变价态唐松草新碱—PVC膜离子选择电极的研制及解离常数的测定

本文研制了以四苯硼—唐松草新碱缔合物为电活性物质的变价态唐松草新碱—PVC膜电极。电极膜按电活性物质:PVC:DBP为1:8:8组成。该电极在pH 5.0～6.0,Ⅰ=0.05的NaCl—HCl溶液中Nernst响应范围为1×10^-3～1×10^-5mol/L。电极斜率为58.2 mV/logc。检测限为2.5×10^-6mol/L。用直接电位法考察了TDH⁺,TDH₂CF⁺⁺共存时溶液pH和电极斜率S的关系。用S—pH关系,测定了25℃,Ⅰ=0.05时的Ka₁值为(2.5±0.2)×10^-4,用E—pH关系,测定了25℃,Ⅰ=0.05时的Ka₂值为(8.1±0.9)×10^-8。     

Choline acetyltransferase immunoreactivity in neuritic plaques of Alzheimer brain

We have observed dystrophic choline acetyltransferase (ChAT)-positive processes surrounding the amyloid core of neuritic plaques in human neocortex, amygdala and hippocampus, using a polyclonal anti-human ChAT antiserum. These data, and those from studies of the aged monkey by other investigators, provide a morphologic counterpart for the biochemical abnormality of the cholinergic system in Alzheimer's disease and senile dementia of the Alzheimer type.     

普鲁卡因选择性涂丝电极稳定性的研究

涂丝电极的应用已很广泛,但其稳定性差限制了它的进一步推广应用。本文找出普鲁卡因涂丝电极稳定性差的原因,制备了以聚乙烯醇(含盐酸普鲁卡因)为内参的Ag-Agcl丝涂(PVC)膜电极,其稳定性大为提高,并有良好的响应性能。     

Biosynthesis and secretion of factor VII, protein C, protein S, and the Protein C inhibitor from a human hepatoma cell line

Using specific radioimmunoassays, 8 day cultures of Hep G2 cells were shown to contain in their supernatants 16, 74, and 828 ng/mL and in their cell lysates, 8, 55, and 48 ng/2 X 10(8) cells of factor VII, protein C, and protein S, respectively. These proteins and the protein C inhibitor were functionally active, and each of these activities was neutralized by their respective polyclonal antibodies. Although vitamin K had a modest effect, warfarin decreased the activity of secreted factor VII, protein C, and protein S by 50% to 90%. Protein C and protein S antigens were reduced three- to fourfold by warfarin. The protein C inhibitor antigen and activity were unaffected by vitamin K or warfarin treatment. Intrinsic labeling and immunoprecipitation indicated that factor VII, protein S, and the protein C inhibitor were secreted as 52,000, 77,000, and 58,000 molecular weight (mol wt) proteins, respectively. Protein C was secreted as a single-chain protein of about 65,000 mol wt, indicating that all of the vitamin K- dependent proteins are translated and secreted as single-chain molecules. Each of the four proteins studied represented their plasma protein counterparts structurally, functionally, and immunochemically. Thus, all of the known soluble components of the protein C pathway are produced by liver parenchymal cells.     

Pharmacokinetics of recombinant interleukin 2 in humans

This report summarizes the pharmacokinetics in humans of recombinant interleukin 2 (IL-2) given as an i.v. bolus, i.v. or i.p. infusion, and i.m. or s.c. injection. Immediately after an i.v. bolus the serum IL-2 level equals the dose divided by the plasma volume, in a typical human 650 units/ml for a dose of 10(6) units/m2. The level initially decreases with a half-life of 12.9 min, followed by a slower phase with a half-life of 85 min out to 4 h after the bolus. The median steady state level during an i.v. infusion of 10(6) units/m2 over 6 h is 41 units/ml. A clearance rate of approximately 120 ml/min is obtained from either the i.v. bolus or infusion data and is consistent with the renal filtration being the major route of clearance. Serum levels remain fairly constant for about 8 h after s.c. or i.m. injection but are approximately 2% of the level seen immediately after an i.v. bolus. The area under the time-concentration curve suggests that about 30% of the IL-2 activity is transported from the site of an i.m. injection to the blood. After i.p. infusion IL-2 is only slowly transported to the blood. The median serum IL-2 levels are 430-fold lower than levels in the i.p. fluid and decrease with a median half-life of 6.3 h.     

唐松草新碱水溶液的氧化降解动力学研究

本文研究了唐松草新碱在水溶液中的氧化降解动力学。考查了pH值、离子强度、温度和氧含量的影响,水溶液中的氧化降解速率常数由荧光法测定。结果表明,唐松草新碱在过量氧存在下,其氧化降解反应服从假一级反应动力学方程式,速率常数可由下式表示:其速率常数主要受介质的pH值和氧含量的影响,在pH 7.2条件下没有观测到原盐效应。     

Kinetic and inactivation studies of recombinant Drosophila choline acetyltransferase

A cDNA for Drosophila choline acetyltransferase (ChAT) was expressed in E. coli and the recombinant enzyme partially purified. Kinetic analysis yielded the following constants for the recombinant enzyme; KmAcCoA = 29 microM, KmCoA = 25 microM, Kmcholine = 330 microM, and Kmacetylcholine = 2 mM. The recombinant Drosophila enzyme, like the enzyme from other species, exhibited an increase in activity as a function of increased salt concentration. Chemical modification studies using dithio-bis-nitro-2-carboxylate, butanedione, and diethylpyrocarbonate showed that the recombinant enzyme contains active site cysteine, arginine, and histidine residues. These studies demonstrate that the recombinant Drosophila ChAT possesses the same catalytic properties as the enzyme from a variety of other sources.