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Biomedical subjects

A Kume

Publications and source records attributed to A Kume.

89 records · Page 5Linked to original sources
PubMed1989

Isolation of the rat s-myc gene having tumor suppressing activity.

We have isolated a myc related gene, called s-myc, from a rat genomic library using a 32P-labeled fragment of exon 3 of v-myc as a probe. Nucleotide sequencing showed that the s-myc gene contains an open reading frame of 1,287 bp without introns. The s-Myc protein predicted from the DNA sequence has approximately 60% amino acid sequence homology with that of the mouse N-Myc protein. Transfection of the s-myc gene into rat RT4-AC tumor cells induced morphological changes of the cells and suppressed their tumorigenicity in nude mice.

Amino Acid Sequence↗
PubMed1989

[A case of overlap syndrome of PSS, SLE and Sjögren syndrome treated by cyclosporin A: an improvement of sclerosis of the skin].

A 26-year-old female patient complicated with PSS, SLE and Sjögren was treated by combination of medium doses of corticosteroid and cyclosporin A. On admission, she showed many abnormal laboratory findings such as increased serum gammaglobulin level, high anti-DNA antibody titer and low compliment level. This therapy improved not only these laboratory abnormalities but clinical symptoms including sclerosis of the skin and arthritis, without notable side effect due to either of these drugs for the following 10 months so far. On the other hand we haven't acknowledged the effect to internal involvement yet. Since there is no promising therapy to sclerosis of the PSS skin, it is suggested that cyclosporin A can be an effective agent for PSS and should be further evaluated.

Adult↗
PubMed1988

The impaired expression of glycine decarboxylase in patients with hyperglycinemias.

Glycine decarboxylase, a constituent of the glycine cleavage system, in patients with either nonketotic or ketotic hyperglycinemia (NKH and KH) was examined using an anti-chicken glycine decarboxylase antibody. Patients with NKH who have lesion in glycine decarboxylase are differentiated by its expressed level in the liver. One group is cases of the neonatal onset type who have neither activity of the enzyme nor protein reactive to the antibody. The other is a case of the late onset type who shows low but detectable activity of the enzyme and the desirable amount of the immunoreactive material. In the liver of a patient with KH not showing the appreciable activity of H-protein, ubiquitous amount of protein reactive to anti-H-protein IgG is detected and amount of glycine decarboxylase has also been lowered. It is suggested that several mechanisms may be involved in determining the expressed level of glycine decarboxylase in patients with hyperglycinemias.

Adult↗
PubMed1987

Fetomodulin: marker surface protein of fetal development which is modulatable by cyclic AMP.

A novel cell surface marker of fetal development was identified in both in vivo and in vitro systems of the mouse using monoclonal antibodies against a glycoprotein of an apparent size of 133,000 Da. Two independent clones of hybridomas were isolated by fusing murine myeloma cells, NS-1, with spleen cells of a rat which was immunized with murine 3T3 fibroblast. The analysis of molecular size and tryptic peptides of the immunoprecipitate indicated that fibroblast and putative parietal endoderm cells, which were derived by induced differentiation of F9 embryonal carcinoma cells with retinoic acid and cyclic AMP, expressed apparently the same protein. Undifferentiated F9 cells and F9 cells which were treated with retinoic acid or cyclic AMP alone had little or no immunoprecipitable proteins. Analogously, parietal endoderm of in vivo embryos tested positive for this protein but visceral endoderm and embryonic ectoderm did not. The amount of this surface protein was increased in fibroblast and differentiated F9 cells by elevation of intracellular cyclic AMP concentrations. These results are consonant with a hypothesis that this surface protein plays a role in fetal development via a quantitative modulation by cyclic AMP.

Animals↗
PubMed1986

Improved vector, pHSG664, for direct streptomycin-resistance selection: cDNA cloning with G:C-tailing procedure and subcloning of double-digest DNA fragments.

A plasmid cloning vector, pHSG664, has been constructed which is suitable for the direct-selection of transformed cells with recombinant DNAs. The plasmid contains the replicon and ApR-gene region of pUC9 ligated to the strA+ (rpsL+) gene derived from pNO1523 [Dean, Gene 15 (1981) 99-102]. The vector contains ten unique restriction sites: EcoRI, HpaI, PvuII, SphI, PstI, SmaI(XmaI), BamHI, SalI(AccI, HincII), XbaI and HindIII. Five sites (bold-face lettering) are located within the coding region of the strA+ gene. Any insertion at the five bold-faced sites or any nucleotide replacement involving the strA+ gene region and the other unique sites can be selected by Ap and Sm double selection in a strA- (SmR) strain such as E. coli HB101. Thus, this vector is useful for cDNA cloning at either the SphI or the PstI site with the G:C-tailing procedure, as well as for the cloning of double-digest DNA segments.

Base Sequence↗
PubMed1986

[Pancreatic acinar cell carcinoma curatively resected by pancreaticoduodenectomy].

The incidence of acinar cell carcinoma among malignant pancreatic tumors is about 1%, and the prognosis is reported to be poor. We resected an acinar cell carcinoma that had arisen on the pancreatic head by pancreaticoduodenectomy in December 1983. This tumor occupied the pancreatic head, and it measured 10 X 9.5 X 9.5 cm. The microscopic findings showed that the tumor cell was well-differentiated and acinar formation was uniform. The growth of the tumor was expansive, and the lesion was clearly capsulated by fibrous tissue. There was no lymph node metastasis, so the curative operation was performed by the enbloc resection of the tumor. Zymogen granules in the tumor cells were confirmed by electron microscopy. Consequently, we concluded that the origin of the tumor was acinar cells.

Carcinoma↗
PubMed1984

Cyclic diacyl groups for protection of the N6-amino group of deoxyadenosine in oligodeoxynucleotide synthesis.

Three kinds of substituted phthaloyl groups and a succinyl group were introduced onto the N6-amino function of deoxyadenosine derivatives. Among them, the succinyl group was found to be the most effective for prevention of depurination upon detritylation in acidic media and the most stable in basic media. Protection of the N6-amino function of 5'-O-dimethoxytrityldeoxyadenosine and introduction of a succinate linker into the 3'-hydroxyl were achieved simultaneously by a one-step reaction with succinic anhydride. A tetradeoxyribonucleotide, dTpTpTpA containing a 3'-terminal deoxyadenosine was successfully synthesized on a polystyrene support via the phosphotriester method.

Acylation↗
PubMed1983

Mode of cell surface marker changes during retinoic acid-induced differentiation in pluripotent embryonal carcinoma cells.

Pluripotent teratocarcinoma cell line, 311, was cultured in the presence of retinoic acid (RA) and studied for the processes of early marker changes associated with cell differentiation. The cell populations that have lost peanut agglutinin (PNA), Lotus tetragonolobus agglutinin (LTA) or wheat germ agglutinin (WGA) receptor increased in proportion to the period since the start of RA treatment. The kinetics of the appearance of these receptor-negative cell populations suggests that the differentiating cells lose lectin receptors in the order of PNA, LTA and WGA. However, the changes in F9 antigen(s) and LTA receptor occurred at an equal frequency in PNA+ and PNA- cells, indicating that, although the loss of lectin receptors takes place in a distinct order, the change in each receptor itself proceeds independently of the state of other lectin receptors.

Animals↗
PubMed1983

Induction of teratocarcinoma cell differentiation. Effect of the inhibitors of DNA synthesis.

Induction of teratocarcinoma cell (F9) differentiation was studied by using inhibitors of DNA synthesis and several agents known to be differentiation inducers. Inhibition of DNA synthesis induced changes in cell surface marker F9 and stimulated the production of plasminogen activator (PA) in a manner that is dependent upon de novo synthesis of RNA and protein. The results thus indicate close association between inhibition of DNA synthesis and induction of cell differentiation. This approach will be useful in investigating the mechanism of teratocarcinoma cell differentiation.

Animals↗
PubMed1982

Effects of beta-mercaptoethanol-containing medium and feeder cells on the differentiation of embryonal carcinoma cells.

Pluripotent, feeder-dependent teratocarcinoma cell lines were cultured without a feeder layer in a medium containing 10(-4) M beta-mercaptoethanol (beta-medium) and compared for the development of early markers with cells cultured with a feeder layer. The cells cultured in beta-medium lost the PNA (peanut agglutinin) receptor typically at low density. This change was accompanied with enhanced secretion of plasminogen activator and the loss of sensitivity to anti-F9 serum, indicating the stem cell differentiation. In contrast, the cells cultured on a feeder layer did not show any marker changes, thus indicating the lack of differentiation. These results indicate that while the presence of feeder cells inhibits cell differentiation, cultivation in beta-medium permits the differentiation of pluripotent teratocarcinoma cells.

Animals↗
PubMedDate not supplied

A selective amplifier gene for tamoxifen-inducible expansion of hematopoietic cells.

BACKGROUND: We have developed a novel system for expansion of gene-modified hematopoietic stem/progenitor cells to overcome the low efficiency of current gene transfer methodology. This system involves 'selective amplifier genes', that encode fusion proteins between the granulocyte colony-stimulating factor receptor (GCR) and the hormone-binding domain of estrogen receptor (ER). Hematopoietic progenitors expressing the chimeras showed estrogen-responsive growth in a controllable manner. However, endogenous estrogen may activate the fusion proteins in vivo, depending on the hormonal status of the subjects. METHODS: We replaced ER with a mutant receptor (TmR) which specifically binds to 4-hydroxytamoxifen (Tm), to overcome limitations with wild-type ER. Interleukin-3 (IL-3)-dependent Ba/F3 cells and hematopoietic progenitor cells transduced with the resultant fusion proteins (GCRTmR and delta GCRTmR) were examined for ligand-inducible growth. RESULTS: GCRTmR- and delta GCRTmR-expressing Ba/F3 showed IL-3-independent growth in response to Tm, while the cells were unresponsive to estrogen at concentrations up to 10(-7)-10(-6) M. Furthermore, murine bone marrow cells transduced with GCRTmR and delta GCRTmR formed colonies in methyl-cellulose medium in response to Tm, while virtually no colonies appeared with 10(-7) M estrogen or without cytokines. CONCLUSIONS: These results suggest that influences of the endogenous estrogen can be almost eliminated by using the GCRTmR/Tm or delta GCRTmR/Tm system to expand gene-modified hematopoietic stem/progenitor cells.

Animals↗
PubMedDate not supplied

Non-ketotic hyperglycinemia: a life-threatening disorder in the neonate.

Non-ketotic hyperglycinemia (NKH) is a well-recognized metabolic cause of life-threatening illness in the neonate. The fundamental defect is in the glycine cleavage enzyme (GCE), which consists of four protein components. Our study revealed that the majority of NKH patients had a specific defect in P-protein (glycine decarboxylase). The primary lesion of NKH in gene level was investigated, using cDNA encoding human glycine decarboxylase. A three-base deletion; resulting in deletion of Phe756 was found in a Japanese patient with NKH. In the majority of NKH patients in Finland, where there is a high incidence of NKH, it was found to be due to a common mutation--a point mutation resulting in amino acid alternation from Ser564 to Ile564. Prenatal diagnosis is possible by determining the activity of GCE and also by DNA analysis. Recent findings suggest that the high concentrations of glycine in the brain may contribute to the pathophysiology of NKH by overactivating NMDA receptors via an action at the associated glycine modulatory site. These provide a possibility that early treatment with NMDA receptor antagonist may prevent brain damage in NKH.

Amino Acid Oxidoreductases↗
PubMedDate not supplied

Autoradiography of L-type and N-type calcium channels in aged rat hippocampus, entorhinal cortex, and neocortex.

The present study examined brains from 6, 17, and 32 month old male (F344x BN)F1 rats to determine whether there was any age-related change in the distribution or density of L-type and N-type Ca2+ channels in hippocampus, entorhinal cortex, and neocortex, areas commonly involved in the generation of epileptic seizures. The L-type channel antagonist PN200-110 and the N-type channel antagonist omega-conotoxin GVIA were used to determine specific binding densities and the autoradiographic distribution of ligand binding was quantified by computer-assisted densitometry. One-way ANOVA noted a significant variance in the mean value of binding density between different age groups only in neocortex laminae IV-VI for [(3)H]PN200-110 binding (P < 0.05). Post-hoc testing indicated that the mean value of the 17 month old group was significantly less than those of the 6 and 32 month old groups (P < 0.05). These results indicate no overall age-related change in the number of L-type and N-type Ca2+ channels in brain areas frequently involved in seizure activity and suggest that age-related changes in brain Ca2+ physiology may be associated with changes in voltage-gated Ca2+ channel function rather than channel number.

Age Factors↗
PubMedDate not supplied

Gene transfer into rat renal cells using adeno-associated virus vectors.

Adeno-associated virus (AAV) vectors have a number of attractive features, including lack of cytotoxicity, ability to transduce nondividing cells, and long-term transgene expression. We investigated whether rat renal cells could be efficiently transduced with AAV vectors. Rat glomerular mesangial cells were transduced with AAV-lacZ vector containing beta-galactosidase gene in vitro, and the expression of beta-galactosidase was evaluated by X-gal staining and ELISA. For ex vivo experiments, sections of rat kidneys were incubated with AAV-lacZ, and then evaluated by X-gal histochemical staining. The level of beta-galactosidase expression in cultured rat mesangial cells increased in a dose-dependent manner (ranging from 1 x 10(5) to 5 x 10(6) particles/cell). When transduced with 5 x 10(6) vector particles/cell of AAV-lacZ, about 50% of mesangial cells were stained positively with X-gal, and the level of beta-galactosidase expression reached 9.9 +/- 1.5 ng/mg protein. Expression was detectable during the culture period for at least 7 days. X-gal histochemical examination of the ex vivo transduced renal tissue revealed tubular cell and interstitial tissue staining. However, gene transfer was not clearly observed in glomeruli. These findings suggest that AAV vectors have the potential for gene therapy of renal diseases.

Animals↗
PubMedDate not supplied

Asymmetrical FDG-PET and MRI findings of striatonigral system in multiple system atrophy with hemiparkinsonism.

The asymmetry of the local cerebral metabolic rate for glucose (lCMRglc) and magnetic resonance (MR) imaging was studied in five patients with multiple system atrophy (MSA) presenting hemiparkinsonism. lCMRglc was measured with 18F-2-fluoro-2-deoxy-D-glucose and positron emission tomography (PET) in these patients and five normal control subjects. MR images were obtained in five patients and 11 control subjects. In all patients, T2-weighted MR images showed hypointense areas in the posterior lateral putamen. They were bigger or lower in intensity on the contralateral side than on the ipsilateral side. Significant glucose hypometabolism was found in the posterior putamen on the contralateral side to hemiparkinsonism. A significant decrease in size was found in the contralateral putamen, caudate nucleus, and pars compacta of the substantia nigra. However, no significant correlation was seen between PET and MRI data. In the control subjects, no apparent asymmetry was observed. PET and MR imaging demonstrated the characteristic asymmetry corresponding to the pathological findings reported in MSA.

Brain↗