Search PubMed⌕ Search

Biomedical subjects

H Kondoh

Publications and source records attributed to H Kondoh.

At least 127 records · Page 7Linked to original sources
PubMed1991

Expression of the chicken 'delta 2-crystallin' gene in mouse cells: evidence for encoding of argininosuccinate lyase.

In the chicken genome, downstream from the delta 1 gene, encoding delta-crystallin, a highly homologous gene called delta 2 is found, but neither its expression nor its function has been clarified. Close similarity of the delta 2 gene to mammalian argininosuccinate lyase (ASL)-encoding genes in organization and deduced amino acid sequence of the encoded protein suggested that this gene may encode chicken ASL. To test this possibility, we cloned the delta 2 gene on a plasmid, introduced it into mouse cells, and assessed expression and ASL activity in comparison with delta 1. We found that delta 2 was expressed well in fibroblastic L cells, which resulted in synthesis of a protein with a size (50 kDa) and antigenicity very close to delta-crystallin, but it was repressed in lens cells in which expression of delta 1 was activated. Transfectant L cell lines expressing delta 2 exhibited significantly higher ASL activity than those without. We conclude that the delta 2 gene codes for chicken ASL, but has a tissue specificity distinct from delta 1 in its expression.

Animals↗
PubMed1991

Histamine H1-receptors on astrocytes in primary cultures: a possible target for histaminergic neurones.

The characteristics of histamine H1-receptors expressed on astrocytes from the cerebral cortex of new born rats were analysed by the [3H]-mepyramine binding assay. The apparent dissociation constant (Kd) was 10.4 nM and the binding capacity (Bmax) of 262 fmol/mg protein. H1-antagonists inhibited the [3H]mepyramine bindings and the isomers of chlorpheniramine showed a stereoselectivity for the inhibition of the bindings. Two distinct populations of cultured astrocytes, type-1 and type-2 astrocytes, were enriched and histamine-induced accumulations of inositol phosphates (IP) and cyclic AMP and histamine-evoked Ca++ signals were examined. Histamine stimulated the accumulation of IP in type-2 astrocytes, but not in type-1 astrocytes. The accumulation of cyclic AMP induced by histamine was observed in type-1 astrocytes, although not in type-2 astrocytes. Histamine-induced Ca++ signals were observed in 17.2% of type-1 astrocytes and in 72.9% of type-2 astrocytes. Histamine-induced Ca++ signals in type-2 astrocytes were antagonized by H1-antagonists, but not by H2- antagonists. Histamine-induced Ca++ signals were classified into 4 patterns, ie. transient, oscillatory, sustained and biphasic. When extracellular Ca++ was omitted or La was added to the extracellular medium, sustained phase of Ca++ signal disappeared and transient and oscillatory patterns were only observed. Phorbol ester inhibited histamine-induced Ca++ signals but pertussis toxin (IAP) and organic voltage dependent Ca++ channel blockers had no effect. Histamine-induced Ca++ elevation appeared initially in processes and then Ca++ wave propagated to the cell soma. Ca++ elevation was observed only in the processes in some cells.

Animals↗
PubMed1991

Spontaneous rupture of intrahepatic artery aneurysm with complicated vascular anomalies.

An 18-year-old man developed a sudden onset of upper abdominal pain with vomiting. Ultrasound and computed tomographic (CT) scans revealed the spontaneous rupture of an intrahepatic artery aneurysm with subcapsular hematoma. A celiac arteriogram demonstrated a ruptured intrahepatic artery aneurysm in the right lobe of the liver, right extrahepatic artery aneurysm, obliteration of gastroduodenal artery, and abnormal flow pattern of the splenic artery. Portal vein phase, using superior mesenteric arteriography, showed portal vein varices and obliteration of the portal trunk. A right hepatic lobectomy was performed. The cut surface of the resected liver revealed a ruptured intrahepatic artery aneurysm with massive hematoma.

Adolescent↗
PubMed1991

Augmentation of antiproliferative activity of CPT-11, a new derivative of camptothecin, by tumor necrosis factor against proliferation of gynecologic tumor cell lines.

The co-operative effects of recombinant human tumor necrosis factor (rH-TNF) and CPT-11, a new derivative of camptothecin, against the proliferation of human gynecologic tumor cell lines were examined in vitro. The ishikawa cells were responsive to rH-TNF, the HHUA cells exhibited a minimal degree of responsiveness to rH-TNF, and the HeLa S3 and Caov-3 cells were unresponsive to rH-TNF. The HHUA, Ishikawa and Caov-3 cells were responsive to CPT-11, and the HeLa S3 cells were relatively sensitive to CPT-11 cytotoxicity. In all four cell lines, rH-TNF at clinically achievable concentrations exhibited synergy with CPT-11. The combination therapy of rH-TNF and CPT-11 will be a new approach against gynecologic cancers.

Antineoplastic Agents, Phytogenic↗
PubMed1991

Embryonic lethality resulting from disruption of both N-myc alleles in mouse zygotes.

The N-myc gene is considered to play a major regulatory role in embryogenesis of the mouse because of its high expression in the organogenesis period and its encoding of nuclear proteins with DNA binding motifs. To elucidate the putative regulatory function of N-myc in embryogenesis, we undertook to inactivate this gene in ES cells. The N-myc alleles were disrupted in ES cells, line E14, by means of homologous recombination of targeting vectors that carry neomycin or hygromycin resistant genes. Homologous recombinants were obtained at the frequency of one in 6 x 10(5) electroporated cells. The inactivated N-myc alleles were transmitted through mouse germ lines. Crosses of heterozygous mice resulted in production of wild-type, heterozygous, and N-myc-null pups and fetuses at a ratio of 1:2:0, indicating embryonic lethality of the homozygotes. ES cells totally deficient in N-myc expression were also obtained by consecutive gene disruption with the use of the targeting vectors, demonstrating the non-essentiality of N-myc expression in the stem-cell state. N-myc-null ES cells offer a valuable tool in chimera analysis to elucidate the requirement for N-myc function in embryogenesis.

Alleles↗
PubMed1990

A retinoic acid responsive gene, MK, produces a secreted protein with heparin binding activity.

MK is a gene whose expression increases transiently during retinoic acid-induced differentiation of embryonal carcinoma cells. MK polypeptide was secreted by differentiating HM-1 embryonal carcinoma cells and by L-cells transfected with an MK cDNA under the control of the beta-actin promoter and Rous sarcoma virus enhancer. MK polypeptide was found to have heparin binding activity. Conditioned medium of the transfected L-cells promoted growth of PC-12 pheochromocytoma cells. These findings support the view that MK polypeptide is a secreted factor involved in regulation of growth and differentiation.

Animals↗
PubMed1990

A mouse embryonic stem cell line showing pluripotency of differentiation in early embryos and ubiquitous beta-galactosidase expression.

For analysis of chimeric mice made by injecting embryonic stem (ES) cells into host blastocysts, it is very desirable if the ES cells have a good cell marker that can distinguish them from host cells. It is ideal if the marker can be easily visualized in every type of cell and tissue throughout the embryogenesis. We tried to produce such ES cell lines by introducing an E. coli beta-galactosidase (beta-gal) gene construct by electroporation. One of the transformant lines (MS1-EL4) showed beta-gal activity in every undifferentiated stem cell. After being induced to differentiate in vitro, cells with various morphologies showed beta-gal activity. We also detected beta-gal activity in a wide variety of tissue elements in solid tumors made by injecting the MS1-EL4 cells into syngeneic mice. Then we produced chimeric embryos by injecting the MS1-EL4 cells into blastocysts and recovering the embryos at various developmental stages. We found that the MS1-EL4 cells contributed to various tissues and expressed beta-gal activity, including not only descendants of the inner cell mass but also the trophectoderm-derived extraembryonic ectoderm.

Animals↗
PubMed1990

Armillaric acid, a new antibiotic produced by Armillaria mellea.

A new antibiotic armillaric acid (2), has been isolated from the cultured mycelia of Armillaria mella (Vahl. ex Fr.) Quel (Trichlometaceae). Its structure was elucidated on the basis of the spectral data. Compound 2 exhibits inhibitory activity against gram-positive bacteria and yeast.

Agaricales↗
PubMed1990

Rapid and transient decrease of N-myc expression in retinoic acid-induced differentiation of OTF9 teratocarcinoma stem cells.

The level of expression of N-myc in mouse teratocarcinoma stem cells is very high. Previous studies have shown that N-myc expression significantly decreases when the stem cells are subjected to long-term induction for differentiation by retinoic acid (RA). We found that in a stem cell line, OTF9, a steep yet transient decrease of N-myc expression takes place much earlier, immediately after induction by RA. To examine whether this decrease is responsible for differentiation, we constructed a gene, miwNmyc, to express N-myc cDNA constitutively and transformed OTF9 cells with this gene construct. Transformants under the constitutive expression of miwNmyc differentiated normally, as judged by morphological changes and by modulation of c-myc, Hox1.1, and laminin B1 expression. Therefore, transient decrease of N-myc expression may be the consequence of RA-induced differentiation, even though it occurs very early in the process. Alternatively, in addition to N-myc decrease, there may be redundant mechanisms which lead to OTF9 differentiation after induction by RA, so that suppression of N-myc decrease is bypassed by at least one other mechanism.

Animals↗
PubMed1990

Functional cooperation of lens-specific and nonspecific elements in the delta 1-crystallin enhancer.

The expression of the chicken delta 1-crystallin gene is primarily regulated by the action of a lens-specific enhancer 1 kilobase long and located in the third intron of the gene (S. Hayashi, K. Goto, T. S. Okada, and H. Kondoh, Genes Dev. 1:818-828, 1987). The 120-base-long core segment is required for the activity of the delta 1-crystallin enhancer but by itself shows no activity. We analyzed the action of the core and adjoining segments of the delta 1-crystallin enhancer by two different approaches: (i) multiplication of the segments to express any cryptic effect and (ii) competition among enhancers for nuclear factors involved in enhancer action. We found that (i) the core defines a strictly lens-specific element, (ii) an adjoining segment defines an element with a broad specificity with regard to cell type, (iii) these elements cooperate in cis within the delta 1-crystallin enhancer, (iv) the multimers of these elements complete with each other and with delta 1-crystallin and simian virus 40 enhancers in trans apparently without sequence specificity but in a fashion reflecting the strength of the enhancers, and (v) the enhancers in trans do not affect the expression of enhancer-free genes, thereby ruling out the possibility of competition for general transcription factors. The last two observations raise the possibility that the enhancer segments interacting with different sequence-specific factors also interact with one other component involved in enhancer action.

Animals↗
PubMed1990

Organization and expression of the chicken N-myc gene.

We cloned the chicken N-myc gene and analyzed its structure and expression. We found that it consisted of three exons with coding regions in exons 2 and 3. Comparison to mammalian N-myc genomic sequence indicated that nucleotide sequences of the 5'-flanking region, noncoding exon 1, and introns were not conserved, but coding and 3' noncoding sequences showed significant homology to mammalian N-myc. Alignment of deduced amino acid sequences of chicken and mammalian N-myc proteins revealed nine conserved domains interrupted by different lengths of nonhomologous sequences. Two of the domains were specific to N-myc proteins, and the other seven were common to c-myc proteins. Northern blot (immunoblot) and in situ hybridization analyses of 3.5-day-old chicken embryos revealed that high-level expression of the N-myc gene was confirmed to certain tissues, e.g., the central nervous system, neural crest derivatives, and mesenchyme of limb buds. In the beak and limb primordia, N-myc expression in the mesenchyme was higher toward the distal end, suggesting possible involvement in positional assignment of the tissue within the rudimentary structures.

Amino Acid Sequence↗
PubMed1990

Holter electrocardiogram monitoring in nephrotic patients during methylprednisolone pulse therapy.

We assessed the effect of intravenous methylprednisolone pulse therapy (IMPT) on cardiac rhythm and electrolyte metabolism in patients with nephrotic syndrome. A total of 25 patients had valid evaluations with continuous ambulatory electrocardiograms, and 20 of these had simultaneous sodium and potassium clearances. No significant difference of frequency in complex ventricular arrhythmias (Lown's grades 3-5) between the control and the therapy period was observed; however, 4 patients showed complex ventricular arrhythmias including ventricular tachycardia (2 patients) during the course of therapy. Fractional excretion of potassium and serum potassium significantly increased from baseline after IMPT. Complex ventricular arrhythmias, sometimes leading to sudden death, might ensue from IMPT. These dysrhythmias may be related to an abrupt change in potassium reflux from the cell.

Adult↗
PubMed1990

[Acute toxicity study of buspirone hydrochloride in mice, rats and dogs].

Buspirone hydrochloride (abbr. to BH), an anxiolytic drug, was examined for its intravenous, subcutaneous or oral acute toxicity using Crj: CD-1 (ICR) mice, Crj: CD (Sprague-Dawley) rats and beagle dogs of both sexes. The results obtained were summarized as follows: 1. Drug-related toxic signs included decreased activity and convulsions accompanied with salivation and opisthotonus in mice and rats treated with BH regardless of administration routes, and tremors and clonic convulsions accompanied with salivation in dogs treated with BH orally. 2. Pathological examinations revealed distention of the stomach in dead rats treated with BH orally, and hypersecretion of gastric juice and alterations (viz. edema, necrosis and petechia) on the superficial mucous membrane in the gastropyloric region in dead dogs treated with BH orally. 3. The cause of death was considered to be due to respiratory insufficiency in every species of animals examined. 4. LD50 values (mg/kg) were as follows: [table: see text] 5. No sex differences were observed in every species of animals regardless of administration routes on the basis of toxicological parameters examined.

Administration, Oral↗
PubMed1990

Acute pseudo-obstruction of the colon (Ogilvie's syndrome) during pregnancy.

A case of colonic pseudo-obstruction (Ogilvie's syndrome) during pregnancy is described. The patient, with placenta previa, was in management of bleeding and also of premature labor. She was successfully treated with conservative measures for the Ogilvie's syndrome, and thereafter underwent a cesarean section only. There had been no recurrence of the pseudo-obstruction after the surgical procedure.

Acute Disease↗
PubMed1990

[A case of juvenile Alzheimer's disease with various neurological features such as myoclonus, showing grumose degeneration in the dentate nucleus].

A case of juvenile Alzheimer's disease with various neurological features such as myoclonus, also showing grumose degeneration in the dentate nucleus was reported. In a 35 year old woman, at first myoclonus, and 5 years later, progressive dementia were found. She, then, fell into apallic syndrome 9 years later, and died of pneumonia at the age of 53. She had no particular family history. Neurological examination disclosed cerebellar ataxia, left hemiparesis, convulsion in addition to myoclonus. Neuropathologically, there were a lot of senile plaques and neurofibrillary tangles in the cerebral cortex. A marked myelin loss in the white matter and a neuronal loss in the basal ganglia were also found. And grumose degeneration in the cerebellar dentate nucleus distinctively characterize the present case. The myoclonus and cerebellar ataxia could be attributed to the grumose degeneration. Two similar cases had been previously reported. Juvenile Alzheimer's disease with grumose degeneration like the present case was considered to be one of the subgroups of Alzheimer's disease.

Alzheimer Disease↗
PubMed1990

[Single dose oral toxicity study of BMY-28100 in juvenile rats and dogs].

In order to investigate the single dose oral toxicity of BMY-28100 in juvenile animals, the drug was administered in single doses to 4-day-old and 14-day-old Crj: CD (SD) rats of both sexes at a dose of 2,000 mg/kg, and to 4-week-old beagle dogs of both sexes at doses of 500, 1,000 and 2,000 mg/kg by oral route. The results obtained are summarized as follows: 1. In rats, decreases of the body weight gain were observed for male and female rats treated with the drug on postnatal day 4 through 5 days and 3 days after dosing, respectively. There were no apparent drug-related toxic signs. No deaths occurred during the observation period. Enlargement of the cecum was found in a few rats of both sexes administered the drug on postnatal day 4 or 14. 2. In dogs, watery-mucous diarrhea observed at 2 to 3 hours after dosing in all dose groups was not dose-related. This finding lasted in some dogs till 4 days after dosing. An increased incidence of emesis was induced in all males at 2,000 mg/kg and all females of all dose groups except one female at 2,000 mg/kg. Body weights increased normally for all dogs, but one male at 1,000 mg/kg showed a transient decrease in food consumption. No drug-related histopathological changes were found. Based upon these results, BMY-28100 at 2,000 mg/kg induced no apparent toxic changes in the present experimental conditions. Therefore, the single dose oral toxicity of the drug in juvenile animals appeared to be very slight and generally similar to that in adults.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗