A representative mucilage, called Hibiscus-mucilage RL, was isolated from the leaves of Hibiscus rosa-sinensis L. It was homogeneous on electrophoresis, and its molecular mass was estimated to be roughly 1.0×107. Its intrinsic viscosity value in aqueous solution was 23.2. The major constituent is an acidic polysaccharide composed of L-rhamnose : D-galactose : D-galacturonic acid : D-glucuronic acid in the molar ratio of 5 : 8 : 3 : 2. Methylation analysis, partial hydrolysis and nuclear magnetic resonance studies indicated its main structural features including a unique backbone chain composed of α-1, 4-linked D-galactosyl α-1, 2-linked L-rhamnosyl α-1, 4-linked D-galacturonic acid units. The mucilage showed considerable anti-complementary activity.
The mechanism of enhancement of tryptic digestion of insulin by empty liposomes was studied using HPLC analysis, gel filtration (insulin binding to the liposome and lipid transfer to the insulin) and an electrokinetic study using the zeta meter (trypsin binding to the liposome). Soybean phosphatidylcholine (PC), phosphatidic acid (PA) [PA/PC=1/9] and stearyl amine (StA) [StA/PC=1/9] were used as neutral, negatively charged and positively charged liposomes, respectively.Tryptic digestion of insulin was enhanced by reducing the liposome size from 150 to 40 nm when neutral empty liposomes were used. The amount of insulin bound to neutral empty liposomes increased on reducing liposome size. Nevertheless, no strong evidence of trypsin binding to neutral empty liposomes was obtained.The amount of liposome-bound insulin was greater for PC than StA/PC and PA/PC, and the amount of lipids transferred to insulin decreased in the following order;StA/PC>PA/PC>PC. These findings suggest that the positively charged liposome did not enhance tryptic digestion, because insulin was protected from tryptic digestion by surrounding lipids from positively charged liposomes (StA/PC). Trypsin bound to the PA/PC liposomes, but not to the PC or Sta/PC liposomes.
Zn2+-Dependent acid phosphatase (Zn2+-APase) was purified to homogeneity from bovine brain. The apparent molecular weight of the enzyme was estimated to be about 62000 by gel filtration and 31000 by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The enzyme exhibited an isoelectric point of approximately 4.8. The enzyme required Zn2+ ions for catalytic activity, but other cations had little or no effect. The maximum enzyme activity was obtained in the presence of about 5mM of Zn2+ at pH 5.5 in 50mM 2-(N-morpholino)ethanesulfonic acid-NaOH buffer. The enzyme significantly catalyzed the hydrolysis of p-nitrophenyl phosphate, phenyl phosphate, and phosphotyrosine. The enzyme was also active for myo-inositol-2-monophosphate and adenosine 2'-monophosphate of the other common phosphate esters tested, though significantly less active than for p-nitrophenyl phosphate. The optimum activity pH of the enzyme was around 5.5 with p-nitrophenly phosphate and myo-inositol-2-monophosphate. The enzyme was resistant to fluoride ions.Two types of Zn2+-APases, a high molecular weight (molecular weight, Mr., about 110000) and a low molecular weight (Mr., about 62000) type, were found to exist in various tissues of rat. Brain, lung, spleen, stomach, heart, skeletal muscle, and erythrocytes contained only the lower molecular weight type. On the other hand, liver and kidney contained mainly the higher molecular weight type, and the small intestine contained significant quantities of the both types.
A plasmid-cured strain of the marine Vibrio alginolyticus 138-2 retains a respiration-drive Na+ pump. Examinations of several strains of V. alginolyticus and V. parahaemolyticus revealed that these marine Vibrio always possessed the respiration-driven Na+ pump irrespective of the presence or absence of plasmids. These results strongly suggested that the genes for the Na+ pump were encoded by chromosomal DNA.
A morphine UDP-glucuronyltransferase was purified from liver microsomes of untreated Sprague-Dawley rats. A new gel, ω-(β-carboxypropionylamino)octyl Sepharose 4B, was prepared by coupling monomethylsuccinate with ω-aminooctyl Sepharose 4B and this was used as an efficient tool for the separation of microsomal enzymes. Emulgen 911 solubilized microsomes were applied to a column packed with the gel and eluted at pH 7.4 while increasing KCl concentration in a stepwise manner. An isoform was further purified with UDP-hexanolamine Sepharose 4B gel. The purified UDP-glucuronyltransferase (morphine UGT of untreated rat, morphine UGTUT) exhibited a molecular weight of 52000 on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and was capable of glucuronidating the 3-hydroxyl group of morphine. The isoform catalyzed to a small extent the glucuronidation of 4-hydroxybiphenyl; however, no glucuronidation activity towards androsterone, testosterone, bilirubin, 4-nitrophenol and the 6-hydroxyl group of morphine was observed. The difference in properties, compared with morphine UGT (molecular weight 56000)which was purified previously from phenobarbital-treated rats, is discussed.
The effect of protoporphyrin (PP) administration on the activities of enzymes related to and/or involved in lipid peroxidation and on the content of reduced glutathione (GSH) was investigated in rat liver. PP, at an intravenous does of 20 mg/kg, increased GSH content, caused a weak suppression of NADPH-cytochrome c reductase activity and a slight increase of ν-glutamyl transpeptidase activity 24h after dosing, but had no effect on the activities of other enzymes such as xanthine oxidase, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase, ν-glutamylcysteine synthetase or glutathione synthetase. Treatment of rats with diethyl maleate following PP injection resulted in the disappearance of antioxidative action of PP. Furthermore, sinusoidal, but not canalicular, efflux of the hepatic GSH was decreased by the PP treatment. The increase of liver GSH content by PP treatment due to the decrease of sinusoidal efflux of GSH from the liver, thus would be involved in the exertion of antioxidative action of PP.
The effect of morphine on tumor growth of EL-4 leukemia in C57BL/6 mice and of Sarcoma 180 carcinoma in ddY mice was studied. Local subcutaneous tumor growth was enhanced by morphine (10 mg/kg, s.c.) given daily for 10d. This effect was inhibited by preadministration of the opioid antagonist naloxone. However, naloxone alone had no significant effect on tumor growth. Morphine also enhanced tumor growth in C57BL/6 mice inoculated i.p. with P388 as well as Meth-A cell in Balb/c mice. However, incubation of morphine with cultures of EL-4, P388, MM-46 and Meth-A cells failed to enhance tumor growth. Mice given morphine displayed marked atrophy and reduced cellularity of the spleen and thymus. The humoral response to sheep erythrocytes and T- and B-cell responses to foreign antigens were suppressed, and the lymphocyte proliferative response to T- and B-cell mitogens (concanavalin A and bacterial lipopolysaccharide, respectively) was attenuated. Morphine exerted an inhibitory effect on the immune response which was antagonized by the concomitant administration of naloxone. These data suggest that the enhancement of tumor growth by the administration of morphine is the result of a overall immunosuppresive effect. The significance of the immunomodulatory effect of morphine is discussed in this report.
Gastric chief cells were isolated from the rat stomach in an attempt to identify those involved in the mechanism of action of somatostatin on pepsinogen secretion. The effects of several kinds of secretagogues on cytosolic free Ca2+ concentration ([Ca2+]i) were examined in the rat chief cells. Carbachol and cholecystokinin octapeptide (CCK-8)markedly induced[Ca2+]i increase, while histamine, gastrin I and secretin did not. Carbachol and CCK-8 also stimulated pepsinogen secretion. A similar dose-response relationship was seen in carbachol-and CCK-8-induced [Ca2+]i increase and pepsinogen secretion. Somatostatin did not inhibit carbachol-or CCK-8-induced [Ca2+]i increase, but did inhibit carbachol- and CCK-8-induced pepsinogen secretion by 30 and 50%, respectively.
The effects of nifedipine and nicardipine on isoproterenol-stimulated gluconeogenesis from 10mM lactate were examined in serum-free cultures of rat hepatocytes. Nifedipine and nicardipine (10-7-10-5M) significantly potentiated the isoproterenol-stimulated gluconeogenesis from 10mM lactate by increasing intracellular cAMP levels. In contrast, diltiazem and verapamil (10-7-10-6M) did not potentiate it. 1-Methyl-3-isobutylxanthine (IBMX; 10-6-10-4M), which is known to inhibit phosphodiesterase activity, dose-dependently potentiated isoproterenol-stimulated gluconeogenesis from lactate in serum-free cultures of rat hepatocytes. In parallel, IBMX also increased the isoproterenol-induced intracellular concentrations of cAMP in a dose-dependent manner. These results suggest that the possible mechanism by which nifedipine and nicardipine potentiate the isoproterenol-stimulated gluconeogenesis is related to the increase of cAMP levels through the inhibition of cAMP phosphodiesterase.
The profile of actions of dihydroetorphine (DHE) concerning antinociception, tolerance and dependence was compared with those of morphine in mice. DHE at 1, 5, 10 or 20μg/kg produced an antinociceptive effect in a dose dependent manner and 10μg/kg was nearly equipotent to that of 10mg/kg of morphine. The antinociceptive effect of both drugs was completely suppressed by 1mg/kg of naloxone, while neither 10mg/kg of naltrindole nor 1mg/kg of nor-binaltorphimine had any suppressive effect. Mice tolerant to morphine antinociception were tolerant to DHE and vice versa. The naloxone-sensitive, locomotor accelerating activity was progressively enhanced by daily administration of DHE and morphine and a cross reverse tolerance developed between these compounds, suggesting that common mechanisms, especially mediating opioid receptors, underlay the activity enhancement. The development of physical dependence as evidenced by naloxone precipitated withdrawal signs, however, was not observed with daily treatment with DHE, 10, 20 and 100μg/kg for 6d. Thus, we demonstrated that DHE produces the antinociceptive effect mediated through μ opioid receptors without causing development of a physical dependence, suggesting that it is safe to use in the clinical therapy of patients suffering severe pain such as that accompanying cancer.
The antitumor activity of a nucleotide derivative, 5'-(1, 2-dipalmitoyl-sn-glycero-3-phospho)-5-fluorouridine(TJ14026), was confirmed following both intraperitoneal and oral administration against a number of murine experimental tumor systems in vivo, which included Meth A fibrosarcoma, B16 melanoma, 5-fluorouracil (5-FU) resistant P388 leukemia, P815 mastocytoma and L5178Y-ML lymphoma. Successive i.p. injections of a small dose(10mg/kg/d×10) or intermittnet i.p. injections of a larger dose (50mg/kg/d×3) were equally effective against the solid form of Meth A fibrosarcoma. Intraperitoneal injection of TJ14026 prolonged the life of mice with 5-FU resistant P388 leukemia. Oral administration of TJ14026 was also effective against P815 mastocytoma and L-5178Y-ML lymphoma in the liver, an P388 leukemia metastasized to the lymph nodes. Glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) levels were elevated in the serum of un-treated mice bearing P815 mastocytoma but not in mice treated with TJ14026.
The preventive effects of a traditional Chinese medicine Sho-saiko-to (Kampo prescription, TJ-9) were determined from oxygen toxicity and membrane damage in liver during endotoxemia. The liver lipid peroxide level and xanthine oxidase activity 18h after administration of endotoxin (6mg/kg, i.p.) to TJ-9 (500mg/kg/d, p.o.)-pretreated mice were markedly lower than that in endotoxin-treated mice, whereas the administration of TJ-9 significantly increased superoxide dismutase and glutathione peroxide activities in liver of endotoxin-injected mice. In the mice pretreated with a TJ-9, the levels of α-tocopherol and nonprotein SH in liver tissue 18h after endotoxin injection were markedly increased as compared to those in endotoxin-treated mice. Leakages of acid phosphatase and lactate dehydrogenase isozyme in serum were markedly lower in endotoxin-TJ-9-treated mice than those in mice given endotoxin. The administration of TJ-9 clearly prevented the membrane protein damage arising from endotoxin challenge. Kampo prescription Sho-saiko-to thus appears to protect the liver plasma mambrane from injury by free radicals which occur in a tissue ischemic state during endotoxemia.
Seven highly active inhibitors against carbonic anhydrase (CA, EC 184.108.40.206), punicalin (2), punicalagin (3), granatin B (5), gallagyldilactone (7), casuarinin (8), pedunculagin (9) and tellimagrandin I (10), and four weakly active inhibitors, gallic acid (1), granatin A (4), corilagin (6) and ellagic acid (11), were isolated from the pericarps of Punica granatum L. (Punicaceae). They are ellagitannins. The type of inhibition by 3 and 7 using p-nitrophenyl acetate as a substrate, is noncompetitive. The structure-activity relationship of inhibitory effects on CA is discussed.
Glucagon has been demonstrated to stimulate the uptake of bile acid in isolated rat hepatocytes (Am. J. Physiol., 249, G427(1985)). In the present study, we determined the influence of glucagon on the hepatic transport of a bile acid, taurocholate (TCA), in isolated rat livers. A single-pass perfusion and a rapid-injection, multiple indicator dilution method were employed. The hepatic availability at steady-state was 0.04. With the presence of glucagon in the perfusate(from 10-9 to 10-7M), the bile flow rate was stimulated by 30%, while hepatic availability was decreased from 0.04 to 0.02 with a stepwise increase in glucagon concentration. Thirty min after the infusion glucagon (300nM), [3H]TCA and [14C]inulin were injected in a bolus state into the portal vein, and the outflow was collected at 1.0s intervals over 30s. Glucagon decreased the instantaneous hepatic availability by 50% compared to the control level, and was thus compatible with the steady-state experiments. In the control experiment, the influx clearance (PSinf) was 20 times higher than the efflux clearance (PSeff). Glucagon (300nM) in the perfusate enhanced PSinf by 50% of the control, whereas sequestration clearance (CLseq) and the biliary excretion rate constant remained unchanged. PSeff was stimulated to 2 times the control, but still remained much smaller than CLseq. Based on the comparison of PSinf, PSeff and CLseq, the rate-determining process of TCA hepatic elimination was the influx process in both the presence and absence of glucagon. Taken together, the enhancement of the influx process was responsible for the decrease in TCA hepatic availability caused by glucagon. Glucagon also enhanced the bile flow rate, but did not alter the biliary excretion rate of TCA, suggesting that glucagon might stimulate the bile acid independent bile flow.
N-[[[4-(5-Bromo-2-pyrimidinyloxy)-3-chlorophenyl]amino]carbonyl]-2-nitrobenzamide (HO-221) is presently under development as an oral antivancer agent with a novel mode of action. However, HO-221 exhibits extremely poor bioavailability after oral administration because it is only slightly soluble in water (0.055μg/ml at 37°C). Our previous study revealed that the micronization of HO-221 to the submicron region improved this oral bioavailability. In this study, the oral pharmacokinetics of this micronized HO-221 was investigated in rats, dogs and monkeys. After oral administration, the agent was moderately absorbed with the Tmax of 6.5-8.0, 17.3-20.0 and 12.0h, and eliminated with the terminal half-lives of 11.9-15.0, 66.8-78.3 and 42.3h in rats, dogs and monkeys, respectively. The bioavailability was incomplete (3.7-21.4%). In rats, the plasma concentration did not increase proportionally with increasing oral doses. In dogs, food enhanced the bioavailability 2.2-fold with a standard meal and 3.6-fold with a high fatty meal as compared with fasting conditions.
We investigated the usefulness of a liposome composed of lipid components of stratum corneum as a system to evaluate the enhancing ability of various penetration enhancers. Changes in the lipid fluidity of the model lipid liposome membrane, consisting of ceramide (40%), cholesterol (25%), palmitic acid (25%) and cholesterol 3-sulfate (10%), by the addition of 1-dodecylazacycloheptan-2-one (Azone), oleic acid (OA) or dimethyl sulfoxide (DMSO) were measured by a fluorescence polarization method using 1, 6-diphenyl-1, 3, 5-hexatriene, dansylhexadecylamine and cholesteryl anthracene-9-carboxylate as probes for the hydrophobic lipid, the polar head and cholesterol regions of the lipid bilayer, respectively. The order of lipid fluidizing ability was suggested to be Azone>OA>DMSO. An in vitro permeation study of six β-blocking agents, propranolol, metoprolol, timolol, pindolol, nadolol and atenolol, was carried out to estimate the enhancing effect of the anhancers using rat abdominal skin. Azone showed a strong facilitating effect on the drug permeation and the effect of OA was weaker than that of Azone. DMSO showed little effect unless a high concentration of over 60% (w/v) was employed. The basis for these enhancing mechanisms is the change in diffusion constant of a drug in the rat skin.These results were consistent with those obtained from the lipid fluidity measurement, that is to say, the stronger the increment effect of the enhancer on the fluidity of the model lipid liposome is, the larger is the D value for the drug in the skin. Applicability of the model lipid liposome in evaluating the penetration enhancer was thus demonstrated.
Intraperitoneal administration of lauric acid (C12) at the high doses, 100-1000μmol/kg, showed weak but dose-dependent antinociceptive effect in mice. Pretreatment of the animals with 0.1μmol/kg of i.p. C12 tended to suppress the antinociceptive effect of 7mg/kg of s.c. morphine and daily combination of this dose of C12 with 10mg/kg of s.c. morphine blocked the development of antinociceptive tolerance to morphine. However, increasing or decreasing of the dose of C12 resulted in the loss of its modulatory effect on morphine. The strict dose-dependency of C12 in its action on morphine suggests that there is a regulatory role for C12, a medium length straight chain fatty acid, in the endogenous pain inhibitory system.
The present study describes the activity of Ca2+-ATPase in liver plasma membrane and cytosolic-free Ca2+ concentration ([Ca2+]i) in an individual vital cell in mouse liver 18h after endotoxin administration. Ca2+-ATPase activity in liver plasma membrane in the poisoned mice was markedly decreased to 28% of that in the control. The membrane protein damage in liver was found mostly in the molecular weight (M.W.) regions near 60000-150000 in endotoxemic mice, and was markedly injured near 140000 (M. W. of Ca2+-ATPase in liver plasma membrane). The level of [Ca2+]i in liver cells in endotoxin-poisoned mice was greater at 18h postintoxication than that of the control.These findings suggest the possibility that the depression of Ca2+-ATPase activity in liver plasma membrane in mice may contribute to membrane damage caused by the endotoxin, and that the increase of [Ca2+]i in liver cytoplasm may partially explain various endotoxin-induced metabolic disorders.
Three major metabolites of mefenamic acid were isolated from the urine of a normal adult man receiving mefenamic acid orally. The structures of those metabolites were determined as glucuronides of mefenamic acid, its hydroxymethyl derivative, and its carboxylic acid derivative on the basis of spectral data.
Thiosalicylic acid (I) showed rather strong inhibitory activity on the growth of roots of all plants treated except Abelmoschus esculentus MOENCH at the concentration of 5.0×10-4M. This compound strongly inhibited the growth of the root of Echinochloa utilis OHWI et YABUNO even at the low concentration of 5.0×10-5M. Dihydro-2(3H)-thiophenone (VII) also exhibited inhibitory activity on the growth of roots of all plants treated except Glycine max MERRILL. Both compounds inhibited the germination of seeds of some plants at the concentration of 1.0×10-3M. In I-related compounds (I-V), methyl acetythiosalicylate (IV) had the strongest inhibitory activity, while in VII-related compounds (VII-XI), 4-hydroxy-2(5H)-thiophenone (VIII) showed the most potent inhibitory activity. The amount of chlorophyll in the cotyledon of Brassica campestris L. subsp. rapa Hook. f. et ANDERS treated with all compounds except tetrahydrothiophene (XI) was lower than that of the control group.