Effects of appropriate low-temperature treatment on the yield and quality of pigmented potato (Solanum tuberosum L.) tubers.

Temperature is one of the important environmental factors affecting plant growth, yield and quality. Moreover, appropriately low temperature is also beneficial for tuber coloration. The red potato variety Jianchuanhong, whose tuber color is susceptible to temperature, and the purple potato variety Huaxinyangyu, whose tuber color is stable, were used as experimental materials and subjected to 20 °C (control check), 15 °C and 10 °C treatments during the whole growth period. The effects of temperature treatment on the phenotype, the expression levels of structural genes related to anthocyanins and the correlations of each indicator were analyzed. The results showed that treatment at 10 °C significantly inhibited the potato plant height, and the chlorophyll content and photosynthetic parameters in the leaves were reduced, and the enzyme activities of SOD and POD were significantly increased, all indicating that the leaves were damaged. Treatment at 10 °C also affected the tuberization of Huaxinyangyu and reduced the tuberization and coloring of Jianchuanhong, while treatment at 15 °C significantly increased the stem diameter, root-to-shoot ratio, yield and content of secondary metabolites, especially anthocyanins. Similarly, the expression of structural genes were enhanced in two pigmented potatoes under low-temperature treatment conditions. In short, proper low temperature can not only increase yield but also enhance secondary metabolites production. Previous studies have not focused on the effects of appropriate low-temperature treatment during the whole growth period of potato on the changes in metabolites during tuber growth and development, these results can provide a theoretical basis and technical guidance for the selection of pigmented potatoes with better nutritional quality planting environment and the formulation of cultivation measures.

Screening and functional analysis of StMYB transcription factors in pigmented potato under low-temperature treatment.

MYB transcription factors play an extremely important regulatory role in plant responses to stress and anthocyanin synthesis. Cloning of potato StMYB-related genes can provide a theoretical basis for the genetic improvement of pigmented potatoes. In this study, two MYB transcription factors, StMYB113 and StMYB308, possibly related to anthocyanin synthesis, were screened under low-temperature conditions based on the low-temperature-responsive potato StMYB genes family analysis obtained by transcriptome sequencing. By analyzed the protein properties and promoters of StMYB113 and StMYB308 and their relative expression levels at different low-temperature treatment periods, it is speculated that StMYB113 and StMYB308 can be expressed in response to low temperature and can promote anthocyanin synthesis. The overexpression vectors of StMYB113 and StMYB308 were constructed for transient transformation tobacco. Color changes were observed, and the expression levels of the structural genes of tobacco anthocyanin synthesis were determined. The results showed that StMYB113 lacking the complete MYB domain could not promote the accumulation of tobacco anthocyanins, while StMYB308 could significantly promote the accumulation involved in tobacco anthocyanins. This study provides a theoretical reference for further study of the mechanism of StMYB113 and StMYB308 transcription factors in potato anthocyanin synthesis.

Photon blockade with a trapped Λ-type three-level atom in asymmetrical cavity.

We propose a scheme to manipulate strong and nonreciprocal photon blockades in asymmetrical Fabry-Perot cavity with a Λ-type three-level atom. Utilizing the mechanisms of both conventional and unconventional blockade, the strong photon blockade is achieved by the anharmonic eigenenergy spectrum brought by Λ-type atom and the destructive quantum interference effect induced by a microwave field. By optimizing the system parameters, the manipulation of strong photon blockade over a wide range of cavity detuning can be realized. Using spatial symmetry breaking introduced by the asymmetry of cavity, the direction-dependent nonreciprocal photon blockade can be achieved, and the nonreciprocity can reach the maximum at optimal cavity detuning. In particular, manipulating the occurring position of nonreciprocal photon blockade can be implemented by simply adjusting the cavity detuning. Our scheme provides feasible access for generating high-quality nonreciprocal single-photon sources.

Plasma exosomal hsa_circ_0079439 as a novel biomarker for early detection of gastric cancer.

BACKGROUND: Due to the poor prognosis of gastric cancer (GC), early detection methods are urgently needed. Plasma exosomal circular RNAs (circRNAs) have been suggested as novel biomarkers for GC. AIM: To identify a novel biomarker for early detection of GC. METHODS: Healthy donors (HDs) and GC patients diagnosed by pathology were recruited. Nine GC patients and three HDs were selected for exosomal whole-transcriptome RNA sequencing. The expression profiles of circRNAs were analyzed by bioinformatics methods and validated by droplet digital polymerase chain reaction. The expression levels and area under receiver operating characteristic curve values of plasma exosomal circRNAs and standard serum biomarkers were used to compare their diagnostic efficiency. RESULTS: There were 303 participants, including 240 GC patients and 63 HDs, involved in the study. The expression levels of exosomal hsa_circ_0079439 were significantly higher in GC patients than in HDs (P < 0.0001). However, the levels of standard serum biomarkers were similar between the two groups. The area under the curve value of exosomal hsa_circ_0079439 was higher than those of standard biomarkers, including carcinoembryonic antigen, carbohydrate antigen (CA)19-9, CA72-4, alpha-fetoprotein, and CA125 (0.8595 vs 0.5862, 0.5660, 0.5360, 0.5082, and 0.5018, respectively). The expression levels of exosomal hsa_circ_0079439 were significantly decreased after treatment (P < 0.05). Moreover, the expression levels of exosomal hsa_circ_0079439 were obviously higher in early GC (EGC) patients than in HDs (P < 0.0001). CONCLUSION: Our results suggest that plasma exosomal hsa_circ_0079439 is upregulated in GC patients. Moreover, the levels of exosomal hsa_circ_0079439 could distinguish EGC and advanced GC patients from HDs. Therefore, plasma exosomal hsa_circ_0079439 might be a potential biomarker for the diagnosis of GC during both the early and late stages.

OCT6 inhibits differentiation of porcine-induced pluripotent stem cells through MAPK and PI3K signaling regulation.

As a transcription factor of the Pit-Oct-Unc (POU) domain family, octamer-binding transcription factor 6 ( OCT6) participates in various aspects of stem cell development and differentiation. At present, however, its role in porcine-induced pluripotent stem cells (piPSCs) remains unclear. Here, we explored the function of OCT6 in piPSCs. We found that piPSCs overexpressing OCT6 maintained colony morphology and pluripotency under differentiation conditions, with a similar gene expression pattern to that of non-differentiated piPSCs. Functional analysis revealed that OCT6 attenuated the adverse effects of extracellular signal-regulated kinase (ERK) signaling pathway inhibition on piPSC pluripotency by activating phosphatidylinositol 3-kinase-protein kinase B (PI3K-AKT) signaling activity. Our research sheds new light on the mechanism by which OCT6 promotes PSC maintenance.

Pharmacokinetics and Safety of Single-Dose Amphotericin B Colloidal Dispersion in Healthy Chinese Subjects and Population Pharmacokinetic/Pharmacodynamic Analysis to Inform Clinical Efficacy in Invasive Infections Caused by Candida albicans.

PURPOSE: Amphotericin B colloidal dispersion (ABCD) is a less toxic formulation of amphotericin B for the treatment of invasive fungal infections. The pharmacokinetic (PK) profile and safety of a generic ABCD were investigated after a single dose (0.5 to 1.5 mg/kg) administered as an intravenous infusion in 30 healthy Chinese subjects. METHODS: PK data from healthy Chinese male subjects were applied for developing a population PK model to predict the PK profiles of standard doses (3 or 4 mg/kg) in patients. A 5000-time Monte Carlo simulation of AUC0-24/MIC target was implemented to determine the probability of target attainment (PTA) and cumulative fraction of response (CFR) under standard doses. FINDINGS: The PK profiles of intravenous administration of ABCD were best described by a 3-compartmental model with a time-varying clearance and a dose-dependent volume of distribution in the peripheral compartment. PK/pharmacodynamic (PK/PD) analysis revealed that 3 or 4 mg/kg ABCD once a day resulted in favorable CRF (>98%) with 2-log reduction of Candida albicans. A high PTA (>90%) was achieved at MIC ≤2 mg/L for the dosing regimen of ABCD 3 mg/kg and 4 mg/kg for MIC ≤4 mg/L. IMPLICATIONS: PK/PD analysis indicated that a favorable efficacy of ABCD could be reached at a dose of 3 or 4 mg/kg once daily for 14 to 28 days to treat invasive fungal infections caused by C albicans. ClinicalTrials.gov identifier: NCT03577509.

Curcumin protects BEAS­2B cells from PM2.5­induced oxidative stress and inflammation by activating NRF2/antioxidant response element pathways.

Fine particulate matter (PM2.5) with an average aerodynamic diameter of <2.5 µm can cause severe lung injury. Oxidative stress and inflammation are considered the main outcomes of PM2.5 exposure. Curcumin is a well­known antioxidant; however, its effect on PM2.5­induced oxidative injury in airway epithelial cells remains unclear. In the present study, it was demonstrated that pre­treatment with curcumin significantly reduced the PM2.5­induced apoptosis of BEAS­2B human bronchial epithelial cells by decreasing the level of intercellular reactive oxygen species. Western blot analysis revealed that curcumin increased the expression of nuclear factor erythroid 2­related factor 2 (NRF2) and regulated the transcription of downstream genes, particularly those encoding antioxidant enzymes. Moreover, curcumin reduced the PM2.5­induced expression and production of inflammatory factors, and induced the expression of the anti­inflammatory factors, interleukin (IL)­5 and IL­13. Taken together, the present study demonstrates that curcumin protects BEAS­2B cells against PM2.5­induced oxidative damage and inflammation, and prevents cell apoptosis by increasing the activation of NRF2­related pathways. It is thus suggested that curcumin may be a potential compound for use in the prevention of PM2.5­induced tissue injury.

Effects of Different Component Contents of Colistin Methanesulfonate on the Pharmacokinetics of Prodrug and Formed Colistin in Human.

PURPOSES: To evaluate the effects of component contents in different colistin methanesulfonate (CMS) formulas on their clinical pharmacokinetics of the prodrug CMS and the formed colistin. METHODS: Two CMS formulas (CTTQ and Parkedale) were investigated in a single dose, randomized, open-label, crossover study conducted in 18 healthy Chinese subjects. Both CMS formulas met the requirements of European Pharmacopoeia 9.2 with 12.1% difference in the two major active components (CMS A and CMS B). The PK parameters after a single intravenous infusion of CMS at 2.5 mg/kg were calculated and the steady-state plasma colistin concentrations (Css,avg) following multiple dosing, once every 12 h for 7 days, were simulated with the non-compartment model. RESULTS: The systemic exposure (AUC0-inf) of CMS were 59.49 ± 5.90 h·µg/mL and 51.09 ± 4.70 h·µg/mL, and the AUC0-inf of colistin were 15.39 ± 2.63 h·µg/mL and 12.36 ± 2.10 h·µg/mL for CTTQ and Parkedale, respectively. The ratios (90% CI) of geometric mean of AUC0-inf of CTTQ to Parkedale were 116.38% (112.95%, 119.91%) and 124.49% (120.76%, 128.35%) for CMS and colistin, respectively. The predicted Css,avg (95% CI) were 0.92 (0.85, 0.99) µg/mL and 0.74 (0.69, 0.79) µg/mL for CTTQ and Parkedale, respectively. CONCLUSION: The difference in component content in the two CMS formulas had a significant (P < 0.001) impact on the systemic exposure of colistin in human, thus, warranted essential considerations in clinical applications.

Pharmacokinetics of colistin methanesulfonate (CMS) in healthy Chinese subjects after single and multiple intravenous doses.

The high prevalence of extensively drug-resistant Gram-negative pathogens has forced clinicians to use colistin as a last-line therapy. Knowledge on the pharmacokinetics of colistin methanesulfonate (CMS), an inactive prodrug, and colistin has increased substantially; however, the pharmacokinetics in the Chinese population is still unknown due to lack of a CMS product in China. This study aimed to evaluate the pharmacokinetics of a new CMS product developed in China in order to optimise dosing regimens. A total of 24 healthy subjects (12 female, 12 male) were enrolled in single- and multiple-dose pharmacokinetic (PK) studies. Concentrations of CMS and formed colistin in plasma and urine were measured, and PK analysis was conducted using a non-compartmental approach. Following a single CMS dose [2.36 mg colistin base activity (CBA) per kg, 1 h infusion], peak concentrations (Cmax) of CMS and formed colistin were 18.0 mg/L and 0.661 mg/L, respectively. The estimated half-life (t1/2) of CMS and colistin were 1.38 h and 4.49 h, respectively. Approximately 62.5% of the CMS dose was excreted via urine within 24 h after dosing, whilst only 1.28% was present in the form of colistin. Following multiple CMS doses, colistin reached steady-state within 24 h; there was no accumulation of CMS, but colistin accumulated slightly (RAUC = 1.33). This study provides the first PK data in the Chinese population and is essential for designing CMS dosing regimens for use in Chinese hospitals. The urinary PK data strongly support the use of intravenous CMS for serious urinary tract infections.

Development and validation of a UHPLC-MS/MS assay for colistin methanesulphonate (CMS) and colistin in human plasma and urine using weak-cation exchange solid-phase extraction.

A rapid ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay method was developed for determination of CMS and formed colistin in human plasma and urine. After extraction on a 96-well SPE Supra-Clean Weak Cation Exchange (WCX) plate, the eluents were mixed and injected into the UHPLC-MS/MS system directly. A Phonomenex Kinetex XB-C18 analytical column was employed with a mobile phase consisting of solution "A" (acetonitrile:methanol, 1:1, v/v) and solution "B" (0.1% formic acid in water, v/v). The flow rate was 0.4 mL/min with gradient elution over 3.5 min. Ions were detected in ESI positive ion mode and the precursor-product ion pairs were m/z 390.7/101.3 for colistin A, m/z 386.0/101.2 for colistin B, and m/z 402.3/101.2 for polymyxin B1 (IS), respectively. The lower limit of quantification (LLOQ) was 0.0130 and 0.0251 mg/L for colistin A and colistin B in both plasma and urine with accuracy (relative error, %) <± 12.6% and precision (relative standard deviation, %) <± 10.8%. Stability of CMS was demonstrated in biological samples before and during sample treatment, and in the extract. This new analytical method provides high-throughput treatment and optimized quantification of CMS and colistin, which offers a highly efficient tool for the analysis of a large number of clinical samples as well as routine therapeutic drug monitoring.

In vitro simulation of in vivo pharmacokinetic model with intravenous administration via flow rate modulation.

The aim of this paper was to propose a method of flow rate modulation for simulation of in vivo pharmacokinetic (PK) model with intravenous injection based on a basic in vitro PK model. According to the rule of same relative change rate of concentration per unit time in vivo and in vitro, the equations for flow rate modulation were derived using equation method. Four examples from literature were given to show the application of flow rate modulation in the simulation of PK model of antimicrobial agents in vitro. Then an experiment was performed to confirm the feasibility of flow rate modulation method using levo-ornidazole as an example. The accuracy and precision of PK simulations were evaluated using average relative deviation (ARD), mean error and root mean squared error. In vitro model with constant flow rate could mimic one-compartment model, while the in vitro model with decreasing flow rate could simulate the linear mammillary model with multiple compartments. Zero-order model could be simulated using the in vitro model with elevating flow rate. In vitro PK model with gradually decreasing flow rate reproduced the two-compartment kinetics of levo-ornidazole quite well. The ARD was 0.925 % between in vitro PK parameters and in vivo values. Results suggest that various types of PK model could be simulated using flow rate modulation method without modifying the structure. The method provides uniform settings for the simulation of linear mammillary model and zero-order model based on in vitro one-compartment model, and brings convenience to the pharmacodynamic study.

Pharmacokinetics and pharmacodynamics of multiple-dose intravenous nemonoxacin in healthy Chinese volunteers.

This study evaluated the safety and pharmacokinetic/pharmacodynamic profiles of nemonoxacin in healthy Chinese volunteers following multiple-dose intravenous infusion once daily for 10 consecutive days. The study was composed of two stages. In the open-label stage, 500 mg or 750 mg of nemonoxacin (n = 12 each) was administered at an infusion rate of 5.56 mg/min. In the second stage, with a randomized double-blind placebo-controlled design, 500, 650, or 750 mg of nemonoxacin (n = 16 in each cohort; 12 subjects received the drug and the other 4 subjects received the placebo) was given at an infusion rate of 4.17 mg/min. The results showed that, in the first stage, the maximal nemonoxacin concentrations (mean ± SD) at steady state (Cmax_ss) were 9.60 ± 1.84 and 11.04 ± 2.18 µg/ml in the 500-mg and 750-mg cohorts, respectively; the areas under the concentration-time curve at steady state (AUC0-24_ss) were 44.03 ± 8.62 and 65.82 ± 10.78 µg · h/ml in the 500-mg and 750-mg cohorts, respectively. In the second stage, the nemonoxacin Cmax_ss values were 7.13 ± 1.47, 8.17 ± 1.76, and 9.96 ± 2.23 µg/ml in the 500-mg, 650-mg, and 750-mg cohorts, respectively; the AUC0-24_ss values were 40.46 ± 9.52, 54.17 ± 12.10, and 71.34 ± 17.79 µg · h/ml in the 500-mg, 650-mg, and 750-mg cohorts, respectively. No accumulation was found after the 10-day infusion with any regimen. The drug was well tolerated. A Monte Carlo simulation indicated that the cumulative fraction of response of any dosing regimen was nearly 100% against Streptococcus pneumoniae. The probability of target attainment of nemonoxacin therapy was >98% when the MIC of nemonoxacin against S. pneumoniae was ≤1 mg/liter. It is suggested that all of the studied intravenous nemonoxacin dosing regimens should have favorable clinical and microbiological efficacies in future clinical studies. (This study has been registered at ClinicalTrials.gov under registration no. NCT01944774.).

Safety, tolerability, and pharmacokinetics of intravenous nemonoxacin in healthy chinese volunteers.

Nemonoxacin (TG-873870) is a novel nonfluorinated quinolone with potent broad-spectrum activity against Gram-positive, Gram-negative, and atypical pathogens, including vancomycin-nonsusceptible methicillin-resistant Staphylococcus aureus (MRSA), quinolone-resistant MRSA, quinolone-resistant Streptococcus pneumoniae, penicillin-resistant S. pneumoniae, and erythromycin-resistant S. pneumoniae. This first-in-human study was aimed at assessing the safety, tolerability, and pharmacokinetic properties of intravenous nemonoxacin in healthy Chinese volunteers. The study comprised a randomized, double-blind, placebo-controlled, dose escalating safety and tolerability study in 92 subjects and a randomized, single-dose, open-label, 3-period Latin-square crossover pharmacokinetic study in 12 subjects. The study revealed that nemonoxacin infusion was well tolerated up to the maximum dose of 1,250 mg, and the acceptable infusion rates ranged from 0.42 to 5.56 mg/min. Drug-related adverse events (AEs) were mild, transient, and confined to local irritation at the injection site. The pharmacokinetic study revealed that after the administration of 250, 500, and 750 mg of intravenous nemonoxacin, the maximum plasma drug concentration (Cmax) values were 4.826 µg/ml, 7.152 µg/ml, and 11.029 µg/ml, respectively. The corresponding values for the area under the concentration-time curve from 0 to 72 hours (AUC0-72 h) were 17.05 µg · h/ml, 39.30 µg · h/ml, and 61.98 µg · h/ml. The mean elimination half-life (t1/2) was 11 h, and the mean cumulative drug excretion rate within 72 h ranged from 64.93% to 77.17%. Volunteers treated with 250 to 750 mg nemonoxacin exhibited a linear dose-response relationship between the AUC0-72 h and AUC0-∞. These findings provide further support for the safety, tolerability, and pharmacokinetic properties of intravenous nemonoxacin. (This study has been registered at ClinicalTrials.gov under registration no. NCT01944774.).

LC-MS/MS determination of colistin in Mueller-Hinton broth for in vitro pharmacodynamic studies.

A rapid and simple method was developed and validated for the determination of colistin A and B in Mueller-Hinton broth using LC-tandem MS. Both analyte and internal standard (IS) (polymyxin B1) were determined using ESI. The MS data were obtained via the selected reaction monitoring in positive-ion mode. A linear regression (weighted 1/concentration) was used to fit calibration curves over the concentration range of 0.0241-2.41 µg ml(-1) for colistin A and 0.0439-4.39 µg ml(-1) for colistin B. No interference peaks were found in the blank Mueller-Hinton broth tested. Inter- and intraday precision and accuracy were within 85-115% (coefficient of variation). Colistin was stable in the autosampler for at least 24 h at 4 °C and in Mueller-Hinton broth for at least 120 h at 35 °C. This assay has been successfully used to determine colistin A and B in Mueller-Hinton broth for in vitro pharmacodynamic model studies. Accurate determination of colistin in bacterial growth medium has a vital role in the studies examining dosage regimen of and bacterial resistance to colistin.

Genotoxicity and reduced heat shock protein 70 in human airway smooth muscle cells exposed to cigarette smoke extract.

Cigarette smoke is associated with the development of several diseases, such as chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate genotoxicity and heat shock protein 70 (Hsp70) in human airway smooth muscle cells (HASMCs) exposed to cigarette smoke extract (CSE). HASMCs was exposed to CSE with different doses for 24 h. The level of 8-hydroxydeoxyguanosine (8-OHdG) was determined by using HPLC-ECD, the DNA damage was analyzed by using comet assay, and apoptosis was examined by using Annexin-FITC/PI staining. The production of Hsp70 after CSE stimulation was tested. Results indicated that CSE significantly increased the level of 8-OHdG, DNA damage and cell apoptosis, and reduced the production of Hsp70. In particular, levels of Hsp70 were inversely correlated with 8-OHdG, DNA damage and cell apoptosis. It was concluded that cigarette smoke induced genotoxicity and decreased the production of cell protective protein Hsp70, which may contribute to the development of some airway diseases.

Pharmacokinetics and pharmacodynamics of nemonoxacin against Streptococcus pneumoniae in an in vitro infection model.

The aim of this paper was to investigate the pharmacokinetics (PK) and pharmacodynamics (PD) of nemonoxacin, a novel nonfluorinated quinolone, against Streptococcus pneumoniae in vitro. A modified infection model was used to simulate the pharmacokinetics of nemonoxacin following scaling of single oral doses and multiple oral dosing. Four S. pneumoniae strains with different penicillin sensitivities were selected, and the drug efficacy was quantified by the change in log colony counts within 24 h. A sigmoid maximum-effect (Emax) model was used to analyze the relationship between PK/PD parameters and drug effect. Analysis indicated that the killing pattern of nemonoxacin shows a dualism which is mainly concentration dependent when the MIC is low and that the better PK/PD index should be the area under the concentration-time curve for the free, unbound fraction of the drug divided by the MIC (fAUC0-24/MIC), which means that giving the total daily amount of drug as one dose is appropriate under those conditions. When the MIC is high, the time (T) dependency is important and the valid PK/PD index should be the cumulative percentage of a 24-h period in which the drug concentration exceeds the MIC under steady-state pharmacokinetic conditions (f%T>MIC), which means that to split the maximum daily dose into several separate doses will benefit the eradication of the bacteria. To obtain a 3-log10-unit decrease, the target values of fAUC0-24/MIC and f%T>MIC are 47.05 and 53.4%, respectively.

[Analysis of allelic drop-out at short tandem repeat loci].

OBJECTIVE: To explore the cause for allelic drop-out at short tandem repeat (STR) loci upon paternity testing with a PowerPlex® 16 kit. METHODS: A total of 10 642 DNA confirmed paternity testing cases (18 314 parent/child allelic transfers) were analyzed with the PowerPlex® 16 kit. Samples suspected for having allelic drop-out were verified with an Identifiler™ kit and/or locus-specific singleplex amplification systems. PCR products of null alleles were separated and directly sequenced. RESULTS: Eight cases of allelic drop-out were found. The overall rate of null allele in the PowerPlex® 16 system was 0.437 × 10(-3). DNA sequencing has confirmed single base variations within the binding region of published primers, in which 4 cases involved the D18S51 locus (2 cases with G>A transitions at 79 bp upstream of the repeats, 1 case with G>T transversion at 162 bp downstream of the repeats and 1 case with G>C transversion at 74 bp upstream of the repeats), 2 cases involved the D21S11 locus (1 case with C>A transversion at 17 bp upstream of the repeats and 1 case with A>G transition at 12 bp upstream of the repeats). One case involved the FGA locus (1 case with G>A transition at 142 bp downstream of the repeats) and 1 case involved TPOX locus (1 case with G>A transition at 198 bp downstream of the repeats). CONCLUSION: Base variation in the primer binding region may cause failed PCR and result in null allele reports. Alternative primer sets should be used to verify the suspected allelic drop-out. Attention should be paid to this during paternity testing and data exchange for personal identification.

[Repeated morphine pretreatment reduces glutamatergic synaptic potentiation in the nucleus accumbens induced by acute morphine exposure].

Repeated exposure to morphine leads to the addiction, which influences its clinical application seriously. The glutamatergic projection from prefrontal cortex (PFC) to the nucleus accumbens (NAc) plays an important role in rewarding effects. It is still unknown whether morphine exposure changes PFC-NAc synaptic transmission. To address this question, in vivo field excitatory postsynaptic potentials (fEPSPs) induced by electric stimulating PFC-NAc projection fibers were recorded to evaluate the effect of acute morphine exposure (10 mg/kg, s.c.) on glutamatergic synaptic transmission in NAc shell of repeated saline/morphine pretreated rats. It was showed that acute morphine exposure enhanced fEPSP amplitude and reduced paired-pulse ratio (PPR) in saline pretreated rats, which could be reversed by following naloxone injection (1 mg/kg, i.p.), an opiate receptor antagonist. However, repeated morphine pretreatment significantly inhibited both the enhancement of fEPSP amplitude and reduction of PPR induced by acute morphine exposure. Those results indicate that the initial morphine exposure enhances PFC-NAc synaptic transmission by pre-synaptic mechanisms, whereas morphine pretreatment occludes this effect.

Establishment of norvancomycin fluorescence polarization immunoassay for therapeutic drug monitoring.

To establish a rapid and simple fluorescence polarization immunoassay method for determination of norvancomycin serum concentration, we collected 300 serum samples from the patients receiving norvancomycin in the hospitals localized in Shanghai, China. The drug concentrations were measured by the established HPLC method and FPIA with vancomycin kit. A FPIA algorithm for the determination of norvancomycin concentration was established according to the correlation between the FPIA and HPLC results. The methods and algorithm were validated in another 70 clinical samples. HPLC determination showed a good linear correlation within the range of 0.5-100 mg l(-1) of norvancomycin concentrations. The method was validated via extraction recovery, intra- and inter-day methodological recovery and stability of norvancomycin in serum. Correlation analysis between the measurements of HPLC and FPIA in 300 serum samples gave the linear regression equation: (concentration by HPLC)=0.760 × (concentration by FPIA)-0.577 (P<0.001, R(2)=0.982). An algorithm was derived from this correlation for measuring the serum norvancomycin concentrations with FPIA. When it was validated in additional 70 serum samples from patients, 'FPIA algorithm' showed good accuracy versus HPLC: 'FPIA algorithm'=0.93 (HPLC)+0.63, R(2)=0.962, and 94.3% of the results from FPIA algorithm fell within the range of -20%/+20% of HPLC. This algorithm developed in this study can be easily used for determination of norvancomycin using TDx analyzer with vancomycin kit indirectly. It may also be useful for norvancomycin therapeutic drug monitoring.