First isolation of Francisella tularensis subsp. tularensis in Europe

Francisella tularensis subsp. tularensis is the common causal agent of tularemia in the USA and Canada, while F. tularensis subsp. palaearctica (holarctica) occurs in Europe, Asia, and to a minor extent in North America. F. tularensis subsp. mediaasiatica was found only in central Asia in a part of the former Soviet Union. Of the total of 155 F. tularensis strains isolated over the years 1978–1996 during the surveillance of tularemia in Slovakia, 65 were from small mammals, 68 from ticks and 22 from mites and fleas. They were characterized and classified by basic markers of infraspecific taxonomy in tests in vitro and compared with type strains of three subspecies and biovars of F. tularensis. Comparative studies have revealed biological properties characteristic of F. tularensis subsp. tularensis in 17 strains isolated from fleas and mites parasiting on small terrestrial mammals, collected in the Danube region, near Bratislava. These strains fermented glycerol, glucose, were positive for citrulline ureidase and sensitive to erythromycin, in contrast to the other 138 isolates classified as F. tularensis subsp. palaearctica (holarctica), biovar II, which fermented only glucose, were negative for citrulline ureidase and resistant to erythromycin. Two selected pairs of isolates with properties characteristic of F. tularensis subsp. palaearctica (holarctica), biovar II (SE-210, SE-234) and of F. tularensis subsp. tularensis (SE-219, SE-221), as shown in tests in vitro, were further examined for their pathogenicity on white mice, guinea pigs and domestic rabbits. In tests of virulence on domestic rabbits, the isolates SE-210 and SE-234 had low pathogenicity, while the isolates SE-219 and SE-221 exhibited high pathogenicity, which along with their biochemical properties confirmed their identification as strains of F. tularensis subsp. tularensis. The first findings of the highly virulent strains of F. tularensis subsp. tularensis in Europe indicate a serious event from epidemiologic and epiozootologic aspects, requiring systematic surveillance.     

聚合物空心纳米球及其在药学领域的应用

概述聚合物空心纳米球的制备和表征检测方法以及作为给药载体在药学领域的应用.聚合物空心纳米球用作载药系统具有独特优势,除了具有靶向性和控、缓释性,它还可提高载药量、药物生物利用度及系统稳定性.     

Isolation and characterization of cellulose from date palm tree spathe sheath

This study deals with a series of operations to isolate the micro-cellulose from the palm tree spathe sheath by using a modified chemical method to take into account the low cost and the completion speed and its characterization using X-ray diffraction technique (XRD), infrared spectroscopy (FTIR) and scanning electron microscope coupled with element analyzer (SEM/EDX). The results showed that the extraction method succeeded in obtaining very pure microscopic fibers with a width of 2–10 μm with a crystallinity index equal to 79.21%, containing the two cellulose features Iβ and II, that, the conversion ratio of the first to the second was estimated at 32, 87%.     

Compressional Characterization of Two Dextrose-Based Directly Compressible Excipients Using an Instrumented Tablet Press

The main objective of this work was to evaluate the compaction behavior and record the work and the force involved in the compaction of blends and granules of two dextrose-based directly compressed excipients using a single-punch instrumented tablet press. The second objective was to identify the predominant form of deformation for the two different directly compressible excipients. Anhydrous theophylline (10% w/w) was used as a drug model, Emdex and/or Maltrin M 510 (89.5% w/w) were used as diluent, and magnesium stearate (0.5% w/w) was used as lubricant. All formulations were compressed at four different compressional forces and at a target tablet weight of 450 mg ± 5%. Results show that compacts prepared from Emdex using the direct compression method produced the lowest elastic work and die wall friction, and the best degree of lubrication. Wet granulation for Maltrin M 510 decreased elastic work, frictional work, and ejection force, and enhanced both net work and degree of lubrication. In general, wet granulation for both Emdex and Maltrin M 510 decreased the crushing strength of the tablets and enhanced the degree of lubrication, compared to direct compression formulations. All formulations showed similar shape pattern for plastic deformation, suggesting that the predominant mechanism of deformation is plastic deformation type a Heckel plots.     

Purification of hemorrhagic SVMPs from venoms of three vipers of Egypt

Three viper P-III hemorrhagic SVMPs: EpyHTI (60 kDa), EcoHTI (60 kDa) and CcHTI (58 kDa) of the most dangerous vipers Echis pyramidum, Echis coloratus and Cerastes cerastes, respectively were purified and characterized in a set of biochemical assays. The SVMPs were purified by applying a protocol of three successive chromatographic steps. The enzymatic activity of the purified SVMPs was stimulated by the divalent cations Ca²⁺, Mg²⁺ and inhibited by metalloproteinase inhibitors and (Zn²⁺, Mn²⁺, Ni²⁺, Co²⁺, Cu²⁺ and Hg²), whereas inhibitors of serine and cysteine proteinases had no effect. The digestion of the BM proteins by purified SVMPs was much different, indicating different cleavage specificity for each of the purified SVMPs. Based on their intense hemorrhagic activity and molecular masses, the purified enzymes were hypothesized to belong to the P-III class of SVMPs. The three SVMPs possess close biochemical properties, but are different with respect to cleavage site, (fibronectin and fibrinogen). Furthermore, the described purification procedure allows simple preparation of appreciable quantities of the three SVMPs for further studies.     

A nanoparticulate drug-delivery system for glaucocalyxin A: formulation,characterization, increased in vitro,and vivo antitumor activity

Glaucocalyxin A (GLA) is a phytochemical component with multiple pharmacological activities; however, glaucocalyxin A's wider use has been restricted by its poor solubility. In this study, GLA nanosuspensions were prepared with precipitation-combined ultrasonication and were characterized by dynamic light scattering (DLS), transmission electron microscope (TEM), and differential scanning calorimetry (DSC). The GLA nanosuspensions were spherical with a smooth surface and a small size of 143?nm, the drug payload achieved 8.95%, and the maximum GLA concentration reached 1?mg/mL. The lyophilized powders for the GLA nanosuspensions were amorphous and displayed a biphasic drug release pattern with an initial burst release and a consequent sustained release. In contrast to the free drug solution, GLA nanosuspensions showed higher in vitro antitumor activity against HepG2 cells (IC₅₀ value of 1.793 versus 2.884?μg/mL at 24?h, p?<?0.01). Meanwhile, nanosuspensions displayed better anticancer efficacy than free GLA on H22 bearing mice (54.11% versus 36.02% tumor inhibition rate). These results indicate that GLA nanosuspensions have great potential for the treatment of hepatic cancer.     

紫球藻凝集素的糖蛋白特性

从紫球藻中纯化出紫球藻凝集素(PCL)。经测定该凝集素是一种分子量为39.6kD的糖蛋白,分子中含有28.4%的中性糖。氨基酸组成中缬氨酸(Val)含量最高,异亮氨酸(Iie)含量最低。PLC能凝集兔与猪的红细胞,其凝血活性可被某些单糖或二糖及胃粘蛋白所抑制。PLC对温度变化较为敏感,对酸、碱处理有较好的稳定性。     

Validated stability-indicating HPLC method for the determination of pridinol mesylate. Kinetics study of its degradation in acid medium

The stability of pridinol mesylate (PRI) was investigated under different stress conditions, including hydrolytic, oxidative, photolytic and thermal, as recommended by the ICH guidelines. Relevant degradation was found to take place under acidic (0.1N HCl) and photolytic (visible and long-wavelength UV-light) conditions, both yielding the product resulting from water elimination (ELI), while submission to an oxidizing environment gave the N-oxidation derivative (NOX). The standards of these degradation products were synthesized and characterized by IR, (1)H and (13)C NMR spectroscopy. A simple, sensitive and specific HPLC method was developed for the quantification of PRI, ELI and NOX in bulk drug, and the conditions were optimized by means of a statistical design strategy. The separation employs a C(18) column and a 51:9:40 (v/v/v) mixture of MeOH, 2-propanol and potassium phosphate solution (50mM, pH 6.0), as mobile phase, delivered at 1.0 ml min(-1); the analytes were detected and quantified at 220 nm. The method was validated, demonstrating to be accurate and precise (repeatability and intermediate precision levels) within the corresponding linear ranges of PRI (0.1-1.5 mg ml(-1); r=0.9983, n=18) and both impurities (0.1-1.3% relative to PRI, r=0.9996 and 0.9995 for ELI and NOX, respectively, n=18). Robustness against small modifications of pH and percentage of the aqueous mobile phase was ascertained and the limits of quantification of the analytes were also determined (0.4 and 0.5 microg ml(-1); 0.04% and 0.05% relative to PRI for ELI and NOX, respectively). Peak purity indices (>0.9997), obtained with the aid of diode-array detection, and satisfactory resolution (R(s)>2.0) between PRI and its impurities established the specificity of the determination, all these results proving the stability-indicating capability of the method. The kinetics of the degradation of PRI in acid medium was also studied, determining that this is a first-order process with regards to drug concentration, with an activation energy of 25.5 Kcal mol(-1) and a t(1/2)=10,830 h, in 0.1N HCl at 38 degrees C.     

医疗器械生物材料表征和化学性能检测的重要性

医疗器械生物学评价国际标准ISO10993第18和19部分作为医疗器械和生物材料生物学评价的重要组成部分越来越受到重视,在安全性评价中的重要一环就是材料的表征和材料中可萃取和迁移成分的鉴定。本文讨论那些试验可以满足这些要求。     

Simultaneous characterization and quantitation of 11 coumarins in Radix Angelicae Dahuricae by high performance liquid chromatography with electrospray tandem mass spectrometry

A high performance liquid chromatography with electrospray tandem mass spectrometry (HPLC–ESI-MS/MS) method has been developed to characterize and quantify 11 coumarin compounds in Radix Angelicae Dahuricae simultaneously. By using this HPLC–ESI-MS/MS method, all 11 coumarins were separated and determined within 10 min. These coumarins were detected by ESI⁺ ionization method and quantified by multiple reaction monitor (MRM). The linear regressions were acquired with r² > 0.995, respectively. The precision was evaluated by intra- and inter-day tests, and relative standard deviation (R.S.D.) values were reported within the range of 1.14–4.42% and 0.37–4.00%. The recovery studies for the quantified compounds were observed over the range of 92.1–105.6% with R.S.D. values less than 4.55%. It demonstrated that the method developed was successfully applied for identification and quantification of 11 coumarins in Radix Angelicae Dahuricae. The results showed that the contents of coumarins in Radix Angelicae Dahuricae were processed differently and varied significantly.