[Efficacy of intratympanic gentamicin and dexamethasone in the treatment of intractable Meniere's disease]

Objective:To investigate the efficacy and safety of low-dose intratympanic gentamicin (ITG) compared with intratympanic dexamethasone (ITD) in patients with intractable Meniere's disease (MD). Method:Seventy patients affected by definite unilateral MD were enrolled. 1 ml of gentamicin sulfate(40 g/L) was buffered with 0.5 ml of sodium bicarbonate to obtain a 6.4 pH solution with 26.7 g/L concentration. Thirty-five patients were treated with the buffered gentamicin solution on every week for 2 times. Thirty-five patients were treated with ITD (5 mg) in the first two days, and then every week for 4 weeks. At 2-year follow-up, mean outcome measurements consisted of control of vertigo attacks, pure tone average (PTA), dizziness handicap inventory and tinnitus handicap inventory.Result:Among 34 cases with complete follow-up data in the ITG group, complete control of vertigo (class A) was achieved in 27 patients and substantial control of vertigo (class B) in 5 patients. Among 32 cases with complete follow-up data in the ITD group, class A and B were achieved in 13 and 6 patients respectively (P< 0.05). There were no statistically significant variations between the two groups in PTA and THI (t= 1.737 and t=－0.197, P> 0.05).Conclusion:Low-dose ITG achieves better outcome than ITD in the control of vertigo attacks in patients suffering from unilateral intractable MD, with a very low incidence of hearing deterioration.

Comparison of Mitochondrial Function in Boar and Bull Spermatozoa Throughout Cryopreservation Based on JC-1 Staining

BACKGROUND

Poor reproductivity hampers the commercialization of cryopreserved boar semen.

OBJECTIVE

This study was to determine the differences in the sperm mitochondrial function between boar and bull semen at different cryopreservation stages.

MATERIALS AND METHODS

Boar and bull fresh, equilibrated, and frozen-thawed spermatozoa were evaluated for mitochondrial function using JC-1 under a fluorescent microscope.

RESULTS

Bull and boar percentage of spermatozoa staining green (PSSG) showed no difference between fresh and equilibrated semen (P> 0.05). However, frozen-thawed bull and boar semen demonstrated significantly higher PSSG (P < 0.01) than fresh and equilibrated semen. Frozen-thawed boar semen represented a significantly higher PSSG (P < 0.01) than bull semen.

CONCLUSION

Negative cryopreservation influence on boar and bull spermatozoa was not significantly produced by pre-freezing procedures, but rather by freezing and thawing. Cryopreservation has more pronounced negative effects on boar than on bull spermatozoa, which partly explains lagged commercialization of frozen boar semen.

[Risk factors for prevalence of folic acid deficiency in Chinese lactating women in 2013]

Objective: The study aimed to assess the folic acid status of lactating women in China and to analyze factors related to folic acid deficiency in these subjects. Methods: The data on lactating women were extracted from the Chinese National Nutrition and Health Surveillance in 2013. By a multi-stage stratified cluster random sampling method, 10 331 lactating women were selected for the study. The lactating women, 0-24 months postpartum, were from 55 sites in 30 provinces of China, excluding the Tibet Autonomous Region. A standard questionnaire was used to obtain general information and dietary intake during the previous one month period was collected using a food frequency questionnaire. A total of 20% of the total number of lactating women were randomly selected to analyze serum folic acid. Finally, 1 894 lactating women, with questionnaire results and serum folic acid data, were included in the study. Serum folic acid concentrations were analyzed using an electro-chemiluminescence immunoassay method. Folic acid deficiency was defined as a serum folic acid level <2 ng/ml. A multiple logistic regression analysis was used to analyze the factors associated with folic acid deficiency in these women. Results: After excluding abnormal values, 1 894 lactating women were included in the study. Based on our findings, the prevalence of folate deficiency was 3.0% (56/1 894) in lactating women in China. The prevalence of folic acid deficiency was 0.3% (1/388), 1.3% (7/550), 6.0% (38/639) and 3.2% (10/317) in larger, medium or small cities, general rural counties and poor rural counties, respectively. The prevalence of folic acid deficiency was 6.3% (17/269) and 2.4% (39/1 623) for minority and Han ethnic groups, respectively, and was 6.3% (52/823) and 0.4% (4/1 071) for subjects in northern and southern areas of China, respectively. Binary unconditionally logistic regression was used to analyze the factors associated with folic acid deficiency in the lactating women. The results showed that, compared with those living in the south and those in the Han ethnic group, those living in the north and belonging to the minority ethnic group had a greater risk of folic acid deficiency, with (OR=3.63, 95% CI: 1.64-8.05) and (OR=5.42, 95% CI: 1.75-16.74), respectively. With each month of age during childhood, the prevalence of folic acid deficiency decreased by 10% (OR=0.90, 95%CI: 0.85-0.96). Compared with low income subjects, those with middle incomes had OR (95%CI) of 0.25 (0.10-0.60) for folic acid deficiency. A lesser intake of cereal was associated with a greater risk of folic acid deficiency in lactating women (OR=3.04, 95%CI: 1.18-7.79). A lesser intake of tubers was a protective factor for folic acid deficiency in lactating women (OR=0.29, 95% CI:0.12-0.70). Conclusion: The folic acid status of Chinese lactating women has, in general, recently improved. However, living in northern areas, during early lactating periods, belonging to an ethnic minority, living in rural areas, having a low income, lower intake of cereal and excessive intake of tubers were risk factors for folic acid deficiency in lactating women. In these women, folic acid intervention should be considered a priority.

Bis(acetylacetonato)-oxidovanadium(IV) and sodium metavanadate inhibit cell proliferation via ROS-induced sustained MAPK/ERK activation but with elevated AKT activity in human pancreatic cancer AsPC-1 cells

In this study, the antiproliferative effect of bis(acetylacetonato)-oxidovanadium(IV) and sodium metavanadate and the underlying mechanisms were investigated in human pancreatic cancer cell line AsPC-1. The results showed that both exhibited an antiproliferative effect through inducing G2/M cell cycle arrest and can also cause elevation of reactive oxygen species (ROS) levels in cells. Moreover, the two vanadium compounds induced the activation of both PI3K/AKT and MAPK/ERK signaling pathways dose- and time-dependently, which could be counteracted with the antioxidant N-acetylcysteine. In the presence of MEK-1 inhibitor, the degradation of Cdc25C, inactivation of Cdc2 and accumulation of p21 were relieved. However, the treatment of AKT inhibitor did not cause any significant effect. Therefore, it demonstrated that the ROS-induced sustained MAPK/ERK activation rather than AKT contributed to vanadium compounds-induced G2/M cell cycle arrest. The current results also exhibited that the two vanadium compounds did not induce a sustained increase of ROS generation, but the level of ROS reached a plateau instead. The results revealed that an intracellular feedback loop may be against the elevated ROS level induced by vanadate or VO(acac)₂, evidenced by the increased GSH content, the unchanged level at the expression of antioxidant enzymes. Therefore, vanadium compounds can be regarded as a novel type of anticancer drugs through the prolonged activation of MAPK/ERK pathway but retained AKT activity. The present results provided a proof-of-concept evidence that vanadium-based compounds may have the potential as both antidiabetic and antipancreatic cancer agents to prevent or treat patients suffering from both diseases.

[Value of videonystagmography and electrocochleography in prognosis prediction of patients with acute low-tone sensorineural hearing loss]

Objective:To predict the prognosis of acute lowtone sensorineural hearing loss（ALHL）by using the videonystagmography(VNG) and electrocochleography(ECochG).Method:A retrospective study was done in 70 patients with ALHL after long-term follow-up. The recurrence rate and rate of progression to definite Meniere 's disease were determined according to the results of VNG and ECochG tests at the onset of the first episode of hearing loss.Result:Twentynine patients（41.4%）experienced recurrent hearing loss and 5 patients（7.1%）developed to Meniere's disease. In patients with an elevated SP/AP ratio and spontaneous nystagmus, the recurrence rate was 81.8%. However, in those with a normal SP/AP ratio and without spontaneous nystagmus, the recurrence rate was 23.3%.There was a statistically significant difference in the progression rate of Meniere's disease between the groups with(15.2%) and without spontaneous nystagmus.Conclusion:It has a certain reference value to predict prognosiswhen spontaneous nystagmus and an elevated SP/AP ratio are detected on initial examination in patients with ALHL.

The gadolinium-based contrast agent Omniscan® promotes in vitro fibroblast survival through in situ precipitation

The current study aims to explore how the gadolinium (Gd)-based contrast agent (GBCA) Omniscan® enhanced cell viability of murine fibroblasts. The results of scanning electron microscopy showed that Omniscan® can precipitate in cell culture media and deposit on cell membranes. Energy-dispersive X-ray analysis and Fourier-transform infrared spectroscopy demonstrated the presence of Gd and phosphates in the agglomerated particles. By filtering the Omniscan®-containing medium through a 220 nm filter, it can be clearly found that the increased cell viability should be mainly attributed to the insoluble species of gadolinium rather than to chelated gadolinium. Moreover, the effects of other gadolinium-based contrast agents, Magnevist® and Dotarem®, were compared with that of Omniscan®. It is noted that the three contrast agents differed in their ability to induce cell viability, which is possibly ascribed to the different chemical stabilities of gadolinium chelates as demonstrated by the attenuation in cell growth upon the addition of excess ligands to the compounds. The results of flow cytometry analysis also showed that Omniscan® can promote cell growth via an increase in the S-phase cell population as evidenced by the elevated levels of cell cycle associated proteins cyclin D, cyclin A and the phosphorylated Rb protein. Furthermore, our results revealed that integrin-mediated signaling may play an important role in both Omniscan® and Magnevist®-enhanced focal adhesion formation since the blockade of integrins decreased the level of ERK phosphorylation induced by the two GBCAs. Taken together, these data suggested that in situ gadolinium phosphate precipitation formation mediated Omniscan®-promoted fibroblast survival, which is similar to that of gadolinium chloride. It was demonstrated that the application of GBCAs with more stable thermodynamic stability may cause less dissociation of the gadolinium ion and thus resulted in less precipitation, finally leading to lower occurrence of nephrogenic systemic fibrosis. The obtained results would also be helpful for the development of safe gadolinium-based contrast agents.

Production of hGFAP-DsRed transgenic Guangxi Bama mini-pigs via somatic cell nuclear transfer

The mini-pig is a useful animal model for human biomedical research due to its physiological similarity to humans and the ease of handling. In order to optimize the efficiency of production of transgenic Bama mini-pigs through somatic cell nuclear transfer (SCNT), we examined the effects of contact inhibition, roscovitine treatment, and serum starvation on the cell cycle synchronization and transgenic cloned embryo development in vivo and in vitro after nuclear transfer. The analysis showed that the rates of G0/G1 stage cells in the contact inhibition (92.11%) and roscovitine treatment groups (89.59%) were significantly higher than in serum starvation group (80.82%). A higher rate of apoptosis was seen in the serum starvation group (14.13%) compared to the contact inhibition and roscovitine treatment groups (6.71 and 2.46% respectively, P < 0.05). There was a significant decrease in blastocyst yield in the serum starvation group (14.19%) compared to the roscovitine treatment and contact inhibition groups (21.31 and 20.32% respectively, P < 0.05). A total of 1070 transgenic cloned embryos derived from the three treatment groups were transferred to surrogate sows; one pregnancy was established and three embryos from the roscovitine treatment group successfully completed gestation. These results indicate that the roscovitine treatment was more effective at synchronizing transgenic kidney cells in Bama mini-pigs and allowed reconstructed embryos to develop to full term.

Broadband tunable InAs/InP quantum dot external-cavity laser emitting around 1.55 μm

We report a broadband tunable external-cavity laser based on InAs/InP quantum dots (QDs) grown by metal-organic vapor phase epitaxy. It is found that high AsH₃ flow during the interruption after QD deposition greatly promotes QD ripening, which improves the optical gain of QD active medium in lower energy states. Combined with anti-reflection/high-reflection facet coatings, a broadly tunable InAs/InP QD external-cavity laser was realized with a tuning range of 140.4 nm across wavelengths from 1436.6 nm to 1577 nm at a maximum output power of 6 mW.

High performance 2150 nm-emitting InAs/InGaAs/InP quantum well lasers grown by metalorganic vapor phase epitaxy

We demonstrate high performance 2150 nm InAs/InGaAs/InP quantum well (QW) lasers grown by metalorganic vapor phase epitaxy. The laser structure consists of two InAs/InGaAs QWs, with a 30 μm-wide ridge waveguide and two cleaved cavity facets. The continuous wave operation at room temperature (RT) is achieved, with an output power of larger than 160 mW per facet and with a low threshold current density of 90.4 A/cm(2) per QW derived for the infinite cavity length. Under pulse injection mode, the maximal peak power per facet is as high as 1.35 W. By varying the cavity length, the lasing wavelength can be tuned in a range from 2142 nm to 2154 nm. Moreover, the highest operating temperature reaches up to 100 °C, and characteristic temperatures are 50 K (T(0)) and 132 K (T(1)) in the temperature range of 20-70 °C, respectively.

The complete mitochondrial genome of Fujian rod gugeon Microphysogobio fukienensis (Nichols) (Cypriniformes, Cyprinidae)

In this study, the complete mitogenome sequence of the Fujian rod gugeon, Microphysogobio fukienensis (Nichols) (Cypriniformes, Cyprinidae, Gobioninae) has been amplified. The mitogenome, consisting of 16,600 bp, had the typical vertebrate mitochondrial gene arrangement, including 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNAs genes and a noncoding control region (CR). CR of 930 bp length is located between tRNA(Pro) and tRNA(Phe). The overall base composition of M. fukienensis is 31.0% for A, 26.0% for C, 26.6% for T and 16.4% for G, with higher AT content of 57.0%. The complete mitogenome may provide rather essential and important DNA molecular data for further phylogenetic analysis for not only congeneric species but also higher different taxa of Cyprinid fishes.

[Community structure of phytoplankton in Haizhou bay and adjacent waters and its relationships with environmental factors]

Based on the data collected from four seasonal surveys in 2011 in Haizhou Bay and adjacent waters, community structure of phytoplankton was studied and their relationships with environmental factors were evaluated by canonical correlation analysis (CCA). A total of 113 phytoplankton species belonging to 3 phyla and 44 genera were collected, among which Bacillariophyta species were the most abundant species, which included 39 genera and 99 species, accounting for 87.6% of total taxa, followed by Pyrrophyta, which included 4 genera and 13 species, accounting for 11.5 percent of total taxa. And the least abundant species were Chrysophyta species, which had only 1 species belonging to 1 genus. Among these dominant species, Coscinodiscus and Chaetoceros were the dominant groups in Bacillariophyta, while Ceratium was the dominant group in Dinophyta, and the dominant species were Meuniera membranacea, Coscinodiscus subtilis var. subtilis, Eucampia zodiacus and Bacillaria paxillifera. There were obvious seasonal variations in the species composition and predominant species. The abundances of phytoplankton in all the stations ranged from 0.08 x 10(5) cells m(-3) to 108.48 x 10(5) cells x m(-3) in Haizhou Bay. The average annual density of phytoplankton was 10.71 x 10(5) cells x m(-3), being the highest in autumn (29.08 x 10(5) cells x m(-3)) and the lowest in summer (1.69 x 10(5) cells x m(-3)). The Shannon index, Pielou index and Margalef index of the phytoplankton community were higher in summer and autumn than in winter and spring. CCA suggested that the main factors affecting the phytoplankton community were sea surface temperature (SST), followed by nutrients (NO(3-)-N, PO4(3-)-P, SiO3(2-)-Si) and dissolved oxygen (DO). The abundances and distribution of some dominant species were closely related with these main factors.

Bis(acetylacetonato)-oxovanadium(iv), bis(maltolato)-oxovanadium(iv) and sodium metavanadate induce antilipolytic effects by regulating hormone-sensitive lipase and perilipin via activation of Akt

The increased plasma free fatty acid levels due to the deregulated lipolysis in adipocytes are considered as one of the major risk factors for developing type II diabetes. Vanadium compounds are well-known for their antidiabetic effects both on glucose and lipid metabolism, but the mechanisms are still not completely understood. The present study suggests a mechanism for how vanadium compounds exert antilipolytic effects. It demonstrates that all the three vanadium compounds, bis(acetylacetonato)-oxovanadium(iv) (VO(acac)2), bis(maltolato)-oxovanadium(iv) (VO(ma)2) and sodium metavanadate (NaVO3), attenuated basal lipolysis in 3T3L1 adipocytes in a dose- (from 100 to 400 μM for VO(acac)2 and VO(ma)2, 1.0 to 4.0 mM for vanadate) and time-dependent (from 0.5 to 4 h) manner using the glycerol release as a marker of lipolysis. In addition, the three compounds inhibited lipolysis to a different extent. Among them, VO(acac)2 (from 100 to 400 μM) exerted the most potent effect and reduced the lipolysis to ∼60-20% of control after 4 h treatment. The antilipolytic effects of vanadium compounds were further evidenced by a decrease of the levels of phosphorylated HSL at Ser660 and phosphorylated perilipin, which were counteracted by inhibitors of PI3K or Akt but not by an MEK inhibitor. This indicates that though both Akt and ERK pathways are activated by the vanadium compounds, only Akt activation contributes to the antilipolytic effect of the vanadium compounds, without the involvement of ERK activation. We previously demonstrated that VO(acac)2 can block cell cycle progression at the G1/S phase via a highly activated ERK signal in human hepatoma HepG2 cells. Together with this study, we show that similar activated pathways may lead to differential biological consequences for cancer cells and adipocytes, indicating that vanadium compounds may be used in the prevention and treatment of both diabetes and cancer.

Chemical, biochemical, and biological behaviors of vanadate and its oligomers

Vanadate is widely used as an inhibitor of protein tyrosine phosphatases (PTPase) and is routinely applied in cell lysis buffers or immunoprecipitations of phosphotyrosyl proteins. Additionally, vanadate has been extensively studied for its antidiabetic and anticancer effects. In most studies, orthovanadate or metavanadate was used as the starting compound, whereas these "vanadate" solutions may contain more or less oligomerized species. Whether and how different species of vanadium compounds formed in the biological media exert specific biological effect is still a mystery. In the present commentary, we focus on the chemical, biochemical, and biological behaviors of vanadate. On the basis of species formation of vanadate in chemical and biological systems, we compared the biological effects and working mechanism of monovanadate with that of its oligomers, especially the decamer. We propose that different oligomers may exert a specific biological effect, which depends on their structures and the context of the cell types, by different modes of action.

Lanthanides inhibit adipogenesis with promotion of cell proliferation in 3T3-L1 preadipocytes

Lanthanides are widely used in various fields for industrial, agricultural and medical purposes. They have also been used in Chinese agriculture either as fertilizers in plant production or as performance-enhancers in animal nutrition for many years. In view of their possible application for growth enhancing purposes and new medical applications, detailed information on how lanthanides influence physiological processes in biological systems is indispensable. In the present work, the effects of lanthanides (LaCl3, CeCl3 and GdCl3) on cell proliferation and adipogenesis in 3T3-L1 preadipocytes were evaluated. The results demonstrate that lanthanides inhibit adipogenesis in 3T3-L1 preadipocytes, evidenced by decreased triglyceride content and expression of C/EBPα and PPARγ. Simultaneously, the results show that lanthanides can promote cell proliferation during the different stages of differentiation. Firstly, prior to the addition of differentiation inducers (MDI), all the three types of lanthanides resulted in a significant increase of cell growth. Secondly, during the mitotic clonal expansion (MCE) process, GdCl3, as a representative compound, is able to promote cell-cycle entry into the S phase and levels of cell cycle-regulating proteins. Third, at the late stage of the terminal differentiation, on day 8, in the presence of GdCl3, cells exhibited higher levels of G1/S regulatory proteins and proliferating cell nuclear antigen (PCNA). In addition, GdCl3 caused stronger sustained ERK activation during the differentiation process of 3T3-L1 cells. The present study demonstrates that lanthanides may modulate lipid metabolism by inhibition of adipocyte differentiation. The sustained activation of the ERK pathway might be responsible for their inhibition of differentiation and a possible link between their pro-proliferative ability and inhibition of the differentiation process is indicated.

Full-term pregnant women have higher lumbar epidural pressure than non-pregnant women: a preliminary report

The objective of this study was to compare the lumbar epidural pressure of full-term pregnant women with that of non-pregnant women. The epidural pressure of 20 full-term pregnant women and 15 non-pregnant women was measured during epidural needle insertion in the lateral position (T0), and at 30-s intervals following insertion (T1-T3), after the patient was turned supine (T4-T6), and after local anaesthetic injection (T7-T9). Results showed that the average epidural pressures following epidural insertion in the lateral position (average of T1-T3), in the supine position (average of T4-T6), and after local anaesthetic injection (average of T7-T9) were all significantly higher in the pregnant women compared with those who were not pregnant (p= 0.0293, 0.0109 and 0.0309, respectively). Epidural pressures increased significantly after women were turned supine (p < 0.001). Average epidural pressures were positive for all time points, T0-T9. It was concluded that the epidural pressure in the pregnant women was higher than in those who were not pregnant, both in the lateral and the supine position.

Integrin-mediated signaling contributes to gadolinium-containing-particle-promoted cell survival and G₁ to S phase cell cycle transition by enhancing focal adhesion formation

We previously reported that Gd-containing particles formed under physiological conditions act as active entities to enhance cell survival and promote S phase entry via activation of both mitogen-activated protein kinase/extracellular-signal-regulated protein kinase (ERK) and phosphatidylinositol 3-kinase/Akt signaling pathways. However, how they transduce the extracellular signal inside the cell remains unclear. The present study demonstrates that Gd-containing particles can alleviate serum-deprivation-induced cell death and promote G₁ to S phase cell cycle progression by enhancing cell adhesion to the extracellular matrix. As an indicator of adhesion, the vinculin distribution was detected by confocal laser scanning microscopy. The control cells exhibited fewer and less typical focal adhesions. After treatment with Gd-containing particles, a large number of vinculin-containing focal adhesions were maintained. In the presence of integrin antagonists, the percentage of S phase entry induced by Gd-containing particles was decreased and the enhancement of cell viability was also attenuated, along with a decrease in both cyclin D expression and ERK phosphorylation. In summary, the present results suggest that the integrin-mediated signaling pathway plays an important role in cell survival and G₁ to S phase transition promoted by Gd-containing particles by enhancing focal adhesion formation. The results presented here provide novel evidence to advance knowledge leading to further understanding of the mechanisms of both cell proliferation and cell survival promoted by Gd and may be helpful for developing effective measures to prevent or treat nephrogenic systemic fibrosis.

Protective effects of melatonin against oxidative stress in flow cytometry-sorted buffalo sperm

Previous reports of the ability of melatonin to scavenge a variety of toxic oxygen and nitrogen-based reactants suggest that melatonin could be an effective antioxidant for protecting sperm. In this study, flow cytometry and laser tweezers Raman spectroscopy were used to evaluate the effect of melatonin on buffalo sperm quality to optimize sperm sex-sorting procedures. In fresh sperm incubated in the presence or absence of melatonin (10(-4)  m) for 1, 24, 48 h or 72 h at 27°C, the mitochondrial activity was significantly higher than in a non-melatonin control (p < 0.05). Also, during the flow-sorting process, sperm in melatonin-supplemented groups had higher (p < 0.05) mitochondrial activity than the control. The intensity of Raman spectra from sperm frozen in media supplemented with melatonin was significantly weaker than that for non-melatonin-treated groups, except for a band at 1302 per cm. Thus, melatonin helps to protect buffalo sperm from reactive oxygen species induced by staining, sorting and freezing and increases semen quality after the freezing-thawing processes. Furthermore, the results indicate the high potential of the laser tweezers Raman spectroscopy technique for rapid, effective and non-invasive assessment of the quality of sperm cells.

Vanadyl bisacetylacetonate induced G1/S cell cycle arrest via high-intensity ERK phosphorylation in HepG2 cells

In recent years the anticancer properties of vanadium compounds have been noticed, but the underlying mechanisms are not well understood. In the present work, we found that vanadyl bisacetylacetonate ([VO(acac)(2)]) blocked cell cycle progression permanently at G1 phase in a dose- and time-dependent manner in HepG2 cells. This was further evidenced by the growth regulatory signals during the G1 stage. After the treatment with [VO(acac)(2)], the level of phosphorylation of retinoblastoma tumor suppressor protein (pRb) and the expressions of cyclin D1, cyclin E and cyclin A were reduced, while the expression of a cyclin-dependent kinase inhibitor p21 was increased dose-dependently. In the meantime, neither O(2)(*-) nor H(2)O(2) level was observed to increase. Interestingly, the levels of phosphorylated extracellular signal-regulated protein kinase (ERK) and Akt were highly activated. After 1-h pretreatment with a lower concentration of MEK inhibitor U0126, the level of phosphorylated pRb was restored, indicating a release of cell cycle arrest. Taken together, we suggested that [VO(acac)(2)]-induced proliferation inhibition was caused by G1/S cell cycle arrest, which resulted from the decreased level of phosphorylated pRb in its active hypophosphorylated form via a highly activated ERK signal in HepG2 cells. The results presented here provided new insight into the development of vanadium compounds as potential anticancer agents.

The permeability and cytotoxicity of insulin-mimetic vanadium compounds

PURPOSE

The aim of this study was to investigate the mechanism of permeation and cytotoxicity of vanadium compounds, [VO(acac)2], [VO(ma)2], and vanadate.

METHODS

Absorptive transport were carried out in Caco-2 monolayers grown on transwell inserts. Vanadium was quantified using inductively coupled plasma atomic emission spectrometry (ICP-AES). The change of Caco-2 cells in the microvilli morphology and F-actin structure was visualized by transmission electron microscopy and confocal laser scanning microscopy.

RESULTS

The three vanadium compounds were taken up by Caco-2 cells via simple passive diffusion. [VO(acac)2] were mainly transcellularly transported and exhibited the highest apparent permeabilty coefficients (8.2 x 10(-6) cm(-1)). The cell accumulation of [VO(acac)2] was found to be greater than that of [VO(ma)2], and vanadate caused much less accumulation than the other two compounds. Vanadium compounds induced intracellular reactive oxygen species, reduced the transepithelial electric resistance, caused morphological change in microvilli, and led to different perturbation of F-actin structure.

CONCLUSIONS

The three compounds exhibited different permeability due to different diffusion process and cellular uptake. The toxicity of vanadium complexes on Caco-2 monolayer involved F-actin-related change of tight junction and impairment of microvilli. The toxicity was also related to elevated intracellular reactive oxygen species (ROS) and their cellular accumulation.

[Progress in the study of mammalian selenoprotein]

Selenium is an essential trace element for animals and humans. Selenium exerts its biological function largely through selenoproteins. Up to now nine selenoproteins' cDNAs have been cloned and sequenced, which are cellular glutathione peroxidase (cGPX), extracellular glutathine peroxidase(eGPX), phospholipid hydroperoxidase glutathione peroxidase(PHGPX), gastrointestinal glutathione peroxidase (GPX-GI), type I iodothyronine 5'-deiodinase (ID I), type 2 iodothyronine 5'-deiodinase(ID II), type III iodothyronine 5-deiodinase(ID III), selenoprotein P (Se-P) and selenoprotein W. In all these selenoproteins Se is incorporated into the protein molecule via the selenocysteinyl-tRNA which recognizes the specific UGA codons in mRNA to insert selenocysteine into the primary structure of selenoproteins.