Search PubMed⌕ Search

Biomedical subjects

S Kaneda

Publications and source records attributed to S Kaneda.

At least 37 records · Page 2Linked to original sources
PubMed1999

Treating neonatal rats with 6-hydroxydopamine induced an increase in voluntary alcohol consumption.

Brain dopamine (DA) and serotonin (5-HT) neurotransmission have been implicated in the mediation of alcohol-seeking behavior. We examined the effects of treatment of neonatal rats (3 days after birth) with the neurotoxin 6-hydroxydopamine (6-OHDA; 100 microg/10 microl, intracerebroventricularly) on the relationship between the levels of neurotransmitters and alcohol drinking behavior at the age of 14 weeks. 6-OHDA treatment reduced the levels of DA and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the nucleus accumbens (ACC), frontal cortex, striatum (STR), tegmentum/substantia nigra, and dorsal raphe nucleus. 5-HT levels in the ACC and STR were increased in the 6-OHDA-treated rats. 6-OHDA-treated rats showed increased alcohol consumption. There was a significant change in the ratio of [5-hydroxyindoleacetic acid]/[5-HT] in the ACC and STR of the treated rats, but no difference in the ratio of [DOPAC]/[DA] between the sham-operated controls and treated rats. 6-OHDA-treated rats had dopaminergic dysfunction in the five brain regions related to the reward system, in part, and a decrease in 5-HT turnover, including the accumulation of 5-HT in the ACC and STR. Furthermore, basal extracellular releases of DA and 5-HT of the ACC were significantly lower in the 6-OHDA-treated rats, compared with the controls. It was suggested that alcohol seeking behavior is associated with the alterations of dopaminergic neurons and the release of 5-HT in the mesocorticolimbic system.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1999

Synthesis and pharmacological activity of pyrazolopyrrolopyrimidine derivatives having vasorelaxing activity.

A new series of 5-substituted and 5-nonsubstituted pyrazolopyrrolopyrimidine derivatives were synthesized, and their vasorelaxing and hypotensive activities were evaluated. The syntheses were efficiently accomplished through the use of three key intermediates (7, 16, and 24), as shown in Schemes I-III. The desired pharmacological activities were confirmed on the basis of vasorelaxing activity in rat aorta (in vitro) and hypotensive activity in rats (in vivo). Specifically, compound 25 exhibited the strongest activity and appears to be a promising clinical lead for the development of a new antihypertensive agent.

Animals↗
PubMed1998

Transient hypothermia induces micronuclei in mice.

We investigated the effect of hypothermia on micronucleus induction in mouse bone marrow cells. To induce hypothermia, we administered chlorpromazine, which was negative in an in vitro chromosome aberration test, at 3.13, 6.25, 12.5, 25, 50, and 100 mg/kg intraperitoneally. Doses of 12.5-100 mg/kg decreased rectal temperature transiently to less than 33 degrees C. The temperature depression following 25-100 mg/kg lasted for 11 h before returning to normal 24 h later except for the 100 mg/kg treatment group. Doses of 25-100 mg/kg produced a statistically significant (p < 0.01) increase in micronucleated polychromatic erythrocyte frequencies 48 h after dosing. When mice that were administered chlorpromazine at 25, 50, and 100 mg/kg were exposed to an environmental temperature of 30 degrees C for 46 h to keep their body temperature within normal range, the frequency of micronucleated erythrocytes did not increase. In addition, relatively large micronuclei (diameter of micronucleus > or = 1/4 diameter of cytoplasm) accounted for 53-58% of the induced micronuclei. The results suggest that the transient hypothermia of less than 33 degrees C for 11 h induced micronuclei in bone marrow cells, and one possible mechanism was disturbance of the mitotic apparatus.

Animals↗
PubMed1998

Effects of pH and osmolality on phlebitic potential of infusion solutions for peripheral parenteral nutrition.

In this study, we investigated the phlebitic potentials of several infusion solutions for peripheral parenteral nutrition to clarify the effects of pH and osmolality on the development of infusion phlebitis. A 10% glucose solution with electrolytes (GE, pH 4.93, 727 mOsm/kg), a 10% amino acid solution (AA, pH 6.95, 929 mOsm/kg), or a 5:2 admixture of GE and AA (GEAA, pH 6.46, 779 mOsm/kg) was infused into the rabbit ear vein for 6 hr at 10 mL/kg/hr, and the infused veins were examined histopathologically. Both GE and AA caused phlebitic changes, such as loss of venous endothelial cells, inflammatory cell infiltration, and perivascular edema. However, their admixture, GEAA, caused scant phlebitic changes. These results were as follows: 1) rabbit peripheral veins could tolerate the pH (6.46) and the osmolality (779 mOsm/kg) of GEAA under the conditions of this study; 2) GE caused phlebitis due to its acidity (pH 4.93); 3) AA caused phlebitis due to its hyperosmolality (929 mOsm/kg); and 4) mixing GE and AA eliminated the factors causing phlebitis in each solution. The admixture of GE and another 10% amino acid solution (AB, pH 6.04) at the ratio of 5:2 (GEAB, pH 5.76, 758 mOsm/kg) caused phlebitic changes. Since its osmolality was lower than that of GEAA, it was considered that GEAB caused phlebitic changes due to its acidity (pH 5.76), which was attributed to the acidic amino acid solution used as a component.

Amino Acids↗
PubMed1997

Cloning and expression of cDNA encoding the human 150 kDa oxygen-regulated protein, ORP150.

We have cloned a cDNA encoding the human 150 kDa oxygen-regulated protein (ORP150) from hypoxia-treated astrocytoma U373 cDNA library. The deduced amino acid sequence of 999 residues contains a signal peptide and an ER retention-like signal at the N- and C-termini, respectively. It has a striking sequence similarity (91% identity) with Chinese hamster 170 kDa glucose-regulated protein (GRP170). The N-terminal half of ORP150 exhibits significant similarity to the ATPase domain of HSP70 family proteins with well-conserved ATP binding motifs. Northern blot analysis revealed that induction of ORP150 in U373 cells was not limited to hypoxia but also observed by 2-deoxyglucose or tunicamycin treatment. Furthermore, tissue specificity of expression of ORP150 was quite similar to that of GRP78. These findings suggest that ORP150 participates in quality control of proteins in the ER in response to diverse environmental stresses.

Adult↗
PubMed1997

Isolation and characterization of autolysin-defective mutants of Staphylococcus aureus that form cell packets.

Staphylococcus aureus produces multiple bacteriolytic enzymes (autolysins) and grows usually as a mixture of single cells, pairs, short chains, and irregular clusters. Autolysin-defective mutants that form cubic cell packets (Pa4A and PaH13) or grape-like clusters (Cu9S and CuD10) were isolated from S. aureus FDA 209P after mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. The Pa4A mutant grown in nutrient broth formed cell packets consisting of 8-64 cells that appeared regularly arranged in three dimensions. Thin-section electron micrographs revealed that the packet cells were encased in an orderly manner within a thick peripheral wall and that their septa failed to split. Zymographic analysis of enzyme extracts from mutant Pa4A showed that it lacked the 33-kDa autolytic enzyme band present in the parent strain. Another mutant, Cu9S, formed grape-like clusters and showed a single autolytic enzyme band (33-kDa). The possibility that the 33-kDa autolytic enzyme is involved in splitting of the septum prior to cell separation inS. aureus is discussed.

Methylnitronitrosoguanidine↗
PubMed1997

Effect of environmental temperature on muscle protein turnover and heat production in tube-fed broiler chickens.

The present experiments were undertaken to investigate the effects of environmental temperatures on growth, abdominal fat content, rate of muscle protein turnover, and heat production in tube-fed intact male broiler chickens. Plasma concentrations of thyroxine (T4), triiodothyronine (T3), and corticosterone (CTC) were also examined. Chicks (15 d old) were kept at different environmental temperatures (16, 19, 22, 25, 28, 31, and 34 degrees) and given the experimental diet (200 g crude protein/ kg, 13.57 MJ/kg metabolizable energy) by tube three times daily throughout the 12 d experimental period. In the hot conditions, except for 34 degrees, body-weight gain was significantly higher than in the cold conditions. Thus, food conversion ratios (food:gain ratios) were lower when the birds were exposed to the hot conditions other than 34 degrees. Likewise, abdominal fat content was significantly increased, and heat production was lower in the groups kept under the hot conditions other than 34 degrees. The rate of skeletal muscle protein turnover and plasma concentration of CTC were decreased when the birds were exposed to hot conditions other than 34 degrees, suggesting a role of CTC in the regulation of muscle protein turnover. Plasma concentrations of T4 and T3 were significantly decreased as environmental temperature increased. These results clearly show that plasma concentrations of thyroid hormones and CTC are associated with accelerated muscle protein turnover and heat production.

Adipose Tissue↗
PubMed1997

Incubation at the nonpermissive temperature induces deficiencies in UV resistance and mutagenesis in mouse mutant cells expressing a temperature-sensitive ubiquitin-activating enzyme (E1).

In temperature-sensitive (ts) mutants of mouse FM3A cells, the levels of mutagenesis and survival of cells treated with DNA-damaging agents have been difficult to assess because they are killed after their mutant phenotypes are expressed at the nonpermissive temperature. To avoid this difficulty, we incubated the ts mutant cells at the restrictive temperature, 39 degrees C, for only a limited period after inducing DNA damage. We used ts mutants defective in genes for ubiquitin-activating enzyme (E1), DNA polymerase alpha, and p34(cdc2) kinase. Whereas the latter two showed no effect, E1 mutants were sensitized remarkably to UV light if incubated at 39 degrees C for limited periods after UV exposure. Eighty-five percent of the sensitization occurred within the first 12 h of incubation at 39 degrees C, and more than 36 h at 39 degrees C did not produce any further sensitization. Moreover, while the 39 degrees C incubation gave E1 mutants a moderate spontaneous mutator phenotype, the same treatment significantly diminished the level of UV-induced 6-thioguanine resistance mutagenesis and extended the time necessary for expression of the mutation phenotype. These characteristics of E1 mutants are reminiscent of the defective DNA repair phenotypes of Saccharomyces cerevisiae rad6 mutants, which have defects in a ubiquitin-conjugating enzyme (E2), to which E1 is known to transfer ubiquitin. These results demonstrate the involvement of E1 in eukaryotic DNA repair and mutagenesis and provide the first direct evidence that the ubiquitin-conjugation system contributes to DNA repair in mammalian cells.

Animals↗
PubMed1995

Salt-induced cell lysis of Staphylococcus aureus.

Cell lysis was efficiently induced in Staphylococcus aureus by the addition of 0.3 M NaCl to exponentially growing cultures at 30 degrees C. When cells harvested at the exponential phase were incubated in buffer with NaCl, autolysis occurred. Treatment with chloramphenicol failed to induce cell lysis by NaCl. The effects of NaCl on growing cells and harvested cells were inhibited by the addition of sodium polyanethole sulfonate, subtilisin, cardiolipin, and lipoteichoic acid. These agents diminished the activity of a cell wall-lytic enzyme liberated from the cells in the presence of NaCl. Lysis induced by salt appears to be catalyzed by a similar lytic enzyme in growing and harvested cells.

Autolysis↗
PubMed1995

Abnormal integrity of the nucleolus associated with cell cycle arrest owing to the temperature-sensitive ubiquitin-activating enzyme E1.

A mouse cell mutant, ts85, containing the temperature-sensitive ubiquitin-activating enzyme was arrested in G2 phase at the non-permissive temperature. In the arrested cells, azure C, a nucleolus-specific stain, revealed a U-shaped or ring-shaped arrangement of nucleolar lobes with an unstained region in the center. Silver staining of the nucleolar organizer region (NOR) and fluorescence in situ hybridization (FISH) with rDNA both gave signals in azure C-positive regions. Electron microscopic examination revealed a cloud of unidentified electron-dense particles (diameter approximately 70 nm) in the azure C-negative center space. When the arrested cells were released into M-phase, we observed the association of NOR-bearing chromosomes with a pulverization-like abnormality. FISH with rDNA and NOR silver staining demonstrated that the pulverization-like abnormality was restricted to NORs. The frequent occurrence of persistent nucleolar material in prophase and prometaphase of the stressed cells after release indicated a delayed dissociation of the nucleolus that brought about the abnormal chromosomes in M-phase. ts85 cells transfected with the mouse E1 cDNA recovered growth at the non-permissive temperature and no longer showed abnormal nucleolar morphology. It seems that the ubiquitin system plays a role in the dissolution of the nucleolus, possibly involving the NOR-bearing chromosomes.

Animals↗
PubMed1995

Ubiquitin-activating enzyme, E1, is phosphorylated in mammalian cells by the protein kinase Cdc2.

The ubiquitin-activating enzyme (E1) is the first enzyme in the pathway leading to formation of ubiquitin-protein conjugates. E1 was found to be phosphorylated in cells of a mouse mammary carcinoma cell line, FM3A. Peptide mapping of trypsin digests of labeled E1 indicated that two oligopeptides were mainly phosphorylated in vivo. The same oligopeptides were also labeled in vitro on Cdc2 kinase-mediated phosphorylation of E1, affinity-purified from the same cell line. The Cdc2 kinase is a key enzyme playing a pivotal role in G2/M transition in the cell cycle. The phosphorylation of one of the two oligopeptides was prominent at the G2/M phase of the cell cycle, and dependent upon the Cdc2 kinase activity in vivo since it was significantly reduced in tsFT210, a mutant cell line deficient in Cdc2 kinase. Mutation analysis indicated that the serine residue at the fourth position of the E1 enzyme was a phosphorylation site of Cdc2 kinase. These findings suggest that E1 is a target of Cdc2 kinase in the cell, implying that the ubiquitin system may be dynamically involved in cell cycle control through phosphorylation of this key enzyme.

Amino Acid Sequence↗
PubMed1993

[A study with diagnostic standard of occult hyperprolactinemia (OHP) and the effect of bromocriptine administration].

It is well known that the transient excessive increase of serum prolactin level is harmful for the mechanism of ovulation or the steroidogenesis of the ovaries. The pathogenesis of latent or occult hyperprolactinemia (OHP) has been investigated recently. The present study was conducted to determine the diagnostic standard of OHP, and to elucidate the efficacy of bromocriptine administration for the treatment of OHP and other ovulatory disturbances. 110 cases of hypothalamic anovulations were selected from 385 cases of infertile patients by the LH-RH and TRH loading tests. Bromocriptine (5mg/day) was administered to all of the subjects for more than three months, and the efficacy of the bromocriptine administration was investigated. Follicular development was observed by transvaginal ultrasonography (mature follicular diameters > or = 20mm), and also luteal function was estimated by the duration of the luteal phase in the BBT charts (high phase > or = 12 days), the mid-luteal serum estradiol (> or = 200pg/ml) and progesterone (> or = 10ng/ml) levels. The subjects were divided into two groups: group A, bromocriptine effective patients (63 cases) and group B, bromocriptine non effective patients (47 cases). The results of the LH-RH and TRH loading tests were compared between these two groups. Serum prolactin levels at 30 min. after TRH loading (PRL30) in group B (61.5 +/- 28.3 vs. 38.0 +/- 19.3ng/ml, p < 0.01). At the cut-off points of 50, 60 and 70ng/ml over in the values of the PRL, the efficacies of the bromocriptine administration were 77.4, 78.9 and 88.5%, respectively. From these facts, it was thought suitable that the diagnostic standard of OHP was PRL30 > or = 70ng/ml, and values of PRL30 from 50 to 70ng/ml were borderline cases of OHP. The efficacy of the bromocriptine administration in the cases without OHP (n = 57) was also investigated. Serum LH levels at 30 min. after LH-RH loading (LH30) were compared between the cases of the bromocriptine effective (n = 22) and non effective (n = 35). As a result, the LH30 of the former was significantly higher than that of the latter (96.5 +/- 64.2 vs. 45.1 +/- 31.5mIU/ml, p < 0.005). In conclusion, the diagnostic standard of OHP was determined as PRL30 > or = 70ng/ml (borderline: 50 > 70ng/ml), and bromocriptine administration was effective not only in cases of OHP, but also in cases of hyperreactivities of LH (so-called endocrinological PCOD).

Anovulation↗
PubMed1993

Protein-losing enteropathy caused by mesenteric vascular involvement of neurofibromatosis.

A 44-year-old man with neurofibromatosis suffered from severe diarrhea and progressive hypoproteinemia. Enteric protein loss was confirmed by an alpha 1-antitrypsin clearance test. An x-ray study showed irregular mucosa in the distal segment of the ileum. Protein loss has subsided after ileocecal resection. Laparotomy and radiological examinations failed to demonstrate neurofibroma or other tumors in the abdomen. The resected ileum revealed marked edema of the wall and a pseudomembranous enteritis-like appearance in the luminal surface. Microscopically, lymphatic vessels in the intestinal wall were dilated. Marked thickening of the intima with spindle cell proliferation was observed in the mesenteric arteries and veins. This finding is consistent with vascular changes in neurofibromatosis. These vascular changes in the mesentery due to neurofibromatosis may cause protein-losing enteropathy by altering the hemodynamic state and microvascular permeability in the intestine.

Adult↗
PubMed1993

Conditional resistance to thymineless death predominantly selects DNA synthesis-deficient mutants of mammalian cells.

Temperature-sensitive growth mutants of the mouse mammary carcinoma cell line FM3A were isolated by selecting survivors of thymidylate starvation for a limited time at the restrictive temperature (39.5 degrees C). Nineteen lines of independent isolates were established and all were found to be deficient in DNA synthesis. Cell-cell hybridization with authentic mutant lines of FM3A demonstrated that the mutants fell into three complementation groups, which were deficient in DNA polymerase alpha or ubiquitin-activating enzyme E1 or both.

Animals↗
PubMed1992

Intron 1 and the 5'-flanking region of the human thymidylate synthase gene as a regulatory determinant of growth-dependent expression.

We have determined the regulatory regions responsible for the growth-dependent expression of the human thymidylate synthase (TS) gene, using a set of minigenes constructed from segments of the human TS gene and the cDNA clone. Each construct was introduced stably into a TS-negative mutant of rat fibroblast 3Y1 cells. By serum-restricted synchronization of the cloned transformant cells, we found that a minigene with the genomic 5'-flanking region and intron 1 without other introns were sufficient for the normal extent and pattern of S-phase specific expression at the levels of both mRNA and enzymatic activity. In contrast, a TS cDNA clone driven by an SV40-based expression vector showed constitutive expression. Insertion of intron 1 into the cDNA clone in the normal location, or replacement of the viral 5'-promoter region of the cDNA clone by the genomic 5'-flanking sequence converted the constitutive expression to the S-phase dependent one, but only partly, that is, coexistence of the two regions were required for the normal expression. Results obtained by nuclear run-on assay suggested that posttranscriptional controls are also involved in this regulation in consistent with our previous results with the bona fide human TS gene.

Animals↗
PubMed1992

tsBN75 and tsBN423, temperature-sensitive x-linked mutants of the BHK21 cell line, can be complemented by the ubiquitin-activating enzyme E1 cDNA.

tsBN75 and tsBN423 are independently isolated temperature-sensitive (ts) mutants of the BHK21 cell line for cell growth. Both tsBN75 and tsBN423 belong to the same complementation group and show G2 block at the nonpermissive temperature. Both were efficiently transformed to ts+ cells with the mouse and human cDNA encoding the ubiquitin-activating enzyme, E1. While no transformants of tsBN423 cells had a DNA content greater than the parental 2C, several ts+ transformants of tsBN75 cells acquired a multiploid DNA content. These data thus demonstrate the function of the human and mouse E1 cDNAs and further suggest that E1 functions in more than one step in cell cycle progression.

Animals↗