壳多糖保肝作用的实验研究

目的：观察壳多糖(chitosan)保肝的药理作用。方法：按200 mg·kg 1的剂量给予小鼠灌胃给药，观察壳多糖对四氯化碳致小鼠急性肝损伤的组织学变化及其对转氨酶、脂质过氧化的影响。结果：壳多糖组小鼠肝细胞变性、坏死明显轻于造模组；壳多糖组ALT水平，血浆、肝匀浆过氧化脂质(LPO)及血浆丙二醛(MDA)含量亦显著低于造模组，组间比较差异具有极显著性或显著性(P＜0.01或P＜0.05)。结论：壳多糖对小鼠急性实验性肝损伤有明显的保肝降酶作用，机制可能与其抗自由基损伤、抑制脂质过氧化反应等有关。     

赤芍水提物对四氯化碳致肝损伤大鼠的保护作用

目的：探讨赤芍水提取物对四氯化碳(CCl4)中毒性肝纤维化大鼠的治疗作用。方法：复制大鼠CCl4肝纤维化模型，以马洛替酯为阳性对照，采用光镜观察组织学改变， 测定血清丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、一氧化氮(NO)、透明质酸(HA)、层粘蛋白(LN)，肝组织羟脯氨酸(Hyp)、丙二醛(MDA)以反映肝细胞损伤及肝纤维化的程度。结果：赤芍水提物能降低实验性肝纤维化大鼠血清中升高的ALT、AST、NO、HA、LN水平和肝组织中过高的Hyp、MDA的含量。病理组织学检查亦表明，赤芍水提物明显改善实验性肝纤维化。结论：赤芍水提物对实验性肝纤维化具有治疗作用。     

二硫化碳对小鼠心肌细胞肌浆网Ca2+-ATP酶基因表达的影响

目的探讨二硫化碳(CS2)对小鼠心肌细胞肌浆网Ca2 -ATP酶(SERCA2 a)表达的影响机制。方法将48只昆明小鼠分为4组给予不同剂量CS2(0~800 mg/m3)吸入染毒5周后,提取心肌的总RNA,运用逆转录聚合酶链反应技术来检测染毒小鼠心肌细SERCA2 a表达水平的变化。结果染毒前后体重差异无显著性(P>0.05),随着染毒剂量的增大,小鼠心肌细胞SERCA2 a的表达逐渐降低,与对照组比较差异有显著性(P<0.05)。结论CS2能降低小鼠心肌SERCA2 a的mRNA表达水平。     

CO2对犬缺血心肌侧支循环形成的影响及对心功能的保护作用

目的：观察经冠状动脉注入缺血心肌内CO2对犬缺血心肌侧支循环形成的影响反对心功能的保护作用。方法：采用健康杂种犬，建立犬急性心肌缺血模型。将模型犬分成两组，实验组10只，每日注射95％的CO2（2ml／kg）；对照组9只，每日只注射与实验组等量的肝素生理盐水，共14d；另选5只为空白对照组。两周后行冠状动脉造影、超声心动图、病理学、免疫组化染色检查．评价各组心功能及侧支血管形成状况。结果：实验组较对照组心脏缺血部位微血管明显增多，侧支循环形成，心功能改善。结论：CO2能加速扩张冠状动脉侧支血管，加速缺血区冠状动脉侧史循环的建立，增加心肌缺血区微血管的密度，改善缺血区的血液供应，并有效地保护心功能。     

10%四氯化碳致大鼠慢性肝损伤的研究

目的：研究10％四氯化碳致大鼠慢性肝损伤中间病理变化，为建立10％四氯化碳慢性肝损伤模型提供实验依据。方法：雄性Wistar大鼠80只，随机分为正常对照组和实验组。每组动物各40只。正常对照组腹腔注射玉米油，0．1ml／100g．bw；实验组腹腔注射10％四氯化碳，0．1ml／100g．bw。于实验期的第1、3、6和8周，两组动物分别腹腔注射玉米油和四氯化碳后48h放血处死，取肝组织作组织病理学观察。结果：实验组染毒1周后，肝小叶中央静脉周围大量细胞脂肪变性，肝小叶中央区有少量细胞气球样变；实验组染毒3周后，肝小叶中央静脉周围大量细胞脂肪变性，肝小叶中央区有少量细胞气球样变；实验组染毒3周后．肝小叶中央静脉周围大量细胞脂肪变性，肝小叶中央区有少量细胞气球样变；实验组染毒3周后，肝小叶中央静脉周围肝细胞气球样变加重；实验组染毒6周后，肝小叶中央静脉周围开始出现少量细胞坏死；实验组染毒第8周后，出现肝纤维化，未达到肝硬化。结论：建议少用该模型鉴定药物和保健食品对慢性肝损伤的保护作用。     

Changes in the gene expression associated with carbon tetrachloride-induced liver fibrosis persist after cessation of dosing in mice.

Recent studies have shown that gene expression profiles change in the livers of animals treated acutely with toxic chemicals such as carbon tetrachloride (CCl(4)). This study was undertaken to evaluate the changes in gene expression in mouse liver immediately after a long-term treatment with CCl(4) and possible effects of treatment cessation on these changes. Adult 129/Sv(pc)J mice were treated twice a week with CCl(4) at 1 ml/kg in olive oil for 4 weeks. Hepatic pathological changes observed in the CCl(4)-treated mice included necrosis, inflammation, and fibrosis, along with increased serum alanine aminotransferase activities. Consistent with these changes, expression of genes involved in cell death, cell proliferation, metabolism, DNA damage, and fibrogenesis were upregulated as detected by microarray analysis and confirmed by real-time RT-PCR. Four weeks after CCl(4) treatment cessation, the pathological changes were recovered, with the exception of fibrosis, which was not completely reversed. Most of the gene expression profiles also returned to the control level; however, the fibrogenetic genes remained at a high level of expression. These results demonstrate that changes in gene expression profile correlate with pathological alterations in the liver in response to CCl(4) intoxication. Most of these changes are recoverable upon withdrawal of the toxic insult. However, liver fibrosis is a prolonged change both in gene expression and histopathological alterations.     

Chemical composition,antioxidant activity and hepatoprotective potential of Rourea induta Planch. (Connaraceae) against CCl4-induced liver injury in female rats

ObjectivesThe aim of this study was to evaluate the flavonoid content of an ethanolic leaf extract from the medicinal plant Rourea induta Planch. (RIEE) and to investigate its hepatoprotective potential and in vivo antioxidant effects.MethodsUsing samples from carbon tetrachloride-treated Wistar female rats treated orally with or without RIEE, we evaluated the aspartate aminotransferase, alanine aminotransferase, and total bilirubin levels in plasma; the levels of the hepatic oxidative stress markers catalase, superoxide dismutase, glutathione peroxidase, and reduced glutathione in liver homogenates; and the thiobarbituric acid reactive substance levels. A histopathology study was performed. A quantitative analysis of the RIEE extract was performed using high-performance liquid chromatography to evaluate its flavonoid content.ResultsOral administration of RIEE significantly reduced carbon tetrachloride-induced elevations in the levels of plasma markers of hepatic damage and lipid peroxidation. It also rescued histopathologic alterations observed in the liver and levels of oxidative stress markers.ConclusionsRIEE exhibits antioxidant and hepatoprotective activities in vivo, which may be attributable to its flavonoids composition [hyperin (2), quercetin-3-O-β-xyloside (4), quercetin-3-O-α-arabinofuranoside (5), and quercetin (6)].     

Exposure assessment of carbon nanotube manufacturing workplaces

Seven CNT (carbon nanotube) handling workplaces were investigated for exposure assessment. Personal sampling, area sampling, and real-time monitoring using an SMPS (scanning mobility particle sizer), dust monitor, and aethalometer were performed to characterize the mass exposure, particle size distribution, and particle number exposure. No workplace was found to exceed the current ACGIH (American Conference of Governmental Industrial Hygienists) TLVs (threshold limit values) and OELs (occupational exposure levels) set by the Korean Ministry of Labor for carbon black (3.5?mg/m³), PNOS (particles not otherwise specified; 3?mg/m³), and asbestos (0.1 fiber/cc). Nanoparticles and fine particles were most frequently released after opening the CVD (chemical vapor deposition) cover, followed by catalyst preparation. Other work processes that prompted nanoparticle release included spraying, CNT preparation, ultrasonic dispersion, wafer heating, and opening the water bath cover. All these operation processes could be effectively controlled with the implementation of exposure mitigation, such as engineering control, except at one workplace where only natural ventilation was used.     

HEPATOPROTECTIVE EFFECT OF AMOORA ROHITUKA

Abstract

Antihepatotoxic activity of a resuspended residue of the alcohol extract of Amoora rohituka W & A. (Meliaceae) was studied in rats with hepatic injury induced by carbon tetrachloride. Carbon tetrachloride (1 ml/kg, i.p.) was administered twice a week for 3 weeks and an extract of A. rohituka (50 mg/kg/day) was given orally for the same period. The rats were sacrificed 24 h after the last CC1₄ challenge. Carbon tetrachloride induced elevations of alkaline phosphatase (ALP), glutamate pyruvate transaminase (CPT), alanine aminotransferase (ALAT), glutamate oxaloacetate transaminase (GOT), aspartate aminotransferase (ASAT) and lactate dehydrogenase (LDH) and total plasma bilirubin concentration as well as depression of total plasma cholesterol concentration were reduced significantly by the concurrent treatment of rats with A. rohituka suspension. Changes in the histological architecture of the liver produced by CC1₄ where also protected by the administration of A. rohituka suspension. These results indicate that A. rohituka suspension possesses hepatoprotective action.     

The use of ablative lasers in the treatment of facial melasma

Melasma represents a pigmentary disorder that is difficult to treat. This study aims to broadly review the use of ablative lasers (Er:YAG and CO2) in the treatment of melasma, presenting the level of evidence of studies published to date. A total of 75 patients were enrolled in four case series studies (n=39), one controlled clinical trial (n=6) and one randomized controlled clinical trial (n=30). Studies on the Er:YAG laser showed better results with the use of short square-shaped pulses, which determined low rates of post-inflammatory hyperpigmentation and long-lasting maintenance of results. Likewise, studies on the CO2 laser proved the benefits of short pulse duration along with low-density energy. Post-treatment maintenance with the use of antipigmenting creams was necessary and effective to sustain long-term results. Ablative lasers may represent another useful and effective tool against melasma. Postinflammatory hyperpigmentation and difficulty in sustaining long-term results still represent the main limitations to a broader use of ablative lasers. Based on actual evidence, the use of this technology should be restricted to patients with recalcitrant disease. Further studies will help establish optimal laser parameters and treatment regimens.