Biomedical subjects

S Sakuma

Publications and source records attributed to S Sakuma.

At least 37 records · Page 2Linked to original sources

PubMed2001

FK506 is superior to methotrexate in therapeutic effects on advanced stage of rat adjuvant-induced arthritis.

OBJECTIVE AND DESIGN: The anti-arthritic properties of FK506 were compared with methotrexate (MTX) in established adjuvant-induced arthritis (AIA) in rats. MATERIAL: Female Lewis rats. TREATMENT: Arthritic rats were orally administered with FK506 (1-5.6 mg/kg) and MTX (0.1-1 mg/kg) from days 15-24. METHODS: Arthritis was induced by injection of Mycobacterium tuberculosis into the right hind footpad on day 0. Efficacy was determined on the basis of paw inflammation measured by paw volume and histological change, hyperalgesia and grip strength. Grip strength measurement was employed as an indication of function of paws in arthritic rats. Peripheral white blood cell (WBC) counts and thymus weights were measured, mainly as indicators of toxic side effects. RESULTS: FK506 suppressed paw inflammation and hyperalgesia without toxic effects on WBC and thymus in established AIA. MTX slightly suppressed paw inflammation and hyperalgesia at the highest dose (1 mg/kg). Toxic effects were observed at lower doses than the effective treatment dose with MTX. Grip strength was found to decrease during development of AIA. FK506, but not MTX, treated rats recovered grip strength loss. CONCLUSIONS: The results show that FK506 is more effective and less toxic than MTX in treating established AIA in rats.

Animals↗

PubMed2001

Three-dimensional image display without special eyeglasses: observation of magnetic resonance angiography using the stereoscopic liquid crystal display.

The authors have developed a new stereoscopic liquid crystal display that provides real-time 3-dimensional image viewing without special eyeglasses. The device consists of 3 major parts: (1) an image display composed of a 10.4-inch color liquid crystal plate with a resolution of 640 x 480, (2) an automatic head tracking system, and (3) a special backlight unit for the right and left eyes. Eight radiologists interpreted 60 cases of magnetic resonance angiography (29 cases of cerebrovascular disease and 31 normal cases) to compare film display and the liquid crystal display (ie, pseudo 3-dimensional display and true 3-dimensional display). Using a continuously distributed scale ranging from 0% to 100%, the observers ranked their confidence levels in determining the presence or absence of steno-occlusive disease, aneurysm, and arteriovenous malformation (AVM) and their locations. For statistical evaluation, receiver operating characteristic (ROC) analysis and Brier score were used. For detecting AVM, film reading showed a significantly higher value in the area under the binormal ROC curve (Az) than did pseudo-3-dimensional display (P < .05). Excluding this, however, no significant difference existed in Az values among the 3 viewing methods. Also, there was no significant difference in Brier score between not only the stereoscopic view and nonstereoscopic view groups, but also the senior and junior groups. Subjective estimation of true 3-dimensional display showed that vessels were more distinguishable with less eye fatigue compared with stereoscopic film reading. The stereoscopic liquid crystal display provided almost equal efficacy to film reading; however, the short optimum distance for observation and the low resolution should be improved.

Cerebrovascular Disorders↗

PubMed2001

Colour Doppler sonographic analysis of blood-flow velocity in the human facial artery and changes in masseter muscle thickness during low-level static contraction.

Muscle oedema, which can be seen as a thickness increment by ultrasonography, is important in provoking pain and fatigue during low-level contraction. Although oedema is related to the balance of inflow and outflow of blood, there are no data on the correlation between muscle thickness change and blood-flow. Blood-flow velocities in the facial artery and the muscle thickness changes were measured by colour Doppler ultrasonography in 30 healthy volunteers during 20 min contraction with 10% of maximum force. Thickness and velocity changes both reached a peak in the initial phase of contraction. The initial change of thickness did not correlate with the velocity in the facial artery, while those immediately after exercise showed a high correlation. The velocity changes in the facial artery might depend on both the general response to contraction and local metabolic or mechanical factors in the contracted masseters.

Adolescent↗

PubMed2001

The variation on the mutagenicity of CNP during anaerobic biodegradation.

The mutagenicity of water, including herbicide CNP, and its time-variation during anaerobic biodegradation were studied through Ames assay using strains with or without. S9 mix: TA98, TA 100, YG1021, YG1024, YG1026, and YG1029. The bacteria, for the anaerobic biodegradation, was obtained from a paddy field, and preincubated for a month. The CNP was decomposed in an anaerobic culture inoculated with the bacteria, and finally yielded CNP-amino as one of the CNP metabolites. About 16% of the initial CNP was transformed into CNP-amino by the 14th day. The mutagenicities to TA98. YG1024, and YG1029 strains with S9 mix increased with cultivating time, the latter two showed the strongest sensitivity to CNP-amino. The contribution of CNP to the mutagenicity decreased as the chemical decomposed, while the contribution of CNP-amino increased. However, the increased mutagenicity was not limited to the contribution of CNP-amino. but also to the contribution of other metabolites. The contributions of other CNP metabolites were 67% of total mutagenicity to the TA98 strain and 30% to the YG1029 strain. These unknown mutagenic metabolites were the indirect frameshift mutagens which did not have nitro- and amino-substituents, and the indirect base-pair mutagens which might possibly have some amino-substituents.

Anaerobiosis↗

PubMed2001

Effects of FK506 and other immunosuppressive anti-rheumatic agents on T cell activation mediated IL-6 and IgM production in vitro.

The objective of this study was to investigate the therapeutic potential of FK506 and other immunosuppressive agents for the treatment of rheumatoid arthritis (RA), focusing on the effects on in vitro IL-6 production and IL-6-mediated immune response. We employed an in vitro model producing IL-6 via T cell activation in human PBMC, based on the hypothesis that T cells play a central role in the pathogenesis of RA. FK506 potently inhibited IL-6 production from PBMC stimulated with anti-CD3 and anti-CD28 monoclonal antibody (anti-CD3/CD28). Cyclosporin A (CsA) also inhibited the anti-CD3/CD28 induced IL-6 production but was about 100 times less potent than FK506. Dexamethasone (DEX) inhibited both anti-CD3/CD28 and LPS induced IL-6 production at almost the same concentration. Methotrexate (MTX) did not affect cytokine production. Anti-CD3/CD28 stimulated PBMC culture supernatants were found to enhance IgM production in SKW6.4 cells. The effects of anti-CD3/CD28 stimulated culture supernatants in the presence of agents on IgM production in SKW6.4 cells were investigated. FK506 and CsA led to suppression of IgM production induced by culture supernatants probably via inhibition of IgM inducible cytokine production from PBMC. DEX profoundly enhanced IgM production, although IL-6 production from PBMC was strongly inhibited by the agent. MTX decreased IgM production although it has no inhibitory effect on IL-6 production. The present study suggests that FK506 is the most effective among the four agents for the suppression of IL-6 production and IL-6-mediated autoantibody production in T cell activation related autoimmune diseases such as RA.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Tacrolimus suppressed the production of cytokines involved in atopic dermatitis by direct stimulation of human PBMC system. (Comparison with steroids).

Tacrolimus (FK506) ointment showed remarkable efficacy against atopic dermatitis in animal models and clinical trials. The suppressive effect of tacrolimus on the production of the cytokines involved in atopic dermatitis (IL-2, IL-3, IL-4, IL-5, IFN-gamma and GM-CSF) from human peripheral blood mononuclear cells (PBMC) was investigated. We constructed a new cytokine production system in which T cells are activated by direct stimulation in vitro with anti-CD3/CD2 or anti-CD3/CD28 antibody combination. Tacrolimus inhibited the production of these cytokines by both stimulations. In a comparative study with steroids (alclometasone dipropionate and betamethason valerate) in anti-CD3/CD2 system, tacrolimus and both steroids inhibited Th1 cytokines (IL-2, IFN-gamma), Th2 cytokines (IL-4, IL-5) and IL-3, GM-CSF (produced by both Th1 and Th2). The suppressive effect of tacrolimus on cytokine production was stronger than that of alclometasone dipropionate and equal to or stronger than that of betamethason valerate. The effective dose of tacrolimus (IC50, 0.02-0.11 ng/ml) is almost the same as for Th1 and Th2 cytokines, and 1 ng/ml of tacrolimus suppressed all cytokines completely. These results suggest that tacrolimus suppresses the allergic cytokines from T cells, and that tacrolimus ointment is effective against atopic dermatitis through the inhibition of cytokine production.

Betamethasone↗

PubMed2001

Glypican-2 binds to midkine: the role of glypican-2 in neuronal cell adhesion and neurite outgrowth.

Cell-surface heparan sulfate proteoglycans participate in molecular events that regulate cell adhesion, migration, and proliferation. The present study was performed to elucidate whether glypican-2 plays a role in interactions of neurons with midkine (MK), a heparin-binding neuroregulatory factor. MK bound to heparan sulfate chains of glypican-2 in a manner similar to syndecan-3. Microbeads coated with MK or poly-L-lysine induced clustering of glypican-2 as well as syndecan-3. Substratum-bound MK or poly-L-lysine induced cell adhesion of N2a neuroblastoma cells, while only MK promoted neurite outgrowth of these cells. Ligation of cell-surface glypican-2 with MK or an antibody against epitope-tagged glypican-2 induced cell adhesion and promoted neurite outgrowth. These results verified that cell-surface glypican-2 bound to MK and suggested that MK-glypican-2 interactions participate in neuronal cell migration and neurite outgrowth. In addition, we observed different localization of epitope-tagged glypican-2 and syndecan-3 on the surface of N2a cells; the result suggested that they may play different roles in MK-mediated neural function.

Animals↗

PubMed2001

Immunohistochemical analysis of macrophages and myofibroblasts appearing in hepatic and renal fibrosis of dogs.

Some peptide growth factors produced by macrophages play a role in fibrosis following tissue injury, through the induction of myofibroblasts. In the present study, the appearance of macrophages and myofibroblast development in hepatic and renal fibrosis was determined by immunohistochemical analysis of tissue from 15 dogs. The hepatic and renal fibrosis was classified as grade I, II or III, depending on the extent (percentage) of fibrotic areas per unit area measured by morphometry with Azan-stained sections. The presence of alpha-smooth muscle actin-immunolabelled myofibroblasts was directly related to advancing grade of both hepatic and renal fibrosis. Lysozyme-immunolabelled macrophages also increased in number with increasing grade of hepatic and renal fibrosis. These findings indicate that myofibroblasts and lysozyme-positive macrophages may contribute to progressive fibrosis in canine liver and kidney disease. Interestingly, the number of macrophages recognized by AM-3K, a newly generated monoclonal antibody capable of labelling exuded macrophages and resident tissue macrophages in dogs, fell significantly in grades II and III of renal fibrosis. By contrast, in hepatic fibrosis there were no marked differences in the number of AM-3K-positive macrophages between grades. These findings suggest that there are functional differences between lysozyme- and AM-3K-positive macrophages.

Actins↗

PubMed2001

Effects of lipopolysaccharide on a macrophage-like cell line (HS-P) from a rat histiocytic sarcoma.

Lipopolysaccharide (LPS) is a major modulator of macrophage functions. To characterize a newly established rat histiocytic sarcoma-derived cell line (HS-P), immunophenotypic changes and cellular growth responses of HS-P cells exposed to LPS were investigated and compared with those of MT-9 cells isolated from a rat malignant fibrous histiocytoma. MT-9 cells have somewhat histiocytic features, because occasional cells react to rat macrophage-specific antibodies. Addition of LPS to cultured HS-P cells increased the numbers of cells immunopositive to ED1 (rat macrophage-specific antibody) and ED2 (rat histiocyte-specific antibody) and stimulated the phagocytosis of latex beads, whereas LPS-treated MT-9 cells did not show such immunophenotypic changes. LPS-treated HS-P cells showed enhanced immunolabelling of alpha-smooth muscle actin, suggesting a possible modulation of macrophages towards myofibroblastic cells. To evaluate cellular growth after the addition of LPS or fetal bovine serum, DNA synthesis was examined by measuring tritiated thymidine incorporation, and the mRNA expression of c- jun and c- myc (immediate early genes in the cell cycle) was examined by Northern blot analysis. In HS-P cells, the addition of serum greatly increased DNA synthesis and induced high expression of c- jun and c- myc; in contrast, LPS markedly depressed DNA synthesis and reduced the expression of c- jun and c- myc. HS-P cells were more sensitive than MT-9 cells to the growth-promoting effect of serum and the growth-inhibiting effect of LPS. The study demonstrated that HS-P cells are highly LPS-responsive, indicating that they would be useful for studies of macrophage functions.

Animals↗

PubMed2001

The effects of fatty acyl CoA esters on the formation of prostaglandin and arachidonoyl-CoA formed from arachidonic acid in rabbit kidney medulla microsomes.

Under physiological conditions, small amounts of free arachidonic acid (AA) are released from membrane phospholipids, and cyclooxygenase (COX) and acyl CoA synthetase (ACS) competitively act on this fatty acid to form prostaglandins (PGs) and arachidonoyl-CoA (AA-CoA). We have previously shown that palmitoyl-CoA (PA-CoA) shifts AA away from the COX pathway into the ACS pathway in rabbit kidney medulla at a low concentration of AA (5 microM, close to the physiological concentration of substrate). In the present study, we investigated the effects of stearoyl (SA)-, oleoyl (OA)- and linoleoyl (LA)- CoAs on the formation of PG and AA-CoA from 5microM AA in rabbit kidney medulla microsomes. The kidney medulla microsomes were incubated with 5microM [(14)C]-AA in 0.1 M-Tris/HCl buffer (pH 8.0) containing cofactors of COX (reduced glutathione and hydroquinone) and cofactors of ACS (ATP, MgCl(2)and CoA). After incubation, PG (as total PGs), AA-CoA and residual AA were separated by selective extraction using petroleum ether and ethyl acetate. SA- and OA-CoAs increased AA-CoA formation with a reduction of PG formation, as well as PA-CoA. On the other hand, LA-CoA decreased formation of both PG and AA-CoA. These results suggest that fatty acyl CoA esters can be regulators of PG and AA-CoA formation in kidney medulla under physiological conditions.

Acyl Coenzyme A↗

PubMed2001

Blood flow in and around the masseter muscle: normal and pathologic features demonstrated by color Doppler sonography.

OBJECTIVE: The purpose of this study was to clarify the normal findings of arteries in and around the masseter muscle and to present their pathologic changes with the use of color Doppler sonography. STUDY DESIGN: The vascular appearances were examined for the 4 main arteries feeding the masseter muscle in healthy volunteers (n = 38) and patients with inflammation (n = 5) and intramuscular hemangioma (n = 3). The features of these arteries were investigated together with the flow diameter, flow velocities, and arterial resistances. The symmetry indices were also calculated to assess the pathologic changes. RESULTS: The detection rates of the branch from the transverse facial artery, the masseter artery, and the branch from the maxillary or external carotid artery were 98.7%, 21.1%, and 84.2% in healthy volunteers, respectively. The facial artery that feeds the muscle from the inferior part represented 2 patterns according to anatomic variant: the masseteric branch (22.4%) and the main trunk itself (77.6%). The means of the flow diameter, maximum and minimum velocities, resistive index, and pulsatility index in healthy subjects were 1.8 mm, 24.6 cm/s, 5.1 cm/s, 0.80, and 2.51, respectively. In most of the patients with symptoms, the symmetry indices of all measurement values increased in comparison with those of healthy volunteers. CONCLUSION: Color Doppler sonography is useful in describing the arteries in and around the masseter muscle and has the potential of being used to depict the pathologic changes.

Adult↗

PubMed2001

Atopic dermatitis-like skin lesions induced by topical application of mite antigens in NC/Nga mice.

BACKGROUND: Atopic dermatitis (AD) is a chronic relapsing inflammation usually observed in patients with an individual or a familial history of atopic diseases, precipitated by environmental factors including mite antigens (Ag). However, the exact etiology of AD is unclear. To further explore the pathogenesis and treatment of AD, a suitable animal model is necessary. In this study, we developed a new animal model of AD induced by mite Ag in NC/Nga mice. METHODS: We injected the extracts of mite Ag intradermally at the ventral side of the ear of SPF NC/Nga mice on days 0, 2, 4, 7, 9, 11, 14 and 16, and measured the clinical symptoms and the ear thickness. On day 18, we collected blood and submandibular lymph nodes (LN) of the immunized ear to perform a histochemical analysis, and to measure the plasma immunoglobulins and cytokines. RESULTS: The NC/Nga mice immunized with mite Ag suffered from AD-like skin lesions including erythema followed by edema, excoriation and scaling. The histological and immunohistochemical examinations of the affected skin showed epidermal hyperplasia with hyperkeratosis, severe infiltration of CD4+ T lymphocytes, eosinophils and macrophages, and degranulation of mast cells. The total plasma IgE level was markedly elevated in mite Ag-treated mice. LN cells of mice immunized with mite Ag synthesized IgE in an Ag-dependent manner and secreted interleukin-4 (IL-4) and IL-5 but not interferon-gamma. CONCLUSIONS: NC/Nga mice treated with mite Ag manifest clinical and immunological aspects similar to patients with AD, suggesting that this model is suitable for exploring the pathogenesis of human AD.

Allergens↗

PubMed2001

Characterization of Ascaris-induced biphasic skin allergic reaction model in mice: possible roles of mast cells in early-phase and CD4-positive T cells in late-phase reactions.

We established an Ascaris-induced biphasic skin allergic reaction in mice. In the early-phase reaction (EPR), mast cell degranulation was observed, and tranilast inhibited ear edema. In mast-cell-deficient mice (WBB6F(1)-W/W(V) mice), ear edema in the EPR disappeared, whereas that in the late-phase reaction (LPR) remained. Eosinophils increased, and CD4-positive T cells tended to increase in the LPR. Anti-CD4 antibody, anti-IL-4 antibody and anti-IL-5 antibody all inhibited ear edema and had a tendency to inhibit eosinophil infiltration in the LPR. These data suggest that the EPR is induced by histamine released from mast cells, whereas the LPR is induced by IL-4 and IL-5 produced from CD4-positive T cells.

Animals↗

PubMed2001

Malignant fibrous histiocytoma (MFH) cells and macrophages/histiocytes have a common antigen recognized by a monoclonal antibody risen against a rat MFH-derived cloned cell line.

A monoclonal antibody (B9) was generated by using a rat malignant fibrous histiocytoma (MFH)-derived cloned cell line (MT-8) as the immunogen. Immunohistochemically, B9 reacted specifically with a cytoplasmic antigen of MT-8 cells. Furthermore, B9 immunolabeled another MFH-derived cloned cells (MT-9) and histiocytic sarcoma cells, as well as macrophages/histiocytes in normal and diseased tissues of rats. These findings suggest the presence of a common antigen recognized by B9 between MFH cells and macrophages/histiocytes. This suggests that MFH cells may express histiocytic nature.

Animals↗

PubMed2000

N-ethylmaleimide inhibits xanthine oxidase activity with no detectable change in xanthine dehydrogenase activity in rabbit liver.

The effect of an alkylating agent, N-ethylmaleimide (NEM), on the activities of xanthine oxidase (XO) and xanthine dehydrogenase (XD) in the presence and absence of Cu2+ or trypsin in the cytosolic fraction from rabbit liver was examined. At concentrations ranging from 0.25 to 2.0 microM, allopurinol, which is generally considered to be a XO inhibitor, suppressed the XD activity (41.5-93.4% inhibition) in addition to the XO activity (28.6-88.4% inhibition) under basal conditions, without the addition of Cu2+ or trypsin. In contrast, NEM (100-400 microM) inhibited the XO activity (35.7-85.7% inhibition) without affecting the XD activity. Also, NEM inhibited the Cu2+- and trypsin-induced XO activities, but did not affect the XD activity at the same concentration range. These results demonstrate that NEM can be a selective inhibitor of XO activity in rabbit liver.

Allopurinol↗

PubMed2000

Asymmetric conjugate 1,4-addition of arylboronic acids to alpha, beta-unsaturated esters catalyzed by Rhodium(I)/(S)-binap

Arylboronic acids underwent the conjugate 1,4-addition to alpha, beta-unsaturated esters to give beta-aryl esters in high yields in the presence of a rhodium(I) catalyst. The addition of arylboronic acids to isopropyl crotonate resulted in high yields and high enantioselectivity exceeding 90% ee in the presence of 3 mol % of Rh(acac)(C(2)H(4))(2) and (S)-binap at 100 degrees C. The rhodium/(S)-binap complex provided (R)-3-phenylbutanoate in the addition of phenylboronic acid to benzyl crotonate. The effects on the enantioselectivity of chiral phosphine ligands, rhodium precursors, and substituents on alpha,beta-unsaturated esters are discussed, as well as the mechanistic aspect of the catalytic cycle.

Journal Article↗

PubMed2000

FK506 suppresses neutrophil chemoattractant production by peripheral blood mononuclear cells.

To understand the mechanism of action of FK506 (Tacrolimus) on neutrophil chemotaxis, we examined its effect on human neutrophil chemotaxis and neutrophil chemoattractant production by peripheral blood mononuclear cells. FK506 and cyclosporin A had no direct suppressive effect on neutrophil chemotaxis induced by interleukin-8, leukotriene B(4), complement 5a (C5a), zymosan-activated serum and formyl-Met-Leu-Phe (fMLP). FK506 and cyclosporin A only slightly suppressed the chemotactic activity of platelet-activating factor (PAF). Dexamethasone did not inhibit the chemotactic activity of any chemoattractant. The supernatant of peripheral blood mononuclear cells stimulated with anti-CD3 and CD2 antibodies induced neutrophil chemotaxis. FK506 and cyclosporin A suppressed the chemotactic activity of the supernatant in parallel to the suppression of interleukin-8 production by peripheral blood mononuclear cells. Anti-interleukin-8 antibody completely suppressed the chemotactic activity of the supernatant without drugs. These studies indicate that FK506 may exert a beneficial effect on human inflammatory diseases by suppressing neutrophil chemotaxis secondary to inhibition of chemoattractant (for example, interleukin-8) production by leukocytes.

Cells, Cultured↗

PubMed2000

Distribution of nociceptin/orphanin FQ precursor protein and receptor in brain and spinal cord: a study using in situ hybridization and X-gal histochemistry in receptor-deficient mice.

Nociceptin/orphanin FQ (N/OFQ) is an opioid-like heptadecapeptide agonist for the opioid receptor homolog, N/OFQ receptor. To explore the precise distribution of the peptide-receptor system, the authors examined the brain and spinal cord from receptor-deficient mice bearing the targeted mutation (morc(m1)), a lacZ insertional mutation in the N/OFQ receptor gene. Precursor protein N/OFQ (preproN/OFQ) mRNA was detected by using in situ hybridization, and the N/OFQ receptor was detected by using X-gal histochemistry. The N/OFQ receptor reflected by lacZ expression was observed at high levels in the dentate gyrus, lateral septum, subparafascicular thalamic nucleus, medial preoptic area, median preoptic nucleus, ventromedial preoptic nucleus, anterior hypothalamic area, paraventricular hypothalamic nucleus, ventromedial hypothalamic nucleus, auditory brainstem nuclei, pontine dorsal tegmentum, and nucleus of the solitary tract. In situ detection of the N/OFQ receptor mRNA by digoxigenin-labeled riboprobes coupled with tyramide signal amplification in normal and wild-type mice resulted in the regional distribution paralleling the lacZ expression in these regions. PreproN/OFQ mRNA was expressed at high levels in the subparafascicular thalamic nucleus, central gray, central tegmental field, auditory brainstem nuclei, caudal spinal trigeminal nucleus, and spinal dorsal horn. Furthermore, variable levels of expression of the peptide and receptor were seen in distinct sites of the brain and spinal cord. These data indicate a correspondence of the peptide and the receptor in local distribution at limbic, hypothalamic, and brainstem sites. Together with concurrent physiologic and behavioral studies in mutant mice, the results suggest functional roles for the N/OFQ system, including the central regulation of learning and memory, hearing ability, water balance, food intake, and blood pressure.

Animals↗