19F magnetic resonance spectroscopy studies of the metabolism of 5-fluorouracil in murine RIF-1 tumors and liver

The metabolism of 5-fluorouracil (5FU) in tumors and livers of RIF-1 tumor-bearing C3H mice given i.p. injections of 5FU was serially monitored by 19F magnetic resonance spectroscopy. The levels of 5FU and fluoronucleotide detected in the tumors after a dose of 130 mg/kg (n = 13) were less than one-third of those after 260-mg/kg 5FU (n = 14). During the days after these doses, tumor size decreased by 24 +/- 3 and 52 +/- 6 SEM%, respectively. A second 130-mg/kg dose, given at day 7 after the first 130-mg/kg dose, resulted in still lower tumor fluorine levels and little change in tumor size. There was a significant correlation between the magnetic resonance spectroscopy-detected fluoronucleotide levels and the shrinkage of tumors after the 260-mg/kg dose (r = 0.44; P = 0.024). In mouse liver, the degradation of 5FU to alpha-fluoro-beta-ureidoprobionic acid and alpha-fluoro-beta-alanine after the 260-mg dose (n = 13) was slower than after a dose of 130 mg/kg (n = 14). For the respective doses, the half-life of 5FU was 59 +/- 7 versus 28 +/- 2 SEM min (P less than 0.0001). There was a negative correlation between the levels of 5FU catabolite (alpha-fluoro-beta-ureidoprobionic acid and alpha-fluoro-beta-alanine) in liver and fluoronucleotide in tumor (r = -0.80; P = 0.0020), which indicates that the degradation in liver and the activation of 5FU in tumor are competing processes.

[Experimental and clinical studies of the effect of dahuang zhechong wan on hyperlipemia]

Experimental and clinical researches were done for the purpose of that to treat the hyperlipemia with Dahuang Zhechong Wan (DHZCW). The patients of primary hyperlipemia were divided into two groups. One group was treated with DHZCW, the other with inositol nicotinate as control. DHZCW could reduce the serum total cholesterol (0.05 less than P less than 0.2), triglyceride (P less than 0.05), the blood viscosity (P less than 0.01), reductive viscosity (P less than 0.001) and fibrinogen (0.05 less than P less than 0.2). No significant change of the other item of hemorheology, HDL-c and the subfraction were observed. No significant differential effect between those two groups. The experimental hyperlipidemic model was made by feeding cholesterol and axungia on rabbits. The results showed that DHZCW could reduce the serum total cholesterol (P less than 0.05), triglyceride (P less than 0.05), beta-LP (P less than 0.01), the blood viscosity (P less than 0.05) and plasma viscosity (P less than 0.05), but no significant effect on HDL-c and its subfraction, ESR, index of erythrocytic deformation and hematocrit. DHZCW could change the viscosity of blood of hyperlipemia and reduce the total cholesterol, triglyceride and fibrinogen of the blood. It might have some beneficial effects on atherosclerosis and prevent ischemic cardiovascular and cerebrovascular diseases.

[Studies on the quantitation of trace elements in complex prescription decoctions of ochre and calcined ochre]

The present paper reports the determination of Fe, Cu, Zn, Mn and As in complex prescription decoctions of ochre and calcined ochre by atomic absorption spectroscopy. The experimental result shows that in most complex prescription decoctions the contents of Fe, Mn and As are lower in these with calcined ochre than with ochre. The contents of Zn and Cu are higher in the decoctions with calcined ochre than those with ochre.

Hypotensive effect of dehydroevodiamine from Evodiae Fructus

Dehydroevodiamine isolated from Evodiae Fructus lowered blood pressure with bradycardia in anesthetised rats. At a cumulative dose of 22.5mg/kg/30min, there was a very significant decrease in blood pressure and heart rate. There was a more important decrease in diastolic pressure than systolic pressure, implying a vasodilatory effect. The hypotensive effect of dehydroevodiamine can be abolished partly by indomethacin and more completely, polyphoretin phosphate. It is suggested that the hypotensive effect of dehydroevodiamine may be mediated through prostaglandin synthesis. A similar action mechanism in dehydroevodiamine-stimulated rat uterus contraction is also discussed.

Thermodynamics of the interaction of daunomycin with DNA

The association constant for the interaction of daunomycin with DNA was determined as a function of temperature (using [3H] daunomycin in conventional equilibrium dialysis cells) and ionic strength (using a spectrophotometric titration method). The association constant varied between 3.1 X 10(-6) M(-1) (4 degrees C) and 3.9 X 10(5) M(-1) (65 degrees C). The free energy change was -8.2 to -8.8 kcal/mol, the enthalpy change -5.3 kcal/mol and the entropy change +10 to +11 eu, all values being consistent with that expected of an intercalation process. The apparent number of intercalation sites detected (0.15 to 0.16 per nucleotide) was independent of temperature. The large positive entropy change accompanying the interaction appears to be due to extensive release of water from the DNA and daunomycin. The apparent number of binding sites increased dramatically with decrease of ionic strength, although the apparent association constant remained largely unaffected by ionic strength.

Mode of action of the bioreductive alkylating agent, 2,3-bis(chloromethyl)-1,4-naphthoquinone

The bioreductive alkylating agent, 2,3-bis(chloromethyl)-1,4-napthoquinone (CMNQ), has been shown to inhibit the growth of Sarcoma 180 ascites cells in vivo. Evidence for the reductive activation of this agent via the mitochondrial respiratory chain was provided by CMNQ-induced oxidation of reduced nicotinamide adenine dinucleotide; the interaction was shown to be on the substrate side of the site of rotenone inhibition. Consistent with the concept that reduction of CMNQ to a hydroquinone results in the generation of an alkylating species (i.e., a quinone methide) was the finding that radioactivity from [14C]CMNQ present in Sarcoma 180 ascites cells was associated with DNA, RNA, and protein for a period of up to 72 hr after exposure to tumor-bearing animals to this agent. Inhibition of the incorporation of [3H]thymidine, [3H]uridine, and [14C]leucine into DNA, RNA, and protein, respectively, of Sarcoma 180 ascites cells was produced by this agent, with DNA biosynthesis being the most susceptible. The inhibitory effect of CMNQ on the formation of DNA was, at least in part, the result of a prevention of the conversion of thymidine to its nucleotide forms. This action was due to (a) a drug-induced decrease in intracellular levels of adenosine 5'-triphosphate, presumably resulting from uncoupling of oxidative phosphorylation by CMNQ; and (b) a partial loss of thymidine kinase activity in Sarcoma 180 cells, which did not appear to be due to direct inhibition of the enzyme by the drug. Although the primary event produced by CMNQ at the mitochondrial level appeared to be release of respiratory control, other effects of mitochondrial metabolism occurred. These included inhibition of reduced nicotinamide adenine dinucleotide and succinoxidase activities, as previously demonstrated, and mitochondrial swelling, which suggested interaction of CMNQ with the inner mitochondrial membrane. These findings indicate a variety of biochemical lesions are associated with the antineoplastic activity of CMNQ and demonstrate a relationship between the effects of this drug on mitochondrial respiratory control and DNA biosynthesis.