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T Furui

Publications and source records attributed to T Furui.

At least 19 recordsLinked to original sources
PubMed1998

Two-dimensional zymography for analysis of proteolytic enzymes in human pure pancreatic juice.

Proteolytic enzymes in human pure pancreatic juice (PPJ), which was collected by cannulating the main pancreatic duct using endoscopy, were investigated by two-dimensional zymography (2-DZ). 2-DZ was carried out by combining isoelectric focusing (IEF) in the first dimension with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the second dimension, using gels containing casein or gelatin as a substrate for the proteolytic enzymes. After electrophoresis, the gels were incubated in Triton X-100 followed by incubation at 37 degrees C in Tris buffer (pH 8.5) containing CaCl2. By staining the gels with Coomassie Brilliant Blue (CBB R-250), proteolytic enzymes were detected as clear spots and zones against a blue background. Proteinase inhibitors, such as a cysteine proteinase inhibitor (E-64), a metalloproteinase inhibitor (EDTA), and a serine proteinase inhibitor (Pefabloc SC), were added to PPJ in order to determine the types of proteinases. In patients with pancreatic cancer, spots of molecular weight (Mr) 70,000 and isoelectric points (pI) 5.3-5.5 were clearly detected on the gels containing casein and gelatin, while these spots were not detected in the PPJ from healthy subjects. The proteolytic activities of these spots were strongly inhibited by EDTA and Pefabloc SC but not E-64. These results suggest that the spots of Mr 70,000 and pI 5.3-5.5 in PPJ of pancreatic cancer might be matrix metalloproteinase 2, which is a candidate for tumor-associated proteinase. 2-DZ proved to be a tool for analysis of proteolytic enzymes in PPJ and for the clinical diagnosis of pancreatic cancer.

Aged↗
PubMed1997

Lysophosphatidylcholine stimulates activator protein 1 and the c-Jun N-terminal kinase activity.

Lysophosphatidylcholine (lyso-PC), a natural lipid generated through the action of phospholipase A2 on membrane phosphatidylcholine, has been implicated in atherogenesis and the inflammatory process. In vitro studies have established a role for lyso-PC in modulation of gene expression and other cellular responses including differentiation and proliferation. There is also evidence that lyso-PC may act as an intracellular second messenger transducing signals elicited from membrane-associated receptors. The mechanisms behind the diverse activities of lyso-PC are poorly understood. We report, in this study, that treatment of cultured cells with exogenous lyso-PC, at nontoxic concentrations, potently induced activator protein-1 (AP-1) DNA binding and transcriptional activity independent of well known AP-1 activators, protein kinase C or mitogen-activated protein kinases ERK1 and ERK2. Lyso-PC also activated the c-Jun N-terminal kinase (JNK/SAPK), a recently characterized member of the mitogen-activated protein kinase family, known to activate AP-1. The stimulated JNK and AP-1 activities probably mediate or contribute to some bioactive effects of lyso-PC.

Animals↗
PubMed1997

Magnetic resonance evaluation of uterine malformation with corpus agenesis.

Because no treatment is available and its rare prevalence, uterine fundal agenesis is seldom mentioned in the literature. A woman with uterine corpus agenesis, without other genital tract anomalies, presented with primary amenorrhea and infertility. Gonadotropins and ovarian steroids showed normal cyclic variations. A thorough evaluation, including history, physical examination, and appropriate imaging techniques [hysterosalpingography, ultrasonography and magnetic resonance imaging (MRI)] demonstrated extreme accuracy with MRI in the diagnosis of the anatomic defect. MRI permits noninvasive differentiation of uterine anomalies and may spare the patient's diagnostic laparoscopy.

Adult↗
PubMed1996

Evidence for coupling of phosphotyrosine phosphatase to gonadotropin-releasing hormone receptor in ovarian carcinoma membrane.

BACKGROUND: Gonadotropin-releasing hormone (Gn-RH) receptor (Gn-RHR) has been demonstrated in epithelial ovarian carcinoma (Imai et al., Cancer 1994; 74:2555-61). To examine whether Gn-RHR mediates direct antiproliferative effects, we attempted to determine stimulatory regulation by Gn-RH of phosphotyrosine phosphatase (PTP) activity in plasma membranes isolated from ovarian carcinoma samples. METHODS: Surgically removed ovarian carcinomas were screened for Gn-RHR expression prior to plasma membrane isolation. The phosphotyrosine level was observed by: (1) immunoblotting of membrane extracts with antiphosphotyrosine antibodies, and (2) dephosphorylation from 32P-labeled membrane protein. Membrane PTP activity was determined using the synthetic substrate p-nitrophenyl in a spectrophotometric assay. RESULTS: A Gn-RH analog alone, or guanosine thiotriphosphate (GTP-gamma-S) alone, caused a remarkable loss of phosphotyrosine from a 35-kD protein of the membranes; incubation with a Gn-RH analog and GTP-gamma-S produced a further dephosphorylation of this endogenous protein. The Gn-RH analog buserelin stimulated the PTP activity of the membranes in a dose-dependent manner (P < 0.01). GTP-gamma-S enhanced the stimulatory action of Gn-RH on PTP; GDP-gamma-S reversed the Gn-RH action. A similar stimulation of PTP was observed (P < 0.01) when carcinoma tissue slices were exposed to Gn-RH analog in vivo prior to assay in vitro. CONCLUSIONS: Activation of PTP by Gn-RH stimulated the loss of phosphotyrosine from endogenous proteins through GTP-binding protein within plasma membrane isolated from Gn-RHR-expressing ovarian carcinoma. The antimitogenic action of the hormone may occur by counteracting tyrosine phosphorylation to promote cell growth.

Cell Membrane↗
PubMed1996

Protein degradation in human pure pancreatic juice analyzed by two-dimensional gel electrophoresis.

Two-dimensional gel electrophoresis (2-DE) was used to study protein degradation in human pure pancreatic juice (PPJ) which was collected at 5 min intervals for 20 min by selective endoscopic cannulation of the main pancreatic duct. In PPJ collected from healthy subjects no significant degradation was observed by incubating PPJ at 37 degrees C up to 6 h. By further incubation for 24 h, glycoprotein-1, procarboxypeptidase A-1 and lipase were nearly completely degraded, while alpha-amylase and procarboxypeptidase B-1 were not degraded under these conditions; alpha-amylase became labile in the presence of 1 mM ethylene diaminetetraacetic acid (EDTA) or 10 mM phenyl methyl sulfonyl fluoride (PMSF). Protein degradation was observed by 2-DE of an initial fraction of PPJ collected from patients with chronic calcific pancreatitis (CCP). The 2-DE patterns of subsequent fractions resembled those of PPJ from healthy subjects. The mixture of the last fraction with the initial fraction showed significant protein degradation, inhibited by adding aprotinin. Furthermore, the extent of protein degradation correlated with the dilatation of the main pancreatic duct as a consequence of intraductal stagnation of pancreatic juice. These findings demonstrate that protein degradation in PPJ is accelerated by intraductal activation of serine proteases in the case of patients with CCP. 2-DE of PPJ from patients with CCP provides useful information for the evaluation of intraductal activation of zymogens and the progress of chronic pancreatitis.

Adult↗
PubMed1995

Evidence for tight coupling of gonadotropin-releasing hormone receptors to phosphatidylinositol kinase in plasma membrane from ovarian carcinomas.

Gonadotropin-releasing hormone (Gn-RH) analogs inhibit ovarian cancer cell proliferation in vivo and in vitro. To examine whether Gn-RH receptor (Gn-RHR) mediates direct antiproliferative effects, we attempted to determine inhibitory regulation by Gn-RH of phosphatidylinositol (PtdIns) kinase activity, known to stimulate mitogenic response, in plasma membranes isolated from ovarian carcinoma samples. Ovarian carcinomas surgically removed and cloned cell line SK-OV3 had been screened for Gn-RHR expression prior to plasma membrane isolation. PtdIns kinase activity was measured as phosphorylation of exogenous substrate PtdIns by the purified plasma membranes. Incubation of the plasma membranes isolated from Gn-RHR-positive specimens with [gamma-32P]ATP and PtdIns caused [32P]phosphate incorporation into PtdIns phosphate (PtdInsP) in a time-dependent manner. Concomitant exposure of the membrane preparations to Gn-RH analog buserelin (1 microM) led to a 70% inhibition of the PtdInsP production, when compared to control. After 10 or 15 min of an initial incubation, the addition of analog resulted in similar suppression of PtdIns phosphorylation. This inhibition was dependent on the buserelin dose, and a half-maximal effect occurred at a concentration 0.1 to 1 nM of buserelin. Degradation of the produced PtdInsP in the plasma membranes was not affected by the Gn-RH analog. Similar inhibition of PtdIns kinase activities was observed in membranes prepared from cells that had been pretreated with buserelin (1 microM) for 48 hr prior to assay. These findings demonstrate that PtdIns kinase activity is suppressed by Gn-RH analog in plasma membrane isolated from GnRHR-expressing ovarian carcinomas, suggesting a tight coupling of Gn-RHR to PtdIns. The inhibition of membrane-associated PtdIns kinase by Gn-RHR occupancy may mediate the antimitogenic action of the hormone on human ovarian carcinomas.

1-Phosphatidylinositol 4-Kinase↗
PubMed1995

The study of mitochondrial gene modifications in human placenta.

A quantitative study on the effects of placental senescence on mitochondrial DNA (mtDNA) was carried out by measuring mitochondrial gene mutation, levels of mRNA for the cytochrome c oxidase subunit I (COI) and of mtDNA in normal placental tissues at different stages. Deleted mtDNA, the expression of COI in mitochondria and the amounts of mtDNA per cell were examined by the polymerase chain reaction, northern blot analysis and southern blot analysis, respectively. No accumulation of mutant mtDNA with a 4977 base pair (bp) deletion was detected in the normal placenta during pregnancy. There appeared to be a gradual increase of COI mRNA as pregnancy progressed, while the ratio of mtDNA to total DNA in human placenta tended to decrease with gestation. These results indicate that placental ageing is not associated with the accumulation of mtDNA mutation with the 4977 bp deletion or markedly reduced expression of the mitochondrial genome.

Base Sequence↗
PubMed1995

Purification and characterization of 1,25(OH)2D3 receptor from human placenta.

OBJECTIVE: To characterize the receptor for 1,25-dihydroxycholecalciferol [1,25-(OH)2D3], we purified it from nuclear fractions of human placentae. METHODS: Human placental fractions were concentrated with ammonium sulfate, extracted from hydroxylapatite, and then chromatographed on Sepharcryl S-200 and DEAE-cellulose. RESULTS: The receptor for [1,25(OH)2D3] was purified approximately 1,500-fold. The molecular weight of the receptor was estimated to be 55 K dalton by gel filtration. The receptor fractions showed a dissociation constant (Kd) of 3.0 x 10(-10) mol/l, and adsorbed to the DNA cellulose column. D3 analogs, estradiol, and progesterone had almost no effect on 1,25(OH)2D3 binding. CONCLUSION: These properties of the 1,25(OH)2D3 receptor in human placenta are similar to those of the chicken intestinal 1,25(OH)2D3 receptor.

Female↗
PubMed1995

Ultrasound-detected polycystic ovarian syndrome associated with depleted basal level but enhanced response of gonadotropin.

A patient with ultrasound-detected polycystic ovaries and anovulatory oligomenorrhea had extremely low luteinizing hormone (LH) levels, but a heightened sensitivity to gonadotropin-releasing hormone (GnRH). Of interest is the finding of undetectable basal LH levels. This rare presentation may suggest that polycystine ovarian syndrome (PCOS) features may be a consequence of the increased response of LH, independently on basal levels of LH.

Adult↗
PubMed1994

Gonadotropin-releasing hormone receptor in gynecologic tumors. Frequent expression in adenocarcinoma histologic types.

BACKGROUND: Gonadotropin-releasing hormone (Gn-RH) analogs have been used in the therapy of the endocrine-dependent cancers. The authors attempted to determine the frequency with which Gn-RH receptor (Gn-RHR) is present in gynecological cancers. METHODS: Experiments were performed on gynecologic tumors that had been surgically removed and their cloned cell lines. Gn-RHR was characterized by [3H]Gn-RH binding to plasma membrane preparations. Gn-RHR messenger ribonucleic acid was determined by reverse transcription-polymerase chain reaction using oligonucleotide primers synthesized according to the published human Gn-RHR sequence. RESULTS: High affinity binding sites with nanomolar range of Kd and Gn-RHR mRNA were detected in a high proportion (over 90%) of the specimens from endometrium (6 of 6) and endometrial carcinomas (16 of 17), myometrium (6 of 6) and myomas (4 of 5), epithelial carcinoma (21 of 23), and stromal tumors (3 of 3) of the ovary. There was no substantial Gn-RHR in cervical carcinomas or germ cell-derived tumors of the ovary. Cloned cell lines gave identical results to those obtained in their respective mother tumors. CONCLUSIONS: We detected Gn-RHR in a wide range of the carcinomas and tissues originating from the endometrium and ovary, but not in the uterine cervix or germ cell-derived tumors. The expression of Gn-RH receptor raises the possibility that Gn-RH may play a direct regulatory role in the growth of these carcinomas, and provides a possible point of attack for therapeutic approaches using Gn-RH analogs in these malignancies.

Adenocarcinoma↗
PubMed1994

A putative new proteinous factor negative for stromal growth. Purification and identification from endometrial carcinoma extract.

BACKGROUND: Uterine endometrial carcinoma has been reported to synthesize and secrete some putative mitogens that elicit either a positive or negative proliferation response in endometrial fibroblasts. The purposes of this study were to isolate and to identify the negative growth factor(s) from endometrial carcinoma extract. METHODS: The factor was isolated by a sequence of molecular size exclusion filtration, anion exchange chromatography, gel filtration and Affi-Gel Blue chromatography, followed by NH2-terminal amino acid sequencing. Mitogenicity was determined by [3H]thymidine incorporation into the endometrial fibroblasts. RESULTS: The purification procedure yielded a single active protein band (68 kDa). The protein, purified approximately 20,000-fold, evoked 90% inhibition of [3H]-thymidine incorporation into endometrial fibroblasts in the nanomolar range. This potent growth inhibitor is a previously unidentified protein molecule as revealed by amino acid sequences. CONCLUSIONS: Endometrial carcinoma could produce a new protein that may act as a paracrine factor to suppress the growth of its stroma endometrial fibroblasts.

Amino Acid Sequence↗
PubMed1994

Presence of gonadotropin-releasing hormone receptor and its messenger ribonucleic acid in endometrial carcinoma and endometrium.

In support of a possible clinical use of gonadotropin-releasing hormone (Gn-RH) analogs in the treatment of the endometrial carcinoma, this study was undertaken to establish the presence and characteristics of Gn-RH receptor on endometrial cancer. Materials were human endometrial carcinomas surgically removed and endometrial carcinoma cell lines. Gn-RH receptor was characterized by [3H]Gn-RH binding to plasma membrane preparations. Gn-RH receptor messenger ribonucleic acid (mRNA) was determined by reverse transcription-polymerase chain reaction (PCR) using oligonucleotide primers synthesized according to the published human Gn-RH receptor sequence. Specific Gn-RH binding sites were shown to be present in 16 of 18 well-differentiated and 4 of 7 poorly differentiated adenocarcinoma specimens (Kd = 5.89 +/- 3.59 nM, Bmax = 1.80 +/- 0.95 pmol/mg protein) and cell lines RL95-2 and HHUA with Kd of 2.38 +/- 0.86 nM. The high-affinity binding sites were also detected in six proliferative-phase endometrium (Kd = 4.24 +/- 2.32 nM, Bmax = 2.73 +/- 1.12 pmol/mg protein). Gn-RH receptor mRNA was detected in all endometrial carcinoma and endometrial specimens and cell lines where the specific binding sites were detected, but not in adenomyosis or myometrial samples. The expression of Gn-RH receptor provides a possible point of attack for therapeutic approaches using Gn-RH analogs in this malignancy.

Adenocarcinoma↗
PubMed1994

Gynecologic tumors and symptoms in childhood and adolescence; 10-years' experience.

OBJECTIVES: The advancement of diagnostic imaging evaluations and the earlier occurrence of secondary sexual development prompted us to review our recent experience with genital tract tumors in children. METHODS: We analyzed data for 1938 patients aged less than 18 years who were referred to Gifu University School of Medicine-affiliated Hospitals for the years 1984 through 1993. RESULTS: Of the patients, 145 underwent surgical treatment. Vaginal tumor was seen in 5 patients; 1 endodermal sinus tumor, 1 sarcoma botyroides and 3 Gartner's duct cysts. Two patients with malignant tumor presented only with bloody vaginal discharge; recurrent abdominal pain due to vaginal obstruction was noted in 1 patient with the cyst. Ten had benign tumors in the vulva, presenting with a genital mass. Of 114 ovarian tumors, 3 were diagnosed by antenatal ultrasonographic examinations. Fifty-five had germ cell tumors, 33 had epithelial tumors, and 18 had stromal tumors. The most common symptom was abdominal pain and approximately one-third of girls who complained of abdominal pain had an ovarian tumor. Precocious puberty was noted in 4 girls with stromal tumor. Two of the 23 malignant tumors developed in the vagina and the others originated in the ovary. In 19 patients unilateral salpingo-oophorectomy or local excision was done in an attempt for reproductive organ conservation; 4 cases of advanced stage disease were treated with hysterectomy and/or bilateral salpingo-oophorectomy. Only 3 of the 23 patients with malignant tumor died within 4 years and others are free from disease. CONCLUSIONS: Genital symptoms, even common, alert us to the possibility of a genital tract tumor. The prompt and precise detection of either benign or malignant tumors in children may lead to cure and preservation of fertility with conservative surgery.

Adolescent↗
PubMed1994

Lack of evidence for aromatase expression in human ovarian epithelial carcinoma.

It is controversial whether ovarian epithelial carcinoma possesses steroidogenic enzymes. We investigated aromatase expression in ovarian epithelial carcinoma, and compared it with the normal ovary and placenta. Samples were obtained from an ovarian carcinoma cell line SK-OV-3, ovarian tumour tissues from four patients with epithelial carcinoma and one patient with dysgerminoma. Aromatase enzymatic activity was measured in microsome fractions by quantitating 3H2O released from [1-3H] androstenedione and [3H]oestrone converted from [1,2,6,7-3H] androstenedione. Aromatase messenger ribonucleic acid (mRNA) was determined by reverse transcription-polymerase chain reaction (RT-PCR) using oligonucleotide primers synthesized according to the published human aromatase gene sequence. No aromatase activity was detected in either of two mucinous cystadenocarcinoma specimens or in SK-OV-3 cells, while aromatization proceeded with apparent Michaelis-Menten kinetics in the normal ovaries and placentas. The apparent Km value was 200 nmol/L for the ovary. Aromatase mRNA was detected in dysgerminoma, and the normal ovary and placenta, but not in any of three mucinous cystadenocarcinoma specimens, one serous cystadenocarcinoma specimen and SK-OV-3 cells. These results for both enzyme activity and gene expression suggest that the human ovarian epithelial carcinoma lacks aromatase. The demonstration of absence of aromatase gene expression raises the possibility that aromatase activity in ovaries bearing epithelial carcinoma may be associated with hyperplastic stromal rather than tumour cells.

Adenocarcinoma↗
PubMed1994

Effects of the conventional anticonvulsants, phenytoin, carbamazepine, and valproic acid, on sodium-potassium-adenosine triphosphatase in acute ischemic brain.

The effects of phenytoin, carbamazepine and valproic acid on alterations in sodium-potassium-adenosine triphosphatase activity during ischemia were studied in the rat brain. Pretreatment with phenytoin and carbamazepine prevented a reduction of this activity, which, without either treatment, was observed in the cerebral hemisphere exposed to 30-minute ischemia resulting from unilateral middle cerebral artery occlusion. Valproic acid, on the other hand, did not principally affect the ischemic impairment of this membrane-bound enzyme activity. These results lend support to the previously proposed use of phenytoin in cerebral ischemia, but also suggest the therapeutic availability of another common anticonvulsant, carbamazepine, for treatment of the insult.

Animals↗
PubMed1994

Inhibition by prolactin of membrane-associated phosphatidylinositol kinase of human endometrial fibroblast.

Certain malignant tumors synthesize and secrete a putative peptide mitogen, which elicits a potent proliferative response in their supporting stromal cells. We recently demonstrated that prolactin (PRL) binds to human endometrial fibroblasts and inhibits mitogenicity of an endometrial carcinoma extract (Imai A, et al. Proc Soc Exp Biol Med 203:117-122, 1993). In this report, we have studied inhibitory regulation by PRL of phosphatidylinositol (PtdIns) kinase activity associated with plasma membranes isolated from human endometrial fibroblasts. Incubation of the isolated plasma membrane with [gamma-32P]ATP and exogenous PtdIns caused [32P]phosphate incorporation into PtdIns phosphate (PtdInsP); 95% of the 32P-labeled PtnInsP was accounted for by PtdIns 4-P. The PtdIns phosphorylation by membrane preparations was selectively stimulated in a dose-dependent manner by vanadate, in parallel with an elevated autophosphorylation of endogenous membrane proteins. Concomitant exposure of the membrane preparations to PRL led to a remarkable inhibition of the vanadate-responsive PtdIns phosphorylation and protein autophosphorylation. This inhibition was dependent on PRL dose, and half-maximal effect occurred at a concentration 1-10 nM of PRL. Degradation of the produced PtdInsP in the plasma membranes was not affected by PRL. Similar inhibition of PtdIns kinase activities were observed in membranes prepared from cells that had been pretreated in vivo with PRL prior to assay in vitro. These findings demonstrate that PtdIns kinase activity associated with protein autophosphorylation is suppressed by PRL in plasma membrane isolated from endometrial fibroblasts. The inhibition of vanadate-responsive PtdIns kinase by PRL suggests an involvement of this enzyme in the antimitogenic action of the hormone on human endometrial fibroblasts.

1-Phosphatidylinositol 4-Kinase↗
PubMed1994

Decrease in cytochrome c oxidase and cytochrome oxidase subunit I messenger RNA levels in preeclamptic pregnancies.

OBJECTIVE: To elucidate the possible relation between mitochondrial gene expression and placental dysfunction. METHODS: We measured the activity of cytochrome c oxidase and the expression of cytochrome oxidase subunit I in mitochondria from human placentas of women whose gestations were appropriate for gestational age (AGA) and those with preeclampsia. In addition, the amounts of normal mtDNA and deleted mitochondrial DNA were examined in the two groups by Southern blot analysis and polymerase chain reaction, respectively. RESULTS: Cytochrome c oxidase activity and expression of cytochrome oxidase subunit I were significantly lower in the preeclamptic group than in the AGA group. There were no differences between the groups in the amounts of mitochondrial DNA. In addition, no mutant mitochondrial DNA with a 4977-base pair deletion was detected in the two groups. CONCLUSION: These results suggest that reduced expression of the mitochondrial gene is involved in placental dysfunction in preeclamptic pregnancy.

Actins↗