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J Hayakawa

Publications and source records attributed to J Hayakawa.

At least 55 records · Page 3Linked to original sources
PubMed1996

Adult thymus contains dendritic epidermal T cell precursors that home to the epidermis in irradiated, but not in normal, mice.

It was generally assumed that Vgamma5+ fetal thymocytes are the only cells capable of homing to the epidermis. However, we have recently demonstrated that reconstitution of thymectomized irradiated mice with T-cell-depleted bone marrow (BM) cells results in the appearance of donor-type CD8+, TCR-alphabeta+ dendritic epidermal T cells (DETC) phenotypically distinct from their normal gammadelta+ counterparts. In the present study, we found that the epidermis of lethally irradiated, BM-reconstituted (XBM) mice was also repopulated by DETC of host origin as well as donor BM-derived DETC and that the host-derived DETC were rarely detected in the epidermis of athymic BM chimeras (ATXBM). This result indicates that the host-derived DETC are originated from intrathymic radioresistant cells that may share migratory capacities with the fetal thymocytes. We demonstrated that transfer of radioresistant intrathymic precursor cells into ATXBM mice resulted in the appearance of donor-type CD8+, TCR-alphabeta+ DETC. Contrary to our initial expectation, however, transferred normal adult thymocytes also gave rise to donor-type DETC with frequency similar to radioresistant thymocyte-derived DETC. These thymocyte-derived DETC were phenotypically similar to those derived from BM cells but differed in some respects. Tissue tropism by the CD8+ subset was observed only for the epidermis, but not for other lymphoid organs, such as lymph nodes. The epidermis of normal mice, unlike that of irradiated mice, was refractory to the appearance of the thymus-derived DETC. These results suggest that prior irradiation of the host may confer a susceptibility of the epidermis to repopulation of DETC precursors, which are otherwise incapable of migrating into the epidermis. This provides an explanation for why CD8+, TCR-alphabeta+ DETC of adult thymus or BM origin are rarely detected in the normal epidermis, but abundantly observed in the irradiated mice.

Aging↗
PubMed1996

Carnitine transport defect in fibroblasts of juvenile visceral steatosis (JVS) mouse.

Juvenile visceral steatosis (JVS) mice are associated with systemic carnitine deficiency (Kuwajima, et al., 1991). In order to investigate the cause of this deficiency, we compared fibroblast carnitine transport activities in normal mice and JVS mice. The kinetic analysis showed that in formal fibroblasts, the Km and Vmax values for saturable uptake was 15.6 microM and 2.56 pmol/min/mg protein, respectively. In JVS fibroblasts, however, saturable uptake was not observed. There was no great difference in the linear component of uptake between normal and JVS fibroblasts. At the physiological concentration (50 microM) of carnitine, the fibroblast carnitine transport activity in JVS mice was decreased to 18% of that in normal mice. Thus there is hardly any carnitine transport activity in the fibroblasts of JVS mice, indicating that the JVS mouse can be regarded as an animal model of primary carnitine deficiency.

Animals↗
PubMed1996

Definition of the locus responsible for systemic carnitine deficiency within a 1.6-cM region of mouse chromosome 11 by detailed linkage analysis.

Carnitine is an essential cofactor for oxidation of mitochondrial fatty acids. Carnitine deficiency results in failure of energy production by mitochondria and leads to metabolic encephalopathy, lipid-storage myopathy, and cardiomyopathy. The juvenile visceral steatosis (JVS) mouse, an animal model of systematic carnitine deficiency, inherits the JVS phenotype in autosomal recessive fashion, through a mutant allele mapped to mouse chromosome 11. As a step toward identifying the gene responsible for JVS by positional cloning, we attempted to refine the jvs locus in the mouse by detailed linkage analysis with 13 microsatellite markers, using 190 backcross progeny. Among the 13 loci tested, 5 (defined by markers D11Mit24, D11Mit111, D11Nds9, D11Mit86, and D11Mit23) showed no recombination, with a maximum lod score of 52.38. Our results implied that the jvs gene can be sought on mouse chromosome 11 within a genetic distance no greater than about 1.6 cM.

Animals↗
PubMed1996

Resistance to cutaneous graft-vs.-host disease is not induced in T cell receptor delta gene-mutant mice.

The function of murine dendritic epidermal cells (dEC) remains largely speculative, probably because of the lack of a suitable in vivo model, although previous studies suggest that gamma/delta+ dEC may have originally evolved to serve as a self-protection mechanism(s). Our previous study demonstrated that the epidermis of mice that had spontaneously recovered from cutaneous graft-vs-host disease (GVHD) induced by local injection of CD4+ autoreactive T cells contained unexpectedly large numbers of dEC and became resistant to subsequent attempts to induce GVHD in a site-restricted manner, suggesting that the resistance is mediated by dEC. However, because alpha/beta+ dEC as well as gamma/delta+ dEC were greatly increased in number in the epidermis, it was unclear whether gamma/delta+ dEC are indeed responsible for this protection. The availability of this murine model and mice selectively lacking gamma/delta T cells as a result of disruption of the T cell receptor C delta gene segment allowed us to investigate the role of gamma/delta+ dEC. In the epidermis of gamma/delta T cell-deficient mice (delta-/-), a congenital lack of gamma/delta+ dEC was substituted for by alpha/beta+ dEC of either a CD4-8+ or a CD4-8- phenotype. After intradermal injection of the autoreactive T cells, delta-/- mice developed significantly enhanced delayed-type hypersensitivity responses and cutaneous GVHD, which persisted longer than in heterozygous littermate controls (delta+/-). Surprisingly, resistance to the cutaneous GVHD was not induced in the epidermis of delta-/- mice after spontaneous recovery from the GVHD, whereas the "susceptible" epidermis of delta-/+ mice contained large numbers of alpha/beta dEC comparable to those in "resistant" epidermis of delta+/- mice. Injection of day 16 fetal thymocytes from wild-type mice into delta-/- mice resulted in the appearance of donor-type gamma/delta+ dEC in the epidermis, and reconstitution with gamma/delta+ dEC restored the protective immune response of the epidermis against the GVHD to nearly normal levels. These results indicate that gamma/delta+ dEC are responsible for the site-restricted protection against cutaneous GVHD.

Animals↗
PubMed1996

Altered expression of carnitine palmitoyltransferase II in liver, muscle, and heart of mouse strain with juvenile visceral steatosis.

We conducted a quantitative study of the effect of carnitine deficiency on the mRNA level of carnitine palmitoyltransferase II in the liver, muscle and heart of mice with juvenile visceral steatosis, a strain that is systematically deficient in carnitine. The amount of carnitine palmitoyltransferase II mRNA was increased in liver and muscle of homozygotes, as compared with heterozygotes and normal controls, at 2, 4, and 8 wk of age. The mRNA levels of this enzyme were normalized after carnitine administration. The mRNA level of carnitine palmitoyltransferase II in the heart was increased only at 8 wk, and was not affected by carnitine administration. These results suggest that carnitine displays some effect on the mRNA level of the carnitine palmitoyltransferase II gene in liver and muscle, probably through fatty acid metabolic change.

Ammonia↗
PubMed1996

Disordered expression of glycolytic and gluconeogenic liver enzymes of juvenile visceral steatosis mice with systemic carnitine deficiency.

A quantitative study of the effect of carnitine deficiency on expression of glycolytic and gluconeogenic enzymes was performed using juvenile visceral steatosis mice which are systemically deficient in carnitine. The amounts of glucokinase and L-type pyruvate kinase mRNA were reduced in homozygotes, compared to heterozygotes and normal controls at 2 and 8 weeks. Liver-type phosphofructokinase, however, did not differ significantly. The abundance of fructose 1,6-bisphosphatase mRNA was unchanged at 2 and 8 weeks. The level of phosphoenolpyruvate carboxykinase mRNA was increased slightly at 2 weeks, but not at 8 weeks. A part of these changes could not be explained by the plasma glucose or insulin level. Carnitine administration restored the mRNA of these enzymes to normal levels. These results suggest that carnitine deficiency affects the expression of these liver enzymes.

Age Factors↗
PubMed1996

Increased expression of carnitine palmitoyltransferase I gene is repressed by administering L-carnitine in the hearts of carnitine-deficient juvenile visceral steatosis mice.

The juvenile visceral steatosis (JVS) mouse is a novel mutant animal for studying systemic carnitine deficiency. The importance of the model has been pointed out in carnitine-deficient cardiac hypertrophy, since cardiomyopathy has been often improved after oral carnitine therapy in human systemic carnitine deficiency. To understand the effects of carnitine deficiency on gene expression in the heart, we tried to find the genes regulated by carnitine by means of a modified differential display procedure. Carnitine palmitoyltransferase I (CPT I) was one of the isolated genes. The level of CPT I gene expression in the ventricles of the JVS mice was at least three- to sixfold that of normal mice as judged by reverse transcription-polymerase chain reaction (RT-PCR). When the JVS mice were treated with carnitine, CPT I gene expression was repressed to the level of normal mice. Therefore, the increased expression of the CPT I gene was associated with carnitine deficiency.

Amino Acid Sequence↗
PubMed1996

[University education in geriatrics. Present status and future plans of universities regarding the development of a program in geriatrics].

Because the number of people who reach an advanced age has been increasing at an unprecedented rate in Japan, geriatricians are expected to play a central role in health care for the elderly. However, only 16 out of 80 medical schools (20 percent) now have departments of geriatrics for undergraduate education. To develop undergraduate education in the field of geriatrics, a survey was sponsored by the Research Projects on Aging and Health (Health Science Research Grant the Ministry of Health and Welfare of Japan). A questionnaire regarding the present status and future plans of the university about a program in geriatrics, was sent to deans of medical faculties or vice-presidents of medical schools. The questionnaire included questions about current status and future plans regarding undergraduate geriatric education, the presence of a department or clinic of geriatrics, educational requirements in the field of geriatrics, opportunities for practice, institutions of practice, research on geriatrics, and other suggestions. The response rate was 93.7 percent (74/79). Departments or clinics of geriatrics had been established in 15 institutions (20.3 percent) and were planned in 18 (24.3 percent). Undergraduate education in geriatrics was considered necessary in 73 schools (98.7 percent) and indispensable as an obligatory subject in 56 (75.7 percent). Clinical practice was considered more important and effective than lectures in 50 schools (63.3 percent). Coordinated lectures on basic biomedical gerontology (such as mechanism of aging) and geriatric medicine for chronic degenerative diseases such as senile dementia were considered essential to the curriculum. In practicing geriatrics, experience in providing medical care to aged patients as well as social support and a welfare system for the aged is emphasized. Institutions, nursing homes, and geriatric hospitals outside medical schools be easily accessible. It was generally agreed that geriatrics should be taught in advanced classes. In conclusion, medical schools in Japan regard undergraduate education in geriatrics as necessary and agree on the optimal curriculum, but it is not universally implemented.

Education, Medical, Undergraduate↗
PubMed1996

[Portal and peripheral blood insulin concentrations and arterial ketone body ratio before and after glucose infusion during gastrectomy].

The effect of glucose infusion on portal and peripheral blood immunoreactive insulin (IRI) concentrations and arterial ketone body ratio (AKBR) during gastrectomy were evaluated on twenty patients divided into two groups. Portal and peripheral blood IRI concentrations, AKBR, total ketone body concentration (TKB: acetoacetate + beta-hydroxybutyrate), and blood glucose were determined before and 30, 60, and 120 minutes after 25g glucose infusion in 30 minutes in ten patients (group 1) and 50 g glucose infusion in 30 minutes in ten patients (group 2). In both groups, the rate of increase in the portal blood IRI concentration was markedly higher than that in the peripheral blood IRI concentration after glucose infusion and AKBR increased and TKB decreased with the increase of the portal blood IRI concentration. These findings suggest that the peripheral blood IRI concentration does not reflect the pancreatic insulin secretion after glucose infusion during surgery and that portal insulin plays an important role for elevating and maintaining AKBR at higher levels. On the other hand, in both groups, the blood glucose had its peak just after completion of glucose infusion and then decreased gradually. After glucose infusion, however, the blood glucose in group 2 increased markedly and was significantly higher than that in group 1. It is suggested that, during surgery, glucose infusion rate of 50 g in 30 minutes may be too rapid.

Blood Glucose↗
PubMed1996

New immunodeficient mouse strains bred by introducing beige and xid mutations into the KSN nude strain.

We introduced two mutant genes (beige or bg, which induces a deficiency of natural killer activity, and xid, which decreases the production of immunoglobulins) into KSN nude mice with high reproductive performance. At first we produced the KSN-bg/bg(nu/nu) (KSN-bg) and KSN-xid/xid(nu/nu) (KSN-xid) congenic strain by backcross (cross-intercross method). After we identified homozygosity at the biochemical locus and polymorphic microsatellite loci, we mated KSN-bg and KSN-xid mice, and selected the KSN-xid/xid;bg/bg(nu/nu) (KSN-BNX) mice from the progeny. Furthermore we introduced the non-nude gene, which originated from CBA/N, into the KSN strain and produced KSN-nu/+ (KS) mice that have the same genetic background except for the nu locus. All strains had as high a reproductivity rate as the parental KSN mice. The KSN-xid and KSN-BNX mice had a reduced percentage of B220-positive cells in the spleen compared with KSN and KSN-bg mice, but they had increased percentages of Thy-1 and asialo GM1-positive cells. The serum immunoglobulin concentrations of BNX were as low as those of KSN-xid mice. Both KSN-bg and KSN-BNX mice had deficient natural killer activity in the spleen, whereas KSN-xid mice had increased natural killer activity. Compared with nude mice, the growth of the human thyroid tumor cell line transplanted subcutaneously was enhanced in BNX mice. These KSN, KSN-bg, KSN-xid, KSN-BNX, and KS nice not only are of value for use in various fields as the hosts of xenograft but also are good models of the combination effect of multiple immunodeficient genes.

Animals↗
PubMed1995

Interaction of the cell-binding domain of fibronectin with VLA-5 integrin induces monokine production in cultured human monocytes.

The effect of fibronectin on IL-1 alpha, IL-1 beta, tumour necrosis factor-alpha (TNF-alpha), and IL-6 production was investigated with cultured monocytes isolated from human peripheral blood. Monokine concentrations were determined by both ELISA and bioassay. Fibronectin markedly stimulated the secretion of IL-1 alpha, IL-1 beta, TNF-alpha and IL-6 from cultured monocytes in a dose-dependent manner, with the maximal effect apparent within 24 h. Northern blot analysis revealed a marked increase in the abundance of mRNA specific for each monokine on exposure of monocytes to fibronectin. Monoclonal antibodies to the alpha chain of very late antigen (VLA)-5, the beta 1 integrin, the alpha chain of Mac-1, and the beta 2 integrin, as well as the synthetic peptide of GRGDSP (which corresponds to the cell-binding domain of fibronectin), inhibited (> 50%) fibronectin-induced monokine production. Monoclonal antibodies to the alpha chain of VLA-4, and the alpha chain of LFA-1, as well as the synthetic peptide CS-1 (which corresponds to the alternatively spliced connecting segment of fibronectin) and the control peptide GRADSP, had no inhibitory effect on monokine production. A MoAb, R60, that recognizes an epitope of the fibronectin molecule that includes the RGD sequence, inhibited monokine production, whereas the MoAb Y16, which recognizes another epitope of fibronectin not including RGD, did not. These results indicate that fibronectin-induced production of IL-1 alpha, IL-1 beta, TNF-alpha and IL-6 from cultured monocytes is mediated predominantly by interaction of the cell-binding domain of fibronectin with VLA-5, although Mac-1 also may contribute to this effect of fibronectin. Our results indicate that the interaction of fibronectin with integrins may contribute to the cytokine network in inflammatory response.

Binding Sites↗
PubMed1995

Total structures and antimicrobial activity of bacitracin minor components.

Total structures of 13 minor components of bacitracin (BC) were proposed, and their antimicrobial activities were investigated. The components of BC including bacitracins A (BC-A) and F (BC-F) were isolated by preparative HPLC and were hydrolyzed under acidic conditions. The resulting amino aids were derivatized with 1-fluoro-2,4-dinitrophenyl-5-L-alanineamide and were separated by HPLC to determine their absolute configurations. It was found that the N-terminal amino acids of BC-A and its related components were epimerized during the hydrolysis to yield their enantiomers. The formation of these artifactual amino acids suggests that our previously proposed structures of the BC minor components are incorrect; therefore, the structures were corrected based on these results. The structures of the BC minor components were the same as that of BCs-A and -F except that one to three of the L-isoleucines, including the N-terminal one, were replaced by L-valines. These structures were confirmed by tandem mass spectrometry under fast atom bombardment (FAB) conditions and Frit-FAB liquid chromatography/mass spectrometry. Based on the UV spectra of the BC components determined by photodiode array detection-HPLC analysis, a new systematic nonmenclature was proposed for the minor components. The isolated components were also used for the determination of their minimal inhibition concentrations and it was found that BC-A is 2 approximately 8 times more potent than the other minor components against strains of Micrococcus luteus and Staphylococcus aureus.

Amino Acid Sequence↗
PubMed1995

[Portal and peripheral blood immunoreactive insulin concentrations after glucose infusion during gastrectomy].

We evaluated portal and peripheral blood immunoreactive insulin concentrations (IRI) after glucose infusion in patients undergoing gastrectomy. Seventy-four patients were divided into following two groups: 68 received 25g glucose infusion in an hour (glucose group), and the remainder received no glucose (control group). Portal blood IRI level in glucose group was about thirty-fold higher than that in control group. However, peripheral blood IRI did not correlate with portal blood IRI in glucose group. In addition, significant negative correlation between portal blood IRI and blood glucose was observed in glucose group. Our results reveal that adequate pancreatic insulin secretion occurs after glucose infusion during gastrectomy, but peripheral blood IRI does not reflect this pancreatic insulin secretion. The results also suggest that blood glucose may be regulated by the liver under these conditions.

Aged↗
PubMed1995

[Portal blood immunoreactive insulin concentration after glucose infusion in elderly patients during gastrectomy compared with younger patients].

We evaluated the effect of aging on portal blood immunoreactive insulin concentration, AKBR, and keton body concentration (acetoacetate + beta-hydroxybutyrate) after glucose infusion (25 g glucose in an hour) in patients undergoing gastrectomy. Twenty-seven patients studied were elderly (above 65 years) and twenty-eight were younger (below 60 years). There was no significant difference in portal blood immunoreactive insulin concentration after glucose infusion between the two groups of patients. In elderly patients, however, AKBR was significantly lower and keton body concentration was significantly higher than those in younger patients, and these imply that suppression of ketogenesis and activation of hepatic mitochondrial function due to insulin may be reduced in elderly patients. These findings suggest that, during gastrectomy, pancreatic insulin secretion may not be impaired in elderly patients, but insulin action may be attenuated with aging.

Aged↗
PubMed1994

Expression of recombinase-activating genes (RAG-1 and 2) in human decidual mononuclear cells.

Recombinase-activating genes (RAG-1 and RAG-2) are expressed in immature T or B lymphocytes and possess activity to induce V(D)J rearrangement in TCR and Ig genes. We examined their expression in human decidual and non-pregnant endometrial samples using a highly sensitive RT-PCR technique. Expression of RAG-1 and 2 was noted in all (13/13) pregnant decidual tissues obtained at different gestational stages. After anti-human Ig treatment to rule out the possibility of RAG-1,2 expression from decidual B-cells, strong expression of RAGs was still noted in B cell depleted decidual cells in contrast to lymph nodes and PBMC that lost RAG mRNA expression after this treatment. After FACS mediated cell sorting, strong expression of RAG-1,2 was noted in CD16-CD56bright cells and weak expression in CD3+ cells. Although CD16-CD56bright cells lack surface CD3, they express CD3 epsilon mRNA only detectable by RT-PCR. Our results suggest the nature of decidual CD16-CD56bright cells as a progenitor of extrathymic T cells that possess RAG-1 and 2 mRNA as markers of their immaturity, and possibly differentiate into CD3+ extrathymic T-cells in the decidua under the influence of trophoblastic cells. We propose the human decidua as a new site of extrathymic T-cells differentiation and propose possible roles of trophoblastic cells to attract progenitor lymphocytes of bone marrow origin and trigger their TCR rearrangement as thymic epithelial cells.

Adult↗
PubMed1994

Identification of unlawful food dyes by thin-layer chromatography-fast atom bombardment mass spectrometry.

A thin-layer chromatographic-fast atom bombardment mass spectrometric (TLC-FAB-MS) method incorporating an analyte condensation technique was established for the identification of the 27 food dyes consisting the twelve dyes permitted for use in foods and the fifteen unlawful dyes in Japan. The use of magic bullet [1,4-dithiothreitol-1,4-dithioerythritol (3:1)] as a matrix allowed the measurement of the FAB mass spectra of the food dyes except for Food Blue No. 2 (Indigo Carmine). The separation was performed on a C18-modified silica gel TLC plate using the following two solvent systems: methanol-acetonitrile-5% aqueous sodium sulphate solution (3:3:10) and methyl ethyl ketone-methanol-5% aqueous sodium sulphate solution (1:1:1). The condensation technique for concentration of a diffuse sample spot on the TLC plate improved the detection limit 4-20-fold with good reproducibility. The method was successfully applied to the identification of unlawful dyes in imported foods.

Chromatography, Thin Layer↗
PubMed1994

Primary defect of juvenile visceral steatosis (jvs) mouse with systemic carnitine deficiency is probably in renal carnitine transport system.

We investigated the reabsorptional system for carnitine in the kidney to elucidate the mechanism of carnitine deficiency in juvenile visceral steatosis (jvs) mice. Jvs mice had a higher rate of carnitine excretion at 10 days after birth than the controls, in spite of having no pathological acylcarnitine excretion in the urine. In an experiment to assay the uptake of carnitine using kidney slices, homozygous mutants showed significantly lower rates of Na-dependent carnitine uptake than controls. Heterozygous mice showed values of transport activity intermediate between homozygous mutants and homozygous controls. Scatchard plots (transport activity versus transport activity/carnitine concentration) revealed that the homozygous mutants had a defect in the high affinity site (Km = 58 microM) in the Na-dependent carnitine transport system in the kidney. These results indicate that the primary defect of jvs mice is most probably related to the system for reabsorption of carnitine in the kidney.

Absorption↗