Visual detection of water content in liquor with near-infrared fluorescence sensor assisted by smartphone

Water content was an essential indicator in organic solvents, and it was necessary to develop a facile, cheap and readily available tool for the real-time, specifical and sensitive detection of water content. In this work, two novel D-π-A type near-infrared fluorescence sensors (DCM-1 and DCM-2) were designed and synthesized for the detection of trace water in organic solvents. DCM-1 and DCM-2 with solvent-dependent effects and large Stokes shift (>120 nm) showed good linear "intensity-to-content" relationships in four commonly-used organic solvents, and accomplished the ultra-fast and high-accuracy detection of the trace water in organic solvents. More importantly, a portable, fast, and accurate smartphone-assisted visual assay was designed for visual quantitative detection of the water content in organic solvents with a detection limit as low as 1.028 % v/v (e.g. in ethanol) and a wide detection range (0-60 % v/v). The smartphone-based visual assay was further applied to estimate the water content in disinfection alcohol and commercial liquor, which furnished a new strategy and broad prospects to achieve the accurate onsite detection of water content.

Zero-Dimensional Carbon Nanomaterials for Fluorescent Sensing and Imaging

Advances in nanotechnology and nanomaterials have attracted considerable interest and play key roles in scientific innovations in diverse fields. In particular, increased attention has been focused on carbon-based nanomaterials exhibiting diverse extended structures and unique properties. Among these materials, zero-dimensional structures, including fullerenes, carbon nano-onions, carbon nanodiamonds, and carbon dots, possess excellent bioaffinities and superior fluorescence properties that make these structures suitable for application to environmental and biological sensing, imaging, and therapeutics. This review provides a systematic overview of the classification and structural properties, design principles and preparation methods, and optical properties and sensing applications of zero-dimensional carbon nanomaterials. Recent interesting breakthroughs in the sensitive and selective sensing and imaging of heavy metal pollutants, hazardous substances, and bioactive molecules as well as applications in information encryption, super-resolution and photoacoustic imaging, and phototherapy and nanomedicine delivery are the main focus of this review. Finally, future challenges and prospects of these materials are highlighted and envisaged. This review presents a comprehensive basis and directions for designing, developing, and applying fascinating fluorescent sensors fabricated based on zero-dimensional carbon nanomaterials for specific requirements in numerous research fields.

High sensitivity for detecting trace Sn2+ in canned food using novel covalent organic frameworks

Tin (Sn) element plays a vital role in the human body, and its detection is a mandatory inspection item for canned food. The application of covalent organic frameworks (COFs) in fluorescence detection has received extensive attentions. In this work, we designed a kind of novel COFs (COF-ETTA-DMTA) with high specific surface area (353.13 m²/g) by solvothermal synthesis using 2,5-dimethoxy-1,4-dialdehyde and tetra (4-aminophenyl) ethylene as precursors. It shows fast response time (about 50 s), low detection limit (228 nM) and good linearity (R² = 0.9968) for the detection of Sn²⁺. Via coordination behavior, the recognition mechanism of COFs toward Sn²⁺ was simulated and verified by the small molecule with the same functional unit. More importantly, this COFs was successfully applied to identify Sn²⁺ in solid canned food (luncheon pork, canned fish, canned red kidney beans) with satisfactory results. This work provides a new approach for determining metal ions with COFs taking the advantage of their natural rich reaction set and specific surface area, improving the detection sensitivity and capacity.

Photocatalytic Cascade Reaction Driven by Directed Charge Transfer over VS -Zn0.5 Cd0.5 S/GO for Controllable Benzyl Oxidation

Photocatalysis is an important technique for synthetic transformations. However, little attention has been paid to light-driven synergistic redox reactions for directed synthesis. Herein, the authors report tunable oxidation of benzyl to phenylcarbinol with the modest yield (47%) in 5 h via singlet oxygen (¹ O₂ ) and proton-coupled electron transfer (PCET) over the photocatalyst Zn_0.5 Cd_0.5 S (ZCS)/graphene oxide (GO) under exceptionally mild conditions. Theoretical calculations indicate that the presence of S vacancies on the surface of ZCS/GO photocatalyst is crucial for the adsorption and activation of O₂ , successively generating the superoxide radical (^• O₂ ^- ) and ¹ O₂ , attributing to the regulation of local electron density on the surface of ZCS/GO and photogenerated holes (h⁺ ). Meanwhile, accelerated transfer of photogenerated electrons (e^- ) to GO caused by the π-π stacking effect is conducive to the subsequent aldehyde hydrogenation to benzyl alcohol rather than non-selective oxidation of aldehyde to carboxylic acid. Anisotropic charge transport driven by the built-in electric field can further promote the separation of e^- and h⁺ for multistep reactions. Promisingly, one-pot photocatalytic conversion of p-xylene to 4-methylbenzyl alcohol is beneficial for reducing the harmful effects of aromatics on human health. Furthermore, this study provides novel insights into the design of photocatalysts for cascade reactions.

Multisite-Sequential Cyclization To Construct 1,2,4-Triazole-Based N-Fused Heterocyclics

A feasible protocol that uses atomic groups (KSCN, KSeCN, and NH₂CN), o-bromobenzoyl hydrazides, and formyls as reaction factors to synthesize N-fused 1,2,4-triazole with benzothiazides, benzoselenazinones, and quinazolinones was proposed. The method overcomes the lengthy multistep synthesis, narrow substrate scope, and toxicity challenge induced by the use or production of hazardous substances. It also enables the development of fused-heterocyclic selenium and quinazolinone derivatives. Their fluorescent performance further demonstrates the practicability of this methodology.

A Highly Sensitive and Selective Fluorescein-Based Cu2+ Probe and Its Bioimaging in Cell

Copper is a vital trace metal in human body, which plays the significant roles in amounts of physiological and pathological processes. The application of copper-selective probe has attracted great interests from environmental tests to life process research, yet a few of sensitive Cu²⁺ tests based on on-site analysis have been reported. In this paper, a novel fluorescein-based fluorescent probe N4 was designed, synthesized, and characterized, which exhibited high selectivity and sensitivity to Cu²⁺ comparing with other metal ions in ethanol–water (1/1, v/v) solution. The probe N4 bonded with Cu²⁺ to facilitate the ring-opening, and an obvious new band at 525 nm in the fluorescence spectroscopy appeared, which could be used for naked-eye detection of Cu²⁺ within a broad pH range of 6–9. Meanwhile, a good linearity between the fluorescence intensity and the concentrations of Cu²⁺ ranged 0.1–1.5 eq. was observed, and the limit of detection of N4 to Cu²⁺ was calculated to be as low as 1.20 μm. In addition, the interaction mode between N4 and Cu²⁺ was found to be 1:1 by the Job's plot and mass experiment. Biological experiments showed that the probe N4 exhibited low biological toxicity and could be applied for Cu²⁺ imaging in living cells. The significant color shift associated with the production of the N4-Cu²⁺ complex at low micromolar concentrations under UV light endows N4 with a promising probe for field testing of trace Cu²⁺ ions.

Rational construction of deep-red fluorescent probe for rapid detection of HClO and its application in bioimaging and paper-based sensing

Hypochlorous acid (HClO), the core bactericidal substance of the human immune system, plays a vital role in many physiological and pathological processes in the human body. In this work, we designed and synthesized a novel deep-red fluorescent probe TCF-ClO for the determination of hypochlorous acid through theoretical analysis. The results showed that probe TCF-ClO exhibited excellent characteristics of long-wavelength emission (635 nm), fast response (< 1 min), and low detection limit (24 nM). In addition, it had been successfully used for imaging of HClO in living HeLa cells. More importantly, the TCF-ClO composited paper-based sensing material was successfully constructed. The RGB/gray value was obtained from a mobile phone and computer, which could achieve the quantitative detection of HClO, with a linear detection range of 0-50 μM and a detection limit of 1.09 μM (RGB mode)/3.38 μM (gray mode). The function of the paper-based sensor extended from qualitative to quantitative detection of HClO, and it is expected to become a portable device widely used in the environmental area.

Selective Thiocyanation and Aromatic Amination To Achieve Organized Annulation of Enaminone with Thiocyanate

A tandem insertion of thiocyanate to enamine was performed for the regioselective synthesis of multisubstituted benzoimidazo[2,1-b]thiazoles. This method was shown to be effective in addressing the issue of isomerization encountered in common strategies. With a change made to the leading group on the aniline fragment of enamine, the reaction achieved different transformations, thus enabling multisubstituted benzo[4,5]imidazo[2,1-b]thiazoles and thiazoles in satisfactory yields.

Fabrication of carbon dots for sequential on-off-on determination of Fe3+ and S2- in solid-phase sensing and anti-counterfeit printing

Glutathione and 2-aminopyridine are used as carbon sources to prepare carbon dots (CDs) by a one-step hydrothermal reaction. The results show that the average particle diameter of CDs is 8.64 nm with uniform size distribution and the fluorescence quantum yield is 13.62%. We further demonstrate that novel CDs possess highly selective sensing of Fe³⁺ from 0.2 to 200 μM with a low detection limit (0.194 μM). Meanwhile, the fluorescence of CDs can be repeated many times by the addition of S^2-. Moreover, the CDs are used for biological imaging of living cells with well cell penetrability and low toxicity. Furthermore, it is successfully applied for anti-counterfeiting and information encryption. More interestingly, it can be doped with hydrogel and filter paper to prepare solid-phase sensors exhibiting high sensitivity and fast response, demonstrating their tremendous potential for the simple, rapid, and low-cost monitoring of Fe³⁺ and S^2-.

Construction of DCM-based NIR fluorescent probe for visualization detection of H2S in solution and nanofibrous film

Hydrogen sulfide (H₂S) played crucial roles in biological processes and daily life, and the abnormal level of H₂S was associated with many physiological processes. In this paper, we designed and developed a dicyanomethylene-4H-chromene (DCM)-based near-infrared (NIR) fluorescent probe DCM-NO guided by theoretical calculation. The probe displayed excellent selectivity towards H₂S with a fast response time (3 min) and low detection limit (fluorescence 25.3 nM/absorption 6.61 nM) in Hela cells and real water samples. Furthermore, the probe-doped solid sensing materials (test strips and nanofibrous films) exhibited specific visualization of H₂S under ambient light or hand-held UV lamp, providing great potential for on-site and real-time application in environmental and biological systems.

Highly Stable Silica-Coated Bismuth Nanoparticles Deliver Tumor Microenvironment-Responsive Prodrugs to Enhance Tumor-Specific Photoradiotherapy

Radiosensitizers are agents capable of amplifying injury to tumor tissues by enhancing DNA damage and fortifying production of radical oxygen species (ROS). The use of such radiosensitizers in the clinic, however, remains limited by an insufficient ability to differentiate between cancer and normal cells and by the presence of a reversible glutathione system that can diminish the amount of ROS generated. Here, to address these limitations, we design an H₂O₂-responsive prodrug which can be premixed with lauric acid (melting point ∼43 °C) and loaded around the surface of silica-coated bismuth nanoparticles (BSNPs) for cancer-specific photoradiotherapy. Particularly, silica coating confers BSNPs with improved chemical stability against both near-infrared light and X-rays. Upon photothermal heating, lauric acid is melted to trigger prodrug release, followed by its transformation into p-quinone methide via H₂O₂ stimulation to irreversibly alkylate glutathione. Concurrently, this heat boosts tumor oxygenation and helps relieve the hypoxic microenvironment. Following sequential irradiation by X-rays, BSNPs generate plentiful ROS, which act in combination with these events to synergistically induce cell death via DNA breakage and mitochondria-mediated apoptosis pathways, ultimately enabling effective inhibition of tumor growth in vivo with high tumor specificity and reduced side effects. Collectively, this work presents a promising approach for the improvement of other ROS-responsive proalkylating agents, while simultaneously highlighting a robust nanosystem for combining these prodrugs with photoradiosensitizers to realize precision photoradiotherapy.

Recent Progress in Fluorescent Sensors for Drug-Induced Liver Injury Assessment

Drug-induced liver injury (DILI) is a persistent concern in drug discovery and clinical medicine. The current clinical methods to assay DILI by analyzing the enzymes in serum are still not optimal. Recent studies showed that fluorescent sensors would be efficient tools for detecting the concentration and distribution of DILI indicators with high sensitivity and specificity, in real-time, in situ, and with low damage to biosamples, as well as diagnosing DILI. This review focuses on the assessment of DILI, introduces the current mechanisms of DILI, and summarizes the design strategies of fluorescent sensors for DILI indicators, including ions, small molecules, and related enzymes. Some challenges for developing DILI diagnostic fluorescent sensors are put forward. We believe that these design strategies and challenges to evaluate DILI will inspire chemists and give them opportunities to further develop other fluorescent sensors for accurate diagnoses and therapies for other diseases.

Fluorescent sensing film decorated with ratiometric probe for visual and recyclable monitoring of Cu2

Specifically, visually, and quantitatively monitor copper ion (Cu²⁺) is critical in the area of biological and environmental detection. Herein, a ratiometric fluorescent probe with benzoxazole appended xanthenes skeleton was constructed and further employed to monitor Cu²⁺ in Hela cells, real water samples, and test strips. An easily distinguishable colorimetric (colorless to red) and fluorescence (green to red) change could be observed by naked eye under the portable UV lamp (365 nm) and the changes could be recovered by adding S^2-. Furthermore, electrospinning technique was employed to fabricate a probe composited fluorescent sensing film (PMMA) for realizing the visual and recyclable monitoring of Cu²⁺, indicating that the probe-composited fluorescent sensing film has great potential for on-site and naked-eye detection of Cu²⁺ in practical.

An ICT-based fluorescent probe guided by theoretical calculation for selectively mapping endogenous GSH in living cells

Glutathione (GSH) is one of the most essential bio-thiols to maintain the redox balance of organisms which is strongly associated with many physiological processes. Detecting the concentration and mapping the distribution of GSH in the living system is significant to study many related diseases. In this work, we have successfully constructed an ICT-based model to guide the design and synthesis of GSH specific fluorescent probe CF1. A serials spectroscopy test demonstrated that the response of CF1 towards GSH owned large stokes shift (~167 nm) and an excellent linear relationship (0-120 μM, R² = 0.9961). Furthermore, CF1 was successfully applied to image endogenous GSH in different cell lines with high sensitivity. This work is instructive for the oriented synthesis of ICT-based functional fluorescent probe and the further visualization of intracellular targets in the living system.

Imaging and Monitoring the Hydrogen Peroxide Level in Heart Failure by a Fluorescent Probe with a Large Stokes Shift

Heart failure is the terminal stage of many cardiovascular diseases and is considered to be closely related to oxidative stress. Early understanding of pathogenesis can greatly improve the treatment and reduce the mortality of heart disease. In this work, based on the analysis of coumarin derivates by theoretical calculations, we designed and synthesized a fluorescent probe BCO with a large Stokes shift (107 nm) and excellent selectivity toward H₂O₂ in a living system. The distribution of H₂O₂ in the heart and thoracic aorta tissues was imaged with the aid of the probe BCO, which demonstrated that the cellular H₂O₂ level is upregulated in heart failure. This work provides a useful tool, BCO, for the evaluation of cellular oxidative stress and to further understand the pathophysiology process of heart disease.

Precise Synthesis of GSH-Specific Fluorescent Probe for Hepatotoxicity Assessment Guided by Theoretical Calculation

Drug-induced hepatotoxicity is the main cause of acute liver injury, and its early diagnosis is indispensable in pharmacological and pathological studies. As a hepatotoxicity indicator, the GSH distribution in the liver could reflect the damage degree in situ. In this work, we have provided a theoretical design strategy to determine the generation of photo-induced electron transfer mechanism and achieve high selectivity for the target. After that, we precisely synthesized a novel near-infrared fluorescent probe BSR1 to specifically monitor endogenous GSH and hepatotoxicity in biosystem with a moderate fluorescent quantum yield (Φ = 0.394) and low detection limit (83 nM) under this strategy. Moreover, this mapping method for imaging GSH depletion in vivo to assay hepatotoxicity may provide a powerful molecular tool for early diagnosis of some diseases and contribute to assay hepatotoxicity for the development of new drugs. Importantly, this theoretical calculation-guided design strategy may provide an effective way for the precise synthesis of the target-specific fluorescent probe and change this research area from "trial-and-error" to concrete molecular engineering.

An efficient biosensor for monitoring Alzheimer's disease risk factors: modulation and disaggregation of the Aβ aggregation process

An efficient biosensor to monitor Alzheimer's disease risk factors and inhibit Alzheimer's disease by disaggregating Aβ aggregation.

Fluorescent probes guided by a new practical performance regulation strategy to monitor glutathione in living systems

A practical regulation strategy for the design of glutathione specific probes and their application in living systems.

Glutathione (GSH) plays an important role in the body's biochemical defense system, and the detection of GSH in a physiological system is an important tool for understanding redox homeostasis. Protection–deprotection strategies have proven to be the most reliable, among existing detection methods. However, the understanding of how various electronic and steric effects influence a probe's ability to recognize a substrate is still lacking. In this study, we have analyzed various substituent effects on a GSH probe template via theoretical calculations and constructed the performance regulation and control strategy for this kind of probe. We then developed a series of guided probes using eighteen different acrylic ester derivatives to mask the fluorescence of fluorescein. The optical performance differences between the guided probes strongly supported the applicability of our proposed guiding strategy. Moreover, the positively guided probes are excellent for imaging GSH distribution in living cells and mice.

Novel Fluorescein-Based Fluorescent Probe for Detecting H2S and Its Real Applications in Blood Plasma and Biological Imaging

A broad-spectrum fluorescent probe, which can be applied to monitoring H₂S in various biological systems, has been rationally designed and synthesized. This specific probe was applied to localize the endogenous H₂S in living Raw264.7 macrophage cells, HepG2 cells, and H9C2 cells. At the same time, the probe has successfully visualized CBS- and CSE-induced endogenous H₂S production and monitored CBS and CSE activity in H9C2 cells. This probe could serve as a powerful molecular imaging tool to further explore the physiological function and the molecular mechanisms of endogenous H₂S in living animal systems.

A novel approach to study the structure-property relationships and applications in living systems of modular Cu(2+) fluorescent probes

A series of Cu²⁺ probe which contains 9 probes have been synthesized and established. All the probes were synthesized using Rhodamine B as the fluorophore, conjugated to various differently substituted cinnamyl aldehyde with C=N Schiff base structural motif as their core moiety. The structure-property relationships of these probes have been investigated. The change of optical properties, caused by different electronic effect and steric effect of the recognition group, has been analyzed systematically. DFT calculation simulation of the Ring-Close and Ring-Open form of all the probes have been employed to illuminate, summarize and confirm these correlations between optical properties and molecular structures. In addition, biological experiment demonstrated that all the probes have a high potential for both sensitive and selective detection, mapping of adsorbed Cu²⁺ both in vivo and environmental microbial systems. This approach provides a significant strategy for studying structure-property relationships and guiding the synthesis of probes with various optical properties.

Novel 3,6-unsymmetrically disubstituted-1,2,4,5-tetrazines: S-induced one-pot synthesis, properties and theoretical study

18 unprecedented 3,6-unsymmetrically disubstituted-1,2,4,5-tetrazines were synthesized, and their spectral and electrochemical properties are studied. A systematic theoretical investigation based on DFT calculations was carried out.

Blood pressure reducing effects of piromelatine and melatonin in spontaneously hypertensive rats

BACKGROUND

Recently, widespread interest has grown regarding melatonin treatment of hypertension including its cardioprotective effects. Studies in rodents indicate that melatonin plays a role in the pathogenesis of hypertension in rats with metabolic syndrome. Piromelatine, a melatonin agonist, serotonin 5-HT-1A and 5-HT-1D agonist and serotonin 5-HT2B antagonist is a multimodal agent with sleep promoting, anti-diabetic, analgesic, anti-neurodegenerative, anxiolytic and antidepressant potential, currently in development for the treatment of insomnia.

AIM

In this report we assessed the effects of piromelatine and melatonin treatment on blood pressure in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats.

MATERIALS AND METHODS

Five groups of 12-wk-old rats (10/group) were treated for 5 weeks with a vehicle, piromelatine (5, 15 and 50 mg/kg BW) and melatonin (10 mg/kg BW) and an age-matched WKY control group. Systolic blood pressure (tail-cuff method) was measured weekly at 9:00 a.m. and at 9:00 p.m. The rats body weight, plasma glucose, insulin, triglyceride, adiponectin, total cholesterol, HDL and LDL/VLDL cholesterol were also measured.

RESULTS

Our results showed that both piromelatine and melatonin reduced SHR blood pressure significantly both during the morning and the evening. Piromelatine, but not melatonin, also reduced SHR body weight gain and both significantly decreased plasma glucose and insulin levels and increased adiponectin levels.

CONCLUSIONS

Piromelatine, similar to melatonin, has an antihypertensive effect and also attenuates body weight, improves metabolic profiles and might be useful in the treatment of hypertension and the metabolic syndrome.

Associated factors for HIV and syphilis infection among men who have sex with men only and men who have sex with both men and women in cities of China

Summary

The aims of this paper were to find out the status of HIV and syphilis infection and to examine the sexual behaviours between men who have sex with men only (MSM/M) and men who have sex with both men and women (MSM/W), as well as to determine the correlates for HIV and syphilis infection among MSM/M and MSM/W, respectively. Among 1693 MSM who participated in the study, the proportions of MSM/M and MSM/W were 82.1% and 17.9%, respectively. The prevalences of HIV infection were 7.0% in MSM/M and 6.6% in MSM/W and the prevalences of syphilis infection were 11.9% and 13.2%, respectively. Among the MSM/M subset, the correlates both for HIV and syphilis infection included having more sexual partners, and being receptive or both insertive and receptive for anal sex. Among the MSM/W subset, living in Chengdu was associated with HIV infection and using condoms inconsistently during anal sex was associated with syphilis infection. The findings of this survey call for interventions tailored according to the needs of different subsets of MSM.

Enhancement of manumycin A-induced apoptosis by methoxyamine in myeloid leukemia cells

Farnesyltransferase inhibitors (FTIs) are currently under investigation for leukemia treatment. We evaluated the FTI manumycin A (manumycin) in two myeloid leukemia cell lines (U937 and HL-60). Manumycin induced nitric oxide production and apoptosis of the leukemia cells. Nitric oxide or other reactive oxygen species may induce oxidative DNA damage, and the number of apurinic sites increased after manumycin treatment, which was reversed by concurrent treatment with N-acetyl-L-cysteine. Since repair of DNA damage is important to cell survival, we hypothesized that methoxyamine, an inhibitor of base-excision repair, would enhance the antineoplastic effect of manumycin. The combination of manumycin and methoxyamine resulted in enhanced apoptosis by six criteria increased annexin V binding, release of mitochondrial cytochrome c into the cytosol, activation of caspase-9, activation of caspase-3, specific cleavage of poly-adenosyl ribose polymerase, and increase in the sub-G1 cell cycle fraction. The drug combination enhanced inhibition on the soft agar clonogenic assay and on the formazan dye cell viability assay. The effects of manumycin or manumycin plus methoxyamine on apoptosis were blocked by N-acetyl-L-cysteine, and partially by nitric oxide synthase inhibitors or scavenger of peroxide. We conclude that methoxyamine enhances manumycin-induced apoptosis in myeloid leukemia cells.

Factors contributing to troponin exchange in myofibrils and in solution

The troponin complex in a muscle fiber can be replaced with exogenous troponin by using a gentle exchange procedure in which the actin-tropomyosin complex is never devoid of a full complement of troponin (Brenner et al. (1999) Biophys J 77: 2677-2691). The mechanism of this exchange process and the factors that influence this exchange are poorly understood. In this study, the exchange process has now been examined in myofibrils and in solution. In myofibrils under rigor conditions, troponin exchange occurred preferentially in the region of overlap between actin and myosin when the free Ca2+ concentration was low. At higher concentrations of Ca2+, the exchange occurred uniformly along the actin. Ca2+ also accelerated troponin exchange in solution but the effect of S1 could not be confirmed in solution experiments. The rate of exchange in solution was insensitive to moderate changes in pH or ionic strength. Increasing the temperature resulted in a two-fold increase in rate with each 10 degrees C increase in temperature. A sequential two step model of troponin binding to actin-tropomyosin could simulate the observed association and dissociation transients. In the absence of Ca2+ or rigor S1, the following rate constants could describe the binding process: k1 = 7.12 microM(-1) s(-1), k(-1) = 0.65 s(-1), k2 = 0.07 s(-1), k(-2) = 0.0014 s(-1). The slow rate of detachment of troponin from actin (k(-2)) limits the rate of exchange in solution and most likely contributes to the slow rate of exchange in fibers.

Molecular basis for the effect of lipid lowering drugs on growth factors after de-endothelialization

OBJECTIVE

To study the mechanism and effect of lipid lowering drugs in arresting the development of arterial restenosis after angioplasty.

METHODS

De-endothelialization injury of rabbit aortae, common iliac and femoral arteries using balloon angioplasty and the expression of growth factors such as platelet derived growth factor-B (PDGF-B), transforming growth factor beta-1 (TGF beta-1), and fibroblast growth factors (bFGF) were investigated. Total serum cholesterol (TC) and triglycerides (TG) were analyzed during and after the treatment using either simvastatin combined with gemfibrozil or simvastatin alone for 6 weeks.

RESULTS

Serum total cholesterol and triglycerides were only slightly to moderately increased after high cholesterol ration intake lasting for 6 weeks in rabbits of two therapeutic groups (simvastatin plus gemfibrozil or only simvastatin). A positive correlation was found between TC and intimal/medial ratio (r = 0.5873, P < 0.05). PDGF-B detected by immuno-histochemistry and RT-PCR analysis showed that the release of PDGF-B was inhibited by simvastatin and gemfibrozil after de-endothelialization. RT-PCR analysis showed that TGF beta-1 was increased in the neointima in two treatment groups but no definite change was seen in the mRNA of bFGF in the smooth muscle cell (SMC) of the balloon-injured arteries even under lipid lowering drug treatment.

CONCLUSION

In addition to the lipid lowering effect, both simvastatin and gemfibrozil also influence the release of PDGF-Band TGF-1 in the neointima after de-endothelialization.

Development of serine protease inhibitors displaying a multicentered short (<2.3 A) hydrogen bond binding mode: inhibitors of urokinase-type plasminogen activator and factor Xa

Novel scaffolds that bind to serine proteases through a unique network of short hydrogen bonds to the catalytic Ser195 have been developed. The resulting potent serine protease inhibitors were designed from lead molecule 2-(2-hydroxyphenyl)1H-benzoimidazole-5-carboxamidine, 6b, which is known to display several modes of binding. For instance, 6b can recruit zinc and bind in a manner similar to that reported by bis(5-amidino-2-benzimidazolyl)methane (BABIM) (Nature 1998, 391, 608-612).(1) Alternatively, 6b can bind in the absence of zinc through a multicentered network of short (<2.3 A) hydrogen bonds. The lead structure was optimized in the zinc-independent binding mode toward a panel of six human serine proteases to yield optimized inhibitors such as 2-(3-bromo-2-hydroxy-5-methylphenyl)-1H-indole-5-carboxamidine, 22a, and 2-(2-hydroxybiphenyl-3-yl)-1H-indole-5-carboxamidine, 22f. Structure-activity relationships determined that, apart from the amidine function, an indole or benzimidazole and an ortho substituted phenol group were also essential components for optimal potency. The affinities (K(i)) of 22a and 22f, for example, bearing these groups ranged from 8 to 600 nM toward a panel of six human serine proteases. High-resolution crystal structures revealed that the binding mode of these molecules in several of the enzymes was identical to that of 6b and involved short (<2.3 A) hydrogen bonds among the inhibitor hydroxyl oxygen, Ser195, and a water molecule trapped in the oxyanion hole. In summation, novel and potent trypsin-like serine protease inhibitors possessing a unique mode of binding have been discovered.

[Activation of NF-kappa B and its effect on induction of platelet-derived growth factor-B transcription by angiotensin II in ECV304 cell line]

OBJECTIVES

The renin-angiotensin system may contribute to the pathogenesis of atherosclerosis. The transcription factor nuclear factor-kappa B (NF-kappa B) participates in most signal pathways involved in the inflammatory process. In this project the effect of angiotensin II (Ang II) on NF-kappa B activation and the promotion of PDGF-B mRNA expression in human endothelial cell line ECV304 was studied.

METHODS

Electrophoretic mobility shift assay, immunofluorescence and immunoelectronic microscope techniques, including confocal microscopy and gold particle labelled electronic microscopy were applied to investigate the mechanism by which Ang II activates NF-kappa B, ECV304 cells were transiently transfected with an NF-kappa B/luciferase reporter gene and catalytically inactive NIK, IKK alpha, IKK beta mutants respectively. Northern blot was carried out to detect PDGF-B mRNA.

RESULTS

By the findings of immunofluorescence confocal microscopy, immunoelectronic microscopy and Northern blot, Ang II was effective in stimulating NF-kappa B activation and there was definited cytoplasmic-to-nuclear translocation of NF-kappa B subunits p50 and p65 and overexpression of PDGF-B mRNA expression. Over-expression of the transiently transfected IKK alpha-KM, IKK beta-KM and NIK-KM mutant genes enabled to block the reporter gene activation induced by ang II.

CONCLUSION

Ang II is effective to activate NF-kappa B through a pathway dependent on NIK, IKK alpha and IKK beta, and induces PDGF-B transcription in the endothelial cell line ECV304.

[Influence of a G/A substitution at -75 bp promoter region of apolipoprotein A I gene and wine consumption on the plasma apolipoprotein A I levels in Yi and Han Chinese]

OBJECTIVE

To study the influence of a common polymorphism of the human apolipoprotein A I gene promoter at a position of -75 bp upstream of the transcription start site and wine consumption on plasma lipid levels.

METHODS

742 healthy Yi and Han healthy subjects all above 15 years old to be the total population which was divided into three samples, namely, Yi-farmer sample, Yi-emigrant sample and Han-resident sample for this study. Estimations of plasma lipids and apolipoproteins were carried on through an auto-analyzer. Genetic DNA was prepared from the frozen blood clot using Triton x-100 lysis technique. Amplification of a 432 bp fragment of the apoA I gene promoter was performed via the PCR, followed by restriction digestion, electrophoresis and identification of the genotypes involved. Data analysis was done at last.

RESULTS

Four groups of alcohol consumption were defined: the non-drinkers, 1 - 25 g alcohol intake/day, 26 - 75 g alcohol/day and > 75 g alcohol/day. A tendency of a mild persistent elevation of plasma HDL-C and apoA I was noticed corresponding to an increase of the amount of alcohol intake, and with no evidence of threshold effect observed in the samples of both the Yi-farmers and the Han people. Similar phenomenon was obtained in the sample of Yi-emigrants, but no statistical significance. The frequencies of the A allele of all 3 samples were similar. In Han and Yi-emigrant samples, the drinkers with genotypes of GG had a higher plasma HDL-C and apoA I level than that of the non-drinkers with the same genotypes. Drinkers with A allele had a lower plasma HDL-C and apoA I level than that of drinkers without A allele, and the non-drinkers with A allele had a higher levels of apoA I than of non-drinkers with genotypes of GG. It is estimated that 18% of the variability of plasma apoA I level could be explained by the G/A polymorphism in non-drinkers of Yi-emigrants (F = 8.94, P < 0.01).

CONCLUSIONS

Current data suggest that a moderate alcohol consumption or a G to A substitution could make a lower incidence of CHD, but the beneficial effect of one will be negated by the other when both factors occur simultaneously. This finding is seemed valuable for a further study on the effect of the environmental factor or genetic factor in effecting the plasma apoA I level afterwards.

Suppression of induced atherosclerosis in h-apo AI transgenic mice by overexpression of human apo AI in the aortic wall

OBJECTIVES

To investigate the inhibitory effect of expressed human apolipoprotein AI (h-apo AI) and high density lipoprotein (HDL) on atherosclerosis development in transgenic mice, and cultivation of smooth muscle cells isolated from the aortic wall of transgenic mice that are able to produce human apo AI in vitro.

METHODS

Both h-apo AI transgenic mice and normal C57 mice were fed with either a regular chow or a high-fat diet containing 5% pork lard, 1.25% cholesterol and 0.25% sodium cholate for 14 or 24 weeks respectively. Human apo AI mRNA were detected by Northern blot. Plasma apo AI levels were measured using a radio-immuno-diffusion assay, and plasma lipid levels were measured using a colorimetric assay. Image analysis was performed in order to quantify the fatty streak areas stained with oil red O. In addition, smooth muscle cells isolated from the media layer of the aortic wall of h-apo AI transgenic mice were cultured for the detection of human apo AI produced.

RESULTS

Higher levels of h-apo AI mRNA were found in liver, small intestine, kidneys and aortae in transgenic mice than in the controls all on a high-fat diet. The transgenic mice had an increased level of serum apo AI and HDL-cholesterol and the fatty streak area counted at the aortic sinus was approximately 5-fold less in the transgenic mice after feeding with a high fat ration, particularly after 24 weeks. SMC isolated from the transgenic mice aortae were cultivated and able to express h-apo AI mRNA and its related protein.

CONCLUSION

Elevation of h-apo AI and HDL in serum and aortic wall of the transgenic mice has a remarkably inhibitory effect on the development of experimental atherosclerosis.

Interaction of alcohol and the G to a substitution at the promoter region of the apolipoprotein AI gene in determining plasma apolipoprotein AI levels in Yi and Han Chinese

OBJECTIVE

To investigate the influence on plasma lipid levels of alcohol and a common polymorphism in the human apolipoprotein AI gene promoter at a position 75 bp upstream of the transcription start site.

METHODS

For this study, 742 healthy Yi and Han subjects all above 15 years old formed the total population which was divided into three groups: the Yi-farmer group, the Yi-emigrant group and the Han-resident group. All estimates of plasma lipids and apolipoproteins were performed using an auto-analyzer. Genetic DNA was prepared from the blood clots using the Triton X-100 lysis technique. Amplification of a 432 bp fragment of the apoAI gene promoter was performed using PCR followed by restriction digestion, electrophoresis and identification of the genotypes involved.

RESULTS

The samples were divided on the basis of alcohol consumption: non-drinkers, 1-25 g/day, 26-75 g/day and > 75 g/day. Comparing the four alcohol consumption groups, plasma HDLC and apoAI levels were increased as the alcohol consumption increased with no evidence of threshold effects in the Yi-farmers and the Han people groups. A similar association was found in the Yi-emigrant group, but was not statistically significant. The frequencies of the A allele in the three populations were similar, and no significant difference of lipid and apolipoprotein levels was found between subjects with and without the A allele in the three populations. But, in Han and Yi-emigrant samples, the drinkers with the GG genotype had higher plasma HDLC and apoAI levels than non-drinkers with the same genotype, while the drinkers with the A allele had lower plasma HDLC and apoAI levels than drinkers without the A allele. Non-drinkers with the A allele had higher levels of apoAI than non-drinkers with GG genotypes. It was estimated that 18% of the variability of plasma apoAI level could be explained by the G to A polymorphism in non-drinkers of Yi-emigrants (F = 8.94, P < 0.01).

CONCLUSIONS

The present data suggest that moderate alcohol consumption and the G to A substitution could lower the risk of coronary heart disease (CHD), but the beneficial effects of one will be negated by the other.

[Inhibition of monocytes adhesion to the intima of arterial wall by local expression of antisense monocyte chemotactic protein-1]

OBJECTIVE

To study the mechanism of monocyte recruitment in atherogenesis and to clarify the effect of monocyte chemotactic protein-1 (MCP-1) in this process.

METHODS

Femoral arteries isolated from the rabbits which had been fed with a high cholesterol diet and locally perfused with MM-LDL within the artery beforehand, were used as the models. Antisense MCP-1cDNA was transferred into the arterial wall by injecting recombinant LNCX-anti-MCP-1/liposomal complex in the femoral sheath and the periarterial tissue.

RESULTS

Expression of antisense MCP-1 mediated by recombinant LNCX plasmid/lipsomal complex gene transfer enabled to inhibit MCP-1 gene expression and adhesion of monocyte to the intima.

CONCLUSION

MCP-1 plays an important role on the recruitment of monocytes in the arterial wall, which provides a potential clue in developing a gene therapy project for the prevention and treatment of atherogenesis.

Inhibition of intimal lipid deposition in human apolipoprotein A1 transgenic mice

1. Southern blot confirmed the emergence of the human apolipoprotein A1 (h-apoA1) gene (four to 15 copies) in newborn transgenic mice. The inheritance pattern of h-apoA1 transgene in three generations of progeny was compatible with a single autosomal integration site. 2. Northern blot showed h-apoA1 mRNA expressed mainly in liver, kidney and aorta. The total plasma apoA1 (murine plus human) level was significantly increased to 58 and 118 in transgenic mice without or under zinc induction, respectively. The majority was h-apoA1. Plasma lecithin:cholesterol acyltransferase activity was positively correlated with h-apoA1 levels in transgenic mice (r = 0.43; P < 0.01). 3. After a high cholesterol intake for 14 weeks, the incidence of fatty streak at the aortic sinus was 40% in transgenic mice and 80% in controls. Expression of platelet-derived growth factor-B, c-myc and c-fos proteins was much weaker in smooth muscle cells at the aortic sinus in transgenic mice.

[Cloning whole length cDNA of related genes responsible for smooth muscle cells proliferation in atherogenesis and study on its function]

OBJECTIVE

To clone whole length cDNA of the related genes responsible for vascular smooth muscle cell (SMC) proliferation in atherogenesis, and to study its function.

METHODS

ox-LDL was added as a stimulant to the SMC culture medium. Subtractive library was established using subtractive hybridization technique in order to clone the related genes fragments. With the whole length cDNA library established, the whole length cDNA of the related gene was cloned. The protein expressed was studied.

RESULTS

4 new gene fragments and one whole length cDNA were cloned. The new cloned gene is able to express a protein of about 44000 daltons and closely related to the activity of ox-LDL.

CONCLUSIONS

The new cloned gene is considered responsible for SMC proliferation.

[Morphometric study of inflammatory cells and smooth muscle cells in coronary plaques and their relation with plaque stability]

OBJECTIVE

To compare the content of inflammatory cells and smooth muscle cells in stable and unstable coronary plaques in order to clarify the role of these cells in the vulnerability of plaques.

METHODS

Hearts from 12 postmortem acute myocardial infarction cases were studied. The epicardial coronary arteries were dissected en bloc, fixed, decalcified, cut at 4 mm intervals and routinely processed for HE sections. 163 stable plaques (with no or only little lipid core) and 163 unstable plaques (with lipid core size > 40% of plaque area) were studied immunohistochemically using monoclonal antibodies specific for macrophages (CD68), T lymphocytes (UCHL-1) and smooth muscle cells (actin). Computor aided planimetry was used to measure the positive area of different cells.

RESULTS

The content of macrophage and T lymphocytes in unstable plaques were significantly higher than that in stable plaques (P < 0.05).

CONCLUSIONS

Stable plaques and unstable plaques not only had different lipid core size but also had different inflammatory cell and smooth muscle cell content. The larger the lipid core and the more macrophages and T lymphocytes in the fibrous cap, the more unstable the plaque. The lipid core and inflammatory cells (including macrophages and T lymphocytes) are the two major determinants of the vulnerability of coronary plaques.

Minimally modified low-density lipoprotein induces monocyte chemotactic protein-1 expression in vivo and a novel model for monocyte adhesion to arterial intima

OBJECTIVE

To test whether minimally modified low-density lipoprotein (MM-LDL) can stimulate the arterial cells expressing MCP-1 in vivo and thus induce monocyte adherence to endothelium.

METHODS

An animal model was constructed to study the function of MM-LDL in vivo. MM-LDL (600 micrograms/ml) was perfused into a segment of the femoral artery of rabbits (both ends of which were occluded with removable ligatures). After exposure to MM-LDL for 2 h, the arterial segments were taken out 6 or 18 h later. The arteries were subjected to in situ hybridization with 35S-labeled antisense monocyte chemotactic protein-1 (MCP-1) RNA probe and processed for scanning electron microscopy.

RESULTS

The expression of MCP-1 mRNA of the arterial endothelial cells and smooth muscle cells were increased by 60% and 90% 6 h after perfusion and had a 3.2 folds and 1.6 folds increase 18 h after perfusion respectively as compared with control (arteries perfused with saline). There was also apparent monocyte adherence to the endothelium observed by scanning electron microscopy.

CONCLUSION

MM-LDL can stimulate vascular cells in expressing MCP-1 mRNA and enhance monocyte adherence to endothelium in vivo.

[The modulation of collagen synthesis and expressions of type I and III collagen mRNAs in aorta smooth muscle cell by PDGF and heparin]

OBJECTIVE

The effect of platelet derived growth factor (PDGF) and heparin on the modulation of human aorta smooth muscle cell(hASMC) proliferation, collagen synthesis, expressions of type I and III collagen mRNAs as well as transforming growth factor-beta (TGF-beta) mRNA were investigated.

METHODS

3H-TdR and 3H-proline incorporation and Northern blot analysis were done. 3H-TdR and 3H-proline incorporation was statistically analyzed with t test among different experimental groups.

RESULTS

In comparison to the control group, PDGF possessed the ability in promoting markedly the DNA synthesis (3H-TdR incorporation: PDGF group vs control, P < 0.01), synthesis and secretion of collagen protein (3H-proline incorporation of SMC and medium: PDGF group vs control, P < 0.01), expressions of type I and type III collagen mRNAs, and transforming growth factor mRNA in hASMC. Whereas heparin significantly decreased the DNA synthesis (heparin group vs control, P < 0.01), synthesis and secretion of collagen protein (heparin group vs control, P < 0.01) of hASMC in vitro. Heparin also inhibited the promoting effect of PDGF on DNA synthesis, the synthesis and secretion of collagen protein, and reduced the up-regulation of expressions of type I and type III collagen mRNAs as well as TGF-beta mRNA that stimulated by PDGF.

CONCLUSIONS

PDGF could promote the collagen synthesis through upregulating type I and type III collagen mRNA expressions while heparin just inhibiting SMC DNA and collagen synthesis effected in the way of anti-atherosclerosis.

Calcium binding to the regulatory domain of skeletal muscle troponin C induces a highly constrained open conformation

We have used fluorescence resonance energy transfer to investigate the conformation of the apo and calcium-loaded states of the regulatory N-terminal domain of full-length troponin C mutants from skeletal muscle. The mutants studied each contained a single tryptophan residue (position 22 or 90) and a single cysteine residue (position 52 or 101). The intrinsic fluorophore in each mutant served as an energy donor and the cysteine was conjugated to the acceptor probe 5-(iodoacetamidoethyl)amino-naphthalene-1-sulfonic acid. The distributions of two intersite distances (between residues 22 and 52, and residues 90 and 52) were broad in the apo state, indicative of considerable structural dynamics. These distributions were shifted to longer distances and considerably sharpened in the calcium-loaded state. The shifts to longer distances by 8 to 11 A indicate a calcium-induced opening of the N-terminal domain conformation. The transition of the troponin C structure from a closed conformation to an open conformation is accompanied by a substantial reduction of structural fluctuations that dominate in the apo structure as evidenced from the large decrease of the widths of the distributions. This highly constrained open conformation is required as part of the structural basis to facilitate productive interaction between troponin C and troponin I to trigger contraction in skeletal muscle.

[The effect of expressed human apolipoprotein AI on plasma high density lipoprotein level in transgenic mice]

OBJECTIVE

To study the regulation of human apolipoprotein AI(h-apo AI) gene expression and its role in high density lipoprotein (HDL) metabolism.

METHODS

Transgenic C57BL/6 mice established in this laboratory with human apoAI gene containing mouse metallothionein-I(MT-I) promoter were used for investigation.

RESULTS

Southern blot identified the presence of 4-15 copies of h-apo AI gene in the transgenic mice. Northern blot showed that human apo AI mRNA was expressed mainly in the liver and kidneys, and the high level of h-apo AI mRNA was obtained in liver, kidneys and small intestine after Zinc(Zn) induction. Total Plasma apoAI Level in transgenic mice was significantly increased than that in the controls, and a high h-apoAI level was detected in the transgenic mice (46% increased after Zn induction). Additionally, total and HDL cholesterol levels were noticed to be highly increased to 47% before and 103% after Zn induction in the transgenic mice comparing to that of the controls. The plasma HDL and h-apoAI levels were significantly correlated (r = 0.85, P < 0.01) in the transgenic mice.

CONCLUSION

Apo AI has a profound effect on regulating HDL levels in the transgenic mice. This animal model is considered appropriate for studying the effect of apoAI on lipid metabolism and the mechanism combating atherogenesis.