Brain tumors Secondhand smoke causes other diseases and death Secondhand smoke can be harmful in many ways. For instance, it affects the heart and blood vessels, increasing the risk of heart attack and stroke in non-smokers. Some studies have linked SHS to mental and emotional changes, too.
The first is through the application of cigarette-smoke condensates to skin. Cigarette-smoke condensates are collected by passing smoke through cold traps and recovering the retained material. The cigarettes are usually machine-smoked and the material is washed from the traps using a volatile substance Environmental tobacco smoke as acetone, which is then removed.
Many of the procedures for collecting this cigarette-smoke-condensate have not yet been standardized across laboratories, including how the condensate is stored, in what numbers and fashion the cigarettes are smoked, and the type of solvent used.
Once the condensate is collected, it is painted onto the skin of the animal test subjects, which are then examined at set intervals to assess the growth of tumors.
The second method, as described by the IARC monographs, used to measure the carcinogenicity of cigarette smoke to animals is by exposing them to mainstream cigarette smoke.
The IARC monographs define mainstream cigarette smoke as that which is emitted by the mouth end of the cigarette and therefore the smoke Environmental tobacco smoke human smokers would be exposed to most. The IARC monographs describe the methods and equipment that scientists have developed to make more effective and standardize the deliverance of mainstream cigarette smoke.
These devices vary between whole-body and nose-only exposure, but typically involve machine smoked cigarette smoke being pumped into a small chamber that contains the animal test subjects.
A variety of factors differentiate the experience of a human smoker from these animal test subjects'. Human smokers inhale smoke voluntarily and therefore do so more deeply than do animal test subjects which typically adopt short, shallow breaths when exposed to smoke.
The animal test subjects, primarily rodents and dogs, also have significantly morphologically different upper respiratory system from humans. Despite these variables, the doses of smoke administered to these animals can be determined by examining tissue and blood samples.
Dogs, which cannot be exposed to cigarette smoke via inhalation chambers as easily as can small rodents, require different methods of cigarette smoke exposure. These methods include thracheostomy, in which smoke is pumped through a tube directly into a hole cut in the dog's throat, or through a mask fitted to the dog's face.
Although the carcinogenicity of tobacco smoke was first established in humans, various types of animals have also been exposed to tobacco smoke inhalation in attempts to yield further experimental proof and control for various experimental factors, including types of tobacco and levels of exposure, which would be considered unethical in human studies.
The IARC monographs, referencing studies which used various methods of smoke inhalation, concluded that a significantly greater number of pulmonary tumors occurred among mice exposed to smoke than those in the control groups.
Since the s, the animal most used in testing the carcinogenicity of tobacco smoke has been the Syrian Golden Hamster due to its resistance to pulmonary infections and the infrequency with which it spontaneously develops pulmonary tumors.
Some studies referenced in the IARC monographs found that certain, but not all, groups of rats exposed to mainstream smoke were significantly more likely to develop lung tumors. The IARC monographs also referenced studies involving rabbits and dogs that were much less conclusive.
The authors, however, cited various experimental limitations, such as small test or control groups and missing data, that could account for the lack of conclusive results. These studies typically fall under the categories of simulated environmental tobacco, administering condensates of sidestream smokeor observational studies of cancer among pets.
Simulated environmental tobacco smoke[ edit ] To study the consequences of passive smoking, scientists expose animals to sidestream smoke, that which emanates from the cigarette's burning cone and through its paper, or a combination of mainstream and sidestream smoke.
Condensates of sidestream smoke[ edit ] The IARC monographs concluded that sidestream smoke condensates had a significantly higher carcinogenic effect upon mice than did mainstream smoke condensates. The number of smokers within the home, the number of packs smoked in the home per day, and the amount of time that the dog spent within the home had no effect on the dog's risk for lung cancer.
The proposed study was blocked by Philip Morris as described in an internal company report: PM [Philip Morris] recently succeeded in blocking Adlkofer's plan to conduct lifetime animal inhalation study of sidestream smoke.
In a lifetime study, the results were almost certain to be less favorable. Based on the analysis, the other members of the German industry agreed that the proposed study should not proceed.Secondhand smoke (SHS) is also called environmental tobacco smoke (ETS).
It’s a mixture of 2 forms of smoke that come from burning tobacco: Mainstream smoke: The smoke exhaled by a smoker. Sidestream smoke: Smoke from the lighted end of a cigarette, pipe, or cigar, or tobacco burning in a .
The 45 children exposed to environmental tobacco smoke had an average of episodes of middle ear effusion between 6 and 24 months of age, whereas the 87 children unexposed to environmental tobacco smoke had episodes during that period. Second-hand tobacco smoke. Involuntary (or passive) smoking is the exposure to second-hand tobacco smoke (SHS) which is a mixture of exhaled mainstream smoke and side stream smoke released from a smouldering cigarette or other smoking device (cigar, pipe, bidi, .
Smoke-Free Policies in Facilities Serving Older Persons. The Center for Social Gerontology Shelby Avenue, Ann Arbor, MI tel: fax: Animals are exposed to tobacco smoke and other cigarette by-products through their use as experimental subjects and through contact with smokers, as in . The IEQ Unit provides consultation, technical assistance, education, and trainin g to local health departments, housing code enforcement officials, other state agencies, health care providers, and the public regarding environmental conditions in homes, schools and workplaces that can lead to poor IEQ and impact health..