[Electrocardiogram characteristics of patients with ventricular arrhythmia originating from the distal great cardiac vein]

Objective: To explore the electrocardiographic characteristics of patients with idiopathic ventricular arrhythmias (VAs) originating from different portions of distal great cardiac veins (DGCV). Methods: The study included 49 patients underwent successful RFCA of premature ventricular complex(PVCs)/ventricular tachycardia(VT) from different portions of the DGCV in our department from July 2009 to March 2016. The surface 12-lead electrocardiogram (ECG) and intraventricular ablation mapping features were analyzed. Patients were divided into four groups according to the mapping and ablation results: DGCV1(10 patients), DGCV2 (13 patients), proximalanterior interventricular vein (PAIV, 17 patients)and extend distal great cardiac vein (EDGCV, 9 patients). We analyzed the similarities and differences between surface 12-lead ECG of patients with PVCs/VT from different portions of DGCV, and compared with random chosen 290 patients with PVCs/VT from ventricular outflow tract and adjacent structure. Results: A positive R wave in inferior leads, a negative QS morphology in lead aVL and aVR were found among all groups. The different characteristics of surface 12-lead ECG of VAs originating from DGCV were as follows: (1)EDGCV patients demonstrated a positive R or r wave on lead Ⅰ(6/9) while a negative rS or qr wave was evidenced in other three groups (39/40). (2)A positive R pattern on lead V(1), V(5)-V(6) (11/13) was presented in patients of DGCV2 group; R (without S or s) wave on V(1) (9/10), RS or Rs wave on V(5)-V(6) were found in DGCV1 group; RS or rS wave was seen on lead V(1), R(without S)wave in lead V(5)-V(6) (25/26) were found in EDGCV and PAIV group and the amplification of R wave in EDGCV was higher than V(1) of PAIV group.(3)Precordial lead transition zone was in front of V(1) for DGCV1 and DGCV2 groups (23/23), within V(1)-V(3) for EDGCV group, but on V(2) or within V(2)-V(3) for PAIV group.(4)Patients of DGCV1 and DGCV2 demonstrated a longer Pseudo delta wave time(PdW), intrinsicoid deflection time (IDT), significantly larger maximum deflection index (MDI) than those in PAIV and EDGCV groups (P<0.001). (5)The different characteristics of surface 12-lead ECG between VAs originating from DGCV and those from ventricular outflow tract and adjacent structure were as follows: ① The ECG features were similar between PVIA and LCC group, both demonstrated a rs wave on the lead Ⅰ, rS wave on V(1)-V(2) and R wave on V(5)-V(6); ②The ECG features were similar betweenEDGCV and RCC group, both presented with R or r wave on the lead Ⅰ, the QRS wave of precordial leads was similar as PAIV and LCC groups; ③A R wave on the lead V(1), V(5)-V(6) was found in group DGCV2, and ILCC; ④Similar to the group Endo-MAA, patients in DGCV1 group also demonstrated a R wave on the lead V(1) and a Rs wave on V(5)-V(6). Conclusion: A positive R wave in inferior leads, a negative QS morphology in lead aVL and aVR are seen in all patients, but different electrocardiographic characteristics of PVC/VT originating from the different portions of the DGCV are presented on lead Ⅰ and V(1)-V(6).

[Diagnosis and treatment value of colposcopy and loop electrosurgical excision procedure in microinvasive cervical cancer: analysis of 135 cases]

OBJECTIVE

To explore the sensitivity and specificity of colposcopy directed biopsy (CDB) and the value of loop electrosurgical excision procedure (LEEP) for the diagnosis and treatment of microinvasive cervical cancer (MCC).

METHODS

One hundred and thirty five patients with MCC were diagnosed with LEEP in Obstetrics and Gynecology Hospital, Fudan University from April 2008 to November 2010, and were retrospectively analyzed on CDB diagnoses and following treatment after LEEP. According to patient's desire for preservation of fertility and cone margin status, following strategies after LEEP included follow-up, second LEEP, hysterectomy, modified radical hysterectomy and radical hysterectomy. Single and multiple factors related to residual lesions after LEEP were analysed with Pearson Chi-square test and logistic regression model, respectively.

RESULTS

CDB diagnosed MCC with a sensitivity of 4.4 % (6/135), specificity of 100.0% (4 680/4 680), and false negative rate of 95.6% (129/135). Among the 135 patients, 29 did not receive further treatment in our hospital and lost contact. One hundred and six patients had secondary treatment or follow-up in our hospital, 4 of among which were closely followed up; one hundred and two received further treatment, which included 6 cases with second LEEP (3 received extrafascial hysterectomy after repeat LEEP), 59 cases hysterectomy, 14 cases modified radical hysterectomy and 26 cases radical hysterectomy. For factors related to residual lesions after LEEP, single factor analysis showed that the ratio of residual lesion in patients aged 27-39, 40-49 and 50-65 years were respectively 19.0% (11/58), 15.4% (10/65) and 5/12 (χ(2)=4.505, P=0.105). Residual lesions occurred in 24.7% (23/93) of patients with positive LEEP margins, which was more than that 7.1% (3/42) of patients with negative LEEP margins (χ(2)=5.756, P=0.016). The ratio of residual lesions in patients with positive endocervical, ectocervical and deep stromal margins were respectively 29.6%(8/27), 17.1%(7/41) and 30.6%(11/36; χ(2)= 2.275, P=0.321). Residual lesions in patients with or without lymph vascular space invasion (LVSI) were 2/7 and 18.8% (24/128), respectively (χ(2)=0.412, P=0.521). The ratio of residual lesions in patients with invasion depth of <1 mm was 17.1% (7/41), 1-<3 mm was 19.0% (16/84), and 3-5 mm was 3/10, with no significant difference among three groups (χ(2)=0.870, P=0.647). Logistic regression analysis showed positive cone margin (OR=5.069, P=0.014) and age (OR=1.080, P=0.024) were the independent risk factors of residual lesions after LEEP conization.

CONCLUSIONS

CDB alone is not adequate for the diagnosis of MCC. For young patients who desire to preserve fertility with a negative cone margin, close follow-up is acceptable. Cone margin status and age are two independent risk factors for residual lesions after LEEP.

Antiapoptotic and antioxidant effects of rosmarinic acid in astrocytes

The protective effects of rosmarinic acid (RA), a polyphenolic compound, on apoptosis induced by hydrogen peroxide in astrocytes were studied. Pretreating cells with RA significantly increased cell viability and decreased apoptosis rate induced by H2O2. The antiapoptotic effect of RA was further confirmed by increase of mitochondrial membrane potential and inhibition of caspase-3 activity. RA also attenuated cellular oxidative stress by decreasing the amount of reactive oxygen species and malondialdehyde. Results clearly show that RA was able to attenuate H2O2-induced cell injury by its antiapoptotic and antioxidant activity.

The serum of rats administered flavonoid extract from Epimedium sagittatum but not the extract itself enhances the development of rat calvarial osteoblast-like cells in vitro

The flavonoid extract from Epimedium sagittatum (FES) has been found by us to be effective in preventing osteoporosis induced by ovariectomy in rats. In the present study, the effect of FES on the development of rat calvarial osteoblast-like (ROB) cells was investigated. No appreciable effect was observed when ROB cells were exposed to FES in vitro. However, serum isolated from rats administered FES orally was able to significantly stimulate the proliferation as well as the osteoblastic differentiation of ROB cells compared to serum from control rats. The results indicate that the serum of rats administered FES contains active metabolites ofFES that enhance the development of osteoblasts, while the original form of FES itself is inactive.

Scavenging effects of natural phenols on oxidizing intermediates of peroxynitrite

Most of peroxynitrite (ONOO-/ONOOH) is formed via the diffusion-limited reaction between nitric oxide and superoxide. In biological systems, the decomposition of ONOO- yields 30-35% of carbonate radical (CO3*-) and nitrogen dioxide (NO2*), which are strongly oxidizing intermediates and are suggested to take a part of the responsibility for the toxicity of nitric oxide (NO*) or ONOO-. Therefore, the current study focuses on the scavenging activities of phenols toward CO3*- and NO2* to protect biomolecules from damage caused by NO* or ONOO- using the technique of pulse radiolysis. From the build-up kinetic of the phenoxyl radicals and the decay kinetic of CO3*- radical, the rate constants of scavenging reactions were determined to be 1.9-3.4 x 10(8) M(-1) x s(-1) and 0.11-1.9 x 10(8) M(-1) x s(-1) for CO3*- and NO2* respectively. The results indicated that the tested phenols are the efficient scavengers of CO3*- and NO2*.

Fast repair of the poly G hydroxyl radical adduct by two phenylpropanoid glycosides

The repair activities and the reaction mechanisms of two phenylpropanoid glycosides (PPGs), isolated from a herb used in Chinese folk medicine, towards the oxidizing hydroxyl radical adduct of poly G were studied with a pulse radiolytic technique. On pulse irradiation of a nitrous oxide saturated 4 mM aqueous solution of poly G containing one of the tested compounds, the transient absorption spectrum of the hydroxyl radical adduct of poly G decays with the formation of that of the phenoxyl radical of the tested compound within several tens microseconds after the electron pulse irradiation. The results indicated that there was a repair reaction between the hydroxyl radical adduct of poly G and the compounds tested. The rate constants for the repair reactions of poly G hydroxyl radical adducts by verbasicoside and cistanoside C were determined to be 1.4 and 1.0 x 10(9) M(-1) x s(-1), respectively.

Docking study of cistanoside C to telomeric DNA fragment

Experiments show that the natural products phenyl propanoid glycosides (PPGs) extracted from the plant Pedicularis spicata are capable of repairing DNA damaged by oxygen radicals. Based on kinetic measurements and experiments on tumor cells, a theoretical study of the interaction between PPG molecule Cistanoside C and telomeric DNA fragment has been carried out. The docking calculations performed using JUMNA software showed that the Cistanoside C could be docked into the minor groove of telomeric DNA and form complexes with the geometry suitable for an electron transfer between guanine radical and the ligand. Such complexes can be formed without major distortions of DNA structure and are further stabilized by the interaction with the saccharide side-groups.

Ascorbic acid induces redifferentiation and growth inhibition in human hepatoma cells by increasing endogenous hydrogen peroxide

The mechanisms of redifferentiation and growth inhibition induced in human hepatoma cells by ascorbic acid (AA) were studied. After treatment with AA, the content of hydrogen peroxide (H2O2) and the activity of superoxide dismutase (SOD) increased in a concentration- and time-dependent manner, while the activity of catalase (CAT) decreased in a concentration- and time-dependent manner. Using 6 mM AA as a positive control, after treatment by 50 microM hydrogen peroxide, the malignant characteristics of human hepatoma cells were alleviated; for example as cell surface charge markedly decreased, the electrophoresis rate dropped from 1.68 microns.s-1.V-1.cm-1 to 0.97, the average of alpha-fetoprotein content decreased from 327 micrograms.g-1 protein to 193, and gamma-glutamyl-transpeptidase activity fell from 0.84 U.g-1 protein to 0.30. The indexes related to cell differentiation were promoted, such as tyrosine-alpha-ketoglutarate transaminase activity increased from 17.1 mumol.g-1 protein to 33.1, and the colonogenic potential decreased by 79.3%. SOD and 3-amino-1,2,4-triazole (AT) exhibited some effects, but there were statistically significant differences between the SOD, AT and H2O2 or AA groups. AA induced growth inhibition and redifferentiation of human hepatoma cells through the production of hydrogen peroxide, since addition of SOD (200 units/ml), an enzyme that dismutates superoxide and generates hydrogen peroxide, and AT (1.5 mM), a CAT inhibitor that inhibits the activity of CAT and leads to an increase in H2O2 content, showed some inducing changes emphasizing the involvement of reactive oxygen species (ROS) in redifferentiation of hepatoma cells. AA can cause the content of H2O2 to increase, and the factor H2O2 showed a similar effect to AA on growth and redifferentiation suggests that H2O2 is involved in hepatoma cell redifferentiation. In conclusion, these results suggest that AA inhibits tumor growth and induces tumor redifferentiation by virtue of producing H2O2.

Effects of ascorbic acid and sodium selenite on growth and redifferentiation in human hepatoma cells and its mechanisms

After being treated with ascorbic acid (AA) 3 mM + sodium selenite (SS) 1.5 microM, the growth rate and mitotic index of human hepatoma cells BEL-7402 decreased remarkably. The indexes related to cell malignancy were improved, such as cell surface charge obviously decreased, the electrophoresis rate fell from 1.76 microns.s-1.V-1.cm-1 to 0.93, the average of alpha-fetoprotein (alpha-FP) content decreased from 341 micrograms.g-1 protein to 92, and gamma-glutamyl-transpeptidase (gamma-GT) activity from 0.76 U.g-1 protein to 0.19. The indexes related to cell differentiation were affected favourably, such as the level of tyrosine-alpha-ketoglutarate transaminase (TAT) activity increased from 14.2 mumol.g-1 protein to 49.0, and the colonogenic potential decreased 95.3%. These results indicated that hepatoma cells had been successfully induced to redifferentiation by AA + SS. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were significantly higher, while the activity of catalase (CAT) was slower in the treated group than in the control group. The malondialdehyde (MDA) content decreased slightly, reduced glutathione (GSH) decreased sharply, and H2O2 content increased dramatically. In conclusion, these results indicate that the combination of ascorbic acid and sodium selenite may induce the redifferentiation of hepatoma cells and inhibit cell growth by virtue of enhancing the activities of antioxidative enzymes and reducing the formation of H2O2, and altering the cell redox status. The combination of ascorbic acid and sodium selenite may be a potent anticancer treatment option for human hepatoma cells.

Theoretical study of fast repair of DNA damage by cistanoside C and analogs: mechanism and docking

Experiments show that the natural substances phenylpropanoid glycosides (PPGs) extracted from pelicularis spicata are capable of repairing DNA damaged by oxygen radicals. Based on kinetic measurements and experiments on tumor cells, a theoretical study of the interaction between PPG molecules and isolated DNA bases, as well as a DNA fragment has been performed. An interaction mechanism reported early has been refined. The docking calculations performed using junction minimization of nucleic acids (JUMNA) software showed that the PPG molecules can be docked into the minor groove of DNA and form complexes with the geometry suitable for an electron transfer between guanine radical and the ligand. Such complexes can be formed without major distortions of DNA structure and are further stabilized by the interaction with the rhamnosyl side-groups.

Effects of diethyldithiocarbamate on proliferation, redifferention, and apoptosis in human hepatoma cells

AIM

To examine the effects of diethyldithiocarbamate (DDC) on the proliferation, redifferentiation, and apoptosis in human hepatoma cells.

METHODS

Cell surface charge, biochemical changes, cell growth in soft agar, single cell electrophoresis, electron microscopy examination, and flow cytometry analysis were measured.

RESULTS

After being treated with DDC 3 mmol/L the growth curve and mitotic index of human hepatoma cells decreased remarkably, and the cellular growth inhibitory rate amounted to 52.4 %. The indices related with cell malignancy were alleviated significantly, such as the cell surface charge decreased significantly, the electrophoresis rate dropped from 1.6 to 0.8 micron . s-1 . V-1 . cm-1, the average value of alpha-fetoprotein (alpha-FP) content decrease d from 314 to 95 microg/g (protein), and gamma-glutamyl-transpeptidase (gamma-GT) activity from 0.9 to 0.14 U/g (protein). The cell differentiation index increased significantly, such as the average levels of tyrosine-alpha-ketoglutarate transaminase (TAT) activity increased from 11.6 to 36 micromol/g (protein), and the colonogenic potential decreased by 95.6 %. The apoptotic bodies, detached cells, and apoptotic morphological features appeared, and the treated cells DNA was fragmented as observed by the comet assay. The flow cytometric results showed that a 42.9 % fractional DNA content existed in the treated cells.

CONCLUSION

DDC can inhibit human hepatoma cells proliferation, and can induce redifferentiation as well as apoptosis.

Down-regulation of four arsenic antagonists on apoptosis and telomerase activity induced by arsenic trioxide in three myelocytic leukemia cell lines

AIM

To investigate regulative effects of thiol reagents, N-acetyl-l-cysteine (NAC) and natrii dimercaptosussinas (NDMS), catalase (CAT), and calcium chelator 2-[(2-bis-[carboxymethyl]-amino-5-methyl-phenoxy)-met]-6-methoxy-8-bis-[carboxy-methyl]-aminoquinoline (Quin 2) on apoptosis and telomerase activity induced by arsenic trioxide (As2O3) in three myelocytic leukemia cell lines.

METHODS

Flow cytometry was used to examine apoptosis and a PCR ELISA kit was used to detect telomerase activity.

RESULTS

As2O3 induced about 40 % - 60 % of apoptosis in NB4, K562, and HL-60 cells at the concentration of 0.6, 2.7, and 8.1 micromol/L respectively, as well as down-regulated telomerase activities in three cell lines. NAC 4 mmol/L, NDMS 200 micromol/L, CAT 80 kU/L, and Quin 2 20 micromol/L could down-regulate apoptosis variously induced by As2O3. NAC and CAT alone could decline telomerase activity in three cell lines and further decline telomerase activities that had been decreased by As2O3, whereas Quin 2 antagonized the decline in K562 and HL-60 cells.

CONCLUSION

Thiol activity loss, free radical alteration, intracellular calcium changes, and decline of telomerase activity might be involved in As2O3-induced apoptosis. NAC, NDMS, CAT, and Quin 2 antagonized in some extent the effect of As2O3 on the three tested cell lines.

Hydrogen peroxide induces apoptosis in human hepatoma cells and alters cell redox status

Direct exposure of human hepatoma cell line SMMC-7721 to hydrogen peroxide (H2O2) can induce apoptosis. Apoptosis induced by H2O2 was inhibited by cycloheximide, actinomycin D, 3-aminobenzamide, EGTA or Zn2+. H2O2 can increase the level of intracellular Ca2+, downregulate GSH levels, slightly induce lipid peroxidation, and lead to change in the ratio of reduced ion components to oxidized ion components of cells. Analysis of flow cytometry indicates that H2O2 decreases the level of Bcl-2. The data indicate that H2O2-induced apoptosis requires new mRNA and protein syntheses; H2O2 can activate Ca2+/Mg2+-dependent endonuclease leading to internucleosomal DNA fragmentation and activation of poly (ADP-ribose) polymerase interfering with the energy metabolism of the cell. The H2O2 downregulation of GSH may be more important for apoptosis than H2O2 induction of lipid peroxidation, and the H2O2 induced changes in redox status of the cell may be among the original events which lead up to other biochemical changes.

Alleviation of pre-exposure to low-dose 16O8+ ion on mouse testicular histological damage induced by subsequent high-dose irradiation

The testes of the B6C3F1 hybrid strain mice were irradiated with 0.05 Gy of 16O8+ ion as the pre-exposure dose (D1), and were then irradiated with 2 Gy of 16O8+ ion as challenging radiation dose (D2) at 4 h after per-exposure. Testicular morphology was observed by light microscope at 35th day after radiation. The results showed that irradiation of mouse testes with 2 Gy of 16O8+ ion significantly impaired, mainly reduction of tubule diameter and decrease or loss of germ cells in various developing stages, especially spermatogenic elements. Pre-exposure to a low-dose (0.05 Gy) of 16O8+ ion significantly alleviated above mentioned damage on testicular morphology induced by subsequent a high-dose (2 Gy) radiation.

Effects of ascorbic acid and DL-alpha-tocopherol on human hepatoma cell proliferation and redifferentiation

AIM

To examine the effects of ascorbic acid (AA) and DL-alpha-tocopherol (alpha T) on the proliferation and redifferentiation of human hepatoma cell.

METHODS

Choosing an all-trans retinoic acid (RA) as a positive control, cell surface charge, biochemical changes, and cell growth in soft agar were measured.

RESULTS

After treatment with AA 4 mmol.L-1 and alpha T 1 mmol.L-1 together, the growth curve and mitotic index of human hepatoma cells decreased remarkably, the cellular growth inhibitory rate amounted to 61.3%. The indices related to cell malignancy alleviated significantly; cell surface charge decreased, the electrophoresis rate dropped from 1.64 to 0.89 microns.s-1.V-1.cm-1, the average value of alpha-fetoprotein (alpha-FP) content decreased from 300 to 80 micrograms.g-1 (protein), and gamma-glutamyl-transpeptidase (gamma-GT) activity decreased from 0.81 to 0.201 U.g-1(protein). The index related to cell differentiation increased significantly, such as the average level of tyrosine-alpha-ketoglutarate transaminase activity increased from 10.6 to 45 micrograms.g-1 (protein), and the colonogenic potential decreased by 96.6%.

CONCLUSION

AA and alpha T combination inhibited human hepatoma cell proliferation, induced redifferentiation, and reversed its malignant phenotypic characteristics.

[Induced-differentiation and cytotoxicity of isoverbascoside on HL-60 cells]

HL-60 cells were treated by isoverbascoside with different time and different concentrations in vitro. The differentiation of HL-60 cells was evaluated by light and electron microscopy to observe morphological changes, by chemiluminence to detect phagocytosis and by tumorigenesis in nude mice to determine malignancy. The cytotoxical effect of isoverbascoside on HL-60 cells was examined by trypan blue excluding staining and electron microscopy. The influence of isoverbascoside on cell cycle was measured by flow cytometry. Granular differentiation of HL-60 cells was induced by isoverbascoside at 20-25 mumol/L within 1-3 days as the results of morphological changes, enhancement of phagocytosis and decreasing of tumorigenesis. Strong cytotoxicity was evidenced in HL-60 cells treated by isoverbascoside at 30-35 mumol/L. HL-60 cells treated by isoverbascoside at 20 mumol/L were delayed at G1 phase at 12 hours and G2/M phase at 72 hours.

Retardation of skeletal muscle fatigue by the two phenylpropanoid glycosides: verbascoside and martynoside from Pedicularis plicata maxim

The effects of the phenylpropanoid glycosides verbascoside and martynoside from Pedicularis plicata were investigated on muscle contractility in Bufo gastrocnemius muscle electrically stimulated in vitro. The maximum amplitude and maintained time of contraction were mechanically recorded and used as indices of muscle contractility. After 30 min pretreatment of the muscle, verbascoside at 20.0 microM resisted muscle fatigue significantly while martynoside at 80.0 microM improved muscle contractility only slightly. These two glycosides resisted muscle fatigue depending on their antioxidative activities, which is in agreement with the role of reactive oxygen species (ROS) in promoting fatigue in skeletal muscle.

Effects of ascorbic acid on human hepatoma cell proliferation and redifferentiation

AIM

To examine the effects of ascorbic acid (AA) on hepatoma.

METHODS

Choosing an all-trans tretinoin (Tre) as a positive control, cell growth, and cell redifferentiation tests by cell surface charges, biochemical changes, and cell growth in soft agar were measured.

RESULTS

After being treated with AA 6 mmol.L-1, the growth curve and mitotic index of human hepatoma cells decreased remarkably, the cellular growth inhibitory rate amounted to 58.9%. The indices related with cell malignancy alleviated, such as cell surface charge obviously decreased, the electrophoresis rate dropped from 1.64 microns.s-1.V-1.cm-1 to 0.93, the average value of alpha-fetoprotein (alpha-FP) content decreased from 302 micrograms.g-1(protein) to 90, and gamma-glytamyl-transpeptidase (gamma-GT) activity from 0.81 U.g-1(protein) to 0.16. The index related with cell differentiation increased, such as the average level of tyrosine-alpha-ketoglutarate transminase activity increased from 10.3 micromol.g-1(protein) to 41.2, and the colonogenic potential decreased 94.4%.

CONCLUSION

AA can inhibit human hepatoma cells proliferation, induce redifferentiation, and reverse its malignant phenotypic characteristics.

Effects of 16O+6 ion irradiation on human sperm spontaneous chemiluminescence, motility, acrosome reaction and viability in vitro

Effects of 16O+6 ion irradiation with different doses on human sperm spontaneous chemiluminescence (SCL), motility, acrosome reaction (AR) and viability were examined. Spermatozoa were irradiated with 0, 0.25, 0.5, 1, 2, 4, 8, 16, 32, or 64 Gy 16O+6 ion beam at the energy of 3.17 MeV/u. After irradiation, samples were analyzed by SCL measurement at 1, 2 and 3 h of incubation; motility was determined by the transmembrane migration method within 2 h of incubation; the percentage of AR and viability was evaluated by the triple-stain technique at 3.5 h of incubation. The results showed: sperm SCL was significantly increased with irradiation doses and the lowest effective dose was 0.5 Gy; compared with controls, the transmembrane migration ratio of spermatozoa progressively elevated with irradiation doses at 0.5, 1, and 2 Gy; the percentage of sperm AR markedly increased in 0.5-4 Gy irradiation and the optimal dose was 2 Gy, and then significant decreased with further increase of irradiation doses; the viability had no significant change within 0.25-8 Gy, but was progressively decreased at 16, 32 and 64 Gy. These data suggested that heavy ion at low doses increased motility and AR, whereas had deleterious effects at higher doses, which are associated with free radical reactions induced by heavy ion irradiation.

[Relationships between lipid peroxidation or cyclic nucleotides and motility in human asthenozoosperm and normosperm]

The relationships between sperm lipid peroxidation (LP) or cyclic nucleotides and sperm motility in normospermic and asthenozoospermic specimens were analyzed. Sperm motility was measured by the transmembrane migration method; LP was measured by thiobarbituric acid (TBA) method and the intracellular cAMP and cGMP contents was measured by radioimmunoassay in 20 fertile and 20 asthenozoospermic infertile human semen specimens. Results showed that in both fertile and infertile individual, there was a close negative correlation between sperm LP formation and motility (r = -0.76; P < 0.001 and r = -0.68; P < 0.001); there were significant positive correlations between intracellular cAMP (r = 0.64; P < 0.01 and r = 0.59; P < 0.01) or cGMP (r = 0.60; P < 0.01 and r = 0.55; P < 0.05) and sperm motility; and the correlation between LP and motility was the closest. These results suggest a causative role for LP in the aetiology of male infertility due to defective sperm motility, and confirmed that intra-cellular cyclic nucleotides likely also have influences on sperm motility.

Apoptosis, redifferentiation and arresting proliferation simultaneously triggered by oxidative stress in human hepatoma cells

The effects of oxidative stress (ascorbic acid-ferrous system) on the proliferation, differentiation and apoptosis of the human hepatoma cell SMMC-7721 were studied. Oxidative stress significantly inhibited cell proliferation and induced morphological differentiation. Whatever the indices related with cell malignancy, such as alpha-fetoprotein and c-glutamyltranspeptidase or the index related with cell differentiation, such as tyrosine-alpha-ketoglutarate transaminase, all inclined evidently to normalization. The tumour's clonogenic potential decreased significantly. Moreover, together with differentiation, the phenomenon of apoptosis was found by the appearance of apoptotic bodies, detached cells, and apoptotic morphological feature. Although, their DNA was not degraded into oligonucleosomal fragmentation, the DNA was cut into larger fragments (about 21.2 kbp) of a size associated with chromatin loops. These findings indicated that oxidative stress can induce both differentiation and apoptosis simultaneously in tumour cells. All the results showed that oxidative stress may initiate the tumour cells reverse transformation. The possible mechanism of the differentiation and apoptosis induced by oxidative stress may be related to the lipid peroxidation of cell membrane.

[Effects of oxidative stress on the proliferation, differentiation and apoptosis in the human hepatoma cells]

The human hepatoma cells SMMC-7721 were treated with different concentrations of ascorbic acid (50-800 mumol/L) and FeSO4 (2.5-40 mumol/L) system to generate oxidative stress at various degrees. The oxidative stress induced by the system were mainly contributed to hydroxyl radical. All the various degrees of oxidative stress in this study are able to inhibit the proliferation of hepatoma cells. While low levels of oxidative stress may cause hepatoma cells lost some malignant features, such as aggregation of Con-A to the cell surface, alpha-fetoprotein, gamma-glutamyltransepeptidase and tyrosine-alpha-ketoglutarate transaminase, all of the 4 indices tended to cell differentiation, coloning efficiency potential decreased significantly, and apoptotic cells appeared. The numbers of apoptotic cells increased with the increasing of oxidative stress. The apoptotic cells exhibited non-adherent, smaller, chromatin condensed around the periphery of the nucleus in the shape of crescent, nuclear fragmentations but with intact cellular membrane, and DNA degraded to around 21.2 kbp fragment. All of the results showed that there is possibility to inhibit hepatoma cells growth, to promote differentiation and apoptosis, and therefore to initiate reverse transformation via strict regulation of oxidative stress.

Chromosomal aberrations induced by 12C6+ heavy ion irradiation in spermatogonia and spermatocytes of mice

The testes of Kun-Ming strain mice were radiated with different doses of 12C6+ ion or 60Co gamma-ray. Chromosomal aberrations induced in spermatogonia and spermatocytes were analyzed by the air-drying method. The relative biological effectiveness (RBE) of 12C6+ ion was calculated with respect to 60Co gamma-ray for the induction of chromosomal aberrations. The 12C6+ ion and 60Co gamma-ray dose-response relationships for chromosomal aberrations were plotted by linear quadratic models. The results showed that there was an increase in frequency of chromosomal aberrations in all the treated groups compared to controls. The RBE values were 1.67 for aberrations of spermatogonia and 1.66 for aberrations of spermatocytes for a dose of 2.0 Gy. Moreover, a different distribution of the various types of aberrations has been found for 12C6+ ion and 60Co gamma-ray irradiations. The dose-response relationships for 12C6+ ion and 60Co gamma-ray exhibited negative curvature in both spermatogonia and spermatocytes groups: the frequencies of aberrations increased sharply at low doses and exhibited less sharp increases for higher doses, which may be related to an interaction between the chromosomal damage and a block in cell cycle. Our results may provide useful information for the assessment of genetic risks of humans exposed to heavy ions.

Effects of pre-exposure of mouse testis with low-dose (16)O8+ ions or 60Co gamma-rays on sperm shape abnormalities, lipid peroxidation and superoxide dismutase (SOD) activity induced by subsequent high-dose irradiation

PURPOSE

To investigate the effects of pre-exposure of mouse testis with low-doses of (16)O8+ ions or 60Co gamma-rays on sperm shape abnormalities, lipid peroxidation and superoxide dismutase (SOD) activity induced by subsequent high-dose irradiation.

MATERIALS AND METHODS

Testes of the B6C3F1 hybrid strain mice were pre-irradiated with 0.05 Gy of (16)O8+ ions or 60Co gamma-rays and then after 4 h given a test irradiation with 2 Gy of the same radiation type. SOD activity and thiobarbituric acid reactive substances (TBARS) in the testes were determined by spectrophotometric and TBA methods respectively at 4 h after irradiation. Testis weight, sperm count and sperm morphology were analysed at day 35 after irradiation.

RESULTS

Compared with controls, there was a significant increase in SOD activity and a significant decrease in TBARS level of pretreated testes. Testis weight loss, sperm count reduction and sperm abnormalities were significantly lower in the pretreated testes. The bioeffects of a 2 Gy dose of (16)O8+ ions relative to 60Co gamma-rays were 1.84 +/- 0.28 for testis weight, 1.22 +/- 0.25 for sperm count and 1.29 +/- 0.10 for sperm abnormalities.

CONCLUSIONS

These data suggest that pre-exposure of testes with a low dose of heavy ions or gamma-rays renders the organ more resistant to subsequent high-dose irradiation. The increase of SOD activity and the decrease of lipid peroxidation levels induced by low-dose ionizing irradiation may be involved in this resistance. The effects with heavy ion irradiation were greater than with gamma-rays.

Tretinoin or retinol enhancement of lymphokine-activated killer cell proliferation and cytotoxicity against human bladder cancer cells in vitro

AIM

To study the effect of tretinoin (Tre) or retinol (Ret) on the proliferation of lymphokine-activated killer (LAK) cells in patients with transitional cell cancer of bladder and their cytolysis to bladder tumor cells.

METHODS

LAK cell proliferation was assayed in the presence of either Tre or Ret by cell counting. Human transitional bladder cancer cell lines BIU-87, EJ, or bladder tumor cells (BTC) from patients with bladder cancer were used as target cells and cytotoxicity of LAK cells was determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

The proliferation of LAK cells induced by interleukin-2 (IL-2) was stimulated by Tre or Ret (10-100 nmol.L-1). The cytotoxicity of LAK cells against BIU-87, EJ cells, or BTC was enhanced by pretreatment of LAK cells with Tre or Ret 10-100 nmol.L-1.

CONCLUSION

Tre or Ret enhances the proliferation and cytotoxicity of LAK cells from patients with bladder cancer. Retinoids are potential in adoptive immunotherapy of bladder cancer.

Effects of ferulic acid on fertile and asthenozoospermic infertile human sperm motility, viability, lipid peroxidation, and cyclic nucleotides

The capacity of human sperm fertilization principally depends on sperm motility and membrane integrity. Reactive oxygen species, such as superoxide anion and hydrogen peroxide, are known to impair sperm motility and membrane integrity by inducing membrane lipid peroxidation (LPO). Ferulic acid (FA), an effective constituent in various medicinal herbs, has recently been shown to scavenge oxygen free radicals and increase the intracellular cAMP and cGMP. The aim of this study is to investigate the effects of FA on human sperm motility, viability, lipid peroxidation, and cyclic nucleotides in fertile and asthenozoospermic infertile individuals in vitro. The sperm samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Washed spermatozoa were incubated at 37 degrees C in Ham's F-10 medium with 0, 0.1, 0.2, 0.4, 0.8, or 1.6 mM of FA. Samples were analyzed for viability, determined by eosin-Y dye exclusion method at 0, 1, 2, 3, 5, and 6 h of incubation; motility, determined by the trans-membrane migration method within 2 h of incubation; LPO, determined by thiobarbituric acid (TBA) method at 3 h of incubation and the intracellular cAMP and cGMP, determined, respectively, by 3H-cAMP and 125I-cGMP radioimmunoassay at 3 h of incubation. The results showed: in both fertile and infertile spermatozoa, the viability, trans-membrane migration ratio (TMMR) and the levels of intracellular cAMP and cGMP in FA-treated spermatozoa were significantly higher than those of spermatozoa in control groups, while TBA-reactive substances contents in treated spermatozoa were significantly lower than those in control spermatozoa. The effects of FA on these processes were concentration dependent. These data suggested that FA is beneficial to sperm viability and motility in both fertile and infertile individuals, and that reduction of lipid peroxidative damage to sperm membranes and increase of intracellular cAMP and cGMP may be involved in these benefits. It is possible that FA may be used for cure of asthenozoospermic infertility.

Antioxidative and chelating activities of phenylpropanoid glycosides from Pedicularis striata

AIM

To study the antioxidative and iron chelating activities of phenylpropanoid glycosides (PPG) isolated from a Chinese herb Pedicularis striata.

METHODS

Antioxidative effects of PPG on lipid peroxidation induced by FeSO4-edetic acid in linoleic acid were measured by thiobarbituric acid method. Chelating activities of PPG for Fe2+ were tested by differential spectrum method.

RESULTS

The reaction rates (A532.min-1) of lipid peroxidation were 0.0046 in the control, 0.0021 in verbascoside group, and 0.0008 in isoverbascoside group. The chelating activity of isoverbascoside was 2-fold stronger than that of verbascoside. Permethyl verbascoside showed neither antioxidative nor chelating activities.

CONCLUSION

The inhibitory effects of PPG with phenolic hydroxy groups on lipid peroxidation are owing to their chelating properties. Under physiological condition PPG-Fe2+ chelates are sufficiently stable. Thus PPG are able to inhibit the Fe(2+)-dependent lipid peroxidation in vivo through chelating Fe2+ and exhibit their therapeutic potential by the same mechanism in vitro.

Possible role of nitric oxide on fertile and asthenozoospermic infertile human sperm functions

The capacity of human sperm fertilization is principally dependent on sperm motility and membrane integrity. Oxygen-derived free radicals, such as superoxide anion, are known to impair sperm motility and membrane integrity by inducing membrane lipid peroxidation (LPO). Nitric oxide (NO), a biologically active free radical, has recently been shown to inactivate superoxide and increase intracellular guanosine-3', 5'-cyclic monophosphate (cGMP). The aim of this study is to investigate the effects of NO on human sperm motility, viability, lipid peroxidation and cGMP in fertile and asthenozoospermic infertile individuals in vitro. Semen samples were obtained from 10 fertile volunteers and 10 asthenozoospermic infertile patients. Washed spermatozoa were incubated at 37 degrees C in Ham's F-10 medium with 0, 25, 50, 100, 200, or 400nM sodium nitroprusside (SNP, Na2 [Fe(CN) 5NO] 2H2O), a nitric oxide releaser. Samples were analyzed for viability, determined by eosin-Y dye exclusion method at 0, 1, 2, 3, 5 and 6 h of incubation; motility, determined by the trans-membrane migration method within 2 h of incubation; LPO determined by malondialdehyde (MDA)-thiobarbituric acid method at 3 h of incubation; and the intracellular cGMP, determined by 125I-cGMP radioimmunoassay at 3 h of incubation. The results showed: in both fertile and infertile samples, viability, trans-membrane migration ratio and the levels of intracellular cGMP in 25-100nM SNP-treated spermatozoa were significantly higher than those in control groups, while MDA contents in treated groups were significantly lower than those in controls. However, when concentrations of SNP increased to 200-400nM, the opposite effects were exhibited. The effects of SNP on these processes were biphasic within 25-400nM. The most effective concentration was 100nM. These data suggested that NO is beneficial to sperm viability and motility in both fertile and infertile individuals, and that reduction of lipid peroxidative damage to sperm membranes and increase of intracellular cGMP may be involved in these benefits.

Promotion of human sperm capacitation by superoxide anion

Capacitation of spermatozoa is an essential procedure for fertilization. Capacitated spermatozoa have an increase in the intracellular cAMP and acrosome reaction (AR) occurs immediately. The effect of exogenous superoxide anion (O2-) on the level of intracellular cAMP and the percentages of both spontaneous AR and lysophosphatidylcholine-induced AR (LPC-AR) were studied using semen samples collected from 10 healthy and fertile volunteers working or studying in Lanzhou Medical College. Spermatozoa were separated by Percoll and incubated at 37 degrees C in Ham's F-10 medium with O2- generation system: xanthine+xanthine oxidase +catalase+diethylenetriaminepentaacetic acid+ sodium formate. The intracellular cAMP was determined by (3H)-cAMP radioimmunoassay at 3 h of incubation, and the percentages of AR and LPC-AR were evaluated by the triple-stain technique at 3.5 h of incubation. The effects of SOD with different concentration were also determined. The results showed:the level of intracellular cAMP (pmol/10(8) spermatozoa) of spermatozoa increased from 14.0 +/- 1.3 to 23.2 +/- 2.5 (P < 0.01), and the percentages of AR and LPC-AR increased from 4.5 +/- 1.1% and 14 +/- 1.9% to 16 +/- 2.0% and 32.5 +/- 1.7%, respectively (P < 0.01 in both comparisons). SOD inhibited these processes concentration dependently. To investigate the source of O2- during in vivo sperm capacitation, female genital tract fluids collected from 6 healthy nonpregnant donors of reproductive age, and seminal plasma, capacitated and noncapacitated spermatozoa from 10 fertile volunteers were investigated by spin trapping method. The results showed: A typical electron paramagnetic resonance spectrum for O2- spin adduct was exhibited only in capacitated spermatozoa but not in vaginal or cervical secretions, uterine and fallopian tubal fluids, nor in seminal plasma and noncapacitated spermatozoa. These results suggested that only capacitated spermatozoa themselves are able to generate O2- which stimulated their capacitation in turn. Furthermore, on the basis of these data, we propose that it may be possible to utilize the inhibitory effect of SOD on sperm capacitation so as to regulate fertilization.

Photosensitization of bilirubin on proliferation and DNA synthesis in ascitic hepatoma cells

AIM

To observe the effects and its mechanism of photosensitization of bilirubin on ascitic hepatoma (Hep A) cells.

METHODS

After the cells were illuminated under the light (1.0 x 10(5) lx) for 10 min, deoxy[3H]thymidine was added for DNA synthesis assay. The cells were dyed with 0.5% trypan blue and were counted.

RESULTS

The cell mortality of illuminated groups were much higher than that of dark groups (P < 0.01). The inhibitions of DNA synthesis of illuminated groups were stronger than that of dark groups (P < 0.01). The cell mortality and inhibition of DNA synthesis of illuminated groups were positively dependent upon the concentrations of bilirubin and illuminating time. No difference of DNA synthesis between room light illumination groups and dark groups (P < 0.05).

CONCLUSION

The photosensitization of bilirubin killed Hep A cells obviously. Bilirubin under room light had no effect on inhibition of DNA synthesis. The photosensitization of bilirubin was closely related to 1O2 and H2O2 and not to OH. and O2-. Bilirubin, the end product of heme catabolism in mammals, is a potentially cytotoxic, lipid soluble waste product that needs to be excreted. However, bilirubin at micromolar concentration in vitro, efficiently scavenges peroxyl radicals. In liposomes, bilirubin suppresses the antioxidation more than alpha-tocopherol, which is regarded as the best antioxidant of lipid peroxidation. Thus bilirubin is a physiological, chain-breaking antioxidant. Bilirubin exhibited antitumor activity and acted as a photosensitizer with four pyrrole rings. Many photosensitizers have been used to treat cancer due to their photosensitization. In this paper, the photosensitization of bilirubin on DNA synthesis in ascitic hepatoma (Hep A) cells and on cell mortality were studied.

Phosphofructo-1-kinase: role of charge neutralization in the active site

Previous studies of Escherichia coli phosphofructo-1-kinase have shown that mutation of Asp 127 lowers kcat by 5 orders of magnitude. As shown here, introduction of a second mutation (R252Q) that neutralizes a positive charge in the active site increases activity of D127S by 100 fold, suggesting that part of the effect of the Asp mutation may be attributed to non-specific charge interactions. This conclusion is supported by the fact that the R252Q mutant shows a pH dependence that is the reverse of the wild type enzyme, whereas the double mutant has a pH dependence that resembles that of wild type enzyme, although somewhat attenuated.

[Photosensitization of dicoumarol on tumor cells and enhancement by sodium diethyldithiocarbamate]

AIM

To study the photosensitization of dicoumarol (Dic) on tumor cells and any effect by sodium diethyldithiocarbamate (DDC).

RESULTS

Dic, 40, 80, 120 mumol.L-1 concentration-dependently inhibited the DNA synthesis (81%-93%) and increased the mortality (50%-70.4%) of ascitic hepatoma (Hep A) cells exposed in light. These 2 indices were changed slightly by Dic alone even in non-illuminating group. DDC enhanced the photosensitization of Dic group.

CONCLUSION

Photosensitization of Dic showed strong antitumor activities against Hep A cells. The mortality of Hep A and inhibition of the DNA synthesis in Dic-DDC-light group significantly stronger than in Dic-light group. Photosensitization of Dic was not due to 1O2 and OH., but closely related to O2.- and H2O2.

Identification of interactions that stabilize the transition state in Escherichia coli phosphofructo-1-kinase

The activity of Escherichia coli phosphofructo-1-kinase depends upon the dissociation of a group with a pK of approximately 6.6. Mutation of the 2 active site residues most likely to be titrated in this range, Asp-127 and Asp-129, lowered activity but produced little change in the pH dependence, suggesting that these residues while important to activity were not responsible for the pH dependence of the enzyme. Alternatively, the pH dependence was thought to correspond to the negative charge on the phosphoryl group being transferred in the reaction. Mutation of Arg-72 to histidine, while lowering the activity substantially, shifted the pH optimum to approximately 6.2 with a secondary plateau on the alkaline limb that was eliminated in the double mutant R72H/R171H. Mutation of Arg-171 alone produced only a small decrease in maximal activity and little change in pH dependence from the wild type enzyme. The data support an associative mechanism with a transition state stabilized by the interaction between the negative charge on the phosphoryl group being transferred and the arginyl residue at position 72 on the enzyme.

Retardation of cell aging by lipid peroxidation. II

Fe2+/vitamin C system was used to stimulate lipid peroxidation in human diploid fibroblasts derived from embryonic lung tissue to study the relationship between lipid peroxidation and cell senescence. The results showed that certain low levels of lipid peroxidation could evidently improve cellular morphology and prolong 2-8 days of cell survival time. All cellular SOD activities of control and treatment groups decreased with cell subculture. However, SOD activities of treatment groups were not higher than that of the control, which indicated that under certain circumstances SOD would not play an important role in retardation of cell aging.

Site-directed mutagenesis of two highly conserved residues near the active site of phosphofructo-1-kinase

Mutations of either of two highly conserved residues near the active site of Escherichia coli phosphofructokinase, Ile-126 or Asn-128, produce no changes in the Km for ATP, relatively small changes in kcat, and a large increase in the Km for fructose 6-P, despite the fact that these residues are not directly involved in substrate binding. A computer graphics analysis of the three-dimensional structure suggests that the mutations effect the orientation of Arg-252, a residue important both for fructose 6-P binding and for catalysis.

[Free radical scavenging and antifatigue activities of Saussurea involucrata polysaccharides]

The polysaccharides of Saussurea involucrata Kar et Kir was first isolated and identified by us. The polysaccharides scavenged superoxide anions by nitroblue tetraazolium colorimetric method with a median scavenging concentration of 22 micrograms.ml-1 and 95% confidence limit was 19.9-24.1 micrograms.ml-1. The polysaccharides inhibited the formation of thiobarbituric acid reaction substance in mouse liver homogenate and its IC50 was 2.3 mg/g fresh liver and 95% confidence limit was 2.05-2.55 mg/g fresh liver. By ip 25 mg.kg-1.d-1 x d in mice, the polysaccharides decreased oxygen consumption by 34.4% and ip same dosage x 6 d, the polysaccharide prolonged swimming time by 1.69-fold.

Inhibition of the autoxidation of linoleic acid by phenylpropanoid glycosides from Pedicularis in micelles

The activities of six phenylpropanoid glycosides as chain-breaking antioxidants have been studied for the autoxidation of linoleic acid in cetyl trimethylammonium bromide (CTAB) micelles at 37 degrees C. Verbascoside, isoverbascoside, echinacoside and pedicularioside A, which possess four phenolic hydroxyl groups, exhibited antioxidant activities, while cistanoside D possessing only two phenolic hydroxyl groups and permethyl verbascoside without phenolic hydroxyl group did not suppress the oxidation appreciably. The ratio of rate constants for inhibition and propagation kinh/kp and stoichiometric factor n were determined.

The mechanism of ATP inhibition of wild type and mutant phosphofructo-1-kinase from Escherichia coli

Escherichia coli 6-phosphofructo-1-kinase was inhibited by high concentrations of ATP at alkaline pH. The mechanism of the inhibition was studied with two mutants generated by site-directed mutagenesis; I126A, with a Km for fructose-6-P that was more than two orders of magnitude higher than that of wild type but with minimal changes in kcat and Km for ATP, and R72H, with little change in substrate half-saturation concentrations but with a kcat that was 300-fold lower that of wild type enzyme. ATP and fructose-6-P interacted in a mutually antagonistic manner; that is ATP decreased the apparent affinity for fructose-6-P and vice versa. The half-saturation concentrations for both substrates, most strikingly fructose-6-P, increased with increasing pH while the kcat increased. Studies with I126A suggested that ATP inhibition was not dependent on a dissociable group with a pK in the alkaline range and that the inhibition was not caused by abortive binding of substrate to the wrong substrate site. Inhibition was not the result of differential affinity of ATP for the R and T states of the enzyme. The low kcat mutant, R72H, did not display ATP inhibition. These data indicate that ATP inhibition results from substrate antagonism coupled with a steady state random mechanism wherein the high rate of catalysis does not permit equilibration of substrates.

Inhibitions of the autoxidation of linoleic acid by flavonoids in micelles

The activities of five flavonoids as chain-breaking antioxidants have been studied for the autoxidation of linoleic acid in cetyl trimethylammonium bromide (CTAB) micelles at 37 degrees C. Flavonols such as quercetin, rutin and morin exhibited antioxidant activities, while two flavanones, naringin and hesperidin, did not suppress the oxidation appreciably. The ratio of rate constants for inhibition and propagation kinh/kp and stoichiometric factor n were determined.

Retardation of cell aging by lipid peroxidation

Different concentrations of Fe2+/vitamin C mixtures were used as initiators of lipid peroxidation in diploid fibroblasts from cultured human embryonic lung. Malondialdehyde (MDA) formation in the cell cultures was correlated directly with the concentrations of Fe2+ and vitamin C. Lipid peroxidation was associated with an increase in life-span, decrease in the population doubling time and increase in cellular DNA synthesis. The effects of lipid peroxidation varied inversely with the MDA level. These data showed that low levels of lipid peroxidation retarded several biological properties of cultured cells that are associated with cell aging.

Scavenging effects of phenylpropanoid glycosides on superoxide and its antioxidation effect

The antioxidative activities of six phenylpropaniod glycosides (PPG) extracted from Pedicularis striata and Pedicularis lasiophrys for inhibiting the lipid peroxidation induced by Fe2+/ascorbic acid in mouse liver microsome may be related to the number and steric position of phenolic hydroxyl groups (PHG) they possess (32.5 mumol.L-1 to 65.0 mumol.L-1). The scavenging effects of PPG for superoxide produced by NBT/PMS/NADH system may be related to both the number of PHG and their conjugated system (16.0 mumol.L-1 to 65.0 mumol.L-1).

[Inhibition of photosensitization of morin on DNA synthesis of ascites hepatoma cells]

Morin (0.012, 0.12, 1.2, 12.0 micrograms.ml-1) significantly inhibited the DNA synthesis of ascitic hepatoma (AH) cells. The inhibition of DNA synthesis and cell mortality was dependent on its concentrations as well as the illumination time. Photosensitization of morin was not due to 1O2 and O2-, but closely related to OH. and H2O2. The mechanism of the inhibition may be attributed to the damage of DNA replication template.

DNA synthesis inhibition of nitroxide radicals on leukemia cells

4-isothiocyanate-2,2,6,6-tetramethyl-piperidine-1-oxyl has the strongest effects on the DNA synthesis and viability of isolated leukemia 7712 cells. This compound is a very potent inhibitor of DNA synthesis with 50% inhibition of cell DNA synthesis occurring at 2.2 micrograms/ml, while the LD50 for white mice is 277 mg/kg. During the concentration of 50 micrograms/ml, the inhibition of DNA synthesis is 99.7%, which is unable to damage the DNA replicate template. The inhibition of this compound, a combination of nitroxide and isothiocyanate, appears to be stronger than that of the sum of the two separate actions. Much more moderate effects are seen for all the other nitroxide radicals. After reducing nitroxide to hydroxylamine, there is no inhibition for DNA synthesis. The free radical mechanism of carcinogenesis and antitumor action has been discussed.

Phenolic compounds and an analog as superoxide anion scavengers and antioxidants

Five phenolic compounds and pyridoxine were studied for their activities as both scavengers of superoxide anions and inhibitors of lipid peroxidation. The superoxide anions were generated in a phenazin methosulfate-NADH system and were assayed by the reduction of nitroblue tetrazolium. The superoxide anion scavenging activities of verbascoside and alizarin yellow R were the strongest, followed by those of caffeic acid and phloridzin; vanillin and pyridoxine exhibited the weakest activity. The concentration values yielding 50% inhibition of lipid peroxidation in mouse liver microsomes were 10(-5) M for verbascoside, 10(-4) M for alizarin yellow R and caffeic acid, and 10(-3) M for phloridzin; vanillin and pyridoxine had almost no antioxidative activity. The inhibition of lipid peroxidation by these individual compounds was much weaker than by butylated hydroxyanisole. The results showed that phenolic compounds and pyridoxine have more than one mechanism of action for free radicals and are able to suppress free radical processes at two stages: the formation of superoxide anions and the production of lipid peroxides.

Flavonoids as superoxide scavengers and antioxidants

The superoxide anions scavenging activity and antioxidation of seven flavonoids--quercetin, rutin, morin, acacetin, hispidulin, hesperidin, and naringin--were studied. The superoxide anions were generated in a phenazin methosulphate-NADH system and were assayed by reduction of nitroblue tetrazolium. The scavenging activity ranked: rutin was the strongest, and quercetin and naringin the second, while morin and hispidulin were very weak. The concentration values yielding 50% inhibition of lipid peroxidation in mouse liver homogenate were in order of 10(-6) M for quercetin, rutin, and morin; and of 10(-5) M for acacetin and hispidulin, while naringin and hesperidin had no antioxidative action. In comparison with the antioxidative and scavenging activities of flavonoids, there are no correlations.

[Mechanism of active oxygen in cytocidal activity of tetrabromofluorescein]

Photosensitization induced by tetrabromofluorescein (eosin, 3.8 mumol/L) in ascites hepatoma cells or in normal kidney cells of mice was found to be significant. The cytocidal activity increased in proportion to the concentration of fluorescein as well as with irradiation time. ESR signals were not detected using a trapping agent, 2,2,6,6-tetramethyltetrahydroxy-piperidine (TMHP) which functions as a singlet oxygen probe. No effect on photosensitization by superoxide dismutase (SOD), NaN3, histidine, mannitol or beta-carotene were observed. However, catalase did decrease photosensitization. These results indicate that cytocidal activity is not related to 1O2, O2-. or OH., but is related to H2O2. The cytocidal activity of tetrabromofluorescein in ascites hepatoma cells is stronger than that in normal kidney cells.

[Effects of complex of 3,6-di-(dimethylamino)-dibenzopyriodonium with praseodymium dicitrate on the syntheses of DNA, RNA, protein, nucleoprotein and ATP of leukemia L 7712 cells in mice]

The incorporations of [3H] thymidine, [3H]uridine and [3H]leucine into DNA, RNA and protein synthesis in leukemia 7712 cells were inhibited by the complex of 3,6-di-(dimethylamino)-dibenzopyriodonium with praseodymium (Pr, rare earth element) dicitrite 34 micrograms/ml for 3-24 h. The degree of inhibition increased in proportion to the incubation time. After being treated with [C17H20N2I]3[Pr(C6H5O7)2] 34 micrograms/ml for 3, 6, 12 and 24 h, the incorporation of [32P]Na2HPO4 into the nucleoprotein of leukemia 7712 cells was inhibited by 49, 57, 65 and 85%, while those into ATP were inhibited by 43, 59, 65 and 83%, respectively. The ID50 of [C17H20N2I]3[Pr(C6H5O7)2] on DNA synthesis in leukemia 7712 cells at 24 h was 22 micrograms/ml. After the complex was removed from the medium entirely, the rate of DNA synthesis decreased with time over 3-12 h. This result indicated that the inhibition mechanism was likely due to damage to the DNA template.