Anti-inflammatory Effects of Ampelopsis Japonica Root on Contact Dermatitis in Mice / 中国结合医学杂志

OBJECTIVE@#To investigate the anti-inflammatory potential of Ampelopsis japonica on contact dermatitis (CD).@*METHODS@#A total of 38 Balb/c mice were divided into 5 groups by using a random number table: normal mice (n=6), CD model mice (n=8), CD mice treated with 3 or 30 mg/kg of the ethanol extract of A. japonica (EEAJ, n=8) and 7.5 mg/kg dexamethasone treated CD mice (DEX, n=8). CD was induced using topical application of 1-fluoro-2,4-dinitrofluorobenzene in mice. EEAJ and DEX were topically applied to the shaved skin of each mouse for 6 days, and the effects of EEAJ and DEX on skin lesions and color, histopathological abnormalities such as epidermal hyperplasia and immune cell infiltration, and tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) production were investigated. The effects on changes in body weights and spleen/body weight ratio were also investigated.@*RESULTS@#EEAJ at 30 mg/kg significantly prevented scaling, erythema and enlargement of skin weight compared to using carbon dioxide. EEAJ also prevented epithelial hyperplasia and immune cell infiltrations induced by repeated application of DNFB (P<0.01). In addition, EEAJ significantly lowered levels of TNF-α, IL-6 and MCP-1 (P<0.05 or P<0.01). The anti-inflammatory effects of EEAJ were similar to those of DEX.@*CONCLUSION@#A. japonica may be a new therapeutic agent with the potential to reduce or replace corticosteroids and its mechanisms are closely related to regulation of TNF-α production.

Chemokine Receptor CXCR3 in the Spinal Cord Contributes to Chronic Itch in Mice / 神经科学通报·英文版

Recent studies have shown that the chemokine receptor CXCR3 and its ligand CXCL10 in the dorsal root ganglion mediate itch in experimental allergic contact dermatitis (ACD). CXCR3 in the spinal cord also contributes to the maintenance of neuropathic pain. However, whether spinal CXCR3 is involved in acute or chronic itch remains unclear. Here, we report that Cxcr3 mice showed normal scratching in acute itch models but reduced scratching in chronic itch models of dry skin and ACD. In contrast, both formalin-induced acute pain and complete Freund's adjuvant-induced chronic inflammatory pain were reduced in Cxcr3 mice. In addition, the expression of CXCR3 and CXCL10 was increased in the spinal cord in the dry skin model induced by acetone and diethyl ether followed by water (AEW). Intrathecal injection of a CXCR3 antagonist alleviated AEW-induced itch. Furthermore, touch-elicited itch (alloknesis) after compound 48/80 or AEW treatment was suppressed in Cxcr3 mice. Finally, AEW-induced astrocyte activation was inhibited in Cxcr3 mice. Taken together, these data suggest that spinal CXCR3 mediates chronic itch and alloknesis, and targeting CXCR3 may provide effective treatment for chronic pruritus.

Bamboo salt suppresses skin inflammation in mice with 2, 4-dinitrofluorobenzene-induced atopic dermatitis / 中国天然药物

Bamboo salt (BS) is a traditional Korean food, and has been reported to have anti-cancer, anti-inflammatory, and anti-metastatic effects. However, the anti-atopic dermatitis (AD) activity of BS has not been described yet. In the present study, we examined the preventive effect of BS on AD. The effect of oral administration of BS was tested in a 2, 4-dinitrofluorobenzene (DNFB)-induced AD animal model, by histological analysis, enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, caspase-1 assay, and Western blotting analysis. BS administration reduced the total clinical severity and scratching frequencies, compared with the AD group. In the serum of DNFB-induced AD mice, the levels of IgE, histamine, thymic stromal lymphopoietin (TSLP), interleukin (IL)-5, and IL-13 were significantly reduced by BS treatment. BS significantly reduced the protein and mRNA expression of TSLP, IL-6, and tumor necrosis factor-α in the AD skin lesions. BS markedly reduced the infiltration of inflammatory cells. Furthermore, the activation of caspase-1 was reduced by BS in the AD skin lesions. Our results suggested that BS should be considered as a candidate treatment for allergic inflammatory diseases including AD.

Bamboo salt suppresses skin inflammation in mice with 2, 4-dinitrofluorobenzene-induced atopic dermatitis / 中国天然药物

Bamboo salt (BS) is a traditional Korean food, and has been reported to have anti-cancer, anti-inflammatory, and anti-metastatic effects. However, the anti-atopic dermatitis (AD) activity of BS has not been described yet. In the present study, we examined the preventive effect of BS on AD. The effect of oral administration of BS was tested in a 2, 4-dinitrofluorobenzene (DNFB)-induced AD animal model, by histological analysis, enzyme-linked immunosorbent assay, reverse transcription-polymerase chain reaction, caspase-1 assay, and Western blotting analysis. BS administration reduced the total clinical severity and scratching frequencies, compared with the AD group. In the serum of DNFB-induced AD mice, the levels of IgE, histamine, thymic stromal lymphopoietin (TSLP), interleukin (IL)-5, and IL-13 were significantly reduced by BS treatment. BS significantly reduced the protein and mRNA expression of TSLP, IL-6, and tumor necrosis factor-α in the AD skin lesions. BS markedly reduced the infiltration of inflammatory cells. Furthermore, the activation of caspase-1 was reduced by BS in the AD skin lesions. Our results suggested that BS should be considered as a candidate treatment for allergic inflammatory diseases including AD.

Aryl Hydrocarbon Receptor Ligands Indoxyl 3-sulfate and Indole-3-carbinol Inhibit FMS-like Tyrosine Kinase 3 Ligand-induced Bone Marrow-derived plasmacytoid Dendritic Cell Differentiation

Aryl hydrocarbon receptor (AhR) regulates both innate and adaptive immune responses by sensing a variety of small synthetic and natural chemicals, which act as its ligands. AhR, which is expressed in dendritic cells (DCs), regulates the differentiation of DCs. However, effects of AhR on the differentiation of DCs are variable due to the heterogeneity of DCs in cell surface marker expression, anatomical location, and functional responses. The plasmacytoid DCs (pDCs), one of DC subsets, not only induce innate as well as adaptive immune responses by secreting type I interferons and pro-inflammatory cytokines, but also induce IL-10 producing regulatory T cell or anergy or deletion of antigen-specific T cells. We showed here that AhR ligands indoxyl 3-sulfate (I3S) and indole-3-carbinol (I3C) inhibited the development of pDCs derived from bone marrow (BM) precursors induced by FMS-like tyrosine kinase 3 ligand (Flt3L). I3S and I3C downregulated the expression of signal transducer and activator of transcription 3 (STAT3) and E2-2 (Tcf4). In mice orally treated with I3S and I3C, oral tolerance to dinitrofluorobenzene was impaired and the proportion of CD11c⁺B220⁺ cells in mesenteric lymph nodes was reduced. These data demonstrate that AhR negatively regulates the development of pDCs from BM precursors induced by Flt3L, probably via repressing the expression of STAT3.

Development and use a novel combined in-vivo and in-vitro assay for anti-inflammatory and immunosuppressive agents

Contact hypersensitivity [CHS] mouse model induced by 2, 4-dinitrofluorobenzene [DNFB] is thought to be a T helper 1 [Th1]-dominant response and used for investigating anti-inflammatory and immunosuppressive agents. However, it is hardly used for screening large-scale drugs because of the large number of animals and complex mechanisms involved in-vivo. In this study, we focused on whether T lymphocytes from CHS mouse model could maintain the state of immune response in-vitro and explored a suitable time for drugs screening. The results showed that CD4[+] T cells of CHS mice were higher compared with those in normal group. The expression of T-bet and GATA3 showed a Th1 shift and the levels of interleukin [IL]-2 and IL-4 also showed similar trend. Furthermore, IL-6 produced by T lymphocytes from CHS mice had a high level too. Then, we detected the effects of dexamethasone [DEX], cyclosporine A [CsA] and mycophenolate mofetil [MMF] on T lymphocytes in-vitro, and the data displayed that these immunosuppressive drugs could all inhibit the proliferation of T lymphocytes significantly. These findings suggested that T lymphocytes from CHS mice could mimic a similar immune response in-vitro, and it's also a suitable method for screening anti-inflammatory and immunosuppressive agents

Effects of mustard seed on 2, 4-dinitrofluorobenzene-induced allergic contact dermatitis in BALB/c mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the therapeutic effect of mustard seed on allergic contact dermatitis (ACD) in mice and explore the mechanism.</p><p><b>METHODS</b>Eighteen BALB/c mice were randomly divided into normal control group, model group and mustard seed group. The mice in the normal control group and model group were fed with normal chow, and those in mustard seed group were given 5% mustard seed mixed in the chow. Three weeks later, ACD was induced on the ear using 2, 4-dinitrofluorobenzene. After 24 h, the swelling of the ear was examined, and the rats were sacrificed to collect the ear tissue ears and blood for histopathological and immunohistochemical examinations, RT-PCR and enzyme-linked immunosorbent assay.</p><p><b>RESULTS</b>In mice with ACD, feeding with mustard seeds significantly lessened the ear swelling, improved the tissue histopathology, lowered the number of infiltrating Langerhans cells, and reduced the expressions of IL-1β, TNF-α and IL-6 mRNA in the ear, but did not cause significant changes in serum levels of IL-4, IFN-γ and IL-17.</p><p><b>CONCLUSION</b>Mustard seed inhibits ACD in mice possibly by suppressing the expressions of IL-1β, TNF-α and IL-6 mRNA and inhibiting Langerhans cell migration in the epidermis.</p>

The Effect of ER:YAG Laser & ER,CR:YSGG Laser on the Tissue of the Inflammation-Induced Mouse

The Production and Functions of Reactive Oxygen Species in Mouse Bone Marrow-derived Dendritic Cells by Various Haptens and Irritants / 대한피부과학회지

BACKGROUND: Various allergens and irritants induced the production of reactive oxygen species (ROS) in the well-established mouse dendritic cell (DC) line XS106 and this production of ROS was inhibited by antioxidants. OBJECTIVE: To investigate the production and functions of ROS in mouse bone marrow-derived DCs (BM-DCs) by various haptens and irritants, we examined the production of ROS, the expression of surface molecules, and the production of interleukin-12 (IL-12) in mouse BM-DCs. METHODS: Six to eight-week-old female C57/BL6 mice were used in this study. Mouse BM-DCs were co-cultured with DNFB, DNCB, TNBS, hydroquinone, NiSO4, CoCl2, MnCl2, thimerosal, SDS, and BKC. The production of ROS and the expression of surface molecules (CD40, CD80, CD86, and MHC-II) were measured by flow cytometry in chemical-treated mouse BM-DCs. In addition, the cells were pretreated with antioxidants to determine whether the production of ROS can be inhibited. The production of IL-12 was also measured in DNCB and SDS-treated mouse BM-DCs using ELISA. Results: The production of ROS in mouse BM-DCs was induced by various allergens, including DNFB, DNCB, TNBS, hydroquinone, MnCl2 and irritants like SDS, BKC. The expression of surface molecules was induced by various chemicals and NiSO4 was the most potent inducer of surface molecules in mouse BM-DCs. The production of ROS in DNCB and SDS-treated mouse BM-DCs was partially inhibited by diphenylene iodonium, but not by rotenone, vitamin E, allopurinol, glutathione. The production of IL-12 was not detected in DNCB and SDS-treated mouse BM-DCs. CONCLUSION: The production of ROS was induced in mouse BM-DCs by various allergens and irritants. The expression of surface molecules was also induced by various chemicals. The production of ROS was partially inhibited by DPI. The production of IL-12 was not detected.

Effect of etoposide on allergic contact dermatitis induced by dinitrofluorobenzene and its action mechanism in mice / 药学学报

This study is to observe the inhibition of etoposide on allergic contact dermatitis (ACD) and explore its possible mechanism of action. Dinitrofluorobenzene was used to induce the allergic contact dermatitis in mouse ear. Three groups of animals were orally administrated with different doses of VP-16 (5, 10, and 20 mg x kg(-1)), separately, for six days. The degree of skin inflammatory reaction was observed by optical microscope. Expression of intercellular adhesion molecule (ICAM-1) was detected by immunohistochemical staining. Radioimmunoassay was applied to measure the serum level of tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10). VP-16 significantly decreased inflammatory cell infiltration and the degree of infiltration reaction, and decreased the level of TNF-a in serum and the expression of ICAM-l in skin. VP-16 can significantly inhibit allergic contact dermatitis induced by DNFB. This therapeutic effect of VP-16 on murine ACD may be due to inhibiting expression of some cytokines.

The Effects of High-dose Vitamin C Administration on the Cell-mediated Immune Response in Mice

BACKGROUND: Vitamin C is an essential nutrient, taken as a daily supplement by many people. Recently, high-dose vitamin C is considered as a therapeutic regimen in some clinical situations. Until now, few studies have been done with the effects of high-dose vitamin C on the immune response. METHODS: In this experiment, the effects of high-dose vitamin C on cell-mediated immune response in immunologically competent mice were evaluated. After intraperitoneal injection of 2.5, 5, or 10 mg/day of vitamin C for 10 days, delayed type hypersensitivity (DTH) was provoked against DNFB in the pinnae as a model for cell-mediated immune response. Severity of DTH reaction was evaluated as the thickness of pinnae, and the vitamin C levels were measured in the serum, liver, kidney, lung, pinnae, and splenocytes. RESULTS: After challenge, the thickness increased at its peak on the 2(nd) day in all groups. On the first day, the pinnae were thicker in the injected groups than in the control. On the contrary, the increment of the pinnae thickness was attenuated and the number of cells infiltrated in the site of DTH decreased proportionately to the amount of vitamin C administered from the second day on. With vitamin C exogenously given, the serum level peaked at 30 min after injection, and returned abruptly to its basal level without accumulation. However, it accumulated in the liver, kidney, and especially in the pinnae inflamed and splenopcytes, proportionately to the amount administered. CONCLUSION: Based on these results, it is suggested that, in one hand, exogenously administered high-dose vitamin C accumulated in the splenocytes and presumably changed the function of them resulting in the augmented cell-mediated immune response, as was revealed in the first day of DTH reaction. On the other hand, it seems likely that the vitamin C also showed anti-inflammatory effects.

The Suppressive Effect of Evening Primrose Oil on Murine Contact Sensitivity

BACKGROUND: Evening primrose oil(EPO) is a rich source of cis-linoleic acid and gammalinolenic acid(GLA) and has been used as a therapeutic agent in various skin diseases such as atopic dermatitis. OBJECTIVE: The purpose of this study was to evaluate the suppressive effect of EPO on murine contact sensitivity. METHODS: BALB/c mice were divided into 3 groups, positive control, experimental and negative control groups: the positive control group represents a group of mice which were sensitized and challenged with DNFB, the experimental group represents EPO-pretreated positive control group and the negative control group represents a group of mice which were challenged only. The changes of ear thickness were measured, and H & E staining and immunohistochemical staining for ICAM-1 expression of ear skin were performed to evaluate the histological changes of each group. RESULTS: The Pretreatment of mice with EPO resulted in suppression of contact sensitivity by more than 82%. On H & E staining, only a mild inflammatory reaction was observed in the dermis. Also ICAM-1 expression of keratinocytes, the intensity of the staining was significantly decreased in the experimental group compared with positive group. CONCLUSIONS: Our study indicates that EPO was able to suppress the induction of contact sensitivity.

The change of langerhans cells,la+kerationocytes and thy-1+dendritic epidermal cell in allergic contact dermatitis and irritant contact dermatitis / 대한피부과학회지

BACKGROUND: Langerhans cells (LC), keratinocytes and Thy-1+ dendritic epidermal cells(DEC) are epidermal cells which are known to have important roles in inflammatory or immunologic skin disorders. Allergic contact dermatitis(ACD) is a prototype of a delayed hypersensitive reaction in which LC, keratinocytes and T lymphocytes play an important role. The role of LC in ACD is well known, but the role of Thy-1+ DEC is not yet fully revealed. Futhermore, the mechanism of irritant contact dermatitis(ICD) is not known and more study is required on the interaction between these epidermal cells in ICD. OBJECTIVE: The aim of this study is to observe the changes of these cells in ACD and ICD and to discuss their possible roles in the disease precess. MEHTODS: We evoked ACD with DNFB and ICD with croton oil in BALB/c mice and observed the morphologic changes of LC, Ia+ keratinocytes, and Thy-1+ DEC by immunoperoxidase staining when the inflammation was at its peak and at the resolution state. RESULTS: 1. In the control group, LC were evenly distributed and their average number was 1147+/-132/mm*. Thy-1+ DEC were slightly bigger than LC and showed uneven distribution. The average number of Thy-1+ DEC was 57+/-69/mm* Ia+ keratinocytes did not appeared. 2. On the 1st day of DNFB challenge, the number of LC was significantly decreased and their size and dendritic processes were increased when compared to those of the control group. Most of the keratinocytes showed Ia antigen expression on their surfaces. 3. On the 12th day of DNFB challenge, no significant changes in the number and morphologyof LC were noted when compared to the cotrol group, Ia+ keratinocytes were not observed. 4. there were no significant changes in the number and morphology of Thy-1+ DEC in ACD on the 1st and 12th day after DNFB challenge. 5. On the 2nd day after croton oil application, the number of LC was significantly decreased but the morphology not significantly changed. Ia+ keratinocytes were not observed. 6. On the 20th day after croton oil application, the number of LC was significantly increased but the morphology was not significantly changed. Ia+ keratinocytes were not observed. 7. There were no significant changes in th number and morphology of Thy-1+ DEC in ICD on the 2nd and 20th day after application of croton oil. Ia+ keratinocytes were not observed. CONCLUSION: In can be deduced that the LC have important roles in the mechanisms of both ACD and ICD reactions. Ia+ keratinocytes have an important role mainlyin the inflammatory precess of ACD. In addition, since the changes of the number of Langerhans cells in ACD and ICD showed different time courses and Ia+ keratinocytes appeared only in ACD, we hypothesized that different pathways of inflammation exist in ACD and ICD, and different cytokines may be responsible. It is probable that Thy-1+ DEC does not have any significant role in the inflammatory process of both ACD and ICD.

Effect of Bovine Aqueous Humor on Prodution of IL-2 and IL-6, and Other Parameters of Immunoeompetency in Mice

The injection of antigen into the anterior chamber of the eye results in a unusual pattern of systemic immune responses termed anterior chamber associated immune deviation(ACAID). This study was done to investigate the in vitro effect of bovine aqueous humor(BAR) on the proliferation response of murine spleen and thymus to mitogens, to determine in vivo effects of BAR on delayed-type hypersensitivity and hemagglutinin response to sheep red blood cells, and to examine contact hypersensitivity to dinitrofluorobenzene(DNFB). Also, the effect on in vivo exposure to BAH on the production of IL-2 and IL-6 of murine lymphocyte was investigated. As a result, various concentration of BAR inhibited or enhanced the proliferation response of mouse splenocytes to mitogens. BAR injection significantly enhanced 'Arthus reaction to SRBC, but failed to change DTR reaction to SRBC. Interestingly, however, BAR profoundly inhibited contact hypersensitivity to DNFB and HA response. BAR inhibited both IL-2 and IL-6 production of murine spleen and thymus cells. Taken together, these results suggest that BAR contains soluble factor(s) that can suppress or enhance immune response, depending on experimental conditions and that immunomodulatory activity of BAR is not species-specific.

High Doses of UVA Suppress Contact Hypersensitivity

Contact hypersensitivity (CH) responsiveness to 24-dinitro-l-fluorobenzene(DNFB)is depressed in mice sensitized through unexposed skin sites after exposure to high dose of ultraviolet B radiation(UVB). Exposure of mice to ultraviolet A(UVA) radiation in combination with 8-methoxypsoralen(8-MOP) also results in a systemic suppression of CH. Our study was designed to determine whether a high dose of UVA radiation alone can induce a systemic suppression of CH, and if so, which phase of CH response is influenced by UVA radiation. Relatively large doses of UVA(400, 600, 800J/cm²) induced significant systemic suppression of CH when DNFB was applied to UVA-unirradiated abdominal skin. The duration of the rest period after UVA exposure did not cause any significant change in systemic suppresion of CH. Functional analyses showed that lymph node cells(LNCs) obtained from donors that were sensitized on the unirradiated skin site with DNFB 5 days after UVA treatment transferred normal ear-swelling responsiveness to non-primed recipients, thus implying that high doses of UVA can induce systemic suppression which is not affected in the induction phase of CH but affected in the elicitation phase of CH. UVA irradiation de-creased Langerhans cell(LC) numbers significantly with a dose of 100J/cm² or greater. LNCs obtained from donors that were sensitized on the irradiated skin site with DNFB 5 days after UVA treatment did not transfer normal ear-swelling responsiveness to non-primed recipients. This phenomenon may be related to the decreased number of LC after UV treatment. To look for possible mediators impairing the elicitation phase of the CH reaction, we checked prostaglandin E(PGE) levels in serum after 800J/cm² irradiation. A high dose of UVA did not increase the serum PGE level in mice as much as UVB irradiation, in which a significant increase of PGE may affect CH response.

High Doses of UVA Suppress Contact Hypersensitivity

Contact hypersensitivity (CH) responsiveness to 24-dinitro-l-fluorobenzene(DNFB)is depressed in mice sensitized through unexposed skin sites after exposure to high dose of ultraviolet B radiation(UVB). Exposure of mice to ultraviolet A(UVA) radiation in combination with 8-methoxypsoralen(8-MOP) also results in a systemic suppression of CH. Our study was designed to determine whether a high dose of UVA radiation alone can induce a systemic suppression of CH, and if so, which phase of CH response is influenced by UVA radiation. Relatively large doses of UVA(400, 600, 800J/cm²) induced significant systemic suppression of CH when DNFB was applied to UVA-unirradiated abdominal skin. The duration of the rest period after UVA exposure did not cause any significant change in systemic suppresion of CH. Functional analyses showed that lymph node cells(LNCs) obtained from donors that were sensitized on the unirradiated skin site with DNFB 5 days after UVA treatment transferred normal ear-swelling responsiveness to non-primed recipients, thus implying that high doses of UVA can induce systemic suppression which is not affected in the induction phase of CH but affected in the elicitation phase of CH. UVA irradiation de-creased Langerhans cell(LC) numbers significantly with a dose of 100J/cm² or greater. LNCs obtained from donors that were sensitized on the irradiated skin site with DNFB 5 days after UVA treatment did not transfer normal ear-swelling responsiveness to non-primed recipients. This phenomenon may be related to the decreased number of LC after UV treatment. To look for possible mediators impairing the elicitation phase of the CH reaction, we checked prostaglandin E(PGE) levels in serum after 800J/cm² irradiation. A high dose of UVA did not increase the serum PGE level in mice as much as UVB irradiation, in which a significant increase of PGE may affect CH response.

In vivo and in vitro measurement of cell mediated immunity in Marek's disease: role of reticuloendothelial system.

Dinitrofluorobenzene (DNFB) contact-sensitivity test and leucocyte adherence inhibition (LAI) test were performed in this study as in vivo and in vitro tests to measure the cell-mediated immunity (CMI) in chickens subjected to stimulation of reticuloendothelial (RE) system, depletion of RE system and other experimental groups after being challenged with Marek's disease (MD) virus. It was found that CMI was lower in the birds with depleted RE system and infected control birds, whereas CMI was higher in the birds with activated RE system and vaccinated birds as revealed by DNFB contact-sensitivity test. In cases of LAI test, the number of LAI-positive birds were highest in the chicks with depleted RE system particularly in 3rd and 4th month of age, when the incidence of MD was also maximum.

Effect of extracellular pH and DNFB treatment on the mechanical performance of frog skeletal muscle.

isometric tension and maximum velocity of shortening of frog sartorious and biceps muscles were measured at varying pH and compared with the values obtained for muscles treated with DNFB. Both To and Vmax exhibited increase with increase in pH above neutral pH upto pH 9, and decreased as the pH was decreased up to 5. Muscle treated with DNFB at pH 7 showed about 30% decrement but these too improved at pH 9 to almost 105% and 130% respectively compared to untreated muscle at pH 7. Using the number of short duration tetanic contractions, which reduce To and Vmax by half, as an index for the onset of fatigue, high pH was found to have a positive effect in both normal and DNFB-treated muscle. Thus, the crucial factor for onset of fatigue is not a fall in ATP level but acidification and treatment with high pH Ringer's solution partially annuls the effect of acidosis, arising either naturally or from DNFB treatment. One additional role of creatine kinase activity to that of ATP regeneration is suggested to be the maintenance of neutral pH in the sarcoplasm.

Xantina oxidasa hepática: experiencias con inhibidores / Liver xanthine oxidase: experiences with inhibitors

Los grupos amino de la XOD (Xantina oxidasa) del hígado de rata son inhibidos por reactivos como el benzaldehído y el 2,4-dinitrofluorbenceno. Esta inhibición ocurre más rápidamente a elevados pH y es progresiva e irreveersible. Estos reactivos atacan grupos amino de la XOD, pero no se excluye que haya otros grupos que puedan ser bloqueados. Si se representa la inhibición en función de la unión con el benaldehído o 2,4-dinitrofluorbenceno, se observa que una fracción relativamente pequeña del total de grupos amino de la XOD es más reactiva a esta inhibició y que estos grupos amino se modifican por estos inhibidores. Los estudios de unión del benzaldehído sugieren dos clases de actividad enzimática, presentes en igual proporción, pero difieren en su sensibilidad frente al benzaldehído. Los parámetros cinéticos de la actividad residual de la XOD tratada con benzaldehído se asemejan a los de la enzima nativa, excepto el comprotamiento inhibitorio frente a altas concentraciones de sustrato

Induction of DNCB Oral Tolerance in Mice / 대한피부과학회지

Tolerance to contact hypersensitivity was induced by feeding of different DNCB doses in mice. A total of 40 mice were divided into 4 groups(control group, 6 mg feeding group, 10 mg feeding group, 14 mg feeding group) in experiment I, Degree of tolerance to contact hypersensitivity was rneasured by incremert rate of ear swelling after challenge with DNFB. Experiment 2 was performed in the same method of cxperiment: I with addition of 3 mg DNCB feeding group. The increment ratee were significantly decreased in DNCB feeding groups in experirnent 1 and 2(p<0.0l). But there were no differences statisticalIy between increment rates of DNCB feeding groups.