[Survey of Helicobacter pylori levofloxacin and clarithromycin resistance rates and drug resistance genes in Ningxia, 2020-2022].

Objective: To explore the rate of Helicobacter pylori (Hp) resistance to levofloxacin and clarithromycin and the common mutation patterns of resistance genes in Ningxia, and to assess the concordance between phenotypic resistance and genotypic resistance. Methods: Cross-sectional study. Patients diagnosed with Hp infection in 14 hospitals in Ningxia region from February 2020 to May 2022 were retrospectively selected. Hp strains were isolated from gastric biopsy specimens of Hp-infected patients and subjected to phenotypic drug sensitivity testing and detection of resistance genes to analyze the rate of Hp resistance to levofloxacin and clarithromycin and the common mutation patterns of resistance genes in Ningxia region; and the concordance rate and Kappa concordance test were used to assess the concordance between phenotypic resistance and genotypic resistance. Results: A total of 1 942 Hp strains were isolated and cultured, and among the infections, 1 069 cases (55.0%) were male and 873 cases (45.0%) were female, aged (50.0±12.5) years (15-86 years). The rates of Hp resistance to levofloxacin and clarithromycin in Ningxia were 42.1% (818/1 942) and 40.1% (779/1 942), respectively, and the rate of dual resistance to both was 22.8% (443/1 942). The rate of resistance to levofloxacin and clarithromycin of Hp strains from female patients was higher than in male patients (levofloxacin: 50.4%(440/873) vs 35.4%(378/1 069); clarithromycin: 44.4%(388/873) vs 36.6%(391/1 069), both P<0.001). Among the GyrA gene mutations associated with levofloxacin resistance, the differences in mutation rate of amino acid at positions 87 and 91 were statistically significant in both drug-resistant and sensitive strains(both P<0.001), except for Asn87Thr. Hp strains were statistically significant for levofloxacin (Kappa=0.834, P<0.001) and clarithromycin (Kappa=0.829, P<0.001) had good concordance in resistance at the phenotypic and genotypic levels. Conclusion: The resistance of Hp to levofloxacin and clarithromycin in Ningxia region is severe, and there is good consistency between genotypic and phenotypic resistance.

Lentivirus-mediated platelet-derived factor VIII gene therapy in murine haemophilia A.

BACKGROUND: Previous studies from our laboratory have demonstrated that lineage-targeted synthesis of factor VIII (FVIII) under the direction of the platelet-specific integrin alphaIIb gene promoter (2bF8) can correct the murine haemophilia A phenotype even in the presence of high titer inhibitory antibodies in a transgenic mouse model. OBJECTIVE: In this study, we assessed the efficacy of using a genetic therapy approach to correct haemophilia A in FVIII-deficient (FVIII(null)) mice by transplantation of bone marrow (BM) transduced with a lentivirus (LV)-based gene transfer cassette encoding 2bF8. RESULTS: Functional FVIII activity (FVIII:C) was detected in platelet lysates from treated mice and the levels were similar to 2bF8 heterozygous transgenic mice. Mice transplanted with 2bF8 LV-transduced BM survived tail clipping and we did not detected inhibitory or non-inhibitory FVIII antibodies over the period of this study (11 months). Furthermore, BM transferred from the primary transplant recipients into FVIII(null) secondary recipients demonstrated sustained platelet-FVIII expression leading to correction of the haemophilia A phenotype showing that gene transfer occurred within long-term repopulating haematopoietic stem cells. CONCLUSIONS: These results demonstrate that ectopic expression of FVIII in platelets by lentivirus-mediated bone marrow transduction/transplantation may be a promising strategy for gene therapy of haemophilia A in humans.

Tumour cell-derived exosomes endow mesenchymal stromal cells with tumour-promotion capabilities.

Mesenchymal stromal cells (MSCs) are a major component of the tumour microenvironment. A plethora of elegant studies focusing on tumour-derived MSCs have shown that they, unlike normal MSCs in other tissue, exhibit a strong ability to promote tumour progression. However, the mechanisms underlying the conversion of normal MSCs into tumour-associated MSCs are unknown. We report here a critical role of tumour cell-derived exosomes in endowing bone marrow-derived MSCs (BM-MSCs) with a tumour-favourable phenotype. Tumour cell-derived exosomes affected neither the growth factor production nor the immunosuppressive property of MSCs; rather, they endowed MSCs with a strong ability to promote macrophage infiltration into B16-F0 melanoma or EL-4 lymphoma. Ablation of macrophages by clodronate liposome administration reversed the tumour-promoting effect of MSCs educated by tumour cell-derived exosomes (TE-MSCs) on the tumour growth. By comparing the chemokine profile of BM-MSCs with that of TE-MSCs, we found that TE-MSCs produced a large amount of CCR2 ligands, CCL2 and CCL7, which are responsible for macrophage recruitment. CCR2-specific inhibitor was found to block the tumour-promoting effect of TE-MSCs. Thus, our investigations demonstrated that tumour cell-derived exosomes confer BM-MSCs the ability to enhance tumour growth. Therefore, we uncovered a novel mechanism underlying the conversion of normal MSCs to tumour-associated MSCs.

Spectroscopic study on the photoinduced reaction of fullerene C60 with aliphatic amines and its dynamics--strong short wavelength fluorescence from the adducts.

The photoinduced electron donor acceptor interactions of C60 with eight kinds of aliphatic amines, namely dicthylamine (DEA), triethylamine (TEA), tri-n-amylamine (TAA), propylethylamine (PPA), n-butylamine (BTA), n-heptylamine (HPA) and dodecylamine (DDA) and ethylenediamine (EDA) are reported by a comprehensive spectroscopic study. Experiments show that there is a good discipline with different structure and the length of n-alkyl group both in their ground and excited states. At the same time, a slow reaction takes place between C60 and various amines with a gradual increase in the concentration of various aliphatic amines or the standing of solution, which can be dramatically catalyzed by UV-radiation. The final products can all emit a strong fluorescence at the relatively shorter wavelength around 519 nm. On this basis, the dynamic properties of C60/aphaliticamines including the enthalpy of activation (deltaH++et) and entropy activation (deltaS++et), together with all sorts of influence factors are firstly investigated in this work. The possible reaction mechanisms are explored, also.

[A study on the effect of rare earth metal ions on fluorescence spectra of the tryptophan using fluorescence spectroscopy].

Rare earth metal ions and tryptophan form ion-association complex in basic medium. The complex causes fluorescence quenching of tryptophan. Fluorescence emission of tryptophan and quenching caused by rare earth metal ions both reach a climax in H3BO4-HAc-H3PO4-NaOH at pH 10 to 11, and all rare earth metal ions have the approximate effects on fluorescence quenching of tryptophan. The molecular mode of complex of rare earth metal ions and tryptophan has been founded and mechanism of fluorescence quenching has been studied in this paper.

C560Rß3 caused platelet integrin αII b ß3 to bind fibrinogen continuously, but resulted in a severe bleeding syndrome and increased murine mortality.

BACKGROUND AND OBJECTIVES: ß(3)-Deficient megakaryocytes were modified by human ß(3)-lentivirus transduction and transplantation to express sufficient levels of a C560Rß(3) amino acid substitution, for investigation of how an activated αII b ß(3) conformation affects platelets in vivo in mice. PATIENT/METHODS: As in our previous report of an R560ß(3) mutation in a patient with Glanzmann thrombasthenia, R560ß(3) murine platelets spontaneously bound antibody that only recognizes activated αII b ß3 bound to its ligand, fibrinogen. RESULTS: With this murine model, we showed that αII b -R560ß3 mutation-mediated continuous binding of fibrinogen occurred in the absence of P-selectin surface expression, indicating that the integrin was in an active conformation, although the platelets circulated in a quiescent manner. Remarkably, only 35% of R560ß(3) 'mutant' mice survived for 6 months after transplantation, whereas 87% of C560ß(3) 'wild-type' mice remained alive. Pathologic examination revealed that R560ß(3) mice had enlarged spleens with extramedullary hematopoiesis and increased hemosiderin, indicating hemorrhage. R560ß(3) megakaryocytes and platelets showed abnormal morphology and irregular granule distribution. Interestingly, R560ß(3) washed platelets could aggregate upon simultaneous addition of fibrinogen and physiologic agonists, but aggregation failed when platelets were exposed to fibrinogen before activation in vitro and in vivo. CONCLUSIONS: The results demonstrate that continuous occupancy of αIIb ß3 with fibrinogen disrupts platelet structure and function, leading to hemorrhagic death consistent with Glanzmann thrombasthenia rather than a thrombotic state.

[Separation and determination of three plant internal hormones by gas chromatography].

A method for the simultaneous separation and determination of three plant internal hormones indole acetic acid (IAA), abscisic acid(ABA) and gibberellic acid(GA) in plant by gas chromatography with wide-bore capillary column is described. The gas chromatographic conditions were as follows: FID detector; HP-1 capillary column, 5 m x 0.53 mm x 2.65 microns film; the column temperature, 220 degrees C; the injector temperature, 250 degrees C; the detector temperature, 280 degrees C, carrier gas, 3.5 mL/min N2; internal standard n-docosane. All components and internal standard were separated in 8 min. The detection limit of IAA, ABA and GA were 0.16, 0.08 and 0.48 mg/L respectively. The relative standard deviations were 2.2%, 1.7% and 2.8% respectively. The linear range were 0.16-80 mg/L(r = 0.9986), 0.08-40 mg/L (r = 0.9993) and 0.48-240 mg/L (r = 0.9991) respectively. The average recoveries were (88.4 +/- 2.4%)%, (92.2 +/- 1.2)% and (91.8 +/- 1.8)% respectively. The method is simple, rapid, sensitive and reproducible.

[Study on the direct determination of auxins by gas chromatography].

A method for the direct determination of auxins, indole acetic acid (IAA), indole-butyric acid (IBA) and naphthylacetic acid (NAA), by gas chromatography with wide-bore capillary column is described. The gas chromatographic conditions were as follows: HP-1 capillary column, 5 m x 0.53 mm i.d., 2.65 microns film, the column temperature 180 degrees C, the temperature of injector 250 degrees C, the temperature of FID detector 260 degrees C, carrier gas: N2 20 mL/min and dibutyl phthalate was used as internal standard. All components and internal standard were separated in 3 min. The relative standard deviations were from 0.61% to 1.14%. The method is simple, rapid, sensitive, good reproducible and satisfactory.

[Determination of alkaloids in pericarpium papaveris by gas chromatography with wide bore capillary column].

A method for the simultaneous determination of codeine, morphine, thebaine, papaverine and narcotine in pericarpium papaveris by gas chromatography with wide bore capillary column is described. The major components in pericarpium papaveris were extracted with methanol and chloroform by supersonic extraction and evaporation. The residue was dissolved in methanol. The resulting solution was used for analysis. The conditions for determination were: FID detector, HP-1 capillary column, 5 m x 0.53 mm x 2.65 microns film, column temperature 260 degrees C, The method requires 10 minutes for the whole analysis. The average recoveries of codeine, morphine, thebaine, papaverine and narcotine in the sample were 94.0%, 96.5%, 93.8%, 91.0% and 91.4% respectively. The relative standard deviations were from 0.92% to 2.75%. The advantages of this method are simple, rapid, accurate and sensitive.

Recognition and simultaneous determination of ofloxacin enantiomers by synchronization-1st derivative fluorescence spectroscopy.

Under controlling pH 3, R-(+)- and S-(-)-ofloxacin (OFLX) enantiomers can be well recognized and resolved by the synchronization-1st derivative fluorescence spectroscopic techniques, and the interference from urine blank also can be eliminated. The linear dynamic ranges are 0.36-2.16 (R), 0.36-2.89 and 3.16-31.6 mug/ml (S), respectively, for determining OFLX in urine samples. The limits of detection are 0.36 mug/ml (R) and the recoveries of R-(+)- and S-(-)-OFLX in urine samples are 97-104%. Relative standard deviation is <6.6%. Pharmacokinetic study of OFLX and levofloxacin shows that R-(+)- and S-(-)-ofloxacin reach their peak concentration in urine samples after a healthy subject has taken tablets for approximately 3 and 6 h, respectively. R-(+)-OFLX can be obviously detected in 5-6 h after a healthy subject has taken tablets, indicating the transformation of S-(-)- to R-(+)-OFLX enantiomer in human body (in vitro).