催化动力学光度法测定痕量苯酚

研究了在硫酸介质中苯酚对Ｉ＾－１催化Ｃｅ＾４＋－Ａｓ（Ⅲ）反应的抑制作用及其动力学条件。建立了用催化动力这光度法测定痕量苯酚的新方法，结果表明，在０．００１ｍｏｌ／ＬＣｅ（ＳＯ４）２，０．００１２５ｍｏｌ／Ｌ，Ａｓ２Ｏ３，０．０１ｍｇ／Ｌ，ＫＩ，０．０１２５ｍｏｌ／Ｌ，Ｈ２ＳＯ４和０．１３％（ｗ／ｖ）ＮａＣｌ溶液中测定苯酚，其表面摩尔吸光系数为２．１×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，线性范围     

铁的单点络合滴定法研究

本研究了Ｆｅ＾３＋的单点络合滴定法，导出了定量关系式，比较了以铂电极为指示电极和以ＰＶＣ膜四氯络铁（Ⅲ）阴离子电极为指示电极时电位测量的稳定性及所得的分析结果。在Ｆｅ＾３＋浓度为１．０００×１０＾－３ｍｏｌ／Ｌ时，１８次实验的平均值为１．０２×１０＾－４ｍｏｌ／Ｌ，相对偏差小于１．７％；Ｆｅ＾３＋在５．０×１０＾３ｍｏｌ／Ｌ以上时，相对偏差小于０．１％；其浓度小于１０＾－３ｍｏｌ／Ｌ而大于５×１     

铕对决明发根生长及有效成分生成的作用

以决明发根为材料,在培养基中附加０．００１～１０ｍｇ．Ｌ＾－１Ｅｕ＾３＋（ＥｕＣ１３）,测量发根的鲜重和干重,用高效液相色谱法测定游离蒽醌化合物含量。发有低剂量（０．００１,０．０１,１．０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋抑制生长,０．００１ｍｇ．Ｌ＾－１Ｅｕ＾３＋抑制作用最强,干重比对照降低２２％;较低剂量（１０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋处理的含量高于对照２６＾,高于Ｅｕ＾３＋１．０ｍｇ．Ｌ＾－１处理     

单柱离子色谱法测定痕量草酸根离子

本文采用单柱离子色谱系统测定了Ｃ２Ｏ＾２－４，以１．３ｍｍｏｌ／Ｌ葡萄糖酸钠／１．３ｍｍｏｌ／Ｌ硼砂为淋洗液测定Ｃ２Ｏ＾２－４，８常见阴离子Ｃｌ＾－，ＮＯ＾－３，ＨＰＯ＾２－４，ＳＯ＾２－４不干扰测定，Ｃ２Ｏ＾２－４的检出限为０．５７ｍｇ／Ｌ，相对标准偏差为１．０７％，工作曲线的线性范围为０．５７－５００ｍｇ／Ｌ，应用本方法测定了加Ｃ２Ｏ＾２－４的自来水样，Ｃ２Ｏ＾２－４的回收率为９９．５２％。     

荧光光度法同时测定稀土氧化物中铈钆铽

在０．６ｍｏｌ．Ｌ＾－１的 到介质中,分别用２５２、２７３、２２０ｎｍ作为Ｃｅ＾３＋、Ｇｄ＾３＋、Ｔｂ＾３＋的激发波和燕生相应最佳发波长为３５０、３１０和５４４ｎｍ。用盐酸体系测定混合样比用硫酸体系测定时,Ｇｄ＾３＋的检出限提高一倍,Ｇｄ＾３＋抗Ｃｅ＾３＋的干扰能力提高１０倍。同时测定三种离子的回收率在９５．３％～１０８．１％之间。     

添加剂Ce^4＋对化学镀镍的影响

本文探讨了添加剂Ｃｅ＾４＋对化学镀镍过程的影响，结果表明，Ｃｅ＾４＋可降低Ｎｉ－Ｐ合金镀层在３％ＮａＣｌ溶液中的腐蚀电流，提高其耐蚀性，并发现热处理可使其抗 腐蚀性能进一步提高。但各合金镀层在０．１ｍｏｌ／ＨＣｌ中的耐腐蚀性由于Ｃｅ＾４＋的加入普遍下降。     

丁基罗丹明B—钼酸盐光度法连续测定铈和钪

在聚乙烯醇（ＰＶＡ）存在下，丁基罗丹明Ｂ（ＢＲＢ）分别与铈钼、钪钼杂多酸络阴离子形成离子缔合物，其最大吸收均位于５７０ｎｍ，表面摩尔吸光度分别为εＣｅ＝３．９６×１０＾６Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，εＳｃ＝４．７１×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，服从比耳定律范围分别为０－２４μｇ／Ｌ Ｃｅ和０－６０μｇ／ＬＳｃ，测定极限为Ｃｅ１．０μｇ／Ｌ（ｎ＝１２）和Ｓｃ１．９μｇ／Ｌ（ｎ＝１０），对     

新催化动力学光度法测定痕量铝

根据ＡＩ＾３对ＫＢｒＯ３氧化Ｂａｎｇ花青褪色的催化行为,建立了测定痕量铝的催化动力学动力学分析方法。本法线性范围为０～１６０ｎｇ．ｍＬ＾－１,检出限为１．０ｎｇ．ｍＬ＾－１。除Ｃｕ＾２＋、Ｆｅ＾３＋、Ｃｒ（Ⅵ）外,其余离子均不影响测定。Ｆｅ＾３＋和Ｃｕ＾２＋、Ｃｒ（Ⅵ）的干扰可分别有效消除。测定了人发、茶叶和不中的,加标回收率为９８．４％～１０２％,ＲＳＤ为１．３％～２．１％（ｎ＝６）。     

用磷光寿命变化测定碘离子与磷光体反应动力学参数

利用Ｉ＾－促进系间窜越，加快发现过程，缩短磷光寿命的特点，研究Ｉ＾－量改变与色氨酸，色胺磷光寿命关系，分别为：τ＝３．９８ｅ＾－０．０６５８ｘ，与τ＝３．５ｅ＾－０．０８９９ｘ，应用静态分析，推导Ｓｔｅｒｎ－Ｖｏｌｍｅｒ式，计算平衡常数Ｋｓ与ｋｉ，分别为：０．１０９与０．２００ｍｍｏｌ；０．０２７与０．０５１ｓｍｍｏｌ＾－１。利用本法分析了酷氨酸，苯丙氨酸，Ｌ－色氨酸，牛血清白蛋白，葡糖苷酸酶。     

磷酸钛—磷钨酸铵的合成及性能研究

本文研究了磷酸－磷钨酸铵的合成，离子交换性能及化学结构等方面的性质。实验结果表明，该交换剂对Ｃｓ＾２＋具有很高的选择性和交换容量，在０．１ｍｏｌ／Ｌ ＨＮＯ３介质中，该交换剂对Ｃｓ＾＝的交换容量可达０．９５ｍｍｏｌ／ｇ，在１ＡＷ模拟废液中，对ＣＳ＾＋离子仍保持较高的变换容量。     

Selective purification of cardiac myosin by a high-performance salicylate affinity column

The cardiac muscle proteins, myosin and actin, were purified in one step using a salicylate-silica affinity column. The affinity columns were prepared by coupling sodium salicylate via its hydroxyl group to an Altex Ultraffinity-EP column. Crude detergent extracts from guinea pig hearts were passed through the column and the myosin-actin complex was then eluted with excess free salicylate or high salt. The affinity of cardiac myosin for immobilized salicylate was unique as myosin heavy chain from guinea pig leg muscle detergent extracts could not be purified by this procedure. Commercially purified rabbit leg muscle myosin also appeared to have no interaction with the salicylate affinity column, suggesting that the column is specific for cardiac myosin.     

A Comparative Study of the Phospholipid Profiles of Guinea Pig Cardiac Muscle and Bullfrog Cardiac and Thigh Skeletal Muscle,and their In-Vitro Differential Deacylation by Endogenous Phospholipases. Thin Layer Chromatographic and Densitometric Analysis

JPC – Journal of Planar Chromatography – Modern TLC - The phospholipid profiles of guinea pig and bullfrog cardiac muscle and of bullfrog thigh skeletal muscle before and after in-vitro...     

Ce3+对细胞内游离Ca2+的影响

研究了Ce^3 对肝细胞和V79细胞中游离Ca^2 的影响。低浓度的Ce^3 能使肝细胞内游离Ca^2 浓度增高，高浓度的Ce^3 能使肝细胞内游离Ca^2 浓度显著升高。Ce^3 可促进细胞外Ca^2 的内流，高浓度的Ce^3 对细胞是有毒性的。     

Negative inotropism of terpenes on guinea pig left atrium: structure-activity relationships

The aim of this work was to evaluate the pharmacological effect of seven structurally related terpenes on the contractility of cardiac muscle. The effect of terpenes was studied on isolated electrically driven guinea pig left atrium. From concentration–response curves for inotropic effect were determined the EC₅₀ and relative potency of such terpenes. Our results revealed that all terpenes, except phytol, showed ability to reduce the contractile response of guinea pig left atrium. Further, relative potency was directly related to the number of isoprene units and to the lipophilicity of the compounds. For example, sesquiterpenes farnesol and nerolidol showed higher relative potency when compared with the monoterpenes citronellol, geraniol and nerol. We can conclude that most of the evaluated terpenes showed a promising negative inotropism on the atrial muscle. Future studies are necessary to investigate their action mechanism.     

Five subtypes of muscarinic receptors are expressed in gastric smooth muscles of guinea pig

Muscarinic receptors play key roles in the control of gastrointestinal smooth muscle activity. However, specific physiological functions of each subtype remain to be determined. In this study, the nonselective cation channel activated by carbachol (I(CCh)) was examined in circular smooth muscle cells of the guinea pig gastric antrum using patch-clamp technique. 4-DAMP inhibited I(CCh) dose-dependently with IC(50) of 1.1 0.1 nM (n = 6). GTPgS-induced current, however, was not inhibited by 10 nM 4-DAMP. I(CCh) was not recorded in pertussis-toxin (PTX)-pretreated smooth muscle cells of gastric antrum. I(CCh) values in response to 10 mM CCh at a holding potential of 60 mV were -330 32 pA (n=4) and -15 3 pA (n = 6) in the control and PTX-treated cells, respectively (P 0.01). Sensitivities to nanomolar 4-DAMP and PTX suggest the possible involvement of m4 subtype. Using sequence information obtained from cloned guinea pig muscarinic receptor genes, it is possible to amplify the cDNAs encoding m1-m5 from guinea pig brain tissue. Single cell RT-PCR experiments showed that all five subtypes of muscarinic receptor were present in circular smooth muscle cells of the guinea pig gastric antrum. Together with our previous results showing that G(o) protein is important for activation of ACh-activated NSC channels, our results suggest that I(CCh) might be activated by acetylcholine through m4 subtype as well as m2 and m3 subtypes in guinea-pig stomach.     

Thiophilic interaction chromatography of serum albumins

An investigation of the binding of native and recombinant human serum albumin and bovine serum albumin on three thiophilic gels, PyS, 2S, and 3S was performed. In addition to these proteins, we studied serum albumins from several species such as goat, rabbit, guinea pig, rat, hamster, baboon, and pig. Our results reveal that recombinant human serum albumin (rHSA) binds completely to PyS whereas native human serum albumin and bovine serum albumin bind only partially to PyS. The binding affinities of rHSA, human serum albumin and bovine serum albumin to 2S and 3S gels are less than their binding to PyS. Serum albumins from goat, rabbit, guinea pig, rat, hamster, baboon, and pig bind much stronger to 3S gel than human and bovine serum albumins. The binding of pig and hamster serum albumins is stronger than that of rat, goat, baboon, and rabbit.     

Purification and properties of two protease inhibitors from rat skin inhibiting papain and other SH-proteases.

Two papain inhibitors, I1 and I2, from rat skin extract were purified by affinity chromatography on KSCN-modified papain-agarose gel and by gel filtration on Sephadex G-100. I1 had a molecular weight of 74 000, a pI of 4.6, and it contained 4% of carbohydrates. I1 inhibited papain, ficin, bromelain, rat skin benzoylarginine-2-naphthylamide hydrolase, and to a minor extent, rat skin cathepsin C and bovine trypsin. Bovine chymotrypsin or rat skin cathepsin D were not inhibited and benzoylarginine-2-naphthylamide hydrolase was inhibited only at alkaline pH. An inhibitor corresponding to I1 was present in various rat tissues and also in serum. A similar inhibitor was present in the skin of cat, rabbit, guinea pig, and man. I2 had a molecular weight of 13 400, a pI of 4.9 and it contained no carbohydrates. I2 inhibited all thiol proteases tested, but not trypsin, chymotrypsin, or rat skin cathepsin D. I2 formed an equimolar complex with papain and benzoylarginine-2-naphthylamide hydrolase. I2 was present in rat skin, muscle, lung, and small intestine, but not in kidney, liver, or serum. A similar inhibitor was found in skin extracts of cat, rabbit, guinea pig, and man.     

Topical trans-4-aminomethylcyclohexanecarboxylic acid prevents ultraviolet radiation-induced pigmentation

We have studied the effect of a plasmin inhibitor, trans-4-aminomethylcyclohexanecarboxylic acid (trans-AMCHA), on skin pigmentation induced by ultraviolet (UV) exposure in Weiser-Maples guinea pigs. When guinea pigs are exposed to UV radiation (840 mJ cm-2), skin pigmentation is clearly observed from seven days after exposure and continued to increase to 29 days. Post-exposure applications of 2 and 3% solutions of trans-AMCHA to the exposed regions prevent or inhibit the pigmentation process. When the skin is removed and stained by the Fontana-Masson method, melanin content in the basal layer of UV-exposed epidermis is significantly reduced in the regions to which 2 and 3% trans-AMCHA solutions have been applied, compared with the vehicle control. As plasmin is known to contribute to the release of arachidonic acid (AA) and the production of prostaglandins (PGs), we have examined the effects of trans-AMCHA on AA-induced pigmentation in guinea pig skin. Topical application of trans-AMCHA causes a dose-dependent decrease in AA-induced pigmentation. These results suggest that trans-AMCHA reduces melanocyte tyrosinase activity by suppressing the production of PGs, UV-induced melanogens, through the suppression of the UV-induced increase in epidermal plasmin activity.     

LEVELS OF REDUCED PYRIDINE NUCLEOTIDES AND LENS PHOTODAMAGE

Since most of the known factors that are associated with cataract formation are oxidative in nature, one would expect that a highly reductive environment might arrest or retard the progress of cataract formation. Reduced nucleotides, both NADH and NADPH, are potent reductants with a large negative redox potential of -320 mV. Lenses of certain species contain high levels of these nucleotides, presumably due to the presence of taxon specific crystallins. We have utilized this situation to investigate whether the levels of reduced pyridine nucleotides modulate photo-oxidative damage to the lens. We have monitored the time dependent loss of tryptophan fluorescence upon photodamage for lenses from guinea pig, rabbit and frog (Rana) that contain high levels of pyridine nucleotides and compared with the lenses from rat, Xenopus and a mutant strain of guinea pig that contain significantly lower amounts of these nucleotides. About 75% and 90% of the initial fluorescence intensity is lost in the case of rat and Xenopus lenses, respectively, after a total of 35 min exposure. Rabbit, guinea pig and frog lenses, under identical conditions, show only about 35-40% loss of the initial fluorescence. It appears that the lenses that contain high levels of reduced nucleotides are less susceptible to photodamage. The observed anti-oxidative role of reduced nucleotides in the lenses indicates the possibility of testing reductants (NADPH, NADH and their functional analogues) as potential candidates to therapeutically intervene in the process of cataractogenesis.     

Time-dependent decrease in sunscreen protection against chronic photodamage in UVB-irradiated hairless mouse skin

To determine the time dependence of sunscreen protection against chronic photodamage in hairless mice, the time was varied (0-8 h) between topical sunscreen treatment and UVB radiation exposure. Sunscreen products with labeled sun protection factor (SPF) values of 2, 4 and 8 were evaluated; these values were verified in a guinea pig model for SPF determinations. When applied immediately prior to UVB radiation exposure, these sunscreen products were very effective in prevention of skin wrinkling and tumor formation. Onset of photodamage was delayed, the delay being greater with higher SPF values. However, the sunscreen actives were rapidly lost from the skin surface, and their protective effect diminished strikingly as the time between treatment and irradiation increased. For daily protection against chronic photodamage, this suggests a need for photoprotectants with greater substantivity to achieve a high level of protection throughout the day.