Estimating hydrogen cyanide in forage sorghum ( Sorghum bicolor ) by near-infrared spectroscopy

Hydrogen cyanide (HCN) is a toxic chemical that can potentially cause mild to severe reactions in animals when grazing forage sorghum. Developing technologies to monitor the level of HCN in the growing crop would benefit graziers, so that they can move cattle into paddocks with acceptable levels of HCN. In this study, we developed near-infrared spectroscopy (NIRS) calibrations to estimate HCN in forage sorghum and hay. The full spectral NIRS range (400-2498 nm) was used as well as specific spectral ranges within the full spectral range, i.e., visible (400-750 nm), shortwave (800-1100 nm) and near-infrared (NIR) (1100-2498 nm). Using the full spectrum approach and partial least-squares (PLS), the calibration produced a coefficient of determination (R(2)) = 0.838 and standard error of cross-validation (SECV) = 0.040%, while the validation set had a R(2) = 0.824 with a low standard error of prediction (SEP = 0.047%). When using a multiple linear regression (MLR) approach, the best model (NIR spectra) produced a R(2) = 0.847 and standard error of calibration (SEC) = 0.050% and a R(2) = 0.829 and SEP = 0.057% for the validation set. The MLR models built from these spectral regions all used nine wavelengths. Two specific wavelengths 2034 and 2458 nm were of interest, with the former associated with C═O carbonyl stretch and the latter associated with C-N-C stretching. The most accurate PLS and MLR models produced a ratio of standard error of prediction to standard deviation of 3.4 and 3.0, respectively, suggesting that the calibrations could be used for screening breeding material. The results indicated that it should be feasible to develop calibrations using PLS or MLR models for a number of users, including breeding programs to screen for genotypes with low HCN, as well as graziers to monitor crop status to help with grazing efficiency.

[Characterization of flaxseed (Linum usitatissimum L.) grown in Venezuela]

In recent years, the consumption of flaxseed (Linum usitatissimum L.) has been promoted as a functional food for its health benefits, mainly attributable to its content of omega-3 fatty acids, lignans and dietary fiber. This study evaluated the microbiological quality, chemical composition and antioxidant properties of flaxseed grown in Venezuela and compared them to the values of a Canadian variety widely sold in the country. Total coliforms, molds and yeasts, S. aureus and sporulated of the genera Bacillus (aerobic) and Clostridium (anaerobic), moisture, fat, protein, total dietary fiber, soluble and insoluble, mucilage, minerals, fatty acid profile, equivalent HCN content, aw, color, polyphenols and antioxidant properties, like antiradical efficiency (AE), concentration of antioxidant needed to decrease the initial concentration by 50 %EC50) and the time required to reach the EC50 (TEC50) were evaluated. Significant differences in seed composition were determined, where its high content of fat, protein, alfa-linolenic acid and dietary fiber stand out. Differences were observed in the mucilage content, but not in soluble, insoluble and total fiber content. Equivalent HCN concentration in both seeds is in the order of 40 mg/100 g, which poses no health risks, considering their consumption patterns. Venezuelan flaxseed contains higher content of polyphenols than the Canadian does, but the antioxidant capacity of the latter is higher; both have an EA rated as average and a slow reaction time (TEC50 > 30 min).

CuO nanostructures as quartz crystal microbalance sensing layers for detection of trace hydrogen cyanide gas

In this work, quartz crystal microbalance (QCM) sensors for detection of trace hydrogen cyanide (HCN) gas were developed based on nanostructural (flower-like, boat-like, ellipsoid-like, plate-like) CuO. Responses of all the sensors to HCN were found to be in an opposite direction as compared with other common volatile substances, offering excellent selectivity for HCN detection. The sensitivity of these sensors is dependent on the morphology of CuO nanostructures, among which the plate-like CuO has the highest sensitivity (2.26 Hz/μg). Comparison of the specific surface areas of CuO nanostructures shows that CuO of higher surface area (9.3 m(2)/g) is more sensitive than that of lower surface area (1.5 m(2)/g), indicating that the specific surface area of these CuO nanostructures plays an important role in the sensitivity of related sensors. On the basis of experimental results, a sensing mechanism was proposed in which a surface redox reaction occurs between CuO and Cu(2)O on the CuO nanostructures reversibly upon contact with HCN and air, respectively. The CuO-functionalized QCM sensors are considered to be a promising candidate for trace HCN gas detection in practical applications.

C-type natriuretic peptide modulates quorum sensing molecule and toxin production in Pseudomonas aeruginosa

Pseudomonas aeruginosa coordinates its virulence expression and establishment in the host in response to modification of its environment. During the infectious process, bacteria are exposed to and can detect eukaryotic products including hormones. It has been shown that P. aeruginosa is sensitive to natriuretic peptides, a family of eukaryotic hormones, through a cyclic nucleotide-dependent sensor system that modulates its cytotoxicity. We observed that pre-treatment of P. aeruginosa PAO1 with C-type natriuretic peptide (CNP) increases the capacity of the bacteria to kill Caenorhabditis elegans through diffusive toxin production. In contrast, brain natriuretic peptide (BNP) did not affect the capacity of the bacteria to kill C. elegans. The bacterial production of hydrogen cyanide (HCN) was enhanced by both BNP and CNP whereas the production of phenazine pyocyanin was strongly inhibited by CNP. The amount of 2-heptyl-4-quinolone (HHQ), a precursor to 2-heptyl-3-hydroxyl-4-quinolone (Pseudomonas quinolone signal; PQS), decreased after CNP treatment. The quantity of 2-nonyl-4-quinolone (HNQ), another quinolone which is synthesized from HHQ, was also reduced after CNP treatment. Conversely, both BNP and CNP significantly enhanced bacterial production of acylhomoserine lactone (AHL) [e.g. 3-oxo-dodecanoyl-homoserine lactone (3OC12-HSL) and butanoylhomoserine lactone (C4-HSL)]. These results correlate with an induction of lasI transcription 1 h after bacterial exposure to BNP or CNP. Concurrently, pre-treatment of P. aeruginosa PAO1 with either BNP or CNP enhanced PAO1 exotoxin A production, via a higher toxA mRNA level. At the same time, CNP led to elevated amounts of algC mRNA, indicating that algC is involved in C. elegans killing. Finally, we observed that in PAO1, Vfr protein is essential to the pro-virulent effect of CNP whereas the regulator PtxR supports only a part of the CNP pro-virulent activity. Taken together, these data reinforce the hypothesis that during infection natriuretic peptides, particularly CNP, could enhance the virulence of PAO1. This activity is relayed by Vfr and PtxR activation, and a general diagram of the virulence activation cascade involving AHL, HCN and exotoxin A is proposed.

Comparison of gas chromotography, spectrophotometry and near infrared spectroscopy to quantify prussic acid potential in forages

BACKGROUND

Sorghum [Sorghum bicolor (L.) Moench] has been shown to contain the cyanogenic glycoside dhurrin, which is responsible for the disorder known as prussic acid poisoning in livestock. The current standard method for estimating hydrogen cyanide (HCN) uses spectrophotometry to measure the aglycone, p-hydroxybenzaldehyde (p-HB), after hydrolysis. Errors may occur due to the inability of this method to solely estimate the absorbance of p-HB at a given wavelength. The objective of this study was to compare the use of gas chromatography (GC) and near infrared spectroscopy (NIRS) methods, along with a spectrophotometry method to estimate the potential for prussic acid (HCNp) of sorghum and sudangrasses over three stages maturities.

RESULTS

It was shown that the GC produced higher HCNp estimates than the spectrophotometer for the grain sorghums, but lower concentrations for the sudangrass. Based on what is known about the analytical process of each method, the GC data is likely closer to the true HCNp concentrations of the forages. Both the GC and spectrophotometry methods yielded robust equations with the NIRS method; however, using GC as the calibration method resulted in more accurate and repeatable estimates.

CONCLUSION

The HCNp values obtained from using the GC quantification method are believed to be closer to the actual values of the forage, and that use of this method will provide a more accurate and easily automated means of quantifying prussic acid.

Exposure assessment through realistic laboratory simulation of a soccer stadium fire

On Sunday April 13, 2008 a fire broke out on a grandstand in the Euroborg soccer stadium in Groningen The Netherlands. The polyamide chairs on the grandstand were set on fire and supporters were exposed to the emitted smoke which induced mild health effects. The Dutch government was concerned about potential health risks that such fires could have to exposed fans. Especially the exposure to toxic fumes was considered a risk because prior research has proven that large amounts of chemical compounds are emitted during the burning of chemical substances such as polyamide. Among these emitted compounds are HCN, CO, NO(x), NH(3) and volatile organic compounds. To study if supporters were exposed to hazardous chemical compounds we designed a laboratory controlled replica of a part of the grandstand of the Euroborg stadium to perform fire-experiments. This simulation of the fire under controlled circumstances proved that a wide variety of chemicals were emitted. Especially the emission of CO and NO(x) were high, but also the emission of formaldehyde might be toxicologically relevant. The emission of HCN and NH(3) were less than expected. Exposure assessment suggests that the exposure to NO(x) is the main health risk for the supporters that were present at the Euroborg fire.

Repeatability of the measurement of exhaled volatile metabolites using selected ion flow tube mass spectrometry

Selected ion flow tube mass spectrometry, SIFT-MS, has been used to determine the repeatability of the analysis of volatile metabolites within the breath of healthy volunteers, with emphasis on the influence of sampling methodology. Baseline instrument specific coefficients of variability for examined metabolites were as follows: acetone (1%), ammonia (1%), isoprene (2%), propanol (6%), ethanol (7%), acetic acid (7%), and hydrogen cyanide (19%). Metabolite concentration and related product ion count rate were identified as strong determinants of measurement variation. With the exception of ammonia, an orally released metabolite, variability in repeated on-line breath analysis tended to be lower for metabolites of systemic origin. Standardization of sampling technique improved the repeatability of the analysis of selected metabolites. Off-line (bag) alveolar breath sampling, as opposed to mixed (whole) breath sampling, likewise improved the repeatability of the analysis of all metabolites investigated, with the exception of acetic acid. We conclude that SIFT-MS analysis of common volatile metabolites within the breath of healthy volunteers is both reliable and repeatable. For selected metabolites, the finding that repeatability is improved through modification of sampling methodology may have implications in terms of future recommended practices.

Determination of hydrogen cyanide in cigarette mainstream smoke by LC/MS/MS

An LC/MS/MS method is presented for the determination of hydrogen cyanide in cigarette mainstream smoke. Cyanide is derivatized with 2,3'-naphthalenedicarboxaldehyde and taurine to form a benzo[f]isoindole derivative, which is then analyzed by LC/MS/MS. Isotopic KCN (K13C15N) was used as an internal standard. The regression equation was linear within the range 2.4-331 ng/mL for cyanide with a correlation coefficient > 0.999. The LOD was calculated as 4.1 ng/cigarette. The influence of the sodium hydroxide trapping solution concentration on the results is discussed. A 1 M solution showed the best results in terms of sample stability and trapping efficiency. The method proved to be robust, reliable, and more selective than current methods, making it a logical choice for determination of total cyanide in cigarette smoke.

Tropospheric trace gases at Bremen measured with FTIR spectrometry

The total column densities of acetylene (C(2)H(2)), carbon monoxide (CO), hydrogen cyanide (HCN) and ethane (C(2)H(6)) measured in Bremen (Germany, 53.107 degrees N, 8.854 degrees E) were compared with data from Mace Head/Ireland (MHD) and GEOS-Chem model simulations. The data were obtained between August 2002 and October 2006 with the ground based high resolution Fourier Transform Infra-Red (FTIR) Spectrometry, using the sun as the light source. The analysis showed good agreements between all the three data sets for the seasonal cycle of CO. Enhancements in summer 2003 and summer 2004 due to influence of biomass burning were identified in all three data sets. The high correlations between C(2)H(6) and C(2)H(2), C(2)H(2) and CO, and for C(2)H(6) and CO support the similarities in their sources and sinks. The results suggest that the background air in Bremen is mainly influenced by long-ranged transport of biomass burning products. Local pollution plays a minor role for the measurements performed in Bremen.

[Acute encephalopathy caused by cyanogenic fungi in 2004, and magic mushroom regulation in Japan]

Two topics, related to mushroom poisoning of recent interest in Japan, have been presented. In autumn 2004, 59 cases of acute encephalopathy were reported across 9 prefectures in Japan (24 from Akita Prefecture with 8 deaths; age 48-93, average 70; female 14, male 10). Of 24 cases, 20 had kidney dysfunction. Four poisoned subjects showed no kidney trouble. Of the 24 poisoning cases, 23 people ate Pleurocybella porrigens, and one ate Grifola frondosa. The latter subject (female, late 40's) was receiving dialysis for more than 35 years. In August, she felt dizziness, headache and tinnitus. She visited hospital and asked to stay there. In the hospital she ate 5g of stewed G. frondosa and 10g of the same fungus boiled with chicken and taro on different days. Fourteen to 18 days after the eatings, she developed cramps and lost consciousness, and fell into a coma. Her cramp and coma continued for about 10 days almost until her death. Her symptoms caused by G. frondosa were similar to those observed for the above 23 cases of P. porrigens ingestion. Therefore, we concluded that encephalopathy experienced in Akita Prefecture caused by was the cyanogenic fungi such as P. porrigens , G. frondosa, Pleurotus eringii etc. Although the amounts of mushrooms eaten by poisoned subjects were not so clear, we estimated that the amounts of hydrogen cyanide (HCN) taken into human bodies exceeded the detoxication limit of HCN, resulting in HCN poisoning. However, it has not been proved that the encephalopathy is directly or indirectly caused by the HCN poisoning. Many typhoons came across Japan and landed 10 times in 2004, and mushroom size was larger than usual one, and HCN contents in fruit-bodies seemed to be increased especially in the late-stage of their growth. Thirteen species of magic mushrooms were prohibited by the law from 2002 in Japan. They include Copelandia (Panaeolus) cyanescens, Panaeolus papilionaceus, Panaeolus sphinctrinus, Panaeolus subbalteatus, Psilocybe argentipes, Psilocybe cubensis, Psilocybe fasciata, Psilocybe lonchophorus, Psilocybe subaeruginascens, Psilocybe subcaerulipes, Psilocybe subcubensis, Psilocybe tampanensis, and Psilocybe venenata.

New approach for data evaluation of industrial wastewater treatment plant: methodology and case study for a coke and steel-processing plant

Environmental monitoring of biological wastewater treatment plants (BWWTP) treating industrial effluents produces large amount of data. Frequent sampling is done in the influent and effluent but also in intermediate points. Samples are analyzed for classical and specific contaminants and physical-chemical parameters are monitored. In this paper data from a BWWTP treating the effluents of a coke and steel-processing factory are analyzed. Due to a complex situation, this BWWTP gave poor performances that did not match environmental regulations, meanwhile upgrading proved to be uneasy. Data analysis using principal component analyses (PCA) or kinetic modeling with a Haldane model was unsuccessful in handling these data, which was attributed to undetermined toxic effects. A new methodology is reported, that allowed to identify a kinetics for thiocyanate degradation and a relation between pH and toxic effects. This analysis of the plant data allowed to make hypothesis on the process control parameters and to recommend management modifications, allowing a further increase of the performances.

Report of the investigation committee into the cyanide poisonings of Providence firefighters

In the afternoon of March 23, 2006 a Providence firefighter was diagnosed as having cyanide poisoning after working at a building fire. In the aftermath of three fires at commercial and residential sites that day, eight additional firefighters (out of 28 tested) were found to have elevated levels of cyanide. Numerous other members reported symptoms consistent with cyanide poisoning, including headaches, weakness and fatigue, nausea, and shortness of breath. The Providence Fire Department (PFD) established a joint union management committee to review the situation.

Influence of soil reaction on diversity and antifungal activity of fluorescent pseudomonads in crop rhizospheres

The diversity and antifungal activity of fluorescent pseudomonads isolated from rhizospheres of tea, gladiolus, carnation and black gram grown in acidic soils with similar texture and climatic conditions were studied. Biochemical characterisation including antibiotic resistance assay, RAPD and PCR-RFLP studies revealed a largely homogenous population. At soil pH (5.2), the isolates exhibited growth with varying levels of siderophore production, irrespective of crop rhizospheres. Two isolates with maximum chitinase production showed antagonism. The bacterial populations in general lacked the ability to produce deleterious traits such as cellulase, pectinase and hydrogen cyanide. However, increased pH levels beyond 5.2 caused reduction in metabolite production with reduced antifungal activity. The homogeneity of the bacterial population irrespective of crop rhizospheres together with decreased secondary metabolite production at higher pH levels reinstated the importance of soil over host plant in influencing rhizosphere populations. The studies also yielded acid tolerant chitinase producing antagonistic fluorescent pseudomonads.

Hydrogen cyanide exhaust emissions from in-use motor vehicles

Motor vehicle exhaust emissions are known to contain hydrogen cyanide (HCN), but emission rate data are scarce and, in the case of idling vehicles, date back over 20 years. For the first time, vehicular HCN exhaust emissions from a modern, in-use fleet at idle have been measured. The 14 tested light duty motor vehicles were operating at idle as these conditions are associated with the highest risk exposure scenarios (i.e., enclosed spaces). Vehicular HCN was detected in 89% of the sampled exhaust streams and did not correlate with instantaneous air-fuel-ratio or with any single, coemitted pollutant. However, a moderate correlation between HCN emissions and the product of carbon monoxide and nitric oxide emissions was observed under cold-start conditions. Fleet average, cold-start, undiluted HCN emissions were 105 +/- 97 ppbV (maximum: 278 ppbV), whereas corresponding emissions from vehicles operating under stabilized conditions were 79 +/- 71 ppbV (maximum: 245 ppbV); mean idle fleet HCN emission rates were 39 +/- 35 and 21 +/- 18 microg-min(-1) for cold-start and stabilized vehicles, respectively. The significance of these results is discussed in terms of HCN emissions inventories in the South Coast Air Basin of California and of health risks due to exposure to vehicular HCN.

COMPOSITION OF VOLATILE ORGANIC COMPOUNDS IN DIATHERMY PLUME AS DETECTED BY SELECTED ION FLOW TUBE MASS SPECTROMETRY

BACKGROUND

There is some evidence that surgical plume may pose a risk to health professionals, but the risks posed by volatile organic compounds have not been thoroughly investigated.

METHODS

The composition of volatile organic compounds in diathermy plume produced during surgery was analysed by selected ion flow tube mass spectrometry.

RESULTS

Hydrogen cyanide (3-51 parts per million), acetylene (2-8 parts per million), and 1,3-butadiene (0.15-0.69 parts per million) were identified in the plume.

CONCLUSION

Although there is no evidence of adverse health effects from the volatile organic compound in diathermy plume, the evidence that it is safe to breathe this plume is lacking. Therefore, we would recommend the use of smoke evacuators where practical.

Carboxyhemoglobin and thiocyanate as biomarkers of exposure to carbon monoxide and hydrogen cyanide in tobacco smoke

The determination of biomarkers in human body fluids is a useful tool, which allows the quantitative assessment of the exposure to chemicals or complex mixtures of chemicals and of early biological effects as a result of the exposure. Biomarkers require validation before their successful application in human studies. This review describes some general purposes of human biomonitoring and biomarkers including the requirements for validation. Risk assessment and harm reduction of smoking and tobacco products, respectively, is a very suitable field for the application of biomarkers. A brief historical review shows that the application of biomarkers of exposure and effect in human smoking goes back more than 150 years. Two 'classical' biomarkers of exposure to tobacco, namely carboxyhemoglobin (COHb and its equivalent carbon monoxide in exhalate, COex) and thiocyanate (SCN) in body fluids are discussed in terms of sources of exposure, metabolism, disposition kinetics and influencing host factors. Data on COHb/COex and SCN in nonsmokers and smokers as well as the power to discriminate between smokers and nonsmokers are presented. Both biomarkers are significantly correlated with the daily cigarette consumption. Smoking machine-derived yields of the precursors carbon monoxide and hydrogen cyanide were not correlated with COHb/COex and SCN, respectively. It is concluded that, while COHb/COex is a useful biomarker for assessing the smoke inhalation, preferably in controlled studies, the application of SCN in body fluids as a biomarker for smoking is limited, mainly due to the abundance of other sources for SCN.

Phenotypic plasticity of cyanogenesis in lima bean Phaseolus lunatus-activity and activation of beta-glucosidase

Cyanogenesis, the release of toxic HCN from damaged plant tissues, is generally considered as a constitutive plant defense. We found phenotypic plasticity of cyanogenesis in young leaves of lima bean Phaseolus lunatus based on increased activity of the beta-glucosidase in response to herbivore attack. Two aspects of plant cyanogenesis have to be considered in ecological analyses: (1) the cyanogenic potential (HCNp), which indicates the total amount of cyanide-containing compounds present in a given tissue, and (2) the cyanogenic capacity (HCNc), representing the release of HCN per unit time. This release is catalyzed by specific beta-glucosidases, whose activity is a crucial parameter determining overall toxicity. Enzymatic activity of beta-glucosidase-and, in consequence, the rate of HCN release-was increased significantly after 72 hr of incubation with spider mites as compared to non-infested leaves. Feeding by L1 larvae of Mexican bean beetles also led to enhanced enzymatic activity, whereas mechanical damage of leaf tissue had no effect on beta-glucosidase activity and the release of HCN. The results place plant cyanogenesis in the group of induced resistance traits, whose degree of activity depends on the feeding by a particular herbivore.

Glass distilling collector applied for HCN recovery from submerged culture broth and fruiting body of Pleurotus eryngii for identification and quantification

Detection and surveillance of food commodities containing cyanide is a crucial issue of food safety. In this study, five strains of Pleurotus eryngii (P. eryngii) were grown in submerged culture of yeast malt broth (YMB) with the suspected production of HCN. A safety-warranted U-bent glass distilling collector with three enlarged bulbs on each arm was designed to recover the broth vapor. When AgNO(3) solution was used as an absorbent to interact with the vapor, a white precipitate was formed. The precipitate was isolated and identified as AgCN by FT-Raman spectroscopic analysis. When the absorbent was substituted by KOH, after evaporation to dryness, dissolved in D(2)O, and followed by (13)C-NMR analysis, a KCN spectrum was achieved. Formation of AgCN and KCN confirmed HCN production in the broth by P. eryngii. When a sodium picrate solution (1.4%) was used as an absorbent and various authentic KCN solutions were applied for distillation and followed by absorbance determination at 510 nm, a linear dose-dependent relationship was obtained and the procedure was applied for HCN quantification of the marketed P. eryngii mushrooms (fruiting body). As estimated, 67.3% of the products contained HCN less than 1.0 mg/kg, 17.3% between 1.0 and 2.0 mg/kg, and 15.4% higher than 2.0 mg/kg. When the mushrooms were sliced and cooked in water at 95 degrees C for 6 min, 89.1% of the original HCN was lost. When the P. eryngii strains were respectively grown by submerged cultivation in YMB or YMB supplemented with 2.5% glycine for 16 days, HCN content was slightly higher in the latter than in the former for each strain.

Complex organic matter in Titan's atmospheric aerosols from in situ pyrolysis and analysis

Aerosols in Titan's atmosphere play an important role in determining its thermal structure. They also serve as sinks for organic vapours and can act as condensation nuclei for the formation of clouds, where the condensation efficiency will depend on the chemical composition of the aerosols. So far, however, no direct information has been available on the chemical composition of these particles. Here we report an in situ chemical analysis of Titan's aerosols by pyrolysis at 600 degrees C. Ammonia (NH3) and hydrogen cyanide (HCN) have been identified as the main pyrolysis products. This clearly shows that the aerosol particles include a solid organic refractory core. NH3 and HCN are gaseous chemical fingerprints of the complex organics that constitute this core, and their presence demonstrates that carbon and nitrogen are in the aerosols.

[The trial of simple gas analysis of tobacco smoke that can be used for medical education]

OBJECTIVE

The purpose of this study was to check a simple sampling and easy gas analysis of tobacco smoke for effective tobacco intervention in medical education.

METHODS

The mainstream of tobacco smoke was sampled by a syringe (50 ml) at five, ten and twenty seconds. The extracted mainstream was moved to a commercial PET bottle (2000 ml), and measured with gas detector tubes. The sidestream, which rises from the tip of the cigarette, was collected into a commercial PET bottle for a duration of 30 or 60 seconds. Formaldehyde, acetaldehyde, ammonia, hydrogen cyanide, and nitrogen oxides (NO, NO2) in the tobacco smoke were measured. Then, these gasses in the tobacco smoke of four brands of cigarettes were compared. This trial was conducted in third-year medical students, and the changes in attitudes to smokers and tobacco itself were investigated.

RESULTS

The method of sampling 50 ml for 5 seconds produced the highest concentration of each gas in the mainstream. The gas concentration in the sidestream increased as the sampling time increased. The gas concentration in mainstream of "Lucia" was the highest of the used four brands, and the gas concentrations in the sidestream of "Mild Seven Prime" were higher than those of the other brands. Many medical students obtained knowledge about the toxicity of smoking by this experiment study.

CONCLUSION

We studied a simple sampling method of tobacco smoke, and gas analysis with gas detector tubes. This method is recommended for tobacco education and intervention in medical education.

Detection of volatile compounds emitted by Pseudomonas aeruginosa using selected ion flow tube mass spectrometry

Pseudomonas aeruginosa (PA) is associated with a distinctive smell produced by a combination of volatile compounds (VCs). Selected ion flow tube mass spectrometry (SIFT-MS) provides a novel and rapid methodology for rapid, accurate detection of trace quantities (parts per billion; ppb) of VCs in air. We studied the VCs produced by different isolates of PA cultures in vitro from patients with cystic fibrosis. Twenty-one patients with cystic fibrosis provided sputum and cough swab samples for culture. These were used to inoculate blood agar (BA) and Pseudomonas-selective media (PSM). These plates were incubated for 48 hr at 37 degrees C inside sealed plastic bags. The air surrounding the samples after 48 hr (headspace) was analyzed using SIFT-MS. PA growth was commonly associated with the production of significant quantities of VCs, notably hydrogen cyanide gas (HCN). This was detectable in the headspace of 15/22 of PA-positive samples. In contrast, it was only seen in the headspace of 1/13 control samples (6 sterile plates and 7 plates with only mixed upper respiratory tract flora). The concentration of HCN was significantly higher above PA-positive samples than above other bacterial growth (P < 0.01), and in our study, levels of HCN greater than 100 ppb were a sensitive (68%) and highly specific (100%) biomarker of PA. SIFT-MS can detect a range of VCs from PA in vitro. HCN may be a specific indicator of PA infection in vivo, and offers promise as a biomarker for noninvasive detection of PA infection by breath analysis.

Retrospective trends and current status of ethyl carbamate in German stone-fruit spirits

Ethyl carbamate (urethane, C(2)H(5)OCONH(2)) is a known genotoxic carcinogen of widespread occurrence in fermented food and beverages with highest concentrations found in stone-fruit spirits. Between 1986 and 2004, 631 cherry, plum or mirabelle (yellow plum) spirits were analysed for ethyl carbamate using gas chromatography in combination with mass spectrometry after extrelut extraction. The ethyl carbamate concentration of the samples ranged between 0.01 mg l(-1) and 18 mg l(-1) (mean 1.4 mg l(-1)). After exposure of the samples to UV light, significantly (p=0.001) higher concentrations between 0.01 mg l(-1) and 26 mg l(-1) (mean 2.3 mg l(-1)) were found. The ethyl carbamate concentration increased on average by 1.3 mg l(-1). A linear correlation between the year of sampling and ethyl carbamate concentration showed a statistically significant but very slight decrease (R=-0.10, p=0.024). However, if only samples which officially were non-compliant were considered exceeding the upper limit of 0.4 mg l(-1) more than twice, a significant reduction (R =-0.56, p=0.018) of the quota was evident. This shows that measures to reduce ethyl carbamate were successfully introduced in many distilleries. However, nearly 20 years after the first warnings about ethyl carbamate in spirit drinks, the problem persists especially in products derived from small distilleries. During experimental production of stone-fruit spirits using state-of-the-art technologies, it was shown that the occurrence of ethyl carbamate in stone fruit spirits is preventable. Even for small distilleries, simple possibilities like destoning exist to minimize the ethyl carbamate content.