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Biomedical subjects

N Sakuragawa

Publications and source records attributed to N Sakuragawa.

At least 19 recordsLinked to original sources
PubMed1999

Gene expression of oligodendrocyte markers in human amniotic epithelial cells using neural cell-type-specific expression system.

We have previously reported that human amniotic epithelial (HAE) cells expressed neuronal and glial cell markers using immunostaining and western blotting. To study the expression system of these cell markers in HAE cells, we investigated the expression of mRNA for oligodendrocyte markers in HAE cells by reverse-transcriptase-polymerase chain reaction (RT-PCR) and northern blotting. Neural cell-specific expression system was used to examine the transcriptional activity of myelin basic protein (MBP). Oligodendrocyte markers were expressed such as CNPase, MBP and proteolipid protein (PLP and DM-20). PLP gene transcripts in the cells were in a lower level than DM-20, compared with those of human brain. Neural cell-type-specific expression system disclosed HAE cells were about 20% positive for beta-Gal using AdexMBP-NL-LacZ. This strongly indicates that HAE cells have MBP-specific gene expressing cells.

Animals↗
PubMed1999

Detection of dopamine D2 receptor mRNA and binding sites in monkey amniotic epithelial cells.

Previous results from our laboratory showed that monkey amniotic epithelial cells (MAEC) possess the catecholamine synthesizing enzymes and have the capacity to synthesize and release CA. Recently, we also reported that these cells express dopamine D1 receptor mRNA and binding sites. This study was designed to investigate the presence of dopamine D2 receptors in MAEC. Using RT-PCR, we found that MAEC express dopamine D2 receptor mRNA that is having 98% homology with human dopamine D2 receptors. Radioligand saturation binding studies showed a 3H-YM-09151-2 high-affinity binding site with a K(D) of 0.293+/-0.06 nM and Bmax of 180.69+/-11.61 fmol/mg protein. Competition experiments with a variety of displacing drugs demonstrated that D2 antagonists potently compete with 3H-YM-09151-2 binding, whereas D1 antagonists displayed a weaker competition for the binding sites. The rank order of potency of these compounds in competing with 3H-YM-09151-2 for binding sites was consistent with the pharmacology of the dopamine D2 receptors. All competition curves were better fitted to a one-site model with a Hill coefficient around unity, indicating that 3H-YM-09151-2 is labeling a single population of receptors. These results provide, for the first time, a compelling evidence that MAEC natively express dopamine D2 receptor mRNA and binding sites, and they suggest that monkey amniotic epithelial cells (MAEC) could represent a source of primate dopamine receptors without the need for transformation or cloning procedures using nonprimate cells, as generally happens.

Amnion↗
PubMed1999

Evidence for the presence of dopamine D1 receptor mRNA and binding sites in monkey amniotic epithelial cells.

In this study we examined the presence of dopamine D1 receptors in monkey amniotic epithelial cells (MAEC) using RT-PCR and radioligand binding experiments. We found that MAEC express D1 receptor mRNA that is having 99% homology with human dopamine D1 receptors. Saturation binding studies using [3H]SCH-23390 showed a high affinity D1 site with K(D) and Bmax values of 0.82 +/- 0.12 nM and 20.77 +/- 4.22 fmol/mg protein, respectively. Competition experiments showed that selective D1, but not D2, antagonists are potent displacers of [3H]SCH 23390 binding with a rank order of potency that is consistent with the pharmacology of the dopaminergic D1 site. These data provide, for the first time, compelling evidence that MAEC natively express D1 mRNA and binding sites and suggest that it may be a potential primate cell model to study D1 receptors and to explore new selective drugs active at these receptors.

Amnion↗
PubMed1999

Hemostatic molecular markers before the onset of disseminated intravascular coagulation.

We retrospectively measured various hemostatic markers in 240 patients with disseminated intravascular coagulation (DIC) before the onset of DIC and in 110 non-DIC patients, and examined their usefulness for the diagnosis of pre-DIC. Changes in prothrombin time ratio and fibrinogen levels were not significant before the onset of DIC. The plasma levels of fibrinogen and fibrin degradation products before the onset of DIC were increased and the platelet count was gradually reduced in nonleukemic patients; these changes were already significant in the non-DIC state. The plasma levels of thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex (PPIC), D-dimer, and soluble fibrin monomer (sFM) were increased before the onset of DIC. In leukemic patients, the plasma levels of sFM on day 5, those of TAT on day 3, and D-dimer on day 1, were significantly increased before the onset of DIC. The levels of most hemostatic markers 7 days before the onset of DIC were not different from those observed in the non-DIC state. In nonleukemic patients, only D-dimer, sFM, and TAT levels were significantly increased 7 days before the onset of DIC compared with values in the non-DIC state. The positive rate of hemostatic markers for the diagnosis of DIC, TAT, and PPIC were high during the pre-DIC and non-DIC groups. The plasma levels of sFM and D-dimer were low in non-DIC and increased gradually during the pre-DIC state. These findings suggest that hemostatic molecular markers such as sFM, D-dimer, and TAT are useful for the diagnosis of pre-DIC, although their cutoff values were different among various diseases.

Antifibrinolytic Agents↗
PubMed1999

Possible dynamic neurotransmitter metabolism surrounding the fetus.

Human amniotic epithelial cells express makers of glial and neural stem cells. These cells also synthesize and release acetylcholine and catecholamines. This study of amniotic fluid demonstrated that acetylcholine and catecholamines can be readily identified in the fluid. Norepinephrine was the major catecholamine present, although dopamine and DOPAC could also be detected. The physiologic role of these amniotic fluid neurotransmitters in fetal-placental interactions and nervous system development is currently under investigation.

Acetylcholine↗
PubMed1998

Adenovirus-mediated transfer of human acid maltase gene reduces glycogen accumulation in skeletal muscle of Japanese quail with acid maltase deficiency.

Acid maltase deficiency (AMD) causes a lysosomal glycogenosis inherited as an autosomal recessive trait. The infantile type of AMD (Pompe disease) leads to early death due to severe dysfunction of cardiac and respiratory muscles and no effective therapy is available. Replication-defective adenovirus vectors offer a promising tool for in vivo gene delivery and gene therapy. We constructed a recombinant adenovirus containing the human acid maltase (AM) cDNA downstream of the CAG promoter, composed of modified chicken beta-actin promoter and CMV IE enhancer (AxCANAM). Japanese quail with AMD was used for this study as an animal model for human AMD. When cultured fibroblasts from AMD quail were infected with AxCANAM, AM activity in the cells increased in proportion to the multiplicity of infection (MOI). When AxCANAM (4.5 x 10(8) PFU) was injected into unilateral superficial pectoral muscle of AMD quail, PAS staining showed that glycogenosomes disappeared and stainability of acid phosphatase was reduced in the injected area as compared with the contralateral muscle of the same birds. Biochemically, AM activity increased and glycogen content decreased in the injected muscle. Western blot analysis showed that AMD quail muscle injected with AxCANAM expressed human AM protein processed to active forms. These results suggest that the human AM cDNA transferred by an adenovirus vector was sufficiently expressed, leading to a marked reduction of the glycogen accumulation in the skeletal muscle of AMD quail.

Adenoviridae↗
PubMed1998

Synthesis and release of catecholamines by cultured monkey amniotic epithelial cells.

In this study, we investigated the presence, possible synthesis, and release of catecholamines (CA) by monkey amniotic epithelial cells (MAEC) using different methods. Immunocytochemical techniques demonstrated the presence of tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine-beta-hydroxylase (DBH), and dopamine (DA) immunoreactivities, suggesting the capability of these cells to synthesize CA. Further evidence from high performance liquid chromatography (HPLC) studies indicated the presence of norepinephrine (NE), DA, and its metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) in the cell extracts of cultured MAEC. Incubation of MAEC for various time intervals in medium supplemented with L-tyrosine and tetrahydrobiopterin significantly increased the production of CA, thus confirming active synthesis of CA by MAEC and that increasing the incubation time increases this synthesis. In contrast, pharmacological inhibition of TH by alpha-methyl-p-tyrosine significantly reduced CA production, further confirming CA synthesis by MAEC. Catecholamines were also detected in the cell incubation media, suggesting the ability of MAEC to spontaneously secrete CA. Moreover, depolarization with high concentration of K+ increased the amount of CA released into the incubation media. Additionally, the detection of DOPAC, a primary metabolite of DA, in MAEC strongly indicates that these cells contain DA metabolizing enzymes. These results demonstrate the presence of CA in MAEC and that these cells can synthesize and release CA. Further extensive studies are needed to fully explore MAEC so that it may serve as a model to study the aspects of catecholaminergic activity in primate cells and may be a possible candidate for allotransplantation therapy of monkey model of Parkinson's disease.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1998

A case of alternating hemiplegia of childhood with cerebellar atrophy.

A case of alternating hemiplegia of childhood is reported. Tonic fits and generalized tonic-clonic seizures developed during her infancy. Frequent twitching and apneic seizures appeared at 16 years of age. Zonisamide transiently suppressed the tonic, twitching and apneic seizures, as well as the facial and neck dystonia. Cranial computed tomography and magnetic resonance imaging revealed progressive vermian atrophy. Cerebellar dysfunction may play a role in the clinical features of some patients with alternating hemiplegia of childhood.

Adolescent↗
PubMed1998

Factor VII Morioka (FVII L-26P): a homozygous missense mutation in the signal sequence identified in a patient with factor VII deficiency.

We investigated the molecular basis of factor VII deficiency in a Japanese patient and identified a novel missense mutation in the signal sequence of the gene. Factor VII activity and antigen level measured in the patient were 10.7% and 11% of normal, respectively. All exons except 1B and the 5'-flanking region containing promoter region were amplified by polymerase chain reaction (PCR) from genomic DNA. Sequencing analysis of the PCR fragments revealed that the patient was a homozygote for a T to C substitution at nucleotide position 38. This mutation predicts an amino acid replacement of leucine to proline at codon -26 in the hydrophobic core of the signal peptide, which probably affects translocation of the protein into endoplasmic reticulum and subsequently causes reduction in plasma factor VII level.

Aged↗
PubMed1998

Genetic analysis of mutations in seven Japanese families with type I antithrombin deficiency.

We have performed genetic analysis on seven Japanese families with type I antithrombin (AT) deficiency by the polymerase chain reaction (PCR)/direct DNA sequencing method. Five distinct mutations including two novel ones were identified in six of seven families. All subjects investigated were heterozygous for the mutations. In one family, however, no genetic abnormality was found within the analyzed DNA sequences. The identified mutations were as follows: (1) a T-to-C substitution at nucleotide position 2747, which predicts an amino acid replacement of Cys (TGT) 95 by Arg, was found in two families; (2) a 4-bp deletion (-TTTC) at nucleotide position 2647-2650, which causes frameshift and a premature stop codon at codon 80; (3) a 3-bp deletion (-CTT) within nucleotide position 5356-64, which causes deletion of a Phe at amino acid numbers 121-123; (4) a C-to-T substitution at nucleotide 5381, which induces a replacement of Arg (CGA)129 by a stop codon (TGA); (5) a C-to-T substitution at nucleotide number 2745, which causes an amino acid replacement of Ala (GCC) 94 by Val (GTC). Our results confirm that the genetic background and molecular pathogenesis of type I AT deficiency is highly heterogeneous.

Adult↗
PubMed1998

Hemostatic molecular markers before onset of disseminated intravascular coagulation in leukemic patients.

The changes in various hemostatic parameters were examined within a period from 7 days before the onset of disseminated intravascular coagulation (DIC) in 114 patients (i.e. in their pre-DIC state). The changes in prothrombin time (PT) ratio and fibrinogen levels were not significant before the onset of DIC. Plasma fibrinogen and fibrin degradation products (FDP) levels before the onset of DIC were high, but these changes were already significant in 110 non-DIC patients examined. Plasma thrombin-antithrombin complex (TAT), plasmin-plasmin inhibitor complex (PPIC), D-dimer and soluble fibrin monomer (SFM) levels were high before the onset of DIC. In the 110 leukemic DIC patients, the plasma SFM levels were significantly increased 5 days before, the plasma TAT levels were significantly increased 3 days before, and the D-dimer levels were significantly increased 1 day before the onset of DIC. The plasma tissue factor and plasminogen activator inhibitor-I levels were not significantly changed before the onset of DIC. The PT ratio, fibrinogen, FDP, platelet count, antithrombin, D-dimer, and PPIC levels at 7 days before the onset of DIC were not significantly different from the corresponding values in the non-DIC group, although the hemostatic molecular markers SFM, D-dimer, and TAT are useful for the diagnosis of pre-DIC. Plasma thrombomodulin levels were significantly increased in these patients who died, and plasma antithrombin and protein C activities markedly reduced in the patients who died. The outcome of the diseases underlying DIC is related to vascular endothelial cell injuries.

Biomarkers↗
PubMed1998

Transcriptional regulation of urokinase-type plasminogen activator receptor by cyclic AMP in PL-21 human myeloid leukemia cells: comparison with the regulation by phorbol myristate acetate.

We investigated the effect of dibutyryl cyclic AMP (Bt2-cAMP) on urokinase-type plasminogen activator receptor (uPAR) expression in human PL-21 myeloid leukemia cells and compared it with the effect of phorbol myristate acetate (PMA). Flow cytometric analysis clearly demonstrated that Bt2-cAMP and PMA both induced the cell surface expression of uPAR. Northern analysis and nuclear run-on assay revealed that cAMP and PMA activated the uPAR gene transcription and both additively increased the uPAR mRNA level. However, actinomycin-D decay experiment showed that PMA, but not cAMP, prolonged the uPAR mRNA half-life. Furthermore, inhibition of the ongoing protein synthesis with cycloheximide abrogated completely the PMA-induced uPAR mRNA accumulation but only partially the induction by PMA plus cAMP, whereas the induction by cAMP alone was rather amplified, indicating that the de novo protein synthesis is necessary in the induction by PMA but not in the induction by cAMP and that the cAMP pathway may be dominant in uPAR gene expression in the PL-21 cells as compared to the PMA pathway. These results suggest that cAMP induces the uPAR expression exclusively through activating the gene transcription in which a preexisting transcriptional factor may be involved, whereas PMA transcriptionally and posttranscriptionally regulates the uPAR gene expression.

Carcinogens↗