PubMed Health⌕ Search

Biomedical subjects

S Higa

Publications and source records attributed to S Higa.

At least 19 recordsLinked to original sources
PubMed2003

Administration of anti-interleukin 18 antibody fails to inhibit development of dermatitis in atopic dermatitis-model mice NC/Nga.

BACKGROUND: Interleukin (IL)-18 has been shown to activate basophils to produce histamine and IL-4 and to induce naive T cells to differentiate into T-helper (Th) 2 cells. However, when expressed together with IL-12, IL-18 induces Th1 cell development and inhibits IgE synthesis. Previously we reported that serum IL-18 levels were elevated in the sera from atopic dermatitis-model mice NC/Nga, prior to the onset and during the development of dermatitis. OBJECTIVES: We studied whether neutralization of IL-18 activity might affect dermatitis in NC/Nga mice, to investigate the role of IL-18 on dermatitis. METHODS: NC/Nga mice were given weekly anti-IL-18 antibody starting at 5 weeks of age to 13 weeks and development of dermatitis, scratching behaviour and serum IgE concentrations were evaluated. RESULTS: Continuous injections of anti-IL-18 antibody failed to inhibit the onset and development of dermatitis and IgE elevation. The treatment, rather, tended to lead to an exacerbation of dermatitis and scratching behaviour. In addition, the administration of anti-IL-18 antibody did not ameliorate the responsiveness of lymphocytes to IL-4, which was previously demonstrated as an immunological abnormality in the mouse. CONCLUSION: This study demonstrates that, at least in NC/Nga mice, IL-18, although excessively expressed before the onset of dermatitis, shows antiallergic actions.

Animals↗
PubMed2003

Association between interleukin-18 gene polymorphism 105A/C and asthma.

BACKGROUND: IL-18 has been shown to exert anti-allergic or allergy-promoting activities, but the existence of genetic polymorphisms in the coding regions of IL-18 gene has not been demonstrated. OBJECTIVE: The aim of this study was to investigate whether polymorphism is present in the coding regions of the IL-18 gene and, if so, to further analyse the association between polymorphism and asthma in a case-control study. METHODS: We screened the coding regions of the IL-18 gene for polymorphisms by using PCRsingle-stranded conformation polymorphism and direct sequencing of PCR products, followed by analysis of the association between polymorphism and asthma. RESULTS: We identified one polymorphism (105A/C) in the coding regions. The frequency of the 105A allele was significantly higher in asthmatic patients than in controls (P<0.01; odds ratio (OR)=1.83 (1.37-2.26)). Significant linkage disequilibrium was observed between the 105A/C and -137G/C polymorphisms in the 5' flanking region of the IL-18 gene (D=0.58, P<0.0001). However, in asthmatic patients the 105A allele was not associated with either total serum IgE or IL-18 levels. CONCLUSION: The 105A/C polymorphism of the IL-18 gene may be associated with the pathogenesis of asthma.

Adolescent↗
PubMed2002

Oral administration of persimmon leaf extract ameliorates skin symptoms and transepidermal water loss in atopic dermatitis model mice, NC/Nga.

BACKGROUND: We have previously shown that persimmon leaf extract and its major flavonoid constituent, astragalin, inhibited histamine release by basophils and that oral administration of these substances prior to the onset into an atopic dermatitis (AD) model mouse, NC/Nga, prevented development of dermatitis. OBJECTIVES: This study was designed to assess the clinical therapeutic effect of persimmon leaf extract and astragalin in NC/Nga mice suffering from dermatitis and the dose-response preventive effects of persimmon leaf extract on dermatitis and transepidermal water loss (TEWL). METHODS: The efficacy of persimmon leaf extract or astragalin in NC/Nga mice was judged by measurement of skin severity, scratching behaviour, serum IgE levels or TEWL. RESULTS: Oral administration of persimmon leaf extract (250 mg kg(-1)) or astragalin (1.5 mg kg-1) for 4 weeks into NC/Nga mice with overt dermatitis resulted in a decrease in the severity of the condition. The preventive effect of persimmon leaf extract on the dermatitis was dose-dependent and continuous intake of persimmon leaf extract significantly decreased its onset and development. In addition, TEWL was also suppressed at a persimmon leaf extract dose of 250 mg kg(-1). No significant adverse reaction by these substances could be observed. CONCLUSIONS: These observations suggest that persimmon leaf extract or the flavonoid astragalin may be alternative substances for the management of AD.

Administration, Oral↗
PubMed2001

Enhancement of T helper2 response in the absence of interleukin (IL-)6; an inhibition of IL-4-mediated T helper2 cell differentiation by IL-6.

Functional roles of interleukin (IL-)6 in T cell response were investigated. Mice deficient in IL-6 and wild mice were immunized with antigens (myelin oligodendrocyte glycoprotein or methylated BSA) and production of IL-4 and interferon (IFN)-gamma by regional lymph nodes was measured. IL-6 deficiency led to an enhancement of IL-4 and an inhibition of IFN-gamma production. Moreover, polyclonal stimulation of spleen T cells from unimmunized IL-6-deficient mice with anti-CD3 plus anti-CD28 antibodies (Abs) demonstrated an enhancement of T helper (Th)(2)responses. The presence of IL-6, however, augmented IL-4 production but it inhibited IFN-gamma expression by spleen T cells in response to polyclonal stimulation and by antigen-primed spleen T cells in response to re-challenge with the antigen. In contrast, the induction of spleen CD4-positive T cells into Th(2)cells in vitro by the anti-CD3 plus IL-4 was completely suppressed by exogenously added IL-6, whereas Th(1)differentiation of T cells by the anti-CD3 plus IL-12 was not inhibited by the presence of IL-6. Thus, these results indicate that IL-6 physiologically could modulate qualitative T cell response and suggest that it augments Th(1)responses partly through its inhibitory capability of IL-4-induced Th(2)differentiation of naive T cells.

Adjuvants, Immunologic↗
PubMed2001

Interleukin-18 enhances the production of interleukin-8 by eosinophils.

Interleukin-18 (IL-18), a proinflammatory cytokine, leads to IFN-gamma production by NK or T cells, induces Th1 differentiation and suppresses IgE synthesis by B cells when acting on responding cells together with IL-12. IL-18 also exhibits biological activities related to allergic inflammation such as histamine or IL-4 release from basophils and accumulation of eosinophils in localized lesions in allergic model mice. In this study, Reverse transcription (RT)-PCR analysis revealed that IL-18 receptor alpha chain mRNA was expressed in both freshly prepared eosinophils and two eosinophilic cell lines (YY-1 and EoL-1 cells). Flow cytometry and RT-PCR analyses revealed that the treatment of YY-1 cells with n-butyric acid promoted cell maturation and caused an enhancement of IL-18 receptor alpha chain expression. IL-18 had little effect on the survival of peripheral eosinophils, but it dose-dependently augmented IL-8 synthesis by YY-1 cells. In addition, IL-18-mediated up-regulation of IL-8 expression in eosinophils from a patient suffering from hyper-eosinophilic syndrome was confirmed. Our findings using peripheral blood eosinophils and eosinophilic cell line suggest the functional importance of IL-18 in the induction of IL-8 and a potential proinflammatory role in allergy.

Butyric Acid↗
PubMed2001

The human mitochondrial ribosomal protein genes: mapping of 54 genes to the chromosomes and implications for human disorders.

Mitochondria possess their own translational machinery, which is composed of components distinct from their cytoplasmic counterparts. To investigate the possible involvement of mitochondrial ribosomal defects in human disease, we mapped nuclear genes that encode mitochondrial ribosomal proteins (MRPs). We generated sequence-tagged sites (STSs) of individual MRP genes that were able to be detected by PCR. They were placed on an STS content map of the human genome by typing of radiation hybrid panels. We located 54 MRP genes on the STS-content map and assigned these genes to cytogenetic bands of the human chromosomes. Although mitochondria are thought to have originated from bacteria, in which the genes encoding ribosomal proteins are clustered into operons, the mapped MRP genes are widely dispersed throughout the genome, suggesting that transfer of each MRP gene to the nuclear genome occurred individually. We compared the assigned positions with candidate regions for mendelian disorders and found certain genes that might be involved in particular diseases. This map provides a basis for studying possible roles of MRP defects in mitochondrial disorders.

Chromosome Mapping↗
PubMed2001

Significant association between the progression of coronary artery calcification and dyslipidemia in patients on chronic hemodialysis.

Quantification of coronary artery calcification (CAC) determined by electron-beam computed tomography (EBCT), known as the CAC score (CACS), correlates with total plaque amount and coronary risk factors and strongly associates with maximal stenosis in the epicardial arteries. However, data are limited concerning the CACS in chronic dialysis patients, although atherosclerotic vascular disease is the most frequent complication. We examined the relation between coronary risk factors, metabolic factors of calcium and other minerals, and CACS progression in 24 dialysis patients. The mean patient age was 53 +/- 14 (SD) years, and mean duration of dialysis was 64 +/- 69 months. In each patient, the CACS was measured twice, with a mean interscan period of 17 +/- 3 months. The mean CACS progressed from 449 +/- 605 to 669 +/- 894 overall, and the mean change in CACS (DeltaCACS) was 220 +/- 78. Patients were divided into two groups: slow progressors, with DeltaCACS of 7.5 +/- 31 (n = 12), and rapid progressors, with DeltaCACS of 432 +/- 458 (n = 12). Triglyceride concentrations (198 +/- 65 versus 103 +/- 50 mg/dL; P < 0.001) were high, and high-density lipoprotein cholesterol (HDL-C) concentrations (46 +/- 11 versus 60 +/- 18 mg/dL; P < 0.05) were low in rapid progressors. Rapid progression of CAC was associated with high triglyceride and low HDL-C concentrations. The clinical significance of these observations remains to be determined.

Adult↗
PubMed2001

Interleukin-18 is elevated in the sera from patients with atopic dermatitis and from atopic dermatitis model mice, NC/Nga.

BACKGROUND: Several lines of in vitro and in vivo studies have demonstrated that interleukin-18 (IL-18) shows both antiallergic and allergy-promoting activities. But its expression in allergic diseases remains unknown. METHODS: Serum IL-18 levels from atopic dermatitis (AD) model mice, NC/Nga and control mice and from patients with AD and healthy volunteers were measured by ELISA. The relationship between IL-18 levels and serum IgE levels or clinical severity was also examined. RESULTS: Serum IL-18 levels from NC/Nga mice were significantly increased compared to those from control mice. The elevation of IL-18 in the sera was observed prior to the onset and during the development of dermatitis in NC/Nga mice. In addition, IL-18 levels in the sera from patients with AD were significantly (p < 0.05) elevated compared to those from healthy volunteers. However, serum IL-18 levels tended to correlate negatively with serum IgE levels in patients with AD and NC/Nga mice. CONCLUSION: IL-18 is overexpressed in AD.

Adolescent↗
PubMed2001

[Migraine and nerve block].

Migraine is essentially an episodic headache usually accompanied by neurological disorder, vomiting, photo- and phonophobia and malaise. The sensory nerves in the cerebral blood vessels are activated during migraine attack. The trigeminal systems is the sensory system that innervation cranial vessels and dura mater via its first ophthalamic division. Pain fibers from the trigeminal nerve descends to the second cervical cord segment where fibers from the occipital region transverse the dorsal root ganglion to converge on second order neurons. C2 root ganglion block therapy is the most efficacious treatment of the acute attack of migraine. Stellate ganglion block is a usefulness of amelioration of the sensory nerves of the intracranial vessels and prevention of migraine headache.

Ganglia, Spinal↗
PubMed2000

The human ribosomal protein L6 gene in a critical region for Noonan syndrome.

We have determined the genomic structure of the human ribosomal protein L6 gene (RPL6) and assigned it to the interval containing the Noonan syndrome locus. RPL6 spans 4415bp and consists of seven exons and six introns. The first exon is only 19bp in length, containing a 5' non-coding region and a polypyrimidine tract. The second exon starts with the initiator ATG. Although the overall structure of the protein is highly conserved among mammalian species, there is significant variation in the N-terminal portion. We have refined the position of RPL6, using two different radiation hybrid panels. RPL6 was mapped to chromosome 12q24.1 between the markers D12S84 and D12S861, which is in the critical region for Noonan syndrome.

Amino Acid Sequence↗
PubMed2000

Persimmon leaf extract and astragalin inhibit development of dermatitis and IgE elevation in NC/Nga mice.

BACKGROUND: We previously found that persimmon leaf extract contains antiallergic substances that inhibit histamine release by human basophilic cell line KU812 in response to cross-linkage of FcepsilonRI. OBJECTIVES: The purpose of this study was to identify substances in the persimmon leaf extract that are responsible for the effect and to examine their in vivo effects on the allergic mouse model. METHODS: HPLC analysis of persimmon leaf extract was done to measure its content. Inhibitory activity of persimmon leaf extract or its major constituent of flavonoids (astragalin) on the histamine release by KU812 cells was examined. To investigate the effects of these substances in vivo, models of passive cutaneous anaphylaxis and atopic dermatitis mice (NC/Nga) were used. RESULTS: Persimmon leaf extract or astragalin inhibited histamine release from KU812 in response to cross-linkage of FcepsilonRI. Oral intake of both substances dose dependently inhibited passive cutaneous reactions. Moreover, oral administration of these substances to NC/Nga atopic dermatitis-model mice led to a striking suppression of the development of dermatitis, scratching behavior, and serum IgE elevation. Histologic analyses revealed that infiltration of inflammatory cells, especially degranulated mast cells, thickening of the epidermis, and prominent hyperkeratosis, were significantly reduced. Immunologic studies showed that the capacity of spleen T cells to produce both IL-4 and IL-13, but not IFN-gamma, was downregulated by means of oral intake of these substances. CONCLUSION: This study demonstrates a novel activity of astragalin and the dramatic effect of persimmon leaf extract and astragalin on atopic dermatitis-model mice.

Administration, Oral↗
PubMed1999

Gene organization and sequence of the region containing the ribosomal protein genes RPL13A and RPS11 in the human genome and conserved features in the mouse genome.

We have determined the organization and sequence of the region containing two ribosomal protein (rp) genes in the human and mouse genomes. The two genes, human RPL13A and RPS11, and mouse Rpl13a and Rps11, are tandemly located in both genomes with an interval of only 4.6kb in the case of the human genes and 1.6kb in the case of the mouse genes. The human RPL13A and RPS11 are 4236bp and 3254bp in length and comprise eight and five exons respectively, whereas the mouse Rps11 is 1951bp long and has five exons. Structural comparison of these genes, including previously reported mouse Rpl13a, revealed a significant conservation of sequences in the promoter regions. Although most rp genes are dispersed throughout the human genome, the conserved features and adjacent localization indicate possible coordinate transcription of the two genes. Furthermore, we have found that four small nucleolar RNA (snoRNA) genes are located in the introns of the two rp genes, both human and mouse. U32, U33, and U34 snoRNAs are encoded in introns 2, 4, and 5 of RPL13A respectively, and U35 in the sixth intron of RPL13A and the third intron of RPS11. The same organization of these snoRNA genes was also observed in the case of the mouse genes.

Animals↗
PubMed1998

High-resolution mapping of ribosomal protein genes to human chromosome 19.

In a systematic effort for mapping of all the human ribosomal protein (rp) genes, we have found that an unusually large number (12) of rp genes are present on chromosome 19 and subsequently determined their locations on the chromosome by a radiation-hybrid procedure. For this, we isolated cosmid clones corresponding to each gene and placed nine of them on a metric physical map of chromosome 19. Although most genes are scattered over the chromosome, we found three genes are clustered in a 0.6-Mb region at 19q13.3 and two of them, RPL13A and RPS11, within a single cosmid only 4.3 kb apart. To explore a possible relationship between rp gene defects and human disease, we compared map positions of the rp genes and disease loci on chromosome 19, which led us to find RPS9 gene in the same interval as the gene for retinitis pigmentosa 11. The disease locus has previously been mapped to the 6-cM interval at 19q13.4 between markers D19S572 and D19S926, which corresponds to less than 2-Mb region on the metric physical map. We mapped RPS9 about 800 kb distal to D19S572.

Base Sequence↗
PubMed1998

Direct effects of thyroid hormones on rat coronary artery: nongenomic effects of triiodothyronine and thyroxine.

To determine whether thyroid hormones, triiodothyronine (T3) and thyroxine (T4), have any direct, nongenomic effects on vascular smooth muscle cells, we evaluated the effects of these hormones on rat coronary arteries. Bolus injection of T3 or T4 elicited a transient, dose-dependent decrease in coronary perfusion pressure (CPP), as well as an increase in arterial vasodilation. Vasodilation occurred immediately after injection, peaked at 15 seconds, and lasted 80 seconds. Reverse T3 had no effect on CPP or vasodilation. The rapidity of these effects suggests that they are not mediated by the T3-nuclear receptor, but are direct, nongenomic effects of thyroid hormones. Our results also suggest that thyroid hormones may play a role in preventing myocardial ischemia by inducing coronary artery vasodilation.

Animals↗
PubMed1996

U14 snoRNAs are encoded in introns of human ribosomal protein S13 gene.

During the mapping and sequencing of human ribosomal protein genes, we have found that U14 small nucleolar RNAs (snoRNAs) are encoded in introns of the ribosomal protein S13 gene. PCR cloning and sequencing have been employed to obtain the intron-containing (functional) human S13 gene and to eliminate a number of the processed pseudogenes. The S13 gene consists of six exons and five introns and spans a genomic region of 3.3 kb. U14 snoRNA genes are positioned in introns 3 and 5 of the S13 gene. A sequence comparison of the U14 genes in human and Xenopus laevis revealed that the regions involved in binding to 18S rRNA and the consensus (boxes C and D) of sequences for snoRNAs are highly conserved among the genes in the two species.

Base Sequence↗