Effects of beta 1- and beta 1 + beta 2-antagonists on training-induced myocardial hypertrophy and enzyme adaptation

The effects of beta 1- and beta 1 + beta 2-antagonists on the myocardial adaptation to exercise training were investigated in male Sprague-Dawley rats randomly divided into trained (treadmill, 1 hr/day, 5 days/week for 10 weeks at 27 m/min, 15% grade) without drug (TC), sedentary without drug (SC), trained treated with atenolol (TA) (10 mg/kg body wt, i.p.), trained treated with propranolol (TP, 30 mg/kg body wt, i.p.), and sedentary propranolol. Doses of both beta-antagonists were titrated to decrease the exercise heart rate by 25% compared to the controls. The heart weight and heart/body weight ratio were significantly greater in TC (1.28 +/- 0.07 g (P less than 0.01); 296 +/- 12 mg/100 g body wt (P less than 0.05) respectively) than in SC (1.09 +/- 0.04 g and 268 +/- 11 mg/100 g body wt), or in TP and TA. Myocardial mitochondrial protein was unchanged by training or beta-blockade. Citrate synthase and beta-hydroxyacyl CoA dehydrogenase activities were not altered. Carnitine palmitoyltransferase activity was increased in SP compared to SC. Training increased hexokinase activity only in TC (5.22 +/- 0.12 vs 4.26 +/- 0.23 mumol/min/g wet wt, P less than 0.01). Lactate dehydrogenase activity increased significantly (P less than 0.01) in both TC (383 +/- 14 mumol/min/g wet wt) and TA (372 +/- 14 mumol/min/g wet wt) compared to SC (276 +/- 14 mumol/min/g wet wt), but not in TP versus SP. These data indicate that (1) beta-adrenergic blockade prevents training-induced cardiac hypertrophy; (2) beta-antagonists have little effect on the myocardial oxidative capacity; and (3) while the training induction of myocardial hexokinase is inhibited by both beta 1- and beta 1 + beta 2-antagonists, myocardium may increase its ability to utilize lactate during exercise with training despite beta 1-blockade.     

Tannic acid mitigates cisplatin-induced nephrotoxicity in mice

Cisplatin (CP) is a well-known chemotherapeutic drug that displays dose-limiting nephrotoxicity. In this study, tannic acid (TA), a naturally occurring plant polyphenol, was evaluated for its antioxidant and antigenotoxicity potential against the CP-induced renal oxidative stress and genotoxicity in Swiss albino mice. The mice were given a prophylactic treatment of TA orally at a dose of 40 and 80 mg/kg body weight (b wt) for 7 consecutive days before the administration of a single intraperitoneal (i.p.) injection of CP at 7 mg/kg b wt. The modulatory effects of TA on CP-induced nephrotoxicity and genotoxicity were investigated by assaying oxidative stress biomarkers, serum kidney toxicity markers, DNA fragmentation, alkaline unwinding, micronuclei assay, and by histopathological examination of kidney architecture. CP administration altered the antioxidant levels, enhanced lipid peroxidation, induced DNA strand breaks, and altered the levels of micronuclei among polychromatic erythrocytes (PCEs) significantly (p < 0.001). Pretreatment of TA in mice showed significant (p < 0.001) recovery in antioxidant status, viz., reduced glutathione content and its dependent enzymes, quinone reductase and γ-glutamyl transpeptidase. TA significantly (p < 0.001) reinstated the normal serum levels of blood urea nitrogen (BUN) and creatinine. TA showed strongly inhibited (p < 0.001) micronuclei induction, DNA strand breaks, and DNA fragmentation. Thus, TA as a phytochemical protects kidneys through its antigenotoxic activity and antioxidant potential.     

Mutagenic and antimutagenic assessment of methanol leaf extract of Myristica fragrans (Houtt.) using in vitro and in vivo genetic assays

The role of diets in causing cancers necessitates the ongoing search for natural antimutagens of promising anticancer therapeutics. This study determined the potential anticancer efficacy of the leaf extract of Myristica fragrans (Houtt.). Methanol leaf extract of M. fragrans (Houtt.) alone was screened for mutagenicity in the bacterial reverse mutation (Ames) test, using the Salmonella typhimurium TA100 strain, the Allium cepa, and the mouse in vivo bone marrow micronucleus tests. The antimutagenicity of this extract against benzo[a]pyrene- and cyclophosphamide-induced mutations was evaluated. An antioxidant test on the extract was performed with 2,2-diphenyl-1-picrylhydrazyl, using butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) as the standards, whereas its phytochemicals were elucidated by following the gas chromatography/mass spectrometry protocol. In S. typhimurium (TA100), the mutagenicity ratio at 200,500 and 1,000 μg/well was >2. Cell division in the A. cepa root tips and mouse bone marrow was significantly (P?≤?0.05) inhibited at 2,000 and 4,000?mg/kg, whereas the observed chromosomal aberrations and micronucleated polychromatic erythrocytes were non-dose-related and were insignificantly (P?≥?0.05) different from the negative control. Inhibition of benzo[a]pyrene- and cyclophosphamide-induced mutagenicity by this extract was above 40%. Half-maximal inhibitory concentration of the extract in the antioxidant test was lower than that of BHA and BHT. Phytochemical compounds, possessing antioxidant activity, may be responsible for the observed effects, suggesting a strong antimutagenic activity of the MeOH leaf extract of M. fragrans, a necessary characteristic of a promising anticancer agent.     

Anti-inflammatory, analgesic and anti-pyretic activities of a new anti-inflammatory compound, 2-[4-(3-methyl-2-butenyl)phenyl] propionic acid (TA), in experimental animals

Anti-inflammatory, analgesic and anti-pyretic activities of orally administered TA were investigated in experimental animals. Against acetic acid-induced vascular permeability in mice, carrageenin-induced hind paw edema in rats and ultra-violet ray-induced erythema in guinea pigs, TA produced a dose related inhibition at doses of 40-160 mg/kg, 10-40 mg/kg and 10-40 mg/kg, respectively. TA produced no inhibition against histamine-induced vascular permeability even at a dose of 200 mg/kg in rats. Cotton pellet-induced granuloma and adjuvant-induced arthritis in rats were significantly inhibited by repeated administration of TA at a dose of 50 mg/kg/day for 6 days and 25 mg/kg/day for 6 days, respectively. TA showed a dose related analgesic effect at a dose of 50-200 mg/kg in acetic acid writhing, Randall-Selitto and adjuvant arthritic pain methods. A high dose of TA was needed to produce an analgesic effect in the pressure method using mice. TA produced an anti-pyretic effect against the pyrexia induced by yeast in rats. On the other hand, TA showed no effect against normal body temperature in rats. These results suggest that anti-inflammatory, analgesic and anti-pyretic activities of TA are generally a little weaker than those of ibuprofen, and the mode of action of TA is similar to that of a typical acidic non-steroidal anti-inflammatory drug such as ibuprofen, indomethacin or phenylbutazone. The ulcerogenic activity of TA was about 2 and 4 times weaker than that of ibuprofen in rats and mice, respectively. TA showed a protective effect against gastric necrosis induced by HCl.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of the cytotoxicity, mutagenicity and antimutagenicity of emerging edible plants.

This study evaluates the toxic, mutagenic and antimutagenic effects of emerging edible plants that are consumed as new leafy vegetables in Taiwan. Among eight plant extracts, only the extracts of Sol (Solanum nigrum L.) showed cytotoxicity to Salmonella typhimurium TA100 in the absence of S9 mix. The toxicity of extracts from different parts of the Sol plant, such as leaf and stem, immature fruit and mature fruit, towards S. typhimurium TA100 and human lymphocytes was also assayed. The immature fruit extracts of Sol exhibited strong cytotoxicity with dose dependence and induced significant DNA damage in human lymphocytes based on the comet assay. However, no mutagenicity was found in eight plant extracts to TA98 or TA100 either with or without the S9 mixture. Sol and Sec [Sechium edule (Jacq.) Swartz] extracts showed the strongest inhibitory effect towards the mutagenicity of 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ) in S. typhimurium TA98 and TA100; the ID(50) was less then 1 mg/plate. Cra [Crassocephalum creidioides (Benth.) S. Moore] extracts also expressed moderate antimutagenic activities towards IQ and benzo[a]pyrene (B[a]P) either in TA98 or in TA100; the ID(50) was 1.63-2.41 mg/plate. The extracts from Bas (Basella alba L.), Bou (Boussingaultia gracilis Miers var. pseudobaselloides Bailey), Cen (Centella asiatica L. Urban), Cor (Corchorus olitorius L.) and Por (Portulaca oleracea L.) showed weak to moderate inhibition of mutagenicity of IQ. However, the potential antimutagenicity of these plant extracts towards B[a]P was weaker than that towards IQ. For a direct mutagen, 4-nitroquinoline-N-oxide (NQNO), only the Sol extracts showed strong inhibitory effects in the TA100 system. The antimutagenic activity of water extracts of Sec was partly reduced by heating at 100 degrees C for 20 min. The heat-stable antimutagens in Sec extracts could be produced in the plant extract preparation process. Fractions with molecular weights above 30,000 showed the strongest antimutagenicity and peroxidase activity in all the fractions of the Sec extracts.     

Antimutagenic and anti-oxidant activities of the non-steroidal anti-inflammatory drug celecoxib

1. Tumors arise and progress through the accumulation of serial genetic changes, including successive mutations, which involve activation of proto-oncogenes and inactivation of tumour suppressor genes, leading to the uncontrolled proliferation of progeny cells. The human body is continuously and unavoidably exposed to structurally diverse chemicals with established carcinogenic activity in animal models and/or mutagenic activity in short-term tests. 2. Celecoxib, a non-steroidal anti-inflammatory drug that specifically inhibits the enzyme cyclo-oxygenase-2, has been reported to be effective against certain types of cancers. The in vitro anti-oxidant and antimutagenic activities of the celecoxib were investigated in the present study using standard procedures. 3. The antimutagenic activity of celecoxib was determined using histidine mutant Salmonella typhimurium strains TA98, TA100, TA102 and TA1535 against directly acting mutagens (sodium azide (NaN3), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitro-o-phenylenediamine (NPDA) and doxorubicin) and mutagens needing activation (2-acetamidofluorene (2-AF) and 7,12-dimethylbenz [a] anthracene (DMBA)). 4. Celecoxib inhibited NaN3-, MNNG- and NPDA-induced mutations of TA100. The antimutagenicity of celecoxib (0.2 mg/plate) against the NaN3-induced mutation of TA1535 was 39.8% (P < 0.001). The MNNG-induced mutation of TA1535 was also inhibited by 0.3 mg/plate celecoxib (46.0%; P < 0.05). At concentrations of 0.2 mg/plate, celecoxib significantly inhibited NPDA- and doxorubicin-induced mutations of TA98 by 52.5 and 58.0%, respectively (P < 0.001 and P < 0.05, respectively). 5. The antimutagenic activity of 0.3 mg/plate celecoxib against 2-AF- and DMBA-induced mutations of TA98 was 81.76 and 98.1%, respectively (P < 0.001). 6. The anti-oxidant activity of celecoxib was determined by the inhibition of lipid peroxidation and superoxide and hydroxyl radical-scavenging activities. 7. The IC50 values of celecoxib for hydroxyl radical-scavenging and the inhibition of lipid peroxidation were 1.97 +/- 0.06 and 1.99 +/- 0.05 micromol/mL, respectively. Celecoxib had no superoxide radical scavenging-activity up to a concentration of 2.6 micromol/mL. 8. The in vitro antimutagenic and anti-oxidant activities of celecoxib indicate its possible therapeutic use as a cancer chemopreventive agent.     

Non-coplanar 2,2′,3,3′,4,4′,5,5′,6,6′-decachlorobiphenyl (PCB 209) did not induce cytochrome P450 enzyme activities in primary cultured rat hepatocytes,was not genotoxic,and did not exhibit endocrine-modulating activities

2,2′,3,3′,4,4′,5,5′,6,6′-Decachlorobiphenyl (PCB 209) is a fully chlorinated, non-coplanar biphenyl. To demonstrate that PCB 209 is not likely to exhibit human health hazards common to coplanar PCBs it was tested for cytochrome P450 (P450) enzyme induction potentials, genetic toxicity, and endocrine-modulating activity. PCB 209 (dose from 0.005 to 5000 ng/mL) did not significantly induce P450 CYP1A, 2A, 2B, 3A, or 4A enzyme activities in primary cultured rat hepatocytes. In contrast, Aroclor 1260, a PCB mixture that contains approximately 60% chlorine by weight, showed significant induction of P450 CYP1A, 2A, 2B, and 3A within the same dose range. PCB 209 (dose from 100 to 5000 μg/plate) was negative in the bacterial mutagenicity (Ames) test in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537 or in Eschericia coli strain WP2uvrA. PCB 209 (dose from 25 to 150 μg/mL) was also negative for forward mutations at the thymidine kinase (TK^+/−) locus of L5178Y mouse lymphoma cells. The Ames and the mouse lymphoma assays were both conducted in the absence and presence of rat liver S9 fraction. PCB 209 (dose from 500 to 2000 mg/kg by single dose oral gavage) did not induce an increase in the frequency of micronuclei in polychromatic erythrocytes in mouse bone marrow in vivo. PCB 209 did not induce estrogenic effects when administered by gavage to ovariectomized adult female rats at 500 and 1000 mg/kg for 4 days, nor did it produce alterations consistent with endocrine-modulating activity in adult intact male rats when administered by gavage at 500 and 1000 mg/kg for 15 consecutive days.     

Antimutagenic and anticlastogenic effects of Turkish Black Tea on TA98 and TA100 strains of Salmonella typhimurium (in vitro) and mice (in vivo)

Context: Black tea has been reported to have significant antimutagenic and anticarcinogenic properties associated with its polyphenols theaflavins (TF) and thearubigins (TR). Similarly, Turkish black tea (TBT) also contains a considerable amount of TF and TR.

Objective: This study investigated the mutagenic, antimutagenic and anticlastogenic properties of TBT.

Materials and methods: The mutagenic and antimutagenic effects of TBT (10 to 40000?μg/plate) were investigated in vitro on Salmonella strains TA98 and TA100 with and without S9 fraction. Anticlastogenic effect was studied at concentrations of 300–1200?mg/kg TBT extract by chromosomal aberrations (CA) assay from bone marrow of mice.

Results: The results of this study did not reveal any mutagenic properties of TBT. On the contrary, TBT extract exhibited antimutagenic activity at >1000?μg/plate concentrations in TA98 strain with and without S9 activation (40% inhibition with S9 and 27% without S9). In TA100 strain, the antimutagenic activity was observed at?>20,000?μg/plate TBT extracts without S9 activation (28% inhibition) and at >1000?μg/plate with S9 activation (59% inhibition). A significant decrease in the percentage of aberrant cells (12.33%?±?1.27) was observed in dimethylbenz(a)anthracene (DMBA) plus highest concentration (1200?mg/kg) of TBT extract-treated group when compared to only DMBA-treated group (17.00%?±?2.28).

Discussion and conclusion: Results indicated that TBT can be considered as genotoxically safe, because it did not exert any mutagenic and clastogenic effects. As a result, TBT exhibited antimutagenic effects more apparently after metabolic activation in bacterial test system and had an anticlastogenic effect in mice.     

Cytochrome P4502E1 induction increases thioacetamide liver injury in diet-restricted rats.

Earlier studies have shown highly exaggerated mechanism-based liver injury of thioacetamide (TA) in rats following moderate diet restriction (DR) and in diabetes. The objective of the present study was to investigate the mechanism of higher liver injury of TA in DR rats. Since both DR and diabetes induce CYP2E1, we hypothesized that hepatic CYP2E1 plays a major role in the bioactivation-based liver injury of TA. When male Sprague-Dawley rats (250-275 g) were maintained on diet restriction (DR, 35% of ad libitum fed rats, 21 days) the total hepatic microsomal cytochrome P450 (CYP450) was increased 2-fold along with a 4.6-fold increase in CYP2E1 protein, which corresponded with a 3-fold increase in CYP2E1 activity as measured by chlorzoxazone hydroxylation. To further test the involvement of CYP2E1, 24 and 18 h after pretreatment with pyridine (PYR) and isoniazid (INZ), specific inducers of CYP2E1, male Sprague-Dawley rats received a single administration of 50 mg of TA/kg (i.p.). TA liver injury was >2.5- and >3-fold higher at 24 h in PYR + TA and INZ + TA groups, respectively, compared with the rats receiving TA alone. Pyridine pretreatment resulted in significantly increased total CYP450 content accompanied by a 2.2-fold increase in CYP2E1 protein and 2-fold increase in enzyme activity concordant with increased liver injury of TA, suggesting mechanism-based bioactivation of TA by CYP2E1. Hepatic injury of TA in DR rats pretreated with diallyl sulfide (DAS), a well known irreversible in vivo inhibitor of CYP2E1, was significantly decreased (60%) at 24 h. CCl(4) (4 ml/kg i.p.), a known substrate of CYP2E1, caused lower liver injury and higher animal survival confirming inhibition of CYP2E1 by DAS pretreatment. The role of flavin-containing monooxygenase (FMO) in TA bioactivation implicated by previous in vitro studies, and consequent increased TA-induced liver injury in DR rats was tested in vivo with a relatively selective inhibitor of FMO, indole-3-carbinol, and then treated with 50 mg of TA/kg. FMO activity and alanine aminotransferase levels measured at different time points revealed that TA liver injury was not decreased although FMO activity was significantly decreased, suggesting that hepatic FMO is unlikely to bioactivate TA. These findings suggest induction of CYP2E1 as the primary mechanism of increased bioactivation-based liver injury of TA in DR rats.     

兔眼后Tenon囊下注射曲安奈德后眼内药物浓度

目的经兔眼后Tenon囊下注射曲安奈德后,分析其在视网膜组织及玻璃体腔中的药物浓度。方法选取健康的成年家兔15只,右眼为实验组,左眼为空白对照组。实验组后Tenon囊下注射TA 40mg(约0.2mL),分别在注药后1、3、7、14、28d随机处死3只,取视网膜和玻璃体样本,注药前和处死前都检查眼前节和眼底、测眼压。采用高效液相色谱法测TA的浓度,并进行统计学分析。结果线性回归方程:视网膜Y=0.604X+0.0691,(R2=0.9997,P<0.05);玻璃体Y=0.6258X+0.0372,(R2=0.9998,P<0.05);给药后第1天视网膜中TA的浓度为(1.555±0.654)μg/g,玻璃体腔内TA的浓度为(0.729±0.375)μg/mL,第3天药物浓度均达到最大值,视网膜中TA的浓度为(11.850±4.427)μg/g、玻璃体腔内TA的浓度为(1.621±0.539)μg/mL,以后逐渐下降。实验期间,所有家兔均未见手术及药物所致的并发症。结论兔眼后Tenon囊下注射TA40mg,药物能在视网膜和玻璃体腔中达到较高浓度并维持一定时间。     

Mutagenicity and clastogenicity evaluation of tacrine by Ames and micronucleus assays

Tacrine was evaluated for its mutagenic and clastogenic activities using the Ames bacterial reverse-mutation assay and the rodent bone marrow micronucleus assay. Tacrine was tested for mutagenic potential at six different concentrations, with 1,250 μg/plate as the highest concentration, followed by five lower concentrations with 2-fold spacing. In clastogenic evaluation, tacrine was administered orally to Wistar rats for 2 days at 5, 10, and 20?mg/kg body weights to assess micronucleus induction in bone marrow erythrocytes. In the Ames assay, tacrine showed nonmutagenicity in four tester strains of Salmonella typhimurium viz. TA98, TA100, TA102, and TA1535, but it was found to be mutagenic in the TA1537 tester strain, both in the presence and absence of a metabolic activation system. Tacrine was found to be nonclastogenic on bone marrow cells of rats at all doses tested and was found to be mutagenic in only the TA1537 strain of Salmonella.     

Lack of in vivo clastogenic activity of grape seed and grape skin extracts in a mouse micronucleus assay.

Meganatural brand grape seed extract (GSE) and grape skin extract (GSKE), containing proanthocyanidin polyphenolic compounds, are intended for use in food as functional ingredients exhibiting antioxidant activity. Proanthocyanidins, as well as the minor constituent phenolic compounds in GSE and GSKE, are present naturally in many foods such as fruits, vegetables, chocolate, tea, etc., and on average people consume 460-1000 mg/day of these combined substances. While some polyphenolic compounds, tested individually, have demonstrated antitumorigenic or antipromotional activity, at least one minor component of GSE and GSKE, quercitin, has exhibited positive activity in Salmonella and other in vitro mutagenicity assays. As part of a program to investigate the safety of GSE and GSKE, these products were tested for in vivo clastogenic activity and/or disruption of the mitotic apparatus by detecting micronuclei in polychromatic erythrocyte (PCE) cells in Crl:CD-1(ICR) BR mouse bone marrow. The appropriate test article was dissolved in 0.5% carboxymethylcellulose and dosed by oral gavage to five males/test article/dose level/harvest time point. Animals were dosed at 500, 1000 and 2000 mg/kg. Five animals dosed with either test article at 500, 1000 and 2000 mg/kg dose levels and five animals dosed with the cyclophosphamide (80 mg/kg) positive control were euthanized approximately 24 h after dosing for extraction of bone marrow. Five animals dosed with either test article at the 2000 mg/kg dose level and five animals dosed with the vehicle control article were euthanized approximately 24 and 48 h after dosing for extraction of bone marrow. At least 2000 PCEs per animal were analyzed for frequency of micronuclei. Cytotoxicity was assessed by scoring the number of PCEs and normochromatic erythrocytes (NCEs) in at least the first 500 erythrocytes for each animal. For both GSE and GSKE, no statistically significant increase in micronucleated PCEs was observed at any dose level or harvest time point. GSE produced indication of cytotoxicity (decreased PCE:NCE ratio) at the 2000 mg/kg dose level for the 48-h harvest time point, confirming that the test article reached the target bone marrow in significant amount. Meganatural GSE and Meganatural GSKE were evaluated as negative in the mouse bone marrow micronucleus assay under the conditions of this assay.     

Tests for mutagenicity in salmonella and covalent binding to DNA and protein in the rat of the riot control agent o-chlorobenzylidene malononitrile (CS)

The aim of this study was to determine whether o-chlorobenzylidene malononitrile (CS) exhibits any genotoxic activity towards Salmonella or mammalian DNA in vivo. CS was synthesized with a [¹⁴C]-label at the benzylic carbon atom. It was administered i.p. at a dose level of 13 mg/kg (1 mCi/kg) to young adult male rats. Liver and kidney DNA was isolated after 8,25, and 75 h. The radioactivity was at (liver, 8 and 75 h) or below (all other samples) the limit of detection of 3 dpm. Therefore, a possible binding of CS to DNA is at least 10⁵ times lower than that of the strong hepatocarcinogen aflatoxin B₁, and 4,000 times lower than that of vinyl chloride. In contrast to this lack of DNA binding, but in agreement with the chemical reactivity of CS, a binding to nuclear proteins could be detected with specific activities ranging between 50 and 121 dpm/mg for liver and between 3 and 41 dpm/mg for kidney. Protein binding could well be responsible for its pronounced cytotoxic effects. CS was also tested in the Ames Salmonella/microsome assay. Strains TA 1535, TA 1537, TA 1538, TA 98, and TA 100 were used with or without pre-incubation. Only with strain TA 100 and only without pre-incubation, a doubling of the number of revertants was detectable at the highest dose levels used, 1,000 and 2,000 g CS per plate. With pre-incubation of TA 100 with CS, a slight increase of the number of revertants was seen at 100 and 500 g per plate, and a subsequent fall below control values at 1,000 g. A check for the number of surviving bacteria revealed a strong bacteriotoxicity of the higher doses of CS so that the calculated mutation frequencies, i.e., the number of revertants per number of surviving bacteria, increased with doses up to 500 g. This toxicity could be counteracted in part by the addition of increasing amounts of rat liver microsomes. In the view of these results, and taking into account the rare and low exposure of man, it is concluded that CS will not create a risk for the induction of point mutations or of carcinogenic processes mediated by DNA binding.     

Mutagenicity Evaluation of Azaperone in the Salmonella/Microsome Test

ABSTRACT

Azaperone was evaluated for its mutagenic potential by the Salmonella/microsome test. No mutagenic activity towards six S. typhimurium strains could be evidenced with azaperone at doses up to 2,000 µg/plate, either without or with metabolic activation at usual test conditions. Higher concentrations of liver post-mitochondrial fraction from Aroclor 1254 (ARO)-pretreated rats did not reveal any increase in the number of revertants towards S. typhimurium strains TA1537, TA1538 and TA98. Moreover, a plate-incorporation test with liver post-mitochondrial fractions from mice pretreated with phenobarbital (PB) and a liquid preincubation test with liver post-mitochondrial fractions from rats pretreated with ARO also failed to reveal any mutagenic action of azaperone towards S. typhimurium strain TA98. Thus, none of the tests used provided any indication of azaperone having a mutagenic action.     

Evaluation of the safety and toxicity of the oligomerized polyphenol Oligonol.

Oligonol((R)) is an optimised phenolic product containing catechin-type monomers and lower oligomers of proanthocyanidin that emanate from a technology process which converts polyphenol polymers into oligomers. In a single dose toxicity study administration of Oligonol (2000mg/kg bw) by gavage for 4 weeks was found to be safe with no side effects (such as abnormal behavior and alopecia). Body weight gain and food consumption were within normal range. Oligonol had no observed toxicity at the dose (1/25 of LD(50)) administered for 6 months. This suggests that Oligonol is safe at repeated human intakes of Oligonol in doses lower than 200mg/day. The highest dose used in this study is equal to 12g daily for an adult man with 60kg body weight. The LD(50) was calculated to be 5.0g/kg body weight (95% confidence limit: 3.5-6.4g/kg). Studies conducted on 30 healthy volunteers consuming Oligonol at doses of 100mg/day and 200mg/day for 92 days showed good bioavailability. The biochemical parameters attesting to liver and kidney functions as well as the hematological parameters were within the normal ranges. The potential of Oligonol to induce gene mutation (a reverse mutation test) was tested using Salmonella typhimurium TA98, TA100, TA104, TA1535, TA153 and Escherichia coli WP2uvrA. Oligonol was not mutagenic to the tester strains. The lack of toxicity supports the potential use of Oligonol as a food or dietary supplement and for use as an additive in pharmaceutical and cosmetological applications.     

Pharmacokinetic and clinical studies of cefuzonam in pediatrics

Pharmacokinetic and clinical studies were conducted to evaluate cefuzonam (L-105, CZON), a new cephem type antibiotic, in the pediatric field. A total of 9 pediatric patients (2-14 years) was treated with intravenous injection of CZON: 4 cases with one shot of 20 mg/kg, 2 cases with one shot of 40 mg/kg and 3 cases with drip infusion over 1 hour of 40 mg/kg. CZON concentrations in serum and the excretion in urine were determined. Mean serum concentrations of CZON after one shot intravenous injection of 20 mg/kg were 49.0, 22.7, 9.03, 2.13, 0.37, and 0.09 micrograms/ml at 15, 30 minutes, 1, 2, 4 and 6 hours, respectively. With 40 mg/kg one shot intravenous injections, mean serum concentrations were 117.5, 68.0, 26.2, 8.80, 0.63 and 0.19 micrograms/ml at 15, 30 minutes, 1, 2, 4 and 6 hours, respectively. With 40 mg/kg intravenous drip infusions over 1 hour, mean concentrations were 57.1, 78.8, 12.9, 1.12 and 0.23 micrograms/ml at 30 minutes, 1, 2, 4 and 6 hours, respectively. Mean half-lives were 0.69 hour for 20 mg/kg one shot injections, 0.44 hour for 40 mg/kg one shot injections, and 0.58 hour for 40 mg/kg 1 hour drip infusions. Urinary recovery rates in 6 hour after administration were 70.8% (mean) for the 20 mg/kg one shot injection, 44.1% (1 case) for the 40 mg/kg one shot injection, and 60.0% (mean) for the 40 mg/kg 1 hour drip infusion. CZON was administered in 26 cases of pediatric infections, and the clinical efficacy, antibacterial activity, and side effects were evaluated. Of the 26 cases 2 were excluded for the reason of not having bacterial infection, and the remaining 24 cases were assessed. Included in the 24 cases were 16 cases of acute pneumonia, 2 cases of acute purulent lymphadenitis, and 1 case each of acute bronchitis, acute purulent otitis media, acute apical periodontitis, staphylococcal scalded skin syndrome (SSSS), acute pyelonephritis, and acute enteritis. Clinical efficacy evaluation showed 19 excellent cases and 5 good cases, with an efficacy rate of 100%. Bacteriologically, Staphylococcus aureus 1 strain, Streptococcus pneumoniae 1 strain, beta-Streptococcus 1 strain, Haemophilus influenzae 10 strains, Haemophilus parainfluenzae 1 strain, Proteus mirabilis 1 strain, and Campylobacter jejuni 1 strain were determined or assumed as pathogens, but all of them were eradicated.(ABSTRACT TRUNCATED AT 400 WORDS)     

Mutagenicity and clastogenicity evaluation of tacrine by Ames and micronucleus assays

Tacrine was evaluated for its mutagenic and clastogenic activities using the Ames bacterial reverse-mutation assay and the rodent bone marrow micronucleus assay. Tacrine was tested for mutagenic potential at six different concentrations, with 1,250 µg/plate as the highest concentration, followed by five lower concentrations with 2-fold spacing. In clastogenic evaluation, tacrine was administered orally to Wistar rats for 2 days at 5, 10, and 20?mg/kg body weights to assess micronucleus induction in bone marrow erythrocytes. In the Ames assay, tacrine showed nonmutagenicity in four tester strains of Salmonella typhimurium viz. TA98, TA100, TA102, and TA1535, but it was found to be mutagenic in the TA1537 tester strain, both in the presence and absence of a metabolic activation system. Tacrine was found to be nonclastogenic on bone marrow cells of rats at all doses tested and was found to be mutagenic in only the TA1537 strain of Salmonella.     

Genotoxic and antimutagenic activities of extracts from pseudocereals in the Salmonella mutagenicity assay

Extracts of amaranth (Amaranthus L.), sorghum (Sorghumbicolor L.) and Japanese millet (Echinochloafrumentacea L.) were evaluated for mutagenicity in Salmonellatyphimurium strains TA98, TA100 and TA102. All three pseudocereal extracts were also assessed for their antimutagenic properties against the direct mutagens 2-nitrofluorene (2NF) for strain TA98, 3-(5-nitro-2-furyl)acrylic acid (5NFAA) for TA100 and H₂O₂ for TA102 strain and against the indirect mutagen aflatoxin B₁ (AFB₁). No mutagenicity was induced by any of the pseudocereal extracts when tested at concentrations as high as 50 mg/ml. All three extracts showed similar antimutagenicity against 5NFAA and no antimutagenicity against 2NF. The number of revertants induced by H₂O₂ extract was inhibited in order amaranth > Japanese milet > sorghum. All extracts were effective in the inhibition of mutagenic activity of aflatoxin B₁. The total polyphenol content as well as the amount of the flavonoids and phenolic acids as main component of polyphenolics were also determined.     

N-benzylimidazole-mediated changes in hepatic drug-metabolizing enzyme activities in Ah-responsive and Ah-non-responsive mice.

1. The inductive effect of N-benzylimidazole (NBI) on hepatic microsomal and cytosolic drug-metabolizing enzyme activities in aryl hydrocarbon (Ah)-responsive C57BL/6N (B6) and Ah-non-responsive DBA/2N (D2) mouse strains was determined and compared with that caused by beta-naphthoflavone (BNF). 2. Relative Ah-responsiveness of the two strains was confirmed by measurement of BNF-induced ethoxyresorufin deethylase (EROD) activity and ELISA immunoquantification. BNF markedly induced EROD activity only in the Ah-responsive B6 mouse strain (65-fold increase). 3. NBI (150 mg/kg per day for 3 days) increased cytochrome P450 concentration similarly in both strains (40 and 60% in B6 and D2 strains, respectively). Compared with BNF treatment of the B6 strain, increases in EROD activity following NBI treatment were only minor. In addition, EROD activity increases were greater in the Ah-nonresponsive D2 strain (300%) than in the Ah-responsive B6 strain (100%) suggesting the possibility of an induction mechanism different from that of recognized Ah receptor agonists. 4. Induction of UDP-glucuronosyltransferase activity (p-nitrophenol acceptor) by BNF was greater in the Ah-responsive B6 strain than in the Ah-non-responsive D2 strain. NBI failed to induce this activity in either strain. 5. Induction of glutathione S-transferase activity towards 1-chloro-2,4-dinitrobenzene following NBI treatment occurred to the same extent (25% increase) as that seen following BNF treatment, in the Ah-responsive B6 strain. Neither xenobiotic affected this activity in the Ah-non-responsive D2 strain. 6. Although NBI is a major inducer, possessing Ah-like inducing properties in rat, it caused only minor changes in murine drug metabolizing enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antihyperglycemic effect of biochanin A, a soy isoflavone, on streptozotocin-diabetic rats

The study was designed to investigate the antihyperglycemic effect of biochanin A on streptozotocin-diabetic rats. Diabetes was induced in adult male albino rats of the Wistar strain, weighing 180-200 g, by administration of streptozotocin (40 mg/kg of body weight) intraperitoneally. Diabetic rats showed increase in plasma glucose and glycosylated hemoglobin and a decrease in plasma insulin and hemoglobin. Activities of gluconeogenic enzymes such as glucose 6-phosphatase, fructose 1,6-bisphosphatase increased and glucokinase, glucose 6-phosphate dehydrogenase decreased in the liver of diabetic rats along with glycogen. Oral administration of biochanin A (10mg/kg body weight) or glibenclamide (600 μg/kg body weight) in 0.5% dimethyl sulfoxide, for 45 days, prevented the above changes and improved towards normality. In addition, protection against body weight loss of diabetic animals by biochanin A was also observed. No significant effect was observed in normal rats treated with biochanin A (10mg/kg bodyweight). These results showed that biochanin A has potential antihyperglycemic activity at a dose of 10mg/kg bodyweight in streptozotocin induced diabetic rats.