Biomedical subjects

Y Kumazawa

Publications and source records attributed to Y Kumazawa.

At least 19 recordsLinked to original sources

PubMed2006

Interferon-gamma independent formation of pulmonary granuloma in mice by injections with trehalose dimycolate (cord factor), lipoarabinomannan and phosphatidylinositol mannosides isolated from Mycobacterium tuberculosis.

The mechanisms by which pulmonary granuloma formation is caused by administration of mycobacterial glycolipids such as trehalose dimycolate (TDM), lipoarabinomannan (LAM) and phosphatidylinositol mannosides (PIM) were investigated. When peritoneal and alveolar macrophages were stimulated with TDM, LAM and PIM in vitro, TDM exhibited the strongest tumour necrosis factor (TNF)-inducing activity. Responsiveness of macrophages from mice defected Toll-like receptor 4 (TLR4) was much higher than that of the wild-type mice. Although PIM and LAM also had a significant activity, LAM rather than PIM stimulated higher TNF-alpha production by alveolar macrophage. When mycobacterial glycolipids were injected as water-in-oil-in-water emulsion into mice via the tail vein, development of pulmonary granuloma in response to glycolipids were related closely to their TNF-inducing activity and TDM exhibited the strongest activity. Granuloma formation was observed not only in mice lacking interleukin (IL)-12 signalling but also interferon (IFN)-gamma knock-out mice. Granuloma formation caused by glycolipids correlated with TNF-alpha levels in lungs. Administration of anti-TNF-alpha monoclonal antibody into TDM-injected IFN-gamma knock-out mice decreased in granuloma formation, suggesting that development of pulmonary granuloma by mycobacterial glycolipids such as TDM is due to IFN-gamma-independent and TNF-alpha-dependent pathway.

Adjuvants, Immunologic↗

PubMed2004

TSH receptor-adenovirus-induced Graves' hyperthyroidism is attenuated in both interferon-gamma and interleukin-4 knockout mice; implications for the Th1/Th2 paradigm.

The role of the Th1/Th2 balance in the pathogenesis of murine Graves' hyperthyroidism is controversial. In BALB/c mice injected with adenovirus expressing TSH receptor (TSHR-adeno model), we found that suppression of TSHR-specific Th1 immune responses by exogenous interleukin-4 (IL-4), alpha-galactosylceramide or helminth (Schistosoma mansoni) infection was associated with inhibition of hyperthyroidism, indicating the critical role for Th1 cytokines. In contrast, BALB/c IL-4 knockout (KO), but not interferon-gamma (IFN-gamma) KO mice failed to develop Graves' hyperthyroidism when injected with TSHR-expressing M12 B lymphoma cells (TSHR-M12 model), suggesting the importance of Th2 cytokine IL-4. To reconcile differences in these two models, we used IL-4 KO and IFN-gamma KO BALB/c mice in the TSHR-adeno model. Unlike wild-type (wt) BALB/c mice in which 60% developed hyperthyroidism, only 13 and 7% of IL-4 KO and IFN-gamma KO mice, respectively, became hyperthyroid. Thyroid stimulating antibodies were positive in most hyperthyroid mice. TSHR antibody titres determined by TSH binding inhibition and ELISA were comparable in all three groups. IgG1 and IgG2a TSHR antibody titres were similar in IFN-gamma KO and wt mice, whereas IgG1 TSHR antibody titres and TSHR-specific splenocyte IFN-gamma secretion were lower in IL-4 KO than in IFN-gamma KO and wt mice, respectively. Our results clearly implicate both IFN-gamma and IL-4 in development of hyperthyroidism in the TSHR-adeno model. These data, together with the previous report, also indicate different cytokine requirements in these two Graves' models, with IFN-gamma being more important in the TSHR-adeno than the TSHR-M12 model. Moreover, our previous and present observations indicate a difference in the role of exogenous versus endogenous IL-4 in TSHR-adenovirus induced Graves' hyperthyroidism.

Adenoviridae↗

PubMed2002

Expression of glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase in a case of pulmonary epithelioid haemangioendothelioma.

This report describes a case of pulmonary epithelioid haemangioendothelioma in which the tumour cells expressed the glucocorticoid receptor and 11beta-hydroxysteroid dehydrogenase. The patient, a 15 year old girl, who had no other complaints or past illnesses, was found to have an abnormal shadow on a chest roentgenogram obtained at a school medical examination. Multiple nodular shadows in the bilateral lungs were also confirmed by computerised axial tomography scan. A diagnosis of pulmonary epithelioid haemangioendothelioma was made on the basis of lung biopsy specimens. The tumour cells were immunohistochemically positive for factor VIII related antigen, CD31, and CD34, but not surfactant apoprotein A. In addition, almost all of the tumour cells showed simultaneous expression of the glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase, suggesting that steroid treatment would be effective.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed2001

Mycobacterial cord factor, but not sulfolipid, causes depletion of NKT cells and upregulation of CD1d1 on murine macrophages.

Trehalose 6,6'-dimycolate (TDM, cord factor) has frequently been used as an adjuvant to stimulate antibody production. Although it also induces cellular immunity, detailed studies about the underlying events do not exist. To determine the kinetics of TDM-specific changes promoting a T helper 1 (Th1) response, we injected mice with TDM or 2,3,6,6'-tetraacyl trehalose 2'-sulfate (SL, sulfolipid), another mycobacterial trehalose-containing glycolipid without mycolic acid. TDM, but not SL, caused a strong increase in serum interferon-gamma (IFN-gamma) levels 2 days later, accompanied by expansion of natural killer (NK) cells. Subsequent TDM effects included depletion of normal-density CD4(+) NK1.1(+) TCRalpha/beta(intermediate) cells from day 7 on, upregulation of MHC class II and CD1d1 on macrophages (peaking on day 21), and an increased proportion of Th1 cells evident after 3 weeks. TDM, but not a similar glycolipid without mycolic acid, can therefore initiate a cascade of events starting with strong release of IFN-gamma and NK cell expansion, resulting in the appearance of macrophages activated for antigen presentation. Our data therefore provide the basis for optimized immunization schedules with TDM as the adjuvant component of a Th1 vaccine.

Adjuvants, Immunologic↗

PubMed2001

Immunological properties of trehalose dimycolate (cord factor) and other mycolic acid-containing glycolipids--a review.

Mycolic acids are characteristic fatty acids of Mycobacteria and are responsible for the wax-like consistence of these microorganisms. Decades of research revealed that mycolic acid-containing glycolipids, in particular trehalose-6,6'-dimycolate (TDM, cord factor) as their best-studied representative, exert a number of immunomodifying effects. They are able to stimulate innate, early adaptive and both humoral and cellular adaptive immunity. Most functions can be associated with their ability to induce a wide range of chemokines (MCP-1, MIP-1alpha, IL-8) and cytokines (e.g., IL-12, IFN-gamma, TNF-alpha, IL-4, IL-6, IL-10). This review tries to link well-known properties of mycolic acid-containing glycolipids, e.g., stimulation of cellular and humoral immunity, granuloma formation and anti-tumor activity, with recent findings in molecular immunology and to give an outlook on potential practical applications.

Adjuvants, Immunologic↗

PubMed2001

Ionic mechanisms underlying burst firing of layer III sensorimotor cortical neurons of the cat: an in vitro slice study.

We examined the ionic mechanisms underlying burst firing in layer III neurons from cat sensorimotor cortex by intracellular recording in a brain slice. Regular spiking was observed in 77.4% of 137 neurons in response to constant intracellular current pulses of 0.5- to 1-s duration. The rest of the neurons showed burst firing. An initial burst followed by regular-spike firing was seen in 71.0% of 31 bursting neurons. The rest of the bursting neurons (n = 9) exhibited repetitive bursting. In the bursting neurons, spikes comprising the burst were triggered from the afterdepolarization (ADP) of the first spike of the burst. We examined the ionic mechanisms underlying the ADP by applying channel-blocking agents. The ADP was enhanced (rather than blocked) by Ca2+ channel blockade. This enhancement of the ADP by Ca2+ channel blockade was apparent even after blockade of the afterhyperpolarization by apamin or intracellular Ca2+ chelation by EGTA. The firing rate of the regular-spiking cells was increased by apamin, intracellular EGTA or Ca2+ channel blockers. In 17.9% of the neurons examined (n = 56), these agents switched the regular-spiking pattern into a bursting one. Burst firing could not be changed to regular spiking by these agents. Four neurons that responded with a single initial burst in control solution responded with repetitive bursting after application of these agents. We conclude that the main function of Ca2+ influx in layer III neurons is to activate Ca2+-dependent K+ conductance, which prevents or limits burst firing. At a time when spike amplitude was unchanged, the ADP was blocked and the burst firing changed to regular spiking by extracellularly applied tetrodotoxin (TTX) or intracellularly applied N-(2,6-dimethylphenylcarbamoylmethyl) triethyl ammonium bromide (QX314). We concluded that a TTX- and QX314-sensitive Na+ current underlies the ADP and therefore contributes to the burst firing of layer III neurons from the cat cortex.

Action Potentials↗

PubMed2001

Differential clearance and induction of host responses by various administered or released lipopolysaccharides.

The clearance and activity of different types of lipopolysaccharide (LPS) released during infection with Gram-negative bacteria were investigated. When highly purified preparations differing in their specific endotoxin activity were administered intravenously to mice, the clearance of rough (R)-form LPS preparations from Salmonella minnesota and Escherichia coli was much faster than that of a smooth (S)-form LPS preparation from Salmonella abortus equi, but slower than that of lipo-oligosaccharides (LOS) preparations from Bordetella pertussis and Helicobacter pylori. After intraperitoneal infection with 10(7) and 10(8) CFU E. coli O111:B4, relatively high levels of LPS were detected dose-dependently in the plasma of infected mice and persisted for a long time. In addition, plasma sCD14 levels in infected mice were higher than in LPS-administered mice. These results indicate that continuously higher levels of plasma LPS followed by stronger host responses occur during infection and suggest that these differences between LPS-administered and infected mice should be taken into consideration when analyzing host responses induced by LPS.

Animals↗

PubMed2000

Phylogenetic position of turtles among amniotes: evidence from mitochondrial and nuclear genes.

Maximum likelihood analysis, accounting for site-heterogeneity in evolutionary rate with the Gamma-distribution model, was carried out with amino acid sequences of 12 mitochondrial proteins and nucleotide sequences of mitochondrial 12S and 16S rRNAs from three turtles, one squamate, one crocodile, and eight birds. The analysis strongly suggests that turtles are closely related to archosaurs (birds+crocodilians), and it supports both Tree-2: (((birds, crocodilians), turtles), squamates) and Tree-3: ((birds, (crocodilians, turtles)), squamates). A more traditional Tree-1: (((birds, crocodilians), squamates), turtles) and a tree in which turtles are basal to other amniotes were rejected with high statistical significance. Tree-3 has recently been proposed by Hedges and Poling [Science 283 (1999) 998-1001] based mainly on nuclear genes. Therefore, we re-analyzed their data using the maximum likelihood method, and evaluated the total evidence of the analyses of mitochondrial and nuclear data sets. Tree-1 was again rejected strongly. The most likely hypothesis was Tree-3, though Tree-2 remained a plausible candidate.

Animals↗

PubMed2000

Absence of interleukin-4 enhances germinal center reaction in secondary immune response.

The germinal center (GC) is a compartment for B cell differentiation and proliferation. Interleukin (IL)-4 has been considered essential for GC functioning. To define the role of IL-4 in GC reaction, immunohistology of draining lymph nodes (LNs) of IL-4 gene-targeted (IL-4(-/-)) mice was performed during secondary immune response. IL-4(-/-) mice were immunized with ovalbumin emulsified in Freund' complete adjuvant. Final antigen challenge was done 4 weeks later. IL-4(-/-) mice had a higher production of IgG2a and IgG2b and a lower production of IgG1 than those in wild-type (WT) mice. In comparison with WT mice, LNs of IL-4(-/-) mice on days 4 and 7 after final antigen challenge were larger and contained a markedly greater number of GCs, which showed marked size variations with a large number of small GCs and a small number of markedly large GCs. By day 14, the number of GCs decreased to the same level as that in WT mice. However, the LN size in IL-4(-/-) mice was still larger than that in WT mice due to the presence of markedly large GCs. Although well-developed complement receptor(+) follicular dendritic cell (FDC) networks were present in GCs of IL-4(-/-) mice, no FDCs of mature phenotype (CD23(+)) were observed in many of the small GCs. In conclusion, the absence of IL-4 enhanced GC reaction and specific antibody response of Th1-type. IL-4 may play an important role in inducing the appropriate magnitude of humoral immune response.

Animals↗

PubMed2000

Activity-dependent slow hyperpolarization in cat sensorimotor cortex in vitro.

The synaptic regulatory mechanism of resting membrane potential of layer III and V pyramidal neurons was analyzed intracellularly in the slice preparation of cat sensorimotor cortex. During the tetanic stimulation of white matter, subthreshold membrane depolarization was induced, and after that, a slowly developing hyperpolarization was induced in the normal solution. When the membrane potential showed a slow change, spike duration and input resistance did not change and evoked single synaptic response did not reveal the enhancement of slow IPSPs. However, afterhyperpolarization following action potential was enhanced. The slow hyperpolarization and the enhancement of afterhyperpolarization were not observed in the cells treated with an NMDA receptor antagonist or a calcium channel blocker Ni(2+) (50-100 microM), or the cells hyperpolarized more than -80 mV before the tetanic stimulation.

Action Potentials↗

PubMed2000

Sequence and mechanical implications of titin's PEVK region.

A widely used titin monoclonal antibody (9D10) was epitope mapped to the PEVK region in the I-band portion of titin. Sequence analysis of the titin PEVK region revealed a large number of 28 amino acid modules (termed "PPAK" repeats) alternating with glutamic acid rich segments. Species differences in cardiac rest tension could not be ascribed to differences in the PEVK length of the N2B titin isoform. The low rest tension generated by dog cardiac muscle also does not appear to be explained by the N2 and PEVK segment lengths in the N2A titin isoform.

Amino Acid Sequence↗

PubMed2000

Bone mineral density and osteo sono assessment index in adolescents.

The standard value for bone mineral density in the distal radius (R-BMD) and the osteo sono assessment index (OSI) in the os calcaneus for each sex and age in teenagers have not yet been fully reported. The R-BMD and OSI of junior and senior high school students were measured by dual energy X-ray absorptiometry (DEXA) or by a quantitative ultrasound technique. Subjects measured by DEXA included 635 junior and senior high school students (274 males and 361 females, aged 12-17 years). Ultrasound measurements were made for 2878 subjects (1733 males, 1145 females, aged 12-18 years). All subjects filled out questionnaires about their past history, family history, past and present eating habits, sports activities, and for females, the presence of menses, regularity of menses, and so on. The R-BMD in 15- to 17-year-old males was significantly higher than that in females. The R-BMD rate of increase in males was almost linear; the rate of increase in females was significantly highest from ages 12 to 13, after which R-BMD increased gradually. The OSI in 15- to 18-year-old males was significantly higher than that in females. The OSI rate of increase in males was almost linear from ages 12 to 17. The OSI in females, except in 14-year-olds, was roughly equal at each age. The OSI was significantly higher in those who regularly participated in sports, either currently or in the past. It was significantly higher in those who previously or currently consumed milk on a daily basis compared with those who had consumed little or no milk. To prevent osteoporosis, increasing peak bone mass is very important. Adequate calcium intake from dairy products which are rich in calcium and absorbed easily, and exercise in adolescence, are expected to result in increased bone formation and increased OSI.

Absorptiometry, Photon↗

PubMed2000

Molecular phylogeny of osteoglossoids: a new model for Gondwanian origin and plate tectonic transportation of the Asian arowana.

One of the traditional enigmas in freshwater zoogeography has been the evolutionary origin of Scleropages formosus inhabiting Southeast Asia (the Asian arowana), which is a species threatened with extinction among the highly freshwater-adapted fishes from the order Osteoglossiformes. Dispersalists have hypothesized that it originated from the recent (the Miocene or later) transmarine dispersal of morphologically quite similar Australasian arowanas across Wallace's Line, but this hypothesis has been questioned due to their remarkable adaptation to freshwater. We determined the complete nucleotide sequences of two mitochondrial protein genes from 12 osteoglossiform species, including all members of the suborder Osteoglossoidei, with which robust molecular phylogeny was constructed and divergence times were estimated. In agreement with previous morphology-based phylogenetic studies, our molecular phylogeny suggested that the osteoglossiforms diverged from a basal position of the teleostean lineage, that heterotidines (the Nile arowana and the pirarucu) form a sister group of osteoglossines (arowanas in South America, Australasia, and Southeast Asia), and that the Asian arowana is more closely related to Australasian arowanas than to South American ones. However, molecular distances between the Asian and Australasian arowanas were much larger than expected from the fact that they are classified within the same genus. By using the molecular clock of bony fishes, tested for its good performance for rather deep divergences and calibrated using some reasonable assumptions, the divergence between the Asian and Australasian arowanas was estimated to date back to the early Cretaceous. Based on the molecular and geological evidence, we propose a new model whereby the Asian arowana vicariantly diverged from the Australasian arowanas in the eastern margin of Gondwanaland and migrated into Eurasia on the Indian subcontinent or smaller continental blocks. This study also implicates the relatively long absence of osteoglossiform fossil records from the Mesozoic.

Animals↗

PubMed2000

Suppression of lethal toxicity of endotoxin by biscoclaurine alkaloid cepharanthin.

Suppressive effects of Cepharanthin (CE) on lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNFalpha) production followed by liver injury were investigated. Pretreatment with CE reduced limulus activity of LPS. Intraperitoneal treatment with CE 10 min before an i.v. challenge of LPS resulted in protection from LPS lethality in D-galactosamine (GalN)-sensitized BALB/c but not in C57BL/6 and C57BL/10ScSn mice. Treatment with CE before the LPS challenge significantly reduced serum TNF levels in a dose-dependent manner. The suppression was most effective when CE was administered 10 min before the LPS challenge. Increased levels of enzymes released from hepatocytes into the circulation, as a result of LPS-induced liver injury, were reduced by CE administration. Histological evaluation demonstrated that massive cell infiltration after severe injury developed in liver of mice injected with LPS plus D-GalN unless they were pretreated with CE. Apoptotic cells decreased by treatment with CE. Treatment with CE retarded lethal shock induced by an infection with 10(8) CFU Salmonella typhimurium deltaaroA mutant. These results suggest that action of CE is initiated through suppression of LPS-induced TNF production.

Alanine Transaminase↗

PubMed1999

Suppression of lipopolysaccharide-induced tumor necrosis factor-release and liver injury in mice by naringin.

Suppressive effects of naringin on lipopolysaccharide-induced tumor necrosis factor (TNF) release followed by liver injury were investigated. Intraperitoneal (i.p.) treatment with naringin prior to an intravenous (i.v.) challenge of lipopolysaccharide significantly reduced serum TNF levels in a dose-dependent manner and was the most effective when administered 60 min prior to lipopolysaccharide challenge. Treatment with naringin 3 h prior to lipopolysaccharide challenge resulted in complete protection from lipopolysaccharide lethality in D-galactosamine-sensitized mice. Histological estimation revealed that massive cell infiltration followed by severe injury developed in the livers of lipopolysaccharide-treated and D-galactosamine-treated mice unless they had been pretreated with naringin. Appearance of apoptotic cells was also found to decrease by treatment with naringin. Increases in serum levels of aspartate aminotransferase, alanine aminotransferase and creatine kinase, responsible for lipopolysaccharide-induced liver injury, blocked by naringin administration and the levels were nearly to the normal level. These results indicate that action of naringin is mediated through suppression of lipopolysaccharide-induced TNF production.

Alanine Transaminase↗

PubMed1999

Accelerated recovery from cyclophosphamide-induced leukopenia in mice administered a Japanese ethical herbal drug, Hochu-ekki-to.

The effect of a Japanese ethical herbal drug, Hochu-ekki-to (HOT), on recovery from leukopenia induced by cyclophosphamide (CY) was investigated. Daily oral administration of 1000 mg/kg HOT into CY-treated mice significantly prevented decrease of leukocyte numbers in the peripheral blood and accelerated recovery from leukopenia. Ginsenoside Rgl extracted from Ginseng radix, a major herb of HOT, was one of the active ingredients. HOT increased numbers of neutrophils and monocytes in the peripheral blood compared with CY-treated control. Moreover, HOT augmented the resistance against Pseudomonas aeruginosa infection. The number of colony-forming units in the spleen (CFU-S) also increased in HOT-treated mice. The frequencies of IL-3-, GM-CSF- and IFN-gamma-producing cells increased in the spleen, bone marrow, liver and IEL on HOT treatment, and HOT clearly augmented the expressions of IL-3, GM-CSF and IFN-gamma mRNA in the spleen, bone marrow, liver and IEL except IL-3 and IFN-gamma mRNA in the IEL. These results suggest that HOT enhances the production of hematopoietic lymphokines, stimulates the proliferation of hematopoietic progenitor cells and consequently accelerates recovery from leukopenia in CY-treated mice. Additionally, IFN-gamma which HOT-augmented the production may contribute the protective effect against the bacterial infection by activating of phagocyte cells.

Animals↗

PubMed1999

Long-term observation on the changes of somatotopy in the facial nucleus after nerve suture in the cat: morphological studies using retrograde labeling.

To examine the time course of plasticity of the cranial nucleus during axonal regeneration, we followed the topographical reorganization of the cat facial nucleus (FN) up to 24 months after facio-facial nerve suture using retrograde labeling methods. The trunk of the temporal-zygomatico-orbital and both superior and inferior buccolabial branches (defined as main branch) of the facial nerve was cut and sutured again under ketamine hydrochloride anesthesia. At 11-722 days after nerve suture, Fast Blue (FB) and 1,1'-dioctadecyl-3, 3, 3', 3'-tetramethylindocarbocyanine perchlorate (Dil) or horseradish peroxidase (HRP) were injected into the distal part of the sutured main branch and the unoperated posterior auricular branch, respectively. Until about 3 months after suture, the topographical pattern in FN was similar to that observed in normal cats. At about 4 months after suture, FB-labeled motoneurons were distributed not only in the lateral part (including intermediate, dorsal and ventrolateral divisions) but also in the medial subdivision of FN. After a survival period of 18-24 months, FB-labeled neurons were found all over the FN, and their number increased significantly. Interestingly, in the longer survival cases, we noticed that the Dil- or HRP-labeled posterior auricular branch motoneurons also showed a tendency to distribute outside the medial region. The present study showed that somatotopic disorganization starts at around 4 months after suture, which seems to be somewhat slower than that in rats, and continues until a much later postoperative period. Furthermore, we suggested a possibility that the regeneration of one branch may affect the somatotopy of the unoperated nerve branch. These phenomena may contribute to aberrant facial nerve functions such as abnormal associated movement and facial spasm observed after nerve injury.

Amidines↗

PubMed1999

Colony stimulating factor-inducing activity of hesperidin.

To evaluate immunomodulating activities of bioflavones, colony-stimulating factor (CSF)-inducing activity of two dihydroflavones, three flavones and three flavonols were tested. These samples were suspended in saline and injected intraperitoneally (i.p.) into mice at a dose of 1 mg 6 h before bleeding. All compounds carrying the glucosyl-rhamnose moiety showed potent activity. Among them, hesperidin exhibited the strongest activity. Serum CSF production in mice injected with 1 mg hesperidin reached a peak at 9 h later. The activity of hesperidin was dose-dependent at a range of 0.3 to 20 mg/mouse.

Adjuvants, Immunologic↗