Structure-acute toxicity relationship of aromatic hydrocarbons in mice

The structure-acute toxicity relationship of aromatic hydrocarbons was examined in mice. In all test compounds, the acute toxicity was determined under 2 conditions: control LD₅₀ (LD₅₀-cont) and carbon tetrachloride (CCl₄)-pretreated LD₅₀ (LD₅₀-CCl₄). The CCl₄-pretreatment was done in order to evaluate the toxic potency of compound itself without the influence of metabolism. Both log (1/LD₅₀-cont) and log (1/LD₅₀-CCl₄) were functions of the log P, n-octanol/water partition coefficient, i.e., log (1/LD₅₀-cont) = 0.080 log P − 1.532 and log (1/LD₅₀-CCl₄) = −0.040(log P)² + 0.157 log P − 1.373. Both equations were statistically significant (P < 0.01). The ratio of LD₅₀-cont/LD₅₀-CCl₄ indicated that metabolic activation is more evident in hydrophobic compounds than in hydrophilic compounds. The results suggest that hydrophobicity of the aromatic hydrocarbons plays an important role in determining their acute toxicity.     

Hydrophobicity of β-adrenoceptor blocking agents: Study of correlations between retention in reversed-phase HPLC systems and octanol-water partition constants

The capacity factors (k′) of seven β-adrenoceptor blocking agents in six different reversed-phase HPLC systems have been determined. Octanol-aqueous buffer (pH 7.4) partition constants (P) for these blocking agents were also obtained. By using target factor analysis (TFA), good empirical correlations between the log k′ and log P were derived. The resulting hydrophobicity order agrees well with the metabolic elimination pathways of these drugs.     

Synthesis,Physicochemical Properties,and Cytotoxicity of a Series of 5′-Ester Prodrugs of 5-Iodo-2′-deoxyuridine

Five aliphatic 5-esters of 5-iodo-2deoxyuridine (IDU) were synthesized via an acid chloride alcoholysis reaction. The solubility in pH 7.4 phosphate buffer, lipophilicity as determined by partition experiments in octanol/pH 7.4 buffer, and cytotoxicity of these potential prodrugs were evaluated. The esters showed a 43- to 250-fold increase in lipophilicity and a 1.6- to 14-fold decrease in aqueous solubility relative to IDU. At a concentration of 50 µM, all esters showed reduced cytotoxicity toward uninfected Vero cells relative to IDU.     

A general study of the binding and separation in partition affinity ligand assay. Immunoassay of beta 2-microglobulin

Partitioning in aqueous 2-phase systems was used to separate free and bound ligand in an immunoassay for beta 2-microglobulin. In order to get efficient separation in the phase system, the antibodies were modified to favour their partition in a different phase from that of antigen. However such modification of antibodies significantly decreased their binding capacity. This was overcome by using antibodies bound to previously modified staphylococci, which had proper partitioning behaviour. Alternatively, antibodies conjugated with biotin could be used in combination with modified avidin. This paper presents a method for the evaluation of data from immunoassays whereby 2-phase systems have been used to separate free and bound antigen.     

针灸治疗原发性痛经68例临床观察

采用针刺配隔姜灸治疗原发性痛经 6 8例 ,总有效率 97.0 6 % ,与药物对照组相比 ,P<0 .0 1 ,说明针灸治疗组疗效明显优于药物对照组     

ALPPS与采用不同栓塞材料PVE对肝再生及手术切除率影响研究

目的 比较不同栓塞材料的门静脉栓塞术（PVE）与联合肝脏分隔和门静脉结扎的二步肝切除术（ALPPS）对剩余肝体积（FLR）增长速率的影响,比较各组FLR的增长速率,二期手术切除率、术中数据和术后并发症。方法 采用单中心、前瞻性、非随机对照的对比研究。2014年11月至2019年12月,海军军医大学第三附属医院共126例因FLR不足导致无法切除的肝细胞癌（HCC）或肝内胆管癌（ICC）病人,将其分为4组：ALPPS组及分别采用氰基丙烯酸正丁酯（NBCA）、微球、明胶海绵作为栓塞材料的PVE组。主要终点为FLR增长速率和二期手术切除率。结果 各组的手术切除例数及二期手术切除率分别为：ALPPS组38例（99.4%）,NBCA组32例（76.2%）,明胶海绵组20例（60.6%）,微球组10例（83.3%）。ALPPS组、NBCA组、微球组的FLR增长速率分别为15.1 mL/d,10.0 mL/d和 8.5 mL/d,均高于明胶海绵组（3.7 mL/d）。结论 采用NBCA及微球作为栓塞材料的PVE导致FLR增长速率低于ALPPS,两种栓塞材料的PVE二期手术切除率相当。使用NBCA作为栓塞材料的PVE其FLR增长速率高于微球,且这两种栓塞材料的栓塞效果均优于明胶海绵。     

The Development of a Predictive Method for the Estimation of Flux Through Polydimethylsiloxane Membranes. IV. Application to a Series of Substituted Quinolines

The steady-state flux of 33 substituted quinoline derivatives was determined in polydimethylsiloxane membranes using isopropyl alcohol as the receiver solvent. These diffusants constituted a diverse group of compounds possessing a wide range of hydrophobic, steric, and electronic characteristics. Various parameters representing these physicochemical properties such as cyclohexane–water fragmental constants, molar refractivity, Hammett's constants, intramolecular hydrogen bonding ability, melting point, and mole fraction solubility were employed to develop empirical models capable of relating the rate of diffusion to these characteristics of either the substituent on the quinoline ring or the compound itself.     

Amino Acid Side-Chain Contributions to Free Energy of Transfer of Tripeptides from Water to Octanol

The location of amino acids in soluble or membrane proteins is related to the hydrophobicity of the side chains. Amino acid hydrophobicity values are based upon the thermodynamics of transfer from an aqueous to a nonaqueous environment. However, for certain hydrophilic residues uncertainty exists on the appropriate hydrophobicity values. We have measured the octanol- water partition coefficients (P _o/w) of tripeptides of the sequence N-14-C-acetyl-Ala-JT-Ala-NH-tButyl (AcAlaXAlaNHtButyl), where the central residue X was either Gly , Ala, Phe, Trp, Pro, His, Asp, or Glu. The P _o/w for the tripeptides agreed reasonably well with values calculated by the fragment method of D. J. Abraham and A. J. Leo (Proteins Struct. Func. Gen. 2, 130–152, 1987). The log P _o/w of the uncharged form was 1.6,2.7, and 2.5 greater than the log P _o/w of the ionized form for the His, Asp, and Glu peptide, respectively. The new data on the pH dependence of the ionizable side chains, His, Asp, and Glu, should result in better prediction of the partition coefficient of peptides as a function of pH. The thermodynamic parameters were determined from the temperature dependence of partitioning. In the temperature range studied (2 to 65°C) the transfer of tripeptides from water to octanol was entropy governed except for the ionized peptides. A heat capacity term was necessary to account for the transfer of tripeptides containing non polar residues. The heat capacity change for transfer from water into octanol was –45, –73, –81, and –88 cal/mol K for Ala, Phe, Trp, and Pro peptides, respectively. Peptides containing Gly, His (pH 7.2), and the uncharged forms of Asp, Glu, and His did not show a significant change in heat capacity. The side-chain contribution of the central residue X (G _X) to the free energy of transfer was obtained from the difference between the free energy o f transfer of the peptide containing the central residue X and the Gly peptide; G _X = G _{(AcAlaGlyAlaNHtButyl)} - G _{(AcAlaGlyAlaNHtButyl)}. The relative order of hydrophobicity of the side chains correlated well with previous studies. However, a significant difference was found for the absolute hydrophobicity between the present study and experimental data on N-acetyl amino acid amide derivatives (J. Fauchere and V. Pliska, Eur. J. Med. Chem. 18(4), 369–375, 1983). The G _X values at pH 7.2 were 0, –0.13, –2.19, –2.52,–0.29, –0.16, 3.50, and 3.12 kcal/mol for Gly, Ala, Phe, Trp, Pro, His, Asp, and Glu, respectively. These hydrophobicity values in a tripeptide environment provide suggested values for a hydrophobicity scale.     

丹酚酸组分中各代表性成分药效贡献率的评价及其油水分配系数的整合表征

该实验利用人脐静脉内皮细胞氧化损伤实验、家兔体外凝血4项实验和大鼠心肌缺血实验相结合的方法比较了丹酚酸组分中3个代表性成分的药效活性的差异,并利用CRITIC权重法评价代表性成分的药效贡献率;结果得到丹酚酸组分中代表性成分丹酚酸B、迷迭香酸、丹参素的贡献率分别为28.85%,30.11%,41.04%。采用摇瓶法测定了丹酚酸组分在水以及不同p H缓冲液中的油水分配系数,进一步以质量权重系数和药效贡献率相结合的方法整合表征了该组分整体的油水分配系数,结果表明丹酚酸组分在正辛醇-水/p H 1.2的盐酸溶液/p H 2.0,2.5,5.0,5.8,6.8,7.4,7.8的磷酸盐缓冲液中表观油水分配系数0.32,1.06,0.89,0.98,0.90,0.13,0.02,0.20,0.56。该实验为组分整体性质的表征提供了一定的参考。     

羟基和甲氧基取代苯甲醛在亚硫酸氢钠-乙酸乙酯-水两相中分配系数的测定

 目的 以羟基和甲氧基取代的4个苯甲醛系列化合物为对象,测定它们在亚硫酸氢钠-乙酸乙酯-水两相体系中的分配系数,采用亚硫酸氢钠加成和盐酸酸化的方法研究提取和分离天然醛类化合物的可行性。方法 采用亚硫酸氢钠加成反应,将脂溶性的醛类化合物转化成水溶性的α-羟基磺酸钠衍生物,使醛类化合物从有机相转移到水相。采用高效液相色谱法测定不同比例的亚硫酸氢钠-乙酸乙酯-水两相体系中这些化合物在上相与下相之间的分配系数。采用盐酸酸化和分配萃取,实现α-羟基磺酸钠衍生物还原为原有的醛类化合物。结果 醛类化合物的分配系数,随着亚硫酸氢钠-乙酸乙酯-水两相体系中亚硫酸氢钠比例的增加急剧减小,并达到平衡。结论 通过亚硫酸氢钠加成反应和盐酸酸化,使脂溶性的醛类化合物经水溶性的α-羟基磺酸钠衍生物还原到原始的醛类化合物,经两次萃取,可以实现天然产物中醛类化合物专属性的提取和分离。