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I Sato

Publications and source records attributed to I Sato.

At least 19 recordsLinked to original sources
PubMed2003

Stimulatory effect of prostaglandin F(2alpha) on Na-dependent phosphate transport in osteoblast-like cells.

Prostaglandin F(2alpha) (PGF(2alpha)) has been reported to activate protein kinase C (PKC) through both phospholipase (PL) C and D, resulting in the proliferation of osteoblast-like cells. In addition, it has also been reported that Erk mitogen-activated protein kinase is also involved in the mechanism of PGF(2alpha)-induced proliferation of these cells. Recently, we have reported that several growth factors stimulate Na-dependent phosphate transport (Pi transport) activity of osteoblast-like cells, which has been recognized to play an important role in their mineralization. In the present study, we investigated the effect of PGF(2alpha) on Pi transport in MC3T3-E1 osteoblast-like cells. PGF(2alpha) stimulated Na-dependent Pi transport dose dependently in the range between 1nM and 10 micro M in MC3T3-E1 cells. The effect was time dependent up to 24h. Kinetic analysis revealed that PGF(2alpha) induces newly synthesized Pi transporter. Pretreatment with actinomycin D and cycloheximide suppressed PGF(2alpha)-induced enhancement of Pi transport. Combined effect of PMA and PGF(2alpha) was not additive in Pi transport. Calphostin C, a PKC inhibitor, dose-dependently suppressed Pi transport induced by PGF(2alpha). On the contrary, U0126, which inhibits an upstream kinase of Erk (MEK), did not affect PGF(2alpha)-induced enhancement of Pi transport. In conclusion, PGF(2alpha) stimulates Pi transport through activation of PKC in osteoblast-like cells.

3T3 Cells↗
PubMed2003

Hofbauer cell activation and its increased glucose-6-phosphate dehydrogenase activity in second trimester-spontaneous abortion: an ultrastructural dual staining enzyme-cytochemical study.

PROBLEM: While activated/phagocytosing phagocytes infiltrating to the chorioamnion are considered to be one of the causal agents of preterm labor onset, whether placental villous macrophages (Hofbauer cells) are activated/phagocytosing in this condition is not known. METHOD OF STUDY: We concomitantly localized two important phagocytosis-related enzymes, acid phosphatase (ACP) and glucose-6-phosphate dehydrogenase (G6PD), in Hofbauer cells in second trimester placental villi, and compared them with those from infection-related second trimester-spontaneous abortion (miscarriage) placentas. RESULTS: There were two types of Hofbauer cells. The first cells exhibited ACP stainings confined to the lysosomes, suggesting that they are dormant/non-activated cells. Approximately two-thirds of these cells showed weak G6PD labeling on the cytosolic side of endoplasmic reticula, and G6PD labeling was hardly recognizable in the remaining one-third. The second cells, possessing large phagosomes, showed marked ACP labeling in the phagosomes, suggesting that they are activated/phagocytosing cells. All these cells exhibited G6PD labeling, and in 'bursting cells' (possibly hyperactivated cells) G6PD deposits were marked. The percentage of activated cells in miscarriage placentas was significantly higher (44.8 +/- 6.0%) than that in gestational age-matched controls (17.4 +/- 5.3%). CONCLUSIONS: These observations indicated that (1) G6PD activity increased in activated/phagocytosing Hofbauer cells, and (2) the percentage of phagocytosing cells increased in infection-related miscarriage placentas. Hofbauer activation and G6PD may play an role in the pathogenesis/pathophysiology of preterm labor onset.

Abortion, Spontaneous↗
PubMed2003

Lipopolysaccharide inhibits luteinizing hormone release through interaction with opioid and excitatory amino acid inputs to gonadotropin-releasing hormone neurones in female rats: possible evidence for a common mechanism involved in infection and immobilization stress.

Acute immobilization stress suppresses naloxone- and N-methyl-d-aspartate (NMDA)-induced, but not gonadotropin-releasing hormone (GnRH)-induced, luteinizing hormone (LH) release in ovariectomized oestrogen-primed rats. To explore whether a common mechanism may underlie inhibition of gonadotropin secretion by various stressors, we examined in the present study the effect of lipopolysaccharide (LPS) on LH release induced by progesterone, GnRH, naloxone and NMDA. The effect of LPS on Fos expression in GnRH neurones was also examined in association with its effect on steroid-induced LH release. Injection of progesterone (1 mg/rat) at noon induced an LH surge in the afternoon in ovariectomized rats pretreated with oestradiol benzoate. In these rats, the majority of hypothalamic GnRH neurones expressed Fos in the evening. Intravenous (i.v.) administration of LPS (10 micro g/rat) inhibited steroid-induced LH release and also reduced the Fos expression in GnRH neurones. In separate experiments, an i.v. injection of GnRH (50 ng/kg), naloxone (10 mg/kg) or NMDA (20 mg/kg) significantly elevated serum LH concentrations within 10 min. Pretreatment with LPS, which did not affect basal LH release or GnRH-induced LH release, inhibited naloxone-induced and NMDA-induced LH release. These results show that LPS has a suprapituitary site(s) of action to suppress the activity of GnRH neurones in female rats, and suggest that LPS affects the opioid, as well as the excitatory amino acidergic regulation of GnRH neurones. The similarity of effects of LPS and immobilization stress further suggests that a common mechanism is involved in inhibition of GnRH neurones by different stressors.

Animals↗
PubMed2003

Modulation of human c-mpl gene expression by thrombopoietin through protein kinase C.

The c-Mpl, thrombopoietin (TPO) receptor specificially controls megakaryocytic growth and differentiation. TPO increased the c-mpl promoter activity determined by a transient expression system using a vector containing the luciferase gene as a reporter in the human megakaryoblastic cell line CMK. The maximal promoter activity of c-mpl was obtained 24 hr after pretreatment with TPO for 3 hr and then declined with time. This increase was completely abolished by protein kinase C (PKC) inhibitors (GF109203, calphostin C and H7). Phorbol 12-myristate 13-acetate (PMA) treatment led to an increase in c-mpl promoter activity. These results demonstrate that the promoter activity of c-mpl is modulated by transcription through a PKC-dependent pathway.

Cell Line↗
PubMed2002

Intrauterine death of one twin, with rescue of the other, in twin-twin transfusion syndrome.

Single intrauterine death may occur in twin-twin transfusion syndrome. We investigated why the outcome of the surviving twin is fairly good when the donor twin dies first compared with when the recipient twin dies first. A detailed hemodynamic study was performed using Doppler ultrasound in a twin pregnancy affected by twin-twin transfusion syndrome before and after a single intrauterine death that occurred in the donor twin at 26 weeks' gestation. The recipient twin was expected to die due to severe right cardiac failure with functional stenosis of the pulmonary artery 2 days before the cotwin's death. The donor twin's death caused a prompt resolution of cardiac failure and improvement in other indices, including flow velocity waveform patterns of the umbilical vein, the middle cerebral artery and the ductus venosus. A healthy, premature female neonate weighing 1630 g with a hemoglobin concentration of 17.8 g/dL was delivered by Cesarean section following rupture of the fetal membranes 28 days after the episode. Hemorrhaging from the surviving twin to the dead twin that occurred just before or after the cotwin's death may have contributed to the decrease in volume overload in the recipient twin, leading to a prompt amelioration of the critical hemodynamic indices. The early death of the donor twin may thus have played a significant role in improving the status of the recipient twin in this case of twin-twin transfusion syndrome.

Adult↗
PubMed2002

Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study.

Glucose-6-phosphate dehydrogenase (G6PD) is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly-developed enzyme-cytochemistry (copper-ferrocyanide) method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithelial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture.

Animals↗
PubMed2001

Problems with peritoneal cytology in second-look laparotomy performed in patients with epithelial ovarian carcinoma.

BACKGROUND: The recurrence rate of ovarian carcinoma is high even when a second-look laparotomy (SLL) is negative. In the current study, the accuracy of peritoneal cytology as an evaluation method of SLL was examined. METHODS: The positive SLL rate and the diagnostic accuracy of peritoneal cytology were evaluated in 101 patients with epithelial ovarian carcinoma. RESULTS: Twenty-three of the 101 patients (23%) were positive based on SLL. The factors considered to be high risk factors for a positive SLL were advanced disease (Stages III and IV by the International Federation of Gynecology and Obstetrics [FIGO] classification), serous adenocarcinoma, and maximum residual tumor > 2 cm after primary surgery (P < 0.05). Of the 23 patients found to be positive on SLL, peritoneal cytology was positive in 6 patients, in whom the percentage was low (26%). The remaining 17 patients (74%) demonstrated false-negative cytology. Of these 17 patients, the tumor tissues were found to be capsulated completely with connective tissues in all biopsy specimens from 9 patients (53%) and in all but 1 biopsy specimen in 6 patients (35%), together accounting for a capsulation rate of 88%. Conversely, clear exposure of the tumor tissues was observed in at least two biopsy specimens in those patients demonstrating positive cytology (P < 0.01). CONCLUSIONS: Peritoneal cytology in SLL was found to result in a high false-negative rate. One of the reasons for this was considered to be capsulation of the lesions with proliferated connective tissues, which may have been the result of by chemotherapy.

Adult↗
PubMed2001

Asymmetric synthesis with a chiral catalyst generated from asymmetric autocatalysis.

A new and efficient one-pot system of asymmetric catalysis is presented in which a chiral catalyst (5-pyrimidyl alkanol) self-improves its ee by asymmetric autocatalysis and then acts as a highly enantioselective chiral catalyst for other asymmetric synthesis (addition of dialkylzincs to aldehydes) to provide products (sec-alcohols) with very high ee (up to 99%).[reaction: see text]

Journal Article↗
PubMed2001

A dot-blot-immunoassay for semen identification using a polyclonal antibody against semenogelin, a powerful seminal marker.

Among various seminal plasma proteins, semenogelin (Sg), produced in the seminal vesicle, has been considered a candidate for demonstrating the presence of semen. Sg consists of two proteins, one 52 kDa (Sg-I) in size, and the other a mixture of 71 and 76 kDa proteins (Sg-II). Recombinant Sg-I and Sg-II proteins were obtained using a baculovirus system and then injected into a rabbit to produce the respective antibodies [Characterization of recombinant precursor proteins of the human seminal plasma sperm motility inhibitor synthesized in insect cells, Int. J. Mol. Med. 2 (1998) 693]. When liquefied seminal plasma was immunoblotted with the anti-Sg-I and Sg-II antibodies, the anti-Sg-II antibody identified a wider range of the polypeptides originating from Sg than did the anti-Sg-I antibody. A dot-blot-immunoassay using anti-Sg-II antibody revealed a clear immunoreactive spot even when the semen was diluted 6400-fold. However, this assay showed that the Sg antigen was undetectable in saliva, urine, vaginal secretions, sweat, nasal secretions and serum. To determine the stability of Sg antigenic activity, filter paper with dried semen stains were kept at 37, 4 and 22 degrees C for 1, 6 and 18 months, respectively, and the Sg antigenic activity was examined. The activity was detectable in an area not less than 0.5 cm x 0.5 cm under all of the above environmental conditions during each period. Finally, semen was mixed with saliva or blood at various volumetric ratios, and used as a source of dried stains. The Sg antigenic activity was detectable in the stains until the ratio of semen to saliva or blood reached 1:8. These results suggest that Sg may be useful as a marker for semen identification.

Adult↗
PubMed2001

Identification of human liver diacetyl reductases by nano-liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry.

Several forms of diacetyl-reducing enzyme were found to exist in the human liver cytosol. Three (DAR-2, DAR-5, and DAR-7) of them were purified as a single band on SDS-PAGE by a combination of a few kinds of column chromatographies. The in-gel tryptic digests of the purified enzymes were analyzed by nano-liquid chromatography (LC)/Fourier transform ion cyclotron resonance mass spectrometry (FT ICR MS), which provided peptide masses at a ppm-level accuracy. The enzymes, DAR-2, DAR-5, and DAR-7, were identified as alcohol dehydrogenase beta subunit (ADH2), carbonyl reductase (CBR1), and aldehyde reductase (AKR1A1), respectively, by peptide mass fingerprinting. In addition, an alternating-scan acquisition of nano-LC/FT ICR mass spectra, i.e., switching of normal acquisition conditions and in-source fragmentation conditions scan by scan, provided sets of parent and fragment ion masses of many of the tryptic peptides in a single LC/MS run. The peptide sequence-tag information at the ppm-level accuracy was used to further confirm the protein identities. It was demonstrated that nano-LC/FT ICR MS can be used for rigorous protein identification at a subpicomole level as an alternative technique to nano-LC/MS/MS.

Acetoin Dehydrogenase↗
PubMed2001

Are DNA mismatch repair deficiencies responsible for accumulation of genetic alterations in epithelial ovarian cancers?

To investigate the association of DNA mismatch repair deficiencies in the development and/or progression of epithelial ovarian cancers, the relationship between replication errors (RERs) and genetic alterations in three genes (p53, c-erbB2, K-ras) and loss of heterozygosity (LOH) on 6q27 was investigated in 70 patients with epithelial ovarian cancers. The presence of RERs was examined by PCR using five microsatellite markers. Mutations of p53 were analyzed by PCR-SSCP and sequencing. Amplification of c-erbB2 was analyzed by Southern blot hybridization. Point mutations of K-ras codon 12 were identified by PCR-PHFA, while 6q27LOH was examined by Southern blot hybridization. As a result, 18 of 70 patients with epithelial ovarian cancers (26%) were RER-positive and 52 patients (74%) were RER-negative. Tumors with two or three genetic alterations accounted for 28% and 33% of RER-positive tumors, respectively, and these were significantly more frequent than in the RER-negative tumors (17% and 6%, respectively)(P =.002). These results are consistent with mismatch repair deficiencies being involved in the development and/or progression of a proportion of epithelial ovarian cancers through accumulation of genetic alterations.

Adenocarcinoma↗
PubMed2001

Asymmetric autocatalysis and the origin of chiral homogeneity in organic compounds.

The discovery and development of asymmetric autocatalysis, in which the structures of the chiral catalyst and the chiral product are the same, are described. Chiral 5-pyrimidyl, 3-quinolyl, and 5-carbamoyl-3-pyridyl alkanols act as highly enantioselective asymmetric autocatalysts in the enantioselective addition of diisopropylzinc to the corresponding aldehydes, such as pyrimidine-5-carbaldehyde. 2-Alkynyl-5-pyrimidyl alkanol with an enantiomeric excess (ee) of >99.5% automultiplies practically perfectly as an asymmetric autocatalyst in a yield of >99% and >99.5% ee. Asymmetric autocatalysis with an amplification of ee has thus been realized. Consecutive asymmetric autocatalysis starting with chiral 2-alkynylpyrimidyl alkanol of only 0.6% ee amplifies its ee significantly, and yields itself as the product with >99.5% ee. The reaction of pyrimidine-5-carbaldehyde and diisopropylzinc in the presence of chiral initiators with low ee's, such as secondary alcohol, amine, carboxylic acid, mono-substituted [2.2]paracyclophane, and chiral primary alcohols due to deuterium substitution, regulates the absolute configuration of the resulting pyrimidyl alkanols, and the ee of the resulting pyrimidyl alkanol is much higher than that of the chiral initiator. Leucine and [6]helicene with very low ee's, which are known to be induced by circularly polarized light (CPL), also serve as chiral initiators to produce pyrimidyl alkanol with higher ee's. Overall, the process represents the first correlation between the chirality of CPL and an organic compound with very high ee. Chiral inorganic crystals, such as quartz and sodium chlorate, act as chiral inducers in the asymmetric autocatalysis of pyrimidyl alkanol. The process correlates for the first time ever the chirality of inorganic crystals with an organic compound with very high ee.

Aldehydes↗
PubMed2001

Neuroendocrine small cell carcinoma of the uterine cervix showing polypoid growth and complicated by pregnancy.

BACKGROUND: Neuroendocrine small cell carcinoma of the uterine cervix is an aggressive disease, and it rarely is complicated by pregnancy. CASE: A polypoid tumor was found in the uterine cervix in a 27-year-old Japanese woman at 27 weeks of gestation. No polyp had been detected at 14 weeks of gestation. The polyp was excised and diagnosed as neuroendocrine small cell carcinoma by histological examination, including Grimelius, neuron-specific enolase, and chromogranin staining. A healthy infant was born by cesarean section at 29 weeks of gestation: this was followed by radical hysterectomy with pelvic lymphadenectomy. After surgery, four cycles of combination chemotherapy with cisplatin and etoposide were administered, and the patient is disease-free as of 13 months after surgery. CONCLUSION: When a polypoid lesion is found, especially when it demonstrates rapid growth, it may be necessary to excise and histologically examine the polyp even during pregnancy.

Adult↗
PubMed2001

Pelvic floor disturbance after childbirth: vaginal delivery damages the upper levels of sphincter innervation.

PURPOSE: Vaginal delivery disturbs pelvic floor innervation, which has previously been studied as a single mechanism. The effects of childbirth on innervation at different levels of the anal sphincter system were studied after childbirth. METHODS: Both anal manometry and motor latencies were measured in 67 females. Twenty-nine females (30.8 +/- 4.4 years) were examined four days after vaginal delivery. Eleven of these 29 females were re-examined five months after vaginal delivery. Nineteen females (33.6 +/- 4.6 years) who were examined five to nine days after undergoing an elective cesarean section and 19 asymptomatic, nonpregnant females (26.8 +/- 6.9 years) served as controls. Motor latencies were bilaterally measured within the anal sphincter system at 5, 3.8, 2.6, and 1.5 cm from the perineal skin by using a concentric needle electrode after sacral magnetic stimulation. Means of the bilateral latencies were analyzed. RESULTS: In postpartum females who gave birth vaginally, motor latencies at 5 and 3.8 cm, although not those at 2.6 and 1.5 cm, from the perineal skin were significantly prolonged, and anal pressure monitored by maximum resting and squeeze pressures was significantly decreased compared with that in control females. The decreased anal pressure normalized spontaneously. The prolonged motor latencies at the upper two levels of the anal sphincter system persisted in these females for five months after vaginal delivery. CONCLUSIONS: The disturbance of innervation of the upper anal sphincter system after vaginal delivery may last for a long time, whereas the decreased anal pressure normalizes in a short time. The protracted disturbance of innervation of the upper anal sphincter system may be associated with later development of fecal incontinence.

Adult↗
PubMed2001

Morphology of the mitochondria and endoplasmic reticula of chorion laeve cytotrophoblasts: their resemblance to villous syncytiotrophoblasts rather than villous cytotrophoblasts.

We examined the morphological features of the mitochondria and endoplasmic reticula of chorion laeve cytotrophoblasts from term human fetal membranes, and compared them with those of syncytiotrophoblasts and cytotrophoblasts from human placental villi. Ultrastructural enzyme histochemistry of cytochrome c oxidase and glucose-6-phosphatase were used as cytochemical markers for these intracellular organelles. Chorion laeve cytotrophoblasts possessed abundant endoplasmic reticula, and small mitochondria with a few cristae, which were characteristic of villous syncytiotrophoblasts rather than villous cytotrophoblasts. As for these organellar structures, statistical analysis confirmed similarities between chorion laeve cytotrophoblasts and villous syncytiotrophoblasts, but significant differences between laeve cytotrophoblasts and villous cytotrophoblasts. Though these two cytotrophoblasts originated from one common cell in early placental development, they exhibited quite different organellar morphology during placental/chorioamniotic differentiation. Considering previous data, we concluded that chorion laeve cytotrophoblasts were metabolically active cells, similar to villous syncytiotrophoblasts, performing many functions in fetal membrane physiology.

Biomarkers↗
PubMed2001

Enzyme histochemically detectable NAD(P)H oxidase in human placental trophoblasts: normal, preeclamptic, and fetal growth restriction-complicated pregnancy.

The purpose of the present study was to determine the subcellular localization of NAD(P)H oxidase, a reactive oxygen species (ROS)-producing enzyme, in the human placenta at various gestational ages. Ultrastructural enzyme histochemistry for NAD(P)H oxidase, using cerium as a capturing agent, was carried out. Placentas from patients with severe preeclampsia and patients who delivered infants with fetal growth restriction (FGR) were also studied. Electron-dense precipitates indicating NAD(P)H oxidase activity were visible in the microvillous membranes of the placentas, especially on the surface plasma membrane of the syncytiotrophoblast microvilli, after 25 weeks of gestation. The distribution pattern and enzyme intensities were apparently the same among normal, preeclamptic, and FGR placentas. Cytochemical control experiments ensured the specific detection of NAD(P)H oxidase activity. These observations indicated that syncytiotrophoblasts possessed NAD(P)H oxidase activity, and thus ROS-generating activity. Placental NAD(P)H oxidase may play a role in placental lipid peroxidation and the placental defense mechanism.

Cell Membrane↗
PubMed2001

Activation and localization of cartilage-derived morphogenetic protein-1 at the site of ossification of the ligamentum flavum.

Localization and expression of cartilage-derived morphogenetic protein (CDMP)-1 in tissues at the site of ossification of the ligamentum flavum (OLF) were examined by immunohistochemistry and in situ hybridization. The CDMP-1 protein and messenger ribonucleic acid (mRNA) were localized in spindle-shaped cells and chondrocytes in the OLF tissues. CDMP-1 was not detected in cells in non-ossified sites. These data indicate that CDMP-1 is locally activated and localized in spindle-shaped cells and chondrocytes at the site of OLE. Given the previously reported promoting action of CDMP-1 for chondrogenesis, the current results suggest that CDMP-1 may be involved in the progression of OLF, leading to the narrowing of spinal canal and thus causing severe clinical manifestations.

Aged↗