Volumen 19 (2000): Edición 2 (July 2000)

The Internet is a potent medium for the global distribution and retrieval of information in all areas of life. We already profit from this opportunity and will do so even more when the Internet will be developed further. But there is another side to all this: The fact that unchecked information is available to an almost unlimited extent also carries dangers with it particularly when it is given the semblance of being based on scientific evidence. For the publication of scientific knowledge, an efficient control system has matured and proved successful over many years: peer review. The Internet is not the only medium to dodge this system, but the Internet is certainly the cheapest, fastest, most widespread and therefore the most efficient (and probably dangerous) way to do so. A recent example is Arpad Pusztai's claim in the press and on television programmes in Great Britain that genetically modified (GM) potatoes may stunt the growth of rats. His ‘findings', although not published in a peer-reviewed journal, were welcomed and exploited by lobby groups and triggered widespread concern over the issue of GM food. A year later the paper was published in The Lancet accompanied by a critical commentary (A. Pusztai: Lancet 354 (1999) 1314-1315). One benefit of the publication in this prestigious journal certainly was that Pusztai had to retract his original claims because the data simply do not support them (N. Loder: Nature 401 (1999) 731).A similar case, we believe, is the Internet publication of July 14, 1999, on the website of ‘Action on Smoking and Health’ (ASH) entitled ‘Tobacco Additives - Cigarette Engineering and Nicotine Addiction', authored by C. Bates, M. Jarvis and G. Connolly (http://www.ash.org.uk/papers/additives.html). In this report, the authors claim, among other things, that the cigarette industry uses pharmacologically active additives in order to influence the smoking behaviour. The scientific evidence for their claim is mainly based on notes and memos from scientists of the tobacco industry which are also available on the Internet. As in the example discussed above, the ASH paper achieved a widespread coverage in the media, impressing not only the public but also government bodies, thus certainly serving its intended purpose. It is our view that legislation based on (or at least influenced by) dubious scientific evidence is harmful not only for the industry but even more for those who are supposed to be protected, the consumers. We, therefore, believe that the invited Commentary by L. Mueller and W. Roeper (see page 51) on only a few aspects of the ASH paper on additives is of interest for our readers. The Mini-Review by Dixonet al. (page 103) in appropriate scientific depth tackles the problem of nicotine transfer from tobacco to the smoker and the role of ammonia compounds used in the production of cigarettes. This Mini-Review is the first of a series of peer-reviewed, ‘state-of-the-art’ overviews on issues of current interest in tobacco research. The Mini-Review will present its subject as a complete scientific manuscript accompanied by headlines allowing a quick overview of the main issues. Furthermore, we as editors of BeiträgezurTabakforschung International take the liberty but also the responsibility to invite experts to write Commentaries on selected topics. Commentaries represent scientifically based views of the authors and are intended to encourage further scientific discussion. Allenet al. (Nature: 402 (1999) 722) reported on the overall reliability of scientific information on websites and found that a high percentage was ‘misleading', ‘inaccurate’ and ‘unreferenced'. Nonetheless, the authors recognize the substantial advantages of the Internet as a resource for scientific information provided that peer review is maintained as the guiding principle for evaluating science. We deeply regret that the circulation of our journal is not sufficient to correct this kind of misinformation. In order to at least partly remedy this disadvantage, but also for other reasons, we as editors of BeiträgezurTabakforschung International are considering a full-text Internet version (besides the printed version) of this journal to be implemented in the year 2001. In consideration of our comments above, we, however, want to assure our readers that the Beiträge will retain its peer-review system.

The following is a line-up of the allegations made by C. BATES, M. JARVIS and G. CONNOLLY in “Tobacco Additives - Cigarette Engineering and Nicotine Addiction” (1). These allegations are not in agreement with the facts reported in the scientific literature (2-18).

It is important to know how tobacco additives behave when cigarettes are smoked, whether they transfer intact to the smoke or whether there is any decomposition during smoking. Pyrolysis-GC-MS is a technique that can be focussed upon the effects of combustion from a single material free from interference from the complex mixture of different components present in the smoke. However, because pyrolysis is a model technique, the results need to be validated by comparison with cigarette smoke chemistry. In a previous paper we presented such a method for modelling the smoke chemistry from a burning cigarette using pyrolysis-GC-MS. The transfer and the extent of degradation of anisole, p-anisaldehyde, benzaldehyde, isoamylisovalerate, methyl trans-cinnamate and vanillin within a burning cigarette were estimated using this pyrolysis method. When these data were compared with results from smoke studies from ¹⁴C-analogues of the materials, the high levels of transfer predicted by pyrolysis were found to be generally consistent with the smoke chemistry data. However, there were still two outstanding issues. Firstly, there was some ambiguity in the labelled study about whether vanillin actually transferred without degradation or not. Furthermore, the results from the ¹⁴C-labelled study showed a greater extent of degradation for p-anisaldehyde than that indicated from the pyrolysis experiments. The purpose of the current study was to present some new information obtained to address these questions by better understanding the effect upon the smoke chemistry from adding vanillin and p-anisaldehyde, and the relationship between the smoke chemistry and the pyrolysis results. Components were identified in the smoke from cigarettes loaded with p-anisaldehyde and vanillin labelled with ¹⁸O and ¹³C. The extent of degradation from each additive was estimated by identifying labelled degradation products in the smoke. Because there was a clear distinction between the mass spectra from the labelled compounds and their natural counterparts, the major degradation products from the labelled compounds could be readily identified in the chromatograms of the corresponding smoke extracts. Evidence of some degradation at above the transfer temperature was indicated for both additives. The amount of degradation was found to be less than 1% for p-anisaldehyde and only 0.1% for vanillin. This low level of degradation was acceptably consistent with the intact transfer values of 97% and 100%, respectively, obtained by pyrolysis.

In the August 1997 issue of Environmental Science&Technology (ES&T), PANKOW and co-workers at the Oregon Graduate Institute reported that the addition of ammonia-containing additives to cigarette tobacco increased the amount of unprotonated nicotine in cigarette mainstream smoke (MSS) and thus increased the bioavailability of nicotine to the smoker. Articles about PANKOW's work also appeared in other publications along with allegations that ammonia-containing additives are used to manipulate nicotine deliveries. However, initial review of PANKOW's research and that reported on environmental tobacco smoke (ETS) in an earlier paper showed that potentially serious issues existed with PANKOW's experimental data and conclusions. Consequently, a critical assessment of PANKOW's research and the underlying theories of gas/particle partitioning was undertaken. This assessment confirmed that PANKOW and his co-workers made a number of errors not only in their determinations of the gas/particle partitioning coefficients for nicotine in MSS and ETS but also in the interpretations of the data. During the preparation of this assessment, data from other researchers became public. These data showed that there was no correlation between tobacco ammonia (including residual ammonia from the use of ammonia-containing additives) and MSS ammonia deliveries and MSS smoke pH, and that the amount of unprotonated nicotine in the undiluted MSS of a full flavor (FF) American filter cigarette was less than 0.1%. These new data fully substantiated the findings of this assessment, and it can be safely concluded that the assertions made by PANKOW and his co-workers were incorrect. However, this assessment also showed that there is significant merit in the application of PANKOW's theory of absorptive partitioning for the estimation of the gas/particle partitioning of semivolatile components in MSS and ETS. Application of PANKOW's theory along with data from recent tobacco related conferences has allowed estimation of the gas/particle partition coefficient for nicotine in cigarette MSS and also has allowed approximation of values for the activity coefficient of nicotine in mainstream particulate matter.

Analytical methods based on the polymerase chain reaction (PCR) technology are increasingly used for the detection of deoxyribonucleic acid (DNA) sequences associated with genetically modified organisms (GMOs). In the European Union and Switzerland, mandatory labeling of novel foods and food ingredients consisting of, or containing GMOs is required according to food regulations and is triggered by the presence of newly introduced foreign DNA sequences, or newly expressed proteins. In order to meet regulatory and consumer demand, numerous PCR-based methods have been developed which can detect, identify and quantify GMOs in agricultural crops, food and feed. Moreover, the determination of genetic identity allows for segregation and traceability (identity preservation) throughout the supply chain of GM crops that have been enhanced with value-added quality traits. Prerequisites for GMO detection include a minimum amount of the target gene and prior knowledge of the type of genetic modification, such as virus or insect resistance traits, including controlling elements (promoters and terminators). Moreover, DNA extraction and purification is a critical step for the preparation of PCR-quality samples, particularly for processed agricultural crops such as tobacco. This paper reviews the state-of-the-art of PCR-based method development for the qualitative and quantitative determination and identification of GMOs, and includes a short summary of official and validated GMO detection methods.

Bacillus is a predominant genus of bacteria isolated from tobacco. The Gram stain is the most commonly used and most important of all diagnostic staining techniques in microbiology. In order to help confirm the Gram positivity of Bacillus isolates from tobacco, three methods using the chemical differences of the cell wall and membrane of Gram-positive and Gram-negative bacteria were investigated: the KOH (potassium hydroxide), the LANA (L-alanine-4-nitroanilide), and the vancomycin susceptibility tests. When colonies of Gram-negative bacteria are treated with 3% KOH solution, a slimy suspension is produced, probably due to destruction of the cell wall and liberation of deoxyribonucleic acid (DNA). Gram-positive cell walls resist KOH treatment. The LANA test reveals the presence of a cell wall aminopeptidase that hydrolyzes the L-alanine-4-nitroanilide in Gram-negative bacteria. This enzyme is absent in Gram-positive bacteria. Vancomycin is a glycopeptide antibiotic inhibiting the cell wall peptido-glycan synthesis of Gram-positive microorganisms. Absence of lysis with KOH, absence of hydrolysis of LANA, and susceptibility to vancomycin were used with the Gram reaction to confirm the Gram positivity of various Bacillus species isolated from tobacco. B. laevolacticus excepted, all Bacillus species tested showed negative reactions to KOH and LANA tests, and all species were susceptible to vancomycin (5 and 30 µg).

A brief review is presented of the scientific literature on the effects of ammonia compounds, when used as tobacco additives, on the smoke chemistry and bioavailablity of nicotine. The review concludes that ammonia compounds used in the manufacture of certain types of tobacco sheet materials:

1) contribute to the flavor properties of cigarette smoke,

2) do not increase the amount, rate or efficiency of nicotine transferred from tobacco to mainstream smoke (MS),

3) do not increase the percentage of nicotine in MS gas phase using the FTC/ISO (Federal Trade Commission/International Organization for Standardization) method,

4) have no influence on the determination of MS nicotine yield as measured by the FTC/ISO method, and

5) do not increase the total rate or amount of nicotine absorbed by the smoker.

The review also examines the use of pH as it relates to tobacco and to smoke and suggests a terminology which more accurately describes the measurement (pH of aqueous extract of tobacco, pH of aqueous extract of smoke, and pH/electrode in smoke). Lastly, a number of research gaps in these areas are identified.