In vitro and in vivo antipicornavirus activity of some phenoxypyridinecarbonitriles.

Nineteen phenoxypyridinecarbonitriles were initially evaluated for their in vitro activity against rhinoviruses (RV) 1A, 2, and 64 and coxsackievirus (Cox) A21 and for their oral prophylactic and therapeutic activity in Swiss albino mice challenged with Cox A21. On the basis of the results of these studies, one compound, 6-(3,4-dichlorophenoxy)-3-(ethylthio)-2-pyridinecarbonitrile, was selected for further evaluation. Expanded in vitro spectrum of activity studies showed that the MIC causing a 50% reduction in viral cytopathic effect in infected cultures (MIC50) was 3.0 micrograms/ml or less against 11 of 20 RV serotypes tested. The compound was only moderately active (MIC50, 5 to 7 micrograms/ml) against four of the RV serotypes evaluated, while RV 4, 5, 8, 13 and Hank's were relatively resistant to compound inhibition. Of the nine enteroviruses studied, only Cox A21, echovirus 12, poliovirus 2, and enterovirus 70 were inhibited at compound concentrations of less than 2.0 micrograms/ml. The compound provided significant protection to mice infected with a normally lethal dose of Cox A21 when administered in a single oral dose of 150 mg/kg (P less than 0.01) and during a regimen of continuous oral doses of 37.5 mg/kg per day (P less than 0.001). Mechanism of action studies indicated that the compound inhibited picornavirus uncoating or some earlier virus-host cell-associated event.     

In vitro effect of trifluoperazine on human lymphocytes

Trifluoperazine, a phenothiazine group of tranquilizer was studied for its chromosome damaging effect in human lymphocyte cultures. The cells were treated with 10, 15 and 20 micrograms/culture of trifluoperazine for 24, 48 and 72 hours. A high incidence of chromatid breaks and gaps was observed after 48 and 72 hours treatment. The study revealed that the drug acts mostly on the late S and G2 phase of the cell cycle.     

孕酮对体外培养人成骨细胞增殖和分化的促进作用

目的:探讨孕酮对正常成人成骨细胞的作用,验证孕激素治疗绝经后骨质疏松症的假设机制。方法:以正常成年女性松质骨分离培养的人成骨细胞为对象,用10-10,10-8,10-6M孕酮干预。四甲基偶氮唑蓝法检测细胞增殖情况;半定量反转录聚合酶链反应和免疫印记法测定孕激素受体mRNA和蛋白质表达;半定量RT-PCR测定c-fos,c-jun和骨钙素基因表达。结果:与对照组相比较,10-10,10-8,10-6M孕酮增加人成骨细胞增殖达9.8%,23.0%和32.8%。孕酮不影响孕激素受体mRNA和蛋白质表达,但可增加c-fos,c-junmRNA表达,分别为5.4%,15.3%,35.5%和7.2%,20.1%,40.3%。孕酮增加骨钙素mRNA表达为12.2%,23.7%和45.5%。结论:孕酮可促进人成骨细胞的增殖和分化,可用于治疗绝经后骨质疏松症。     

啤酒对血清酶活性影响的体内外实验

目的:观察体内外实验中受试者饮用啤酒后各种血清酶活性的变化情况。设计:观察对比实验。单位:泰山医学院基础医学研究所。对象:实验于2005-03/04在泰山医学院基础医学研究所完成。选择泰山医学院学生17名,年龄19～35岁,包括本科生和研究生,实验前均签署同意书。方法:①体内实验:受试者统一正常饮食后3h采静脉血3mL,作为对照。然后立即口服啤酒4mL/kg,分别于15,30,45,60,90,120,180min后各采血3mL,测定血液中丙氨酸氨基转移酶、天冬氨酸氨基转移酶、γ-谷氨酰转肽酶、碱性磷酸酶、肌酸激酶、乳酸脱氢酶、淀粉酶、脂肪酶活性的变化。②体外实验:选取17份新鲜受试者血清,分别加入两个试管中,每管0.5mL。对照管加入20μL生理盐水;测定管中加入20μL啤酒溶液,观察啤酒对以上各种酶活性的直接影响。主要观察指标:体内外实验中血清丙氨酸氨基转移酶、天冬氨酸氨基转移酶、γ-谷氨酰转肽酶、碱性磷酸酶、肌酸激酶、乳酸脱氢酶、淀粉酶及脂肪酶的活性。结果:纳入17名学生,全部进入结果分析,无脱落。①体内实验:啤酒可显著降低血清天冬氨酸氨基转移酶活性(418.08±58.68,383.41±63.01)nkat/L,显著升高血清碱性磷酸酶活性(3678.57±436.25,3962.96±400.91)nkat/L(χ2=19.00～20.00,P<0.01),其余酶活性均有不同程度的升高。②体外实验:啤酒在体外对各种酶活性均有一定程度的抑制作用。结论:啤酒在体内外对酶活性均有一定影响,从而影响机体代谢,过量饮用会影响健康。在常规血清酶学检测中,应避免患者饮用啤酒所造成的干扰,以确保实验结果的准确可靠。     

啤酒对血清酶活性影响的体内外实验

背景：啤酒对血清酶活性的直接影响尚未见报道。目的：观察体内外实验中受试者饮用啤酒后各种血清酶活性的变化情况。 设计：观察对比实验。 单位：泰山医学院基础医学研究所。 对象：实验于2005-03／04在泰山医学院基础医学研究所完成。选择泰山医学院学生17名，年龄19-35岁，包括本科生和研究生，实验前均签署同意书。 方法：①体内实验：受试者统一正常饮食后3h采静脉血3mL，作为对照。然后立即口服啤酒4mL／kg，分别于15．30，45，60，90，120，180min后各采血3mL，测定血液中丙氨酸氨基转移酶、天冬氨酸氨基转移酶、γ-谷氨酰转肽酶、碱性磷酸酶、肌酸激酶、乳酸脱氢酶、淀粉酶、脂肪酶活性的变化。②体外实验：选取17份新鲜受试者血清，分别加入两个试管中，每管0．5mL。对照管加入20μL生理盐水；测定管中加入20μL啤酒溶液，观察啤酒对以上各种酶活性的直接影响。 主要观察指标：体内外实验中血清丙氨酸氨基转移酶、天冬氨酸氨基转移酶、γ-谷氨酰转肽酶、碱性磷酸酶、肌酸激酶、乳酸脱氢酶、淀粉酶及脂肪酶的活性。结果：纳入17名学生，全部进入结果分析，无脱落。①体内实验：啤酒可显著降低血清天冬氨酸氨基转移酶活性（418．08&;#177;58．68，3834l&;#177;63.01）nkat／L，显著升高血清碱性磷酸酶活性（3678．57&;#177;436．25，3962．96&;#177;400.91）nkat／L（x^2=19．00&;#177;20．00，P〈0．01），其余酶活性均有不同程度的升高。②体外实验：啤酒在体外对各种酶活性均有一定程度的抑制作用。 结论：啤酒在体内外对酶活性均有一定影响，从而影响机体代谢，过量饮用会影响健康。在常规血清酶学检测中，应避免患者饮用啤酒所造成的干扰，以确保实验结果的准确可靠。     

In vitro and in vivo studies of the effect of artemether on Schistosoma mansoni.

To determine whether artemether, a derivative of the antimalarial agent qinghaosu, is therapeutically active against Schistosoma mansoni, we determined the in vitro, in vivo, and histopathologic effects of the drug on S. mansoni worms. In vitro, toxic effects of artemether on S. mansoni were not seen at concentrations of less than 100 micrograms/ml. However, in vivo, 30 and 50% reductions in the lengths of male and female worms, respectively, were observed 14 days after treatment. By 56 days worm dimensions had returned to control values. Similar reversible effects on male testes and female ovaries were seen. In vivo, a single oral dose of artemether (300 mg/kg) induced a shift of worms towards the liver within 8 h after treatment. By 3 and 14 days after treatment, 99 and 76%, respectively, of worms were still in the liver. In vivo, the therapeutic effect of artemether on adult S. mansoni treated on day 56 after infection was modest. Doses as high as 1,200 mg (200 mg/kg per day, six doses) resulted in a worm reduction rate of only 39%. However, in infected mice treated on day 14 or 21 after infection, worm reduction rates of 83 to 98% were obtained. Thus, artemether exhibited modest in vitro and in vivo activities against adult S. mansoni but was twofold more active against 2- to 3-week-old liver-stage parasites.     

In vitro and in vivo ciprofloxacin pharmacokinetics in human neutrophils.

Early in vitro investigations have shown that ciprofloxacin is concentrated within human neutrophils (polymorphonuclear leukocytes [PMNs]) at between 3 and 11 times the extracellular concentration. The elution of ciprofloxacin from cells is relatively rapid when the extracellular concentration is reduced. In order to estimate the in vivo intracellular penetration of ciprofloxacin and to determine its intracellular pharmacokinetics, PMNs were recovered from blood samples drawn from healthy volunteers at different times during a 24-h period after they were given a 750-mg oral dose. High-performance liquid chromatographic determination of ciprofloxacin in serum and cells showed that the intracellular/serum ratio was 3.7 at 1.5 h (maximum concentration of drug in serum), 5.7 at 12 h, and 20 at 24 h. The area under the curve ratio was 3.73. The mean elimination half-lives of ciprofloxacin were 3.7 and 6.2 h in serum and PMNs, respectively. These data show that in vivo findings are in agreement with in vitro findings. The large uptake of ciprofloxacin by PMNs combined with a prolonged intracellular half-life described under the conditions of human therapy should provide the basis for the use of ciprofloxacin in infections caused by susceptible intracellular bacteria.     

The effect of experimental rat tumours on progesterone binding in the host liver

1. The effect of the R3230 AC rat mammary adenocarcinoma on progesterone binding in the liver of female F344 rats has been studied. The growth of the transplanted tumour shows a positive correlation with increased binding of progesterone to the endoplasmic reticulum. 2. Both total binding rate and saturation level in the formation of specific progesterone microsomal receptor complex are increased. 3. This is paralleled by an elevated progesterone content of microsomal membranes. 4. In contrast, nonspecific progesterone binding in the microsomes is reduced. These results may represent a paraneoplastic change.     

In vivo electrical conductivity of hepatic tumours

Knowledge of electrical tissue conductivity is necessary to determine deposition of electromagnetic energy and can further be used to diagnostically differentiate between normal and neoplastic tissue. We measured 17 rats with a total of 24 tumours of the K12/TRb rat colon cancer cell line. In each animal we measured in vivo hepatic tumour and normal tissue conductivity at seven frequencies from 10 Hz to 1 MHz, at different tumour stages between 6 and 12 weeks after induction. Conductivity of normal liver tissue was 1.26 +/- 0.15 mS cm(-1) at 10 Hz, and 4.61 +/- 0.42 mS cm(-1) at 1 MHz. Conductivity of tumour was 2.69 +/- 0.91 mS cm(-1) at 10 Hz, and 5.23 +/- 0.82 mS cm(-1) at 1 MHz. Conductivity was significantly different between normal and tumour tissue (p < 0.05). We determined the percentage of necrosis and fibrosis at the measurement site. We fitted the conductivity data to the Cole-Cole model. For the tumour data we determined Spearman's correlation coefficients between the Cole-Cole parameters and age, necrosis, fibrosis and tumour volume and found significant correlation between necrosis and the Cole-Cole parameters (p < 0.05). We conclude that necrosis within the tumour and the associated membrane breakdown is likely responsible for the observed change in conductivity.     

Ultrasonic irradiation of mouse tissues in vivo and human amniotic cells in vitro

Recently published results have been substantiated by enlarging the group sizes of mice subjected to whole-body exposure for 200s and of human amniotic cells in vitro for 2000s at 34°C. Spatial average intensity was 1 W/cm². Cyclic AMP, cyclic GMP and histamine in mouse skin, lung and peritoneal cells, and cAMP and cGMP in human amniotic cells were assayed as sensitive indicators of membrane damage. No significant effect of ultrasound was observed. Statistical analysis indicates an 80% probability that we would have detected a difference in the means for exposed and sham exposed groups if it had been greater than one standard deviation in 9 out of 18 comparisons for mouse tissues and 7 out of 8 comparisons for human amniotic cells.     

In vitro and in vivo transport of lithium by human erythrocytes.

An in vitro system that can be used to measure both uptake and efflux of lithium by erythrocytes (RBCs) is described. Using this system, RBC lithium accumulation in vitro was compared with in vivo RBC lithium concentrations observed in 6 normal volunteers. A significant correlation was demonstrated between in vitro RBC lithium accumulation after 48-hr incubation and in vivo RBC lithium concentration at 24, 48, 72, and 96 hr following the beginning of lithium ingestion. In addition, when efflux of lithium from RBCs in vitro was studied, a significant correlation was observed between residual lithium in RBCs and in vitro RBC lithium accumulation. Finally, it has been demonstrated that storage of blood in ice for 5 hr prior to incubation with lithium results in increased RBC lithium accumulation. A potential role for this in vitro incubation system as a model for in vivo RBC lithium accumulation is suggested.     

In vivo effect of thiolutin on cell growth and macromolecular synthesis in Escherichia coli

Thiolutin reversibly inhibits growth and ribonucleic acid synthesis in Saccharomyces cerevisiae. It is now demonstrated that, at 5 mug/ml, thiolutin rapidly inhibits all incorporation of radioactive precursors into ribonucleic acid and protein in Escherichia coli, although the incorporation of deoxythymidine into deoxyribonucleic acid continues for some time. Concentrations of thiolutin of 5 mug/ml and above are bacteriostatic and do not lead to unbalanced growth, so that cell size remains constant. The antibiotic and its inhibitory effects are easily removed by washing, whereupon macromolecular synthesis and cell division resume unimpeded. These data are consistent with reversible inhibition of ribonucleic acid synthesis being the primary mode of action of thiolutin in E. coli, and suggest that thiolutin may be a useful tool for studies where such reversible inhibition is required.     

gamma-Glutamyltransferase in human and mouse breast tumours.

A series of experimental mouse tumours were assayed for their gamma-glutamyltransferase activities. Significantly raised activities were found in a transplantable spontaneous mammary carcinoma compared to normal or lactating mouse breast. A study was therefore undertaken of human breast tumours. Carcinomas showed significantly elevated enzyme levels when compared with normal tissue or histologically uninvolved tissue from a breast containing a carcinoma. Fibroadenoma and chronic mastitis also showed significantly elevated levels when compared with normal tissue and did not differ significantly from carcinoma tissue. Benign breast cyst fluid showed very high levels of enzyme activity. Binding properties of the enzyme to Con A-Sepharose suggested that while normal tissue and fibroadenomas contained only asialated enzyme, carcinomas, chronic mastitis and cyst fluid contained a substantial proportion of sialated enzyme.     

In vitro and in vivo protective effect of atriopeptin III on ischemic acute renal failure.

The effect of atriopeptin III (AP-III) on ameliorate ischemic acute renal failure was first examined in the isolated perfused kidney. Isolated rat kidneys were clamped for 1 h and reperfused for 30 min without therapy and then perfused with either 0 (control) or 100 micrograms/dl AP-III. In this system AP-III significantly improved renal plasma flow (39.6 +/- 2.4 vs. 32.2 +/- 2.1 ml/min per g; P less than 0.05) inulin clearance (182.6 +/- 49.2 vs. 24.6 +/- 6.2 microliters/min per g; P less than 0.05), urine flow (52.9 +/- 12.1 vs. 7.1 +/- 0.8 microliters/min per g, P less than 0.01), and net tubular sodium reabsorption (21.2 +/- 6.6 vs. 2.9 +/- 0.9 mumol/min per g, P less than 0.05) as compared with control. A second series of in vivo studies experiments were performed using 1 h of bilateral renal artery clamping followed by an intravenous infusion of either saline alone (control) or AP-III (0.20 microgram/kg per min) for 60 min. The results demonstrated that inulin clearance (244.4 +/- 25.1 vs. 15.8 +/- 8.2 microliters/min per 100 g; P less than 0.01), urine flow (23.1 +/- 5.9 vs. 1.1 +/- 0.5 microliters/min per 100 g; P less than 0.01), and net tubular sodium reabsorption (38.9 +/- 4.7 vs. 4.3 +/- 1.6 mumol/min per 100 g; P less than 0.01) were significantly higher in AP-III-treated rats than controls during the hour of AP-III infusion. In 1 h posttreatment study this significant protective effect of AP-III was documented to persist. In more chronic studies animals treated acutely with AP-III had lower serum creatinine concentration at 24 h (1.8 +/- 0.3 vs. 3.3 +/- 0.4 mg/dl; P less than 0.01) and 48 (1.0 +/- 0.2 vs. 2.4 +/- 4.0 mg/dl; P less than 0.01) after the 60 min of ischemia than controls. Renal adenosine triphosphate regeneration as assessed by P-31 nuclear magnetic resonance during reflow was also significantly improved in AP-III-treated animals at 1 h (3.03 +/- 0.30 vs. 1.45 +/- 0.40 mumol/g dry wt; P less than 0.05) and 2 h (3.98 +/- 0.46 vs. 1.80 +/- 0.05 mumol/g dry wt; P less than 0.01) or reflow as compared with control rats. Thus, AP-III significantly ameliorates ischemic acute renal failure both in vitro and in vivo in the rat.     

In vitro analysis of human drug glucuronidation and prediction of in vivo metabolic clearance

The glucuronidation of a number of commonly used hepatic uridine diphosphate glucuronosyltransferase drug substrates has been studied in human tissue microsomes. Prediction of in vivo hepatic drug glucuronidation from liver microsomal data yielded a consistent 10-fold under-prediction. Consideration of protein binding was observed to be pivotal when predicting in vivo glucuronidation for acid substrates. Studies using human intestinal microsomes demonstrated the majority of drugs to be extensively glucuronidated such that the intrinsic clearance (CL(int)) of ethinylestradiol (CL(int) = 1.3 microl/min/mg) was twice that obtained using human liver microsomes (CL(int) = 0.7 microl/min/mg). The potential extrahepatic in vivo glucuronidation was calculated for a range of drug substrates from human microsomal data. These results indicate the contribution of intestinal drug glucuronidation to systemic drug clearance to be much less than either hepatic or renal glucuronidation. Therefore, data obtained with intestinal microsomes may be misleading in the assessment of the contribution of this organ to systemic glucuronidation. The use of hepatocytes to assess metabolic stability for drugs predominantly metabolized by glucuronidation was also investigated. Metabolic clearances for a range of drugs obtained using fresh preparations of human hepatocytes predicted accurately hepatic clearance reported in vivo. The use of cryopreserved hepatocytes as an in vitro tool to predict in vivo metabolism was also assessed with an excellent correlation obtained for a number of extensively glucuronidated drugs (R(2) = 0.80, p < 0.001).     

In vitro and in vivo study on the antioxidant activity of dexrazoxane

Objectives

The iron chelator dexrazoxane has been shown to significantly reduce anthracycline-induced cardiac toxicity in several randomized controlled studies. Aim of the present study was to assess the in vitro and in vivo antioxidant effects of dexrazoxane.

Methods

The in vitro antioxidant activity of dexrazoxane as its total oxyradical scavenging capacity (TOSC) was assessed and compared to that of some classic antioxidants such as reduced glutathione (GSH), uric acid and trolox. The plasma antioxidant activity of 20 newly-diagnosed non-Hodgkin lymphoma (NHL) patients scheduled to receive anthracycline-containing chemotherapy (ProMECE-CytaBOM) was also evaluated. Results were expressed as TOSC units.

Results

Dexrazoxane exhibited an in vitro scavenging capacity towards hydroxyl radicals 320% higher than that of GSH (p < 0.00001), 20% higher than that of uric acid (p < 0.001), and 100% higher than that of trolox (p < 0.001). In the clinical study, ProMECE-CytaBOM infusion significantly reduced plasma TOSC in NHL patients (p = 0.0001). Dexrazoxane supplementation was able to restore plasma antioxidant activity in two hours from the end of the ProMECE-CytaBOM infusion.

Conclusions

Dexrazoxane has in vitro antioxidant capacity. In vivo, it is able to reduce the epirubicin-induced free radical production. The intrinsic antioxidant effect of this compound could explain the reduction of the anthracyclines-induced toxicity in those patients treated with dexrazoxane supplementation.     

In vitro and in vivo activities of synthetic trioxolanes against major human schistosome species

Schistosomiasis is a parasitic disease that remains of considerable public health significance in tropical and subtropical environments. Since the mainstay of schistosomiasis control is chemotherapy with a single drug, praziquantel, drug resistance is a concern. Here, we present new data on the antischistosomal properties of representative synthetic 1,2,4-trioxolanes (OZs). Exposure of adult Schistosoma mansoni for 24 h to a medium containing 20 mug/ml OZ209 reduced worm motor activity, induced tegumental alterations, and killed worms within 72 h. While exposure of S. mansoni to OZ78 had no apparent effect, addition of hemin reduced worm motor activity and caused tegumental damage. Administration of single 200-mg/kg of body weight oral doses of OZ78, OZ209, and OZ288 to mice harboring a juvenile S. mansoni infection resulted in worm burden reductions of 82.0 to 95.4%. In the adult infection model in mice, single 400-mg/kg doses of these compounds resulted in a maximum total worm burden reduction of 52.2%. High worm burden reductions (71.7 to 86.5%) were observed after administration of single 200-mg/kg doses of OZ78 and OZ288 to hamsters infected with either juvenile or adult S. mansoni. A single 200-mg/kg dose of OZ78 to hamsters infected with adult Schistosoma japonicum resulted in total and female worm burden reductions of 94.2 to 100%. Our results, along with the low toxicity, metabolic stability, and good pharmacokinetic properties of the OZs, indicate the potential for the development of novel broad-spectrum antischistosomal OZ drug candidates.     

In vivo and in vitro blocking of human lymphocyte Fc gamma-receptors by intravenous gammaglobulin

Lymphocyte subpopulations were measured in patients with idiopathic thrombocytopenic purpura before and immediately after high dose intravenous gammaglobulin (IV-IgG) therapy. A significant relative and absolute reduction in the Fc gamma-receptor bearing lymphocyte subpopulation was observed in 5 out of 7 patients tested. In vivo modulation of lymphocyte Fc gamma-receptors therefore probably occurs: an effect which may be attributable to the Fc gamma R-blocking anti-lymphocytic antibodies found in IV-IgG preparations. In vitro studies showed that IV-IgG preparations also contain antibodies with the capacity to block Fc gamma-receptors on human monocytes and polymorphs and that these antibodies can inhibit the T cell response to phytohaemagglutinin. These anti-lymphocyte antibodies may be important in the mode of action of high dose IV-IgG therapy.