A cobalt nanoparticles modified ITO electrode (NpCo/ITO) was prepared by casting cobalt nanoparticles onto ITO electrode and the cobalt nanoparticles were synthesized by NaHB4 reduction. The electrochemical behaviors of adriamycin (ADM) on NpCo/ITO were studied. The modified ITO electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In a 0.01 mol L(-1) PBS (pH 8.0) buffer solution, a sensitive reduction peak of ADM was obtained. A linear relationship is held between the peak current and ADM concentration in the range of 1.0 x 10(-8) - 2.0 x 10(-6) mol L(-1) with detection of 5.0 x 10(-9) mol L(-1)- by cyclic voltammetry (CV) response. The reduction process was irreversible with adsorption at the NpCo/ITO electrode. The modified electrode showed an excellent electrocatalytic activity for the ADM electrochemical reduction.
Antineoplastic Agents ; chemistry ; pharmacology ; Clinical Laboratory Techniques ; Cobalt ; chemistry ; Doxorubicin ; chemistry ; pharmacology ; Electrochemistry ; Electrodes ; trends ; Nanoparticles ; chemistry

OBJECTIVETo analyze the differential proteomics in human umbilical cord mesenchymal stem cells (MSC) induced by chemical hypoxia-mimetic agent cobalt chloride (CoCl(2)) by two-dimensional gel electrophoresis (2-DE) and mass-spectrometry.

METHODS2-DE was performed to separate proteins from treated and untreated human umbilical cord MSC with CoCl(2). 2-DE images were analyzed by ImageMaster 2D Platinum software 6.0. The differential expressed proteins was identified by MALDI-TOF-MS. The differential proteins were classified based on their functions.

RESULTS2-DE reference patterns of CoCl(2) treated human umbilical cord MSC were established. A total of twenty-six differential proteins were identified, of them eleven proteins were up-regulated and fifteen down-regulated. Their biological functions involved in carbohydrate metabolism, protein metabolism and modification, lipid metabolism, coenzyme and prosthetic group metabolism, cell cycle, immunity and defense, cell structure and motility, signal transduction, protein targeting and localization, neuronal activities, muscle contraction, etc. Peroxiredoxin1 (Prdx) was down-regulated, whereas alpha-enolase (ENO1) and vesicle amine transport protein 1 homolog (VAT1) up-regulated.

CONCLUSIONThe effects of hypoxia on human umbilical cord MSC were participated by multiple proteins and involved in multiple functional pathways.

Cobalt ; pharmacology ; Humans ; Mesenchymal Stromal Cells ; drug effects ; metabolism ; Proteome ; analysis ; Proteomics ; Umbilical Cord ; cytology ; drug effects

To explore the effect of propofol on human cardiac AC16 cells under CoCl2-induced hypoxic injury and the possible mechanisms.
 Methods: Human AC16 cardiomyocytes were treated with cobalt chloride (CoCl2) to mimic hypoxic condition in cultured cardiomyocytes. The AC16 cells were divided into 3 groups: a control group, a CoCl2 hypoxia group (CoCl2 group), and a propofol+CoCl2 group (propofol+ CoCl2 group). The cell viability was assessed by cell counting kit-8 (CCK-8). Cell apoptosis ratio (AR) and the mitochondrial membrane potential (Δψm) were detected by flow cytometry. The reactive oxygen species (ROS) production in AC16 cells were determined with the ROS-sensitive fluorescent probe. Meanwhile, total intracellular levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in AC16 cells were detected with commercially available kits. Western blot was used to evaluate the activation of c-Jun N-terminal kinase (JNK) and p38 signaling pathways.
 Results: 1) Compared with the control group, AC16 cell viability was decreased significantly in the CoCl2 group following the treatment with 500 μmol/L CoCl2 (P<0.01); 2) Compared with the control group, AR value in AC16 cells was increased significantly in the CoCl2 group, while Δψm was decreased significantly (all P<0.01). Compared with the CoCl2 group, AR value in AC16 cells was decreased significantly in the propofol+CoCl2 group, while Δψm was increased significantly (both P<0.05); 3) Compared with the control group, the levels of ROS and MDA were increased significantly, and the level of SOD was significantly decreased in the CoCl2 group (all P<0.01). Compared with the CoCl2 group, the ROS and MDA levels in the propofol+CoCl2 group were increased significantly and the SOD levels were decreased significantly (all P<0.05); 4) Compared with the control group, the phosphorylation levels of JNK and p38 were increased significantly (both P<0.05) in the CoCl2 group. Compared with the CoCl2 group, the phosphorylation levels of JNK and p38 were decreased significantly in the propofol+CoCl2 group (both P<0.05).
 Conclusion: The pretreatment with propofol may protect human cardiac AC16 cells from the chemical hypoxia-induced injury through regulation of JNK and p38 signaling pathways.
Apoptosis ; Cell Hypoxia ; Cell Line ; Cell Survival ; Cobalt ; pharmacology ; Humans ; Hypoxia ; JNK Mitogen-Activated Protein Kinases ; Propofol ; Reactive Oxygen Species

OBJECTIVEA series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes.

METHODSSchiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2'-Hydroxy)benzylideneaminonaphthothiazole was converted to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method.

RESULTSAll the compounds moderately inhibited the growth of Gram positive and Gram negative bacteria. In the present study among all Schiff bases 2-(2'-hydroxy)benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu(II) metal complex was found to be most potent.

CONCLUSIONThe results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases.

Amines ; chemical synthesis ; pharmacology ; Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Cobalt ; Copper ; Nickel ; Schiff Bases ; Structure-Activity Relationship ; Thiazoles ; chemical synthesis ; pharmacology

Apoptosis can be caused by hypoxia, a major factor during ischemic injury, in cardiomyocytes. However, the regulatory mechanisms underlying hypoxia-induced cardiomyocyte apoptosis have not yet been fully understood. E2F6, an identified E2F family member, has been demonstrated to repress DNA damage-induced apoptosis in our recent study. However, it is unclear whether E2F6 is involved in hypoxia-induced apoptosis. In this study, we determined the expression property of E2F6 during hypoxia-induced apoptosis in H9c2 cells, a rat ventricular myoblast cell line. The results showed that physical hypoxia and chemical hypoxia-mimetic agents desferrioxamine (DFO) and cobalt chloride (CoCl(2)) induced apoptosis in H9c2 cells. Physical hypoxia- and CoCl(2)-induced apoptosis was accompanied with a downregulation of endogenous E2F6 mRNA expression, but not protein expression. DFO treatment resulted in a significant downregulation of both mRNA and protein expressions of endogenous E2F6. These results suggest that E2F6 may be involved in DFO-induced apoptosis, while it is less sensitive in physical hypoxia- and CoCl(2)-induced apoptosis in H9c2 cells. In addition, the apoptosis induced by DFO may share different pathways from that induced by physical hypoxia and CoCl(2).
Animals ; Apoptosis ; Cell Hypoxia ; Cell Line ; Cobalt ; pharmacology ; Deferoxamine ; pharmacology ; Down-Regulation ; E2F6 Transcription Factor ; metabolism ; Myocytes, Cardiac ; cytology ; metabolism ; Rats

This study was aimed to investigate the effect of genistein (gen) on the expression of hypoxia inducible factor-1alpha (HIF-1alpha) induced by cobalt chloride (CoCl(2)) in human leukemia cell line K562. The hypoxia condition was simulated by CoCl(2); the dose- and time-effect groups were prepared as follows: the former were exposed to 0, 50, 100 and 150 micromol/L of CoCl(2) for 72 hours, the latter were detected at 0, 24, 48 and 72 hours while treated with CoCl(2) 100 micromol/L. The gen-treated samples were divided into five groups: (1) normal control; (2) CoCl(2) 150 micromol/L; (3) CoCl(2) 150 micromol/L + gen 50 micromol/L; (4) CoCl(2) 150 micromol/L + gen 100 micromol/L; (5) CoCl(2) 150 micromol/L + gen 200 micromol/L. The HIF-1alpha mRNA and protein were detected by RT-PCR and Western blot respectively. The results indicated that the expression of HIF-1alpha protein in K562 cells induced by CoCl(2) increased in dose-and time-dependent manner (p<0.01), while the expression of HIF-1alpha mRNA in K562 cell remained the similar level (p>0.05). Gen significantly inhibited the expression of HIF-1alpha protein induced by CoCl(2) in dose-dependent manner (p<0.01) while the HIF-1alpha mRNA expression was not affected by treatment of gen (p>0.05). It is concluded that CoCl(2) dose- and time-dependently induced the HIF-1alpha protein expression; HIF-1alpha mRNA was constantly expressed regardless of normoxic conditions or in the presence of cobalt ion under normoxic conditions. Gen can inhibit HIF-1alpha expression in K562 cell induced by CoCl(2) at level of protein, but not mRNA.
Cobalt ; pharmacology ; Down-Regulation ; Genistein ; pharmacology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; K562 Cells ; RNA, Messenger ; genetics ; metabolism

OBJECTIVETo explore the expression of integrin-linked kinase (ILK) in fibroblasts (Fbs) of scar induced by cobalt chloride (CoCl2) and its effect on cell proliferation.

METHODSThe human hypertrophic scar Fbs of seven patients were isolated and cultured in vitro. Cells from the 5th to the 6th passages were used in the experiment. Six bottles of Fbs were obtained from each of the seven patients, and they were respectively cultured with DMEM nutrient solution containing CoCl2 in the concentration of 0, 50, 100, 150, 200, and 250 µmol/L for 24 h. The expression of ILK mRNA was determined with real-time fluorescence quantitative PCR. Fbs were stimulated by CoCl2 in the most suitable concentration (100 µmol/L) and the protein expression of ILK was determined 0, 1, 2, 4, 12, and 24 h after the stimulation. Then the Fbs were divided into control group (cultured with nutrient solution), negative control group (transfected with con-siRNA), and ILK siRNA group (transfected with ILK siRNA). They were cultured with nutrient solution containing CoCl2 in different concentrations 24 h after transfection, with 4 wells for each concentration in each group. The cell proliferation was detected by XTT assay. Data were processed with one-way analysis of variance (ANOVA) and ANOVA for repeated measurement, and LSD method was used in multiple comparisons.

RESULTSThe expression level of ILK mRNA was highest in Fbs cultured with 100 µmol/L CoCl2 for 24 h, with significant difference compared with those of Fbs cultured with other concentrations of CoCl2 (F = 50.958, P < 0.001). The expression of ILK protein in Fbs cultured with 100 µmol/L CoCl2 for 1 h (0.243 ± 0.009) was lower than that cultured for 0 h (0.387 ± 0.017), and it started to increase from 2 h (0.361 ± 0.010), and exaggerated at 4 h (0.584 ± 0.028), 12 h (0.730 ± 0.029), and 24 h (0.785 ± 0.031). The expression levels of ILK protein at 1, 4, 12, 24 h were statistically different from that at 0 h (P values all below 0.05). XTT showed that cell proliferation level was highest in control group when cultured with 100 µmol/L CoCl2 (F = 488.026, P < 0.001), which decreased from 150 µmol/L. The cell proliferation level in control group cultured with 250 µmol/L CoCl2 was significantly lower than that with 0 µmol/L (P values all below 0.05). There was no significant change in cell proliferation in ILK siRNA group among different concentrations of CoCl2 (F = 2.542, P = 0.056). The cell proliferation level in ILK siRNA group was significantly lower than that in control group and negative control group (F = 2519.542, P < 0.001).

CONCLUSIONSILK may be a key protein in response of hypoxia in Fbs. The mild hypoxia can stimulate the expression of ILK and promote the proliferation of Fbs, while severe hypoxia can reduce the expression of ILK and inhibit cell proliferation.

Cell Proliferation ; drug effects ; Cells, Cultured ; Cicatrix ; metabolism ; pathology ; Cobalt ; pharmacology ; Fibroblasts ; drug effects ; metabolism ; pathology ; Humans ; Protein-Serine-Threonine Kinases ; metabolism

OBJECTIVETo explore the effects of hypoxia on the proliferation of human leukemia HL-60 cells and the cellular expression of hypoxia inducible factor-1α (HIF-1α).

METHODSHuman acute myeloid leukemia HL-60 cells with exponential growth in routine culture were exposed to 50, 200, 400, 800 µmol/L CoCl(2) to mimic hypoxic conditions. At 24, 48, and 72 h, the cells were collected for morphological observation, MTT assay, and real-time quantitative PCR for HIF-1α mRNA expression.

RESULTSCompared with the cells without CoCl(2) treatment, the cells with CoCl(2) exposure exhibited obvious morphological changes and a significant growth inhibition which increased with CoCl(2)concentration and exposure time. At low concentrations (50-200 µmol/L), CoCl(2) treatment caused a dose- and time-dependent enhancement of HIF-1α expression in HL-60 cells.

CONCLUSIONHypoxia mimicked by CoCl(2) exposure significantly inhibits the proliferation of HL-60 cells, and at the non-toxic doses, CoCl(2) dose- and time-dependently increases the expression of HIF-1α. The mimicked hypoxic conditions do not cause differentiation of HL-60 cells.

Cell Hypoxia ; Cell Proliferation ; Cobalt ; pharmacology ; HL-60 Cells ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism

OBJECTIVETo investigate the effects of hypoxia induced by cobalt chloride on the expression and the activity of matrix metalloproteinase-2 (MMP-2) in rat hepatic stellate cells (HSC-T6) and to clarify the possible mechanisms.

METHODSHSC-T6 cell line was grown in Dulbecco's modified Eagle medium with 10% fetal calf serum at 37 degrees C and 5% CO2. When reaching confluence, the cells were incubated with serum-free medium in the presence of cobalt chloride (0, 50, 100, 200 micromol/L) for six hours, and then the supernatant and the cells were harvested. The expression of the MMP-2 mRNA and HIF-1alpha protein in HSC-T6 cells was detected using RT-PCR and Western blot respectively. The activity of the MMP-2 in the supernatant was detected by zymography. The binding reaction between HIF-1a protein and MMP-2 gene sequence was investigated by electrophoresis mobility shift assay.

RESULTSWhen the concentration of CoCl2 increased from 0 micromol/L to 200 micromol/L, the expressions of MMP-2 mRNA (the rate of light density) were increased from 0.53+0.12 to 1.57+0.11 and the differences among these four groups were significant (F=34.21). The activity of MMP-2 (the value of light density*band area) decreased gradually from 84.49+5.38 to 53.70+3.42, and the differences among these four groups were also significant (F=29.54). The expressions of HIF-1a were increased gradually with the increase of the CoCl2 concentration. The shift band in the lane of the nuclear protein extraction and the MMP-2 probe containing hypoxia response element showed delays when compared with the lane of the sole probe, and the binding was partially abolished when competing sense oligonucleotides were used.

CONCLUSIONSOur results suggest that chemical hypoxia can up-regulate the expression of MMP-2 mRNA and decrease the activity of the enzyme. HIF-1alpha may play a part in the regulation of MMP-2 transcription under hypoxic conditions.

Animals ; Cell Hypoxia ; Cell Line ; Cobalt ; pharmacology ; Hepatic Stellate Cells ; enzymology ; Hypoxia ; metabolism ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Matrix Metalloproteinase 2 ; metabolism ; RNA, Messenger ; genetics ; Rats

AIMTo study effect of CoCl2 pretreatment on the voltage-gated Na+ and K+ currents of the rat hippocampal neurons after acute hypoxia.

METHODSPrimarily cultured hippocampal neurons were divided into CoCl2 pretreated and non-pretreated groups. Patch clamp whole cell recording technique was used to examine Na+ and K+ currents of the hippocampal neurons.

RESULTSAfter acute hypoxia, I(Na) and I(K) of the hippocampal neurons were significantly decreased and the threshold of I(Na) was right-shifted. Pretreatment of the neurons with CoCl2 inhibited the reduction of I(Na) and I(K).

CONCLUSIONCcCl2 pretreatment alleviates the acute hypoxia-induced changes of I(Na) and I(K), which may be one of the mechanisms for the protective effect of CoCl2 on neurons.

Animals ; Animals, Newborn ; Cell Hypoxia ; Cobalt ; pharmacology ; Hippocampus ; cytology ; physiopathology ; Neurons ; drug effects ; Patch-Clamp Techniques ; Potassium Channels ; metabolism ; Rats ; Rats, Wistar ; Sodium Channels ; metabolism