UVC-Protective Activity of Lemongrass Among 12 Fat-soluble Herbal Extracts: Rapid Decay Due to Cytotoxicity

BACKGROUND/AIM

The COVID-19 pandemic led to the rapid spread of the use of ultraviolet C (UVC) sterilizers in many public facilities. Considering the harmful effects of prolonged exposure to UVC, manufacturing of safe skin care products is an important countermeasure. In continuation of our recent study of water-soluble herbal extracts, the present study aimed at searching for anti-UVC components from fat-soluble herbal extracts.

MATERIALS AND METHODS

Human dermal fibroblast and melanoma cells were exposed to UVC (1.193 W/m2) for 3 min. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell-cycle analysis was performed using a cell sorter. UVC-protective activity was quantified by the selective index (SI), i.e., the ratio of the 50% cytotoxic concentration for unirradiated cells to the concentration that restored viability of UVC-treated cells by 50%.

RESULTS

Only lemongrass extract, among 12 fat-soluble herbal extracts, showed significant anti-UVC activity, comparable to that of lignified materials and tannins, but exceeding that of N-acetyl-L-cysteine and resveratrol. Lemongrass extract was highly cytotoxic, producing a subG1 cell population. During prolonged incubation in culture medium, the anti-UVC activity of lemongrass extract, sodium ascorbate and vanillic acid declined with an approximate half-life of <0.7, 5.4-21.6, and 27.8-87.0 h, respectively.

CONCLUSION

Removal of cytotoxic principle(s) from lemongrass extract is crucial to producing long-lasting UVC-protective effects.

Comprehensive Study of Anti-UVC Activity and Cytotoxicity of Hot-water Soluble Herb Extracts

BACKGROUND/AIM

COVID-19 pandemic caused the rapid dissemination of ultraviolet C (UVC) sterilization apparatuses. Prolonged exposure to UVC, however, may exert harmful effects on the human body. The aim of the present study was to comprehensively investigate the anti-UVC activity of a total of 108 hot-water soluble herb extracts, using human dermal fibroblast and melanoma cell lines, for the future development of skin care products.

MATERIALS AND METHODS

Exposure time to UVC was set to 3 min, and cell viability was determined using the MTT assay. Anti-UVC activity was determined using the selective index (SI), a ratio of 50% cytotoxic concentration for unirradiated cells to 50% effective concentration that restored half of the UVC-induced decrease of viability.

RESULTS

Dermal fibroblasts at any population doubling level were more resistant to UVC irradiation than melanoma cells. Both 49 herb extracts recommended by Japan Medical Herb Association (JAMHA) and 59 additional herb extracts showed comparable anti-UVC activity. SI values of selected herbs (Butterbur, Cloves, Curry Tree, Evening Primrose, Rooibos, Stevia, Willow) were several-fold lower than those of vitamin C and vanillin. Their potent anti-UVC activity was maintained for at least 6 h post irradiation, but declined thereafter to the basal level, possibly due to cytotoxic ingredients.

CONCLUSION

UVC sensitivity may be related to the growth potential of target cells. Removal of cytotoxic ingredients of herb extracts may further potentiate and prolong their anti-UVC activity.

Enhanced Cytotoxic Effects of Arenite in Combination with Active Bufadienolide Compounds against Human Glioblastoma Cell Line U-87

The cytotoxicity of a trivalent arsenic derivative (arsenite, As^III) combined with arenobufagin or gamabufotalin was evaluated in human U-87 glioblastoma cells. Synergistic cytotoxicity with upregulated intracellular arsenic levels was observed, when treated with As^III combined with arenobufagin instead of gamabufotalin. Apoptosis and the activation of caspase-9/-8/-3 were induced by As^III and further strengthened by arenobufagin. The magnitude of increase in the activities of caspase-9/-3 was much greater than that of caspase-8, suggesting that the intrinsic pathway played a much more important role in the apoptosis. An increase in the number of necrotic cells, enhanced LDH leakage, and intensified G₂/M phase arrest were observed. A remarkable increase in the expression level of γH2AX, a DNA damage marker, was induced by As^III+arenobufagin. Concomitantly, the activation of autophagy was observed, suggesting that autophagic cell death associated with DNA damage was partially attributed to the cytotoxicity of As^III+arenobufagin. Suppression of Notch signaling was confirmed in the combined regimen-treated cells, suggesting that inactivation of Jagged1/Notch signaling would probably contribute to the synergistic cytotoxic effect of As^III+arenobufagin. Given that both As^III and arenobufagin are capable of penetrating into the blood-brain barrier, our findings may provide fundamental insight into the clinical application of the combined regimen for glioblastoma.

Synthesis of 4,4-Disubstituted 3,4-Dihydropyrimidin-2(1H)-ones and -thiones, the Corresponding Products of Biginelli Reaction Using Ketone, and Their Antiproliferative Effect on HL-60 Cells

An efficient synthetic method for novel 4,4-disubstituted 3,4-dihydropyrimidin-2(1H)-ones 5 and -thiones 6 was developed. The cyclocondensation reaction of O-methylisourea hemisulfate salt 11 with 8 gives a tautomeric mixture of dihydropyrimidines 12 and 13 following acidic hydrolysis of the cyclized products to produce 5 in high yields. Thionation reaction of 5 at the 2-position smoothly proceeds to give 2-thioxo derivatives 6. These compounds 5 and 6, corresponding to the products of a Biginelli-type reaction using urea or thiourea, a ketone and a 1,3-dicarbonyl compound, have long been inaccessible and hitherto unavailable for medicinal chemistry. These methods are invaluable for the synthesis of 5 and 6, which have been inaccessible by conventional methods. Therefore, the synthetic methods established in this study will expand the molecular diversity of their related derivatives. These compounds were also assessed for their antiproliferative effect on a human promyelocytic leukemia cell line, HL-60. Treatment of 10 µM 6b and 6d showed high inhibitory activity similarly to 1 µM all-trans retinoic acid (ATRA), indicating that the 2-thioxo group and length of two alkyl substituents at the 4-position are strongly related to activity.

Effects of hot‑water extracts from 26 herbs on α‑glucosidase activity

α‑glucosidase is a key enzyme that plays a role in glucose absorption in the gastrointestinal tract, and the inhibition of its activity induces the prevention of postprandial hyperglycemia. Several α‑glucosidase inhibitors have been used as medicines for type 2 diabetes, but a similar effect is observed in natural resources, including traditional herbs and their phytochemicals. To identify the presence of the α‑glucosidase inhibitory activity in herbs, in which various functional effects have been known to occur, the present study investigated the effects of hot‑water extracts of 26 types of herbs on α‑glucosidase activity in an in vitro assay. The results indicated significant increases in the inhibition of α‑glucosidase activity in 1,000 µg/ml olive (P<0.01), white willow (P<0.01) and red rooibos hot‑water extracts. Furthermore, ≥50% inhibition of α‑glucosidase activity was determined to be significant in 1,000 µg/ml coltsfoot, green tea and bearberry hot‑water extracts. In addition, the effects of bearberry, green tea and coltsfoot hot‑water extracts on α‑glucosidase activity in vivo were evaluated according to the blood glucose levels (BGLs) in maltose and glucose load model rats. It was indicated that the administration of these three herb extracts significantly reduced the increasing BGLs after maltose loading until 0.5 h compared with the control group. However, only coltsfoot extract significantly reduced the increasing BGLs after glucose loading until 0.5 h compared with the control group. Thus, the present results may facilitate the understanding of a novel functionality in traditional herbs, which could be useful for the prevention of disease onset and progression, such as in hyperglycemia and type 2 diabetes.

Evaluation of Biological Activity of Mastic Extracts Based on Chemotherapeutic Indices

BACKGROUND

Most previous mastic investigators have not considered its potent cytotoxicity that may significantly affect the interpretation of obtained data. In the present study, we re-evaluated several biological activities of mastic extracts, based on chemotherapeutic indexes.

MATERIALS AND METHODS

Pulverized mastic gum was extracted with n-hexane and then with ethyl acetate or independently with methanol or n-butanol. Tumor specificity (TS) of the extracts was determined by their cytotoxicity against human malignant and non-malignant cells. Antibacterial activity was determined by their cytotoxicity against bacteria and normal oral cells. Antiviral activity was determined by their protection of viral infection and cytotoxic activity. Cytochrome P-450 (CYP) 3A4 activity was measured by β-hydroxylation of testosterone.

RESULTS

Ethyl acetate extract showed slightly higher tumor specificity (TS=2.6) and one order higher antibacterial activity (selectivity index (SI)=0.813) than other extracts (TS=1.4-2.5; SI=0.030-0.063). All extracts showed no anti-human immunodeficiency virus (HIV) activity, but some anti-herpes simplex virus (HSV) activity, which was masked by potent cytotoxicity. They showed strong inhibitory activity against CYP3A4.

CONCLUSION

Ethyl acetate extraction following the removal of cytotoxic and CYP3A4 inhibitory substances by n-hexane can enhance antitumor and antibacterial activity of mastic.

Rosehip inhibits xanthine oxidase activity and reduces serum urate levels in a mouse model of hyperuricemia

Rosehip, the fruit of Rosa canina L., has traditionally been used to treat urate metabolism disorders; however, its effects on such disorders have not been characterized in detail. Therefore, the present study investigated the effects of hot water, ethanol and ethyl acetate extracts of rosehip on xanthine oxidase (XO) activity in vitro. In addition, the serum urate lowering effects of the rosehip hot water extract in a mouse model of hyperuricemia (male ddY mice, which were intraperitoneally injected with potassium oxonate) were investigated. Furthermore, the influence of rosehip hot water extract on CYP3A4 activity, which is the most important drug-metabolizing enzyme from a herb-drug interaction perspective, was investigated. Rosehip extracts of hot water, ethanol and ethyl acetate inhibited XO activity [half maximal inhibitory concentration (IC50) values: 259.6±50.6, 242.5±46.2 and 1,462.8±544.2 µg/ml, respectively]. Furthermore, the administration of 1X rosehip hot water extract significantly reduced the levels of serum urate at 8 h, which was similar when compared with the administration of 1 mg/kg allopurinol. Rosehip hot water extract only marginally affected CYP3A4 activity (IC50 value, >1 mg/ml). These findings indicate that rosehip hot water extract may present as a functional food for individuals with a high urate level, and as a therapeutic reagent for hyperuricemic patients.

Efficient utilization of licorice root by alkaline extraction

Compared to studies of water extracts of plants, those utilising alkaline extracts are limited. Both water and alkaline extracts from licorice root were compared regarding their biological activities. Licorice root was successively extracted first with water or alkaline solution (pH 9 or 12), and the alkaline (pH 12.0) extract was further separated into 50% ethanol-soluble and -insoluble fractions. Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Antibacterial activity against Porphyromonas gingivalis 381 was determined by turbidity assay. Cytochrome P-450 (CYP)3A4 activity was measured by β-hydroxylation of testosterone using human recombinant CYP3A4. Radical intensity of superoxide and hydroxyl radicals was determined by electron spin resonance spectroscopy. Alkaline extraction yielded slightly higher amounts of dried materials compared to water extraction. Alkaline extract showed higher anti-HIV and antibacterial activities, and similar magnitudes of CYP3A4 inhibitory and superoxide and hydroxyl radical-scavenging activities, compared to water extract. When alkaline extract was fractionated by 50% ethanol, anti-HIV activity was recovered from the insoluble fraction representing approximately 3% of the alkaline extract, whereas antibacterial activity was concentrated in the soluble fraction rich in glycyrrhizid acid, flavanones and chalcones. All extracts and sub-fractions led to bimodal hormetic dose-response (maximum hormetic response=238%) on the bacterial growth. The present study demonstrated the superiority of alkaline extraction over water extraction for preparing anti-HIV and antibacterial agents at higher yield from licorice root.

Signal transduction mechanism for potentiation by α1- and β2-adrenoceptor agonists of L-ascorbic acid-induced DNA synthesis and proliferation in primary cultures of adult rat hepatocytes

We investigated the effects of α- and β-adrenoceptor agonists on L-ascorbic acid-induced hepatocyte DNA synthesis and proliferation in primary cultures of adult rat hepatocytes. The results showed that phenylephrine (10(-6) M) and metaproterenol (10(-6) M) alone did not induce hepatocyte DNA synthesis and proliferation. However, when combined with L-ascorbic acid (10(-6) M), these adrenoceptor agonists potentiated the hepatocyte DNA synthesis and proliferation induced by L-ascorbic acid. Then intracellular signal transduction mechanisms for the effects of phenylephrine and metaproterenol on L-ascorbic acid-induced hepatocyte mitogenesis were examined. Western blot analysis showed that phenylephrine and metaproterenol did not potentiate L-ascorbic acid-induced insulin-like growth factor I receptor tyrosine kinase phosphorylation. In contrast, they both significantly potentiated L-ascorbic acid-induced extracellular-signal regulated kinase-2 (ERK2) phosphorylation within 5 min. Moreover, cell-permeable second messenger analogs phorbol ester (10(-7) M) and 8-bromo cAMP (10(-7) M) mimicked the effects of phenylephrine and metaproterenol on L-ascorbic acid-induced ERK2 phosphorylation. The effects of these adrenoceptor agents were specifically antagonized by GF109203X and H-89, respectively. These results indicate that activation of ERK2 via protein kinas C and protein kinase A represents a mechanism for potentiation of L-ascorbic acid-induced hepatocyte DNA synthesis and proliferation in primary cultures of adult rat hepatocytes.

Mechanism-based inhibition of recombinant human cytochrome P450 3A4 by tomato juice extract

This study investigates whether tomato juice can inhibit cytochrome P450 (CYP) 3A4-mediated drug metabolism. Three commercially available, additive-free tomato juices, along with homogenized fresh tomato, were analyzed for their ability to inhibit testosterone 6β-hydroxylation activity using human recombinant CYP3A4. Results were compared to that of grapefruit juice. Ethyl acetate extracts of the tomato juices moderately reduced residual activity of CYP3A4 testosterone 6β-hydroxylation activity by 19.3-26.2% with 0-min preincubation. Residual activity was strongly reduced by 69.9-83.5% at 20-min preincubation, a reduction similar to that of grapefruit juice extract, known to contain constituents of mechanism-based inhibitors. One juice extract (tomato juice C) showed irreversible dose- and preincubation time-dependent and partial nicotinamide adenine dinucleotide phosphate (NADPH)-dependent inhibition of CYP3A4 activity. Furthermore, we examined whether the CYP3A4 inhibitory effect of tomato juice was substrate dependent by examining midazolam 1'-hydroxylation activity and nifedipine oxidation activity, in addition to testosterone 6β-hydroxylation activity. Tomato juice showed a potent inhibitory effect on nifedipine oxidation activity, which was comparable to that on testosterone 6β-hydroxylation activity; however, it showed a weak inhibitory effect on midazolam 1'-hydroxylation activity. We conclude that tomato juice contains one or more mechanism-based and competitive inhibitor(s) of CYP3A4. Additionally, significant CYP3A4 inhibitory activity did not result from lycopene, a major compound in tomato. Although the active compound was uncertain, a strong CYP3A4 inhibitory activity was observed in other solanaceous plants, i.e., potato, eggplant, sweet pepper, and capsicum. Therefore, responsible compounds in tomato are likely commonly shared among solanaceous vegetables.

Differential induction of stearoyl-CoA desaturase 1 and 2 genes by fibrates in the liver of rats

The administration of fibrates (fenofibrate, bezafibrate and clofibric acid) to rats induced stearoyl-CoA desaturase (SCD) in the liver, and increased relative expression of mRNAs encoding SCD1 and SCD2 in dose- and time-dependent manners. The magnitudes of the increases in SCD2 mRNA level caused by fenofibrate and clofibric acid were much higher than those of SCD1 at relatively higher doses of the fibrates, and a relatively long time (7 or 14 d) was required for significant induction of SCD2 mRNA expression compared with that of SCD1. Although the absolute number of transcripts for SCD2 was 1,800 times lower than that of SCD1 in the control liver, it was strikingly increased by fibrates. These results suggest that differential regulations operate for the gene expression between SCD1 and SCD2, and that the physiological significance of SCD2 is distinct from that of SCD1 in the liver.

Biological activity of SE-10, granulated powder of Sasa senanensis Rehder leaf extract

BACKGROUND

We have previously reported that alkaline extract of Sasa senanensis leaves (SE) showed potent anti-HIV, anti-UV and radical scavenging activity. In the present study, we investigated the biological activities of SE-10, a granulated powder of SE supplemented with lactose, lactitol, trehalose and tea extract.

MATERIALS AND METHODS

Cell viability of mock-infected, HIV-infected, and UV-irradiated cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Scavenging activity of superoxide anion and hydroxyl radicals was determined by electron-spin resonance spectroscopy. Cytochrome P-450 (CYP)3A4 activity was measured by β-hydroxylation of testosterone in human recombinant CYP3A4.

RESULTS

SE-10 had slightly higher anti-HIV and anti-UV activities, but slightly lower radical-scavenging and CYP3A4-inhibitory activities, as compared with SE.

CONCLUSION

The present study demonstrates that the biological activities of SE were well preserved during the manufacturing process of SE-10.

Comparative study of biological activity of three commercial products of Sasa senanensis Rehder leaf extract

BACKGROUND

We have previously reported that alkaline extract of Sasa senanensis leaves (SE) has several biological activities characteristic of lignin-carbohydrate complex (LCC). In the present study, we compared the biological activity of three commercially available products of SE (products A, B and C).

MATERIALS AND METHODS

Cell viability of mock-infected, HIV-infected, UV-irradiated cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Radical intensity was determined by electron spin resonance spectroscopy. Cytochrome P-450 (CYP)3A4 activity was measured by β-hydroxylation of testosterone in human recombinant CYP3A4.

RESULTS

Product A is a pure SE that contains Fe(II)-chlorophyllin, whereas products B and C contain Cu(II)-chlorophyllin and less LCC. Product C is supplemented with ginseng and pine (Pinus densiflora) leaf extracts. Product A exhibited 5-fold higher anti-HIV, 4-fold higher anti-UV, 5-fold higher hydroxyl radical-scavenging, and 3-fold lower CYP3A4 inhibitory activities as compared to those of product B, and 5-fold higher, 1.5-fold higher, comparable, and 7-fold lower activities, respectively, as compared to those of product C.

CONCLUSION

The present study demonstrates for the first time the superiority of product A over products B and C, suggesting the beneficial role of LCC and Fe(II)-chlorophyllin.

Effects of perfluorinated fatty acids with different carbon chain length on fatty acid profiles of hepatic lipids in mice

Alterations by perfluorinated fatty acids (PFCAs) with a chain length of 6-9 carbons in the fatty acid profile of hepatic lipids of mice were investigated. The characteristic changes caused by all the PFCAs examined were increases in the contents and proportions of oleic acid (18 : 1), palmitoleic acid (16 : 1) and 8,11,14-eicosatrienoic acid (20 : 3) in hepatic lipids. Hepatic contents of palmitic acid were also increased by the treatments with the PFCAs. These effects were almost dependent on the hepatic concentrations of PFCA molecules regardless of their carbon chain length. Perfluorooctanoic acid elevated the expressions of mRNA encoding acetyl-CoA carboxylase, fatty acid synthase, malic enzyme, stearoyl-CoA desaturase (SCD) (SCD1 and 2), chain elongase (ELOVL5), Δ6 desaturase (Fads2), 1-acylglycerophosphocholine acyltransferase (LPCAT) (LPCAT3). The four PFCAs examined induced microsomal SCD and LPCAT in hepatic concentration-dependent manners regardless of carbon chain length. One linear regression line was confirmed between LPCAT activity and hepatic concentration of PFCA at wide range of the concentration, whereas the induction of SCD was saturable at relatively low concentration of PFCAs. These results suggest (i) that PFCAs with a chain length of 6-9 carbons change the fatty acid profile of hepatic lipids by increasing contents and proportions of 16 : 1, 18 : 1 and 20 : 3, (ii) that these alterations in fatty acid profile are caused by up-regulation of SCD, de novo fatty acid synthesis, chain elongase and Δ6 desaturase and (iii) that the mechanism underlying SCD induction is, in part, mediated through peroxisome proliferator-activated receptor α.

Clofibric acid increases the formation of oleic acid in endoplasmic reticulum of the liver of rats

The effects of 2-(4-chlorophenoxy)-2-methylpropionic acid (clofibric acid) on the formation of oleic acid (18:1) from stearic acid (18:0) and utilization of the 18:1 formed for phosphatidylcholine (PC) formation in endoplasmic reticulum in the liver of rats were studied in vivo. [¹⁴C]18:0 was intravenously injected into control Wistar male rats and rats that had been fed on a diet containing 0.5% (w/w) clofibric acid for 7 days; and the distribution of radiolabeled fatty acids among subcellular organelles, microsomes, peroxisomes, and mitochondria, was estimated on the basis of correction utilizing the yields from homogenates of marker enzymes for these organelles. The radioactivity was mostly localized in microsomes and the radiolabeled fatty acids present in microsomes were significantly increased by the treatment of rats with clofibric acid. The formation of radiolabeled 18:1 in microsomes markedly increased and incorporations of the formed [¹⁴C]18:1 into PC and phosphatidylethanolamine in microsomes were augmented in response to clofibric acid. The [¹⁴C]18:1 incorporated into PC was mostly located at the C-2 position, but not the C-1 position, of PC, and the radioactivity in 18:1 at the C-2 position of PC was strikingly increased by clofibric acid. These results obtained from the in vivo experiments directly link the findings that clofibric acid treatment induces microsomal stearoyl-CoA desaturase and 1-acylglycerophosphocholine acyltransferase in the liver and the findings that the treatment with the drug elevated absolute mass and mass proportion of 18:1 at the C-2 position, but not the C-1 position, of PC in the liver together.

Inhibitory effects of peony root extract on the large conductance calcium-activated potassium current essential in production of bursting activity

To elucidate the mechanism of inhibitory action of peony root extract on pentylenetetrazol-induced bursting activity, effects of peony root extract on the iberiotoxin-sensitive large conductance calcium-activated potassium (BKCa) current that plays an essential role in the production of bursting activity were investigated. Peony root extract showed a clear inhibitory effect on the iberiotoxin-sensitive calcium-activated potassium current. Peony root extract also showed clear inhibitory effects on spontaneous bursting activity and BKCa current in the cerebral cortical neurons of the EL mouse, a hereditary epilepsy animal model. These results together with our previous studies, including the protective effect against neuron damage, indicate that peony root extract is a promising herbal drug for inhibition of convulsions.

Induction of tumor-specific cytotoxicity and apoptosis by doxorubicin

Doxorubicin (adriamycin), an anthracycline antibiotic, showed higher cytotoxic activity against human tumor cell lines (oral squamous cell carcinoma HSC-2, HSC-3, submandibular gland carcinoma HSG, promyelocytic leukemia HL-60) than against normal human cells (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF). Doxorubicin activated caspases 3, 8 and 9 in both HSC-2 and HL-60 cells, but induced internucleosomal DNA fragmentation only in HL-60 cells. Western blot analysis showed that doxorubicin did not significantly change the intracellular concentration of Bcl-2, Bax and Bad in HL-60 cells. Real-time PCR analysis showed that HPC cells expressed the highest amount of mdr1 mRNA, followed by HSC-2 > HGF > HSC-3 > HPLF > HSG > HL-60. ESR spectroscopy showed that doxorubicin produced no discernible radical under alkaline conditions (pH 7.4 to 10.5) except at pH 12.5, and it did not scavenge O2-, NO and DPPH radicals. The present study demonstrates that doxorubicin induces the tumor-specific cytotoxicity and some, but not all, apoptosis markers possibly by a radical-independent mechanism, and that mdr1 expression in the tumor cells is not related to the tumor specificity of doxorubicin.

Pro-apoptotic protein glyceraldehyde-3-phosphate dehydrogenase promotes the formation of Lewy body-like inclusions

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) has long been recognized as a classical glycolytic protein; however, previous studies by our group and others have demonstrated that GAPDH is a general mediator initiating one or more apoptotic cascades. Our most recent findings have elucidated that an expression of a pro-apoptotic protein GAPDH is critically regulated at the promoter region of the gene. Apoptotic signals for its subsequent aggregate formation and nuclear translocation are controlled by the respective functional domains harboured within its cDNA component. In this study, coexpression of GAPDH with either wild-type or mutant (A53T) alpha-synuclein and less likely with beta-synuclein in transfected COS-7 cells was found to induce Lewy body-like cytoplasmic inclusions. Unlike its full-length construct, the deleted mutant GAPDH construct (C66) abolished these apoptotic signals, disfavouring the formation of inclusions. The generated inclusions were ubiquitin- and thioflavin S-positive appearing fibrils. Furthermore, GAPDH coimmunoprecipitated with wild-type alpha-synuclein in this paradigm. Importantly, immunohistochemical examinations of post mortem materials from patients with sporadic Parkinson's disease revealed the colocalized profiles immunoreactive against these two proteins in the peripheral zone of Lewy bodies from the affected brain regions (i.e. locus coeruleus). Moreover, a quantitative assessment showed that about 20% of Lewy bodies displayed both antigenicities. These results suggest that pro-apoptotic protein GAPDH may be involved in the Lewy body formation in vivo, probably associated with the apoptotic death pathway.

Disclosure of a pro-apoptotic glyceraldehyde-3-phosphate dehydrogenase promoter: anti-dementia drugs depress its activation in apoptosis

Overexpression and subsequent nuclear accumulation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is involved in neuronal apoptosis induced by several stimuli in which GAPDH antisense oligonucleotides specifically block the increment (2 approximately 3 fold) of GAPDH mRNA contents occurring prior to neuronal death. However, these agents do not affect the basal, constitutive mRNA contents. This suggests that there may be distinct gene regulations for GAPDH mRNA expression. Herein, we cloned two types of promoter regions upstream of this gene; viz., #104 (1.02-kb) and #302 (2.46-kb). These fragments were inserted into the pGL3 luciferase reporter system and transiently transfected into cultured cerebellar neurons undergoing cytosine arabinonucleoside-induced apoptosis. The functional analysis of these constructs revealed that #104, but not #302, increased luciferase activity in response to the apoptotic stimulus. Deletion and replacement mutation analysis of the #104 fragment disclosed the promoter core harbored between the 154-bp and 84-bp domains (3.5-fold activity of the control). Furthermore, anti-dementia drugs (such as Cognex and Aricept) markedly depress the expression of this pro-apoptotic GAPDH promoter activity. Interestingly, immunocytochemical examination of human post-mortem materials from patients with Alzheimer's disease revealed nuclear aggregated GAPDH in neurons of the affected brain regions, implying an association with apoptotic cell death. The current findings indicate that induction of the pro-apoptotic protein GAPDH is genetically regulated at the level of promoter activation, and this protein may be an important molecular target for developing anti-apoptotic therapeutic agents in certain neurological illnesses.

Overexpression of Glyceraldehyde-3-phospahe Dehydrogenase Is Not Involved in 5-Hydroxytryptamine (5-HT)-Induced Necrosis in Cultured Cerebrocortical Neurons

Cerebrocortical cell cultures were prepared from 1-d-old rats. On post-culture day 6, 5-hydroxytryptamine (5-HT) was added to the medium and cells were exposed for another 3 d. 5-HT elicited cytotoxicity in a dose-dependent manner, and the survival rate of neuronal cells was decreased to 64.9+/-5.0% at 0.1 mM concentration. Chromatin staining with Hoechst 33258 and electron microscopy revealed that the 5-HT-induced neuronal death was entirely due to necrosis. Pretreatments with glyceraldehyde-3-phosphate dehydrogenase (GAPDH) antisense oligonucleotide and several classical apoptotic inhibitors did not exhibit neuroprotection in this paradigm. Northern blot analysis showed that the enhancement of GAPDH mRNA levels was undetected during cell death. The present results demonstrate that GAPDH overexpression is not involved in the 5-HT-induced necrotic death pathway.

Molecular mechanism of preventive effect of peony root extract on neuron damage

The molecular mechanism of the protective effects of peony root extract and its component substances on neuron damage induced by the cobalt focus epilepsy model and the EL mouse was investigated. Long-term administration of peony root extract for 30 days prior to metallic cobalt powder application to the cerebral cortex of mice resulted in increased expression of A20, an inhibitor gene of cell death. In the EL mouse, a hereditary epilepsy animal model with vulnerable neurons, increased expression of A20 was observed even without administration of peony root extract. Long-term administration of peony root extract to the EL mouse resulted in a marked increase of expression of A20. These results suggested that an increase in A20 expression is the main molecular mechanism of protective action of peony root extract on neuron damage.

Dosing time-dependent pharmacological effects of anti-metabolites for rat cardiac graft

Antimetabolites such as methotrexete and 6-mercaptopurine have been shown to have circadian variations in their toxicities. However, chronopharmacological profiles of mizoribine (Miz) that is newly synthesized as an anti-metabolic agent for immunosuppression, have not been evaluated. In this study, we examined the dosing time-dependent alterations in the pharmacokinetics and pharmacodynamics of Miz. In addition, chronopharmacology of azathiopurine (Aza) was also evaluated to compare with that of Miz. Initially, Miz (10 and 20 mg/kg) or Aza (20 mg/kg) was orally administered at 8:00 hr or 20:00 hr for 3 weeks to rats. To reveal the dosing time-dependent difference of pharmacokinetics, Miz (20 mg/kg) was orally given at 8:00 hr or 20:00 hr and blood was obtained for 12 hours. Finally, Miz (20 mg/kg) or Aza (20 mg/kg) was administered at 8:00 hr or 20:00 hr to rats with heterotopic allogeneic heart grafts. The Miz group treated at 8:00 hr and Aza group treated at 20:00 hr showed severe myelosuppression compared with their each opposite dosing time. AUC of Miz in the morning trial was twice as high as that in the evening trial. The graft survival durations of the Miz- and Aza-treated groups were significantly longer than those of the respective control groups, but were not affected by dosing time of each agent. These results suggest that the toxicity, but not efficacy of Miz is varied with the dosing time. The chronotoxicological phenomenon of Miz might be, at least in part, explained by the dosing time-dependent difference in serum drug concentrations and apparent clearance.

Trifluoromethyl ketones show culture age-dependent inhibitory effects on low K(+)-induced apoptosis in cerebellar granule neurons

We previously reported that two trifluoromethyl ketones, 3,3,3-trifluoro-1-phenyl-1,2-propanedione (TF1) and 1,1,1-trifluoro-3-phenyl-2-propanone (TF2), have neuroprotective effects against low K(+)-induced apoptosis in cerebellar granule neurons (CGNs) exposed at 12-13 days in vitro (DIV). On the other hand, these compounds showed weak neuroprotective potency against 7 DIV CGNs. It is reported that actinomycin D (Act-D), cycloheximide (CHX), and caspase-3 inhibitors prevent the apoptosis of CGNs induced by K+ deprivation. However, these experiments are generally performed using 7 DIV CGNs. We investigated and compared the antiapoptotic efficacy of these drugs and newly-discovered TF1 and TF2 to protect DIV 7 and 12-13 CGNs from death induced by K+ deprivation. Apoptosis of CGNs induced by K+ withdrawal at 13 DIV was potently inhibited by Act-D and CHX similar to those at 7 DIV. Caspase-3 inhibitors moderately suppressed cell death during low K(+)-induced apoptosis both exposed 7 and 13 DIV. Serine protease inhibitor N-tosyl-L-phenylalanyl chloromethylketone (TPCK) had no effect on K(+)-deprivation-induced apoptosis of CGNs at both 7 and 12 DIV. This study showed that there are different pathways of apoptosis in CGNs depending on the culture age.

Trifluoromethyl ketone-based inhibitors of apoptosis in cerebellar granule neurons

A variety of aromatic trifluoromethyl ketone derivatives has been studied as inhibitors of apoptosis in cerebellar granule neurons (CGNs). Among them, alpha-trifluoromethyl diketone (2) and benzyl trifluoromethyl ketone (11) were found to be apoptosis inhibitors which can prevent a neurodegenerative disease. Compounds 2 and 11 showed neuroprotection effect on low K+-induced apoptosis in CGNs. Furthermore, these compounds effectively suppressed DNA fragmentation accompanied with apoptosis. The neuroprotection mode of 2 and 11 was not related to inhibition of caspase-3.

Antioxidative activity of Allium victorialis L. extracts

Allium victorialis L. (Liliaceae, "Hon-Gyoujya Nin-Niku" in Japanese) was successively extracted with hexane, acetone, methanol and 70% methanol and the extracts were further separated into a total of twenty-five fractions by silica gel and ODS column chromatographies. The biological activities of these four extracts and 25 column fractions were compared. The cytotoxic activity of all extracts and fractions against two oral tumor cell lines was significantly higher than that against normal human gingival fibroblasts, suggesting their tumor-specific action. Three methanol column fractions [M2, M3, M6] and a 70% methanol column fraction [70M6] most effectively reversed the multidrug resistance (MDR) against L5178 mouse T cell lymphoma. The electron spin resonance (ESR) spectroscopy showed that methanol column fractions and 70% methanol extracts produced the highest amount of radical(s) and most efficiently scavenging O2*-, generated by the hypoxanthine-xanthine reaction system, suggesting that the same substances in these fractions display both prooxidant and antioxidant properties. They showed no anti-human immunodeficiency virus (HIV) or anti-Helicobacterpylori activity. These data suggest the medicinal efficacy of Allium victorialis extract.

Effect of glucocorticoid on expression of rat MUC5AC mRNA in rat gastric mucosa in vivo and in vitro

The gastric mucus is an important factor in the gastric mucosal protection from acid, pepsin and various reagents (alcohol, aspirin, etc.). MUC5AC is the mucin secreted from surface mucous cells, and belongs to the gel-forming mucin. We examined the regulation of rat MUC5AC (rMUC5AC) mRNA by glucocorticoid in vivo and in vitro, comparing it with that of pepsinogen (Pg) mRNA. By adrenal gland resection, rMUC5AC and Pg mRNA levels and Pg content in rats significantly decreased to 70%, 46% and 42% of those in the sham operated controls, respectively. With the treatment of hydrocortisone (1, 5 and 50 mg/kg), Pg mRNA level and Pg content in adrenalectomized rats was restored. On the other hand, the rMUC5AC mRNA level exceeded the control with 1 or 5 mg/kg injections of hydrocortisone, but drastically decreased to 18% of sham operation levels with it (50 mg/kg). Similar results were obtained in normal rats with the treatment of hydrocortisone (50 mg/kg). Mucus and DNA content of cultured rat gastric epithelial cells were not affected by hydrocortisone, but rMUC5AC mRNA level was significantly decreased in a dose-dependent manner. From the in vivo and in vitro results, at least a physiological concentration of glucocorticoid was necessary in the expression of rMUC5AC mRNA. However, high dose of hydrocortisone directly suppressed the expression of rMUC5AC mRNA. These results suggested that hydrocortisone might directly cause the suppression and indirectly the enhancement of the mucin biosynthesis.

ONO-1603, a potential antidementia drug, delays age-induced apoptosis and suppresses overexpression of glyceraldehyde-3-phosphate dehydrogenase in cultured central nervous system neurons

Primary cultures of rat cerebral cortical cells and cerebellar granule cells die by an apoptotic mechanism after more than 2 weeks in cultures in the absence of medium change and glucose supplement, a process termed age-induced apoptosis of cultured neurons. Our preliminary study has shown that age-induced apoptosis of cerebellar granule cells is protected by pretreatment with tetrahydroaminoacridine (THA), an antidementia drug. In this study, we systematically compared the neuroprotective effects of THA with those of (S)-1-[N-(4-chlorobenzyl)succinamoyl]pyrrolidine-2-carbaldehyde (ONO-1603), a novel prolyl endopeptidase inhibitor and potential antidementia drug. Both ONO-1603 and THA effectively delay age-induced apoptosis of cerebral and cerebellar neurons, as demonstrated morphologically with toluidine blue and fluorescein diacetate/propidium iodide staining or biochemically by DNA laddering analysis on agarose gels. ONO-1603 is about 300 times more potent than THA, with a maximal protective effect at 0.03 and 10 microM, respectively. ONO-1603 shows a wide protective range of 0.03 to 1 microM in contrast to a narrow effective range of 3 to 10 microM for THA. Moreover, ONO-1603 is nontoxic to neurons, even at the high concentration of 100 microM, whereas THA elicits severe neurotoxicity at a dose of >/=30 microM. Both ONO-1603 and THA robustly suppress overexpression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) mRNA and accumulation of GAPDH protein in a particulate fraction of cultured neurons undergoing age-induced apoptosis. Because we documented that GAPDH overexpression participates in neuronal apoptosis induced by various insults, we conclude that the neuroprotective actions of ONO-1603 and THA appear to be mediated by suppression of this protein overexpression.

Nuclear localization of overexpressed glyceraldehyde-3-phosphate dehydrogenase in cultured cerebellar neurons undergoing apoptosis

We recently reported that overexpression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) is directly involved in cytosine arabinonucleoside (ara-C)- and low K+-induced neuronal death of cultured cerebellar granule cells. The former is entirely due to apoptosis, whereas the latter involves both apoptosis and necrosis. We examined the subcellular distribution of the overexpressed GAPDH occurring during apoptosis by using both subcellular fractionation and immunocytochemistry with a monoclonal antibody directed against this overexpressed protein. When immature cerebellar neurons were exposed to ara-C, an overexpression of GAPDH was observed, primarily in the nuclear fraction. In contrast, low K+ exposure of mature cerebellar neurons induced the overexpression of GAPDH not only in the nuclear fraction but also in the mitochondrial fraction. In both paradigms, no significant change of GAPDH levels occurred in the microsomal and cytosolic fractions. Moreover, pretreatment with GAPDH antisense oligonucleotide or classic apoptotic inhibitors clearly suppressed the accumulation of GAPDH protein in these subcellular loci. This discrete nuclear localization of GAPDH during apoptosis was supported further by immunoelectron microscopy. Quantitative assessment of GAPDH immunogold labeling revealed that a approximately 5-fold increase in the intensity of gold particles was observed within the nucleus of apoptotic cells. Thus, the current results raise the possibility that neuronal apoptosis may be triggered by GAPDH accumulation in the nucleus, resulting in perturbation of nuclear function and ultimate cell death.

Overexpression of glyceraldehyde-3-phosphate dehydrogenase is involved in low K+-induced apoptosis but not necrosis of cultured cerebellar granule cells

We have reported that overexpression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) is involved in age-induced apoptosis of the cultured cerebellar granule cells that grow in a depolarizing concentration (25 mM) of KCI. The present study was undertaken to investigate whether GAPDH overexpression also occurs and participates in apoptosis of the cerebellar granule cells that result from switching the culturing conditions from high (25 mM) to low (5 mM) concentrations of KCl. We found that exposure of granule cells to low potassium (K+) for 24 hr induces not only apoptosis but also necrotic damage. The latter is supported by the morphological observations that a subpopulation of neurons showed cell swelling, extensive cytoplasmic vacuolization, damaged mitochondria, and apparently intact nuclei. Treatments with two antisense but not sense oligodeoxyribonucleotides directed against GAPDH attenuated low K+-induced neuronal death by approximately 50%. Morphological inspection revealed that GAPDH antisense oligonucleotides preferentially blocked low K+-induced apoptosis with little or no effect on necrotic damage. Similar to antisense oligonucleotides, actinomycin-D partially inhibited low K+-induced death of granule cells with a predominant effect on apoptosis. In contrast, cycloheximide almost completely blocked low K+-induced neuronal death and seemed to prevent both apoptotic and necrotic damage. The levels of GAPDH mRNA and protein were markedly increased in a time-dependent manner after low K+ exposure. The overexpression of GAPDH mRNA and protein was completely blocked by cycloheximide, actinomycin-D, and its antisense but not sense oligonucleotides. Taken together, these results lend credence to the view that exposure of cerebellar granule cells to low K+ induces both apoptosis and necrosis and that only the apoptotic component involves overexpression of GAPDH.

Effect of ranitidine on renal clearance of lomefloxacin

OBJECTIVE

To examine the effect of ranitidine on the renal clearance of lomefloxacin.

SETTING

Department of Clinical Pharmacology, Jichi Medical School.

METHODS

Lomefloxacin 200 mg and ranitidine 300 mg or its placebo were given orally in a randomised, double-blind, crossover design. Blood and urine samples were obtained during a 24-h period after dosing.

RESULTS

The area under the plasma concentration-time curve and the elimination half-life of lomefloxacin were significantly increased following coadministration with ranitidine. These effects were caused by significant decreases in total (7.8%) and renal (22%) clearance of lomefloxacin. In contrast, creatinine clearance and urinary excretion of electrolytes were not influenced by ranitidine.

CONCLUSION

As lomefloxacin and ranitidine are excreted in urine by renal tubular secretion, the present results suggest that the renal tubular secretion of lomefloxacin is diminished by ranitidine. As the reduction in lomefloxacin clearance is only marginal, it is probable that the drug interaction observed in this study is not of clinical significance.

ONO-1603, a potential antidementia drug, shows neuroprotective effects and increases m3-muscarinic receptor mRNA levels in differentiating rat cerebellar granule neurons

We have reported that the antidementia drug tetrahydroaminoacridine (THA; 30 microM) is neuroprotective and neurotrophic and selectively increases m3-muscarinic acetylcholine receptor (mAChR) mRNA levels in differentiating cerebellar granule cells. Here, we examined whether novel prolyl endopeptidase inhibitor ONO-1603, a potential antidementia drug, induces similar effects in these cerebellar neurons. Supplement of ONO-1603 (0.03 microM) to cultures grown in 15 mM KCl-containing media was found to markedly promote neuronal survival and neurite outgrowth and enhance [3H]N-methylscopolamine binding to mAChRs. Moreover, ONO-1603 increased the level of m3-mAChR mRNA and stimulated mAChR-mediated phosphoinositide turnover. The common actions of ONO-1603 and THA suggest that these properties could be related to their putative antidementia activities and that this model system may be used to screen for drugs effective in the treatment for Alzheimer's disease.

An antisense oligodeoxynucleotide to glyceraldehyde-3-phosphate dehydrogenase blocks age-induced apoptosis of mature cerebrocortical neurons in culture

We recently reported that the age-induced apoptotic death of cultured cerebellar neurons is correlated with an increased expression of a particulate-bound 38-kDa protein that we identified as glyceraldehyde-3-phosphate dehydrogenase (GAPDH). To determine whether this phenomenon of GAPDH overexpression occurs in other cell types, we selected primary cultures of cerebrocortical cells for testing, because under normal culture conditions, cortical neurons die progressively after 15 days in vitro. As with cerebellar neurons, this age-induced neuronal death involves ultrastructural changes and internucleosomal DNA fragmentation characteristic of apoptosis and is effectively prevented by actinomycin-D and cycloheximide. Moreover, a GAPDH antisense oligodeoxyribonucleotide arrested this cortical neuronal death for about 4 to 5 days and thus was more effective than cycloheximide. By contrast, its corresponding sense oligonucleotide had no effect. Additionally, the age-induced apoptosis of cortical neuronal cultures is effectively protected by aurintricarboxylic acid and tetrahy-droaminoacridine (an antidementia drug). Before cell death, GAPDH mRNA levels increased by about 2-fold and the increase was blocked by the above-mentioned neuroprotective agents and the GAPDH antisense, but not sense, oligonucleotide. The effects of antisense oligonucleotide are more robust in the present case than those found with cerebellar neurons, and they indicate a significant, though at present not defined, role of GAPDH in the apoptotic process occurring in these two types of neurons.

Clinical pharmacology of multiple-dose losartan, an angiotensin II receptor antagonist, in patients with essential hypertension

The pharmacokinetic and pharmacodynamic alterations of multiple doses of losartan, an angiotensin II receptor antagonist, were examined in nine patients with essential hypertension. Participants were given placebo once daily for the first 7 days (from day -7 to day -1), and then 50 mg of losartan for the next 9 days (from day 1 to day 9). The 24-hour blood pressure was measured on days -1, 1, and 7 and blood samples for measurement of losartan and its active metabolite, E-3174, were obtained on days 1 and 7. Plasma concentrations of uric acid and plasma clearance were determined before and during treatment with losartan, and at the end of the study. Pharmacokinetic parameters after the seventh dose, including maximum plasma concentration (Cmax) and time to Cmax (tmax) of losartan and E-3174, did not differ significantly from those after the first dose. The blood pressure lowering effect of losartan, however, was significantly greater after the seventh dose than after the first dose. Plasma uric acid decreased and its plasma clearance (ClUA) increased significantly during repeated administration with losartan. These values returned to pretreatment levels after the end of treatment. These results suggest that although the pharmacokinetic profiles of losartan and E-3174 do not change during repeated administration, the blood pressure lowering effect in hypertensive patients is greater after multiple doses than after a single dose.

Evidence that glyceraldehyde-3-phosphate dehydrogenase is involved in age-induced apoptosis in mature cerebellar neurons in culture

Under typical culture conditions, cerebellar granule cells die abruptly after 17 days in vitro. This burst of neuronal death involves ultrastructural changes and internucleosomal DNA fragmentations characteristic of apoptosis and is effectively arrested by pretreatment with actinomycin-D and cycloheximide. The level of a 38-kDa protein in the particulate fraction is markedly increased during age-induced cell death and by pretreatment with NMDA, which potentiates this cell death. Conversely, the age-induced increment of the 38-kDa particulate protein is suppressed by actinomycin-D and cycloheximide. N-terminal microsequencing of the 38-kDa protein revealed sequence identity with glyceraldehyde-3-phosphate dehydrogenase (GAPDH). A GAPDH antisense oligodeoxyribonucleotide blocks age-induced expression of the particulate 38-kDa protein and effectively inhibits neuronal apoptosis. In contrast, the corresponding sense oligonucleotide of GAPDH was completely ineffective in preventing the age-induced neuronal death and the 38-kDa protein overexpression. Moreover, the age-induced expression of the 38-kDa protein is preceded by a pronounced increase in the GAPDH mRNA level, which is abolished by actinomycin-D, cycloheximide, or the GAPDH antisense, but not sense, oligonucleotide. Thus, our results suggest that overexpression of GAPDH in the particulate fraction has a direct role in age-induced apoptosis of cerebellar neurons.

Lack of diurnal variation in glomerular filtration rates in the elderly

The present study was undertaken to examine the effect of age on diurnal variation in glomerular filtration rate (GFR). The GFR, as estimated by creatinine clearance (Clcr), was determined during a 24-hour period in 10 younger (mean +/- SD age 42 +/- 9 years) and 10 older (mean age 75 +/- 4 years) patients with hypertension. Significant diurnal variations in Clcr were observed in the younger patients, with a peak during the day and trough during the night. Such were not observed in the older patients, however. These results suggest that diurnal variation in GFR is affected by age. Chronopharmacologic profiles of drugs, which are mainly excreted in urine by glomerular filtration, might be altered in these patients.

Glyceraldehyde-3-phosphate dehydrogenase is over-expressed during apoptotic death of neuronal cultures and is recognized by a monoclonal antibody against amyloid plaques from Alzheimer's brain

The age-induced apoptotic death of cerebellar neurons in culture is associated with over-expression of a 38-kDa particulate protein identified as glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Both the age-induced apoptosis and the 38-kDa protein overexpression were effectively suppressed by the presence of tetrahydroaminoacridine, an antidementia drug, or aurintricarboxylic acid. This over-expressed 38-kDa protein and purified GAPDH were found to react with a monoclonal antibody (mAb), Am-3, which was raised against amyloid plaques from Alzheimer's brain, but not with mAb, AmT-1, which was produced using synthetic amyloid beta peptide. These results raise the possibility that GAPDH is also involved in the neurodegeneration during the development of Alzheimer's disease.

Chronopharmacology of enalapril in hypertensive patients

The pharmacokinetics and pharmacodynamics of enalapril, an angiotensin converting enzyme inhibitor, are reported to vary with the time of administration. The present study was undertaken to examine whether the effect of enalapril on plasma bradykinin (BK), substance P and prostaglandin E2 (PGE2), which are likely to be involved in the mechanism of enalapril-induced cough, might also be affected by its time of administration. Enalapril 5 mg or placebo was given orally at 10:00 h (day trial) or 22:00 h (night trial) to 12 patients with essential hypertension. Serum concentrations of total drug (enalapril + enalaprilat, its active metabolite) during the day and night trials did not differ significantly at any time. However, serum enalaprilat tended to be higher and its maximum concentration greater in the day trial than in the night trial. Blood pressure 24 h after administration of enalapril was reduced at 22:00 h, but not at 10:00 h. Plasma BK tended to increase following enalapril administration at 10:00 h, but not at 22:00 h. Remarkable increases in plasma BK were observed in two patients in the day trial and one of them also complained of cough. However, no such increase in plasma BK or subsequent adverse effect were recorded in the night trial. Plasma substance P and PGE2 did not change significantly following enalapril administration either in the day or night trial. The results suggest that the response of BK to enalapril is affected by the time of administration. In patients who complain of cough during treatment with enalapril during the daytime, this adverse effect might be diminished or eliminated by a switch to night-time administration.

Effect of losartan, an angiotensin II receptor antagonist, on response of cortisol and aldosterone to adrenocorticotrophic hormone

Many imidazole derivatives are shown to inhibit adrenal steroid biosynthesis. The present study was undertaken to examine an effect of another imidazole derivative, losartan (an angiotensin II receptor antagonist), on responses of cortisol and aldosterone to adrenocorticotrophic hormone (ACTH). Nine patients with essential hypertension were given placebo orally for 7 days and 50 mg of losartan for the next 9 days. Response of serum cortisol and plasma aldosterone to intramuscular ACTH injection were determined before and at the end of the treatment with losartan. Serum cortisol and plasma aldosterone significantly increased after ACTH injection in both periods of treatment (placebo and losartan). The increments in these parameters during treatment with losartan were not significantly different from those during treatment with placebo. These results suggest that the inhibitory effect of losartan on adrenal steroid biosynthesis is negligible.

Recombinant human growth hormone and protein metabolism of burned rats and esophagectomized patients

The effects of recombinant human growth hormone (rhGH) on protein metabolism were investigated. In the experimental study, 31 male Sprague-Dawley rats were divided into two groups. One group received 200 mU/day of rhGH for 3 consecutive days, before and after being burned (GH group). The other group received no rhGH as a control. Cumulative nitrogen balance after being burned was significantly higher in the GH group, and the rates of whole-body protein turnover, synthesis, and breakdown were significantly higher in the GH group. An increase of synthesis greater than that of breakdown resulted in an improved nitrogen balance in the GH group. Protein content of the liver and the gastrocnemius muscle were also significantly greater in the GH group. In the clinical study, 13 patients receiving esophagectomy for esophageal cancer were studied. Six of them received 24 U/day of rhGH for 5 consecutive postoperative days (GH group). Cumulative nitrogen balance on postoperative days was significantly higher in the GH group than in the control group. On the 3rd postoperative day, the rate of whole-body protein synthesis was significantly greater in the GH group; those of turnover and breakdown also increased in the GH group. The arteriovenous difference of amino acid composition revealed that uptake of branched-chain amino acids into the leg muscles was significantly elevated and that release of phenylalanine and tyrosine from the muscles was significantly reduced in the GH group. Hepatic function was not affected by the administration of rhGH, and rhGH inhibited the rise of blood urea nitrogen and total bilirubin after esophagectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration time-dependent change in the effect of spironolactone in aged rats

We have previously demonstrated that the natriuretic effect of spironolactone, a competitive antagonist of mineralocorticoid, varies with its administration time in young rats. The present study was undertaken to examine the influence of aging on chronopharmacological profiles of the agent. Spironolactone (10 and 50 mg/kg) was given orally at 12 am or 12 pm in young (12 weeks old) and aged (28 months old) Wistar rats. The 8-hour urine was collected after each administration, and the urinary sodium excretion was determined. The urinary sodium excretion increased dose-dependently following spironolactone in the young and aged groups of rats. The increments in this parameter in the 12 pm trial were significantly greater than those of the 12 am trial in the young rats. However, such an administration time-dependent difference in the effect of spironolactone was diminished and did not reach statistical significance in the aged animals. These results suggest that the mode of the administration time-dependent change in the effect of spironolactone is altered with age.

Tetrahydroaminoacridine increases m3-, but not m2-, muscarinic acetylcholine receptor mRNA levels in differentiating cerebellar granule cells

We used Northern blot hybridization to determine whether 9-amino-1,2,3,4-tetrahydroacridine (THA), a potential antidementia drug, selectively altered the levels of muscarinic acetylcholine receptor (mAChR) mRNA in differentiating cerebellar granule cells. Granule cells were cultured for 8 days in media containing 15 mM K+, 25 mM K+ or 15 mM K+ plus 30 microM THA. High K+ markedly increased the levels of m2- and m3-mAChR mRNA in the surviving cells. In contrast, THA increased the levels of m3-mAChR mRNA, but had little or no effect on m2-mAChR mRNA levels. These results suggest that THA selectively up-regulates the synthesis of m3-mAChR mRNA.

Influence of lisinopril on urinary electrolytes excretion after furosemide in healthy subjects

It has been reported that the urinary excretions of chloride (Cl), potassium (K), and magnesium (Mg), but not sodium (Na), after furosemide, a loop diuretic, were decreased by pretreatment with lisinopril, an ACE inhibitor in hypertensive subjects. The electrolytes disturbance induced by furosemide might be ameliorated by lisinopril. The present study re-examines this potential drug interaction in healthy subjects. Lisinopril (20 mg) or its matching placebo was given orally using a double-blind, crossover design. Four hours after lisinopril administration, furosemide (20 mg) was injected intravenously and urine was collected during the following intervals: 0-0.5, 0.5-1, 1-1.5, 1.5-2, 2-3, 3-4, and 4-6 hours. Blood samples for plasma furosemide concentration were obtained at 0.5, 1, 1.5, 2, 3, 4, and 6 hours after the agent. There were no significant differences between the two trials in plasma concentrations of furosemide or urinary excretions of the agent. Urine volume and urinary excretions of electrolytes (Na, Cl, K, and Mg) after the furosemide with lisinopril administration were not significantly different from those of placebo at any observation period. These results suggest that the urinary excretions of electrolytes after furosemide administration are not influenced by pretreatment with lisinopril.

Autoradiographic demonstration of an increase in muscarinic cholinergic receptors in cerebellar granule cells treated with tetrahydroaminoacridine

The neurotrophic and neurosurviving effects of 9-amino-1,2,3,4-tetrahydroacridine (THA), a putative antidementia agent, were studied in cultured granule cells using biochemical and morphological methods. The addition of 30 microM THA to cultures grown in 15 mM K(+)-containing media markedly increased cell survival and enhanced [3H]N-methylscopolamine binding to muscarinic cholinergic receptors (mAChRs). Furthermore, receptor autoradiographic studies revealed that neuronal cells were labelled over both cell bodies and fibers by the [3H]receptor ligand. These observations provide direct evidence that THA promotes the expression of mAChR binding sites in differentiating cerebellar granule cells.

Repeated alcohol intake changes circadian rhythm of ambulatory blood pressure

The blood pressure of 7 clinically healthy volunteering social drinkers was studied while they consumed, with a crossover design for 5 days, either 40 g of alcohol by day or fruit juice, with the two spans on alcohol and juice being separated by a one-week washout. Whereas the rhythm-adjusted mean was not changed, a clear statistically significant increase in the circadian double amplitude was found. The study provides a model for a rapidly achieved circadian amplitude hypertension which may precede an elevation of the overall blood pressure mean in the natural course of the disease.

Tetrahydroaminoacridine is neurotrophic and promotes the expression of muscarinic receptor-coupled phosphoinositide turnover in differentiating cerebellar granule cells

We have investigated whether 9-amino-1,2,3,4-tetrahydroacridine (THA), a drug with potential antidementia activity, has a trophic action on differentiating cerebellar granule cells by using the method of [3H]inositol incorporation into inositol-containing phospholipid. Addition of THA (30-50 microM) prevented the extensive neuronal degeneration which occurred in the growth medium containing "low" K+ (15 mM). These effects were similar to the neuroprotective action caused by the presence of 100 microM N-methyl-D-aspartate (NMDA). Neurotrophic effects of THA and NMDA on cells grown in low K+ were also demonstrated by direct microscopic examination of cellular morphology. Measurement of phosphoinositide (PI) response in the rescued cells indicated that NMDA modestly promoted the PI response to carbachol and norepinephrine but markedly stimulated the activity induced by glutamate. In contrast, although THA had little or no influence on the maturation of the norepinephrine- and glutamate-induced PI response, it selectively enhanced the activity stimulated by carbachol. Furthermore, the THA treatment drastically increased the Vmax value of carbachol-induced PI turnover with no significant alteration in the EC50 value. Scatchard analysis of the binding of N-[3H]methylscopolamine to intact granule cells indicated a selective increase in the maximum binding value in cells grown in THA-supplementing medium. These observations suggest that THA seems to selectively up-regulate muscarinic cholinergic receptors.