Novel squamosamide derivative (compound FLZ) attenuates Abeta25-35-induced toxicity in SH-SY5Y cells

AIM

The aim of the present study was to investigate the protective effect of compound N-[2-(4-hydroxy-phenyl)-ethyl]-2-(2,5-dimethoxy-phenyl)-3-(3-methoxy-4-hydroxy-phenyl)-acrylamide (compound FLZ), a novel synthetic analogue of nature squamosamide, on Abeta25-35-induced toxicity and its active mechanism in human neuroblastoma SH-SY5Y cells.

METHODS

SH-SY5Y cells were pre-incubated with various concentrations of compound FLZ for 30 min and then cultivated with Abeta25-35 (25 micromol/L) for 48 h to induce neurotoxicity. Cell viability, lactate dehydrogenase (LDH) release, and the glutathione (GSH) level were determined by a biochemical analysis. The cell apoptotic ratio and intracellular reactive oxygen species (ROS) level were measured by a flow cytometry analysis. The expression of apoptosis protein (Bcl-2 and Bax) and cytochrome c release were assayed by the Western blot method.

RESULTS

The pretreatment of SH-SY5Y cells with FLZ (1 and 10 micromol/L) markedly increased cell viability and decreased LDH release and morphological injury. Also, FLZ attenuated the Abeta25-35-induced apoptotic cell ratio, regulated the apoptosis protein (Bcl-2 and Bax) expression, and decreased the cytochrome c release from mitochondria. FLZ also significantly inhibited the generation of ROS and the depletion of GSH induced by Abeta25-35 in SH-SY5Y cells.

CONCLUSION

FLZ has protective action against Abeta25-35-induced toxicity in SH-SY5Y cells, which might be mediated through its antioxidant property.

A novel cyclic squamosamide analogue compound FLZ improves memory impairment in artificial senescence mice induced by chronic injection of D-galactose and NaNO2

The aim of the present study was to access the protective effect of a novel synthesized squamosamide cyclic analogue, compound FLZ, on memory impairment in artificially senescent mice induced by chronic injection of D-galactose and sodium nitrite (NaNO(2)). Artificially senescent mouse model was induced by consecutive injection of D-galactose (120 mg/kg) and NaNO(2) (90 mg/kg) once daily for 60 days. Compound FLZ (75 and 150 mg/kg) was orally administered once daily for 30 days after D-galactose and NaNO(2) injection for 30 days. The water maze test was used to evaluate the learning and memory function of mice. The content of malondialdehyde (MDA) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in serum were determined using different biochemical kits. The alterations in hippocampus morphology were assessed by light and electronic microscope. Immunoreactive cells of Bcl-2 in the hippocampus were counted by immunohistochemical staining, and Bcl-2 protein expression was analysed by Western blot method. The results indicate that injection of D-galactose and NaNO(2) induces memory impairment and neuronal damage in hippocampus of mice. In addition, serum SOD and GSH-Px activities decreased, while MDA level increased. Bcl-2-positive neurons and Bcl-2 protein expression in the hippocampus decreased remarkably. Oral administration of FLZ for 30 days significantly improved the cognitive deficits and the biochemical markers mentioned above, and also reduced the pathological alterations in mouse hippocampus. The results suggest that FLZ ameliorates memory deficits and pathological injury in artificially senescent mice induced by chronic injection of D-galactose and NaNO(2), indicating that FLZ is worth further studies for fighting antisenescence and dementia.

Dactylorhin B reduces toxic effects of β-amyloid fragment (25–35) on neuron cells and isolated rat brain mitochondria

beta-amyloid is strongly implicated in Alzheimer's pathology, and mitochondria play an important role in neurodegenerative disorders. Dactylorhin B [short for bis(4-beta-D-glucopyranosyloxybenzyl)-2-beta-D-glucopyranosyl-2-isobutyltartrate (DHB)] is an active compound isolated from Coeloglossum viride. (L.) Hartm. var. bracteatum (Willd.) and may have neuroprotective effects. In the present study, we investigated the damage of rat brain mitochondrial function induced by beta-amyloid and the protective effect of DHB. Isolated rat brain mitochondria were incubated with amyloid-beta peptide (Abeta)(25-35) alone or together with DHB. reactive oxygen species production, pyruvate dehydrogenase complex activity, alpha-ketoglutarate dehydrogenase complex activity, cytochrome c oxidase activity, mitochondrial swelling, mitochondrial membrane potential and the release of cytochrome c from mitochondria were measured. Data showed that Abeta(25-35) directly disrupted mitochondrial function, inhibited the key enzymes and contributed to apoptosis and the deficiency of energy metabolism. Co-incubation of DHB attenuated Abeta(25-35)-induced pathological changes. The significance of DHB in the management of mitochondria-related disorders is discussed.

Magnocellular and parvocellular visual pathways have different blood oxygen level-dependent signal time courses in human primary visual cortex

PURPOSE

The magnocellular and parvocellular pathways (M and P pathways) are the major pathways of the visual system, with distinct histologic and physiologic properties that may also have different metabolic characteristics. We hypothesize that the differences of the 2 visual pathways would also manifest as differences in the signal time course of blood oxygen level-dependent functional MR imaging (BOLD fMRI). The differences in BOLD signal time course may provide insight into the metabolic requirements of the 2 pathways.

METHODS

Eleven fMRI sessions on 6 subjects were performed using stimuli that preferentially activated the 2 pathways. Regions commonly activated by both the M and P stimuli in the primary visual cortex (V1) were determined, and the contrast elicited by the stimulus, time-to-peak (TTP), and the full width at half maximum (FWHM) of the BOLD signal time course were measured.

RESULTS

The functional stimuli activated cortical regions described previously in the literature, such as V1, V4, and V5. Within V1, the TTP of the signal time course of the 2 stimuli were statistically different, with the P stimulus generating TTPs that were on average 12% faster than the M stimulus (P = .0037).

CONCLUSION

We have demonstrated the ability to functionally differentiate the M and P stimuli in a commonly activated anatomic region. Because the BOLD response is dependent on the ratio of oxyhemoglobin and deoxyhemoglobin in the blood, the difference in the BOLD time course between the 2 stimuli suggests that the oxygen demand of the 2 pathways may be different.

The anti-hepatitis drug DDB chemosensitizes multidrug resistant cancer cells in vitro and in vivo by inhibiting P-gp and enhancing apoptosis

PURPOSE

DDB (dimethyl-4,4'-dimethoxy-5,6,5'6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate) is a synthetic hepatoprotectant which has been widely used to treat chronic viral hepatitis B patients in China for more than 20 years. In this study, we evaluated DDB as a multidrug resistance (MDR) chemosensitizing agent.

METHODS

A panel of sensitive and resistant cancer cell lines were treated with various concentration of DDB, and the effect on chemosensitivity and accumulation of anticancer drugs; promotion of apoptosis and P-glycoprotein (P-gp) expression were determined by MTT (Dimethyl thiazolyl-2,5-diphenyltetrazolium bromide) assay, fluorospectrometry and flow cytometry respectively. Drug resistance reversal activity of DDB was also examined in BALB/c nude mice bearing both acquired MDR human nasopharyngeal carcinoma KBv200 and parental KB xenografts. The effect of DDB on the pharmacokinetics of Dox and hematological toxicity induced by Dox was measured in ICR and C(57)/BL mice, respectively.

RESULTS

DDB at nontoxic concentrations of 12.5, 25 and 50 microM partly reversed the resistance to vincristine, doxorubicin, paclitaxel in acquired MDR breast carcinoma MCF-7/Adr cells, KBv200 and intrinsic MDR human hepatocarcinoma Bel(7402) cells, whereas no chemosensitizing effect of DDB was observed in sensitive KB and MCF-7 cells. DDB increased the intracellular accumulation of doxorubicin and inhibited surface P-gp expression in MCF-7/Adr cells. Furthermore, it was found that DDB promoted doxorubicin-induced apoptosis of Bel(7402) cells through enhanced caspase-3 activation. Co-administration of DDB at 300 and 500 mg/kg orally to nude mice increased the antitumor activity of vincristine to KBv200 xenografts without a significant increase in toxicity. In contrast, Co-administration of DDB did not inhibit the growth of KB xenografts. DDB also markedly reduced the decrease of leukocytes in doxorubicin-treated C(57)/BL mice. Co-administration of DDB increased Dox concentration in ICR mice bearing S180 sarcoma, but no pharmacokinetical interaction with Dox was observed.

CONCLUSION

These results indicate that DDB has MDR reversal activity by inhibiting P-gp and when used in combination with anti-cancer drugs, it could potentially be used as a clinical treatment for P-gp-mediated MDR cancers.

[Protective action of ulinastatin against lipopolysaccharides-induced acute lung injury in mice and the relation of it to iNOS and c-Jun expressions]

AIM

To study the protective action of ulinastatin against lipopolysaccharide (LPS)-induced acute lung injury in mice and the mechanism of its action.

METHODS

Mice were intraperitoneally injected with ulinastatin (50 and 100 ku x kg(-1)) or saline at a period of 12 h, separately, 30 min after the last injection of ulinastatin, except normal control, all mice of other groups were injected a dose of LPS 15 mg x kg(-1) via tail vein. The levels of TNFalpha in serum and lung were measured by ELISA. The expression of TNFalpha mRNA and iNOS mRNA in lung was assayed by RT-PCR. The expression of c-Fos and c-Jun protein in lung was measured by Western blotting method. And the NO2- / NO3- level in serum and MDA in lung were measured with kits.

RESULTS

The levels of NO2- / NO3- and TNFalpha in serum, MDA and TNFa in lung all increased after iv injection of LPS. The expressions of TNFa mRNA, iNOS mRNA, c-Fos and c-Jun in lung of LPS-injected mice were enhanced. Pretreatment with ulinastatin 100 ku x kg(-1) decreased the levels of NO2- / NO3- in serum and lung, reduced the index of lung, and inhibited the expressions of iNOS mRNA and c-Jun in lung induced by LPS in mice, while ulinastatin showed no effect on TNFa level in serum and lung.

CONCLUSION

Ulinastatin protected mice from acute lung injury induced by lipopolysaccharides via inhibiting the activation of c-Jun and iNOS mRNA expression.

[Protective effects of bicyclol on liver fibrosis induced by carbon tetrachloride]

OBJECTIVE

To study the protective effects and related mechanism of bicyclol on liver fibrosis induced by carbon tetrachloride (CCl(4)).

METHODS

Forty male Wistar rats were injected subcutaneously with 25% CCl(4) twice a week for 3 months. Since the 7th week the rats were divided into 4 groups of 10 rats: normal control group, CCl(4) model group, bicyclol 100 mg/kg group (perfused of bicyclol into stomach 100 mg/kg qd for 45 days), and bicyclol 200 mg/kg group (perfused of bicyclol into stomach 200 mg/kg qd for 45 days). Twenty-four hours after the last administration the rats were killed. The serum was isolated to measure the levels of alanine transaminase (ALT), aspartate aminotransferase (AST), total bilirubin (TB), albumin/globulin (A/G), total protein (TP), hyaluronic acid (HA), and pro-collagen peptide III (PIIIP). Serum TNF alpha content was examined by ELISA assay, and liver TGF beta 1 level was determined by immunohistologic assay. The pathology of liver was examined. Twenty-eight mice were divided into 4 groups of 7 mice: normal control group, subacute group, 100 mg bicyclol group (perfused of bicyclol into stomach 50 mg/kg bid), and bicyclol 200 mg/kg group (perfused of bicyclol into stomach, 100 mg/kg bid), and 200 mg bicyclol group. Carbon tetrachloride was injected subcutaneously to the mice in the latter 3 groups every 3 days for 1 month. Twenty-four hours after the last administration the mice were killed and the serum was isolated to measure the levels of ALT, AST, TP, and albumin. Mitochondria were extracted from the livers of the experimental animals to measure the amount of protein. Mitochondrial glutathione (GSH) and malondialdehyde (MDA) contents were measured. The MDA and GSH contents in the control group were regarded as 100%, and the percentages of MDA and GSH in other groups were calculated. The fluidity of mitochondrial membrane and swelling degree of mitochondria were measured. Imunohistochemistry was used to detect the liver TGF beta 1. Nuclear NF kappa B DNA binding activity was investigated by electrophoretic mobility shift assay.

RESULTS

Three months after the administration of carbon tetrachloride the serum ALT, AST, TB, HA, and PIIIP levels of the CCl(4) model group increased by 24, 10, 8, 28, and 4 times and the levels of albumin and A/G decreased significantly in comparison with those of the normal control group. However, the serum ALT, AST, TB, HA, and PIIIP levels in the 2 bicyclol groups were significantly lower than those in the model group. The pathological changes in the liver of the 2 bicyclol groups were significantly lighter than those in the model group. The serum TNF alpha increased significantly in the model group, however, the serum TNF alpha levels in the 2 bicyclol groups were significantly lower than that of the model group. The liver TGF beta 1 level in the model group was 4 times that of the normal control group. The liver TGF beta 1 level in the 2 bicyclol groups were significantly lower than that of the model group. One month after the administration of carbon tetrachloride to mice the serum ALT and AST increased and A/G decreased significantly. However, in the 2 bicyclol groups the serum ALT and AST were significantly lower and the A/G ratio was significantly higher in comparison with the model group. The mitochondrial GSH decreased by 34% and the mitochondrial MDA increased by 60% in the model group. The mitochondrial GSH was normal in the 2 bicyclol groups and the MDA level was significantly lower than that of the model group. The fluidity and swelling ability of mitochondrial membrane significantly decreased in the model group mice and the fluidity and swelling ability of mitochondrial membrane in the 2 bicyclol group mice were relatively normal. Twelve and twenty-four hours after the damage by carbon tetrachloride the binding activity of nuclear NF kappa B remained very high in the model group mice and was significantly lower in the 2 bicyclol group mice in comparison with the model mice.

CONCLUSION

Bicyclol alleviates CCl(4)-induced liver fibrosis by its anti-peroxidation and anti-inflammation functions and regulation of NF-kappa B DNA-binding activity.

Coeloglossum viride var. bracteatum extract attenuates D-galactose and NaNO2 induced memory impairment in mice

The aim is to study the neuroprotective effects of CE, a special extract from Coeloglossum viride (L.) Hartm. var. bracteatum (Willd.), on memory deficits in senescent mice induced by consecutive injection of d-galactose and NaNO(2) for 60 days. Oral administration of CE (2.5 mg kg(-1), 5 mg kg(-1)) started from 47th day of the experiment. Water maze test was used to evaluate the learning and memory function of mice. The contents of MDA and GSH and the activities of SOD and GSH-px in brain tissue were determined using different biochemical methods. The alterations in hippocampus morphology were assessed. Immunoreactive cells of Tau-2 and NT-3 in the hippocampus were counted by immunohistochemical staining. The results indicated that combined injection of d-galactose and NaNO(2) induced memory impairment of mice. In addition, SOD and GSH-px activities and GSH level decreased while MDA level increased in mouse brain. Tau-2 positive neurons increased while NT-3 positive neurons decreased remarkably in the hippocampus. Administration of CE for 14 days significantly improved the cognitive deficits and the biochemical markers mentioned above and reduced the histological lesions in mouse brain. These results suggest that CE is worth testing for further preclinical study aimed for senescence and dementia.

Chemopreventive effect of dimethyl dicarboxylate biphenyl on malignant transformation of WB-F344 rat liver epithelial cells

AIM

To study the potential chemopreventive effect of dimethyl dicarboxylate biphenyl (DDB), an anti-hepatitis drug, on hepatocarcinogenesis in vitro.

METHODS

The anti-carcinogenesis effect of DDB was assessed on a two-stage chemical oncogenesis model induced by 3-methylcholanthrene and 12-O-tetradecanoyl phorbol 13-acetate (TPA) with WB-F344 rat liver epithelial cells (WB-F344 cells) in vitro. A soft-agar colony formation assay was used to determine the tumorigenic potential of the transformed WB-F344 cells. The gap junctional intercellular communication (GJIC) was detected using the scrape loading/dye transfer technique.

RESULTS

DDB at 1 micromol/L, 2 micromol/L, and 4 micromol/L significantly prevented the malignant transformation of WB-F344 cells induced by 3-methylcholanthrene and TPA. The average number of transformed foci decreased dramatically by 10.0%, 37.2%, and 47.4%, respectively. In soft agar, a remarkable decrease in colony numbers was observed in transformed cells treated with 2 micromol/L and 4 micromol/L DDB. DDB at 1 micromol/L, 2 micromol/L, and 4 micromol/L inhibited the downregulation of GJIC induced by TPA in a dose-dependent manner. The GJIC recovered to 25.6%, 34.6%, and 44.9%, respectively, of the control WB-F344 cells by DDB.

CONCLUSION

DDB has a potential chemopreventive effect on hepato-carcinogenesis induced by carcinogens in vitro.

Effect of diphenyl dimethyl bicarboxylate on concanavalin A-induced liver injury in mice

Diphenyl dimethyl bicarboxylate (DDB) is a hepatoprotectant and used in the treatment of chronic viral hepatitis patients in China. The aim of the present paper was to investigate the effect of DDB on liver injury mediated by immune response in concanavalin A (Con A)-treated mice. A dose of Con A 30 mg/kg was injected via the tailvein to induce liver injury in mice. Serum alanine transaminase (ALT), aspartate aminotransferase (AST), total bile acid (TBA), total bilirubin (TBIL) and tumor necrosis factor alpha (TNF-alpha) level as well as liver TNF-alpha mRNA expression were determined. The following results were obtained: (1) Prior oral administration of DDB 150 mg/kg markedly reduced the elevated serum ALT, TBA and TBIL levels, and the liver lesions in Con A-treated mice; (2) DDB significantly inhibited the elevation of serum TNF-alpha and liver TNF-alpha mRNA expression 2 h after Con A injection; (3) DDB significantly inhibited hepatocyte nuclear DNA fragmentation 12 h after Con A injection; (4) DDB dose-dependently prevented the direct DNA damage induced by CuSO(4)-Phen-Vit C-H(2)O(2) system in vitro, and the ex vivo experiment also showed that the administration of DDB reduced the susceptibility of mouse liver nuclei DNA to CuSO(4)-Phen-Vit C-H(2)O(2) system. These results suggest that DDB could directly protect hepatocyte DNA from oxidative damage, and inhibit TNF-alpha mRNA expression in liver tissue, which resulted in prevention of liver damage induced by Con A in mice.

[Protective effects of bicyclol on liver fibrosis induced by carbon tetrachloride]

OBJECTIVE

To study the protective effects and related mechanism of bicyclol on liver fibrosis induced by carbon tetrachloride (CCl(4)).

METHODS

Forty male Wistar rats were injected subcutaneously with 25% CCl(4) twice a week for 3 months. Since the 7th week the rats were divided into 4 groups of 10 rats: normal control group, CCl(4) model group, bicyclol 100 mg/kg group (perfused of bicyclol into stomach 100 mg/kg qd for 45 days), and bicyclol 200 mg/kg group (perfused of bicyclol into stomach 200 mg/kg qd for 45 days). Twenty-four hours after the last administration the rats were killed. The serum was isolated to measure the levels of alanine transaminase (ALT), aspartate aminotransferase (AST), total bilirubin (TB), albumin/globulin (A/G), total protein (TP), hyaluronic acid (HA), and pro-collagen peptide III (PIIIP). Serum TNF alpha content was examined by ELISA assay, and liver TGF beta 1 level was determined by immunohistologic assay. The pathology of liver was examined. Twenty-eight mice were divided into 4 groups of 7 mice: normal control group, subacute group, 100 mg bicyclol group (perfused of bicyclol into stomach 50 mg/kg bid), and bicyclol 200 mg/kg group (perfused of bicyclol into stomach, 100 mg/kg bid), and 200 mg bicyclol group. Carbon tetrachloride was injected subcutaneously to the mice in the latter 3 groups every 3 days for 1 month. Twenty-four hours after the last administration the mice were killed and the serum was isolated to measure the levels of ALT, AST, TP, and albumin. Mitochondria were extracted from the livers of the experimental animals to measure the amount of protein. Mitochondrial glutathione (GSH) and malondialdehyde (MDA) contents were measured. The MDA and GSH contents in the control group were regarded as 100%, and the percentages of MDA and GSH in other groups were calculated. The fluidity of mitochondrial membrane and swelling degree of mitochondria were measured. Imunohistochemistry was used to detect the liver TGF beta 1. Nuclear NF kappa B DNA binding activity was investigated by electrophoretic mobility shift assay.

RESULTS

Three months after the administration of carbon tetrachloride the serum ALT, AST, TB, HA, and PIIIP levels of the CCl(4) model group increased by 24, 10, 8, 28, and 4 times and the levels of albumin and A/G decreased significantly in comparison with those of the normal control group. However, the serum ALT, AST, TB, HA, and PIIIP levels in the 2 bicyclol groups were significantly lower than those in the model group. The pathological changes in the liver of the 2 bicyclol groups were significantly lighter than those in the model group. The serum TNF alpha increased significantly in the model group, however, the serum TNF alpha levels in the 2 bicyclol groups were significantly lower than that of the model group. The liver TGF beta 1 level in the model group was 4 times that of the normal control group. The liver TGF beta 1 level in the 2 bicyclol groups were significantly lower than that of the model group. One month after the administration of carbon tetrachloride to mice the serum ALT and AST increased and A/G decreased significantly. However, in the 2 bicyclol groups the serum ALT and AST were significantly lower and the A/G ratio was significantly higher in comparison with the model group. The mitochondrial GSH decreased by 34% and the mitochondrial MDA increased by 60% in the model group. The mitochondrial GSH was normal in the 2 bicyclol groups and the MDA level was significantly lower than that of the model group. The fluidity and swelling ability of mitochondrial membrane significantly decreased in the model group mice and the fluidity and swelling ability of mitochondrial membrane in the 2 bicyclol group mice were relatively normal. Twelve and twenty-four hours after the damage by carbon tetrachloride the binding activity of nuclear NF kappa B remained very high in the model group mice and was significantly lower in the 2 bicyclol group mice in comparison with the model mice.

CONCLUSION

Bicyclol alleviates CCl(4)-induced liver fibrosis by its anti-peroxidation and anti-inflammation functions and regulation of NF-kappa B DNA-binding activity.

Metamagnetic transition in Na 0.85 CoO2 single crystals

We report the magnetization, specific heat, and transport measurements of a high quality Na(0.85)CoO2 single crystal in applied magnetic fields up to 14 T. At high temperatures, the system is in a paramagnetic phase. It undergoes a magnetic phase transition below approximately 20 K. For the field H||c, the measurement data of magnetization, specific heat, and magnetoresistance reveal a metamagnetic transition from an antiferromagnetic state to a quasiferromagnetic state at about 8 T at low temperatures. However, no transition is observed in the magnetization measurements up to 14 T for H perpendicular c. The low temperature magnetic phase diagram of Na(0.85)CoO2 is determined.

Reversal of multidrug resistance of cancer through inhibition of P-glycoprotein by 5-bromotetrandrine

PURPOSE

The present study aimed to evaluate the MDR reversal activity of bromotetrandrine (BrTet), a bromized derivative of tetrandrine (Tet), in vitro and in vivo.

METHODS

Drug sensitivity was determined using the MTT assay. The in vivo effect of Tet was investigated using nude mice grafted with sensitive and resistant KB human epidermoid cancer cells. Doxorubicin (Dox) accumulation was analyzed by fluorospectrophotometry and the protein and mRNA levels of P-glycoprotein (P-gp) were determined by immunocytochemistry and RT-PCR, respectively.

RESULTS

BrTet at 0.25, 0.5 and 1 micro M reversed Dox resistance in MDR human breast cancer MCF-7/Dox cells dose-dependently and its potency was greater than that of Tet at the same concentrations. BrTet reversed vincristine (VCR), Dox and paclitaxel resistance in MDR human oral epidermoid carcinoma KBv200 cells as well as innate VCR and Dox resistance in human hepatocellular carcinoma Bel(7402) cells. However, BrTet showed no effect on the IC(50) values of the above-mentioned anticancer drugs in sensitive MCF-7 and KB cells. No reversal effect of BrTet on the cytotoxicity of 5-fluorouracil and cisplatin, non-P-gp substrates, was observed. In nude mice bearing KBv200 xenografts on the left flank and KB xenografts on the right flank, i.p. injection of 5 mg/kg and 10 mg/kg BrTet significantly enhanced the antitumor activity of Dox against KBv200 xenografts with inhibitory rates of 33.0% and 39.2%, while Dox alone inhibited the growth of KBv200 xenografts by only 11.6%. No enhancement by BrTet was seen in KB xenografts. Moreover, BrTet at 5 mg/kg reversed paclitaxel resistance in KBv200 xenografts. Fluorospectrophotometric assay showed that BrTet significantly increased the intracellular accumulation of Dox in MCF-7/Dox cells in a dose-dependent manner. BrTet also inhibited the overexpression of P-gp in MCF-7/Dox cells, but had no effect on mdr1 expression.

CONCLUSIONS

BrTet showed significant MDR reversal activity in vitro and in vivo. Its activity may be related to the inhibition of P-gp overexpression and the increase in intracellular accumulation of anticancer drugs. BrTet may be a promising MDR modulator for eventual assessment in the clinic.

[Synthesis and antioxiactivity of squamosamide cyclic analogs]

OBJECTIVE

To design and synthesize a series of squamosamide cyclic analogues and to test their antioxidation activity.

METHODS

Eleven 3-substituted indole-2-one derivatives were designed and synthesized through 9 steps with p-hydroxyphenylacetic acid as the starting material and their structures were confirmed by nuclear magnetic resonance and mass spectrometry.

RESULTS

Eleven compounds showed antioxidation activity and the activities of compounds 9 and 13 matches the positive control FLZ-52.

CONCLUSION

Cyclic reconstruction with FLZ-52 as the lead compound have some antioxidation activity.

[Xanthones from Tibetan medicine Halenia elliptica and their antioxidant activity]

OBJECTIVE

To investigate the xanthones from Tibetan medicine Halenia elliptica and their antioxidant activity.

METHODS

Column chromatography over normal phase silica gel, reversed phase silica gel, Sephadex LH-20, and recrystallization techniques were used to isolate and purify constituents from Halenia elliptica. Infrared spectrometry, mass spectrometry, and nuclear magnetic resonance spectrometry were used to identify the structure of compounds. The antioxidant activity was evaluated by measuring the content of malondialdehyde product in mice liver cell microsomal induced by ferrous-cysteine.

RESULTS

Eight xanthones (compound I-VIII) were isolated and identified from the ethyl acetate extract of Halenia elliptica, among which 1,7-dihydroxy-2,3,5-trimethoxyxanthone was a novel compound. Compound I, III at 10 microg/ml and 100 microg/ml could inhibit the production of malondialdehyde in mouse liver microsomes in vitro.

CONCLUSION

Eight xanthones were isolated and they have certain antioxidant activity.

Isorhapontigenin and resveratrol suppress oxLDL-induced proliferation and activation of ERK1/2 mitogen-activated protein kinases of bovine aortic smooth muscle cells

The objective of our study was to compare the inhibitory effect of isorhapontigenin (ISO) and resveratrol, two natural antioxidants, on oxidized low-density lipoprotein (oxLDL)-induced proliferation of bovine aortic smooth muscle cells (BASMCs) and its relation to reactive oxygen species (ROS) generation and extracellular signal-regulated kinase 1/2 activation. The results showed that stimulation of oxLDL (50-150 microg/mL) for 48 hr induced a dose-dependent increase in cell number and incorporation of [3H]thymidine into DNA of BASMCs. Western blot analysis demonstrated that oxLDL (150 microg/mL) stimulated an evident phosphorylation of p42/44 MAP kinases in BASMCs. Incubation of BASMCs with oxLDL induced significant increase in ROS detected by using an oxidant-sensitive fluorescent probe of 2',7'-dichlorofluorescin diacetate. The level of H2O2 in the medium of cultured BASMCs also increased markedly. Preincubation of BASMCs with ISO and resveratrol significantly inhibited oxLDL-induced cell proliferation and incorporation of [3H]thymidine, and the phosphorylation of p42/44 MAP kinases in BASMCs as well. Furthermore, preincubation of BASMCs with ISO and resveratrol attenuated oxLDL-induced increases in ROS and H2O2 levels. The results suggested that oxLDL-induced acute formation of ROS and subsequent activation of redox-sensitive extracellular signal-regulated kinase 1/2 MAPK pathways, which might be important for mitogenic signaling of oxLDL in vascular smooth muscle cells. The inhibitory effect of ISO and resveratrol on oxLDL-induced mitogenesis of BASMCs might be taken through blocking the generation of ROS and activation of the ERKs pathway.

Effect of PYCNOGENOL on the toxicity of heart, bone marrow and immune organs as induced by antitumor drugs

PYCNOGENOL is a mixture of water-soluble bioflavonoids extracted from the bark of pine trees growing in the southwest coastal region of France. In the present paper the effects of PYCNOGENOL (Pyc) on the toxicity of bone marrow, heart and immune organs induced by anticancer drugs were investigated, in mice. The following results were obtained: 1. Pyc at the orally-administered dose of 200 and 150 mg/kg body wt. markedly prevented the elevation of serum creatine phosphokinase (CPK) activity and the decrease of heart rate in mice treated with doxorubicin (Dox); 2. Pyc at 100 and 150 mg/kg body wt. significantly antagonized the inhibition of DNA synthesis in thymus induced by subcutaneous injection of cyclophosphamide (Cyc); 3. Pyc at 150 and 200 mg/kg body wt. markedly induced increase of erythrocytes and hemoglobin, but had no effect on leukopenia, in Cyc-treated mice; and 4. Pyc has no antagonizing effect on the anticancer activity of Dox and Cyc. All the results suggest that Pyc possesses a protective effect on the cardiotoxicity of Dox and the inhibition of thymus DNA synthesis induced by Cyc in mice.

[Inhibition of human low-density lipoprotein oxidation by salvianolic acid-A]

AIM

Oxidized low-density lipoprotein (LDL) is involved in the development of atherosclerosis. Oxidative modulation of serum LDL is related to oxygen free radicals. Antioxidants have beneficial effects on oxidative modulation of LDL and development of atherosclerosis. Salvia miltriorhiza (Danshen) preparations have been widely used in the treatment of cardio-cerebral vascular diseases in China. Salvianolic acid A (Sal-A), one of the components of Salvia miltriorhiza, was shown to have strong antioxidative activity. The aim of this investigation was to evaluate the effect of Sal-A on human LDL oxidative modulation mediated by copper ions.

METHODS

Oxidation of human LDL was performed in pH 7.4 phosphate-buffered saline with 10 mumol.L-1 CuSO4 at 37 degrees C water for 20 h. The content of malondialdehyde (MDA), lipofuscin and vitamin E in LDL as well as the rate of electrophoretic mobility (REM) of LDL were measured. The generation of free radicals during LDL oxidation was detected by low level-chemiluminescence (LL-CL). The chelation of Cu2+ by Sal-A was detected by UV-spectrum scanning.

RESULTS

Sal-A (10(-6) to 10(-4) mol.L-1) was shown to markedly reduce the production of MDA and lipofuscin as well as the consumption of vitamin E during LDL oxidation. Sal-A (10(-4) mol.L-1) was also shown to inhibit the increase of REM of LDL caused by oxidative modification. In addition, the spectrum of LL-CL showed that Sal-A (10(-6) to 10(-5) mol.L-1) decreased the generation of free radicals during LDL oxidation in a dose dependent manner. The differential UV-spectrum of Sal-A in the presence of Cu2+ indicated that Sal-A could chelate copper ions.

CONCLUSION

Sal-A has inhibitory effect on Cu2+ mediated human LDL oxidation through chelating Cu2+ and scavenging free radicals.

Functional magnetic resonance imaging of the visual system

Functional magnetic resonance imaging (fMRI), which is a technique useful for non-invasive mapping of brain function, is well suited for studying the visual system. This review highlights current clinical applications and research studies involving patients with visual deficits. Relevant reports regarding the investigation of the brain's role in visual processing and some newer fMRI techniques are also reviewed. Functional magnetic resonance imaging has been used for presurgical mapping of visual cortex in patients with brain lesions and for studying patients with amblyopia, optic neuritis, and residual vision in homonymous hemianopia. Retinotopic borders, motion processing, and visual attention have been the topics of several fMRI studies. These reports suggest that fMRI can be useful in clinical and research studies in patients with visual deficits.

[Effect of bicyclol on acetaminophen-induced hepatotoxicity: energetic metabolism and mitochondrial injury in acetaminophen-intoxicated mice]

AIM

To investigate the mechanism of the protective effect of bicyclol on acetaminophen-induced hepatotoxicity in mice.

METHODS

31P-MRS spectra in vivo were determined by using surface coil technique. The membrane fluidity of mitochondria and the activity of mitochondrial ATPase were also determined by spectrofluorophogometry and spectrophotometry methods.

RESULTS

The hepatotoxicity of acetaminophen is related to the lipid peroxidation and covalent binding to macromolecules, which leads to damage of mitochondrial function. Our results showed that the decrease of ATP/Pi and the elevation of PME/ATP in acetaminophen-intoxicated mice were significantly inhibited by two doses of bicyclol (100, 200 mg.kg-1) pretreatment, which indicate that bicyclol has significant protective effect on the decrease of liver ATP content induced by acetaminophen. Acetaminophen significantly inhibited the activity of mitochondrial ATPase by its cytotoxic metabolite NAPQI [N-acetyl-p-benzoquinone], which has the potential to react with sulfhydryl groups or through sulfhydryl group oxidation. Our results showed that the reduction of mitochondrial fluidity as well as the inhibitory effect of mitochondrial ATPase induced by acetaminophen were also reduced by bicyclol.

CONCLUSION

The effect of bicyclol on acetaminophen-induced liver injury maybe partly due to its protective effects on hepatic energy metabolism and mitochondria function.

Oculomotor synkinesis following a midbrain stroke

A 33-year-old man developed a complete third nerve palsy in the setting of acute bacterial endocarditis. MRI revealed an ischemic stroke in the cerebral peduncle involving the third nerve fascicle. Subsequently, he was observed to have paradoxic elevation of the eyelid on adduction and downgaze. To the authors' knowledge, this is the first demonstration of oculomotor synkinesis after an acquired, ischemic CNS lesion.

Antioxidative activity of natural isorhapontigenin

Isorhapontigenin (ISOR), isolated from Belamcanda chinensis, is a derivative of stilbene. Its chemical structure is very similar to that of resveratrol, with a potent antioxidative effect. In the present study, we investigated the antioxidative activity of ISOR in vitro. Oxidative damage of rat liver microsomes, brain mitochondria and synaptosomes was induced by Fe2+-Cys, VitC-ADP-Fe2+ and H2O2, respectively. The formation of malondialdehyde (MDA), decrease of reduced glutathione (GSH) and increase of ultra-weak chemiluminescence during the lipid peroxidation process were determined. In addition, the characteristic ultra-weak chemiluminescence of oxidative DNA damage induced by CuSO4-Phen-VitC-H2O2 system was studied. The results showed that ISOR significantly inhibited MDA formation in liver microsomes, brain mitochondria and synaptosomes induced by Fe2+-Cys. Also, ISOR markedly prevented the decrease of GSH in mitochondria and synaptosomes induced by H2O2 and the increase of ultra-weak chemiluminescence during lipid peroxidation induced by VitC-ADP-Fe2+ as well as oxidative DNA damage induced by CuSO4-Phen-VitC-H2O2. The effects of ISOR at 10(-5) and 10(-6) mol/L on the MDA formation and decrease of GSH were similar to that of the classical antioxidant vitamin E (10(-4) mol/L). It may be concluded that ISOR possessed potent antioxidative activity and was much more potent than vitamin E.

Functional magnetic resonance imaging of eye dominance at 4 tesla

We studied eye dominance in visual cortex and lateral geniculate nucleus (LGN) using functional magnetic resonance imaging (fMRI) at a very high magnetic field (4 tesla). Eight normal volunteers were studied with fMRI at 4 tesla during alternating monocular visual stimulation. The acquisition was repeated twice in 4 subjects to confirm reproducibility. In addition, magnetic resonance signal intensities during three conditions (right eye stimulation, left eye stimulation, and control condition) were compared to determine whether the observed area was truly or relatively monocular in 2 subjects. In both the individual and group analyses, the anterior striate cortex was consistently activated by the contralateral eye more than the ipsilateral eye. Additionally, we found evidence that there were areas in the bilateral LGN which were more active during the stimulation of the contralateral eye than during the stimulation of the ipsilateral eye. The activated areas were reproducible, and the mean ratio of the overlapping area was 0.71 for the repeated scans. The additional experiment revealed that the area in the anterior visual cortex could be divided into two parts, one truly monocular and the other relatively monocular. Our finding confirmed previous fMRI results at 1.5 tesla showing that eye dominance was observed in the contralateral anterior visual cortex. However, the eye dominance in the visual cortex was found not only in the most anterior area corresponding to the monocular temporal crescent but also in the more posterior area, presumably showing the greater sensitivity of the temporal visual field (nasal retina) as compared with the nasal visual field (temporal retina) in the peripheral visual field (peripheral retina). In addition, it is suggested that the nasotemporal asymmetry of the retina and the visual fields is represented in the LGN as well as in the visual cortex.

Visual loss in childhood

An eight-year-old girl presented with vision loss and optic atrophy. Neuro-imaging revealed a sellar mass, which when biopsied proved to be a chiasmatic/hypothalamic glioma. The differential diagnosis of a sellar mass in childhood is discussed, and the presentation and management of chiasmatic/hypothalamic gliomas is reviewed.

Effects of check size on visual cortex activation studied by functional magnetic resonance imaging

We studied functional magnetic resonance imaging (fMRI) of visual cortex during checkerboard visual stimulation with three standard check sizes to examine whether activation in the visual cortex varied among these sizes. We acquired fMRI at 1.5 T in 8 normal subjects, each receiving the best refractive correction. Each subject underwent an experiment consisting of four conditions: black and white checkerboards with three check sizes (0.25-, 0.5-, and 1.0-degree) flickering at 8 Hz, and a black screen. SPM96 was used for a group data analysis with a random effects model after each of the subject's data was motion-corrected and spatially normalized to a standard brain. The activation in the visual cortex showed the greatest signal changes with the 0.5-degree check among the three check sizes. When standard check sizes are used to stimulate visual cortex in fMRI experiments, our results suggest that 0.5-degree checks flickering at 8 Hz produce the most vigorous activation in visual cortex.