Surveillance for neuraminidase inhibitor resistance in human influenza viruses from Australia.

Two hundred and forty-five human influenza A and B viruses isolated in Australia between 1996 and 2003 were tested for their sensitivity to the NA inhibitor drugs, zanamivir and oseltamivir using a fluorescence-based neuraminidase inhibition assay. Based on mean IC50 values, influenza A viruses (with neuraminidase subtypes N1 and N2) were more sensitive to both the NA inhibitors than were influenza B strains. Influenza A viruses with a N1 subtype and influenza B strains both demonstrated a greater sensitivity to zanamivir than to oseltamivir carboxylate, whereas influenza A strains with a N2 subtype were more susceptible to oseltamivir carboxylate. A comparison of IC50 values for viruses isolated before and after the release of the NA inhibitors in Australia, found there was no significant difference in the sensitivity of strains to either neuraminidase inhibitor and none of the isolates tested showed clinically significant resistance.     

Skin exposure to aliphatic polyisocyanates in the auto body repair and refinishing industry: a qualitative assessment

OBJECTIVES: Although respiratory exposures have been the primary concern with isocyanates, skin exposure also can occur and may contribute to sensitization and asthma. Methodologies to assess isocyanate skin exposure in the workplace are limited and skin exposure data scarce. The goals of this study were (i) to evaluate and validate the isocyanate colorimetric indicators against a quantitative assay, (ii) to evaluate the extent of isocyanate surface contamination and skin exposure among auto body shop workers and (iii) to evaluate isocyanate skin exposure determinants. METHODS: The colorimetric indicators were compared with a high-performance liquid chromatography (HPLC) quantitative assay based on the National Institute for Occupational Safety and Health Method 5525 using paired laboratory sampling. The colorimetric indicators were then used to assess surface contamination and skin exposure to aliphatic isocyanates in 35 auto body shops and 124 workers as part of an epidemiologic study. The positive sample rate was calculated for various surfaces, body parts and tasks. The color intensity of the colorimetric indicators was rated on a scale 0 (yellow color) to 5 (deep red). Side-by-side comparisons of the qualitative method with the quantitative HPLC assay were also performed in the field using paired samples. RESULTS: Laboratory and field evaluation validated use of the colorimetric indicators. The rate of positive surface samples for isocyanates was 46% (n = 145/313). Thirty-four percent (73/216) of samples were positive for unprotected skin and 20% (n = 22/111) for skin under latex gloves. The highest positive rate observed on skin samples was obtained after paint mixing and spraying tasks. The colorimetric indicators were highly specific for isocyanates, but false negatives occurred when compared with the more sensitive HPLC quantitative assay. The presence of surface contamination and the performance of paint-related tasks were the major determinants of isocyanate skin exposure. CONCLUSIONS: This study documents extensive surface contamination and skin exposure, including under gloves, to aliphatic polyisocyanates during painting and paint mixing tasks in auto body shop workers. Contaminated surfaces and aerosol deposition during spray painting may both contribute to skin exposure. The colorimetric indicator is a quick, practical and low-cost, but not highly sensitive, industrial hygiene tool to detect isocyanate surface contamination and skin exposures following the use of isocyanate-containing products.     

Enzymatic assay of formic acid and gas chromatography of methanol for urinary biological monitoring of exposure to methanol

Summary An enzymatic assay method for the determination of urinary formic acid is described. Formic acid in urine was cleaved to carbon dioxide and water by formic acid dehydrogenase, whereby NAD⁺ was converted to NADH, which reacted with INT (p-iodonitrotetrazolium violet) in the presence of NAD-diaphorase. The color thus produced was determined at 500 nm. In addition, a simple gas chromatographic method of urinary formic acid is described, in which head space gas of formic acid methylester was applied into the wide bore column. The urinary formic acid concentrations by the enzymatic method agreed well with that by the gas chromatographic method. A simple gas chromatographic method for urinary methanol assay is also described. Acetonitrile was added to an equal volume of urine containing methanol. After centrifugation, the supernatant was injected into gas chromatography (GC). The peaks of urinary methanol and ethanol were separated by GC. Formic acid and methanol in urine of unexposed healthy subjects and workers exposed to methanol were analyzed by the colorimetric and gas chromatographic methods. Geometric mean concentrations of urinary formic acid and methanol in the healthy subjects were 7.82 mg/g creatinine and 1.34 mg/l, respectively. The concentration ratio of formic acid to methanol in the urine of the workers exposed to methanol was calculated to be 3.67 ± 2.10, which agreed with the ratio under a controlled exposure experiment. A slower excretion of formic acid than that of methanol in the urine of a volunteer was also observed.     

Synthesis and evaluation of analogues of Congo red as potential compounds against transmissible spongiform encephalopathies

The synthesis of analogues of the amyloid stain Congo red (1) as potential compounds against transmissible spongiform encephalopathies (TSEs) is reported. Using the direct method, aniline (2) or diamines such as 4,4'-diaminodiphenylsulfone (dapsone, 9), 3,3'-diaminodiphenylsulfone (10), benzidine (11), 3,3'-dimethoxybenzidine (12) or 3,3'-dichlorobenzidine (13) were diazotised to afford the corresponding diazonium salts, which without isolation, were directly used for coupling with a range of aromatic sulfonic or carboxylic acids to provide the corresponding truncated dyes analogues of Congo red, 4, 6, 8, and the symmetrical bis azoic dyes 14-19, 21-22, 24 and 26-29 as their sodium salts. Compounds were assayed in a cellular model of scrapie, a sheep TSE. Some of the compounds were shown to have similar activity to the lead compound Congo red. Molecular modelling was carried out to investigate potential structure-activity relationships (SARs) relating to the size and shape of Congo Red analogues. Within the range of compounds tested no discernible SARs were found.     

Development of a new method for the quantitative analysis of the extracellular polysaccharide of Neisseria meningitidis serogroup A by use of high-performance anion-exchange chromatography with pulsed-amperometric detection

A new method for the quantitative determination of Neisseria meningitidis group A (MenA) capsular polysaccharide (CPS) has been developed. The method is based on trifluoracetic acid (TFA) hydrolysis of the CPS (2 M at 80 degrees C for 3 h), followed by chromatographic separation and quantification of the liberated mannosamine-6-phosphate from the area of the peak obtained using an IonPac AS11 column coupled to the sensitive pulsed amperometric detector ED40. The highly selective nature of this method circumvents the interference problems associated with the classical method based on a colorimetric assay for phosphorus. Provided that suitable hydrolysis conditions can be found, this chromatographic approach might be applicable to the quantification of other bacterial antigens containing phosphorylated sugars such as meningococcal groups H, L, X and Z, and pneumococcal serotypes 6, 10A and 19.     

Effectiveness of Personal Protective Equipment and Oseltamivir Prophylaxis during Avian Influenza A (H7N7) Epidemic, the Netherlands, 2003

We analyzed the effectiveness of personal protective equipment and oseltamivir use during the 2003 avian influenza A (H7N7) epidemic in the Netherlands by linking databases containing information about farm visits, human infections, and use of oseltamivir and personal protective equipment. Using a stringent case definition, based on self-reported conjunctivitis combined with a positive hemagglutination-inhibition assay, we found that prophylactic treatment with oseltamivir significantly reduced the risk for infection per farm visit from 0.145 (95% confidence interval [CI] 0.078–0.233) to 0.031 (95% CI 0.008–0.073). The protective effect was ≈79% (95% CI 40%–97%). These results are comparable with the reported effect of prophylactic treatment with oseltamivir on human seasonal influenza. No significant protective effect was found for use of respirators or safety glasses, possibly because of limitations of the data.     

Novel multiplexed HIV/simian immunodeficiency virus antibody detection assay

Like most emerging infectious disease viruses, HIV is also of zoonotic origin. To assess the risk for cross-species transmission of simian immunodeficiency viruses (SIVs) from nonhuman primates to humans in the Democratic Republic of Congo, we collected 330 samples derived from nonhuman primate bushmeat at 3 remote forest sites. SIV prevalences were estimated by using a novel high-throughput assay that included 34 HIV and SIV antigens in a single well. Overall, 19% of nonhuman primate bushmeat was infected with SIVs, and new SIV lineages were identified. Highest SIV prevalences were seen in red-tailed guenons (25%) and Tshuapa red colobus monkeys (24%), representing the most common hunted primate species, thus increasing the likelihood for cross-species transmission. Additional studies are needed to determine whether other SIVs crossed the species barrier. With the newly developed assay, large-scale screening against many antigens is now easier and faster.     

福氏志贺菌4c亚型深圳分离株的生物学和分子特性分析

[目的]对深圳市首次分离的福氏志贺菌4c亚型菌株进行生物学和分子特性分析,了解该类新菌型生物学特征及分子特征。[方法]采用生化反应、血清学分型、刚果红侵袭试验、药敏分析等方法对患者、厨工肛拭及物体表面的17株福氏志贺菌分离株进行病原学分析,采用质粒图谱和毒力基因分析方法进行分子特性分析。[结果]所得到的福氏志贺菌4c亚型分离菌均分解葡萄糖产酸不产气,甘露醇阳性,血清学鉴定为福氏志贺菌IV型,7群菌株;刚果红侵袭试验均阳性;对氨卞西林、四环素、甲氧苄啶、阿莫西林耐药,而对阿米卡星、环丙沙星、庆大霉素、头孢噻肟、头孢噻吩和诺氟沙星敏感;所有菌株的质粒电泳图谱相同,但与F4a、F4b质粒电泳图谱差异较大;所有菌株均携带ipaH和set1基因,而仅有23.5%(4/17)的菌株携带ial和sen基因。[结论]该福氏志贺菌4c亚型深圳分离株的的生化、血清学鉴定结果与现有报道基本相符,该菌具备一定毒力。所有菌株均为同一来源,但4c亚型并非变异于F4a和F4b。ipaH和set1毒力基因携带情况与相关报道相符,ial和sen基因携带情况低于现有报道。     

Quantitative determination of saccharide in Haemophilus influenzae type b glycoconjugate vaccines, alone and in combination with DPT, by use of high-performance anion-exchange chromatography with pulsed amperometric detection

The stability and integrity of glycoconjugate vaccines requires determination of the total saccharide and quantification of the unbound or free saccharide present. The traditional assay for Hib conjugates, based on colorimetric determination of ribose, has been much improved by the use of base hydrolysis and analysis of the Hib subunit generated using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The production of this subunit was confirmed by NMR analysis. However, quantification of free Hib saccharide using this method was not possible in the combination vaccines evaluated due to interferences emanating from DPT. Thus a method based on TFA hydrolysis followed by the chromatographic separation and quantification of ribitol on a CarboPac MA1 column was developed. The method is selective, and with the use of ED40 electrode, requires only nanomole amounts for the chromatographic step, thereby ensuring that free saccharide can be monitored accurately in the formulated Hib-CRM vaccine alone and when in combination with other vaccines.     

福氏志贺菌4c亚型深圳分离株的病原特性及毒力基因分析

目的对深圳市首次分离的福氏志贺菌4c亚型菌株进行病原学分析,了解该类新菌型特征。方法采用生化反应、血清学分型、刚果红侵袭试验、药敏分析等方法对从患者、厨工肛拭及物体表面等样本中分离的17株福氏志贺菌分离株进行病原学分析,并对ipaH、ial、sen、set4个毒力基因进行PCR检测。结果所得到的17株福氏志贺菌4c亚型分离茵均分解葡萄糖产酸不产气,甘露醇阳性,血清学鉴定均为福氏志贺菌IV型、7群菌株,刚果红侵袭试验均阳性,均对氨卞西林、四环素、红霉素、甲氧苄啶、阿莫西林耐药,而对阿米卡星、环丙沙星、庆大霉素、头孢噻肟、头孢噻吩和诺氟沙星敏感,所有菌株均携带ipaH和set基因,而仅有23．53％（4／17）的菌株携带ial和sen基因。结论该福氏志贺菌4c亚型深圳分离株的生化、血清学鉴定结果与报道福氏志贺菌4c亚型基本相符,该菌具备一定毒力,ipaH和set毒力基因携带情况与相关报道相符,ial和sen基因携带情况低于现有报道。