Structures of Angular Pyranocoumarins of Bai-Hua Qian-Hu, the Root of Peucedanum praeruptorum1

Three new angular-type dihydropyranocoumarins, peucedanocoumarin I ( 1), peucedanocou-marin II ( 2), peucedanocoumarin III ( 3), and a known coumarin having the same skeleton, pteryxin ( 4), were isolated from the crude drug "Bai-Hua Qian-Hu" of the Q-II type series, which is the root of PEUCEDANUM PRAERUPTORUM Dunn. (Umbelliferae). The chemical structures of 1, 2, and 3 have been established by physicochemical methods to be 3' ( S)-2-methylbutyryloxy-4'-( R)-acetoxy-3',4'-dihydroseselin, 3'( S)-acetoxy-4'( R)-angeloyloxy-3',4'-dihydroseselin, and 3'( S)-acetoxy-4'( R)-tigloyloxy-3',4'-dihydroseselin, respectively.     

Effects of MEK on kinetics ofn-hexane metabolites in serum

The neurotoxicity ofn-hexane is thought to be caused ultimately by 2,5-hexanedione (2,5-HD), one of then-hexane metabolites. The potentiation ofn-hexane neurotoxicity by co-exposure with MEK, therefore, is suspected to be related to kinetics of 2,5-HD in blood. To clarify the kinetics ofn-hexane metabolites in the mixed exposure ofn-hexane and MEK, rats were exposed to 2000 ppmn-hexane or a mixture of 2000 ppmn-hexane and 2000 ppm MEK, and the time courses of serumn-hexane metabolites were determined. 2,5-HD in serum increased until 2 h after the end of exposure, when serum 2,5-HD concentration reached a peak of 16.35 g/ml in then-hexane-alone group. In contrast, 2,5-HD in the mixed exposure group increased much more slowly during and after exposure than in then-hexane-alone group. It reached a peak of 2.12 g/ml at 8 h after the end of exposure. Serum MBK, a precursor of 2,5-HD in the co-exposure group, was about half in then-hexane-alone group during exposure. However, MBK decreased more slowly in the co-exposure group than in then-hexane-alone group after the end of the exposure. The results suggest that co-exposed MEK might inhibit oxidation ofn-hexane and decrease clearance ofn-hexane metabolites. Co-exposed MEK did not increase serum 2,5-HD, which was considered a main neurotoxic metabolite. Therefore the enhancement of neurotoxicity could not be attributed to increased serum 2,5-HD in the co-exposed group. The mechanism of enhancement of neurotoxicity ofn-hexane by MEK should be studied further.     

Tumor cell adhesion to frozen lymph node sections — a correlate of lymphatic metastasis in breast carcinoma models of human and rat origin

Summary The role of tumor cell adhesion in lymphatic metastasis of breast cancer was investigatedin vitro using a rat mammary carcinoma model of four cell lines with different metastatic phenotypes, two human breast cancer cell lines, and cryostast sections of normal rat or human lymph nodes, respectively. A positive correlation was found between the adhesion levels obtained with three metastatic rat mammary cell lines (TMT-081 > MT-100M & TMT-50) and a non-metastatic line MT-W9B, the latter being 3–4 fold less adhesive to the lymph node sections than the metastatic tumors. This selective adhesion was specific, as it was not found with cryostat sections of rat liver and brain. Enzyme assays indicated that cell surface glycoproteins bearing terminal -galactoside residues were involved in the adhesion of the rat tumors.Adhesion of the human breast carcinoma cells Hs578T to sections of human lymph nodes was significantly higher than that of the normal breast epithelial cell line Hs578Bst, and comparable to adhesion of a second breast carcinoma line, MCF-7. Moreover, Hs578T cells isolated from regional lymph nodes of tumor-bearing nude mice were significantly more adhesive to human lymph node sections than the parental line.Adhesion of both human and rat tumors could be partially blocked by the addition of the synthetic peptide GRGDSPK and by antibodies directed to the 1 chain of integrin, suggesting that an integrin receptor may played a role in the adhesion. The results suggest that tumor cell adhesion to cryostat sections of lymph nodes is a correlate of the malignant phenotype in mammary tumors of diverse origins, and could be used to delineate the adhesion factors mediating lymphatic metastasis.     

Pharmacokinetic and Pharmacological Profiles of Free and Liposomal Recombinant Human Erythropoietin After Intravenous and Subcutaneous Administrations in Rats

Purpose. Recombinant human erythropoietin (Epo) is used frequently through intravenous (i.v.) and subcutaneous (s.c.) administration for the clinical treatment of the last stage of renal anemia. We encapsulated Epo in liposomes to develop an alternative administration route. The purpose of our study was to evaluate the pharmacokinetics and the pharmacological effects of liposomal Epo in comparison with the Epo after i.v. and s.c. administration to rats. Methods. Epo was encapsulated in liposomes composed of dipalmitoylphosphatidylcholine (DPPC) and soybean-derived sterol mixture (SS) prepared by the reversed-phase evaporation vesicle method. After filtration through a 0.1 m polycarbonate membrane, liposomes were gel filtered (Epo/liposomes). Results. Epo/liposomes showed higher pharmacological activity than Epo/liposomes before gel filtration after i.v. administration to rats. Non-encapsulated Epo lost its activity, whereas encapsulated Epo in liposomes retained it. The pharmacological effects of Epo/liposomes were greater than those of Epo after i.v. administration. Epo/liposomes afforded 3–9 times higher AUC, lower clearance and lower steady-state volume of distribution than Epo after both i.v. and s.c. administrations. Epo/liposomes had an improved pharmacokinetic profile compared with Epo. S.c. administration of Epo/liposomes at 7 h may penetrate primarily (40% of dose) through the blood as a liposome and partly (7% of dose) in lymph. Conclusions. Epo/liposomes may reduce the frequency of injections required for a certain reticulocyte effect in comparison to Epo. The lower clearance of Epo/liposomes may increase the plasma concentrations of Epo, which increases the efficacy.     

Cytotoxicity of a novel indoloquinone eo9 in hypoxic non-small-cell lung-cancer cell-lines

3-Hydroxymethyl-5-aziridinyl-1-methyl-[1H-indole-4,7-dione]-prop-beta-en -alpha-ol (EO9) is a bioreductive anticancer agent active for non-small cell lung cancer (NSCLC) and structurally related to mitomycin C (MMC). DT-diaphorase (DTD) is regarded as a two electron reductase that plays an important role in the biotransformation of MMC to antitumor metabolites. To evaluate the role of DTD as a bioactivator of EO9 in NSCLC cell lines under oxic and hypoxic conditions, we examined the inhibitory effect of dicumarol which was regarded as a selective inhibitor of DTD on the sensitivity to EO9 in vitro. In this study, we used an MMC-resistant NSCLC cell line (PC-9/MC4) which was established from a PC-9 cell line as a parent cell line by continuous exposure to MMC in our laboratory. We reported previously that the subline PC-9/MC4 was 6.7-fold more resistant to MMC than PC-9 with decreased DTD activity. The IC50 value of PC-9 against EO9 was significantly increased by co-incubation with dicumarol under oxic conditions. EO9 was more cytotoxic against PC-9/MC4 than against PC-9 cells and the enhancement was impaired by tempol under hypoxic conditions. These findings suggest a suppressive role of DTD against one-electron reduction pathway in the bioactivation of EO9 under hypoxic conditions and EO9 may be more active against oxygen-deficient solid tumors especially in MMC-resistant NSCLC cells with low levels of DTD activity.     

Serum leptin level among non-obese students: relationship to body fat, blood pressure, serum lipids, physical activity, and eating habits]

Leptin, a product of the ob gene, is thought to play a key role in the regulation of adiposity. However, it is unclear in humans as to whether or not leptin influences the blood pressure, serum lipids, physical activity level, or eating behavior in relation to obesity. Recent reports have indicated both gender-based differences in the leptin levels and a correlation of the percentage of body fat with leptin levels has been observed among obese subjects. As far as we know, these relationships among non-obese young adults have yet to be studied. Therefore, the serum leptin concentrations among 107 non-obese students (72 males and 35 females) were measured by a radioimmunoassay(RIA). Fasting leptin levels ranging between 1.2 and 23.4 ng/mL were observed in all subjects, and the levels among females were 2.6 times higher than in males (7.64 vs 2.95 ng/mL; p < 0.001). A close correlation was observed regarding the log-transformed leptin levels with the percentage of body fat as determined by the bioelectrical impedance analysis method(r = 0.734, p < 0.001 in males and r = 0.579, p < 0.001 in females). In conclusion, these data thus suggest the serum leptin levels among non-obese students show significant gender-based differences while, in addition, the leptin levels also correlate positively with the percentage of body fat. However, it remains unclear as to whether or not the leptin levels are independently related to the blood pressure, serum lipids, physical activity level (sports activity and leisure-time activity), and eating behavior (eating breakfast, mid-day snacking and nighttime snacking).     

Percutaneous microwave hepatic tumor coagulation with segmental hepatic blood flow occlusion in seven patients

OBJECTIVE: We assess the usefulness of microwave hepatic tumor coagulation therapy with balloon occlusion of segmental hepatic blood flow for eight recurrent metastatic hepatic tumors in seven patients. CONCLUSION: Limited early experience with microwave hepatic tumor coagulation therapy and segmental hepatic blood flow occlusion has been positive, suggesting that further clinical evaluation is warranted.     

Role of reactive oxygen in phospholipase A2 activation by ischemia/reperfusion of the rat kidney

Purpose. To investigate the role of phospholipase A₂ (PLA₂) in reperfusion injury of the kidney in an in vivo animal model, renal mitochondrial PLA₂ activity was measured under three different conditions. Methods. Male Wistar rats (n = 72) anesthetized with pentobarbital underwent renal ischemia surgically for 45 min and were reperfused for the indicated time (renal ischemia/reperfusion). Treatments included reperfusion for various predetermined periods (phase 1), exposure to hyperbaric oxygen (phase 2), and administration of reactive oxygen species (ROS) scavenger (phase 3). Thereafter, each kidney was harvested, and mitochondrial PLA₂ activity was measured by a radioisotope technique. Results. Ischemia/reperfusion resulted in time-related PLA₂ activation in the renal mitochondria up to 48 h of reperfusion after renal ischemia. Renal mitochondrial PLA₂ activity was further augmented by hyperbaric oxygen exposure prior to reperfusion, whereas administration of the ROS scavengers suppressed mitochondrial PLA₂ activity. Conclusion. These data suggest that ROS may play an important role in the in vivo activation of PLA₂ associated with renal ischemia/reperfusion. Received for publication on July 6, 1998; accepted on November 30, 1998     

Effects of sciatic neurectomy on the femur in growing rats: Application of peripheral quantitative computed tomography and Fourier transform infrared spectroscopy

The effects of unilateral sciatic neurectomy (USN) on the development of the femur were studied in 15 growing Wistar-derived rats (age, 5 weeks). The rats were divided into four groups: USN-operated group (right femur), USN-nonoperated group (left femur), sham-operated group (right femur), and sham-nonoperated group (left femur). Bone mineral density (BMD), bone mineral content (BMC), bone area, periosteal circumference, and endosteal circumference were measured by peripheral quantitative computed tomography (pQCT) and the mineral/matrix ratio was evaluated by Fourier transform infrared spectroscopy (FTIR). The USN-operated group showed a significant decrease in cortical BMC, bone area, and periosteal circumference compared with the other groups (P < 0.05). The cortical BMD did not vary significantly between the groups. In the cancellous bone, the USN-operated group showed a significant decrease in BMD and BMC at the metaphysis compared with the other groups (P < 0.05). The mineral/matrix ratio of the cortical bone did not differ significantly between the USN-operated and USN-nonoperated groups. These results suggest that in cortical bone, USN inhibits periosteal bone formation but has no significant effect on the mineral/matrix ratio of cortical bone in femurs. In cancellous bone, USN induces bone loss at the metaphysis. Received: Nov. 19, 1998 / Accepted: Feb. 12, 1999