Red cell antioxidant enzymes and prognostic indexes in patients with burns

Red cell superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) were measured in 66 burned patients (57 men, 9 women, age 16–78 years). BSAB varied from 15 to 93% and ABSI from 3 to 14 points. In the first week after injury the activity of SOD was significantly decreased as compared with the activity of the enzymes in the control group and was also below the reference values. Later the activity of SOD increased up to the normal range. The activity of CAT followed a similar pattern but the differences were not significant. No significant changes in red cell GPX were found during the monitored period. We did not find any significant association between the antioxidant enzyme activities and the markers of burns severity. On the other side there was a significant indirect association between the change of SOD activity (calculated as a difference between the first week values after the injury and the activities measured later) and BSAB.     

Acute toxicity and sub-chronic toxicity of steroidal saponins from Dioscorea zingiberensis C.H.Wright in rodents

Ethnopharmacological relevance

Steroidal saponins from Dioscorea zingiberensis are widely used in China for curing cardiovascular diseases. However, there was little toxicological information available on them.

Aim of the study

The study evaluated potential toxicity of the steroidal saponins and analyzed the metabolites in rats.

Materials and methods

For the acute study, the steroidal saponins were administered to kunming mice in single doses of 112.5–9000 mg/kg given by gavage. General behavior adverse effects, mortality and liver histopathological changes were examined. For the sub-chronic toxicity study, Sprague–Dawley rats were gavaged at doses of 127.5, 255 and 510 mg/kg/day for 30 days, then examined the biochemical and hematological parameters. Metabolites in serum were analyzed by HPLC–MS.

Results

The steroidal saponins caused dose-dependent general behavior adverse effects, mortality and liver histopathological changes in the acute toxicity study. In the sub-chronic toxicity study, 510 mg/kg/day of steroidal saponins increased total bilirubin (TBIL) in serum and decreased protein content in liver significantly. The metabolic process of TBIL in liver includes TBIL intaking, conjugated bilirubin forming, conjugated bilirubin excreting to biliary passage. Treatment with high dose of the steroidal saponins in vivo may lead to vacuolization of the cytoplasm of hepatocytes and canalicular cholestasis. In all doses used in the experiment, the steroidal saponins decreased aspartate aminotransferase (GOT), alanine aminotransferase (ALT) and alkaline phosphatase (AKP) in serum and increased reduced glutathione hormone (GSH), glutathione reductase (GR) and glutathione S-transferases (GST) in liver. Diosgenin was the main metabolite in serum.

Conclusions

The steroidal saponins did not show any sign of toxicity up to oral dose of 562.5 mg/kg in mice. No significant changes of biochemical and hematological parameters in rats (except at 510 mg/kg/day), it was concluded that the steroidal saponins did not appear to have significant toxicity in their traditional uses.     

Inhibitory effects of Geijigajakyak-Tang on trinitrobenzene sulfonic acid-induced colitis

Aim of the study

Water extract of Geijigajakyak-Tang (GJT) consisting of five crude drugs [dried root of P. lactiflora Peony (Paeoniaceae), dried trunk bark of C. cassia Blume (Lauraceae), seed of Z. jujube var. inermis Mill (Rhamnaceae), fresh root of Z. officinale Rocoe (Zingiberaceae) and dried trunk bark of G. uralensis Fish (Leguminosae)] is a folk medicine used for the treatment of chronic colitis. This study was designed to further elucidate the effect of GJT on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats.

Materials and methods

GJT orally given to mice before and after TNBS intoxication, and their clinical and morphological changes, myeloperoxidase (MPO) activity and malondialdehyde (MDA) levels in colon tissues, were evaluated on Day 8 post-TNBS. Furthermore, the effect of six major constituents of individual herbs on ileum smooth muscle contraction and neutrophil chemotaxis was studied.

Results

GJT had a significant anti-inflammatory effect based on clinical and morphologic changes, MPO activity and MDA levels in colon tissues as compared with sham control. GJT and 5 major active constituents of individual herbs, paeoniflorin, cinnamaldehyde, jujuboside A, jujubogenin, and diammonium glycyrhhizinate significantly inhibited neutrophil chemotaxis. GJT significantly inhibited muscle contraction (IC₅₀; 2.10 ± 0.11 mg/ml), and 1,8-cineol has the most spasmolytic activity (IC₅₀; 0.10 ± 0.03 mg/ml).

Conclusion

GJT has significant anti-inflammatory effects on TNBS-induced colitis via inhibitions of smooth muscle contraction and neutrophil chemotaxis.     

Chemoprevention of liver cancer by plant polyphenols

Primary liver cancer or hepatocellular carcinoma (HCC) is one of the most frequent tumors representing the fifth commonest malignancy worldwide and the third cause of mortality from cancer. Currently, the treatments for HCC are not so effective and new strategies are needed for its fight. Chemoprevention, the use of natural or synthetic chemical agents to reverse, suppress or prevent carcinogenesis is considered an important way for confronting HCC. Many of the chemopreventive agents are phytochemicals, namely non-nutritive plant chemicals with protective or disease preventive properties. In this review, we focus on plant polyphenols, one of the most important classes of phytochemicals, their chemopreventive properties against HCC and discuss the molecular mechanisms accounting for this activity.     

Selective modulation of glucocorticoid receptor function toward development of novel antiinflammation: lessons from a phenylpyrazolosteroid cortivazol

Abstract

A Frequent association of side effects has been a long-standing dilemma in clinical glucocorticoid therapy. Recent progress in molecular biology of glucocorticoid hormone action, however, has prompted researchers to tackle the dissociation of side effects and therapeutic effects based on the assumption that selective modulation of its receptor function could be achieved by as yet unknown compounds. Already a number of selective modulators of the glucocorticoid receptor (SGRMs) have been reported, and certain compounds have dissociating characteristics in vivo. We have addressed ligand-dependent modular recruitment of AF-1 function using a phenylpyrazologlucocorticoid cortivazol, suggesting the possibility of developing tissue-specific SGRMs. It should also be emphasized that SGRMs do not always have a steroid structure.     

Stimulation of serotonin1B receptors induces conditioned place aversion and facilitates cocaine place conditioning in rats

RATIONALE: Changes in serotonin(1B) (5-HT(1B)) receptor function appear to modify the reinforcing properties of cocaine, but the direction of this effect is not completely clear. Pharmacological stimulation of 5-HT(1B) enhanced the rewarding properties of self-administered cocaine while attenuating the threshold-reducing effect of cocaine in the intracerebral brain stimulation procedure. OBJECTIVE: The present study investigates how pharmacological modification of 5-HT(1B) receptor-mediated neurotransmission influence cocaine motivational properties in the conditioned place preference paradigm in rats. METHODS: In separate groups of rats the motivational properties of CP 94,253, a selective 5-HT(1B) agonist, or GR 127935, a 5-HT(1B/D) receptor partial agonist, given alone or in combination, were determined. To evaluate their influence on cocaine-induced place conditioning, CP 94,253, that was found to be aversive, was given every day before each conditioning session, while GR 127935, which given alone had no effect, was administered only before cocaine conditioning sessions. RESULTS: CP 94,253, injected IP at 2.5 and 10 (but not 0.5) mg/kg produced place aversion in the place conditioning paradigm. The aversive effect of 2.5 mg/kg CP 94,253 was completely reversed by 10 mg/kg SC GR 127935. Given before every conditioning session, CP 94,253 did not modify place conditioning by four injections of 10 mg/kg cocaine but at 2.5 mg/kg it potentiated a sub-threshold dose of cocaine. The place preference caused by these two drugs was completely reversed by 10 mg/kg GR 127935. The antagonism by GR 127935 of CP 94,253's effects was shown not to be due to the induction of state-dependent effects. CONCLUSION: The results suggest that stimulation of 5-HT(1B) receptors causes place aversion, and enhances the effect of low doses of cocaine in the conditioned place preference paradigm.     

Serum withdrawal leads to reduced aryl hydrocarbon receptor expression and loss of cytochrome P4501A inducibility in PLHC-1 cells

Changes in the expression of the aryl hydrocarbon receptor (AHR) have been documented in several systems and in response to a variety of treatments. The significance of these findings is unclear, because the effects of such changes on subsequent responses to AHR ligands seldom have been measured. We tested the ability of changes in serum used in cell culture medium to alter expression of the AHR and induction of cytochrome P4501A (CYP1A) in PLHC-1 teleost hepatoma cells. Culture of early-passage cells in serum-free medium for 2 days led to a loss of CYP1A inducibility by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In contrast, culture in 10% delipidated calf serum increased the TCDD-induced levels of both CYP1A protein and enzymatic activity relative to levels in cells cultured in 10% complete calf serum. These effects were consistent between 8 and 24hr post-treatment, indicating that the kinetics of induction were unaffected. In cells cultured in serum-free medium for 1 and 2 days there was a progressive loss of CYP1A inducibility. This loss of response paralleled a time-dependent decline in AHR protein, as measured by specific binding of [3H]TCDD. Using an operational model for AHR action in PLHC-1 cells, the measured reduction in AHR could be shown to predict the loss of CYP1A induction. Expression of AHR protein was unaffected by culture in 10% delipidated serum. The effects of serum-free medium and delipidated serum were found only in early-passage cells; inducibility of CYP1A and expression of AHR protein in late-passage cells were unaffected by serum withdrawal. Comparison of early- and late-passage cells revealed a 2-fold greater rate of proliferation in the latter, suggesting that a growth advantage is coincident with loss of the serum-dependency of AHR expression. These results provide a quantitative link between changes in receptor expression and a downstream response, establishing a foundation for future studies of receptor expression and sensitivity to toxic responses in vitro and in vivo.     

Cloning and characterization of a novel human 5-HT4 receptor variant that lacks the alternatively spliced carboxy terminal exon. RT-PCR distribution in human brain and periphery of multiple 5-HT4 receptor variants.

We have cloned a novel C-terminal splice variant of serotonin 5-HT4 receptors from human hippocampus. The deduced protein extends only one aminoacid past the splicing point. We propose to call the novel variant h5-HT4(n) since it contains none of the C-terminal exons alternatively spliced in other variants. The pharmacological profile of h5-HT4(n) stably expressed in HeLa cells is in agreement with other reported variants. Stably transfected cells showed increased basal levels of intracellular cAMP in absence of agonist, indicating constitutive activity of the expressed receptors. 5-HT induced robust increases of intracellular cAMP. The 5-HT4 receptor antagonist GR 113808 blocked the effects of 5-HT and brought intracellular cAMP below basal constitutive levels, indicating inverse agonism of this compound in this system. The RT-PCR distribution of all known human C-terminal splice variants in human brain regions and periphery showed complex patterns of variant expression, with the novel variant h5-HT4(n) being widely and abundantly expressed.     

Chronic rejection of rat aortic allografts: effect of inhibition of the thromboxane cascade

Non-immunosuppressed rat aortic allografts from DA (RT1^av1) to WF (RT1^u) strain develop, after a short reversible acute rejection episode, chronic arteriosclerotic changes in the vascular wall, which are indistinguishable from those seen in human allografts during chronic rejection [1]. Incubation of the aortic wall segments in vitro and immunochemical assays demonstrated that the allografts synthesized increased amounts of TxB2, but not 6-keto-PGF_1α or LTB4, compared to syngenic or normal aortas. The two major cellular components of the vascular wall, intima and adventitia, were incubated separately after microdissection. TxB2 was produced in the adventitia, whereas most of the 6-keto-PGF₁α was synthesized in the intima. Administration of a specific TxA2 receptor inhibitor to the recipient rat reduced significantly the proliferation of adventitial inflammatory cells and the intimal smooth muscle cells. Nevertheless, it only delayed but did not inhibit the overall sclerosis of the intima.     

5-HYDROXYTRYPTAMINE-INDUCED CONTRACTION OF THE MARMOSET AORTA IS MEDIATED BY A 5-HT1-LIKE RECEPTOR

1. 5-Hydroxytryptamine (5-HT) exerts both contractile and relaxant effects in the marmoset isolated aorta, actions that are unaffected by the 5-HT₂ antagonist ketanserin. The aim of the present study was to define the receptors mediating the contractile activity of 5-HT in the marmoset aorta.
2. Contractile responses were elicited in aortic rings that were either: (i) precontracted submaximally with the thromboxane A₂ agonist U44069 in order to amplify the responses; or (ii) exposed to N ^ω-nitro- L -arginine (100 μmol/L) plus LY 53857 (0.1 μmol/L; a 5-HT₂ receptor antagonist shown previously to inhibit relaxation). The effect of 5-HT on adenosine 3',5'-cyclic monophosphate (cAMP) formation was also investigated.
3. The effects of agonists and antagonists comprised: (i) agonist potencies in the order 5-carboxamidotryptamine > 5-HT > sumatriptan > 8-hydroxy-2-(di- n -propylamino)tetralin; (ii) inhibition of contractile action of 5-HT by the 5-HT_1D antagonist GR 127935; (iii) a contractile response to methysergide; (iv) a lack of effect of tropisetron, an antagonist of 5-HT₃ and 5-HT₄ receptors; and (v) inhibition of forskolin-stimulated cAMP formation by 5-HT (in the presence of LY 53857), indicative of negative coupling to adenylate cyclase.
4. The above effects fulfil the criteria for a 5-HT₁-like receptor. In view of the previous finding that this contractile response is insensitive to ketanserin, it is concluded that the contractile effects of 5-HT in the marmoset aorta are mediated exclusively by a 5-HT₁-like receptor.