The prognostic value of soluble Klotho in patients with haemodialysis: a systematic review and meta-analysis.

AIM: The correlation between soluble Klotho (sKlotho) levels and clinical outcomes remains inconclusive for patients undergoing maintenance haemodialysis (MHD). We aimed to evaluate the potential predictive significance of sKlotho in this population by conducting a meta-analysis. METHODS: PubMed, Embase, Web of Science and Cochrane Library were comprehensively searched for studies concerning the association between sKlotho level and clinical outcomes including cardiovascular (CV) events and all-cause mortality. The pooled hazard ratios (HR) and 95% confidence intervals (CI) were generated using either random or fixed effects models. Sensitivity and subgroup analyses were used to explore heterogeneity sources. RESULTS: Eight prospective studies with 992 MHD participants were included and reduced sKlotho levels predicted more adverse outcomes in this meta-analysis. The pooled HRs and 95% CIs related to CV events, mortality, or composite outcomes were 1.73 (95% CI 1.08-2.76, p = 0.02), 2.34 (95% CI 1.34-2.07, p = 0.003) or 1.75 (95% CI 1.19-2.57, p = 0.005). Moderate heterogeneity was observed in the composite adverse outcomes (I 2 = 57%, p = 0.05). Age and sKlotho level were the main sources of heterogeneities in the subgroup analysis. CONCLUSION: Lower sKlotho levels were associated with more CV events and all-cause mortality, suggesting that sKlotho may have predictive value in CKD patients receiving haemodialysis.

Association of the presence of microangiopathy with adverse pregnancy outcome in type 1 diabetes: A meta-analysis.

OBJECTIVE: Microangiopathy is common after a long duration in type 1 diabetes mellitus (T1DM). Pregnancies with end-age vascular complications are a big challenge to multidisciplinary physicians. The objective of this study was to assess the risk of microangiopathy for adverse pregnancy outcome in T1DM. MATERIALS AND METHODS: PubMed, EMBASE, and Cochrane Library databases were searched for relevant articles appearing in the literature up to October 1, 2017. Analysis of cohort studies were performed with Review Manager 5.3 and Newcastle Ottawa Scale (NOS) was chosen to evaluate the risk of bias. RESULTS: A total of 10 studies involving 3239 pregnancies were retrieved and analyzed. Microangiopathy for diabetic nephropathy (DN), microalbuminuria and diabetic retinopathy (DR) significantly increased the risk of preeclampsia (PE) (OR of 7.19, [95%CI: 5.15, 10.03], 4.19, [95%CI: 2.78, 6.31] and 3.02, [95%CI: 2.24, 4.07], respectively). Significant association of the presence of DN with preterm delivery was demonstrated (OR = 4.14, 95%CI [2.84, 6.02]), with small for gestation age was demonstrated (OR = 6.23, 95%CI [2.75, 14.14]) and with large for gestation age was demonstrated (OR = 0.41, 95%CI [0.27, 0.62]). A mild association of the presence of DR with preterm delivery was demonstrated (OR = 1.57, 95%CI [1.08, 2.29]). CONCLUSION: The presence of microangiopathy before or in early pregnancy increased the risk of adverse pregnancy outcome in T1DM. We highlighted it was important that White's classification and a full assessment of vasculopathy should be carry out before pregnancy to ensure a well-planned pregnancy. Further work should be designed to establish risks model involving microangiopathy and find out whether early intervention with strict blood sugar control or medication such as low-dose aspirin will reduce the incidence of PE in T1DM.

Oleanolic acid attenuates TGF-ß1-induced epithelial-mesenchymal transition in NRK-52E cells.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) plays an important role in the progression of renal interstitial fibrosis, which finally leads to renal failure. Oleanolic acid (OA), an activator of NF-E2-related factor 2 (Nrf2), is reported to attenuate renal fibrosis in mice with unilateral ureteral obstruction. However, the role of OA in the regulation of EMT and the underlying mechanisms remain to be investigated. This study aimed to evaluate the effects of OA on EMT of renal proximal tubular epithelial cell line (NRK-52E) induced by TGF-ß1, and to elucidate its underlying mechanism. METHODS: Cells were incubated with TGF-ß1 in the presence or absence of OA. The epithelial marker E-cadherin, the mesenchymal markers, α-smooth muscle actin (α-SMA), fibronectin, Nrf2, klotho, the signal transducer (p-Smad2/3), EMT initiator (Snail), and ILK were assayed by western blotting. RESULTS: Our results showed that the NRK-52E cells incubated with TGF-ß1 induced EMT with transition to the spindle-like morphology, down-regulated the expression of E-cadherin but up-regulated the expression of α-SMA and fibronectin. However, the treatment with OA reversed all EMT markers in a dose-dependent manner. OA also restored the expression of Nrf2 and klotho, decreased the phosphorylation of Smad2/3, ILK, and Snail in cells which was initiated by TGF-ß1. CONCLUSION: OA can attenuate TGF-ß1 mediate EMT in renal tubular epithelial cells and may be a promising therapeutic agent in the treatment of renal fibrosis.

Long non-coding RNA MALAT1 interacts with transcription factor Foxo1 to regulate SIRT1 transcription in high glucose-induced HK-2 cells injury.

BACKGROUND: Tubular injury is considered as a crucial pathological feature of diabetic nephropathy. LncRNA MALAT1 is involved in diabetic complications. Hence the role of MALAT1 in high glucose-induced renal tubular epithelial cells (HK-2) injury deserves investigation. METHODS: The diabetic mice model was established with streptozotocin (STZ) injection. The expression of NEAT1, SIRT1, and Foxo1 mRNA and protein was determined with qRT-PCR and western blot, respectively. The serum creatinine and urinary albumin were examined by enzyme linked immunosorbent assay (ELISA). Interaction between MALAT1 and Foxo1 was detected with RIP and RNA pull-down assay, respectively. Dual luciferase reporter assay was used to evaluate the binding between Foxo1 and SIRT1. RESULTS: LncRNA MALAT1 was up-regulated in kidney tissues of diabetic mice and in HK-2 cells treated with high glucose, while the expression of SIRT1 was decreased. Interaction between MALAT1 and Foxo1 was observed in HK-2 cells and the interaction was promoted by high glucose treatment. Foxo1 activated SIRT1 transcription by binding to its promoter, and MALAT1 repressed SIRT1 expression through targeting Foxo1. CONCLUSION: LncRNA MALAT1 interacts with transcription factor Foxo1 to represses SIRT1 transcription in high glucose incubated HK-2 cells, which promotes high glucose-induced HK-2 cells injury.

Impact of Volume Management on Volume Overload and Rehospitalization in CAPD Patients.

Heart failure due to volume overload is a major reason for rehospitalization in continuous ambulatory peritoneal dialysis patients. Strict volume control provides better cardiac functions and blood pressure in this population. Volume management, which is a volume control strategy, may decrease volume overload and related complications. Using a quasi-experimental design, 66 continuous ambulatory peritoneal dialysis patients were randomly assigned to the intervention group ( n = 34) and control group ( n = 32). The patients were followed up for 6 months with scheduled clinic and/or telephone visits; the intervention group adopted volume management strategy, while the control group adopted conventional care. Volume overload and cardiac function were compared between the two groups at the baseline and at 6 months. At Month 6, the intervention group resulted in significant improvement in volume overloaded status, cardiac function, and volume-overload-related rehospitalization. Volume management strategy allows for better control of volume overload and is associated with fewer volume-related readmissions.

Alteration of circulatory platelet microparticles and endothelial microparticles in patients with chronic kidney disease.

OBJECTIVE: To compare plasma platelet microparticles (PMPs), P-selectin, endothelial microparticles (EMPs), and von Willebrand factor (vWF) between a normal control group and patients with chronic kidney disease (CKD) and to explore the significance of PMPs and EMPs in CKD. METHODS: Levels of plasma PMPs, P-selectin, EMPs and vWF in 122 CKD patients and 20 normal controls were detected by flow cytometry and enzyme-linked immunosorbent assay (ELISA). Relationships between PMPs, EMPs and blood pressure, creatinine clearance rate, 24-hour urine protein, hemoglobin, and cholesterol were analyzed. RESULTS: (1) Plasma PMPs, P-selectin, EMPs and vWF levels in CKD patients were significantly higher than those of the control group. Plasma PMPs and P-selectin levels for nephrotic syndrome (NS) were significantly higher than for other CKD groups. No significant difference was found between other CKD groups. Plasma EMPs and vWF in NS, lupus nephritis (LN) and hypertensive nephropathy groups were significantly higher than that of diabetic nephropathy (DN) and chronic glomerulonephritis (CGN) groups. (2) Plasma PMPs, P-selectin, EMPs and vWF in stage I-II CKD patients were significantly higher than those of stage III-V CKD patients, no significant difference was found within stage I-II CKD patients or stage III-V CKD patients. (3) PMPs and EMPs were positively correlated with blood pressure and 24-hour urinary protein, but no significant correlation was found with the creatinine clearance rate, hemoglobin or cholesterol. P-selectin and vWF were positively correlated with PMPs and EMPs respectively. CONCLUSION: CKD patients have significant platelet activation and endothelial dysfunction, which was involved in CKD's occurrence and development; high blood pressure and proteinuria are important reasons for platelet activation and endothelial dysfunction in patients with CKD; PMPs and EMPs can be used as new markers for dysfunctional platelet activation and endothelium.

High glucose induces renal tubular epithelial injury via Sirt1/NF-kappaB/microR-29/Keap1 signal pathway.

OBJECTIVE: Diabetic nephropathy (DN) is a serious complication that commonly confronted by diabetic patients. A common theory for the pathogenesis of this renal dysfunction in diabetes is cell injury, inflammation as well as oxidative stress. In this content, the detailed molecular mechanism underlying high glucose induced renal tubular epithelial injury was elaborated. METHODS: An in vivo rat model of diabetes by injecting streptozotocin (STZ) and an in vitro high glucose incubated renal tubular epithelial cell (HK-2) model were used. Expression levels of Keap1, nuclear Nrf2 and p65 were determined by western blotting. Level of microR-29 (miR-29) was assessed using quantitative RT-PCR. Combination of p65 and miR-29 promotor was assessed using chromatin immunoprecipitation. Keap1 3'-UTR activity was detected using luciferase reporter gene assay. Cell viability was determined using MTT assay. RESULTS: In diabetic rat, miR-29 was downregulated and its expression is negatively correlated with both of serum creatinine and creatinine clearance. In high glucose incubated HK-2 cell, deacetylases activity of Sirt1 was attenuated that leads to decreased activity of nuclear factor kappa B (NF-κB). NF-κB was demonstrated to regulate miR-29 expression by directly binding to its promotor. The data of luciferase assay showed that miR-29 directly targets to Keap1 mRNA. While high glucose induced down regulation of miR-29 contributed to enhancement of Keap1 expression that finally reduced Nrf2 content by ubiquitinating Nrf2. Additionally, overexpression of miR-29 effectively relieved high glucose-reduced cell viability. CONCLUSION: High glucose induces renal tubular epithelial injury via Sirt1/NF-κB/microR-29/Keap1 signal pathway.

Long non-coding MIAT mediates high glucose-induced renal tubular epithelial injury.

BACKGROUND AND OBJECTIVE: Long non-coding RNAs (lncRNAs) constitute a novel class of non-coding RNAs that take part in occurrence and development of diabetes complication via regulating gene expression. However, litter is known about lncRNAs in the setting of diabetes induced nephropathy. The aim of this study was to examine whether lncRNA-myocardial infarction-associated transcript (MIAT) is involved in diabetes induced renal tubules injury. METHODS: Adult Wister rats were randomly assigned to receive intraperitoneal STZ (65 mg/kg) to induce diabetes. Rats treated with equal volume of citrate buffer were as control. Renal function was evaluated by analysis of serum creatinine and blood urea nitrogen (BUN) every four weeks after STZ administration. Also tubules of all rats were collected for determination of MIAT and Nrf2 level at the corresponding phase. The in vitro high glucose-triggered human renal tubular epithelial cell line (HK-2) was used to explore the mechanism underling MIAT regulated high glucose-induced tubular damage. RESULTS: In diabetic rats, MIAT showed the lower level and its expression is negatively correlated with serum creatinine and BUN. Consistent with diabetic rat, exposed to high glucose, HK-2 cells expressed lower level of MIAT and Nrf2, and also showed reduction in cell viability. By pcDNA-MIAT plasmid transfection, we observed that MIAT overexpression reversed inhibitory action of Nrf2 expression by high glucose. Moreover, the data of RNA pull-down and RIP showed that MIAT controlled Nrf2 cellular through enhancing Nrf2 stability, which was confirmed by CHX and MG132 administration. Inhibitory effect of cell viability by silencing MIAT was also reversed by Nrf2 overexpression. CONCLUSION: In summary, our data suggested that MIAT/Nrf2 served as an important signaling pathway for high glucose induced renal tubular epithelial injury.

Down-regulation of miR-186 contributes to podocytes apoptosis in membranous nephropathy.

BACKGROUND AND AIM: Podocytes apoptosis is the key process in the development of membranous nephropathy and miR-186 is reported to be related with cell apoptosis. Here we investigated the expression of miR-186 in membranous nephropathy (MGN) patients and the mechanism underlying the podocytes apoptosis. METHODS: Thirty patients with MGN and 30 healthy people were included in this study. The expression of miR-186 was detected in renal tissue and podocyte cells exposed to AngII by real-time PCR. Caspase-3 activity was used to evaluate podocytes apoptosis. TLR4 and P2×7 protein expression was quantified by western blotting. miR-186 inhibitor and miR-186 mimic were transfected into cells to investigate the mechanism underlying miR-186 in podocytes apoptosis. RESULTS: In MGN patients, the level of miR-186 was significantly down-regulated as well as the protein expression of TLR4 and P2×7 was up-regulated in renal tissue. In vitro experiments, TLR4 siRNA increased the expression of miR-186 and miR-186 inhibitor elevated the mRNA and protein expression of P2×7 in podocytes exposed to AngII. In addition, the level of cleaved-caspase-3 was up-regulated by miR-186 inhibitor. The TUNEL-positive cells and caspase-3 activity of podocytes induced by AngII were down-regulated by miR-186 mimic. CONCLUSIONS: We revealed that TLR4 is involved in the regulation of miR-186 expression, and the anti-apoptotic effect of miR-186 on podocytes is correlated with P2×7 regulation.

Development and Testing of Self-Management Scale for PD Patients.

OBJECTIVES: To develop and evaluate the self-management scale for peritoneal dialysis (PD) patients. METHODS: The item pool was formulated based on literature reviews and in-depth interviews. An initial scale containing five factors and 44 items was constructed through two rounds of Delphi expert consultation and a preliminary test. A total of 313 PD patients from the Jiangsu-Zhejiang-Shanghai area were surveyed to test the reliability and validity of the scale. RESULTS: Five factors, namely solution bag replacement, troubleshooting during operation, diet management, complication monitoring, emotion management and return to social life, were extracted by exploratory factor analysis: the 28 items could explain 64.567% of the total variance; the content validity index was 0.963; the Cronbach's α coefficient and split-half coefficient were 0.926 and 0.960 respectively; and test-retest reliability was 0.937. CONCLUSION: The scale has been proved to be a reliable and valid tool which allows PD nurses to evaluate the self-management ability of PD patients. The evaluation outcomes can serve as a basis for individualized nursing plans and interventions so as to provide highly effective nursing care.

Synthesis and enhanced DNA cleavage activities of bis-tacnorthoamide derivatives.

A new metal-free DNA cleaving reagent, bis-tacnorthoamide derivative 1 with two tacnorthoamide (tacnoa) units linked by a spacer containing anthraquinone, has been synthesized from triazatricyclo[5.2.1.0(4,10)]decane and characterized by NMR and mass spectrometry. For comparison, the corresponding compounds mono-tacnorthoamide derivative 2 with one tacnorthoamide unit and 6 with two tacnorthoamide units linked by an alkyl (1,6-hexamethylene) spacer without anthraquinone have also been synthesized. The DNA-binding property investigated via fluorescence and CD spectroscopy suggests that compounds 1 and 2 have an intercalating DNA binding mode, and the apparent binding constants of 1, 2 and 6 are 1.3 × 10(7) M(-1), 0.8 × 10(7) M(-1) and 8 × 10(5) M(-1), respectively. Agarose gel electrophoresis was used to assess plasmid pUC19 DNA cleavage activity promoted by 1, 2, 6 and parent tacnoa under physiological conditions, which gives rate constants k(obs) of 0.2126 ± 0.0055 h(-1), 0.0620 ± 0.0024 h(-1), 0.040 ± 0.0007 h(-1) and 0.0043 ± 0.0002 h(-1), respectively. The 50-fold and 15-fold rate acceleration over parent tacnoa is because of the anthraquinone moiety of compound 1 or 2 intercalating into DNA base pairs via a stacking interaction. Moreover, DNA cleavage reactions promoted by compound 1 give 5.3-fold rate acceleration over compound 6, which further demonstrates that the introduction of anthraquinone results in a large enhancement of DNA cleavage activity. In particular, DNA cleavage activity promoted by 1 bearing two tacnoa units is 3.3 times more effective than 2 bearing one tacnoa unit and the DNA cleavage by compound 1 was achieved effectively at a relatively low concentration (0.03 mM). This dramatic rate acceleration suggests the cooperative catalysis of the two positively charged tacnoa units in compound 1. The radical scavenger inhibition study and ESI-MS analysis of bis(2,4-dinitrophenyl) phosphate (BDNPP) and adenylyl(3'-5')phosphoadenine (APA) cleavage in the presence of compound 1 suggest the cleavage mechanism would be via a hydrolysis pathway by cleaving the phosphodiester bond of DNA.

Photophysical and electrochemical properties of donor-acceptor conjugated oligomers based on 3,4-ethylenedioxythiophene and deficient rings.

The photophysical and electrochemical properties of four novel donor-accepter (D-A) conjugated oligomers a-d based on 3,4-ethylenedioxythiophene (EDOT) and electrondeficient heterocycle rings were investigated. The UV-vis absorption spectroscopy, fluorescence emission spectroscopy and cyclic voltammertry studies suggest that the oligomers are expected to provide enhanced charge-transporting properties for the development of efficient electroluminescent materials. Furthermore, the third-order nonlinear optical (NLO) measurements made by Z-scan technique indicate that they have good third-order NLO response and are desired materias for fabricating nonlinear photonic devices. In the solid state of these oligomers, a strong tendency of self-assembled structure was also revealed by X-ray diffraction (XRD) patterns in powder.

A novel mediator-free biosensor based on co-intercalation of DNA and hemoglobin in the interlayer galleries of alpha-zirconium phosphate.

A novel mediator-free biosensor was constructed by the co-intercalation of negatively charged DNA and positively charged hemoglobin (Hb) in the interlayer galleries of layered alpha-zirconium phosphate (alpha-ZrP) with the delamination-assembly procedure at pH 5.5. X-ray diffraction and field-emission scanning electron microscopy results revealed the featured layered structure for the re-assembled DNA/Hb/alpha-ZrP composite. Infrared spectroscopy and circular dichroism results confirmed the coexistence of Hb and DNA in the composite and the considerably retained protein conformation of intercalated Hb. The direct electron transfer of Hb was facilitated by the co-intercalation of DNA and Hb. Because of the synergistic effect of alpha-ZrP host and co-intercalated DNA guest, the DNA/Hb/alpha-ZrP modified electrode exhibited good electrocatalytic response to H(2)O(2) with higher sensitivity of 0.79 A M(-1) cm(-2) and lower detection of 4.28x10(-7) M in the linear range of 7.28x10(-7) to 9.71x10(-5) M. Furthermore, the electrocatalytic activity of Hb in the DNA/Hb/alpha-ZrP composite retained at high temperature (85 degrees C) or in the presence of organic solvent (CH(3)CN), which could be the protection of alpha-ZrP nanosheets.

pH-induced fabrication of DNA/chitosan/alpha-ZrP nanocomposite and DNA release.

With positively charged chitosan as an intermediary, herring sperm DNA was intercalated into the interlayer galleries of negatively charged alpha-ZrP to form DNA/chitosan/alpha-ZrP ternary hybrids at pH 5.5. Fourier-transform IR, x-ray diffraction and scanning electron microscopy confirmed not only the coexistence of DNA, chitosan and alpha-ZrP in the composite but also the layered composite structure with an interlayer distance of 4.25 nm. Circular dichroism (CD) and UV spectroscopic studies disclosed that the restraint of DNA by the layered alpha-ZrP favors stabilization of the double-helical conformation of DNA and enhances the denaturation temperature. The intercalated DNA can be effectively released from the ternary nanocomposites at pHs higher than 6.5, and the released DNA displayed a similar CD spectrum to that of free DNA. The current research displays the promising potential to obtain a non-viral gene vector by intercalating DNA into negatively charged inorganic layered materials in the presence of a positively charged intermediary.

2-[3-((Z)-2-{4-[Bis(2-chloro-eth-yl)amino]-phen-yl}ethen-yl)-5,5-dimethyl-cyclo-hex-2-en-1-yl-idene]propane-dinitrile.

The highly conjugated title compound, C(23)H(25)Cl(2)N(3), is nearly planar (the mean deviation from the plane being 0.049 Å), except for the -C(CH(3))(2) group on the cyclo-hexene ring and the two CH(2)Cl groups. The cyclo-hexene ring has an envelope configuration. In the crystal, the packing is stabilized by C-H⋯Cl inter-actions and C-H⋯π inter-actions involving the benzene ring.

Significant effect of bromo substituents on nonlinear optical properties of polymer and chromophores.

Four chromophores containing bromo substituents, a ployimide with bromo-containing chromophores, four reference functional polyimides, and fourteen reference chromophores were synthesized for studying effect of bromo substituents on nonlinear optical (NLO) properties of materials and chromophores. The results of hyper-Rayleigh scattering and UV-vis spectra show that static first molecular hyperpolarizability (beta(0)) values of bromo-containing chromophores are 1.24-5.75 times as beta(0) of the corresponding chloro-containing chromophores (Hammett constants sigma of chloro and bromo groups are same) without causing a visible shift of the absorption band to longer wavelength. UV-vis spectra and the results of Maker Fringe method show that the polyimide with chromophores containing bromo substituents exhibits a good optical transparency and a much higher macroscopic nonlinear optical coefficient (d(33) = 20.1 pm/V) than the reference polyimides containing nitro (d(33) = 9.6 pm/V) and cyano (d(33) = 8.9 pm/V) groups in spite of nitro and cyano groups being strong electron acceptors. d(33) of polyimide with chloro-containing chromophores is very small. Therefore, this paper suggests an effective strategy for improving the NLO properties of polymeric materials and chromophores without reducing optical transparency in designing NLO polymers and chromophores. On the basis of quantum chemistry calculations, the reasons of effect of bromo substituents on NLO properties of chromophores and materials were discussed.

Theoretical study of nonlinear optical properties of "parallel connection" chromophores containing parallel nonconjugated D-pi-A units.

Chromophores containing two parallel nonconjugated D-pi-A units are effective chromophores with high hyperpolarizability and good optical transparency. It provides a method for the design and synthesis of effective chromophores. The semiempirical method ZINDO was employed to study the relationship between enhancement of the static first hyperpolarizabilities (beta0) per D-pi-A unit and the number of parallel nonconjugated D-pi-A units in a chromophore. The results show that the chromophores containing two parallel nonconjugated D-pi-A units would exhibit higher beta0 values than two times the beta0 value of the corresponding reference chromophore containing a D-pi-A unit. The chromophore containing three parallel nonconjugated D-pi-A units exhibits the highest enhancement of beta0 per D-pi-A unit, which is 10.1 times the beta0 value of the corresponding reference chromophore. However, the beta0 value of the chromophore containing four parallel nonconjugated D-pi-A units is very small, and the enhancement of beta0 value per D-pi-A unit decreases sharply, from 10.1 to 0.3, with increasing the number of parallel D-pi-A units in a chromophore from 3 to 4. It could give a useful suggestion for designing chromophores containing parallel nonconjugated D-pi-A units.

Langmuir monolayer and Langmuir-Blodgett films formed by a melamine-headed azobenzene-derived amphiphile: interfacial assembly affected by host-guest interaction.

A novel azobenzene-derived amphiphile with a melamine head, 2Azo-2C12H2-melamine, has been synthesized. pi-A isotherm measurements displayed that this amphiphile is able to form a stable Langmuir monolayer on both pure water and barbituric acid (BA)- or thymine (T)-containing subphases. The collapse surface pressure and limiting molecular area of its Langmuir monolayer on pure water are 40 mN/m and 0.56 nm2, respectively. However, when barbituric acid or thymine was introduced into the subphase, the corresponding pi-A isotherms of the monolayers exhibited a lower collapse surface pressure (22 mN/m for BA, 21 mN/m for T) and smaller limiting molecular area (0.54 nm2 for BA and 0.52 nm2 for T). UV-vis and FT-IR studies of the LB films formed by 2Azo-2C12H25-melamine have also been carried out. The results indicated that the LB films of 2Azo-2C12H25-melamine deposited from pure water undergo distinct collapse of the H-aggregate upon UV irradiation, while the LB films deposited from a BA- or T-containing subphase retain the H-aggregate. The host-guest-interaction-induced blockage of azobenzene photoisomerization should be responsible for the stabilized H-aggregate. A 1:1 host/guest binding mode to form a linear supramolecular polymeric chain has been proposed in the Langmuir monolayers formed on a BA- or T-containing subphase. The current results suggest that the host-guest interaction should be an effective means to manipulate the interfacial assembly of azobenzene-derived amphiphiles.

Synthesis and DNA cleavage activity of 2-hydrazinyl-1,4,5,6-tetrahydropyrimidine containing hydroxy group.

2-Hydrazinyl-1,4,5,6-tetrahydropyrimidin-5-ol dihydrochloride 2, as well as 2-hydrazinyl-4,5-dihydro-1H-imidazole dihydrochloride 1, was synthesized as metal-free DNA cleaving agent. Agarose gel electrophoresis was used to assess the plasmid pUC 19 DNA cleavage activities in the presence of 1 and 2. DNA cleavage efficiency of 2 exhibits remarkable increases compared with its corresponding non-hydroxy compound 1. Kinetic data of DNA cleavage promoted by 2 fit to the Michaelis-Menten-type equation with k(max) of 0.0378+/-0.0013 h(-1) giving 10(6)-fold rate acceleration over uncatalyzed DNA. The acceleration is driven by the spatial proximity of the nucleophilic hydroxy group and the electrophilic activation for the phosphodiester by the ammonium and/or guanidinium groups. In vitro cytotoxic activities toward Hela cells and human leukemia HL-60 cells were also examined, and 2 exhibits stronger cytotoxic activities than 1.

DNA binding and cleaving activity of the new cleft molecule N,N'-Bis(guanidinoethyl)-2,6-pyridinedicarboxamide in the absence or in the presence of copper(II).

Novel cleft molecule pyridine-2,6-dicarboxamide appending two guanidinoethyl group side arms (Gua) was synthesized. The interactions of the cleft molecule in the absence of copper(II) (Gua) or in the presence of copper(II) (Cu2+-Gua) with calf thymus DNA were studied by fluorescence and CD spectroscopy. The results indicate that the DNA binding affinity of Cu2+-Gua is stronger than that of Gua, and the binding constants of Cu2+-Gua and Gua are 1.61 x 10(6) M(-1) and 2.86 x 10(5) M(-1), respectively. Agarose gel electrophoresis was used to assess the plasmid pUC 19 DNA cleavage activities in the presence of Gua and Cu2+-Gua. Kinetic data of DNA cleavage promoted by Cu2+-Gua under physiological conditions fit a saturation kinetic profile with k(max) of 0.0173 +/- 0.0011 h(-1), which gave a aproximately 10(6)-fold rate acceleration over uncatalyzed supercoiled DNA, while the catalyst concentration is lower than 0.0625 mM. The hydrolysis pathway was proposed as the possible mechanism for DNA cleavage promoted by Cu2+-Gua. The acceleration is due to efficient cooperative catalysis of the copper cation center and the functional groups (bis(guanidinium) groups).