Inhibitory effect of high dose ascorbic acid on inflammatory edema

The ability of ascorbic acid (AA) as an antioxidant to suppress the inflammatory reaction was investigated. Carrageenan-induced foot pad edema was produced in the right hind foot of anesthetized mice (n=22). Subsequently, Group A (n=11) received 25 mg AA in saline (IP) and Group B, an equal volume of saline. After 2 1/2 hrs the animals were sacrificed and increase in weight of the amputated right paw over the amputated left paw was expressed as percentage edema (PE). The PE in Group A was 43.8±5.9, and in Group B was 59.3±3.9 (p<0.05, unpairedt-test). The same experiment was repeated with the AA administered 10 minutes prior to injury. The change in edema was not statistically significant. It is concluded that high dose AA suppresses edema if given after but not before injury.     

Inhibitory effect of somatostatin on human T lymphocytes proliferation

Somatostatin (SOM) was originally described as a growth hormone release inhibiting factor, but SOM and its specific receptors (SOM-r) have been shown to be expressed on both normal and activated T and B lymphocytes and other immunocompetent cells. In the present study we have demonstrated that SOM strongly inhibits the proliferation of human T lymphocytes when stimulated by PHA, Con A or alloantigens. However, SOM was most effective when the T cells were stimulated by an alloantigen rather than a polyclonal activator such as PHA and ConA. Moreover, SOM strongly inhibited the expression of activation markers such as CD69 and CD25 that are expressed on T lymphocytes during alloantigen stimulation. SOM also inhibited both CD28 and CD2 mediated T cell proliferation. Whereas proliferation of T cells induced by the engagement of CD3 antigen using specific mAbs was only marginally affected. Our results would support the concept that in humans SOM plays a key role in the modulation of T cell activation by interfering with the antigen-independent pathways CD2 and CD28.     

Inhibitory effects of ascorbic acid and folinic acid on chromosome aberrations induced by pyrimethamine in vitro

In this study, the anticlastogenic effects of ascorbic acid and the protective effect of folinic acid against the formation of chromosomal aberrations in humans by pyrimethamine were investigated. Pyrimethamine is a folic acid antagonist used for the treatment of malaria and toxoplasmosis. In this study, 18 different healthy people, who do not drink alcohol and are non-smokers, were chosen as an experimental group; 0.025 mg/ml pyrimethamine was given to the lymphocyte culture, which had been prepared with the peripheral blood taken from this group. After that each of the following doses were given to the same culture: 20, 40, and 80 mM of ascorbic acid and 25, 50, and 100 mM of folinic acid. The results of the cytogenetic evaluation showed that the aberrations due to pyrimethamine in the chromosomes were reduced by ascorbic acid and folinic acid significantly, depending on the given dose.     

The effect of ascorbic acid on the human lymphocyte

Human lymphocytes obtained from normal, healthy subjects were studied for their in vitro responses to ascorbic acid. Ascorbic acid inhibited the incorporation of 3H-uridine as well as the phytohaemagglutin-associated enhancement of 3H-thymidine incorporation.     

The effect of acetylsalicylic acid on the metabolism and transformability of human lymphocytes in vitro

Summary Acetylsalicylic acid inhibits the hexokinase activity of human lymphocytes in vitro. The effect is proportional to the concentration and is readily demonstrable at concentrations greater than 2–3 mMols per liter. In agreement with this, a reduction in the glucose-C¹⁴-decarboxylation rate is seen.This inhibitory effect could be the cause of the observed deterioration of the lymphocyte transformation and C¹⁴-thymidine incorporation in the presence of acetylsalicylic acid. Corresponding to the evident glucose-competitive mechanism of the acetylsalicylates, the inhibition of the thymidine incorporation in stimulated lymphocytes was reversed by increasing the glucose concentration of the culture medium. The results would seem to indicate an immunosuppressive action of acetylsalicylic acid.This investigation was supported by a grant from the Deutsche Forschungsgemeinschaft, Bad Godesberg.     

核心蛋白聚糖对翼状胬肉成纤维细胞增殖的影响

目的: 观察核心蛋白聚糖(DCN)对体外培养人翼状胬肉成纤维细胞(HPF)增殖的影响,并对照观察丝裂霉素C(MMC)对HPF的影响,寻找辅助治疗和预防翼状胬肉复发的新途径。方法: (1)取患者的翼状胬肉体部组织,采用组织块贴壁培养法原代培养HPF。(2)用0.01、0.1、1、5、10 mg/L DCN及 MMC分别作用于体外培养的HPF, 24 h、48 h、72 h后观察2种药物对HPF形态的改变,2种药物不同浓度分别作用12 h、24 h、48 h后 MTT法比较2种药物的作用效果,不同浓度的DCN作用48 h后免疫组织化学染色增殖细胞核抗原(PCNA)法检测细胞生长活性,流式细胞术测定细胞周期时相变化。结果: 10 mg/L DCN或1 mg/LMMC在12 h后均能显著抑制HPF的增殖(P<0.05),呈剂量和时间依赖性。1~10 mg/L DCN 作用48 h使G₀/G₁期细胞百分比上升(P<0.05),5~10 mg/LDCN 作用48 h使G₂/M期和S期百分比(G₂/M%+S%)显著下降(P<0.05),实验组和对照组均未检测到终末期凋亡细胞。1~10 mg/L DCN能浓度依赖性地抑制细胞表达PCNA(P<0.05)。结论: 核心蛋白聚糖能抑制HPF的增殖,阻滞细胞在DNA合成前期。     

The principal phenolic and alcoholic components of wine protect human lymphocytes against hydrogen peroxide- and ionizing radiation-induced DNA damage in vitro

We have tested the hypothesis that the alcoholic and phenolic components of wine are protective against the DNA-damaging and cytotoxic effects of hydrogen peroxide and gamma-radiation in vitro. The components of wine tested were ethanol, glycerol, a mixture of the phenolic compounds catechin and caffeic acid and tartaric acid, all at concentrations that were 2.5 or 10.0% of the concentration in a typical Australian white wine (Riesling). These components were tested individually or combined as a mixture and compared to a white wine stripped of polyphenols, as well as a Hanks balanced salt solution control, which was the diluent for the wine components. The effect of the components was tested in lymphocytes, using the cytokinesis-block micronucleus assay, after 30 min incubation in plasma or whole blood for the hydrogen peroxide or gamma-radiation challenge, respectively. The results obtained showed that ethanol, glycerol, the catechin-caffeic acid mixture, the mixture of all components and the stripped white wine significantly reduced the DNA-damaging effects of hydrogen peroxide and gamma-radiation (P = 0.043-0.001, ANOVA). The strongest protective effect against DNA damage by gamma-irradiation was observed for the catechin-caffeic acid mixture and the mixture of all components (30 and 32% reduction, respectively). These two treatments as well as ethanol produced the strongest protective effects against DNA damage by hydrogen peroxide (24, 25 and 18%, respectively). The protection provided by the mixture did not account for the expected additive protective effects of the individual components. Ethanol was the only component that significantly increased baseline DNA damage rate, however, this effect was negated in the mixture. In conclusion, our results suggest that the main phenolic and alcoholic components of wine can reduce the DNA-damaging effects of two important oxidants, i.e. hydrogen peroxide and ionizing radiation, in this physiologically relevant in vitro system.     

Inhibitory effect of ascorbic acid on human retinal pigment epithelial cell proliferation compared to cytostatic drugs - influence of histamine

Inflammation Research -     

Inhibitory effect of retinoic acid receptor agonists on in vitro chondrogenic differentiation

Anatomical Science International - Retinoic acid (RA), an active metabolite of vitamin A, plays pivotal roles in a wide variety of biological processes, such as body patterning, organ development,...     

Adaptive response to DNA and chromosomal damage induced by X-rays in human blood lymphocytes

Nucleoid sedimentation, single-cell gel electrophoresis (comet assay) and premature chromosome condensation (PCC) technique were utilized to estimate the involvement of DNA strand breaks and chromosomal damage in radio-adaptive response of stimulated human lymphocytes. Conditioning of cells with 0.02 Gy X-rays rendered them more resistant to single- and double-strand DNA breaks produced by 1 Gy challenging treatment as revealed by the sedimentation behaviour of the nucleoids and the comet assay. Nucleoid sedimentation also demonstrated that adaptive reaction towards X-ray-induced DNA damage is favoured in the presence of oxygen. A concomitant decrease in the amount of interphase chromosomal breaks visualized by PCC under the same experimental conditions was observed. Data indicate that adaptation of human lymphocytes to X-rays is tightly linked to the reduced susceptibility towards generation of DNA and chromosomal breaks. It is proposed that the very persistence of DNA strand discontinuities might serve as a triggering signal for the adaptation of human lymphocytes against ionizing radiation exposure.     

In vitro effect of ascorbic acid on infectivity of herpesviruses and paramyxoviruses.

Suspensions of herpes simplex virus types 1 and 2, cytomegalovirus, and parainfluenzavirus type 2 were inactivated within 24 h when treated at 37 degrees C with 1 mg (5.05 mM) of copper-catalyzed sodium ascorbate per ml. The infectivity titer of respiratory syncytial virus was reduced substantially after 24 h but required 48 h for inactivation. Under these conditions, inactivation of these viruses was also successfully achieved with 5.68 mM catalyzed ascorbic acid. Copper (Cu2+), when added with the ascorbate solution at 5 micrograms/ml (0.022 mM), exhibited a catalytic effect on the inactivation of these viruses. The rate of inactivation was affected by the incubation temperature, time of exposure, and the virus concentration. Ascorbate concentrations as high as 10 mg/ml (50.5 mM) demonstrated only a minimum increase in effect on viral inactivation. The loss of infectivity did not alter either the hemagglutination or complement fixation qualities of the antigens.     

Use of radiation induced chromosomal damage in human lymphocytes as a biological dosimeter is questionable

Using dicentric chromosomes and acentric fragments as indicators of radiation sensitivity, a study has been performed on human lymphocyte chromosomes by irradiating peripheral blood cells at G0. Donor-to-donor variation has been noticed regarding radiation sensitivity even when metaphase spreads were scored at the first cell cycle. Thus, it appears that, at the present state, use of chromosomal damage in peripheral blood cell cultures as an effective biological dosimeter for effects of radiation is questionable.     

Susceptibility of peripheral lymphocytes of brain tumour patients to in vitro radiation-induced DNA damage,a preliminary study

OBJECTIVE: The present investigation aimed to study the susceptibility of lymphocytes collected from brain tumour patients to radiation-induced DNA damage under in vitro conditions. METHODS: The peripheral lymphocytes collected from brain tumour patients were exposed to 2-Gy gamma radiation. Susceptibility of lymphocytes to radiation-induced DNA damage and their repair ability was assessed by alkaline comet assay. RESULTS: Lymphocytes of patients with benign and malignant tumour had a significantly higher (p < 0.001) baseline DNA damage compared to lymphocytes from normal subjects. A significant increase (p < 0.001) in DNA damage was observed immediately after irradiation of lymphocytes from healthy subjects and brain tumour patients. However, at 1 h after irradiation the level of DNA damage dropped significantly (p < 0.001) compared to that of immediately after irradiation of respective groups. DISCUSSION: In conclusion, the lymphocytes of brain tumour patients possess a higher level of basal DNA damage and exhibit a higher susceptibility to a clastogenic agent like radiation.     

红车轴草提取物对小鼠T淋巴细胞体外活化的抑制作用

探讨红车轴草提取物(Trifolium pratense Leguminosae extract,TLE)对小鼠T淋巴细胞的体外活化的影响。无菌条件下制备小鼠淋巴细胞悬液;双色荧光抗体染色结合流式细胞术分别分析TLE对小鼠T淋巴细胞在刀豆蛋白A(ConA)或佛波醇酯(PDB)刺激下的体外分化抗原CD69、CD25、CD71表达的影响。终质量浓度为20、30、40 mg/L的TLE对小鼠T淋巴细胞在ConA或PDB刺激下的体外分化抗原CD69、CD25、CD71表达具有明显的抑制作用(P<0.01)。TLE对ConA或PDB刺激的不同时期的小鼠T淋巴细胞的体外活化具有明显的抑制作用。     

Transmission of gamma-ray-induced unstable chromosomal aberrations through successive mitotic divisions in human lymphocytes in vitro

Transmission of unstable chromosomal aberrations through successive mitotic divisions M1-M4 was analysed in 3 Gy gamma-ray-irradiated G0 human lymphocytes in vitro, harvested at 50, 72 and 96 h. Bromodeoxyuridine (BrdU) incorporation and subsequently the fluorescence plus Giemsa (FPG) method allowed the cell cycle status of each cell scored to be ascertained. Higher dicentric frequencies were observed in cells within the same post-irradiation division derived from extended culture times, indicating either a delay in cell cycle progression of aberrant cells or different lymphocyte sub-populations. The yield of complete dicentrics decreased by a factor of two in passing from M1 to M2 and showed further reductions of 26 and 44%, respectively, in moving from M2 to M3 and from M3 to M4. In the case of conventionally stained metaphases, wherein the cell cycle status does not enter the picture, the dicentric frequencies showed a reduction in yield of 39.6% at 72 h and 52.1% at 96 h compared with 50 h, because the cells analysed comprise a mixture of metaphases in different cell cycles. In the FPG stained first division metaphases, 92-100% of dicentrics analysed at 50, 72 and 96 h and in the conventionally stained metaphases, 90-94, 72-84 and 54-80% of dicentrics analysed at 50, 72 and 96 h respectively were complete dicentrics (with fragments). In the M1, M2, M3 and M4 metaphases analysed, 92-100, 50-89, 20-70 and 10-50% of dicentrics, respectively, were complete dicentrics and 55-75, 53-68, 43-57 and 36-50% excess acentrics, respectively, were seen in cells with complete dicentrics. Interindividual variation was observed in cell cycle kinetics, radiation-induced chromosomal aberrations and micronucleus frequencies. A salient feature of the delayed effects was the induction of giant cells and the mirror dicentrics observed in them. The reduction in dicentric frequencies due to either cell cycle delay or cell death in successive generations is aided by the multiplicity of aberrations. Bridge-breakage-fusion (BBF) events mediated by dicentric chromosomes may also be instrumental in the perpetuation of chromosomal instability.     

G-Banding analysis of radiation-induced chromosome damage in lymphocytes of hiroshima A-bomb survivors

Summary The present report describes the G-band analysis of somatic chromosomes in lymphocytes from 63 A-bomb survivors in Hiroshima to determine the type and frequency of radiation-induced chromosome aberrations. (1) The cells with stable-type chromosome aberrations (Cs cells) predominated among the aberrant cells, and showed a dose-dependent increase. All stable chromosome aberrations were classified into nine categories: reciprocal translocations, translocations of complex type, insertions, complex exchanges, peri- and paracentric inversions, terminal and interstitial deletions, and unidentified rearrangements. The frequencies of aberrations were found to increase with increasing dose for all aberration categories. Reciprocal translocations predominate in all dose ranges and among the chromosome aberrations classified. (2) The linear model was fitted to test the dose-response relationship for Cs cell frequencies. Employing a constant neutron RBEs of 10, an estimated linear slope of 15.2%/Sv was obtained for DS86 bone marrow dose with an intercept of 2.9% at dose 0. (3) Statistical analysis of data on 3,370 break sites showed good correlations betweens relative DNA content and the distribution of chromosome breaks involved in translocations, although the involvement of chromosome 1 is significantly higher.     

Inhibitory effect of progesterone on the phytohaemagglutinin- induced transformation of human peripheral lymphocytes.

Effect of sex steroids, progesterone and estradiol-17beta, on transformation of human lymphocytes induced by PHA was investigated. Responses of peripheral lymphocytes from non-pregnant women to PHA was markedly reduced in the presence of progesterone at a concentration of 10(3) or 10(4) ng/ml. Estradiol-17beta, on the other hand, had no effects on the PHA-induced transformation under the present experimental conditions. The immunosuppressive property of progesterone may contribute to depression of maternal cell-mediated immunity against fetus during pregnancy.     

人胚胎干细胞对肝癌HepG2 细胞体外抑制作用的研究

目的:研究体外共培养情况下人胚胎干细胞H9 对肝癌HepG2 细胞的抑制作用。方法:建立人胚胎干细胞(H9) 与肝癌HepG2 细胞共培养体系,显微镜下观察胚胎干细胞对肿瘤细胞生物学行为的影响,流式细胞仪检测H9 细胞对肿瘤细胞的凋亡与周期的影响,Transwell 小室法检测H9 细胞对HepG2 细胞侵袭和迁移的影响,基因芯片分析共培养后HepG2 细胞全基因组的表达谱变化。结果:结果发现共培养过程中,肝癌HepG2 细胞生长受到抑制,随共培养时间延长,细胞数量逐渐减少,出现老化或凋亡迹象;流式细胞术检测发现HepG2 细胞凋亡率显著增加,细胞周期被阻滞于G0/ G1 期;Transwell 实验发现HepG2 细胞侵袭、迁移力均降低;基因芯片结果发现HepG2 细胞全基因组表达谱发生了显著变化,差异基因涉及多条信号通路。结论:人胚胎干细胞H9 体外对人肝癌细胞HepG2 有一定程度的抑制作用。     

The effect of organic acids on phytohaemagglutinin-activated proliferation of human lymphocytes in vitro

The present study assesses the effects of 25 organic acids on in vitro proliferation of human peripheral lymphocyte stimulated with phytohaemagglutinin (PHA). Lymphocytes were cultured in flat-bottomed 96-well microplates at 37°C for 96 h in the presence of the mitogen and of one acid. The concentrations of organic acids tested in the cultures were from 1 to 5 mM, corresponding to those usually found in the blood of patients with organic acidaemias. Cellular growth was measured by the incorporation of 6[³H]-thymidine into cellular DNA. We observed that tiglic (2-methylcrotonic), α-keto-β-methylvaleric, aminoadipic, sebacic and alpha-ketoisocaproic acids strongly inhibited lymphocyte DNA synthesis, whereas α-ketoisovaleric, propionic, α-hydroxy-β-methylvaleric, α-methylbutyric and isobutyric acids moderately suppressed DNA synthesis. Lactic and ethylmalonic acids, however, stimulated DNA synthesis. The most inhibitory acids were added to cultures at different times after the beginning of the incubation period. Except for tiglic acid, whose action persisted even after 48 h from the onset of cultures, the others acted only when added during the first 24 h. The present study demonstrated that organic acids modulate DNA synthesis in mitogen-stimulated human lymphocytes.