Lipid peroxidation,low-level chemiluminescence and regulation of secretion in the mammary gland

In mammary explants of lactating mice, changes in the intensity of chemiluminescence (CL) were observed after the addition to the incubation medium of hormones and mediators that are involved in the regulation of secretion: oxytocin, acetylcholine, epinephrine and norepinephrine. A 15-min period of treatment with oxytocin, epinephrine or norepinephrine changed the level of thiobarbituric acid-reactive substances (TBARS). Two mammary explants, one of which was treated with oxytocin, acetylcholine, epinephrine or norepinephrine, were found to interact even when separated by a quartz glass wall. Analysis of the level of TBARS formation in these two explants showed that the observed interactions might be connected with light emission resulting from lipid peroxidation (LP) processes. The possible role of LP and low-level CL in the regulation of mammary gland secretion is discussed.     

Photobiochemistry without light

Summary Efficient excited state formation — much higher than that hitherto expected — may occur in organelles and in intact cells. Excited triplet states can be enzymatically generated in high yields by different routes. An example is the oxidation of isobutanal to acetone and formic acid, catalyzed by horseradish peroxidase. Other enzymatic systems that generate triplet carbonyls are linear aliphatic aldehydes when oxidized by peroxidase/O₂, or the indole-3-acetic acid/peroxidase/O₂-reaction. The latter is widespread in plants.This new field — photobiochemistry without light — has led to a growing awareness of the idea that cells may utilize excited states to trigger photochemical processes even in the dark. Such phenomena are of considerable importance, also for the understanding of weak photon emission from biological systems.     

L-肉碱及耐力运动对过氧化物酶体增殖物激活受体影响的研究

过氧化物增殖物激活受体(PPARs)是一类能被脂肪酸以及外源性过氧化物酶体增殖剂(PP)等激活的核内受体，它与脂肪代谢以及脂肪分化、沉积密切相关。L-肉碱、适度的运动可改善脂质代谢，而脂质代谢的中间以及最终代谢产物是PPARs的配体，PPARs被其激活又进一步影响脂质代谢。     

Efficacy of tumor cell vaccine after incorporating monophosphoryl lipid A (MPL) in tumor cell membranes containing tumor-associated ganglioside

Murine B16 melanoma expresses the ganglioside. GM₃. GM₃ shed from tumor cells is immunosuppressive and promotes tumor growth¹. Reduction or elimination of the shed GM₃ could be therapeutic, and the anti-GM₃ antibodies may reduce and clear the shed ganglioside. To test this hypothesis, mice were challenged with tumor cells, with or without inducing anti-GM₃ antibody response. Since gangliosides are poor immunogens and T-cell independent antigens, an adjuvant (monophosphoryl lipid A (MPL), a non-toxic lipid A ofSalmonella), directed against B-cells, was employed. MPL was incorporated onto liposomes and into the surface membrane of B16 mouse melanoma cells; both are rich in GM₃. C57BL/6J mice immunized with MPL-liposomes or MPL-B16 cells responded with elevated levels of anti-GM₃ IgM. Non-immunized mice or mice immunized with B16 cells alone or ganglioside GM₃ alone (without MPL) elicited poor anti-GM₃ IgM response, confirming the GM₃'s immunologic crypticity and MPL's immunopotentiating effect. MPL's immunopotentiating effect was improved by coupling it to melanoma cell membranes C57BL/6J mice were immunized with irradiated B16 alone or MPL alone or MPL-conjugated irradiated B16. After three weekly immunizations, each mouse received a challenge dose of viable syngeneic B16. Neither MPL alone nor B16 alone had a significant effect on tumor growth or host survival; however, administration of MPL-conjugated B16 cells significantly prevented tumor growth and prolonged survival. Our results indicate that MPL-incorporated B16 cells augment the anti-GM₃ IgM response, which may reverse GM₃-induced immunosuppression by eliminating tumor-derived GM₃, and restore immunocompetence.     

大豆异黄酮对卵巢切除大鼠糖脂代谢和血清瘦素、抵抗素表达的影响

为探讨大豆异黄酮对卵巢切除大鼠糖脂代谢和血清瘦素、抵抗素表达的影响,将12周SD大鼠分成3组,假手术(Sham)组、卵巢切除(OVX)组和大豆异黄酮(OVX+Gen)组,每组7只,卵巢切除术后10 d,OVX组和Sham组大鼠每天腹腔注射生理盐水0.1 ml/只,OVX+Gen组每天注射大豆异黄酮0.2 mg/只,连续注射30 d后处死取血,检测子宫病理改变、血糖血脂和胰岛素水平、血清瘦素和抵抗素含量.结果发现卵巢切除后大鼠总胆固醇、HDL和LDL均增加(P<0.05),但胰岛素、血糖、甘油三酯、血清瘦素和抵抗素水平变化不明显(P>0.05);卵巢切除后补充大豆异黄酮,可促进子宫内膜上皮部分增生,但胰岛素、血糖、总胆固醇、甘油三酯、LDL和HDL、血清瘦素和抵抗素水平均无明显变化(与OVX组相比,P>0.05),结果提示大豆异黄酮对卵巢切除大鼠糖脂代谢参数和血清瘦素、抵抗素水平影响不大.     

两种强度健身跑运动改善中年男子血脂代谢的研究

探讨两种强度健身跑运动对中年男性血脂异常患者血脂代谢的影响.方法：将45名中年男性血脂异常患者随机分成乳酸阈强度组（L4组）、阈下强度组（L2组）和对照组（C组）三组.L2组和L4组分别以2mmol/L和4mmol/L乳酸对应强度,进行为期16周健身跑运动,C组不参加任何运动.结果：16周运动干预后,L2组和L4组血脂指标均有改善,而且16周运动后L4组TG、TC/HDL-c、LDL-c/HDL-c和血脂综合指数（LCI=TC.TG.LDL-c/HDL-c）的降低量明显高于L2组（p〈0.05）.同时体脂百分比、体重及体重指数亦明显降低（p〈0.01）.16周前后,C组血脂、身体成分各指标亦无显著性差异（P〉0.05）.运动干预后,体脂百分比的降低与TG、HDL-c与LDL-c/HDL-c密切相关（p〈0.05）.结论：16周健身跑运动对中年血脂异常患者的血脂、身体成分有良好的改善作用,且以4mmol/L乳酸对应强度运动效果最为明显;但对于血脂与体脂百分比改变的相关性有待于进一步的研究.     

情绪的表露对大鼠胃粘膜脂质过氧化作用的影响

采用冷冻加束缚大鼠,观察情绪的表露对应激性胃粘膜脂质过氧化作用的影响。结果显示,情绪的表露对应激性胃粘膜损伤具有保护作用,同时能较显著地抑制应激引起的胃粘膜丙二醛（ＭＤＡ）含量的升高。正常应激时大鼠胃粘膜内谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）的活性降低,而超氧化物歧化酶（ＳＯＤ）的活性未见明显变化。情绪表露处理的大鼠可使应激时胃粘膜内ＧＳＨ－Ｐｘ活性降低恢复到正常水平,但ＳＯＤ活性未见明显影响。上述     

根结线虫侵染对番茄叶片保护酶活性及膜脂过氧化的影响

以番茄品种雄风158为试材，研究了根结线虫侵染对其保护酶活性和膜脂过氧化的影响。结果显示，线虫侵染后，番茄叶片的过氧化物酶（POD）、过氧化氢酶（CAT）活性和丙二醛（MDA）含量均远高于未接种番茄。POD活性在接种后1—15d呈上升趋势，然后开始下降，15d时出现峰值；CAT活性在接种后5—15d呈下降趋势，5d时出现峰值；MDA含量持续上升至20d时为最大值；超氧化物歧化酶（SOD）的活性接种1—15d高于未接种番茄，15—20d略低于未接种番茄，10d时出现峰值。研究结果表明，MDA含量可以作为早期判断番茄是否感染根结线虫的一项生理指标。     

Fatty-acids and their <Emphasis Type="Italic">δ</Emphasis><Superscript>13</Superscript>C characteristics of seep carbonates from the northern continental slope of Gulf of Mexico

Here we reported the fatty-acids and their δ¹³C values in seep carbonates collected from Green Canyon lease block 185 (GC 185; Sample GC-F) at upper continental slope (water depth: ~540 m), and Alaminos Canyon lease block 645 (GC 645; Sample AC-E) at lower continental slope (water depth: ~2200 m) of the Gulf of Mexico. More than thirty kinds of fatty acids were detected in both samples. These fatty acids are maximized at C₁₆. There is a clear even-over-odd carbon number predominance in carbon number range. The fatty acids are mainly composed of n-fatty acids, iso-/anteiso-fatty acids and terminally branched odd-numbered fatty acids (iso/anteiso). The low δ¹³C values (−39.99‰ to −32.36‰) of n-C₁₂:0, n-C₁₃:0, i-C₁₄:0 and n-C₁₄:0 suggest that they may relate to the chemosynthetic communities at seep sites. The unsaturated fatty acids n-C_18:2 and C_18:1△⁹ have the same δ¹³C values, they may originate from the Beggiatoa/Thioploca. Unlike other fatty acids, the terminally branched fatty acids (iso/anteiso) show lower δ¹³C values (as low as −63.95‰) suggesting a possible relationship to sulfate reducing bacteria, which is common during anaerobic oxidation of methane at seep sites.     

野生山葡多酚对高脂血症小鼠脂代谢的影响及抗氧化作用研究

目的研究野生山葡多酚对脂代谢的影响及抗脂质过氧化作用.方法观察不同浓度野生山葡多酚对高脂血症小鼠血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)及脂质过氧化(LPO)水平的影响.结果野生山葡多酚200 mg/(kg·d-1)×56 d组小鼠血清TG,TC,LPO含量明显低于高脂饲料组(P＜0.05,P＜0.01,P＜0.01),而野生山葡多酚100 mg/(kg·d-1)×56 d组小鼠血清HDL-C含量显著高于高脂饲料组(P＜0.01),动脉硬化指标(AI)显著低于高脂饲料组(P＜0.01).结论野生山葡多酚具有显著降低血脂含量和抗脂质过氧化作用.提示野生山葡多酚具有防治动脉硬化作用.