Enhancement of sterol synthesis by the monoterpene perillyl alcohol is unaffected by competitive 3-hydroxy-3-methylglutaryl-CoA reductase inhibition

Monoterpenes such as limonene and perillyl alcohol (PA) are currently under investigation for their chemotherapeutic properties which have been tied to their ability to affect protein isoprenylation. Because PA affects the synthesis of isoprenoids’ such as ubiquinone’ and cholesterol is the end product of the synthetic pathway from which this isoprenoid pathway branches’ we investigated the effects of this compound upon cholesterol metabolism in the colonic adenocarcinoma cell line SW480. PA (1 mM) inhibited incorporation of ¹⁴C-mevalonate into 21–26 kDa proteins by 25% in SW480 cells. Cholesterol (CH) biosynthesis was assessed by measuring the incorporation of ¹⁴C-acetate and ¹⁴C-mevalonate into 27-carbon-sterols. Cells treated with PA (1 mM) exhibited a fourfold increase in the incorporation of ¹⁴C-acetate but not ¹⁴C-mevalonate into cholesterol. Mevinolin (lovastatin)’ an inhibitor of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase’ at 2 μM concentration’ inhibited CH synthesis from ¹⁴C-acetate by 80%. Surprisingly’ concurrent addition of mevinolin and PA did not significantly alter the stimulatory effects of PA. As observed differences in ¹⁴C-acetate and ¹⁴C-mevalonate precursor labeling could indicate PA affects early pathway events’ the effects of this monoterpene on HMG-CoA reductase activity were evaluated. Unexpectedly’ 1 mM PA did not stimulate activity of this enzyme. Consistent with its action as a reversibly bound inhibitor’ in washed microsomes’ 2 μM mevinolin pretreatment increased reductase protein expression causing a 12.7 (±2.4)-fold compensatory HMG-CoA reductase activity increase; concurrent treatment with 1 mM PA attenuated this to a 5.3 (±0.03)-fold increase. Gas chromatographic analysis confirmed CH was the major lipid present in the measured thin-layer chromatography spot. Since ¹⁴C-acetate incorporation into free fatty acid and phospholipid pools was not significantly affected by PA treatment’ nonspecific changes in whole acetate pool sizes were not indicated. Because increases in endogenous CH synthesis should result in compensatory changes in exogenous sterol utilization’ the effects of PA upon low density lipoprotein (LDL) receptor activity were evaluated. Consistent with the observed increases in CH synthesis’ 1 mM PA decreased ¹²⁵I-LDL internalization to 50% of the fetal bovine serum control; concurrent addition of 2 μM mevinolin attenuated this effect to a reduction of 80% of the control value. Data suggest that in certain colonic tumor cells PA strongly affects cholesterol metabolism via a mechanism of action that is insensitive to the HMG-CoA reductase inhibitor mevinolin.     

A single oral administration of conjugated linoleic acid enhanced energy metabolism in mice

We investigated the effect of a single oral administration of conjugated linoleic acid (CLA) on energy metabolism in mice. Male Std ddY mice were orally administered CLA (5 mL/kg weight) or linoleic acid (5 mL/kg weight) (both solutions at concentrations of 73.5%) as a control. Oxygen consumption was significantly greater in the CLA-administered mice than in the control mice. Respiratory quotient was slightly lower in the CLA-administered mice than in the control mice. We calculated fat and carbohydrate oxidation from oxygen consumption and respiratory quotient. Fat oxidation in the CLA-administered mice was significantly higher than in the control mice, and there was no difference in carbohydrate oxidation. Serum concentrations of noradrenalin and adrenalin in the CLA administered mice were significantly higher than in the control mice. These results suggested that CLA enhanced sympathetic nervous activity and energy metabolism.     

Comparison of bile acid synthesis determined by isotope dilution versus fecal acidic sterol output in human subjects

Fecal acidic sterol output has been found to be much lower than bile acid synthesis determined by isotope dilution (J. Lipid Res. 17: 77, 1976). Because of this confusing discrepancy, we compared these 2 measurements done simultaneously on 13 occasions in 5 normal volunteers. In contrast to previous findings, bile acid synthesis by the Lindstedt isotope dilution method averaged 16.3% lower than synthesis simultaneously determined by fecal acidic sterol output (95% confidence limit for the difference −22.2 to −10.4%). When one-sample determinations of bile acid pools were substituted for Lindstedt pools, bile acid synthesis by isotope dilution averaged 5.6% higher than synthesis by fecal acidic sterol output (95% confidence limits −4.9 to 16.1%). These data indicate that the 2 methods yield values in reasonably close agreement with one another. If anything, fecal acidic sterol outputs are slightly higher than synthesis by isotope dilution.     

Corrosion inhibition of steel in sodium chloride solution by undoped polyaniline epoxy blend coating

In this study an undoped polyaniline (PAni) was synthesized by chemical oxidative polymerization with ammonium persulfate as an oxidizing reagent. The synthesized PAni was used as a corrosion inhibitive pigment in an epoxy matrix. The corrosion protection performance of steel coated panels in 3.5% sodium chloride solution was evaluated via determination of open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). It was found that after 300 days of immersing the resistance of coating was about 4 × 10⁵ Ω cm². The OCP was shifted to the noble region due to the passivation effect of PAni pigment. Besides, the phase angle (theta) at 10 kHz was stable around 87 ± 1° during immersion period. Results revealed that PAni pigmented paint showed acceptable protection against the corrosion of carbon steel in 3.5% sodium chloride solution.     

Chemical synthesis of cross-linked polyaniline by a novel solvothermal metathesis reaction of p-dichlorobenzene with sodium amide

We reported the chemical synthesis of cross-linked polyaniline (PANI) by a novel solvothermal metathesis reaction of p-dichlorobenzene (C₆H₄Cl₂) with sodium amide (NaNH₂) in benzene at 220 °C. In this method, the aniline monomer and complicated treatment were needless and the yield of final products was over 50%. The as-synthesized brown samples were NMP-soluble but water-insoluble; and they were characterized by XRD, FT-IR, UV-vis absorption, XPS, elemental analysis, TGA, and TEM. It was found that solvents have significant influence on the final product. The predominant mechanism of chain growth in PANI polymerizations was proposed as the ionic S_NAr process; however, further theoretical and experimental investigations are needed to obtain the undoubted evidences. We believe that this novel solvothermal metathesis reaction will give us a new guideline for the synthesis of some polymers.     

Ⅱa型宝石级金刚石大单晶研究最新进展

用合金触媒利用温度梯度法合成优质Ⅱ a型宝石级金刚石.研究发现,在约5.4GPa和约1300℃的条件下,除氮剂的加入使合成金刚石的温度区间变窄及金刚石晶体生长过程中更易俘获包裹体而出现熔坑,从而影响晶体的生长速度.实验解决了组装的稳定性问题;并通过调整组装,在除氮剂合适的掺入量下,使合成优质金刚石的最大生长速度达到2.16mg/h.结果实验获得了4.3mm的优质Ⅱa型金刚石大单晶.红外测试分析表明该金刚石含氮量小于10-7.     

Microscopic single particle characterization of zeolites synthesized in a soil polluted by copper or cadmium and treated with coal fly ash

In the perspective of the development of new soil remediation technologies, zeolites can be directly synthesized in soil from fused coal fly ash to reduce heavy metal mobility and availability. Such a process promotes the formation of metal hydroxide/oxide precipitates which can be also occluded inside the structure of the forming minerals. In this study, different types of zeolites (zeolite X, P, and A) were synthesized by treating soil samples, artificially contaminated by high concentrations of Cu or Cd ions, with fused coal fly ash at 30 and 60 °C. The formed zeolites were characterized for their amount, structure, chemical composition and size. To accomplish this survey, besides quantitative X-ray diffraction analyses (XRD), an automated single particle analysis (ASPA) method using electron probe X-ray microanalysis (EPXMA) was employed for the first time for direct zeolite characterization in soil samples. The obtained results provide new information for assessing the role of heavy metals in zeolite crystallization in coal fly ash-treated soils. Heavy metal contamination, while not significantly hindering the zeolite formation process, can influence crystal size and preferentially drive zeolite synthesis toward the formation of sodalite unit-based zeolite X and zeolite A, even at 60 °C. The presence and nature of metal precipitate occlusions inside the forming zeolite minerals might have also favored the preferential synthesis of certain zeolitic structures.     

Regulation of mevalonate synthesis in low density lipoprotein receptor knockout mice fed n-3 or n-6 polyunsaturated fatty acids

3-Hydroxy-3-methylglutaryl (HMG)-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis, catalyzes the formation of mevalonate which is also required for cell proliferation. Changes in HMG-CoA reductase may mediate the differential effects of n-3 and n-6 polyunsaturated fatty acids (PUFA) on experimental mammary tumorigenesis, but the mechanisms by which these fatty acids regulate HMG-CoA reductase are unclear. To determine whether the low density lipoprotein receptor (LDL-R) is required for this regulation, groups of female LDL-R knockout (−/−) and wild-type (+/+) mice were fed 7% fat diets rich in either n-3 (menhaden oil) or n-6 (safflower oil) PUFA for 1 wk. Dietary PUFA and deletion of the LDL-R had independent effects on HMG-CoA reductase and serum lipids, and a significant diet-gene interaction was observed. The effects of PUFA on HMG-CoA reductase in the mammary gland, but not the liver, were mediated by the LDL-R. We also observed that differences in HMG-CoA reductase and serum LDL-cholesterol, high density lipoprotein cholesterol, and triglycerides between −/− and +/+ mice were dependent on whether the mice were fed n-3 or n-6 PUFA. Differences between −/− and +/+ mice were much greater when animals were fed n-6 PUFA rather than n-3 PUFA. These results show that the LDL-R mediates the effects of PUFA on HMG-CoA reductase in the mammary gland but not the liver. Furthermore, the composition of dietary PUFA profoundly influences the effects of deleting the LDL-R on HMG-CoA reductase and serum lipids and suggests that diet may influence the phenotype of other knockout or transgenic animals. This work was presented in part at the Third Congress of the International Society for the Study of Fatty Acids and Lipids, June 1–5, 1998, Lyon, France.     

Effects of a single ingestion of sodium taurocholate on esterified cholesterol concentration in liver and cholesterol turnover in the rat

The overall response of the rat’s cholesterol metabolism to a single ingestion of taurocholate (80 mg) was studied with the isotopic equilibrium method. The bile acid production, measured by the daily¹⁴CO₂ output of rats in isotopic equilibrium of [26-¹⁴C]-cholesterol, initially decreased and then increased. Conversely, the hepatic concentration of esterified cholesterol first increased and then decreased. Moreover, the ingestion of taurocholate increasing the intestinal absorption coefficient of dietary cholesterol increased the abosprtion and decreased the fecal excretion and the intestinal biosynthesis of cholesterol. The balance of these last effects is an excess cholesterol inflow. The classical hypothesis of negative feedback regulation of bile acid production fails to explain the observed biphasic effect of taurocholate. This compound, when its origin is exogenous, appears to stimulate the storage of esterified cholesterol in the liver, at the expense of bile acid synthesis. This accumulation rate takes into account not only the decrease in cholesterol transformation into bile acids but also the excess inflow of cholesterol. As the exogenous taurocholate was eliminated from the body, cholesteryl ester hydrolysis occurred and provided a supplementary source of free cholesterol for bile acid synthesis.     

单槽脉冲电沉积法制备FePt薄膜

以FeSO4.7H2O和H2PtCl6.6H2O分别作为Fe2+源和Pt4+源,以铂片为阳极,纯铜片为阴极,采用单槽脉冲电沉积法制备FePt薄膜,通过X-射线衍射仪(XRD)、带有能谱的场发射扫描电镜(FESEM-EDAX)、振动样品磁强计(VSM)分析手段对薄膜进行了表征。结果表明,新制备的FePt薄膜组成为Fe22Pt58O20,具有面心立方(fcc)结构,FePt薄膜的矫顽力为2.0 kA/m,饱和磁化强度为420 kA/m,具有软磁性。     

醛-酮催化氨化合成吡啶及其烷基衍生物研究进展

醛-酮催化氨化合成吡啶及其烷基衍生物(俗称吡啶碱)是工业生产吡啶类化合物的主要方法。对醛-酮催化氨化合成吡啶碱的反应机理、催化剂的进展进行了介绍,阐述了无定形硅铝酸盐作为催化剂合成吡啶碱选择性和寿命低的原因,以金属对无定形硅铝酸盐或择形硅铝酸盐分子筛进行修饰可改进催化剂的催化性能。择形硅铝酸盐分子筛的酸性对吡啶类产物的分布有显著影响,改变分子筛的硅铝比,可以调节催化剂的酸性,从而提高生成吡啶碱的选择性。     

Removal of sulfuric acid aerosol in a wet electrostatic precipitator with single terylene or polypropylene collection electrodes

Wet electrostatic precipitators (ESPs) are good options for effective control of sulfuric acid aerosol emission. However, various problems caused by materials and non-uniform distribution of water film limited the applicability of typical wet ESPs. Research on ESP technology has tried to find more suitable and anti-corrosive methods to solve these imperfections. This research was inspired by the requirement to replace rigid collection electrode by single terylene or polypropylene fabrics. A patented system was designed, and the capillary difference between terylene and polypropylene fabrics was illustrated. Contrastive V–I curves of different collection electrodes were investigated under same conditions. The effects of several important parameters on the removal of sulfuric acid aerosol were analyzed. The results demonstrated that the variations of absorbed mass were significantly influenced by physical properties of the liquids and the structure of fabrics. The behavior of the new ESP was consistent with the typical ESP using a thimbleful of water penetrating terylene or polypropylene collection electrode via capillary flow. The collection efficiencies by terylene and polypropylene fabrics were higher than those by fiberglass reinforced plastics (FRP) under certain conditions. The collection efficiency had linear relationship with specific surface area (SCA) and mass concentration. The collection efficiency increased with increasing electric field strength, average diameter of particles and with decreasing gas temperature. As long as there was any water on the collector surface, any particle would exhibit similar collection efficiencies, whether of high resistivity or not. Experimental and theoretical investigations indicated that single terylene or polypropylene collection electrode had significant advancement which could improve wet ESP applications, such as superior performance and continuous operation ability compared with typical materials.     

Prevention of obesity in Avy/a mice by dehydroepiandrosterone

Dehydroepiandrosterone, a mammalian glucose-6-phosphate dehydrogenase inhibitor, preventedA ^vy /a mice from becoming obese. Decreased accumulation of triacylglycerol accounted for a large portion of the weight difference between treated and controlA ^vy /a mice. Hepatic lipogenesis as measured by³H₂O incorporation into total lipid was less in the dehydroepian drosterone-treated mice. Dehydroepiandrosterone did not suppress appetite and had no apparent toxic effects at the doses used, and its weight controlling effects were reversible upon withdrawal of treatment.     

First Gewald reaction ignited by sodium polysulfide: greener ultrasound-promoted synthesis of substituted 2-aminothiophenes in the absence of catalyst

In this paper, a modified and facile Gewald reaction triggered by sodium polysulfide in the absence of catalytic base was developed. This approach involves a one-pot ultrasound-irritated aqueous reaction between ketones or aldehydes, malononitrile, and sodium polysulfide, which are converted into the corresponding 2-aminothiophene derivatives in moderate to high yields. In comparison with conventional methods, the prominent features of this sonocatalyzed procedure are experimental simplicity, good functional group tolerance, atom efficiency, and the use of water as a green solvent.     

单剂水痘疫苗接种后人群中暴发水痘疫情的原因分析

目的通过对单剂水痘疫苗高接种率学校中暴发的水痘疫情分析,评估疫苗的免疫持久性。方法采用现场流行病学方法对2011年10月至2012年1月虹口区单剂水痘疫苗高接种率学校中水痘暴发疫情进行调查和分析。结果在2011年10月16日至2012年1月13日疫情暴发期间,累计发现36例水痘病例,罹患率为5.4%,症状以发热、皮疹为主,仅27.8%的病人呈轻度或中度发热,且均为轻型水痘病例。发病班级的水痘罹患率在2.2%～34.1%之间,其中,男性为21.21%,女性为19.23%,病例发病时间主要集中在11月9～13日,占总病例的36.1%,呈2、3、4代病例的传播特征;发病班级单剂水痘疫苗接种率为95.48%,未发现接种史与水痘发病有关(P>0.05),患病的相对危险度(Relative risk,RR)为0.8;接种年龄组间水痘发病率差异无统计学意义(P>0.05);36例病例中,接种疫苗与发病时间的间隔中位数为66月,进口与国产水痘疫苗接种后,水痘发病率差异无统计学意义(P>0.05);暴发疫情病例中有免疫史人群的比例显著高于散发病例(P<0.05),比值比(Odds ratio,OR)为11.3。结论单剂水痘疫苗接种,可预防重症病例,但不能完全预防水痘暴发。建议首剂水痘疫苗接种后5～6年加强接种,或在发生疫情时,对首剂接种≥5年的无水痘患病史的密切接触者进行应急接种。     

Specific inhibition of hepatic fatty acid synthesis exerted by dietary linoleate and linolenate in essential fatty acid adequate rats

Dietary linoleate and linolenate were investigated for their ability to specifically inhibit liver and adipose tissue lipogenesis in meal-fed (access to food 900-1,200 hr), essential fatty acid (EFA) adequate rats. Supplementing a high carbohydrate diet containing 2.5% safflower oil with 3% palmitate 16∶0, oleate 18∶1, or linoleate 18∶2 did not affect in vivo liver or adipose tissue fatty acid synthesis. However, 18∶2 addition to the basal diet did result in a significant (P<0.05) decline of liver fatty acid synthetase (FAS) and glucose-6-phosphate dehydrogenase (G6PD) activities. When the safflower oil content of the basal diet was reduced to 1%, the addition of 3% 18∶2 or linolenate 18∶3 significantly (P<0.05) depressed hepatic FAS, G6PD, and in vivo fatty acid synthesis by 50%. Addition of 18∶1 caused no depression in hepatic FAS activity but did result in a significant (P<0.05) decline in liver G6PD activity and fatty acid synthesis which was intermediate between basal and basal +18∶2-or+18∶3-fed animals. Adipose tissue rates of lipogenesis were completely unaffected by dietary fatty acid supplementation. Similarly, the addition of 3 or 5% 18∶3 to a basal diet for only one meal resulted in no change in lipogenesis relative to that in animals fed the basal diet. The data indicate that, like rats fed EFA-deficient diets, dietary 18∶2 and 18∶3 exert a specific capacity to depress rat liver FAS and G6PD activities and rate of fatty acid synthesis. Michigan Agricultural Experiment station Journal Article No. 7581. D.R. Romsos is the recipient of Career Development Award K04 AM 00112     

Continuous synthesis of glycerides by lipase in a microporous membrane bioreactor

A membrane bioreactor was developed for continuous synthesis of glycerides by lipase to overcome the drawbacks associated with the usual operation in an emulsion system. One unit (total area: 726 cm²) of flat, plate-type dialyzer was used as the membrane bioreactor at 40 C. The glycerol solution, containing bacterial lipase and water, was supplied continuously to 1 side of a sheet of microporous polypropylene membrane (strongly hydrophobic) and the effluent was recycled, while undiluted liquid fatty acid (oleic or linoleic) was fed continuously to the opposite side of the membrane and came in contact with a glycerol-water-lipase solution to cause the reaction. The product, glycerides, was obtained at the outlet, in a pure state, with no other phase. Highest conversion (ca. 90%) was obtained when the water content of the glycerol solution was 3–4%. As the accumulation of water produced by the reaction lowered the conversion, molecular sieves in a column that the glycerol solution passed through were used for optimal water content. The reaction could be continued at least for 1 month, yielding a conversion above 70% when 1% CaCl₂ was added in the glycerol solution. The main component of glycerides formed was almost equimolar amounts of mono-and diglycerides.     

Jet electrochemical etching of nickel in a sodium chloride medium assisted by a pulsed laser beam

This paper deals with the jet electrochemical etching of metal, using nickel drilling as an example; the performance of this technique was investigated as a function of the nozzle diameter and current density. The significance of the outer dissolution of metal, due to liquid spreading on the vertical substrate facing the nozzle, was estimated; the hole size was compared to the nozzle diameter. Moreover, a pulsed beam was shown to improve the precision of the edge. Applications to shape patterning are presented and discussed.     

The one-pot synthesis of 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes catalyzed by task-specific ionic liquid

A Brønsted-acidic task-specific ionic liquid, 1-methyl-3-propane sulfonic-imidazolium hydrosulfate ([MIMPS]HSO₄), was employed as a catalyst for the synthesis of 14-alkyl- or aryl-14H-dibenzo[a,j]xanthenes via the one-pot condensation of β-naphthol with aliphatic or aromatic aldehydes. Various aliphatic and aromatic aldehydes were used in the reaction and in all cases the desired products were synthesized successfully. The novel synthesis method offers the advantages of high yields, short reaction times, simplicity and easy workup compared to the conventional method of syntheses. The catalyst could be recycled and reused five times without a noticeably decrease in its activity.