Liposomes have been artificially made into membranous vesicles composed essentially of naturally occurring phospholipids and have been found to serve as a carrier of drugs and an immunological adjuvant. After being intravenously injected, they are quickly removed from the blood circulation and trapped by Kupffer cells of the liver and macrophages of spleen. However, the changes liposomes exert in these cells with which liposomes interact remain unresolved. To clarify this point is very important to assure the safe use of liposomes as drug carriers. Macrophages have many unique functions, and nitric oxide (NO) produced by NO synthase (NOS) which is induced in response to some cytokines and bacterial products such as lipopolysaccharide (LPS) is responsible for the bactericidal, tumoricidal and immune regulatory activities. On the other hand, overexpressed NO is implicated in the development of atherosclerosis, DNA injury, and hypotension associated with septic shock. This article focuses on the effects of liposomes on NO production from LPS-stimulated mice peritoneal macrophages in vitro; we found that liposomes composed of phosphatidylserine inhibit NO production. We also discuss the mechanism of the inhibitory activity of liposomes.
The effect of artemisinin on membrane fluidity of erythrocytes was investigated using spin labeling compounds, doxyl stearic acids. The membrane fluidity of erythrocytes from the in vitro culture and malaria patients was determined. In vitro, the erythrocytes in parasite culture showed an increase in membrane fluidity which was associated with the parasite counts and stage of parasites. Artemisinin caused reduction in membrane fluidity and the effect was more pronounced in the erythrocytes infected with schizont stage-parasites. In vivo, the elevation of plasma TBARs (thiobarbituric acid reactive substances) and reduction of membrane fluidity were evident in Plasmodium falciparum-infected patients, particularly in severe cases. The levels of plasma TBRs were related to the severity of the disease. Treatment with artemisinin alone showed no effect on plasma TBARs, and did not alter the membrane fluidity. Desferrioxamine, however, reduced oxidative damage during the infection without compromising the therapeutic effect of artemisinin. These findings suggested that the infected erythrocytes were prone to the effect of artemisinin. Addition of a chelator such as desferrioxamine is beneficial and can improve the treatment of severe malaria.
The specificity of the nucleotide sequence of DNA strand cleavage sites produced by dihydropyrazines, a new type of DNA strand-cleaving agent, was studied. Biotin-5'-end-labeled PCR-amplified DNA restriction fragments of different defined nucleotide sequences were prepared from plasmid pBR322, and reacted with dihydropyrazines in the presence of Cu2+. After being heated with aqueous piperidine, the DNA products were analyzed on polyacrylamide gels. The most preferentially cleaved sites induced by dihydropyrazines were at purine/pyrimidine-guanine (5'→3') sequences. The purine/pyrimidine-adenine, pyrimidine-pyrimidine and purine-pyrimidine (5'→3') sequences were more resistant to attack by these dihydropyrazines. The side chains of the dihydropyrazine skeleton greatly affected the DNA strand-cleaving activity, and also, to some extent, the nucleotide sequence-specificity in the DNA strand-cleavage.
The immunocytochemical localization of β-citryl-L-glutamate (β-CG) in primary neuronal cells and in the differentiation of P19 cells was examined. 1 : Cells with the morphological features of neurons in the primary culture were specifically stained with the anti-β-CG antibody both in neurites and in the cell body. 2 : The neuronal cells differentiated from P19 cells were distinctly stained with the anti-β-CG antibody both in neurites and in the cell body, while the non-neuronal cells were not. 3 : The concentration of β-CG was low in the P19 cells, but increased significantly with the differentiation of P19 cells into neurons. It was shown that β-CG was localized exclusively in neurons. These findings suggest that β-CG plays functional roles in the differentiation and growth of neuron.
The effects of docosapentaenoic acid (DPA) on platelet aggregation and arachidonic acid metabolism were studied in comparison to those of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Collagen- or arachidonic acid-stimulated platelet aggregation was inhibited dose-dependently by n-3 fatty acids, among which DPA was the most potent inhibitor. These fatty acids inhibited U46619-induced aggregation but to almost the same extent. No effect of the acids on thrombin-induced aggregation was observed. Furthermore, these fatty acids suppressed thromboxane A2 formation by platelets which were exposed to collagen or thrombin, or by platelets to which arachidonic acid was added. In these experiments also, DPA was the most potent inhibitor, whereas DHA was the most effective inhibitor of cyclooxygenase-1 activity. DPA enhanced formation of 12-hydroxyeicosatetraenoic acid in response to collagen or from arachidonic acid by intact platelets, while the other two acids had less of an effect. These results suggest that DPA possesses potent activity for interfering with the cyclooxygenase pathway and accelerating the lipoxygenase pathway, thus inhibiting platelet aggregation most effectively.
The effect of fractions from a water extract of Polyporus on bladder tumor promotion was examined using 5% sodium saccharin (SS) in a short-term test with concanavalin A (Con A) in Wistar rats. Rats were given N-butyl-N-(4-hydroxybutyl) nitrosamine (BHBN) in drinking water for one week, and then promoter alone or test samples (given orally) plus promoter was administered for 3 weeks. Treatment with the BuOH fraction isolated from the water extract showed a strong inhibitory effect against the promoter. It was found that the inhibitory effect of the BuOH fraction is due to the effect of ergosterol contained in the fraction. Treatment with ergosterol showed a strong inhibitory effect against 5% SS, 0.01% BHBN, 3% DL-tryptophan (Trp) or 2% butylated hydroxyanisole (BHA); ID50 was 1.4μg/kg/d, 2.9μg/kg/d, 11.6μg/kg/d, and 11.7μg/kg/d against SS, BHBN, Trp and BHA, respectivery. We also examined the effect of steroids and related compounds. Squalene and vitamin D2 showed strong inhibitory effect against 5% SS-induced bladder tumor promotion. These results strongly suggest that ergosterol could provide significant protection against the promotion of bladder tumor induced by many types of promoters in the environment.
The β-adrenergic system is very important in cardiovascular medicine. Thyroid hormone (T3) affects β-adrenergic receptors. In cell culture, isoproterenol, a β-adrenergic agonist, has been shown to upregulate thyroid hormone receptor (TR) mRNA, thus indicating a bi-directional regulation. The aim of this study was to evaluate if β-adrenoreceptor blockade may affect subtype TR mRNA expression in vivo. Propranolol or vehicle was delivered by implanting an Alzet osmotic pump subcutaneously in mice for 14d. The concentration of TRα1, α2, β1 and β2 subtype mRNA concentrations were quantified by reverse transcription-polymerase chain reaction and ELISA.Propranolol downregulated the levels of TRα1 by 44% (p<0.0005) and β1 mRNA by 39% (p<0.0005) in mouse heart, in comparison to the control, while no difference in the TRα2 or β2 mRNA levels occurred. The heart rate was reduced by 10% (p<0.05) in the propranolol group, whereas no reduction was detected in the control group. In mouse treated with propranolol serum, T3 levels were 21% lower, (p<0.05) while serum T4 levels were 23% higher (p<0.05) in comparison to the control.This is the first study suggesting that a β-adrenoreceptor blockade subtype selectively regulates TR mRNA subtypes, thus giving us further knowledge about the interaction between the β-adrenergic system and the thyroid hormone sytem.
Two iridoids, oleuropeoside and ligustroside, and two triterpenoid compounds, oleanolic acid and ursolic acid, have been isolated from the leaves of Phillyrea latifolia L. (Oleaceae). These compounds were tested for interactions with the cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) pathways of arachidonate metabolism in calcium ionophore-stimulated mouse peritoneal macrophages and human platelets, and for their effect on cell viability. Structure-activity relationships obtained for in vitro screening results were discussed. These compounds are capable of exerting inhibitory actions on enzymes of the arachidonate cascade. All compounds assayed showed a significant effect on prostaglandin E2 (PGE2)-release, with inhibition percentages similar to the reference drug indomethacin (IC50=0.95μM). The IC50 values of the active compounds are : oleuropeoside 47μM, ligustroside 48.53μM, oleanolic acid 23.51μM and ursolic acid 60.91μM. In the leukotriene C4 (LTC4)-assay, only oleanolic acid showed a significant effect (IC50=16.79μM). We also investigated the action of compounds on thromboxane B2 (TXB2)-release induced by calcium ionophore in human platelets. Of all the tested compounds, only ligustroside (IC50=122.63μM) and ursolic acid (IC50=50.21μM) showed a significant effect, although with less potency than the reference drug ibuprofen (IC50=1.27μM). Thus, our compounds possess an array of potentially beneficial anti-inflammatory properties which may, alongside other constituents, contribute to the claimed therapeutic properties of the plant from which they are derived.
In the present work we studied the anticonvulsive effects of the essential oils (EOs) from three chemotypes of Lippia alba (Mill.) N.E.Brown (Verbenaceae). Animals (female Swiss mice, 25 g) were treated with the EO and, 30 or 60 min after intraperitoneal (i.p.) or oral (p.o.) administration, respectively, injected with pentylenetetrazole (80 mg/kg, i.p.) and observed for 30 min. The results showed that EO I (200 and 400 mg/kg), EO II (100, 200 and 400 mg/kg), and EO III (400 mg/kg), i.p., produced an increased latency time for the first convulsion as related to controls. Death latency was greater in the groups receiving EO I (50 and 100 mg/kg), EO II (100 and 200 mg/kg), and EO III (200 mg/kg), i.p. Orally, while no effect was demonstrated with EOs at doses of 200 of 400 mg/kg, significant increases in the latency of convulsion and latency of death were observed with EO I at the highest dose (800 mg/kg). Similarly, EO III at this dose was also effective as far as latency of convulsion is concerned. Animals treated with citral (100 mg/kg, i.p.), β-myrcene or limonene (200 mg/kg, i.p.), EOs chemical constituents, presented significant increases in the latency of convulsion and percentage of survival as compared to controls. After oral administration these effects were observed only with a higher dose (400 mg/kg). The association of EOs with diazepam significantly potentiated their effects, suggesting a similar mechanism of action and indicating that citral, β-myrcene, and limonene are probably the EOs active compounds.
We evaluated the association between aggravation of pancreatitis and multiple factors enhancing pancreatic exocrine secretion using a rat model of pancreatic bile duct ligation (PBDL)-induced pancreatitis. Under fasting and non-fasting conditions, a PBDL group, a second group treated by hepatic bile duct ligation (BDL) and a third group treated by pancreatic duct ligation (PDL) were compared in terms of serum amylase (S-amylase) activity. The S-amylase activity in the PBDL group was higher than in the sham group. In the PDL group, the increase in S-amylase activity was lower than in the PBDL group. In the BDL group, no increase in S-amylase activity was observed. Diversion of pancreatic and/or bile juice in these groups resulted in no increase of S-amylase activity. Truncal vagotomy or injection of an anticholinergic drug or a cholecystokinin (CCK)1-receptor antagonist inhibited pancreatic exocrine secretion and S-amylase activity in the non-fasting PBDL group but not in the fasting PBDL group. These results suggest that retention of pancreatic juice in the pancreatic duct is necessary for the increase of S-amylase activity, and that dietary stimulation and impaired duodenal inflow of bile and pancreatic juice commonly enhance pancreatic exocrine secretion, acting synergistically as aggravating factors in pancreatitis. CCK and the vagus nerve system appears to be involved in enhancing pancreatic exocrine secretion with diet stimulation as an aggravating factor.
The aim of this work is to investigate the therapeutic efficacy of VP-343 ((N-[4-[[2S, 3aR)-2-hydroxy-2, 3, 3a, 4-tetrahydropyrrolo[1, 2-a]qunoxalin-5(1H)-yl]phenyl]-4'-methyl[1, 1'-biphenyl]-2-carboxamide), a selective vasopressin V2 receptor antagonist, using the experimental SIADH (syndrome of inappropriate secretion of antidiuretic hormone) rat model. In the model, which was accomplished by administering continuously 1-desamino-8-D-arginine vasopressin (DDAVP), serum sodium levels (SNa) and serum osmolarity levels (SOsm) significantly and remarkably decreased, which was accompanied with hyper-osmolarity of urine and oliguria. VP-343 increased rapidly and dose-dependently SNa and SOsm. VP-343 exhibited marked diuretic action and decreased urine osmolarity dose-dependently. In the SIADH rat model, all serum levels of chloride, calcium, creatinine, total cholesterol, and uric acid decreased when compared with normal levels. VP-343 increased all serum levels or chloride, calcium, and total cholesterol.These results indicate that VP-343 has efficacy to normalize the abnormalities in DDAVP-induced SIADH.
Hepatoprotective effect of MeOH, MeOH-H2O (1 : 1) and H2O extracts of Combretum quadrangulare seeds were examined on D-galactosamine (D-GalN)/tumor necrosis factor-α(TNF-α)-induced cell death in primary cultured mouse hepatocytes. The MeOH extract showed the strongest inhibitory effect on D-GalN/TNF-α-induced cell death (IC50, 56.4μg/ml). Moreover, the MeOH extract also significantly lowered the serum glutamic pyruvic transaminase (sGPT) level on D-GalN/lipopolysaccharide (LPS)-induced liver injury in mice. Bioguided separation of the MeOH extract led to the isolation of 38 compounds of various classes including triterpene glucosides, lignans and catechin derivatives. Among the isolated triterpene glucosides, lupane-type (1-3; IC50, 63.1, 59.8 and 76.2μM, respectively) and ursane-type (11, mixture of 12 and 14; IC50, 30.2 and 34.6μM, respectively) compounds exhibited strong hepatoprotective activity. 1-O-Galloyl-6-O-(4-hydroxy-3, 5-dimethoxy)benzoyl-β-D-glucose (26; IC50, 7.2μM), methyl gallate (28; IC50, 19.9μM), and (-)-epicatechin (31; IC50, 71.2μM) also had a potent hepatoprotective effect on D-GalN/TNF-α-induced cell death in primary cultured mouse hepatocytes.
The pharmacokinetics characteristics of propranolol (PPL) in horses was studied by administering the drug intravenously or orally to the animals. The predominant primary pathway was ring oxidation, and 4-hydroxypropranolol glucuronide (4-OHPG) was the major metabolite in both plasma and urine. Side-chain glucuronidation and oxidation were not significant. A two-compartment model was employed for PPL followed by a one-compartment model for 4-OHPG. After oral administration, one-step absorption and two-step first pass metabolism were employed. The fraction absorbed of PPL was approximately 70% after oral administration, and the bioavailability varied among individual horses from 1 to 79% depending on the first pass metabolism. The biologic half-life (T1/2) of PPL obeys the allometric equation in some animal species including rats and horses, except for human. T1/2 of PPL in horses was approximately 2 h.
We attempted to prepare a new griseofulvin formulation for topical application using N-methyl-2-pyrrolidone (NMP). Griseofulvin dissolves poorly in both water and oil, but dissolves in NMP to a concentration of about 100 mg/ml. A soybean oil-water emulsion with soybean lecithin and NMP as emulsifier and co-solvent, respectively, was prepared using a Microfluidizer, a high-pressure homogenizer. The size of the droplets in emulsion was about 200 nm, and the emulsion was stable for over 3 months. The skin permeation of griseofulvin through Yucatan micropig skin was studied in vitro using vertical type cells under donor phase open conditions. The permeation of griseofulvin from the NMP-water mixture (0-40%) into the skin tended to increase with increasing NMP concentration, although this finding was not statistically significant. Permeation from emulsion (oil phase, 20%; NMP 10-40%) was significantly higher than that from the water-NMP mixture. Permeation from the oil-NMP mixture was highest among the formulations investigated, and permeation from emulsion under donor phase closed conditions was significantly lower than that under open conditions. We believe that the evaporation of water from the emulsion after application to the skin was an important factor in skin permeation enhancement. When the emulsion containing 3% l-menthol was applied, a sufficient skin concentration (47μg/cm3 in dermis) was obtained.
The main purpose of this study was to estimate the net percutaneous absorption of physiologically active peptides in vitro. The degradation of two peptides, Leu-enkephalin (Enk) and Tyr-Pro-Leu-Gly amide (TPLG), during skin penetration and on the dermal side following penetration, and the prevention of degradation by some protease inhibitors, were investigated using rat skin in vitro. In addition, these permeation and degradation data were analyzed using a kinetic model. These peptides were rapidly degraded in the receptor fluid of a Franz diffusion cell (rate constant : 0.977 h-1 for Enk and 0.250 h-1 for TPLG). The addition of phenylmethylsulfonyl fluoride (PMSF) and phenanthroline and the pretreatment of skin with these inhibitors prevented almost completely any degradation in the receptor fluid and skin, respectively. The pretreatment of skin with PMSF and phenanthroline had no effect on the penetration of dextran (1000 Da). The degradation rate constant during skin penetration, calculated from the difference in the penetration rate constants via pretreated and untreated skins, was also high (0.037 h-1 for Enk and 0.050 h-1 for TPLG). A kinetic model including an input rate (zero-order), the permeation rate across the viable skin (first-order) and the degradation rate in skin (first-order) was sufficient to describe the apparent steady-state flux of the peptides through skin. We have, thus, established a method for measuring the true flux of peptides across skin in vitro and a kinetic model which simply describes the skin penetration of peptides.
We previously developed an in vivo pharmacokinetic model that accounts for the corneal diffusion in albino rabbits and predicts the concentration of deta-blockers in the anterior segments. The purpose of this study is to pharmacokinetically predict the ocular absorption and characterize the systemic absorption of instilled drug with ophthalmic viscous vehicle to assist in its design and evaluation. Tilisolol and carboxymethylcellulose sodium salt (CMC) were used as the model ophthalmic drug and viscous polymer, respectively. After instillation of tilisolol with CMC vehicle in rabbits, the disposition of the drug in tear fluid, aqueous humor, and plasma were determined by HPLC. The ocular and systemic absorption were analyzed by a mathematical model including a diffusion process and a two-compartment model with first-order absorption, respectively. CMC vehicle increased the area under the concentration-time curve (AUC) of tilisolol in the tear fluid and aqueous humor and slightly reduced the AUC in plasma. The concentrations of tilisolol in the aqueous humor after instillation with CMC vehicle were accurately predicted from the tear concentrations by using the in vivo ocular pharmacokinetic model. CMC vehicle improved the ocular delivery of tilisolol.
The in vitro permeation of three diclofenac salts-diclofenac sodium (DFS), diclofenac potassium (DFP) and diclofenac diethylammonium (DFD)-across skin by both passive and iontophoretic transport were investigated. Various skin types were used as the barriers to elucidate the mechanism controlling transdermal delivery of diclofenac salts. The importance of the intercellular (paracellular) route for both DFS and DFP in passive permeation was elucidated. The transfollicular route constitutes an important permeation pathway for DFS but not for DFP. The route and mechanism for transdermal iontophoresis of DFD across the skin was somewhat different to that of the other salts. Hair follicles may be a more important pathway for DFD than for DFS and DFP under iontophoresis, while the intercellular lipid pathway showed the opposite result. Combination of iontophoresis and a penetration enhancer, cardamom oil, did not show a synergistic effect on diclofenac salt permeation. The results of this investigation suggest that the transdermal mechanism and the route of diclofenac salt uptake via passive and iontophoretic transport can be affected by their counterions.
The relationship between the serum concentration and the pharmacological effect of disopyramide was investigated quantitatively to estimate the extent of its oral bioavailability (EBAp.o.) and to evaluate the drug interaction with miconazole, a CYP3A4 inhibitor. An integrated pharmacokinetic-pharmacodynamic (PK-PD) model was used to describe the relationship between the serum concentrations and changes in QT interval (pharmacological data) of disopyramide after intra-vascular infusion for 15 min (i.v. short-term infusion) to rats. A two-compartment model was applied to the pharmacokinetics of disopyramide. The pharmacological data after short-term infusion were well explained using a PK-PD link model. To validate the present PK-PD model, disopyramide was administered intra-vascularly in separate experiments, and the doses were predicted only from the pharmacological data. The model predicted doses were identical to the actual doses, regardless of the dosing rates. This result indicates that the PK-PD model used in the present study is appropriate, and that the relationship between the serum concentrations and changes in QT intervals is independent of the dosing (input) rate. When miconazole was co-administered orally 1 h before disopyramide infusion, the serum disopyramide concentrations were significantly higher than that following disopyramide alone. The raised serum concentrations under miconazole co-administration were well explained by nonlinear elimination clearance. The pharmacological effects of disopyramide under miconazole co-administration, were also greater than those following disopyramide alone. The results of the PK-PD analysis indicated that the enhanced pharmacological response under miconazole co-administration was simply caused by a pharmacokinetic change. The EBAp.o. values estimated from the pharmacological effects predicted the observed values reasonably well. In conclusion, we demonstrated following : (1) the pharmacological effect after intra-vascular administration of disopyramide is related quantitatively to the serum concentrations using a PK-PD model; (2) miconazole affects only the elimination clearance of disopyramide to enhance the pharmacological effect; (3) the EBA of disopyramide can estimated reasonably only well from the pharmacological data using the PK-PD model; (4) there is no dosing-rate-dependent or dosing-route-dependent pharmacological effect of disopyramide.
We studied here the antiallergic effect of apple condensed tannins (ACT) administered orally to a type I allergy model mouse transplanted with an IGEL a2 hybridoma secreting anti-2, 4, 6-trinitrophenyl (TNP) immunoglobulin E (IgE). The oral administration of ACT significantly inhibited the ear swelling responses at 1 h after antigen-stimulation with picryl chloride. The response was dose dependent within 0.1 to 10 mg/mouse. The inhibition of the ear swelling response reached the maximal level (90% inhibition) when ACT was administered 2 h before the antigen challenge. These findings suggest that ACT has an antiallergic effect on type I allergic symptoms.
The intraperitoneal administration of epinephrine (EP) to mice caused a significant increase in the blood glucose level and a significant decrease in the liver glycogen content 1 h after its administration at 0.6 mg/kg (blood glucose; p<0.01, liver glycogen; p<0.01). The liver type glucose transporter (GLUT2) mRNA expression and protein content from mouse liver significantly increased in the intraperitoneally EP-treated mice when compared to that in normal mice (mRNA; p<0.01, protein; p<0.01). These results suggest that the hyperglycemic effect of EP is due, at least in part, to the increase of GLUT2 protein synthesis.
The effect of zaldaride on acetylcholine-induced colonic electrolyte secretion was examined. The short-circuit current response to acetylcholine was partially reduced by tetrodotoxin, a neuronal blocker, and was completely inhibited by atropine, an acetylcholine M receptor antagonist, in the rat colonic preparations. The tetrodotoxin sensitive effect was significantly inhibited by zaldaride, whereas the tetrodotoxin insensitive effect was not affected. Acetylcholine release from synaptosomes of submucosal nerves of guinea-pig colon was significantly reduced by zaldaride. Zaldaride may reduce colonic electrolyte secretion by acetylcholine due to the inhibition of acetylcholine release from synaptosomes of colonic submucosal nerves.
Blomhotin is a novel peptide (pGlu1-Gly2-Arg3-Pro4-Pro5-Gly6-Pro7-Pro8-Ile9-Pro10-Arg11) which has been isolated from the venom of Agkistrodon halys blomhoffii and exhibits contractile activity on rat stomach fundus. We carried out a structure-activity study of blomhotin and its related peptides, and the findings suggested that the N-terminal portion of blomhotin is mainly responsible for affinity for the blomhotin receptor, whereas the C-terminal portion of blomhotin, Pro-Ile-Pro-Arg, is responsible for complete activation of the blomhotin receptor in the rat stomach fundus. In particular, the amino acids at positions 9 and 11 of blomhotin appear to be essential for binding and intrinsic activity. Using knowledge gained from this structure-activity analysis, we have identified photoactive blomhotin analogues that have sufficient biological activity to probe the target molecule of blomhotin.
We report the successful application to human venous blood of a novel method developed to purify rabbit polymorphonuclear neutrophils (PMNs) from whole blood. Human PMNs were separated from whole blood after sedimentation with dextran and histopaque density gradient centrifugation. 3.92±0.26×106 PMNs per ml of blood was harvested. The purity of the preparation was 92.00±1.10%. The PMNs isolated were capable of generating a high amount of reactive oxygen species (ROS) and elastase after stimulation with phorbol 12-myristate 13-acetate (PMA) : 13.43±0.3μM of O-2, 9.62±0.15μM of H2O2 and 5.48±0.01μM of elastase. This method gives equivalent yield and viability when applied to isolating human or rabbit PMNs, in comparison with standard methods used to isolate human PMNas. Our method could be usefully exploited for comparative studies of rabbit and human PMNs with a cellular model of inflammatory oxidative stress in which the monitoring parameters are ROS and elastase. Thus, the results of animal (rabbit) studies can be extended to human diseases.
We attempted to develop an experimental system for evaluation of the influence of stress on small intestinal motility using a radionuclide, 51Cr, and an acute restraint stress model. Each rat was immobilized in an adjustable restraint device for 1 to 5 h. The rat was given 51Cr immediately after the end of stress loading through a catheter inserted into the duodenum, and sacrificed 20 min after administration. The small intestine was removed and the 51Cr radioactivity was continuously monitored with an NaI-scintillation survey meter. The small intestinal motility was estimated by the distance of the radioactive peak from the top of the duodenum. The small intestinal motility was significantly inhibited by 3 h-restraint stress. This experimental system is easy, rapid, and simple for the evaluation of the effect of stress on small intestinal motility.
Substituted phenylazo and phenylazoxy compounds were systematically prepared and their anti-androgenic activity was measured in terms of (1) the growth-inhibiting effect on an androgen-dependent cell line, SC-3, and (2) the binding affinity of nuclear androgen receptor. Generally, azo/azoxy compounds showed cell toxicity, and the growth-inhibiting effects on SC-3 cells correlated with the toxicity. However, some compounds, including 4, 4'-dinitroazobenzene (25), 4, 4'-dimethoxyazobenzene (33), and 2, 2'-dichloroazoxybenzene (47), possessed potent anti-androgenic activity without apparent cell toxicity.
Gallic acid derivatives with a lipophilic group (hydrogenated farnesyl gallate, lauryl gallate, gallic acid laurylamide and cholesteryl gallate) were examined for their ability to induce apoptosis in human monoblastic leukemia U937 cells. Farnesyl ester derivative is the most potent apoptosis inducer among the compounds examined. The results suggest that lipid derivatives can augment the apoptosis-inducing activity of gallic acid depending on the structure. These findings will provide useful information in developing anti-cancer agents.
An oral administration of γ-tocotrienol (γ-T3) or γ-tocopherol (γ-Toc) to male rats caused an increase of the concentration of 2, 7, 8-trimethyl-2-(β-carboxyethyl)-6-hydroxy chroman (LLU-α, γ-CEHC), a natriuretic compound, in plasma with a Tmax of 9 h. The configuration at C-2 of LLU-α produced from γ-T3 or γ-Toc was assigned as S-form by an HPLC equipped with a chiral column. These data indicated that LLU-α was produced not only from γ-Toc but also γ-T3, without racemization at C-2 in rats.