[Network Meta-analysis of Chinese medicine injections for activating blood and resolving stasis in adjuvant treatment of acute ischemic stroke]

Network Meta-analysis was employed to compare the efficacy of Chinese medicine injections for activating blood and resolving stasis combined with conventional western medicine in the treatment of acute ischemic stroke and the effects on platelet aggregation rate, fibrinogen(FIB), and hypersensitive C-reactive protein(hs-CRP), with a view to providing evidence-based medicine reference for clinical medication. CNKI, Wanfang, VIP, SinoMed, PubMed, Web of Science, Cochrane Library, and EMbase were searched for randomized controlled trial(RCT) on the treatment of acute ischemic stroke with Salvia Miltiorrhiza Ligustrazine Injection, Danhong Injection, Shuxuetong Injection, Xueshuantong Injection, Shuxuening Injection, Safflower Yellow Pigment Injection, and Ginkgo Diterpene Lactone Meglumine Injection combined with conventional western medicine. The retrieval time was from database inception to March 18, 2023. The articles were extracted by two researchers and their quality was evaluated. R 4.2.2 was used for network Meta-analysis. A total of 87 RCTs involving 8 580 patients were included. Network Meta-analysis showed that, in terms of reducing National Institutes of Health stroke scale(NIHSS) scores, the surface under the cumulative ranking curve(SUCRA) showed the order of Xueshuantong Injection + conventional western medicine(88.7%) > Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine(73.7%) > Shuxuetong Injection + conventional western medicine(69.7%) > Shuxuening Injection + conventional western medicine(51.8%) > Danhong Injection + conventional western medicine(43.7%) > Safflower Yellow Pigment Injection + conventional western medicine(36.8%) > Ginkgo Diterpene Lactone Meglumine Injection + conventional western medicine(35.3%) > conventional western medicine(1.7%). In terms of improving clinical total effective rate, SUCRA showed the order of Danhong Injection + conventional western medicine(63.0%) > Shuxuening Injection + conventional western medicine(59.0%) > Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine(58.9%) > Safflower Yellow Pigment Injection + conventional western medicine(57.1%) > Xueshuantong Injection + conventional western medicine(56.8%) > Shuxuetong Injection + conventional western medicine(54.6%) > Ginkgo Diterpene Lactone Meglumine Injection + conventional western medicine(50.5%) > conventional western medicine(0.03%). In terms of improving Barthel index, SUCRA showed the order of Danhong Injection + conventional western medicine(84.7%) > Shuxuetong Injection + conventional western medicine(72.4%) > Safflower Yellow Pigment Injection + conventional western medicine(61.6%) > Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine(44.6%) > Ginkgo Diterpene Lactone Meglumine Injection + conventional western medicine(43.2%) > Shuxuening Injection + conventional western medicine(42.2%) > conventional western medicine(1.4%). In terms of reducing platelet aggregation rate, SUCRA showed the order of Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine(82.4%) > Shuxuetong Injection + conventional western medicine(81.6%) > Ginkgo Diterpene Lactone Meglumine Injection + conventional western medicine(40.7%) > Danhong Injection + conventional western medicine(37.3%) > conventional western medicine(8.0%). In terms of reducing FIB, SUCRA showed the order of Danhong Injection + conventional western medicine(81.0%) > Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine(71.9%) > Ginkgo Diterpene Lactone Meglumine Injection + conventional western medicine(70.0%) > Shuxuetong Injection + conventional western medicine(46.7%) > Xueshuantong Injection + conventional western medicine(22.6%) > conventional western medicine(8.7%). In terms of reducing hs-CRP, SUCRA showed the order of Shuxuening Injection + conventional western medicine(89.9%) > Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine(78.8%) > Ginkgo Diterpene Lactone Meglumine Injection + conventional western medicine(52.4%) > Danhong Injection + conventional western medicine(47.6%) > Xueshuantong Injection + conventional western medicine(43.5%) > Shuxuetong Injection + conventional Western medicine(35.6%) > conventional western medicine(2.3%). The results indicated that Xueshuantong Injection + conventional western medicine, Danhong Injection + conventional western medicine, and Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine ranked the top three. Xueshuantong Injection + conventional western medicine had the best effect on reducing NIHSS scores. Danhong Injection + conventional western medicine showed the best performance of improving clinical total effective rate, improving Barthel index, and reducing FIB in the blood. Salvia Miltiorrhiza Ligustrazine Injection + conventional western medicine had the best effect on reducing platelet aggregation rate in the blood. Shuxuening Injection + conventional western medicine had the best effect on reducing hs-CRP. However, more high-quality RCTs are needed for verification in the future to provide more reliable evidence-based medical reference.

Long non-coding RNA TFAP2A-AS1 plays an important role in oral squamous cell carcinoma: research includes bioinformatics analysis and experiments

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the most common neck and head malignancies, and the prognosis is not good. Studies shown that the long non-coding RNA (lncRNA) TFAP2A-AS1 is involved in the progression of multiple cancers. However, the role of lncRNA TFAP2A-AS1 in OSCC remains unclear. We aimed to explore the functions and expression in OSCC.

METHODS

The lncRNA profiles for OSCC patients were acquired from the TCGA. Based on these data, the data mining of TFAP2A-AS1 in patients with OSCC were performed. The functions of TFAP2A-AS1 were determined by bioinformatics analysis. The expression and roles in cell growth were tested by RT-qPCR and MTS assay. Cell invasion and migration were tested by wound healing and transwell assays.

RESULTS

The consequences displayed that TFAP2A-AS1 was upregulated in the TCGA datasets. The expression of TFAP2A-AS1 was higher in OSCC samples. Bioinformatics analysis shown that TFAP2A-AS1 might be associated with the P53 signaling pathway. Cell culture experiments indicated that deficiency of TFAP2A-AS1 inhibited cell growth, invasion, and migration, and overexpression of it could opposite results in SCC-25 cells.

CONCLUSION

The results suggested that TFAP2A-AS1 was overexpressed in OSCC cells, which could facilitate OSCC cell proliferation, migration, and invasion.

Improvements of PKU PMECRIS for continuous hundred hours CW proton beam operation

In order to improve the source stability, a long term continuous wave (CW) proton beam experiment has been carried out with Peking University compact permanent magnet 2.45 GHz ECR ion source (PKU PMECRIS). Before such an experiment a lot of improvements and modifications were completed on the source body, the Faraday cup and the PKU ion source test bench. At the beginning of 2015, a continuous operation of PKU PMECRIS for 306 h with more than 50 mA CW beam was carried out after success of many short term tests. No plasma generator failure or high voltage breakdown was observed during that running period and the proton source reliability is near 100%. Total beam availability, which is defined as 35-keV beam-on time divided by elapsed time, was higher than 99% [S. X. Peng et al., Chin. Phys. B 24(7), 075203 (2015)]. A re-inspection was performed after another additional 100 h operation (counting time) and no obvious sign of component failure was observed. Counting the previous source testing time together, this PMECRs longevity is now demonstrated to be greater than 460 h. This paper is mainly concentrated on the improvements for this long term experiment.

Duty factor variation possibility from 1% to 100% with PKU microwave driven Cs-free volume H⁻ sources

Microwave driven cesium-free volume H(-) sources, that have the ability to deliver tens of mA H(-) at 35 keV both in CW and 10% duty factor (100 Hz/1 ms), were developed at Peking University (PKU) [S. X. Peng et al., in Proceeding of IPAC 2015, WEPWA027, Richmond, Virginia, USA, 3-8 May 2015]. Recently, special efforts were paid on the investigation of duty factor variation possibility from 1% to 100% with them. Most of the experiments were carried out with a pulsed length (τ) of 1 ms and different intervals of 99 ms, 49 ms, 39 ms, 29 ms, 19 ms, 9 ms, 4 ms, 2 ms, 1 ms, 0.5 ms, and 0 ms, respectively. Other experiments were focused on CW operation and fixed duty factor of 1%. Experimental results prove that PKU H(-) sources can deliver tens of mA H(-) at duty factor from 1% to 100%. The RF power efficiency increases steadily with the increasing of duty factor from 1% to CW at a fixed pulsed length. Under a given duty factor and pulsed length, RF power efficiency keeps constant and the H(-) current increases with RF power linearly. Details will be presented in the paper.

Study on space charge compensation in negative hydrogen ion beam

Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H(+) beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H(-) beam from a 2.45 GHz microwave driven H(-) ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

Handling radiation generated during an ion source commissioning

Radiation is an important issue, which should be carefully treated during the design and commissioning of an ion source. Measurements show that X-rays are generated around the ceramics column of an extraction system when the source is powered up to 30 kV. The X-ray dose increases greatly when a beam is extracted. Inserting the ceramic column into a metal vacuum box is a good way to block X-ray emission for those cases. Moreover, this makes the online test of an intense H(+) ion beam with energy up to 100 keV possible. However, for deuteron ion source commissioning, neutron and gamma-ray radiation become a serious topic. In this paper, we will describe the design of the extraction system and the radiation doses of neutrons and gamma-rays measured at different D(+) beam energy during our 2.45 GHz deuteron electron cyclotron resonance ion source commissioning for PKUNIFTY (PeKing University Neutron Imaging FaciliTY) project at Peking University.

Commissioning and operation of the deuteron injector for PKUNIFTY project

PKUNIFTY (PeKing University Neutron Imaging FaciliTY), a thermal neutron imaging facility based on a 2 MeV RFQ accelerator, has been constructed at Peking University. Its deuteron injector, which consists of a 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) deuteron ion source and a two-solenoid low energy beam transport (LEBT), aims at producing and delivering 50 mA, 50 keV deuteron beam with a duty factor of 10% (1 ms, 100 Hz). In the preliminary tests of RFQ accelerator, the ECR ion source and LEBT are required to operate at various duty factors (from 1% to 10%). The deuteron ion source has been tested with different pulse widths for this reason. In order to optimize the transmission parameters, the beam current at the exit of RFQ as a function of solenoids tuning and steering magnets tuning are carefully studied. The beam emittance at the entrance of RFQ has been measured with space charge compensation by different argon gas (RG) pressure from 1.6 × 10(-4) Pa to 4.7 × 10(-3) Pa. The measuring results show the best compensating pressure is 3.5 × 10(-3) Pa with a minimal normalized rms emittance of 0.12 pi mm mrad. During the commissioning, we found the purity of deuteron gas is an important factor which severely affects ECR discharge and plasma intensity inside the ion source chamber. The detailed experimental results obtained during the commissioning are discussed in this paper.

Plasma studies of the permanent magnet electron cyclotron resonance ion source at Peking University

At Peking University (PKU) we have developed several 2.45 GHz Permanent Magnet Electron Cyclotron Resonance ion sources for PKUNIFTY, SFRFQ, Coupled RFQ&SFRFQ, and Dielectric-Wall Accelerator (DWA) projects (respectively, 50 mA of D(+), 10 mA of O(+), 10 mA of He(+), and 50 mA of H(+)). In order to improve performance of these ion sources, it is necessary to better understand the principal factors that influence the plasma density and the atomic ion fraction. Theoretical analysis about microwave transmission and cut-off inside the discharge chamber were carried out to study the influence of the discharge chamber diameters. As a consequence, experimental studies on plasma density and ion fraction with different discharge chamber sizes have been carried out. Due to the difficulties in measuring plasma density inside the discharge chamber, the output beam current was measured to reflect the plasma density. Experimental results show that the plasma density increases to the maximum and then decreases significantly as the diameter changed from 64 mm to 30 mm, and the atomic ion fraction has the same tendency. The maximum beam intensity was obtained with the diameter of 35 mm, but the maximum atomic ion fraction with a diameter of 40 mm. The experimental results are basically accordant with the theoretical calculation. Details are presented in this paper.

Intense beams from gases generated by a permanent magnet ECR ion source at PKU

An electron cyclotron resonance (ECR) ion source is designed for the production of high-current ion beams of various gaseous elements. At the Peking University (PKU), the primary study is focused on developing suitable permanent magnet ECR ion sources (PMECRs) for separated function radio frequency quadrupole (SFRFQ) accelerator and for Peking University Neutron Imaging Facility. Recently, other kinds of high-intensity ion beams are required for new acceleration structure demonstration, simulation of fusion reactor material irradiation, aviation bearing modification, and other applications. So we expanded the ion beam category from O(+), H(+), and D(+) to N(+), Ar(+), and He(+). Up to now, about 120 mA of H(+), 83 mA of D(+), 50 mA of O(+), 63 mA of N(+), 70 mA of Ar(+), and 65 mA of He(+) extracted at 50 kV through a φ 6 mm aperture were produced by the PMECRs at PKU. Their rms emittances are less than 0.2 π mm mrad. Tungsten samples were irradiated by H(+) or He(+) beam extracted from this ion source and H∕He holes and bubbles have been observed on the samples. A method to produce a high intensity H∕He mixed beam to study synergistic effect is developed for nuclear material irradiation. To design a He(+) beam injector for coupled radio frequency quadruple and SFRFQ cavity, He(+) beam transmission experiments were carried out on PKU low energy beam transport test bench and the transmission was less than 50%. It indicated that some electrode modifications must be done to decrease the divergence of He(+) beam.

A 2.45 GHz electron cyclotron resonance proton ion source and a dual-lens low energy beam transport

The structure and preliminary commissioning results of a new 2.45 GHz ECR proton ion source and a dual-lens low energy beam transport (LEBT) system are presented in this paper. The main magnetic field of the ion source is provided by a set of permanent magnets with two small electro-solenoid magnets at the injection and the extraction to fine tune the magnetic field for better microwave coupling. A 50 keV pulsed proton beam extracted by a three-electrode mechanism passes through the LEBT system of length of 1183 mm. This LEBT consists of a diagnosis chamber, two Glaser lenses, two steering magnets, and a final beam defining cone. A set of inner permanent magnetic rings is embedded in each of the two Glaser lenses to produce a flatter axial-field to reduce the lens aberrations.

Deuteron injector for Peking University Neutron Imaging Facility project

The deuteron injector developed for the PKUNIFTY (Peking University Neutron Imaging Facility) has been installed and commissioned at Peking University (PKU). The injector system must transfer 50 keV 50 mA of D(+) ion beam to the entrance of the 2 MeV radio frequency quadrupole (RFQ) with 10% duty factor (1 ms, 100 Hz). A compact 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source and a 1.36 m long low energy beam transport (LEBT) line using two solenoids was developed as the deuteron injector. A φ5 mm four-quadrant diaphragm was used to simulate the entrance of RFQ electrodes. The beam parameters are measured after this core with an emittance measurement unit (EMU) and a bending magnet for ion fraction analysis at the end of injector. During the commissioning, 77 mA of total deuteron beam was extracted from PMECR and 56 mA of pure D(+) beam that passed through the φ5 mm four-quadrant diaphragm was obtained at the position of RFQ entrance with the measured normalized rms emittance 0.12-0.16π mm mrad. Ion species analysis results show that the deuteron fraction is as high as 99.5%. All of the parameters satisfy PKUNIFTY's requirements. In this paper, we will describe the deuteron injector design and report the commissioning results as well as the initial operation.

The deuteron injector progress of the Peking University Neutron Imaging Facility project

A deuteron radio frequency quadrupoles injector h has been developed at Peking University. A permanent magnetic electron cyclotron resonance (ECR) ion source is used in the injector system. A 50 keV 100 mA proton beam has been extracted from the ECR ion source and the measured normalized rms emittance is 0.11-0.14pi mm mrad. A deuteron beam has also been extracted at 50 kV with 83 mA total current and its emittance is less than 0.18pi mm mrad. The proton beam transmission has been investigated on a low energy beam transport test bench, and up to 93% transmission can be reached. The new injector with two solenoids has been designed and is being constructed. All the development results will be presented in this paper.

Preliminary studies on space charge compensation by analyzing residual argon gas ion signals

An experimental method is related to research the space charge compensation (SCC) effect in low energy intense proton beams by analyzing residual gas (RG) ion signals. The signal curves were measured with an energy spectrometer under the RG pressure from 1.2x10(-3) to 1.6x10(-2) Pa. Most of the data showed a similar trend with our theoretical predicts. From the RG ion energy spectra the potential distribution in the beam was calculated both with and without the SCC effect. Moreover, as a preliminary result, a best compensating point is achieved for the low energy beam transport transmission of 40 KeV, 60 mA H(+) beam in Peking University.

Upgrade of the extraction system of permanent magnet electron cyclotron resonance ion source

A set of new ion extraction electrodes have been designed for the permanent magnetic electron cyclotron resonance ion source at Peking University to improve beam quality and transmission. PBGUNS has been used to optimize the extraction electrodes and simulate the beam behavior at the extraction region. The experiments showed that with the new system, the beam half divergence angle can be less than 40 mrad and the normalized rms emittance is about 0.13pi mm mrad when the extracted current is 100 mA at 50 keV in pulse mode. The voltage of the suppression electrode has great effect on beam divergence. The effect of the microwave power and gas flow is also studied.

The influence of magnetic field configuration on an electron cyclotron resonance ion source

In an electron cyclotron resonance (ECR) ion source, the magnetic field along the axis of the plasma chamber and extraction system is a key parameter. At Peking University, a new 2.45 GHz ECR ion source (PMECR III), dedicated to proton production, has been developed to investigate the influence of the magnetic field on the gas discharge and beam characteristics. The magnetic configuration is provided by two permanent magnet rings independently tunable along the source axis. Moreover, the beam extraction position changes by moving the whole magnetic system along the source axis and by using different lengths of plasma electrode. A brief description of the source is reported and the magnetic field influence results are presented.

Experimental results of an electron cyclotron resonance oxygen source and a low energy beam transport system for 1 MeV integral split ring radio frequency quadruple accelerator upgrade project

To meet the requirements of developing separated function radio frequency quadruple (rfq) and upgrading the 1 MeV integral split ring rfq accelerator, an electron cyclotron resonance O(+) ion source and low energy beam transport (LEBT) system have been developed. Using two Einzel lenses to focus the beam, more than 6 mA O(+) peak beam current with energy of 22 keV can be easily obtained at the end of LEBT when the duty faction is at 1/6. The normalized root-mean-square emittance of 90% of the beam is about 0.12pi mm mrad. By changing the focusing power of lenses, the beam waist can be shifted from 80 mm before the beam diaphragm 2 to 80 mm after it. The experimental results will be presented in this article.

Study on proton fraction of beams extracted from electron cyclotron resonance ion source

A permanent magnet electron cyclotron resonance ion source PMECR II is used to generate proton ions for radio frequency quadrupole (RFQ) injection at Peking University (PKU). The proton fractions of the extracted beam were measured at the positions both after extraction system of ion source and the end of low energy beam transport line (LEBT). Experiments show that the proton fraction has a rise time within a beam pulse, and its value varies with pulse width and microwave power. The proton fractions measured at different positions are comparable.

Comparison of the pharmacology of hydroxamate- and carboxylate-based matrix metalloproteinase inhibitors (MMPIs) for the treatment of osteoarthritis

OBJECTIVE AND DESIGN

Hydroxamic-and carboxylic-acid based matrix metalloproteinase inhibitors (MMPIs) were compared for their potency against various MMPs, pharmacodynamic properties and in vivo efficacy in a model of cartilage degeneration.

MATERIALS AND METHODS

The MMPIs were evaluated for their ability to inhibit human MMPs using the quenched fluorescence assay. The ability of the MMPIs to inhibit the degeneration of the knee joint was evaluated in rats injected intraarticularly with iodoacetate. The amount of MMPI in the plasma and cartilage was determined using liquid chromatography/mass spectrometry/mass spectrometry (LC/ MS/MS). Plasma protein binding was measured by ultrafiltration and unbound MMPI was quantitated using HPLC.

RESULTS

The hydroxamic acid based inhibitor PGE-3321996 and the carboxylic acids PGE-2909492 and PGE-6292544 were potent MMP-13 inhibitors, but only the hydroxamic acid PGE 3321996 demonstrated significant inhibition of knee degeneration in the rat iodoacetate model. Both of the carboxylic acids demonstrated superior pharmacokinetic properties and established much higher plasma concentrations than the hydroxamic acid. However, neither of the carboxylic acids was detectable in the cartilage, whereas, the hydroxamic acid was present in both the cartilage and the plasma. The carboxylic acid based MMPIs also demonstrated higher plasma protein binding (>99%) than the hydroxamic acid (79%).

CONCLUSIONS

Carboxylic acid-based MMPIs were identified that had superior in vivo plasma exposure compared to a hydroxamic acid inhibitor but lacked in vivo efficacy in the rat iodoacetate model of cartilage degeneration. The lack of in vivo efficacy of the carboxylic acid based MMPIs were probably due to their lack of cartilage penetration which was related to their physicochemical properties.

Formation of MTBE-DNA adducts in mice measured with accelerator mass spectrometry

Methyl tert-butyl ether (MTBE) is a gasoline oxygenate and antiknock additive substituting for lead alkyls currently in use worldwide. Previous studies have shown that MTBE at very high doses induces tumors in rodents. The aim of the present study was to examine directly the binding ability of MTBE onto DNA, demonstrating its potential genotoxicity. MTBE-DNA adducts and their decay kinetics in mice have been measured by using doubly 14C-labeled MTBE with an advanced, ultrasensitive technique: accelerator mass spectrometry (AMS). It was found that MTBE definitely formed adducts with DNA in mouse lung, liver, and kidney in a log/log linear dose-response relationship. The distribution sequence of DNA adducts in these tissues is: lung > liver > kidney. The level of MTBE-DNA adducts peaked at 12 h postadministration in the lung and peaked at 6 h postadministration in the liver. Then the adducts declined rapidly until 5 days postadministration and thereafter declined much more slowly. To our knowledge, this is the first report on DNA adduction with MTBE in vivo. The mechanism of the formation of MTBE-DNA adducts also is discussed.

Inhibition of nicotine-DNA adduct formation in mice by six dietary constituents

Nicotine [3-(1-methyl-2-pyrrolidinyl)-pyridine] is a major alkaloid in tobacco products and has proven to be a potential genotoxic compound. Many natural dietary products can suppress the DNA adduction, and hence act as inhibitors of cancer. In this study, we investigated the inhibitory effects of curcumin, garlic squeeze, grapeseed extract, tea polyphenols, vitamin C, and vitamin E on nicotine-DNA adduction in vivo using an ultrasensitive method of accelerator mass spectrometry (AMS). The results demonstrated that all the dietary constituents induced marked dose-dependent decrease in nicotine-DNA adducts as compared with the control. The reduction rate reached about 50% for all agents, except garlic squeeze (40%), even at its highest dose level. Amongst the six agents, grapeseed extract exhibited the strongest inhibition to the DNA adduct formation. Therefore, we may arrive at a point that these dietary constituents are beneficial to prevent the harmful adduct formation, and thus to block the potential carcinogenesis induced by nicotine.

Separation and identification methods for metalloproteinase inhibitors

Metalloproteinase inhibitors are being explored for the treatment of a wide variety of human diseases including cancers, arthritis, cardiovascular disorders, human immunodeficiency virus infection, and central nervous system illnesses. This review provides an overview of various analytical sample preparation, separation, detection, and identification techniques employed for the quantitative and qualitative determination of these inhibitor compounds. Special emphasis is placed on biological sample preparation by automated solid-phase extraction, liquid-liquid extraction, and protein precipitation by centrifugation or filtration. Other sample preparation methodologies are also evaluated. Applications of high-performance liquid chromatography. gas chromatography, and capillary electrophoresis to the quantitative determination of metalloproteinase inhibitors are described. Examples of qualitative analysis of metalloproteinase inhibitors by hyphenated liquid chromatography with mass spectrometry and nuclear magnetic resonance are also presented. The advantages and limitations of these separation and identification methodologies as well as other less frequently employed techniques are assessed and discussed.

Ion-exchange liquid chromatographic analysis of bisphosphonates by on-line post-column photochemical reaction and spectrophotometric detection

A simple ion-exchange high-performance liquid chromatographic method was developed and employed for the analysis of bisphosphonate compounds in dosage formulations using on-line post-column photochemical reactions. The method used molybdate as the post-column reagent to react with the photolyzed bisphosphonate to form phosphomolybdate for enhanced spectrophotometric detection. A bisphosphonate compound, 2-thioethane-1,1-bisphophonic acid, was selected to evaluate the separation using both isocratic and gradient elution methods, along with the effects of other experimental parameters including mobile phase composition, flow-rate and post-column reagent concentration. The gradient elution method showed improved resolution and detection sensitivity compared to the isocratic elution method. The optimized gradient method was simple, reproducible, and specific to bisphosphonate compounds. It was successfully employed for the stability study of the bisphosphonate compound in pharmaceutical dosage formulations.

The development of new carboxylic acid-based MMP inhibitors derived from a cyclohexylglycine scaffold

A series of carboxylic acids was prepared based on cyclohexylglycine scaffolds and tested for potency as matrix metalloproteinase (MMP) inhibitors. Detailed SAR for the series is reported for five enzymes within the MMP family, and a number of inhibitors such as compound 18 display low nanomolar potency for MMP-2 and MMP-13, while selectively sparing MMP-1 and MMP-7.

[Synthesis and bioactivity of some 3,4-diacyloxybenzopyrans]

Considerable attention is now being given to the potassium channel openers of benzopyrans as potential therapeutical agents for hypertension. In order to search for novel antihypertensive with high efficacy and low toxicity, integrating structural features of cromakalim and praeruptorin C, twenty-four compounds of 3,4-diacyloxybenzopyrans were designed and synthesized. Some of them exhibited hypotensive activity in Sprague Dawley rats.

Development of new carboxylic acid-based MMP inhibitors derived from functionalized propargylglycines

A series of carboxylic acids were prepared from a propargylglycine scaffold and tested for efficacy as matrix metalloproteinase (MMP) inhibitors. Detailed SAR for the series is reported for four enzymes within the MMP family. The inhibitors were typically potent against collagenase-3 (MMP-13) and gelatinase A (MMP-2), while they spared collagenase-1 (MMP-1) and only moderately inhibited stromelysin (MMP-3). Compound 40 represents a typical inhibition profile of a compound with reasonable potency. Introduction of polar groups was required in order to generate inhibitors with acceptable water solubility, and this often resulted in a loss of potency as in compound 63. High serum protein binding proved to be a difficult hurdle with many compounds such as 48 showing >99% binding. Some compounds such as 64 displayed approximately 90% binding, but no reliable method was discovered for designing molecules with low protein binding. Finally, selected data regarding the pharmacokinetic behavior of these compounds is presented.

Fully automated 96-well liquid-liquid extraction for analysis of biological samples by liquid chromatography with tandem mass spectrometry

A fully automated high-throughput liquid-liquid extraction (LLE) methodology has been developed for preparation of biological samples using a 96-well LLE plate and a 96-channel robotic liquid handling workstation. The 96-well LLE plate is made of a 96-well filter plate filled with inert diatomaceous earth particles, allowing continuous and efficient extraction of analytes between the aqueous biological sample and the organic extraction solvent. Two carboxylic acid-based protease inhibitor compounds with high and low levels of plasma protein binding were chosen for the development and application of the automated methodology. The LLE extracts of the plasma samples of the two compounds were analyzed by high-performance liquid chromatography with electrospray (ESI) tandem mass spectrometry (LC-MS/MS). The LC-MS/MS method was developed using a rapid gradient LC separation, followed by sample introduction through an ionspray interface in the negative ion mode and tandem mass spectrometric detection with selected reaction monitoring. In the optimized LLE method, a formate buffer solution was first loaded into a 96-well filter plate packed with inert diatomaceous earth material. Then crude plasma samples and a water-immiscible organic solvent, methyl ethyl ketone, were sequentially added to the LLE plate so that LLE would occur in the interface between the two liquid phases on the surface of individual particles in each well. The organic eluate containing extracted analytes was evaporated and reconstituted for LC-MS/MS analysis. This fully automated LLE methodology avoids several disjointed steps involved in a manual or semiautomated LLE method, leading to significantly reduced sample preparation time, increased sample throughput, and clean sample extracts for improved ESI-MS/MS detection. The automated LLE methodology is universal and can be employed for sample preparation of other biological fluids. The complete bioanalytical method, based on the automated LLE and fast gradient LC-MS/MS, was validated and successfully applied to the quantitative analysis of protease inhibitors in rat plasma.

Development of new hydroxamate matrix metalloproteinase inhibitors derived from functionalized 4-aminoprolines

A series of hydroxamates was prepared from an aminoproline scaffold and tested for efficacy as matrix metalloproteinase (MMP) inhibitors. Detailed SAR for the series is reported for five enzymes within the MMP family, and a number of inhibitors, such as compound 47, display broad-spectrum activity with sub-nanomolar potency for some enzymes. Modifications of the P1' portion of the molecule played a key role in affecting both potency and selectivity within the MMP family. Longer-chain aliphatic substituents in this region of the molecule tended to increase potency for MMP-3 and decrease potency for MMP-1, as exemplified by compounds 48-50, while aromatic substituents, as in compound 52, generated broad-spectrum inhibition. The data is rationalized based upon X-ray crystal data which is also presented. While the in vitro peroral absorption seemed to be less predictable, it tended to decrease with longer and more hydrophilic substituents. Finally, a rat model of osteoarthritis was used to evaluate the efficacy of these compounds, and a direct link was established between their pharmacokinetics and their in vivo efficacy.

Hyphenated HPLC-NMR and its applications in drug discovery

Hyphenated HPLC-NMR is a fast growing technology, allowing rapid and detailed structural characterization of unknown mixtures. The technical aspects of the technology are reviewed on the basis of system configuration, operation, solvent suppression, HPLC and NMR optimization, and detection. The combined use of HPLC-NMR and HPLC-MS is also described and discussed. Various applications of HPLC-NMR and integrated HPLC-NMR-MS in drug discovery, especially in the separation and structure elucidation of drug impurities, reaction mixtures, degradation products, in vitro and in vivo metabolites, and combinatorial library samples, are illustrated.

Automated 96-well SPE and LC-MS-MS for determination of protease inhibitors in plasma and cartilage tissues

Bioanalytical methods based on automated solid-phase extraction (SPE) and high-performance liquid chromatography with electrospray tandem mass spectrometry (LC-MS-MS) have been developed and utilized for the determination of MMP inhibitors in plasma and cartilage tissues. The SPE methods were automated using a 96-well extraction plate and a 96-channel programmable liquid-handling workstation. The LC-MS-MS methods were developed using a rapid gradient LC separation, followed by sample introduction through an ionspray interface in the positive ion mode and tandem mass spectrometric detection with selected reaction monitoring. In the optimized SPE methods, crude plasma or ground cartilage supernatant samples were loaded onto an SPE plate to remove proteins and other interfering components in the matrixes to render relatively clean extracts for LC-MS-MS analysis. Compared to the simple plasma protein precipitation method, the automated SPE method afforded significant time-saving in sample preparation and improved sensitivity in MS detection. The methods were validated and successfully applied to the analysis of protease inhibitors in plasma and cartilage tissues.

Automated high-throughput liquid-liquid extraction for initial purification of combinatorial libraries

An automated high-throughput liquid-liquid extraction (LLE) methodology has been developed and utilized for the initial purification of the combinatorial library samples containing unreacted amines and other water-soluble byproducts or impurities. Various extraction solvents were evaluated along with different extraction devices. The LLE method was automated using 96-well-format plates and a robotic liquid-handling workstation. In the optimized LLE method, crude combinatorial library samples were dissolved in a water-immiscible organic solvent, butyl acetate, and added to each well in a 96-well-format plate packed with an inert support material coated with hydrochloric acid. Separation occurs based on the partitioning of the compounds between two liquid phases. Product recovery, purity, and amine removal efficiency were determined by HPLC with and without precolumn derivatization. The automated method was successfully applied to the cleanup of some representative combinatorial library samples with greater than 98% amine removal and an average product purity of 90%. The application of the automated high-throughput LLE method should greatly reduce the labor, time, and cost associated with the purification of combinatorial libraries.

Simultaneous determination of enantioselective plasma protein binding of aminohydantoins by ultrafiltration and chiral high-performance liquid chromatography

Chiral HPLC methods were developed and utilized for the simultaneous determination of plasma protein binding of enantiomers of two racemic aminohydantoin compounds. Reversed-phase HPLC with the use of a polysaccharide-type chiral stationary phase column was employed for the separation and quantitation of the enantiomers of the two compounds with detection limits in the range 5-10 ng/ml in the plasma matrix. The chiral HPLC methods were selective, sensitive and reproducible. The R and S enantiomers of both compounds were baseline-resolved under the chromatographic conditions employed. Ultrafiltration techniques were applied to determining the plasma protein binding for each enantiomer in rat, dog and human plasma. The results clearly show stereoselective binding of the two enantiomers of each compound with higher protein binding of the R enantiomer than the S enantiomer in rat, dog and human plasma. Binding association constants were also determined to be in the range 1.01-14.0 x 10(4) M(-1) at 37 degrees C. Both the protein binding percentage and binding association constant were enantioselective and species-dependent. Such information is important for a clear understanding of the differences in biological activity as well as in pharmacokinetic and pharmacodynamic properties between the two enantiomers of each compound in the drug discovery and development process.

Application of LC-NMR and LC-MS to the identification of degradation products of a protease inhibitor in dosage formulations

LC-NMR and LC-MS were applied to the characterization of six degradation products of a protease inhibitor, N-hydroxy-1,3-di-[4-ethoxybenzenesulphonyl]-5,5-dimethyl-[1,3]c yclohexyldiazine-2-carboxamide, in a dosage formulation. A reversed-phase HPLC method was developed for the separation of the parent compound and its six degradation products. LC-MS was then utilized to obtain the molecular weight and fragmentation information using an electrospray ionization (ESI) interface in the positive ion mode. LC-NMR was employed to acquire detailed structural information using a selective solvent suppression pulse sequence in the stop flow mode. This work demonstrated the usefulness of this integrated approach for the rapid and unambiguous identification of drug compounds and their degradation products in dosage formulations.

Gas chromatographic-mass spectrometric analysis of hydroxylamine for monitoring the metabolic hydrolysis of metalloprotease inhibitors in rat and human liver microsomes

A gas chromatographic-mass spectrometric (GC-MS) method was developed for the analysis of hydroxylamine (HA) in supernatants obtained from liver microsomes. HA monitoring was used to determine the metabolic hydrolysis of two hydroxamic acid-based matrix metalloprotease inhibitors in rat and human liver microsomes. The hydrolysis of the hydroxamic acids to their corresponding carboxylic acids releases HA as a common metabolic product. HA was derivatized to acetone oxime by addition of acetone to the liver microsomal supernatant, followed by direct injection of the supernatant into the GC-MS, with detection of the oxime by selected-ion-monitoring. The method is simple, reproducible, and sensitive for the determination of the hydrolysis of hydroxamic acid compounds, where hydrolysis is the major metabolic pathway. The methodology can be used for rank ordering and selecting hydroxamic acid analogs based on their susceptibility to hydrolysis.

Direct determination of stability of protease inhibitors in plasma by HPLC with automated column-switching

Automated column-switching HPLC methods were developed and utilized for the direct analyses of three hydroxamic acid based metalloprotease inhibitors in rat plasma. These column-switching methods involved the use of a restricted-access media (RAM) precolumn and a column-switching valve, allowing the complete automation of sample preparation and HPLC. The plasma samples were directly injected onto a precolumn packed with SPS/ODS stationary phase and then backflushed onto an ODS analytical column using a 6-port column-switching device. The drug stability in rat plasma was determined using both the automated and traditional HPLC methods. The results obtained from the automated column-switching methods were in good agreement with those from traditional methods that involve sequential protein precipitation, liquid extraction, solvent evaporation, and sample reconstitution. In addition to the elimination of labor-intensive and time-consuming sample preparation procedures, the column-switching methods allowed on-line analyte enrichment and accurate determination of drug stability in plasma with detection limits in the range of 10-20 ng/ml(-1). This work represents, for the first time, a drug stability study in plasma by automated column-switching HPLC technique with the use of a RAM column. Our column-switching methods can be readily adapted to any existing HPLC system with minimal hardware modification.

Permeability of articular cartilage to matrix metalloprotease inhibitors

PURPOSE

To develop an in vitro cartilage permeation model for cartilage permeability study and to evaluate the effects of molecular hydrophilicity and cartilage location on the permeability of articular cartilage to matrix metalloprotease inhibitors.

METHODS

An in vitro cartilage permeation model was developed and utilized to determine the permeability of articular cartilage to the matrix metalloprotease inhibitors of different hydrophilicity. Permeability coefficients were obtained by measuring the steady-state flux of the inhibitor compounds. HPLC methods were also developed and employed for the analysis of drug levels in assay media.

RESULTS

The relationship between permeability and hydrophilicity of drug molecules was examined. Results indicated that the permeability coefficient increased with increasing hydrophilicity of the molecule. Additionally, the relationship between the permeability and the location of the cartilage section within the animal joint was investigated. Our results showed that the drug molecules penetrated faster in the surface layer cartilage than in the deep layer cartilage.

CONCLUSIONS

Increasing the hydrophilicity of a molecule would increase its permeability across articular cartilage. The in vitro cartilage permeation model developed could be used to rank order drug compounds according to their cartilage permeability profiles and to aid in drug selection and development.

Direct pharmaceutical analysis of bisphosphonates by capillary electrophoresis

Bisphosphonate compounds have been studied as a class of potential drugs for the treatment of various bone diseases. However, the analyses of these compounds are problematic because most of them do not contain strong chromophores. Based on the unique structures of these compounds, we have employed a capillary electrophoresis (CE) technique for the characterization of these compounds in pharmaceutical dosage formulations. In this study, two CE methods were developed for the determination of a bisphosphonate compound, 2-thioethane-1,1-bisphosphonic acid. The first method involved the use of an uncoated column, a phosphate buffer, and hydrostatic injection with direct UV absorbance detection. The method showed excellent resolution and precision with a reasonable detection limit of 30 microg/ml. Sensitivity was further improved using a glycerol-coated column, together with a phosphate buffer of higher concentration and electrokinetic injection under sample stacking conditions. This modified method revealed a significant improvement in sensitivity with a detection limit of about 50 ng/ml. Both methods demonstrated high simplicity and excellent reproducibility and were successfully applied to the quantitative analyses of pharmaceutical dosing solutions.

[Synthesis and antiarrhythmic activity of some (erythro)-phenylpropanediolamine compounds]

For the purpose of searching for new drug with high potency and simple chemical structure, the dominant conformation and structural parameters of Guan-Fu base (GFA) molecule were modelled and calculated with a SGI-4D 25G computer. The propanediolamine chain in GFA might be considered to be a pharmacophore responsible for the bioactivity and the configuration of the chain seemed important. Thus, thirteen compounds of (erythro)-p-x-PhCHOHCHOHCH2NHR(x = H, I1-7; X = NO2, II1-6) were prepared. Among them, 10 compounds showed antiarrhythmic effect on aconitine-induced arrhythmia in rats. The ED50(to stop VT) of I2 and ED50(to stop VP) of I3 were shown to be comparable with those of GFA. In the synthesis, no stereoselectivity was found in the Prevost reaction with allylamine analogues (a1-7). After a1-7 were acetylated, the erythro type products(I1-7) were obtained.

[Delayed suprachoroidal hemorrhage after glaucoma filtering surgery]

888 glaucomatous eyes were done filtering surgery, and delayed suprachoroidal hemorrhage occurred in 13 eyes (1.46%). High pre-operative intraocular pressure and glaucoma associated with ocular vessel anomalies were the most risky factors of this complication.

[Traumatic lens dislocation-related glaucoma]

Among 106 patients of traumatic lens dislocation, comprising 70 males and 36 females aged 3-90 years, secondary glaucoma occurred in 93 cases (87.7%). The authors are of the opinion that lenses dislocated into the anterior chamber should be removed as soon as possible, and dislocated lens in the vitreous cavity without adhesion to the retina should also be extracted with vitrectomy. For patients with pupil block glaucoma that indicate peripheral iridectomy, the locations of operation should be carefully selected.

Cardiovascular effects of substituted tetrahydroisoquinolines in rats

1. A series of substituted tetrahydroisoquinolins derived from the cleavage products of tetrandrine were found to inhibit [3H]-nitrendipine binding to rat cerebral cortical membranes. Those compounds which displaced [3H]-nitrendipine binding were also able to inhibit high KCl-induced contraction of rat aorta in vitro. 2. There was a significant correlation between the ability of these tetrahydroisoquinolines to inhibit [3H]-nitrendipine binding and KCl-induced contraction (r = 0.99, P less than 0.001). 3. CPU-23 (1-(1-[(6-methoxy)-naphth-2-yl])-propyl-2-(1-piperidine)-acetyl- 6,7- dimethoxy-1,2,3,4-tetrahydroisoquinoline), one of the most potent compounds identified in this series, behaved as a simple competitive inhibitor at the [3H]-nitrendipine binding site and reduced the apparent affinity but not the maximal number of binding sites in saturation analysis. 4. In contrast to nifedipine which caused hypotension and tachycardia, CPU-23 induced both hypotension and bradycardia in a dose-dependent manner in pentobarbitone-anaesthetized Sprague-Dawley rats, spontaneously hypertensive and age-matched normotensive WKY rats. 5. It is suggested that CPU-23 may exert its cardiovascular effects via interaction with the dihydropyridine binding site on the L-type calcium channel.

[The anterior chamber depth after trabeculectomy]

The anterior chamber depth was measured with the Haag-Streit Pachymeter in 26 cases (33 eyes) of primary angle-closure glaucoma preoperatively and postoperatively on days 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 30, 45 and 60. After successful trabeculectomy, the anterior chamber depth became shallower, particularly on days 2 to 4 postoperative, and then gradually deepened after day 5. By day 14 after surgery, the anterior chamber depth was recovered up to 91% of the preoperative level, and by day 30 up to 93%, to remain essentially stable thereafter.

Anti-arrhythmic activities of six indole derivatives of changrolin

The indole-derived compounds, which possessed side chains resembling those of changrolin (4-[3',5'-bis[(N-pyrrolidinyl)methyl]-4'-hydroxyaniline]-quinazoline) showed potent anti-arrhythmic activity by restoration of sinus rhythm from ouabain-induced tachycardia in guinea pigs. The potency was assessed by comparison of the maintenance time of sinus rhythm recovered from tachyarrhythmias induced by ouabain. The promising compound was MI2 with piperidyl residue on position 3 & 5 of phenol moiety. There was no difference in anti-arrhythmic activities resulting from substitutions between a benzene ring and methyl residue at position 2 of indole, but the latter had weaker parasympatholytic activity. The anti-arrhythmic activity of MI2 (greater than 60 min) was 2.4 times more potent then changrolin (25 min), but its anti-cholinergic activity was only half of the latter. To compare the suppressive effect on reperfusion-induced arrhythmias by iv MI2 at different time in relation to the ligation-reperfusion protocol, it was the most effective when administered either 30 min prior to coronary occlusion or at the moment of reperfusion. The compound MI might belong to the Ic group shown by the slowing impulse conduction within the heart.

Benzylisoquinoline compounds inhibit the ability of calmodulin to activate cyclic nucleotide phosphodiesterase

Benzylisoquinoline compounds antagonised the ability of calmodulin (CaM) to stimulate the activity of calmodulin-dependent cyclic nucleotide phosphodiesterase (CaM-PDE). This 'anti-CaM' activity was related to the hydrophobicity of the non-polar terminal region of the antagonist molecule. Antagonistic potency increased with the increase of hydrophobicity; the anti-CaM activity did not change when the polar terminus was a tertiary amine or quarternary amine. The anti-CaM potency was greater for bisbenzylisoquinoline compounds than for monobenzylisoquinoline compounds. Among the bisbenzylisoquinoline compounds anti-CaM pathway was: D3 greater than D2 berbamine greater than daurisoline greater than dauricine. Compound D3, which exhibited an IC50 value of 2.8 microM, was one of the most potent calmodulin antagonists, among benzylisoquinoline compounds, so far reported.