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J Arai

Publications and source records attributed to J Arai.

At least 37 records · Page 2Linked to original sources
PubMed2000

Contemplation of age-adjusted standard values of lipid profiles in Japan.

In order to establish the age-adjusted standard values of lipids in both sexes in Japan, we examined the plasma levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride levels in 1262 healthy Japanese subjects (male 616, female 646). LDL-cholesterol levels in women increased significantly in relation to menopause as it rises from 112 mg/dL in 40 year olds to 131.2 mg/dL in 50 year olds. Menopause seems to affect the triglyceride levels as well. These age- and sex-dependent changes should be considered in evaluation of patients' lipid profiles.

Adult↗
PubMed1999

Fas-independent cytotoxicity mediated by human CD4+ CTL directed against herpes simplex virus-infected cells.

The present study was undertaken to clarify the mechanisms of cytotoxicity mediated by virus-specific human CD4+ CTLs using the lymphocytes of family members with a Fas gene mutation. CD4+ CTL bulk lines and clones directed against HSV-infected cells were established from lymphocytes of a patient with a homozygous Fas gene mutation and of the patient's mother. HSV-specific CD4+ CTLs generated from lymphocytes of the patient and her mother exerted cytotoxicity against HSV-infected cells from the patient (Fas-/-) and from her mother (Fas+/-) to almost the same degree in an HLA class II-restricted manner. mRNAs for the major mediators of CTL cytotoxicity, Fas ligand, perforin, and granzyme B, were detected in these CD4+ CTLs using the RT-PCR and flow cytometry. The cytotoxicity of the HSV-specific CD4+ CTLs appeared to be Ca2+-dependent and was almost completely inhibited by concanamycin A, a potent inhibitor of the perforin-based cytotoxic pathway. Although the Fas/Fas ligand system has been reported to be the most important mechanism for CD4+ CTL-mediated cytotoxicity in the murine system, the present findings strongly suggest that granule exocytosis, not the Fas/Fas ligand system, is the main pathway for the cytotoxicity mediated by HSV-specific human CD4+ CTLs.

Anti-Bacterial Agents↗
PubMed1999

Down-regulation of CXCR4 by human herpesvirus 6 (HHV-6) and HHV-7.

Recent studies have demonstrated that human herpesvirus 6 (HHV-6) and HHV-7 interact with HIV-1 and alter the expression of various surface molecules and functions of T lymphocytes. The present study was undertaken to clarify whether coreceptors for HIV-1, CXCR4 and CCR5, are necessary for HHV-6 and HHV-7 infection. Although CXCR4 and CCR5 appeared not to be the coreceptors for these viruses, marked down-regulation of CXCR4, but not CCR5, was detected in HHV-6 variant A (HHV-6A)-, HHV-6 variant B (HHV-6B)-, and HHV-7-infected cells. Down-regulation of CXCR4 resulted in impairment of chemotaxis and a decreased level of elevation of the intracellular Ca2+ concentration in response to stromal cell-derived factor-1. Northern blot analysis of mRNAs extracted from HHV-6A-, HHV-6B-, and HHV-7-infected CD4+ T lymphocytes demonstrated a markedly decreased level of CXCR4 gene transcription, but the posttranscriptional stability of CXCR4 mRNA was not significantly altered. These data demonstrate that unlike HIV-1, HHV-6 and HHV-7 infections do not require expression of CXCR4 or CCR5, whereas marked down-regulation of CXCR4 is induced by these viruses, suggesting that HHV-6 and HHV-7 infections may render CD4+ T lymphocytes resistant to T lymphocyte-tropic HIV-1 infection.

Antibodies, Monoclonal↗
PubMed1999

Stimulation by low concentrations of fluoride of the proliferation and alkaline phosphatase activity of human dental pulp cells in vitro.

Fluoride has been used for decades, either systemically or topically, to prevent dental caries. The purpose of this study was to clarify the effects of low concentrations of fluoride on proliferation, differentiation and extracellular-matrix synthesis in normal human dental pulp cells (DP-1 and DP-2) in vitro. The effects were compared with those on a human osteoblastic osteosarcoma cell line, TE-85. Fluoride at micromolar concentrations significantly and dose-dependently stimulated [3H]thymidine incorporation into DNA in DP-1, DP-2 and TE-85 cells, with optimal effects around 50 microM, by 127 +/- 7%, 124 +/- 0.6% and 152 +/- 13.4%, respectively. To assess the potential influence of fluoride on cell differentiation, the effects of mitogenic concentrations on alkaline phosphatase activity were measured. Fluoride significantly increased the enzyme's activity in DP-1 and TE-85 by 177 +/- 12% and 144 +/- 12.3%. To evaluate the effect on extracellular-matrix synthesis, the synthesis of type I collagen was indirectly determined by an assay of procollagen type I c-peptide production. Fluoride significantly increased that production by 150 +/- 8.7% in TE-85, but not in either DP-1 or DP-2. These observations suggest that fluoride, if used at low concentrations, could be a useful therapeutic agent where increased regeneration of dentine is desired, such as after pulp amputation, by stimulating the proliferation and differentiation of the dental pulp cells.

Alkaline Phosphatase↗
PubMed1999

Influence of spironolactone on neonatal screening for congenital adrenal hyperplasia.

AIM: To determine if the diuretic spironolactone cross reacts with 17alpha-hydroxyprogesterone (17OHP) in an enzyme linked immunosorbent assay (ELISA) kit used for the mass screening of congenital adrenal hyperplasia. METHODS: Concentrations of 17OHP on a blood filter paper disc were measured using an ELISA kit (kit C-7: ENZAPLATE N-17alpha -OHP-7; Chiron, Tokyo, Japan). The cross reactivity of spironolactone and its metabolites with 17OHP was determined. The concentrations of spironolactone and its metabolites in blood were measured using HPLC (high performance liquid chromatography). RESULTS: Spironolactone cross reacted with 17OHP using kit C-7 (0.01%), by increasing 17OHP concentration in a dose dependent manner. The blood concentration of spironolactone and its metabolites was nearly 900 ng/ml, high enough to show an additive effect on the 17OHP concentration. About 12% of the false positive cases screened using the kit were due to the administration of spironolactone. CONCLUSIONS: Spironolactone interferes with 17OHP concentrations, leading to false positive test results for CAH.

17-alpha-Hydroxyprogesterone↗
PubMed1999

Caspaselike proteases activated in apoptotic photoreceptors of Royal College of Surgeons rats.

PURPOSE: To study the role of caspase-like proteases, especially roles of more extensively characterized caspase-1 and caspase-2, in apoptotic photoreceptor cell degeneration in Royal College of Surgeons (RCS) rats. METHODS: Both RCS and Sprague-Dawley rats were used. Cryosections of the retinas at various postnatal times were immunostained with antibodies against caspase-1 (interleukin-1beta-converting enzyme, ICE) and caspase-2 (Nedd2/Ich-1). Double staining with TdT-dUTP terminal nick-end labeling (TUNEL), propidium iodide, and the antibodies was also performed. To evaluate the time course of protein expression, western blot analysis was carried out. The temporal profile of caspase-like protease activity was studied using a fluorogenic tetrapeptide substrate, acetyl-tyrosyl-valyl-alanyl-aspartic acid alpha (4-methyl-coumaryl-7-amide) (Ac-YVAD-MCA). Intravitreal injection of a caspase-1 inhibitor, acetyl-tyrosyl-valyl-alanyl-aspartic-aldehyde (Ac-YVAD-CHO), at postnatal days 21 (P21) and P26 was performed to see if this caused a decrease in apoptotic cell number at P28. RESULTS: TUNEL-positive photoreceptors of RCS rats stained strongly with antibodies against caspase-1 and caspase-2. Double staining studies revealed that caspase-1 and caspase-2 were coexpressed in apoptotic cells. Western blot analysis showed that active forms of caspase-1-like and caspase-2-like proteases were upregulated at P28, concurrent with the peak in TUNEL-positive cells. The enzymatic activity of caspase-1-like protease was elevated in RCS rat retinas at P28, and the inhibitor of caspase-1 transiently reduced the number of the apoptotic photoreceptors. CONCLUSIONS: Activation of caspase-like proteases plays an important role in photoreceptor apoptosis of RCS rats.

Animals↗
PubMed1999

Measuring respiration of cultured cell with oxygen electrode as a metabolic indicator for drug screening.

New trend in methods for assessing pharmacological action to bacteria and cell is to measure their metabolic activities induced, while the conventional methods used population growth. We focused on respiration volume as an indicator of cell metabolism, and developed inexpensive disposable oxygen electrode sensor and multi-channel dissolved oxygen meters (DOX-10 and DOX-96KB). Using these instruments, cytotoxicity was measured for 48 hrs and the method showed superior features to conventional methods in its handiness of one step assay, and excellent adaptability to automated systems. Total usability of this oxygen electrode method is being evaluated in bacterial drug susceptibility test, anticancer drug susceptibility test, and alternatives to animal experiment.

Antineoplastic Agents↗
PubMed1998

Ataxia-telangiectasia in the Japanese population: identification of R1917X, W2491R, R2909G, IVS33+2T-->A, and 7883del5, the latter two being relatively common mutations.

We analyzed the data regarding six Japanese ataxia-telangiectasia (A-T) patients from four unrelated families, at the DNA level, to search for possible common mutations in the Japanese population. Among eight mutant alleles in the four families, c. 4612del165 (exon 33 skipping) was identified in two alleles, and c. 5749A to T (R1917X), c. 7471T to C (W2491R), c.7883de15, and c. 8725A to G (R2909G) were identified in one allele each. We found no mutations in the other two alleles. The IVS33 + 2T-->A mutation was identified at the genomic level as the cause of exon 33 skipping. We also identified the IVS33 + 2T-->A mutation in a Japanese patient ATL105 who was previously found to be a homozygote of c. 4612del165. W2491R and R2909G mutations were not detected in more than 100 control Japanese alleles. The latter is located in a highly conserved PI-3 kinase domain and is a completely conserved residue among ATM-related proteins. Taken together with previously documented mutations in five other Japanese A-T patients, IVS33 + 2T-->A and 7883del5 were identified in four and five alleles, respectively, in a total of 18 mutant alleles of Japanese A-T patients. These results suggest that these two mutations are relatively common mutations in the Japanese population.

Adolescent↗
PubMed1998

[Acute respiratory distress syndrome complicating imported Plasmodium falciparum malaria].

A 25-year-old male, who had returned from the Republic of Mali in Africa, was admitted to our hospital because of a 3-day history of high fever, on the first of October 1996. He was diagnosed as Plasmodium falciparum malaria by peripheral blood smear. From the admission day he was treated with quinine HCL, 1,500 mg per day, and sulfamethoxazole 2,400 mg trimethoprim 480 mg per day, but on October 2nd blood examination showed 35% parasite density and he was given mefloquine. However he was complicated with DIC on October 3rd, ARDS on October 5th. By anti-coagulant therapy and methylprednisolone pulse therapy he became afebrile and respiratory function improved rapidly. ARDS should be emphasized as a severe complication of imported severe malaria.

Adult↗
PubMed1998

[Anticancer susceptibility test method using general-purpose dissolved oxygen meter].

Drug susceptibility of cell can be rapidly measured by continuously monitoring its metabolic changes. We focused on respiration volume as a signal of metabolic change, and developed a new dissolved oxygen measuring system which can detect respiration volume of cells. The main feature of the system is the use of a new type bare oxygen electrode which can easily detect the changing rate of dissolved oxygen concentration. In this study, single type electrode was used to evaluate this rapid anticancer drug susceptibility test. The result obtained was almost equivalent to that with MTT method, which is a conventional method for susceptibility test of HL-60 to various kinds of anticancer drugs. We have also developed multi-type electrode plate with oxygen electrodes embedded in the bottom of 96-well plate, with which clinical evaluation of this method can be easily made.

Antineoplastic Agents↗
PubMed1997

A new method for studying the binding of human IgE to CD23 and the inhibition of this binding.

CD23, a low-affinity receptor for IgE (Fc epsilonRII), is a type II membrane-bound glycoprotein expressed on many hematopoietic cells, particularly activated B-cells. CD23 binds to IgE at a domain homologous to Ca2+-dependent (C-type) animal lectin. This paper describes a binding assay by which only the specific binding of IgE to CD23 expressed on Epstein-Barr virus (EBV)-transformed B-cell line, L-KT9 cells, can be detected. This assay is useful in the search for CD23 ligands among many chemical compounds, because it is easily carried out and does not require the use of any radiolabeled reagents. Using the assay, we investigated the inhibition of IgE binding to CD23 by fucose-1-phosphate which has been reported to inhibit the binding of sCD23 to IgE [Delespesse, G., Sarfati, M., Wu, C.Y., Fournier, S., Letellier, M., 1992. The low affinity receptor for IgE. Immunol. Rev. 125, 77.] and the binding of CD23 to CD21 [Pochon, S., Graber, P., Yeager, M., Jansen, K., Bernard, A.R., Aubry, T.-P., Bonnefoy, J.-Y., 1992. Demonstration of second ligand for the low affinity receptor for immunoglobulin E (CD23) using recombinant CD23 reconstituted into flourescent liposomes. J. Exp. Med. 176, 389.]. Although both alpha- and beta-L-fucose-l-phosphate/di(cyclohexylammonium) salt decreased the extent of IgE binding to CD23, the inhibitory effects were not due to alpha- or beta-L-fucose-1-phosphate but to cyclohexylamine. The inhibitory effect of cyclohexylamine was dose dependent and the effect was decreased when inhibition tests were carried out in the presence of a 10-fold excess of IgE. These results suggest that cyclohexylamine specifically interacts with the binding of CD23 and IgE.

B-Lymphocytes↗
PubMed1997

Alteration of proto-oncogenes during apoptosis in the oral squamous cell carcinoma cell line, SAS, induced by staurosporine.

Staurosporine (ST) has been reported to induce apoptosis in many kinds of cultured cells. The pathway of the apoptosis induced by ST is still not clear. Certain proto-oncogene expressions have been shown to be involved in the apoptotic pathway. The present study characterized apoptosis induced by ST in the oral squamous cell carcinoma cell line, SAS, focusing on the alteration of proto-oncogene expression. SAS showed typical apoptotic features upon exposure to ST. We compared the level of gene expression in apoptosis induced by ST with that by withdrawal of serum, which is a common system to induce apoptosis. By RT-PCR analysis, ST-induced apoptosis showed c-fos and c-jun up-regulation, whereas serum withdrawal-induced apoptosis showed c-jun up-regulation and the same levels of p21/waf-1 and c-myc. These results indicate that ST can rapidly induce apoptosis in SAS, possibly via a c-fos and c-jun pathway.

Apoptosis↗
PubMed1997

Nitric oxide synthase I immunoreactivity in the macula densa of the kidney is angiotensin II dependent.

The present study was undertaken to clarify the mechanism of the regulation of nitric oxide synthase (NOS)-I in the macula densa of the kidney. We determined the changes in NOS-I immunoreactivity of the macula densa relevant to the changes in systemic blood pressure (BP) and the renin-angiotensin system. Rats received four different types of treatment, and kidney sections were immunohistochemically stained for renin, NOS-I, and NOS-III. Plasma renin activity (PRA) and angiotensin II (Ang II) concentration were determined by radioimmunoassay. In the low-salt group, PRA, plasma Ang II, and the number of renin and NOS-I positively stained areas in the juxtaglomerular apparatus (JGA) were all increased, while BP and NOS-III in the glomerular capillaries did not change. In the desoxycorticosterone acetate (DOCA)-salt group, in contrast to the elevation of BP, PRA, plasma Ang II, and all immunohistochemical parameters were decreased. In the Ang II infusion group, BP, plasma Ang II, and the number of NOS-I positive glomeruli were increased, while PRA and renin staining were decreased. Administration of Ang II type 1 receptor (AT-1) antagonist TCV-116 significantly increased PRA, plasma Ang II, and the number of renin-positive glomeruli. However, BP, and NOS-I and NOS-III staining did not show any difference. These results clearly suggest that NOS-I in the macula densa changes in parallel with plasma Ang II, but not renin or systemic BP.

Angiotensin II↗
PubMed1997

[Sézary syndrome with two lymphocyte subpopulations expressing either CD4+/CD8- or CD4-/CD8+].

A 61-year-old man was admitted in March 1996 complaining of erythroderma, and Sézary syndrome was diagnosed. The leukocyte count was 33,590/microliter with 70.9% abnormal lymphocytes expressing two different types of antigenicity, either CD4+/CD8- (44.5%) or CD4-/CD8+ (48.9%). Clonal T-cell receptor beta rearrangement was not found on Southern blot analysis. He suffered repeated sepsis dueto methicillin-resistant Staphylococcus aureus. Combination chemotherapy was not effective for erythroderma and organomegaly, and deoxycoformycin revealed a transient effect. He died of MRSA enterocolitis in July 1996.

CD4 Antigens↗
PubMed1996

Light-sensitive response in melanophores of Xenopus laevis: II.Rho is involved in light-induced melanin aggregation.

Melanophores of the isolated tail fin of the Xenopus tadpole aggregate melanin granules in response to light. This aggregation was found to be inhibited by subcutaneous injection of exoenzyme C3 of Clostridium botulinum. A 26 kDa protein in homogenate obtained from the Xenopus tail fin was ADP-ribosylated by exoenzyme C3. This reaction was inhibited effectively by a monoclonal antibody, anti-Rho mab A5. raised against the small GTP-binding protein Rho. The extent of ADP-ribosylation depended on light and guanine nucleotide. Incubation under illumination partly reduced ADP-ribosylation and the reduction was restored by addition of guanine nucleotide during incubation. These findings suggest that Rho is involved in the photo-sensitive melanophore response as a signal transducer linking photo-stimuli to melanin granule translocation with Xenopus melanophores.

ADP Ribose Transferases↗
PubMed1996

Light-sensitive response in melanophores of Xenopus laevis: I. Spectral characteristics of melanophore response in isolated tail fin of Xenopus tadpole.

Melanophores in the isolated tail from the amphibian larvae Xenopus laevis, Hyla japonicus, Rana pirica, and Hynobius retardatus aggregated melanin granules in response to light and dispersed them when placed in darkness. The spectral characteristics for the melanin-aggregation response were examined by irradiating the Xenopus tail-fin locally (diameter, 2.1 mm) with monochromatic light (380-1,020 nm). The spectral region of wave length which induced melanosome aggregation depended on the light intensity but was limited to the visible spectrum. At low light intensity (1.59 microW/cm2, delta lambda = 5 nm), the aggregation response occurred in the spectral region between 400 and 600 nm and the maximum response was observed at 500 nm. This range is very close to the absorption spectrum of rhodopsin in the visual rod cell. Hypodermic injection of cGMP into isolated tail-fin induced a marked melanin-dispersion in spite of light-stimuli. When the tail-fin was treated with isobutylmethylxanthine (IBMX; phosophodiesterase inhibitor) in darkness and then was re-exposed to light, the aggregation response was inhibited. The photo-sensitive melanin aggregation was independent of a requirement for Ca2+ ions but melanosome dispersion in darkness was Ca(2+)-dependent. K(+)-rich Hanks' solution, ouabain (inhibitor of Na(+)-K(+)-ATPase) or nonactin (cation ionophore), which induced a change of the membrane potential of melanophores, inhibited the aggregation response when the melanophores were re-exposed to light after a period in darkness. These results suggest that the molecular mechanism of photoreception in melanophores of amphibian tadpoles is similar to that in visual cells.

1-Methyl-3-isobutylxanthine↗
PubMed1996

Human gingival fibroblast migration promoted by platelet-derived growth factor on titanium is correlated with release of urokinase type plasminogen activator.

The purpose of this study was to examine if the migration of human gingival fibroblasts on titanium was promoted by platelet-derived growth factor (PDGF) and whether the release of urokinase-type plasminogen activator (uPA) was correlated with it. The migration of the fibroblast on titanium was significantly promoted by PDGF in a wound healing assay (p < 0.001). The promotive effect was inhibited by aprotinin, a serine protease inhibitor used for the inhibition of uPA (p < 0.001). The conditioned medium when fibroblast migration was promoted contained a higher concentration of uPA than did that of the control. These results indicated that the promotive effect of PDGF on the migration of human gingival fibroblasts on titanium was correlated with the release of uPA from the fibroblasts.

Aprotinin↗