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Biomedical subjects

I Fujino

Publications and source records attributed to I Fujino.

14 recordsLinked to original sources
PubMed1997

Transient decrease of HPC-1/syntaxin-1A mRNA in the rat hippocampus by kainic acid.

HPC-1/syntaxin-1A is a neuronal protein of which the mRNA has an immediate early gene-like structure in its 3'-untranslated region. Whereas HPC-1/syntaxin-1A protein plays a crucial role in neurotransmitter release, little is known about HPC-1 gene expression. We demonstrate here that HPC-1 mRNA expression in rat hippocampal neurons in vivo decreased 8 h after kainic acid (KA) administration, but was restored thereafter. The transient decrease of HPC-1 mRNA upon KA administration suggests that the HPC-1 mRNA expression in neurons could be altered by excitation by trans-synaptic stimulation.

Animals↗
PubMed1995

Differential expression of type 2 and type 3 inositol 1,4,5-trisphosphate receptor mRNAs in various mouse tissues: in situ hybridization study.

The inositol 1,4,5-trisphosphate receptor (IP3R) is an intracellular Ca2+ release channel responsible for mobilizing stored Ca2+. Three different receptor types have been molecularly cloned, and their genes have been classified into a family. The gene for the type 1 receptor (IP3R1) is predominantly expressed in cerebellar Purkinje neurons, but its gene product is localized widely in a variety of tissues; however, there is little information on what types of cells express the other two receptor types, type 2 and type 3 (IP3R2 and IP3R3, respectively). We studied the expression of the IP3R gene family in various mouse tissues by in situ hybridization histochemistry. Compared with IP3R1, the levels of expression of IP3R2 and IP3R3 mRNAs were low in all of the tissues tested. IP3R2 mRNA was localized in the intralobular duct cells of the submandibular gland, the urinary tubule cells of the kidney, the epithelial cells of epididymal ducts and the follicular granulosa cells of the ovary, while the IP3R3 mRNA was distributed in gastric cells, salivary and pancreatic acinar cells and the epithelium of the small intestine. All of these cells which express either IP3R2 or IP3R3 mRNA are known to have a secretory function in which IP3/Ca2+ signalling has been shown to be involved, and thus either IP3R2 or IP3R3 may be a prerequisite to secretion in these cells.

Animals↗
PubMed1994

Human inositol 1,4,5-trisphosphate type-1 receptor, InsP3R1: structure, function, regulation of expression and chromosomal localization.

We have isolated cDNA clones encoding an inositol 1,4,5-trisphosphate receptor type 1 (InsP3R1) from human uteri and a leukaemic cell line, HL-60. Northern-blot analysis showed that approx. 10 kb of InsP3R1 mRNA is expressed in human uteri, oviducts and HL-60 cells. The predicted amino acid sequence of human InsP3R1 (2695 amino acids) has 99% identity with that of the mouse SI-/SII- splicing counterpart. Western-blot analysis with anti-(mouse InsP3R1) antibodies showed that InsP3R1 protein of human uteri and oviducts of approx 220 kDa is immunostained. Northern-blot analysis of HL-60 cell differentiation along the neutrophilic lineage induced by retinoic acid or dimethylsulphoxide showed an accompanying enhanced expression of InsP3R1 mRNA. Immunohistochemical analysis of the cerebella of spinocerebellar degeneration patients showed a variable loss of Purkinje cells with an altered pattern of immunostaining. The InsP3R1 gene (Insp3r1) was localized to the 3P25-26 region of human chromosome 3. The data presented here clearly show that InsP3R1 exists widely in human tissues and may play critical roles in various kinds of cellular functions.

Adult↗
PubMed1994

Correlation of p53 with the clinicopathologic features and prognosis of colorectal adenocarcinoma.

Immunohistochemical staining of p53 was performed using an anti-p53 mouse monoclonal antibody, Pab1801, on 67 colorectal adenocarcinoma specimens to determine the prognostic value of p53 in colorectal cancer patients. Of a total of 67 tumors examined, p53 was detected in 34, but the rate of positive staining for p53 did not correlate with the clinical stage of disease. In 59 patients undergoing curative resection of the tumor, there was no significant difference in the recurrence rate (P = 0.137) or the disease-free survival rate between 28 patients with p53 positive tumors and 31 with p53 negative tumors (P = 0.135).

Adenocarcinoma↗
PubMed1993

Inositol trisphosphate receptor and Ca2+ signalling.

Inositol 1,4,5-trisphosphate (InsP3) is a second messenger that releases Ca2+ from the intracellular stores. The InsP3 receptor (InsP3-R) was purified and its cDNA was cloned. We have found that InsP3-R is identical to the P400 protein identified as a protein enriched in the cerebellar Purkinje cells. We generated an L fibroblast cell transfectant that produced cDNA derived InsP3-R. The expressed protein displays high affinity and specificity for InsP3. InsP3 induces Ca2+ release from the membrane vesicles of the transfected cells. Incorporation of purified InsP3-R into a lipid bilayer showed InsP3 induced Ca2+ release. These result suggest that InsP3-R is a Ca2+ release channel. Immunogold method using monoclonal antibodies against the receptor showed that it is highly condensed on the smooth surfaced endoplasmic reticulum (ER) and slightly on the outer nuclear membrane and rough ER. Cross linking experiments show that the InsP3-R forms a homotetramer. The approximately 650 N-terminal amino acids are highly conserved between mouse and Drosophila melanogaster, and this region has the critical sequences for InsP3 binding. We found novel subtypes of the InsP3-R resulting from RNA-splicing that are expressed in a tissue-specific and developmentally specific manner and also resulting from different genes. It is believed that there are two Ca2+ release mechanisms, InsP3-induced Ca2+ release (IICR) and Ca(2+)-induced Ca2+ release (CICR). Eggs are good materials to analyse the machanism of Ca2+ signalling: fertilized hamster eggs exhibit repetitive Ca2+ transients as well as the Ca2+ wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Widespread expression of inositol 1,4,5-trisphosphate receptor type 1 gene (Insp3r1) in the mouse central nervous system.

The expression of inositol 1,4,5-trisphosphate receptor type 1 (InsP3R1) in the mouse central nervous system (CNS) was studied by in situ hybridization. The receptor mRNAs were widely localized throughout the CNS, predominantly in the olfactory tubercle, cerebral cortex, CA1 pyramidal cell layer of the hippocampus, caudate putamen, and cerebellar Purkinje cells, where phosphoinositide turnover is known to be stimulated by various neurotransmitter receptors. In the most abundantly expressing Purkinje cells, InsP3R1 mRNA appeared to be translocated to the distal dendrites, since a strong hybridization density was observed in the molecular layer of the cerebellum. InsP3R protein is known to form tetrameric receptor-channel complex. Our preliminary hybridization data using probes for three distinct InsP3R subtypes showed preferential expression of InsP3R1 in many parts of the CNS. The expression of other receptor subtypes (InsP3R2 and InsP3R3) is less efficient, suggesting that a homotetramer formed of InsP3R1 subtype may play a central part in InsP3/Ca2+ signalling in the neuronal function, whereas a homotetramer of other subtypes and a possible heterotetramer among subtypes may be involved in differential InsP3/Ca2+ signalling. The chromosomal localization of the gene coding for InsP3R1 was confirmed on chromosome 6 but was found to be genetically independent of the Lurcher (Lc) mutation.

Animals↗
PubMed1993

[DNA flow cytometry in smooth muscle tumors of the gastrointestinal tract].

DNA ploidy of 45 smooth muscle tumors of the G.I. tract was determined by flow cytometry and correlated with clinical features and prognosis. The sites of the tumors were: esophagus (1), stomach (24), small intestine (12), large intestine (6), liver (1) and pancreas (1). The histologic type was leiomyoma in 14, leiomyosarcoma in 29, and leiomyoblastoma in 2. DNA aneuploidy was more frequent in leiomyosarcoma (17/29) than leiomyoma (5/14), but the difference was not statistically significant. One leiomyoblastoma was diploid and the other was aneuploid. No patients with leiomyoma died. In patients with leiomyosarcomas, 5-year survival was significantly poorer in those with aneuploid tumors (38%) than in those with diploid tumors (83%). There was no correlation between DNA ploidy and clinico-pathological features of tumors. The present study disclosed that DNA ploidy is a prognostic variable, independent of other variables.

Adult↗
PubMed1991

Striking homology of the 'variable' N-terminal as well as the 'conserved core' domains of the mouse and human TATA-factors (TFIID).

A complementary DNA (cDNA) encoding a mouse TFIID (mIID) was isolated from mouse brain cDNA libraries. The 316 amino acid sequence deduced from cDNA sequences revealed the presence of an amino-terminal region enriched in serine, threonine, and proline (STP-cluster), an uninterrupted stretch of 13 glutamine residues (Q-run), a second STP-cluster, and a conserved carboxy-terminal region. Amino acid sequences of the first STP-cluster and the conserved carboxy-terminal region were identical to those of the human TFIID (hIID). However, the Q-run was considerably shorter than that in hIID and sequences in the second STP-cluster diverged from those of the hIID. The murine TFIID transcript is expressed as a 2 kilobase poly(A)+ RNA in the mouse brain. Southern blot analysis identified a single gene copy per haploid mouse genome.

Amino Acid Sequence↗
PubMed1990

Hepatoblastoma in neonates: report of a case and review of the Japanese literature.

A female infant who presented with abdominal distention and jaundice at the age of 2 days underwent resection of a large hepatoblastoma at the age of 8 days by a right trisegmentectomy. Although postoperative adjuvant chemotherapy was not given, the patient is now alive without disease 10 months after surgery. We were able to find only 10 other cases of hepatoblastoma occurring in the newborn period in the Japanese literature. Resection of the tumor was performed in seven of these patients, of whom there were five survivors, one operative death and one death due to tumor recurrence. However, none of the three patients treated conservatively survived. Thus, we suggest that in newborns with hepatoblastoma, resection of the tumor should be performed, if feasible, but believe that postoperative chemotherapy is not necessary for patients whose tumor has been completely resected.

Carcinoma, Hepatocellular↗
PubMed1990

Reliable transient promoter assay using fluorescein-di-beta-D-galactopyranoside substrate.

The promoter region of the mouse myelin proteolipid protein (PLP) gene was cloned into a promoter testing vector, pIP111. The pIP111 vector is a promoterless derivative of pCH110 (SV40 early region promoter-lacZ) and contains the Escherichia coli lpp transcription terminator sequence at the 5' end of the cloning site. The newly constructed PLP-lacZ fusion plasmid (pWP) was transfected into PLP-nonproducing NIH-3T3 fibroblasts or PLP-producing C6 cells. When the measured beta-galactosidase activity in the pWP-transfected cells was normalized to the pCH110-transfected cells (an appropriate control if the SV40 early region promoter functions constitutively in various cell lines), the results suggested that the promoter region of the PLP gene contains the information necessary for initiation of transcription in a C6 cell-specific manner. However, the beta-galactosidase produced in viable cells was also detected by fluorescein-di-beta-D-galactopyranoside (FDG) treatment followed by image analysis using inverted fluorescent microscopy, which allowed the transfection efficiency to be calculated, and the beta-galactosidase activity obtained by the regular ONPG method was normalized with the value obtained. This procedure indicated that the promoter region of the PLP gene did not show C6-specific expression, because the SV40 early-region promoter was 10 times more active in NIH-3T3 cells than in C6 cells. Thus, the standard experiment gave misleading results. As our detection method is simple and can be used to analyze the promoter activity in a single cell, many applications should be possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗