Comparative effects of ftorafur and 5-fluorouracil on DNA synthesis in rat small intestine.

The effect of equimolar doses of ftorafur (100 mg/kg) and 5-fluorouracil (65 mg/kg) on the $\text{in}$$\text{vivo}$ incorporation of deoxyuridine and thymidine into the DNA of rat small intestine was studied. 5-fluorouracil produced a greater than 90% inhibition of deoxyuridine incorporation within one hour after injection. This degree of inhibition was sustained for at least 12 hours. Deoxyuridine incorporation was inhibited by 30 to 65% during the initial six hours after the injection of ftorafur. By 12 hours the rate of incorporation had returned to 66% of the control value. Neither drug inhibited thymidine incorporation into DNA. A study of the metabolic disposition of radioactively labeled ftorafur and 5-fluorouracil showed that the latter drug was more rapidly and completely converted to fluorouracil-containing nucleotides in the small intestine. The possible relationship between these findings and the reported differences in the toxicity of the two drugs is discussed.     

Study of energy characteristics of 5-fluorouracil analogs by photoionization mass-spectrometry

The fragmentation pathways of N-1-alkoxyalkyl derivatives of 5-fluorouracil and various analogues of an antitumor drug ftorafur have been examined using a mass-spectrometry technique. The ionization and appearance energies for major ions of the compounds under study have been determined on the basis of the ionization efficiency curves obtained using photoionization mass-spectrometry. Different transport forms of 5-fluorouracil have been demonstrated to be similar in the stability of their pseudoglycosidic C-N bond.     

Validation of a gas chromatography-mass spectrometry method for the determination of pg/ml levels of 17beta-estradiol and 17beta-trenbolone in bovine serum

A method for the quantitation of pg/ml levels of 17beta-estradiol and 17beta-trenbolone in bovine serum by gas chromatography/electron-capture mass spectrometry has been developed and validated. Using the area ratios of the integrated molecular-ion peaks of the analytes to their corresponding deuterated internal standards, [2,4,16,16-2H4] 17beta-estradiol (17beta-estradiol-d(4)) and [16,16-2H2] 17beta-trenbolone (17beta-trenbolone-d(2)), and non-weighted linear regression, two calibration curves per analyte; 5-50 and 50-500 pg/ml for 17beta-estradiol in sera, and 25-250 and 250-2500 pg/ml for 17beta-trenbolone in sera, respectively, were constructed. Splitless injection of 200 fg 17beta-estradiol and 1000 fg 17beta-trenbolone could be detected and quantified. Tested batches of control bovine sera did not exhibit interference for 17beta-trenbolone, and showed expected background presence of endogenous 17beta-estradiol. Intra-day residual errors did not exceed 20%, and regression correlations were greater than 0.99. Intra-day precision data was similar to inter-day precision data. Using this method, 16 samples can be processed within one working day.     

Purification of rat liver asparagine synthetase by affinity chromatography on reactive blue 2-agarose

Studies on analysis of free animo acids using a support-coated, open-tube capillary column, and electron-capture detection or selective ion monitoring have been performed on samples from biological microenvironments. For most amino acids the detection limit was found to be less than 1 pg. The preparation of the support-coated open-tube capillary column is described as well as the gas-chromatographic conditions for direct injection and temperature-programmed separation of the N-heptafluorobutyryl iso butyl ester derivatives. Electron-capture detection and selected ion monitoring are compared with respect to linearity and sensitivity and the bases for the greater sensitivity of electron-capture detection compared with flame-ionization detection using halogenated derivatives is discussed. Applications of the gas-chromatographic method for analysis of free amino acids in environments deliberately chosen very small are demonstrated.     

Biochemical bases of ftorafur-potentiating effects of perfluorodecalin, inducer of cytochrome P-450 dependent microsomal monooxygenases]

Activity of cytochrome P-450-dependent monooxygenase system is significantly lower in hepatoma H-2-73 and Lewis lung carcinoma-bearing mice as compared to that in control animals. An inhibition of the cytochrome P-450 system was observed after the injection of ftorafur. Treatment of the mice with perfluorodecalin markedly increased the antineoplastic activity of ftorafur determined by a loss of the leucocytes and of the weight hepatoma H-2-73- and Lewis lung carcinoma resistant to ftorafur alone.     

Effect of ftorafur and 5-fluorouracil on the chromosomes of human tumor cell cultures]

The effect of two antitumour drugs, ftorafur (Ft) and 5-fluorouracil (5-FU) on chromosomes of human tumour cells (strain CA-1) was studied in vitro. Since no data on the karyotype of this tumour strain had been published, the chromosome set of the model was investigated at first. Significant quantitative and structural divergence from the normal human male karyotype were observed. Steam line cells contained 47-49 chromosomes, including 9 permanent markers. No Y-chromosome was revealed. Ft and 5-FU hardly injured the chromosomes of CA-1 cells; the level of aberrant metaphases reached 94%. Chromatid deletions and gaps formed the major part of drug-induced cytogenetic abnormalities.     

Differential recovery of intestine, bone marrow, and thymus of rats with solid tumors following 5-fluorouracil administration.

Time relationships for recovery of several host organs from toxic effects of 5-fluorouracil were determined in ACI rats bearing Morris hepatoma 3924A. A single injection of 150 mg/kg body weight 5-fluorouracil (the LD10) resulted in loss of 90% of the tibial bone marrow, 60% of the intestinal mucosa, and 90% of the thymus as measured by total DNA content of the organs. Organ DNA contents following 150 mg/kg of the drug were minimal on day 3 for intestine and on day 5 for marrow and thymus. A return to pretreatment or higher levels of DNA was observed by day 4 for intestine, day 11 for tibial marrow, and day 19 for thymus. Incorporation of 3H-deoxyuridine into host organ DNA after 150 mg/kg 5-fluorouracil was inhibited 36 hrs for intestine, 3 days for thymus, and 5 days for tibial bone marrow. Inhibition of 3H-deoxyuridine incorporation into DNA was similar for 50, 100, and 150 mg/kg doses both in tumor and in host organs, but recovery of 3H-deoxyuridine incorporation and DNA content of host organs began later with the higher doses of 5-fluorouracil. Maximal incorporation of 3H-deoxyuridine into DNA was observed on day 4 for intestine, day 8 for marrow, and day 9 for thymus after treatment with 150 mg/kg 5-fluorouracil. Animal lethality following the second of two 150 mg/kg injections of 5-fluorouracil was related to the extent of recovery of intestinal mucosa and bone marrow at the time of the second injection. Survival decreased to 0% for normal rats when the interval between injections was 3-4 days, improved at 5 days and was 100% when the interval was 10-11 days.     

Determination of isosorbide-5-mononitrate in human plasma by high-resolution gas chromatography

A method for the determination of isosorbide-5-mononitrate (5-ISMN) in human plasma by capillary gas chromatography with electron-capture detection was developed and applied to clinical samples. 9-Fluorenone was used as an internal standard, ethyl acetate was employed for liquid-liquid extraction. The advantage of the extraction procedure is the possibility of a direct injection of the plasma extract, without solvent removal/reconstitution of the sample. The precision and accuracy of the method were satisfactory in the concentration range 10-1600 ng/ml. The lower limit of quantification was 10 ng/ml.     

New electron-capture gas-liquid chromatographic method for the determination of mexiletine plasma levels in man

A method for the determination of mexiletine in human plasma by gas—liquid chromatography with electron-capture detection is described. Plasma samples are extracted at pH 12 with dichloromethane after addition of the internal standard, the 2,4-methyl analogue of mexiletine. A derivative is obtained using heptafluorobutyric anhydride; according to gas chromatography—mass spectrometry it is a monoheptafluorobutyryl compound. The minimum detectable amount of mexiletine is 5 pg. Accurate determinations of human plasma levels were performed after oral or intravenous treatment.     

Rapid determination of 5-fluorouracil in plasma using capillary electrophoresis

A rapid, simple and sensitive capillary electrophoresis (CE) method used for the determination of 5-fluorouracil in rabbit plasma is described in the present paper. In this method, samples were simply pretreated by a solvent extraction procedure prior to injection. With a running buffer composed of 30 mM Tris-H(3)PO(4) (pH 7.0) and 5% isopropanol, 5-fluorouracil was easily separated from the external standard alpha-phenethylol as well as other substances existed in the plasma. A linearity of 5-fluorouracil was determined in the range from 0.17 to 42.50 microg/ml with a correlation coefficient of 0.999. A limit of quantitation (LOQ) corresponding to signal-to-noise ratio of 10 was obtained (LOQ=0.08 microg/ml). The method was successfully used for determining the 5-fluorouracil in real plasma samples from rabbits.     

Determination of delta-aminolaevulinic acid in biological fluids by gas-liquid chromatography with electron-capture detection

A derivative of delta-aminolaevulinic acid (AmLev), 2-methyl-3-acetyl-4-(3-propionic acid pentafluorobenzyl ester)pyrrole, with favourable properties for g.l.c. with electron-capture detection, was synthesized. Less than 1 pg could be detected on the column. 6-Amino-5-oxohexanoic acid formed the analogous derivative under similar conditions and was used as the internal standard in the development of a highly sensitive and specific assay for AmLev. The method has been applied to peripheral-venous and umbilical-cord plasma and to cerebrospinal fluid of normal and porphyric subjects.     

Quantitative microdetermination of DNA by two-dimensional electron capture gas chromatography of the thymine constituent

A highly sensitive and specific two-dimensional electron-capture gas chromatographic method has been developed for determining small amounts of DNA by measuring its thymine content. The method can also be used to measure RNA based on uracil content. The nucleic acids were hydrolyzed and released constituents were separated and detected as their chloromethyldimethylsilyl ethers. The minimal amount detected was 5 pg of each base. Standard curves were linear from 5 to 200 pg. This method allowed quantitative determination of 2 ng of DNA (routinely detectable quantity) after hydrolysis of biological material in formic acid, even in the presence of large amounts of RNA and/or protein. For example, this method has been shown to be successful in determination of the DNA contents of manually isolated nucleic such as from amphibian oocytes. Besides being accurate, the procedure was rapid: after maximal hydrolysis (usually about 45 min) the derivatization and gas chromatographic analysis was completed in another 15 min. The procedure described represents a direct biochemical alternative to cytophotometric estimation of nuclear contents and has the advantage of providing values for absolute DNA content per nucleus.     

Haemolymph ecdysteroid in the housefly,Musca domestica,during oögenesis and its relationship with vitellogenin levels

Ecdysteroid titre in the haemolymph of the housefly, Musca domestica, cycled during oögenesis and peaked at ～50 pg/μl during stages 5, 6 and 7. Levels of 10–20 pg/μl were found in houseflies with pre- and post-vitellogenic ovaries. Removal of the corpus allatum and corpus cardiacum complex resulted in low ecdysteroid levels (10 pg/μl). Ovariectomized flies also had lower ecdysteroid levels than the controls at 2 days (5 pg/μl) after emergence but not at 6 days (22 pg/μl). It is possible that the ecdysteroid peak that occurred during stages 5, 6 and 7 was produced by the ovaries because ovaries secreted and synthesized ecdysteroid in vitro. Endogenous haemolymph ecdysteroid levels had a linear correlation with the amount of vitellogenin that held for hormone concentrations of 5–43 pg/μl. Furthermore, the injection of 20-hydroxyecdysone at doses of 10 ng?1.0 μg/fly increased the amount of vitellogenin from 6 h to 12 h after injection; by 24 h, the vitellogenin returned to control levels. When 20-hydroxyecdysone was injected into ovariectomized flies, it was rapidly degraded and 96% was cleared from the haemolymph within 1 h.     

Elaboration of the combination of antitumor preparations bleomycetin + 5-fluorouracil + cisplatin

Clinical trials on efficacy and toxicity of combined use of bleomycetin, 5-fluorouracil and cisplatin in patients with disseminated tumor processes were conducted. Two regimens were applied. Regimen I included intravenous administration of cisplatin in a dose of 100-150 mg/m2 on day 1, intramuscular administration of bleomycetin in a dose of 10 mg on days 2-4 and intravenous jet injection of 5-fluorouracil in a dose of 400 mg/m2 on days 2-4. Regimen II consisted of intramuscular administration of bleomycetin in a dose of 10 mg on days 1-3, intravenous jet injection of 5-fluorouracil in a dose of 400 mg/m2 on the same days and intravenous administration of cisplatin in a dose of 100-150 mg/m2 on day 4. The intervals between the courses amounted to 4 weeks. Complete regression of cervical carcinoma relapsing was observed in 1 patient. In 5 patients i.e. 1 with small-cell lung cancer, 3 with squamous cell lung cancer and 1 with metastases of low-differentiated cancer from an undetected focus to supraclavicular lymph nodes the effect was partial. Long-term stabilization of the disease at the background of the treatment for 6-7 months was stated in 3 patients. On the whole the objective response was in 6 out of 22 patients or in 27 per cent. 7 of them were treated with cisplatin in a dose of 150 mg/m2. The regimens of the combined use of 5-fluorouracil, bleomycetin and cisplatin were low toxic. The therapeutic effect showed that the combination was of practical value.     

Determination of ritodrine in biological fluids of the pregnant sheep by fused-silica capillary gas chromatography using electron-capture detection

A sensitive and selective gas chromatographic assay method employing splitless injection, fused-silica capillary columns and electron-capture detection is reported for the quantitation of the tocolytic drug, ritodrine, in a variety of biological fluids obtained from the pregnant ewe and fetus. This method has improved sensitivity and selectivity over previously published assay procedures. A 25 m × 0.31 mm I.D., cross-linked 5% phenylmethylsilicone, fused-silica capillary column was employed for all analyses. Linearity of response was observed over the range 2.5–75 ng of ritodrine base per 0.05–0.5 ml of biological fluid, representing ≈ 1–75 pg at the detector. The coefficient of variation was less than 10% over the range 2.5–75 ng of added ritodrine. The minimum quantifiable amounts is ≈ 2.5 ng from a 0.5-ml biological fluid sample. Applicability of this method to biological fluids, obtained from ovine subjects, is demonstrated by the analysis of samples obtained during the course of ritodrine placental transfer studies.     

The effect of 5-fluorouracil on the mitotic cycle and DNA synthesis in the epithelium of mouse small intestine.

The examinations were performed on 42 mice of the Porton strain. The experimental animals were injected intraperitoneally with the dose of 75 mg of 5-fluorouracil per kg body weight. The first experimental group received injections of [3H]thymidine within 48 hours and the second group within 96 hours of the injection of 5-fluorouracil. Two mice from each group were killed at within 1, 2, 4, 8, 12, 24, and 48 hours of the [3H]thymidine injection. Calculations of the mitotic index and time of duration of individual phases of the mitotic cycle in epithelial cells of the small intestine were based on application of the autoradiographic method. These studies lead to the conclusion that 5-fluorouracil disturbs the course of metabolic processes in the cell, which are also related with the distribution of the genetic material. Histological examinations show that 5-fluorouracil produces profound morphological changes in the intestine, which affect both the intestinal epithelium and the connective tissue stroma. The autoradiographic tests revealed a considerable suppression of the mitotic activity of the epithelium of intestinal crypts. Moreover, it was shown that 5-fluorouracil inhibits the mitotic activity of the intestinal epithelium by diminishing the number of cells capable of entering into mitosis. Nevertheless, by 96 hours following introduction of a single dose of 5-fluorouracil normal morphological structure and mitotic activity of the intestinal wall cells are restored.     

Improvement and initial in vivo application of the radioimmunoassay of rat thyrocalcitonin.

Previously we reported a homologous radioimmunoassy for rat thyrocalcitonin (TCT) which was sensitive enough (2--3 ng/ml serum) to measure TCT in thyroid venous blood or thyroid gland extracts but could not detect TCT in peripheral blood even after provocative challenge with iv calcium. In the present study chicken antisera to rat TCT were developed which were sufficiently sensitive (120--240 pg/ml serum) to permit initial evaluation of changes in TCT in rat peripheral blood. The following results were observed: (1) Basal serum TCT in young male Holtzman rats was undetectable, being less than 120--240 pg/ml; (2) induction of marked hypercalcemia by iv calcium increased TCT to approximately 1000--3000 pg/ml within 5 min; (3) thyroid cautery increased TCT to approximately 1000 pg/ml in 5--15 min; (4) calcium gavage (12.2 mg Ca/100 g) produced modest hypercalcemia in 30--60 min and increased serum TCT to approximately 500 pg/ml; (5) injection of isoproterenol raised serum TCT detectably; (6) injection of large doses of gastrin or pentagastrin did not produce detectable increases in TCT 5 or 30 min later. The results show that suitable antisera to rat TCT can be developed in chickens and applied to the measurement, by radioimmunoassay, of elevated circulating levels of TCT in the rat.     

PLGA-5-氟尿嘧啶缓释微球治疗结直肠癌裸鼠的探讨

目的研究PLGA-5-氟尿嘧啶缓释微球瘤周给药对结直肠癌移植瘤的治疗效果。方法将60只结直肠癌荷瘤鼠随机分为6组,每组10只。A、B组瘤周注射PLGA-5-氟尿嘧啶缓释微球,5-氟尿嘧啶剂量分别为200mg/kg和100 mg/kg;C、D组瘤周注射5-氟尿嘧啶注射液,5-氟尿嘧啶剂量分别为200 mg/kg和100 mg/kg;E组瘤周注射PLGA微球,800 mg/kg;F组不给予任何治疗。于0、3、6、9、12、15d观察裸鼠生存状况、称体重、测量肿瘤大小。15d时处死动物,称瘤重,计算抑瘤率,绘制肿瘤生长曲线;取血行白细胞计数、肝肾功能检查。结果A、B组肿瘤生长曲线平缓,15 d时A、B组肿瘤体积与C、D、E、F组比较,结果差异有显著性,C、D组肿瘤体积与E、F组比较差异无显著性;A、B组抑瘤率分别为75%和62%,与C、D组比较,结果差异有显著性;A、B、C、D、E组体重在0 d及15 d与F组比较,差异无显著性,15 d时各组白细胞计数及肝肾功能检查值均在正常范围。结论PLGA-5-氟尿嘧啶缓释微球瘤周给药能有效抑制结直肠癌移植瘤的生长,且无明显的毒副作用。     

Action of ftorafur on the chromosomes of normal and tumorous cells of the Djzungarian hamster in vitro]

The chromosome-breaking effect of antitumor agent ftorafur (0,1 mg/ml) was studied on cell cultures of normal and transformed Djungarian hamster's fibroblasts. After 24 hours of exposition with the drug 79% of aberrant malignant cells was registered, while the chromosomes of normal cells remained undamaged. After ftorafur's action for 2--12 hours and the following removal of the agent the level of aberrant metaphase among normal cells rose to 11--15%. Chromatid breaks were the predominant type of drug-induced aberrations. Thse results confirm the idea that ftorafur blocks the cell cycle of normal fibroblasts and that it's necessary to wash the drug off some period before fuxation in order to reveal its chromosome-breaking effect in metaphase cells. The striking distinctions in susceptibility of normal and malignant cells to the mutagenic effect of ftorafur is partly due to the distrubances of the cell cycle caused by this drug.     

An electron-capture gas–liquid-chromatographic method for the determination of prostaglandin F2α in biological fluids

A sensitive electron-capture gas-liquid-chromatographic method for the determination of sub-nanogram quantities of prostaglandin F(2alpha) was developed. The method is based on the sub-microgram scale conversion of the prostaglandin into the electron-capturing pentafluorobenzyl ester, and analysis of the latter as the tris-trimethylsilyl ether. The lower limit of detection was 12.5pg of the ester injected ;on-column' as the silylated product. The method was successfully applied to the determination of prostaglandin F(2alpha) in monkey plasma. The specificity of the analytical procedure was increased by incorporating a thin-layer chromatographic fractionation before gas-liquid chromatography. The utility of the analytical methodology developed was demonstrated by its application to the determination of plasma concentrations of intact prostaglandin F(2alpha) in a Rhesus monkey, after subcutaneous administration of a single dose of prostaglandin F(2alpha). The electron-capture gas-liquid-chromatographic assay is compared with the radioimmunoassay and the gas-liquid-chromatographic-mass-spectrometry assay for the determination of prostaglandin F(2alpha).