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K Saijoh

Publications and source records attributed to K Saijoh.

At least 19 recordsLinked to original sources
PubMed1998

Differential expression of nitric oxide synthase isoforms in form-deprived chick eyes.

PURPOSE: To clarify whether nitric oxide synthase (NOS) is involved in development of myopia, we examined the influence of form deprivation on the expressions of NOS isoform mRNA. METHODS: NOS isoform cDNAs were amplified from total RNA extracted from control and 7-day-form-deprived chick retina-RPE (retinal pigment epithelium)-choroid, using competitive RT-PCR (reverse-transcription polymerase chain reaction). Each NOS isoform protein was also analyzed by Western blotting and immunohistochemistry. RESULT: Expression of inducible NOS (iNOS) mRNA was highest in the control chick retina-RPE-choroid, followed by the expression of brain NOS (bNOS) mRNA. Expression of endothelial NOS (eNOS) mRNA was faint. The iNOS protein level, however, was only slightly higher than the levels of the bNOS and eNOS proteins and was found mainly in the outer part of the photoreceptor layer and inner and outer parts of RPE and choroid. bNOS alone was found in the outer nuclear layer. Although form deprivation reduced the iNOS and bNOS mRNA expressions, only the iNOS protein showed significant reduction. CONCLUSION: All three NOS isoforms were expressed in chick retina-RPE-choroid. Predominant expression of iNOS, instead of bNOS and eNOS, suggested the existence of ocular tissue-specific regulation of the iNOS gene. In addition to differences in expression level, bNOS displayed regional differential expression. Moreover, only iNOS was reduced in response to form deprivation. It is suggested that NOS isoforms may be differentially involved in the mechanisms regulating the posterior eye tissues, including myopic eye growth.

Animals↗
PubMed1997

Analysis of bovine selenoprotein P-like protein gene and availability of metal responsive element (MRE) located in its promoter.

Selenoprotein P-like protein, similar to selenoprotein P, uses multiple TGAs for incorporation of selenocysteines but not as stop codons. It is also characterized by having a His-Pro-rich domain and a regionally differential expression pattern. Hence, in addition to selenium metabolism, this protein is considered to have a developmental function. In the present study, the structure of the selenoprotein P-like protein gene was analyzed. The gene consisted of five exons, and the 5'-flanking region contained a TATA box, TCF-1-CS, bHLH-CS, gamma-IRE-CS, c-Myb-CS, C/EBP-CS, HNF-5-CS, MRE2-CS, etc. The presence of motifs like TCF-1-CS, c-Myb-CS, etc. supports the suggestion that this protein is involved in cellular maturation. Since the presence of MRE2-CS suggests that this protein is related to the antidote effect of selenium against heavy metal intoxication, the availability of this motif was examined using bovine kidney cell lines, CKT-1 and MDBK. Metallothionein mRNA markedly increased 6 h after administration of 10(-6) M CdCl2 and ZnCl2 in both cell lines. No significant alteration was observed in selenoprotein P-like protein mRNA, whereas its basal expression was high, indicating that this protein is constitutively expressed. Thus, it is still possible that this protein acts as an antidote, even though it is not inducible by heavy metals.

Animals↗
PubMed1997

Cloning of mouse diastrophic dysplasia sulfate transporter gene induced during osteoblast differentiation by bone morphogenetic protein-2.

Although intensive studies have been directed at understanding osteoblastic differentiation, the molecular mechanisms are still unclear. In this study, we describe a cDNA that encodes a sulfate transporter that was cloned as a gene induced in osteoblast precursor cells in association with osteoblastic differentiation. Based on the fact that bone morphogenetic protein-2 (BMP-2) induces osteoblastic phenotypes in immature mouse fibroblastic C3H10T1/2 cells, we performed a subtraction hybridization between BMP-2-treated and untreated cells, and have isolated one clone (designated as st-ob for sulfate transporter in osteoblast) induced by BMP-2 that is constantly expressed in osteoblastic cells. The deduced amino acid sequence and proposed structure of st-ob are mostly identical to those of the human diastrophic dysplasia sulfate transporter gene product (DTDST). St-ob mRNA was abundantly expressed in the thymus, testis, calvaria and osteoblastic MC3T3-E1 cells, whereas its expression was faint in C3H10T1/2 cells. Expression of st-ob in C3H10T1/2 cells was increased by transforming growth factor-beta1 (TGF-beta1), retinoic acid and dexamethasone as well as BMP-2. Furthermore, BMP-2 increased sulfate incorporation in C3H10T1/2 cells about twice as high as the baseline level. Osteoblasts actively take up sulfate to synthesize proteoglycans, which are one of the major components of the extracellular matrix of bone and cartilage. The present study demonstrates that st-ob induced during osteoblastic differentiation is an important phenotype of osteoblasts for characterizing their function.

Animals↗
PubMed1997

Cloning and characterization of the 5'-flanking region of the mouse diastrophic dysplasia sulfate transporter gene.

Dyastrophic dysplasia sulfate transporter (DTDST) plays an important role in proteoglycan synthesis in the extracellular matrix of bone and cartilage. Recently, we found that the mouse DTDST gene was induced in pluripotent C3H10T1/2 cells during differentiation by bone morphogenetic protein-2 (BMP-2). To clarify the transcriptional regulation of the DTDST gene, we have cloned the 5'-flanking region of the mouse DTDST gene by the PCR based gene walking method. Sequence analysis revealed the presence of the TATA box followed by GC rich sequences containing two Sp-1 binding sites and a CBFA1 binding site. Transient transfection assays demonstrated that the basal transcriptional activity in osteoblastic MC3T3-E1 cells was mainly present between -309 and -275 bp upstream of the transcription start site (Segment -309/-275) which contained the consensus sequence for the xenobiotic-responsible element (XRE). Nuclear proteins from MC3T3-E1 cells and C3H10T1/2 cells could bind to this short segment in vitro. BMP-2 increased the promoter activity as well as the nuclear protein binding to the sequence in C3H10T1/2 cells. The present data suggest that the DTDST gene expression in osteoblasts and differentiating precursor cells to osteoblast/chondrocyte lineage would be mainly regulated by undetermined XRE binding transcription factors.

Animals↗
PubMed1997

Endogenous adenosine facilitates neurotransmission via A2A adenosine receptors in the rat superior colliculus in vivo.

The concentration of endogenous adenosine in the cerebrospinal fluid increased 2-3-fold of the original level in the area of rat superior colliculus after the intraperitoneal administration of an adenosine deaminase inhibitor, EHNA (erythro-9-(2-hydroxy-3-nonyl)adenosine, 10 mg/kg). Potentials evoked in the superior colliculus by optic tract stimulation were also facilitated by 120-160% of their initial amplitudes. A selective A1 adenosine receptor antagonist, DPCPX (8-cyclopentyl-1,3-dipropylxanthine), failed to reduce such EHNA-induced facilitation. However, a selective A2A adenosine receptor antagonist, KF17837 (8(3,4-dimethoxystyryl)-1,3-dipropyl-7-methylxanthine) completely eliminated the facilitatory effects of EHNA. Northern blot analysis demonstrated abundant expression of A1 adenosine receptor mRNA in the superior colliculus. RT-PCR analysis was able to detect the concomitant expression of A2A adenosine receptor mRNA, but at levels lower than one-tenth of the striatal expression. In the superior colliculus, A2A adenosine receptors function predominantly on the facilitatory effects of adenosine, irrespective of the ubiquitous expression of A1 adenosine receptors.

Adenine↗
PubMed1997

Relationship of anesthetic activity of alkyl acetates to hydrophobicity and in vivo effect on membrane fluidity in mice.

In vivo anesthetic activity of alkyl acetates in mice was studied in relation to hydrophobicity and the in vivo effect on membrane fluidity. The anesthetic potency (AD50) of alkyl acetates was determined; AD50 shows the i.p. dose required to anesthetize 50% of mice from the treated group. We used log P (n-octanol/water partition coefficient) as an operational definition of hydrophobicity. Membrane fluidity was determined using 1,6-diphenyl-1,3,5-hexatriene (DPH) as fluorescence probe. Log (1/AD50) was a parabolic function of log P, and the value of log P that corresponds to the minimum AD50 was estimated to be 2.08. Brain synaptosomal membranes were prepared from mice 30 min after dosing with each of the three alkyl acetates applied at 1.5-fold AD50: n-butyl, n-amyl, and n-hexyl acetate. In each alkyl acetate group, most of the animals were anesthetized (> 68%). Decreased membrane fluidity was observed for the animals that were anesthetized while no change in the fluidity was seen for the animals that were not anesthetized. The results suggest an involvement of decreased DPH fluidity in alkyl acetate-induced anesthesia.

Acetates↗
PubMed1997

Human papillomavirus infection and risk determinants for squamous intraepithelial lesion and cervical cancer in Japan.

A case control design was used to investigate human papillomavirus (HPV) prevalence and risk factors associated with development of cervical squamous intraepithelial lesion (SIL) and cervical cancer (CC) in Japan. One hundred and twenty-three women with histologically confirmed SIL or CC were compared to a control group of 778 cytologically normal women. With the use of a polymerase chain reaction (PCR)-based method for detection of low-risk (types 6 and 11) and high-risk (types 16, 18, 31, 33, 35, 52 and 58) HPVs, a high prevalence of HPV infection was observed in smokers among the controls. Logistic regression analysis demonstrated that high-risk HPV infection was the most significant risk determinant for LSIL (OR=9.4, 95% CI=4.5-19), HSIL (OR=77, 95% CI=28-217) and CC (OR=97, 95% CI=35-269). It also showed that unmarried women, women married for 5 to 19 years and smokers represented high risk groups for SIL, while smokers and women with a history of many pregnancies/parities had increased risk for CC. Smoking was the only HPV infection-independent factor for CC, suggesting that smoking may have a carcinogenic effect on the cervix. Since neither history of other cancer nor family cancer history was associated with SIL or CC, genetic factors appear to play little role in cervical carcinogenesis. The risk for cervical neoplasia due to HPV infection increased after marriage in Japan, suggesting a role for husbands as carriers of HPV transmission. Protection from high-risk HPV infection may be of greatest importance for prevention of cervical cancer.

Adolescent↗
PubMed1997

Regulation of selenoprotein P mRNA expression in comparison with metallothionein and osteonectin mRNAs following cadmium and dexamethasone administration.

Selenium is recognized as an essential trace element and an antidote for carcinogens, heavy metals etc., and also as an environmental pollutant causing dysfunction of both the brain and peripheral tissues. Selenoprotein P (SelP) contains 10 selenium per molecule in the form of selenocysteines. To clarify whether SelP involved in selenium requirement and toxicity, SelP mRNA expression was compared with the expression of metallothionein (MT) and osteonectin (OST) mRNAs, the protein products of which are known to have antidote effects. MT and OST are induced by diverse forms of stress and immediately affect genes with stress promoter sequences. Cd and dexamethasone were used to examine such secondary regulation. Basal expression of SelP mRNA was high both in NRK cells and in rat kidney and brain but dexamethasone induction was observed only in NRK cells. Dexamethasone, but not Cd, decreased expression of OST mRNA in NRK cells, while OST mRNA in the kidney and brain increased after Cd administration in rats. Induction of MT mRNA was observed in response to Cd and dexamethasone in all cells and tissues examined, while the net increase was little because its basal expression was faint. Moreover, in situ hybridization indicated that SelP mRNA expression was localized to the cerebellum, one of the targets of selenium toxicity. The cerebellum is also a target for methyl-Hg intoxication, symptoms of which are ameliorated by selenium. Thus, SelP seems to be involved in both selenium homeostasis and detoxication mechanisms even though SelP mRNA is not always inducible.

Animals↗
PubMed1996

Expression ratio of hepatocyte nuclear factor-1 to variant hepatocyte nuclear factor-1 in differentiation of hepatocellular carcinoma and hepatoblastoma.

BACKGROUND/AIMS: Liver-specific protein genes have multiple cis-/trans-acting elements, but those accountable for hepatocytic differentiation are unclear. An AT-rich core sequence (AT motif) is essential as a cis-acting element for the hepatic transcription. Homologous proteins hepatocyte nuclear factor-1 (HNF-1) and variant HNF-1 (vHNF-1) bind to this motif. The ratio of HNF-1 to vHNF-1 mRNA was examined in various liver tissues with respect to their differentiation. METHODS: The competitive reverse transcriptional polymerase chain reaction was employed to amplify HNF-1 and vHNF-1 mRNA simultaneously and to examine their expression ratio in total RNA extracted from frozen liver tissues of 37 patients with hepatocellular carcinoma, five patients with hepatoblastoma, and 15 non-neoplastic liver tissues. RESULTS: The ratio of HNF-1 to vHNF-1 mRNA was higher in well-differentiated cases than in poorly-differentiated and undifferentiated cases, except that one poorly-differentiated hepatoblastoma displayed a high ratio. Non-neoplastic liver tissues had low ratios similar to poorly-differentiated hepatocellular carcinoma, the reason for which remained unknown. However, chronic hepatitis and liver cirrhosis cases also demonstrated low ratios, and hence degenerative changes themselves displayed no obvious influence on such ratios. Thus, the gene expression of HNF-1 and vHNF-1 seemed to be differentially regulated in neoplastic and non-neoplastic hepatocytes. CONCLUSIONS: These results suggested that the ratio of HNF-1 to vHNF-1 mRNA correlated with histological differentiation of HCC and hepatoblastoma.

Adult↗
PubMed1995

Regional differences in expression of osteonectin mRNA after administration of cadmium to rats.

Osteonectin gene expression in relation to metallothionein mRNA expression was investigated in various tissues from Cd-treated rats. After a single 50 micromol/kg subcutaneous injection of CdCl2, Cd predominantly accumulated in the liver and metallothionein gene expression significantly increased concomitantly with Cd accumulation, but no alteration of osteonectin gene expression was observed. In the kidney and lung, both metallothionein and osteonectin mRNA increased significantly but the elevation of metallothionein mRNA levels (1 h after Cd administration) preceded that of osteonectin (3 h after administration). A significant elevation of osteonectin mRNA levels was also observed in the testis after 3 h, but that of metallothionein mRNA occurred after 6 h. Not only accumulation of Cd but also increments in both osteonectin and metallothionein mRNA were minimal in the brain, but a significant increase in gene expression was observed after 1 h for osteonectin and after 3 h for metallothionein. Since, except in the testis, metallothionein gene expression preceded osteonectin gene expression, the induced metallothionein might transpose Cd and thereby affect its levels immediately, thus reducing the levels of Cd available for accumulation in other tissues. Hence, the osteonectin-Cd interaction might be secondary to the metallothionein-Cd interaction. However, the fact that osteonectin mRNA was predominantly induced by Cd administration in the target tissues of Cd toxicity, such as the lung, kidney and testis, suggests the possible involvement of osteonectin in Cd intoxication/detoxication mechanisms.

Amino Acid Sequence↗
PubMed1995

Molecular cloning of cDNA encoding a bovine selenoprotein P-like protein containing 12 selenocysteines and a (His-Pro) rich domain insertion, and its regional expression.

When cDNA containing proteins enriched in the bovine cerebellar cortex were cloned, a clone which seemed to encode a selenoprotein P-like protein was isolated. The coding nucleotide sequence of its cDNA insert displayed high homology to rat and human selenoprotein P cDNA but contained 12 rather than 10 TGAs (12 rather than 10 selenocysteines in deduced amino acids), a tandem repeat of one CACTCC (His-Ser) and seven CATCCCs (His-Pro), and a 3' untranslated region approximately 890 bases shorter than that of rat liver selenoprotein P. RT-PCR using a set of primers flanking to the repeat displayed the existence of mRNA without the repeat. The tandem repeat and its adjacent region consisted of a similar motif of CAC/TCC/AC/T. Thus, these proteins included a (His-Pro) rich domain with a slightly negative free energy change irrespective of having the tandem repeat or not. Such His-Pro repeats reportedly exist in the segmentation gene paired or homeobox protein Om(1D) of Drosophila. Moreover, both this selenoprotein P-like protein mRNA and selenoprotein P mRNA were expressed in all the areas of the brain but most prominently in the cerebellar cortex, hippocampus, and olfactory bulb. These findings suggest the possibility that these selenoproteins are major selenium carriers in the brain and play a role in the morphological response of nerve or glial cells.

Amino Acid Sequence↗
PubMed1995

[Serotonin].

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Humans↗
PubMed1994

Calcitonin directly acts on mouse osteoblastic MC3T3-E1 cells to stimulate mRNA expression of c-fos, insulin-like growth factor-1 and osteoblastic phenotypes (type 1 collagen and osteocalcin).

The present study was performed to examine whether calcitonin directly acted on mouse osteoblastic MC3T3-E1 cells to stimulate the mRNA expression of insulin-like growth factor-1 (IGF-1) and c-fos, followed by an increase in their proliferation and differentiation. Eel calcitonin increased [3H]thymidine incorporation and alkaline phosphatase activity as well as the mRNA expression of type 1 collagen and osteocalcin which were characteristic of osteoblasts. Eel calcitonin (10(-8)M) induced c-fos mRNA transiently after its addition, followed by gene expression of IGF-1, an important autocrine/paracrine growth factor in the regulation of osteoblastic proliferation. We first demonstrated that calcitonin directly acted on osteoblasts to stimulate transcription of c-fos and IGF-1 genes as well as functional phenotypes including type 1 collagen and osteocalcin.

Animals↗
PubMed1993

Effects of methylmercury on protein kinase A and protein kinase C in the mouse brain.

The effects of methylmercury administration on adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (protein kinase A) and protein kinase C were investigated by determining their second messenger bindings ([3H]cAMP binding for protein kinase A and [3H]PDBu for protein kinase C) and enzymatic activities in the brains of methylmercury-treated mice. After single administrations of methylmercury (10 mgHg/kg, sc), no neurological symptoms were observed, while the mercury concentration in the brain reached 5.6 ppm. Neither second messenger bindings nor enzymatic activities of either protein kinase displayed significant changes. When methylmercury was administered repeatedly (10 mg Hg/kg x 5), the mercury concentration was 11.7 ppm and the enzymatic activity of protein kinase C was reduced to 75% of the control level without significant change in [3H]PDBu binding. Significant change has not been observed in either [3H]cAMP binding or enzymatic activity of protein kinase A. The reduction of enzymatic activity of protein kinase C was reversed by the simultaneous administration of selenite (0.5 mgSe/kg x 5). However, the fact that selenite administration alone displayed not a significant but about a 20% increase in [3H]PDBu binding suggested that selenite itself could affect the level of protein kinase C despite having no apparent effects on protein kinase C in vitro. Further investigation is necessary to assess whether protein kinase C is involved in the detoxication mechanism of selenite with respect to methylmercury. Since the mercury concentration in the brain was higher than the IC50s for both protein kinase A and protein kinase C observed in vitro even after single administration, methylmercury might inhibit both protein kinases, which might impair intracellular signal transduction. This might in part conceal the symptoms during the early stages of methylmercury toxicity.

Animals↗
PubMed1991

Recent status of the medical examiner system in Japan: demographic variation of medicolegal deaths in Hyogo Prefecture and uncertainty in medicolegal investigations conducted by medical practitioners.

The medical examiner system has been steadily abolished in Japan. Instead, medicolegal investigations are entrusted by the police to medical practitioners, who are not permitted to perform autopsies. The necessity for the medical examiner system was assessed through inquest records in Hyogo, one of the three prefectures which still have medical examiner systems. Standardized mortality ratios (SMRs) for accidents and suicides were negatively associated with population density, being high in rural areas with a large proportion of elderly citizens, while the SMR for natural deaths was high in urbanized areas and associated with the proportion of inquests to total resident deaths. The high proportion of inquests, however, did not always mean that inquest records were of good quality. Significant differences in the quality of medicolegal investigations seemed to exist between medical examiners and medical practitioners. That is, in order to certify the cause-of-death, medical examiners performed autopsies in about half of their cases, while only 2% of medical practitioner cases were subjected to autopsies. Medical practitioners, who certified the cause-of-death as "heart failure" without advising an autopsy, were regularly entrusted with inquests. It is likely that the causes-of-death for medicolegal cases may be questionable since more than 85% of all medicolegal deaths were investigated by medical practitioners, which may cause inaccuracy in at least 3-7% of mortality statistics. It is necessary to educate medical practitioners concerning the importance of mortality statistics and ICD and on the validity of autopsies, in order to obtain accurate mortality statistics from medicolegal cases.

Accidents↗
PubMed1991

Action of mercurials on 3H-cAMP binding to the regulatory subunit-II of cAMP-dependent protein kinase.

Binding of the regulatory subunit type II (RII) of adenosine 3',5'-cyclic monophosphate (cAMP) dependent protein kinase was inhibited by Hg2+ with an IC50 value of 0.31 microM. Methyl mercury, p-chloromercuribenzoic acid (PCMB), and 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) also inhibited cAMP binding with IC50 values of 70-80 microM for organic mercurials and 130 microM for DTNB. Addition of 1 mM 2-mercaptoethanol and 1 M cysteine to the assay mixture reversed these inhibitions. N-ethylmaleimide (NEM) showed little effect on the binding. On the other hand, Hg2+ and methyl mercury markedly suppressed enzymatic activity of the catalytic subunit. The IC50 value was 0.13 microM for Hg2+ and 0.15 microM for organic mercurials. Scatchard plots of kinetic analysis data for the cAMP binding revealed a noncompetitive type of inhibition by mercurials and DTNB. It is suggested that blockade of sulfhydryl groups resulted in the inhibition of cAMP binding to the RII subunit, which might result in preserving the association of the RII subunit and the catalytic subunits and in preventing further inactivation of the catalytic subunit by Hg2+.

Animals↗
PubMed1991

Mortality in medicolegal deaths in Hyogo Prefecture (1986-88).

Only three medical examiner offices are undertaking inquests on medicolegal deaths and no coroner system exists in Japan. Medical practitioners are also entrusted to hold such inquests. Certificates filed by the medical examiners of Hyogo Prefecture were compared with those filed by medical practitioners. Medical examiners certified deaths as "heart failure" only when no pathological changes were found after an autopsy. Of 2,622 deaths caused by diseases, 1,707 were certified as "heart failure" by medical practitioners without performing an autopsy. The term "heart failure" seems likely to be misused for deaths of which causes are unknown. Although the age-adjusted mortality rate for "heart disease" in Japan (98.7 per 100,000 population) showed a higher rate than for "cerebrovascular disease" (84.2), it included 53.9 for "heart failure". The misuse of the term "heart failure" seems to have introduced serious bias into the recent mortality statistics of Japan. This inaccuracy is due to ignorance about the importance of mortality statistics and ICD. Improvement in the reliability of mortality statistics is necessary for disease prevention projects through clinical medicine and public health means.

Cause of Death↗