人参皂苷Rb1对皮肤胶原代谢的影响

目的 将人参皂苷Rb1作用于人成纤维细胞,观察其对皮肤胶原代谢的作用.方法 人成纤维细胞在不同浓度的Rb1中的增殖情况,结果 用MTT法测定.消化法检测羟脯氨酸含量.酶联免疫吸附测定法测定细胞分泌Ⅰ型前胶原、基质金属蛋白酶-1(Matrix metalloproteinase-1,MMP-1)、基质金属蛋白酶抑制酶-1(Tissue inhibitor of metalloproteinase-1,TIMP-1)的蛋白表达情况.结果与空白组比较,人参皂苷Rb1能显著提高细胞增殖水平,羟辅氨酸含量、Ⅰ型前胶原及TIMP-1的蛋白质表达量(P<0.05),显著降低MMP-1蛋白质表达量(P<0.05).结论 皮肤胶原代谢受人参皂苷Rb1调节.这表现在能促进HSF增值;通过影响成纤维细胞的蛋白质的表达促进胶原合成并抑制胶原降解,结果提高胶原蛋白总量.     

以组织蛋白酶K为靶点的新药筛选

组织蛋白酶K(cathepsin K)是半胱氨酸蛋白酶家族的成员，它和组织蛋白酶S、L和B有很高的同源性。人类破骨细胞中大量选择性表达组织蛋白酶K，并已证明组织蛋白酶K是参与骨胶原降解的主要酶，在骨代谢中起很大的作用，为此，组织蛋白酶K已成为治疗骨质疏松症的重要分子靶标。近年来对组织蛋白酶K的结构与功能的研究，以及以该酶为靶点的抗骨质疏松新药筛选研究已成为新药研究领域的一个热点。本文就组织蛋白酶K在骨代谢中的作用以及组织蛋白酶K抑制剂筛选模型的研究进展进行综述。     

改良GC法测定血中氯磺丙脲及其在临床和药理上应用的评价

本文在Sabih 法的基础上,改进并简化了分离和测定血中微克量氯磺丙脲(Chlorpropamide,Clp)的GC法,以使其适用于临床药理,特别适用于对Clp 的药物动力学评价。主要的改进包括采用直径较大的层析柱,     

蛋白酶抑制剂利托那韦、沙奎那韦和印地那韦对细胞色素P450同工酶的不同抑制作用

人类免疫缺陷病毒1型(HIV-1)的3个主要基因编码的多聚蛋白质,其翻译的后加工过程是由细胞或病毒编码的蛋白酶水解完成的。如果这些蛋白酶丧失了活性,就可以产生不成熟的、无传染性的病毒颗粒,所以HIV病毒编码的蛋白酶抑制剂可以起到抗HIV的作用。目前,该类化合物的研究已经得到很大程度的重视。本研究通过体外实验观察了3个HIV蛋白酶抑制剂利托那韦(ritonavir)、沙奎那韦和印地那韦(indinavir)对人肝细胞微粒体中细胞色素同工酶催化代谢的抑制效应。肝微粒体从6名肾移植供者的正常肝脏中制取,细胞色素P450同工酶CYP1A2、CYP2C9、C…     

豆粕的不同酶解液发酵苏云金芽孢杆菌对Zwittermicin A产量的影响

目的 研究培养基中豆粕所含蛋白质的不同存在形式对zwittermicin A产量的影响.方法 豆粕经过3种不同的复合蛋白酶(碱/中蛋白酶、中性蛋白酶、酸/中蛋白酶)处理后形成了蛋白质、寡肽和氨基酸含量均不同的3种酶解液,即DPI,DP2和DP3.以苏云金芽孢杆菌库斯塔克亚种(Bacillus thuringiensis sp.kurstaki D1-23)为菌种,分别将这3种豆粕酶解液作为其氮源进行发酵.结果 从含有DP1的培养基D-1 中获得的苏云金芽孢杆菌生物量最低;含有DP2的培养基D-2中的zwittermicin A含量最高;从含有DP3的培养基D-3中得到的生物量最大.结论 氮源的存在形式不同,对Bacillusthuringiensis sp.turstaki D1-23 菌体繁殖和其次级代谢产物zwittermicin A的合成有不同影响.     

基质金属蛋白酶与类风湿关节炎

细胞外基质在维持正常组织结构与功能及细胞生长、分化过程中起非常重要的作用.它处在不断的代谢更新、降解重塑的动态平衡中.大量研究表明,该动态平衡的破坏会导致多种疾病,包括结缔组织病.在此代谢平衡调节中,基质金属蛋白酶(matrix metalloproteinase,MMPs)和金属蛋白酶组织抑制剂(tissue inhibitors of metalloproteinase,TIMP)两个酶系统的作用尤为重要.     

静脉滴注氨基酸注射液致过敏性休克3例

氨基酸类药具有促进人体蛋白质代谢正常,纠正负氮平衡,补充蛋白质,加快伤口愈合的作用。主要用于蛋白质摄入不足,吸收障碍等氨基酸不能满足机体代谢需要的     

前导序列工程

在传统的蛋白质工程中,为了改变酶的特性,常采用诱变等方法在蛋白酶结构域中引入突变.在前导序列调节蛋白折叠机制的基础上,文章介绍了一种新的蛋白质工程技术--"前导序列丁程".前导序列工程是指当前导序列发生突变时,同一种多肽链可以折叠成具有不同高级结构、稳定性或特异性改变的构型.前导序列工程不仅是研究蛋白质折叠机理的重要丁具.更是创造新型蛋白酶的一种十分有前途的新技术.文章以枯草杆菌蛋白酶为例,介绍了前导序列工程的意义与应用.例如.枯草杆菌蛋白酶在突变前导序列作用下可以得到底物特异性改变的酶,并且可以提高自动处理效率.-个枯草杆菌蛋白酶同族的前导序列可以作为变性枯草杆菌蛋白酶折叠的分子内伴侣帮助其折叠.     

高血压患者循环中基质金属蛋白酶-9的研究现状

基质金属蛋白酶(MMPs)是一个家族的锌依赖性蛋白酶,基质金属蛋白酶-9(matrix metalloproteinases-9,MMP-9)又称明胶酶,是金属蛋白酶家族中的一员,它参与细胞外基质(Extracellular matrix,ECM)胶原的代谢,在许多心血管疾病的发生、发展过程中发挥重要作用,如参与心肌梗死后心室的重构和高血压引起的心室重构等.     

细菌ClpP蛋白酶功能及其抗菌药物靶点的研究进展

摘要：ClpP(Casein lytic proteinase P)是一种广泛存在于真核细胞和原核生物中的丝氨酸蛋白酶，可与多种类型AAA+ (ATPase associated with various cellular activity)超家族ATP酶组成多种ClpP蛋白酶复合物，其主要功能是清除或降解细菌胞内合成不当、受损伤、变性聚集或无用的蛋白，并维持正常代谢和压力刺激下胞内蛋白质的动态平衡。近年研究表明，细菌ClpP可协助病原菌在宿主体内生存、繁殖和播散，ClpP在细菌致病过程中发挥重要作用，其相关致病机制也受到广泛关注。近年，细菌对抗生素耐药性不断增强，已严重威胁人类健康，ClpP蛋白酶因其独特的蛋白水解作用而成为抗菌药物研究的新靶点。本文综述了ClpP在不同病原体中的结构、分子功能和不同作用以及相应药物开发方面的研究进展。     

Recent advances in Clp protease modulation to address virulence,resistance and persistence of MRSA infection

The Clp protease is an AAA⁺ protease that executes abnormally folded or malfunctioning proteins, and has an important role in producing virulence factors, forming biofilms or persisters and developing methicillin-resistant Staphylococcus aureus (MRSA). Recent studies showed that Clp protease controls virulence via agr signaling and degrades antitoxins of the toxin–antitoxin system to modulate the formation of persisters and biofilms. In this review, we focus on recent developments concerning the virulence and persistence regulatory pathways and resistance-related mechanism of Clp protease in S. aureus, with an overview of the Clp modulators developed to treat MRSA infection.     

Disposition of recombinant human interleukin-10 in subjects with various degrees of renal function.

The pharmacokinetics of intravenously administered recombinant human interleukin-10 (rHuIL-10) were evaluated in 18 subjects with creatinine clearances (Clcr) between 2.7 and 116.7 mL/min/1.73 m2. Serum samples for rHuIL-10 were obtained over a 48-hour period after a single 25 micrograms/kg i.v. bolus infusion. AUC, total body clearance (Clp), and steady-state volume of distribution (Vdss) were derived by compartmental methods. Analysis of serum concentrations showed statistically significant group differences for log-transformed AUC and original scale Clp (p < 0.01). The AUC and effective half-life increased, while the mean Clp of rHuIL-10 decreased as renal function declined. A linear relationship between AUC and Clcr as well as Clp and Clcr demonstrates that the disposition of rHuIL-10 is altered in subjects with renal insufficiency. No serious adverse events were noted.     

Clinical pharmacokinetics of pinacidil, a potassium channel opener, in hypertension

Pinacidil is a potassium channel opener that decreases blood pressure by reducing peripheral arterial resistance. In two multicenter trials, we studied the concentrations and apparent clearance of pinacidil (406 patients) and concentrations of its pyridyl-N-oxide metabolite (147 patients). Responding patients had plasma samples collected hourly for 12 hours on 2 occasions after weeks to months of treatment. Pinacidil dose was titrated from 12.5 to 75 mg b.i.d. The peak concentration of pinacidil and N-oxide and the area under the concentration-time curve (AUC) were proportional to the dose of pinacidil, with an average pinacidil concentration of 268 micrograms/L (1.02 microM) and N-oxide concentration of 172 micrograms/L (0.65 microM) for every 1 mg/kg pinacidil administered. Clearance of pinacidil (Clp = Dose/AUC) was 31 L/hr in patients younger than 45 years and 27 L/hr in those older than 60. Clp was significantly smaller in white patients compared with other races (Clp = 28 vs. 34 L/hr). Clp was significantly less in patients taking hydrochlorothiazide (27 vs. 31 L/hr) and greater in smokers (33 vs. 29 L/hr). Concomitant propranolol use did not influence Clp.     

Influence of age, sex, pregnancy and protein-calorie malnutrition on the pharmacokinetics of salicylate in rats

The influence of age, sex, pregnancy and protein-calorie malnutrition (PCM) on the plasma t1/2, plasma clearance (Clp) and apparent volume of distribution (Vd) of sodium salicylate (62 mumol kg-1) was determined in Sprague-Dawley rats. Female and male rats of five different age groups (ages in weeks: pups 1, weanling 3, young 8-9, adult including pregnant 14-15, old 56-60) including three age groups with PCM (8-9, 14-15 and 56-60 weeks old) were used. Plasma and urinary salicylates were assayed by h.p.l.c. Plasma t1/2 was longer and Clp smaller in pups than in weanling and young rats and comparable to values for old rats; Vd of salicylate in pups was larger than in any other group of rats. Plasma t1/2 was longer and Clp as well as Vd of salicylate were smaller in adult females than in males of comparable age. Relative to nonpregnant adult females, Vd of salicylate in pregnant rats was larger but plasma t1/2 and Clp were unchanged. In all groups of rats studied, PCM decreased the plasma t1/2 and increased the Clp of salicylate; Vd was unchanged. Changes in salicylate pharmacokinetics were not due to any differences in serum protein-salicylate binding or to serum testosterone levels. Ovariectomy decreased the plasma t1/2 of salicylate but castration of male rats had no significant effect. Administration of testosterone to ovariectomized female rats exerted no significant effect on salicylate pharmacokinetics. It is concluded that the physiological state and the nutritional status can modify salicylate pharmacokinetics; in so far as the rat model reflects the human situation, these variables should be taken into account for a rational salicylate therapy.     

Pharmacokinetics and biliary excretion of bromosulphophthalein, [3H]-ouabain and [3H]-taurocholic acid in rats with glycerol-induced acute renal failure

The pharmacokinetics and biliary excretion of bromosulphophthalein (BSP), ouabain and taurocholic acid (TChA) have been studied in rats with glycerol-induced acute renal failure (ARF). In rats with ARF, the hepatic uptake and initial biliary excretion of BSP were decreased. In addition, the rate of BSP conjugation with glutathione by rat liver homogenates was also decreased. This latter change may contribute to the initial decrease in the biliary excretion of BSP. No change was found in the hepatic uptake and biliary excretion of ouabain, but the area under the concentration-time curve was increased and the plasma clearance (Clp) decreased in rats with ARF. This decrease in Clp was not due to reduced renal excretion. The decreased Clp of ouabain in rats with ARF may come from reduced tissue binding and a concomitant decrease in its volume of distribution (Vd). The hepatic handling of TChA appeared unaltered in ARF, but the rate constant for the terminal part of the concentration-time curve (beta) was decreased. This change probably resulted from a large increase in Vd in rats with ARF. It is concluded that the decreased uptake of BSP was not due to a non-specific disturbance of hepatocyte function in ARF because the hepatic handling of ouabain and TChA were unaltered.     

The pharmacokinetics of 125I-atrial natriuretic factor in anaesthetized rats. Effects of neutral endopeptidase inhibition with candoxatrilat and of ANF-C receptor blockade.

The effects of candoxatrilat (cis-4-([2-carboxy-3-(2-methoxyethoxy)propyl]-1-cyclopentanecarbonyla mino)- 1-cyclohexane carboxylic acid) and the ring-deleted atrial natriuretic factor (ANF) analogue C-ANF4-23 (des[Gln18, Ser19, Gly20, Leu21, Gly22]ANF4-23-NH2) on the clearance of (3-[125I]iodotyrosyl28)ANF (125I-ANF) were studied in both intact and nephrectomized anaesthetized rats. HPLC analysis was used to verify that the 125I-labelled material isolated by solid phase extraction of rat plasma was intact ANF. In intact animals, clearance of 125I-ANF was biphasic with a T1/2 alpha of 17 sec and T1/2 beta of 95 sec. Volume of distribution (Vd) was 564 mL/kg and plasma clearance (Clp) 248 mL/min/kg. Candoxatrilat, over the dose range 0.01-10 mg/kg i.v., increased T1/2 beta (by a maximum of 56%) and decreased Clp (by up to 52%) with no effect on T1/2 alpha or Vd. C-ANF4-23 (10 micrograms/kg+1 microgram/kg/min i.v.) reduced Vd (by 57%) and Clp (by 54%) with no effect on T1/2 beta, whilst abolishing the T1/2 alpha phase in over 50% of animals. Increasing the dose of C-ANF4-23 did not increase the effect on any of these parameters, apart from a small increase in T1/2 beta. Combining the two agents resulted in a substantial decrease in Clp (76%) whilst the reduction in Vd and increase in T1/2 beta were comparable to those seen with C-ANF4-23 and candoxatrilat alone, respectively. In nephrectomized rats, the pharmacokinetics of 125I-ANF and the changes induced by candoxatrilat were similar to those observed in intact animals, whilst the effects of C-ANF4-23 alone were greater than in intact animals. The combination of C-ANF4-23 and candoxatrilat again produced a substantial increase in T1/2 beta (153%) and decreases in Vd (55%) and Clp (78%) in nephrectomized animals, although these changes could not be distinguished from those seen in intact animals treated with the same combination. Our studies indicate that neutral endopeptidase and ANF-C receptors are both major, and approximately equal, clearance mechanisms for 125I-ANF, together accounting for at least 75% of the total clearance of this peptide in the rat.     

Famotidine disposition in children and adolescents with chronic renal insufficiency

The pharmacokinetics of intravenous famotidine (0.5 mg/kg, maximum 20 mg) were evaluated in 18 pediatric patients (ages 1-18 years) with stable, chronic renal insufficiency. Subjects were stratified by calculated creatinine clearance (Clcr) into mild (Clcr > or = 50 to < 90 mL/min/1.73 m2), moderate (Clcr > or = 25 to < 50 mL/min/1.73 m2), and severe (Clcr < or = 10 mL/min/1.73 m2) renal insufficiency groups. Significant differences between the mild, moderate, and severe groups were found for elimination rate (Kel), apparent elimination half-life (t1/2), area under the curve (AUC), and total plasma clearance (Clp) (p < 0.01). Famotidine renal clearance (Clr) was found to be significantly different between the mild and severe groups (p < 0.05). A linear relationship was observed between Clcr and Clp (p < 0.0001; R2 = 0.70). No significant differences in nonrenal clearance (Clnr) were found between groups; however, Clnr as a percentage of Clp was significantly different in the severe group (92.9% +/- 7.3% Clnr) compared to the combined mild and moderate groups (21.9% +/- 45.6% Clnr) (p < 0.05). It was concluded that the pharmacokinetics of famotidine are significantly altered in children with chronic renal insufficiency; accordingly, dosing should be based on glomerular filtration rate (i.e., Clcr).     

Pharmacokinetics of heparins differing in mean molecular weight using a Xa amidolytic and Heptest clotting method

The pharmacokinetics of heparins ranging in mean MW from 23,000 to 4,500 were determined using a new clotting test (Heptest) and an anti-Xa, amidolytic method. No significant difference between the two methods was observed in the calculated values for distribution volume (Vd), halflife (t1/2), plasma clearance (Clp) or area under the concentration-time curve (AUC) for heparins of any MW. However, when pharmacokinetic parameters calculated from both methods were compared as a function of MW, significant differences were observed. Values for t1/2 averaged from the two methods increased with decreasing MW. The t1/2 values were 30, 35, and 50 min for the 23,000, 13,300, and 5,100 MW fractions, respectively. Similarly, AUC increased with decreasing MW while Clp decreased. All heparins were observed to have VdS approximating the plasma compartment. A slightly larger Vd was observed with the lowest MW heparin.     

Disposition of guanadrel in subjects with normal and impaired renal function

The disposition of a single 25 mg oral dose of guanadrel was evaluated in 22 subjects with various degrees of renal function. The terminal elimination half-life was significantly prolonged in subjects with a creatinine clearance (ClCr) less than 30 mL/min/1.73 m2 (19.2 +/- 16.8 h) compared to 3.7 +/- 1.9 h in subjects with a ClCr greater than 80 mL/min/1.73 m2. Apparent total body clearance (Clp/F) was also progressively lower in the patients with decreased renal function and the decline was significantly correlated with ClCr (Clp/F = 0.0294 + 0.0236 Clcr, r = 0.74, P = 0.002). Renal clearance and apparent nonrenal clearance also declined as creatinine clearance decreased, and both were significantly correlated with the observed ClCr. Apparent volume of distribution averaged 11.5 +/- 8.9 L/kg and did not differ in patients with decreased renal function compared to those with normal renal function. Thus, the disposition of guanadrel is significantly altered in the presence of renal insufficiency and dosage adjustments may be necessary, especially in patients with ClCr less than 50 ml/min.     

Investigations upon collagen metabolites in blood serum and urine of patients with acquired valvular heart disease

In 45 patients suffering from acquired valvular heart disease (a.v.h.d.) and in 20 controls blood serum levels of copper (Cu2+), ceruloplasmin (Clp), hydroxyproline (Hypro), hydroxylisine (Hyliz), collagen-like protein (Col-p), and daily urine excretion of Cu2+, Hypro, Hyliz and glycosamino-glicans (GAG) were determined. The comparison of the obtained mean values has shown that blood serum levels of Cu2+, Clp, Hypro, Hyliz, Col-p in the studied patients were statistically significantly higher than those found in controls, and the values of daily urine excretion of Cu2+, Hypro, Hyliz, GAG behaviour were similar. There were no significant differences between active and inactive processes and between infective and rheumatic endocarditis excluding GAG urine excretion. These elevated collagen degradation products provide evidence for disturbed collagen metabolism and confirm our previous biochemical, histopathological and ultrastructural examinations of connective tissue in patient with a.v.h.d. They also indicate that general collagenopathy might be the primary cause of a.v.h.d.