Recent anthropogenic curtailing of Yellow River runoff and sediment load is unprecedented over the past 500 y.

The Yellow River (YR) is the fifth-longest and the most sediment-laden river in the world. Frequent historical YR flooding events, however, have resulted in tremendous loss of life and property, whereas in recent decades YR runoff and sediment load have fallen sharply. To put these recent changes in a longer-term context, we reconstructed natural runoff for the middle reach of the YR back to 1492 CE using a network of 31 moisture-sensitive tree-ring width chronologies. Prior to anthropogenic interference that started in the 1960s, the lowest natural runoff over the past 500 y occurred during 1926 to 1932 CE, a drought period that can serve as a benchmark for future planning of YR water allocation. Since the late 1980s, the low observed YR runoff has exceeded the natural range of runoff variability, a consequence of the combination of decreasing precipitation and increasing water consumption by direct and indirect human activities, particularly agricultural irrigation. This reduced runoff has resulted in an estimated 58% reduction of the sediment load in the upper reach of the YR and 29% reduction in the middle reach.

Semiconductor Optical Amplifier (SOA)-Driven Reservoir Computing for Dense Wavelength-Division Multiplexing (DWDM) Signal Compensation.

Optical signal processing (OSP) technology is a crucial part of the optical switching node in the modern optical-fiber communication system, especially when advanced modulation formats, e.g., quadrature amplitude modulation (QAM), are applied. However, the conventional on-off keying (OOK) signal is still widely used in access or metro transmission systems, which leads to the compatibility requirement of OSP for incoherent and coherent signals. In this paper, we propose a reservoir computing (RC)-OSP scheme based on nonlinear mapping behavior through a semiconductor optical amplifier (SOA) to deal with the non-return-to-zero (NRZ) signals and the differential quadrature phase-shift keying (DQPSK) signals in the nonlinear dense wavelength-division multiplexing (DWDM) channel. We optimized the key parameters of SOA-based RC to improve compensation performance. Based on the simulation investigation, we observed a significant improvement in signal quality over 10 dB compared to the distorted signals on each DWDM channel for both the NRZ and DQPSK transmission cases. The compatible OSP achieved by the proposed SOA-based RC could be a potential application of the optical switching node in the complex optical fiber communication system, where incoherent and coherent signals meet.

Relationship Between SLC22A1 and SLC22A4 Gene Polymorphisms and Risk of Type 2 Diabetes in Chinese Han Population.

BACKGROUND: This study was to investigate the relationship between SLC22A1 and SLC22A4 gene polymorphisms and genetic susceptibility to type 2 diabetes in Chinese Han population. METHODS: The research group comprised 110 Chinese Han patients with type 2 diabetes, and the control group included 110 healthy volunteers. The polymorphisms of SLC22A1 gene rs628031 and rs2282143 loci and SLC22A4 gene rs2073838 and rs272893 loci were detected in the two groups. RESULTS: Statistically significant differences were identified in the genotype distributions of SLC22A1 gene rs628031 and rs2282143 loci between the two groups (p < 0.05). The A allele frequency of SLC22A1 gene rs628031 locus and the T allele frequency of rs2282143 locus were higher in the research group than in the control group (p < 0.05). The genotype distributions of rs272893 locus showed a significant difference between the two groups (p < 0.05), but not SLC22A4 gene rs2073838 locus (p > 0.05). CONCLUSIONS: The polymorphisms of SLC22A1 gene rs628031 and rs2282143 loci and SLC22A4 gene rs272893 locus of patients with type 2 diabetes indicated a significant difference between the two groups, suggesting that these genetic locus mutations increase the risk of type 2 diabetes in Chinese Han patients.

25-Hydroxycholesterol impairs endothelial function and vasodilation by uncoupling and inhibiting endothelial nitric oxide synthase.

Endothelial dysfunction is a key early step in atherosclerosis. 25-Hydroxycholesterol (25-OHC) is found in atherosclerotic lesions. However, whether 25-OHC promotes atherosclerosis is unclear. Here, we hypothesized that 25-OHC, a proinflammatory lipid, can impair endothelial function, which may play an important role in atherosclerosis. Bovine aortic endothelial cells were incubated with 25-OHC. Endothelial cell proliferation, migration, and tube formation were measured. Nitric oxide (NO) production and superoxide anion generation were determined. The expression and phosphorylation of endothelial NO synthase (eNOS) and Akt as well as the association of eNOS and heat shock protein (HSP)90 were detected by immunoblot analysis and immunoprecipitation. Endothelial cell apoptosis was monitored by TUNEL staining and caspase-3 activity, and expression of Bcl-2, Bax, cleaved caspase-9, and cleaved caspase-3 were detected by immunoblot analysis. Finally, aortic rings from Sprague-Dawley rats were isolated and treated with 25-OHC, and endothelium-dependent vasodilation was evaluated. 25-OHC significantly inhibited endothelial cell proliferation, migration, and tube formation. 25-OHC markedly decreased NO production and increased superoxide anion generation. 25-OHC reduced the phosphorylation of Akt and eNOS and the association of eNOS and HSP90. 25-OHC also enhanced endothelial cell apoptosis by decreasing Bcl-2 expression and increasing cleaved caspase-9 and cleaved caspase-3 expressions as well as caspase-3 activity. 25-OHC impaired endothelium-dependent vasodilation. These data demonstrated that 25-OHC could impair endothelial function by uncoupling and inhibiting eNOS activity as well as by inducing endothelial cell apoptosis. Our findings indicate that 25-OHC may play an important role in regulating atherosclerosis.

Prokaryotic expression of woodchuck cytotoxic T lymphocyte antigen 4 (wCTLA-4) and preparation of polyclonal antibody to wCTLA-4.

Cytotoxic T lymphocyte antigen 4 (CTLA-4) is an inhibitory T cell receptor predominately expressed on activated T cells and plays an important role in regulation of specific T cell responses to viral infection. The woodchuck model is an informative animal model for hepatitis B virus (HBV) infection. In this study, the extracellular region of woodchuck CTLA-4 (wCTLA-4) was cloned and the fusion protein of GST-wCTLA-4 was expressed and purified. Polyclonal antibody against GST-wCTLA-4 (anti-GST-wCTLA-4) was prepared. The full length wCTLA-4 protein expressed in transfected baby hamster kidney cells was detected by anti-GST-wCTLA-4 in western blot analysis and immunofluorescence staining. Anti-GST-wCTLA-4 provides a useful tool to study the role of CTLA-4 in T-cell response in the woodchuck model. Further, the blocking of CTLA-4 with anti-GST-wCTLA-4, as a novel therapy approach for chronic hepatitis B virus infection, could be studied in woodchuck model now.

Reduced antigenicity of naturally occurring hepatitis B surface antigen variants with substitutions at the amino acid residue 126.

BACKGROUND: Substitutions at amino acid residue 126 of hepatitis B surface antigen (HBsAg) occur frequently in hepatitis B virus (HBV) isolates from patients with chronic HBV infection. These substitutions occur naturally, but their significance for viral persistence is unclear and requires further investigation. METHODS: We amplified coding regions of HBsAg by PCR using sera from 1 patient chronically infected with HBV. Three representative clones of HBsAg with amino acid residues 126Ile (I), 126Thr (T) and 126Ser (S) were selected from sequenced clones. HBsAg 126Ala (A) mutants of subtype C/adr and D/adw were generated by site-directed mutagenesis. The HBsAg expression vectors were constructed and transiently transfected into HepG2 cells. The binding reactivity of HBsAg to anti-HBs antibodies was tested by chemiluminescent microparticle immunoassay and by immunofluorescence staining with polyclonal and monoclonal anti-HBs antibodies. RESULTS: Diverse HBsAg variants with substitutions at amino acid residue 126 co-existed in a chronically infected HBV patient. HBsAg with the substitution 126S showed a significantly low antigenicity, while the binding reactivity to anti-HBs of other HBsAg with 126I, 126T and 126A were comparable. CONCLUSION: HBsAg with the 126S substitution has a reduced antigenicity, which may contribute to immune escape in chronic HBV infection.

FOXM1 contributes to taxane resistance by regulating UHRF1-controlled cancer cell stemness.

Therapy-induced expansion of cancer stem cells (CSCs) has been identified as one of the most critical factors contributing to therapeutic resistance, but the mechanisms of this adaptation are not fully understood. UHRF1 is a key epigenetic regulator responsible for therapeutic resistance, and controls the self-renewal of stem cells. In the present study, taxane-resistant cancer cells were established and stem-like cancer cells were expanded. UHRF1 was overexpressed in the taxane-resistant cancer cells, which maintained CSC characteristics. UHRF1 depletion overcame taxane resistance in vitro and in vivo. Additionally, FOXM1 has been reported to play a role in therapeutic resistance and the self-renewal of CSCs. FOXM1 and UHRF1 are highly correlated in prostate cancer tissues and cells, FOXM1 regulates CSCs by regulating uhrf1 gene transcription in an E2F-independent manner, and FOXM1 protein directly binds to the FKH motifs at the uhrf1 gene promoter. This present study clarified a novel mechanism by which FOXM1 controls CSCs and taxane resistance through a UHRF1-mediated signaling pathway, and validated FOXM1 and UHRF1 as two potential therapeutic targets to overcome taxane resistance.

Cotransplantation of Mesenchymal Stem Cells and Immature Dendritic Cells Potentiates the Blood Glucose Control of Islet Allografts.

BACKGROUND: Transplantation of islets is a promising alternative to treat type 1 diabetes (T1D), but graft rejection is the major obstacle to its application in clinical practice. We evaluated the effects of mesenchymal stem cells (MSCs) and immature dendritic cells (imDCs) on islet transplantation in diabetic model. METHODS: The streptozotocin T1D model was established in BABL/c mice. Rat islets were isolated and identified with dithizone (DTZ) staining. MSCs and imDCs were isolated from bone marrow of syngenic mice. Islets, alone or along with MSCs and/or imDCs, were transplanted to the left kidney capsule of diabetic mice. The blood glucose levels and glycosylated hemoglobin levels after transplantation were monitored. RESULTS: Cotransplantation significantly decreased blood glucose and glycosylated hemoglobin levels in the diabetes mice. Transplantation of 200 islets + 2 × 105 MSCs + 2 × 105 imDCs could not only restore normal blood glucose levels, but also significantly prolong graft survival for 12.6 ± 3.48 days. CONCLUSIONS: Cotransplantation of allogenic islets with imDCs and/or MSCs can significantly promote graft survival, reverse hyperglycemia, and effectively control the glycosylated hemoglobin levels.

High Expression of the Newly Found Long Noncoding RNA Z38 Promotes Cell Proliferation and Oncogenic Activity in Breast Cancer.

The aberrant expression of long noncoding RNAs (lncRNAs) has great impacts on cancer origination and progression. In the current study, a newly found lncRNA Z38, which was identified through combining experiments of suppression subtractive hybridization (SSH) and reverse dot-blotting, was found to have high expression in breast cancer. More importantly, inhibiting Z38 expression by gene silencing greatly suppressed breast cancer cell proliferation and tumorigenesis, and treatment with Z38 siRNAs significantly induced cell apoptosis and inhibited tumor growth. In conclusion, the newly found lncRNA Z38, which plays important roles in breast cancer, may act as a candidate biomarker and therapeutic target in carcinomas.

Up-regulation and profibrotic role of osteopontin in human idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal disorder characterized by fibroproliferation and excessive accumulation of extracellular matrix in the lung. METHODS AND FINDINGS: Using oligonucleotide arrays, we identified osteopontin as one of the genes that significantly distinguishes IPF from normal lungs. Osteopontin was localized to alveolar epithelial cells in IPF lungs and was also significantly elevated in bronchoalveolar lavage from IPF patients. To study the fibrosis-relevant effects of osteopontin we stimulated primary human lung fibroblasts and alveolar epithelial cells (A549) with recombinant osteopontin. Osteopontin induced a significant increase of migration and proliferation in both fibroblasts and epithelial cells. Epithelial growth was inhibited by the pentapeptide Gly-Arg-Gly-Asp-Ser (GRGDS) and antibody to CD44, while fibroproliferation was inhibited by GRGDS and antibody to alphavbeta3 integrin. Fibroblast and epithelial cell migration were inhibited by GRGDS, anti-CD44, and anti-alphavbeta3. In fibroblasts, osteopontin up-regulated tissue inhibitor of metalloprotease-1 and type I collagen, and down-regulated matrix metalloprotease-1 (MMP-1) expression, while in A549 cells it caused up-regulation of MMP-7. In human IPF lungs, osteopontin colocalized with MMP-7 in alveolar epithelial cells, and application of weakest link statistical models to microarray data suggested a significant interaction between osteopontin and MMP-7. CONCLUSIONS: Our results provide a potential mechanism by which osteopontin secreted from the alveolar epithelium may exert a profibrotic effect in IPF lungs and highlight osteopontin as a potential target for therapeutic intervention in this incurable disease.

Cardiomyocytes overexpressing TNF-alpha attract migration of embryonic stem cells via activation of p38 and c-Jun amino-terminal kinase.

Tumor necrosis factor-alpha (TNF-alpha) plays an important role in the pathogenesis of myocardial infarction. Stem cells are able to regenerate infarcted myocardium. This study investigated whether TNF-alpha was able to induce migration of embryonic stem cells (ESCs) in vitro. We used a Transwell assay in which neonatal rat cardiomyocytes, with or without transfection of TNF-alpha cDNA, were plated in the lower compartments and mouse ESCs tagged with green fluorescent protein were added to the upper compartments. TNF-alpha level was significantly increased in the medium of the lower compartments seeded with TNF-alpha-transfected cardiomyocytes. Compared with the controls, overexpression of TNF-alpha significantly enhanced migration of ESCs to the lower compartments. This enhancement was attenuated by preincubation of ESCs with the antibody against the type II TNF-alpha receptor (TNF-RII), but not by the antibody against the type I TNF-alpha receptor (TNF-RI). Western blot analysis showed that the phosphorylated protein levels of p38 and c-Jun amino-terminal kinase (JNK) were significantly increased in TNF-alpha-treated ESCs. Inhibition of the activity of p38 or JNK significantly attenuated TNF-alpha-induced ESC migration. Our data demonstrate that excessive TNF-alpha stimulates TNF-RII and enhances migration of ESCs in vitro. Activation of p38 and JNK is required for TNF-alpha-enhanced ESC migration.

Embryonic stem cells cultured in biodegradable scaffold repair infarcted myocardium in mice.

Our previous findings demonstrated that directly injecting embryonic stem cells (ESCs) into ischemic region of the heart improved cardiac function in animals with experimental myocardial infarction (MI). Tissue engineering with stem cells may provide tissue creation and repair. This study was designed to investigate the effectiveness of grafting of ESC-seeded biodegradable patch on infarcted heart. MI in mice was induced by ligation of the left coronary artery. Mouse ESCs were seeded on polyglycolic-acid (PGA) material patches. Three days after culture, an ESC-seeded patch was transplanted on the surface of ischemic and peri-ischemic myocardium. Eight weeks after MI operation and patch transplantation, hemodynamics and cardiac function were evaluated in four (sham-operated, MI, MI + cell-free patch, and MI + ESC-patch) groups of mice. The blood pressure and left ventricular function were significantly reduced in the MI animals. Compared with MI alone and MI + cell-free patch groups, the animals received MI + ESC-seeded patches significantly improved blood pressure and ventricular function. The survival rate of the MI mice grafted with MI + ESC-seeded patches was markedly higher than that in MI alone or MI + cell-free patch animals. GFP-positive tissue was detected in infarcted area with grafting of ESC-seeded patch, which suggests the survivors of ESCs and possible myocardial regeneration. Our data demonstrate that grafting of ESC-seeded bioabsorbable patch can repair infarcted myocardium and improve cardiac function in MI mice. This novel approach of combining stem cells and biodegradable materials may provide a therapeutic modality for repairing injured heart.

Transcription factor cyclic adenosine monophosphate responsive element binding protein negatively regulates tumor necrosis factor alpha-induced protein 1 expression.

Tumor necrosis factor alpha (TNFα)-induced protein 1 (TNFAIP1) was originally identified as a protein involved in DNA replication, DNA damage repair, apoptosis and the progression of certain diseases, such as Alzheimer's disease. In the present study, forskolin, a stimulant of cyclic adenosine monophosphate (cAMP), was found to significantly reduce human TNFAIP1 mRNA levels and TNFAIP1 promoter activity in the SKNSH human neuroblastoma cell line as indicated by polymerase chain reaction analysis and a luciferase reporter assay. The association between transcription factor cAMP response element­binding protein (CREB) and TNFAIP1 was further investigated using loss- and gain of function-studies with western blot analysis and luciferase reporter assays. The CREB-specific inhibitor KG­501 significantly increased TNFAIP1 protein levels, while overexpression of wild­type CREB, but not CREB mutated at ser133a or its DNA-binding site, significantly decreased human TNFAIP1 protein levels and TNFAIP1 promoter activity in SKNSH cells. Furthermore, two CRE sites located at ­285 and ­425 bp of the human TNFAIP1 promoter were identified to be responsible for CREB­induced inhibition of human TNFAIP1 promoter activity. Chromatin immunoprecipitation assays confirmed that CREB bound to the TNFAIP1 promoter region harboring these two CRE sites. A further luciferase reporter assay demonstrated that CREB phosphorylation on ser133 was responsible for forskolin­induced inhibition of TNFAIP1 expression. In conclusion, the present study suggested that CREB is a negative regulator of the TNFAIP1 gene.

Enhancement of nitric oxide production by methylecgonidine in cultured neonatal rat cardiomyocytes.

1. In the present experiments, we investigated the effects of methylecgonidine (MEG) on nitric oxide (NO) production in cultured neonatal rat cardiomyocytes. Incubation of cultured cardiomyocytes with carbachol or MEG for 48 h significantly enhanced NO production. No release was increased from 1.48+/-0.13 microM (mg protein)(-1) for control to 5.73+/-0.19 microM (mg protein)(-1) for 1 microM carbachol treated cells (P<0.001). In addition, incubation with 1 microM MEG enhanced NO production to 5.55+/-0.28 microM (mg protein)(-1). The effects of MEG on NO production were concentration-dependent. The muscarinic antagonist atropine prevented the enhancement of NO production induced by carbachol or MEG. Compared to MEG-induced NO production, cocaine was much less potent. 2. The enhancement of NO production by carbachol or MEG was even greater in cultured cardiomyocytes transfected with the M(2) cDNA. After 48-h incubation with 1 microM carbachol or 1 microM MEG, NO production was increased by 6.5 and 6.7 fold, respectively, in cardiomyocytes overexpressing M(2) receptors. Coincubation with atropine or N(G)-nitro-L-arginine methyl ester abolished the enhancement of NO production. In contrast, NO production enhanced by carbachol or MEG in M(1)- or M(3)-transfected cardiomyocytes was similar to the level in non-transfected cells. 3. Western blot analysis showed that the protein levels of M(1), M(2), and M(3) were significantly increased in cardiomyocytes transfected with the receptor cDNAs, but MEG had no effect on the expressions. It is interesting that both carbachol and MEG caused a significant increase in constitutive endothelial NO synthase (eNOS) only in M(2)-transfected cardiomyocytes, not in non-transfected, M(1)- or M(3)-transfected cells. Again, atropine blocked the MEG-produced induction of eNOS. 4. Our data demonstrate that MEG significantly enhanced NO production in cultured cardiomyocytes and that the enhancement of NO production may result from MEG stimulation of muscarinic M(2) receptors.

Long-term improvement of cardiac function in rats after infarction by transplantation of embryonic stem cells.

OBJECTIVE: This study was designed to investigate the feasibility of and potential functional improvement with embryonic stem cell transplantation in rats 32 weeks after myocardial infarction. METHODS: Before cell transplantation, cultured embryonic stem cells were transfected with the complementary DNA of green fluorescent protein to identify engrafted cells in myocardium. Myocardial infarction was induced by ligation of the left coronary artery. Either 3 x 10(5) mouse embryonic stem cells or an equivalent volume of cell-free medium was injected into injured myocardium within 20 minutes after induction of myocardial infarction. RESULTS: Embryonic stem cell transplantation significantly increased the survival rate in rats undergoing myocardial infarction during the experimental period of 32 weeks. Hemodynamic and echocardiographic data showed that embryonic stem cell transplantation significantly improved ventricular function relative to the myocardial infarction plus medium control group. Tissue positive for green fluorescent protein was found in the injured myocardium with cell transplantation. The proportion of myocardium positively immunostained by antibodies against alpha-myosin heavy chain and cardiac troponin I was greater in the infarcted area with embryonic stem cell transplantation than in the injured myocardium with medium injection. Single green fluorescent protein-positive cells with a rod shape and clear striations were observed in cardiomyocytes isolated from infarcted hearts with embryonic stem cell transplantation. In addition, the number of blood vessels in injured myocardium was greater in the cell-transplanted myocardial infarction group than in the medium-injected myocardial infarction group. CONCLUSIONS: Engrafted embryonic stem cells differentiated into cardiomyocytes in injured myocardium, caused an angiogenetic effect, and subsequently improved cardiac function during the 32-week observation period.

VEGF enhances functional improvement of postinfarcted hearts by transplantation of ESC-differentiated cells.

Despite considerable advances in medicine, the incidence of heart failure remains high in patients after myocardial infarction (MI). This study investigated the effects of engrafted early-differentiated cells (EDCs) from mouse embryonic stem cells, with or without transfection of vascular endothelial growth factor (VEGF) cDNA (phVEGF(165)), on cardiac function in postinfarcted mice. EDCs were transfected with green fluorescent protein (GFP) cDNA and transplanted into infarcted myocardium. Compared with the MI mice receiving cell-free medium, cardiac function was significantly improved in the MI mice 6 wk after transplantation of EDCs. Moreover, improvement of heart function was significantly greater in the mice implanted with EDCs overexpressing VEGF (EDCs-VEGF) than with EDCs alone. Frozen sections of infarcted myocardium with EDCs or EDCs-VEGF transplantation showed GFP-positive tissue. The area with positive immunostaining for cardiac troponin I and alpha-myosin heavy chain was larger in injured myocardium with EDCs or EDCs-VEGF transplantation than with medium injection. Transplantation of EDCs or EDCs-VEGF significantly increased the number of blood vessels in the MI area. However, the density of capillaries was significantly higher in the EDCs-VEGF animals than in the EDC mice. Double staining for GFP and connexin-43 was positive in injured myocardium with EDC transplantation. Our data demonstrate that engrafted EDCs or EDCs-VEGF regenerated cardiac tissue and significantly improved cardiac function in postinfarcted hearts. The novel EDCs-VEGF synergistic approach may have an important impact on future cell therapy for patients experiencing MI or heart failure.

Transplantation of embryonic stem cells improves cardiac function in postinfarcted rats.

Massive loss of cardiac myocytes after myocardial infarction (MI) is a common cause of heart failure. The present study was designed to investigate the improvement of cardiac function in MI rats after embryonic stem (ES) cell transplantation. MI in rats was induced by ligation of the left anterior descending coronary artery. Cultured ES cells used for cell transplantation were transfected with the marker green fluorescent protein (GFP). Animals in the treated group received intramyocardial injection of ES cells in injured myocardium. Compared with the MI control group injected with an equivalent volume of the cell-free medium, cardiac function in ES cell-implanted MI animals was significantly improved 6 wk after cell transplantation. The characteristic phenotype of engrafted ES cells was identified in implanted myocardium by strong positive staining to sarcomeric alpha-actin, cardiac alpha-myosin heavy chain, and troponin I. GFP-positive cells in myocardium sectioned from MI hearts confirmed the survival and differentiation of engrafted cells. In addition, single cells isolated from cell-transplanted MI hearts showed rod-shaped GFP-positive myocytes with typical striations. The present data demonstrate that ES cell transplantation is a feasible and novel approach to improve ventricular function in infarcted failing hearts.

Significant improvement of heart function by cotransplantation of human mesenchymal stem cells and fetal cardiomyocytes in postinfarcted pigs.

BACKGROUND: Viable cardiomyocytes after myocardial infarction (MI) are unable to repair the necrotic myocardium due to their limited capability of regeneration. The present study investigated whether intramyocardial transplantation of human mesenchymal stem cells (hMSCs) or cotransplantation of hMSCs plus human fetal cardiomyocytes (hFCs; 1:1) reconstituted impaired myocardium and improved cardiac function in MI pigs. METHODS AND RESULTS: Cultured hMSCs were transfected with green fluorescent protein (GFP). Six weeks after MI induction and cell transplantation, cardiac function was significantly improved in MI pigs transplanted with hMSCs alone. However, the improvement was even markedly greater in MI pigs cotransplanted with hMSCs plus hFCs. Histological examination demonstrated that transplantation of hMSCs alone or hMSCs plus hFCs formed GFP-positive engrafts in infarcted myocardium. In addition, immunostaining for cardiac alpha-myosin heavy chain and troponin I showed positive stains in infarcted regions transplanted with hMSCs alone or hMSCs plus hFCs. CONCLUSIONS: Our data demonstrate that transplantation of hMSCs alone improved cardiac function in MI pigs with a markedly greater improvement from cotransplantation of hMSCs plus hFCs. This improvement might result from myocardial regeneration and angiogenesis in injured hearts by engrafted cells.

Electrophysiologic properties of lidocaine, cocaine, and n-3 fatty-acids block of cardiac Na+ channels.

Lidocaine and cocaine, two local anesthetics, and n-3 polyunsaturated fatty acids in fish oils, inhibit the voltage-gated Na(+) channels of cardiomyocytes. This inhibition by lidocaine and n-3 fish oil is associated with antiarrhythmic effects, whereas with cocaine lethal arrhythmias may occur. These electrophysiologic studies show that at the concentrations tested, the n-3 fish oil fatty acids and lidocaine share three actions on I(Na): a potent inhibition of I(Na); a strong voltage-dependence of this inhibition; and a large shift of the steady-state inactivation to hyperpolarized potentials. By contrast cocaine shares only the potent inhibition of I(Na). The voltage-dependence of the inhibition is much decreased with cocaine, which produces only a very small leftward shift of the voltage-dependence of inactivation. The large leftward shift of the steady-state inactivation seems very important in the prevention of fatal arrhythmias by the n-3 fatty acids. Thus, we suggest that it is lack of this effect by cocaine, which is one factor, that eliminates its ability to prevent fatal cardiac arrhythmias. Further we report that in cultured neonatal rat cardiomyocytes n-3 fish oil fatty acids terminate the tachycardia induced by the alpha(1) adrenergic agonist, phenylephrine, whereas cocaine accelerates the tachycardia and causes bouts of tachyarrhythmias.

Induction of cardiac cytochrome p450 in cocaine-treated mice.

Cytochrome P450 (P450) is a ubiquitous family of enzymes responsible for the metabolism of a wide variety of drugs and their metabolites, including cocaine. To investigate the effects of cocaine on myocardial injuries and cardiac P450 expression, BALB/c mice were injected daily intraperitoneally with cocaine (30 mg/kg) or cocaine plus pretreatment of P450 inhibitors for 14 days. Tumor necrosis factor-alpha (TNF-alpha) content and creatine phosphokinase (CPK) activity in mice hearts and serums were significantly increased after long-term treatment with cocaine. Pretreatment with the P450 inhibitor, cimetidine (Cime, 50 mg/kg) or metyrapone (Mety, 40 mg/kg) abolished or significantly attenuated the effects of cocaine on TNF-alpha and CPK activity. Western blot analysis shows that mouse cardiac tissues express the P450 isoforms CYP1A1, CYP1A2, and CYP2J2. The protein levels normalized with cyclophilin A were 1.20 plus minus 0.07, 0.67 plus minus 0.03, and 1.48 plus minus 0.01 for CYP1A1, CYP1A2, and CYP 2J2, respectively. After cocaine administration, CYP2J2 increased by 43.6% and CYP1A1 increased by 108.5%, but CYP1A2 was not significantly altered. However, the cytochrome P450 inhibitors Cime and Mety suppressed the cocaine-induced increase in CYP1A1 and CYP2J2 expression. Moreover, application of Cime or Mety alone did not alter the level of cardiac TNF-alpha or the expression of P450. Our results demonstrate that long-term exposure to cocaine causes an increase in cardiac CYP1A1 and CYP2J2 concentration. We speculate that induction of P450 isoforms may cause cardiac injury due to cocaine metabolites locally catalyzed by P450 or the increase in P450 expression itself.