Irritation of tissues

The medication is a sterile water extract from autotrophic bacteria Ferrooxidans spp. culture medium. It is a reddish liquid with acidic reaction (pH 3.0) and astringent action. The preparation does not cause irritation of tissues and is intended for external use. However, at present the possibility of its oral administration is being studied. 

Dilute acetic acid in the form of vinegar is harmless and has been consumed by humans for centuries. Prolonged contact with the skin or eyes may, however, produce irritation of tissues and should be avoided. Concentrated forms of acetic acid pose more serious health risks, such as irritation of the gastrointestinal system, respiratory system, and eyes. Most people do not come into contact with the concentrated acid, and safety precautions are of importance only to individuals who handle the material in their work. 

ACUTE HEALTH RISKS irritation of eyes, skin, and respiratory tract irritation of tissues of mucous membranes conjunctiva irritation headache dizziness shortness of breath cough sore throat dullness narcosis abdominal cramps lowering of consciousness coma. 

Acetic anhydride can cause irritation of tissue, especially in nasal passages. Avoid breathing the vapor, and avoid contact with skin and eyes. p-Aminophenol is a skin irritant and is toxic. 

Health and Safety Factors. Unlike fluoroacetic acid, trifluoroacetic acid presents no unusual toxicity problems. However, owing to its strong acidity, its vapors can be irritating to tissue, and the Hquid acid can cause deep bums if allowed to contact the skin. The acid can be safely stored in containers made of glass or common corrosion-resistant alloys and metals such as stainless steel or alurninum. 

Hexachlorocyclotriphosphazene (cycHc trimer) is a respiratory irritant. Nausea has also been noted on exposure (10). Intravenous and intraperitoneal toxicity measurements were made on mice. The highest nonlethal dose (LDq) was measured as 20 mg/kg (11). Linear chloropolymer is also beUeved to be toxic (10). Upon organic substitution, the high molecular weight linear polymers have been shown to be inert. Rat implants of eight different polyphosphazene homopolymers indicated low levels of tissue toxicity (12). EZ has been found to be reasonably compatible with blood (13), and has lower hpid absorption than fiuorosihcone. 

Watts (1979), while agreeing that bacterial contamination plays an important role in causing irritation to tissues, showed that a silicate cement even under germ-free conditions produced tissue damage. Of course, the acidic dental silicate cement does not possess the antiseptic action of the alkaline cements. 

Intravenous medication is injected directly into a vein either to obtain an extremely rapid and predictable response or to avoid irritation of other tissues. This route of administration also provides maximum availability and assurance in delivering the drug to the site of action. However, a major danger of this route of administration is that the rapidity of absorption makes effective administration of an antidote very difficult, if not impossible, in most instances. Care must often be... 

An ophthalmic suspension should use the drug in a microfine form usually 95% or more of the particles have a diameter of 10 pm or less. This is to ensure that the particles do not cause irritation of the sensitive ocular tissues and that a uniform dosage is delivered to the eye. Since a suspension is made up of solid particles, it is at least theoretically possible that they may provide a reservoir in the cul-de-sac for slightly prolonged activity. However, it appears that this is not so, since the drug particles are extremely small, and with the rapid tear turnover rate they are washed out of the eye relatively quickly. 

Acute-Duration Exposure. Information is available regarding the effects of acute-duration inhalation exposure of humans to acrylonitrile and the effects are characteristic of cyanide-type toxicity. Quantitative data are limited but are sufficient to derive an acute inhalation MRL. Further studies of humans exposed to low levels of acrylonitrile in the workplace would increase the confidence of the acute MRL. Studies in animals support and confirm these findings. No studies are available on the effects of acute-duration oral exposure in humans however, exposure to acrylonitrile reveals neurological disturbances characteristic of cyanide-type toxicity and lethal effects in rats and mice. Rats also develop birth defects. Animal data are sufficient to derive an acute oral MRL. Additional studies employing other species and various dose levels would be useful in confirming target tissues and determining thresholds for these effects. In humans, acrylonitrile causes irritation of the skin and eyes. No data are available on acute dermal exposures in animals. 

Fig. 2. Pathophysiological sequence of events in periodontal disease. Bacteria produce byproducts (e.g. toxins or enzymes) which, along with mucus, constantly form a sticky, colorless plaque on teeth. If not removed, plaque can harden and form bacteria-harboring tartar around teeth. Tissue that attaches the gums to the teeth can be destroyed by the irritants of plaque. If this is the case, gums pull away from the teeth and small pockets arise between the teeth and gums. The pockets then become filled with more plaque, deepen, and it becomes impossible to clean plaque out. At this stage the bone structure supporting teeth can actually be destroyed (courtesy of Drs J. Chavez and S.E. Zaragoza, El Paso Community College, Texas, USA).

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