sensitive to cytotoxicity of aflatoxin B1, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole, and benzo[a]pyrene, whereas human embryo lung fibroblasts were insensitive to the cytotoxicity of these carcinogens. These findings suggest that OUMS-21 and -22 cells may arise from undifferentiated liver stem cells or from hepatocytes that lost their ability to express the liver-specific functions prior to immortalization. Both OUMS-21 and -22 cells expressed glutathione S-transferase pi (GST-pi) mRNA. The expression of GST-pi mRNA highly increased in OUMS-22 cells with their immortalization. Karyotypic analysis showed that numerical and structural aberrations of the chromosomes were profound, but neither specific events nor marker chromosomes were found in OUMS-21 and -22 cells. Both OUMS-21 and -22 cells could grow in soft agar, but they were not tumorigenic when transplanted into nude mice.

Aflatoxin B1↗
PubMed1993

Comparative immunohistolocalization of carbonic anhydrase isozymes I, II and III in the equine and bovine digestive tract.

Immunohistochemical localizations of carbonic anhydrase isozymes (CA-I, CA-II and CA-III) in equine and bovine digestive tracts were studied. In the horse, epithelial cells in both the oesophagus and non-glandular part of the stomach lacked all three isozymes. In contrast, surface epithelial and parietal cells in the glandular region of the stomach showed reactivity for CA-II. In the small intestine, absorptive columnar cells covering the villi in the duodenum were positive for CA-II. The epithelium of the jejunum and ileum lacked all three isozymes. In the large intestine, CA-II was detected in the columnar cells in the upper part of the crypt. In cattle, epithelial cells of the oesophagus showed reactions for CA-I and CA-III but not for CA-II. Although the absorptive epithelial cells of the small intestine lacked CA-I, CA-II and CA-III, those of the upper part of large intestine crypts were heavily stained for all three isozymes.

Animals↗
PubMed1993

Cellular fibronectin on intraocular lenses explanted from patients.

We investigated the origin of fibronectin (FN) on five posterior and four anterior chamber explanted intraocular lenses (IOLs) using immunohistochemical methods. Cellular deposits (assumed to be macrophages) and fibrous or membrane-like proteinaceous deposits on the IOLs showed immunoreactivity to an antibody against cellular FN. These proteinaceous deposits were believed to be products of the cells that adhered to the IOLs.

Aged↗
PubMed1993

Alteration in the retinoblastoma gene associated with immortalization of human fibroblasts treated with 60Co gamma rays.

Genetic analysis was carried out in human fibroblasts (KMST-6) immortalized by treatment with 60Co gamma rays in order to determine if any genetic change was involved in the immortal transformation of human cells. Analysis by restriction fragment length polymorphism revealed an alteration in chromosome 13q12-14, in which the retinoblastoma (RB) gene locus (13q14) is located. Then the RB gene itself was examined. Structural abnormalities in the RB gene were detected by Southern blot analysis. Furthermore, abnormal RB protein (pRB) was expressed in immortalized KMST-6 cells, as shown by in vitro phosphorylation, whereas normal KMS-6 cells expressed the intact pRB. These findings indicated that inactivation of the RB gene is one of the key events of the immortalization of human cells.

Cell Transformation, Neoplastic↗
PubMed1993

Electrophysiological abnormalities before and after surgery for atrial septal defect.

The authors evaluated the electrophysiological parameters, atrial-His interval, His-ventricular interval, Wenckebach cycle length, corrected sinus node recovery time (CSNRT), and sinoatrial conduction time (SACT) before and after operation in 28 children with atrial septal defect (ASD). Before operation, electrophysiological abnormalities were detected in 20 (79%) of the 28 patients. Preoperative comparison of the mean value in each parameter between the two age groups showed higher values in all parameters in the older group. In 17 patients who underwent operation, atrial-His interval, Wenckebach cycle length, CSNRT, and atrial effective refractory period (AERP) significantly decreased after operation; preoperatively abnormal Wenckebach cycle length, CSNRT, and AERP values were normalized in many of them. Thus, electrophysiological abnormalities were already present before operation in the ASD children and were severer in the older children, but were improved to some degree following operation.

Adolescent↗