Types of Irritations

Main groups of microorganisms are bacteria, gram-positive bacteria and gram-negative bacteria, fungi, and yeasts. 

The t) e of action of various microorganisms on plastics is shown in Table 6.1. The action of various microorganisms on human health is shown in Table 6.2. 

Antimicrobial additives are added to polymers in order to protect the material against the negative impact arising from microorganisms. 

Plasticized poly(vinyl chloride) (PVC), poly(urethane)s, poly(eth-ylene) (PE), and poly(ester)s are particularly sensitive to microbial attack. Flexible PVC is by far the main plastic in which biostabilizers are incorporated, followed by poly(urethane) foams, and other resins. PVC itself is resistant to microbial attack, however, plasticizers, fillers, pigments, lubricants, and other additives used in PVC are 

All of the Proteus strains form dxuring their metabolism the enzyme urease, which has the ability to rapidly break down urea into ammonia (6). 

---

Direct irritation may thus be dehned as an adverse effect of chemicals directly applied to the skin that does not involve prior sensitization and thus initiation by an immune mechanism. Irritation is usually assessed by a local inflammatory response characterized by erythema (redness) and/or edema (swelling). Other responses may be present that do not elicit inflammation such as an increase in skin thickness. Irritant reactions may be classified as acute, cumulative, traumatic, or pustular. However, two classifications are generally used by toxicologists. Acute irritation is a local response of the skin usually caused by a single agent that induces a reversible inflammatory response. Cumulative irritation occurs after repeated exposures to the same compound and is the most common type of irritant dermatitis. 

There are several types of irritancy testing protocols that are used to comply with federal and international safety regulations. The classic Draize test was developed in 1944 to measure acute primary irritation. The test compound is applied in an occluded fashion to a clipped area of abraded and intact skin of at least six albino rabbits and evaluated 24 hr and 72 hr after patch removal. The degree of erythema and edema, ranging from one to four, is recorded to reflect severity of the irritation. Because these tests are occluded, irritancy is potentiated due to hydration, which reduces the skin barrier. The Draize test may be modified to assess sensitization by preexposing animals to a sensitizing dose of the study chemical and then rechallenging the animals at a later date to illicit the immune-mediated response. 

A sternutator type of irritant chemical agent that can be disseminated in the air as extremely small solid or liquid particles. 

Testing is performed to evaluate the potential occurrence of two different, yet related, endpoints, irritation and sensitization. The broadest application of these is evaluation of the potential to cause skin irritation, characterized by erythema (redness) and edema (swelling). Severity of irritation is measured in terms of both the degree of these two parameters and how long they persist. Primary irritation, cutaneous sensitization, phototoxicity, and photosensitization are possible types of dermal irritation resulting from dermal application. There are three types of irritation tests, each designed to address a different concern ... 

Irritants produce a wide range of clinical features. Cutaneous responses depend on the type of irritant (Table 2), the concentration at which the irritant comes into contact with the skin, the type of exposure, and the individual response. Clinical manifestations of ICD syndromes are also modified by external factors, such as environmental factors (mechanical pressure, temperature, and humidity) and predisposing characteristics of the individual (age, gender, ethnic origin, pre-existing skin disease, atopic skin diathesis and the anatomic region exposed) (Pinnagoda et al. 1989 Emtestam and OUmar 1993). 

Cumulative irritation is one of several types of Irritant contact dermatitis is often localized to the irritant contact dermatitis. Each type has a char- exposed sites first, and then can spread to other... 

I Type of Irritation II Onset II Prognosis II Example irritants... 

CAUSES OF HEARTBURN. Although the pain experienced in heartburn is sometimes due to a peptic ulcer, in many cases there is some type of irritation or spasm of the esophagus. Two of the most common esophageal disorders are Esophageal Reflux and Hiatus Hernia. 

Esophageal reflux (esophagitis)— This type of irritation, also known as esophagitis, results from regurgitation of stomach acid into the esophagus. 

Acrylic polymers are considered to be nontoxic. In fact, the FDA allows certain acrylate polymers to be used in the packaging and handling of food. However, care must be exercised because additives or residual monomers present in various types of polymers can display toxicity. For example, some acryflc latex dispersions can be mild skin or eye irritants. This toxicity is usually ascribed to the surfactants in the latex and not to the polymer itself. 

Boron trifluoride [7637-07-2] (trifluoroborane), BF, was first reported in 1809 by Gay-Lussac and Thenard (1) who prepared it by the reaction of boric acid and fluorspar at duU red heat. It is a colorless gas when dry, but fumes in the presence of moisture yielding a dense white smoke of irritating, pungent odor. It is widely used as an acid catalyst (2) for many types of organic reactions, especially for the production of polymer and petroleum (qv) products. The gas was first produced commercially in 1936 by the Harshaw Chemical Co. (see also Boron COMPOUNDS). 

Skin and Eye Irritation. Fatty alkylamines are generally considered to be irritating to both the skin and eyes (83). The severity or degree of irritation is usually dependent on the type of alkylamine, concentration of the chemical, time of exposure to the chemical, and sensitivity to the chemical. A small percentage of the population who come into contact with fatty amines may develop a skin hypersensitivity to certain amines and diamines. 

Soap as used in personal cleansing products has a long safe history of use. Modem soaps have been specifically formulated to be compatible with skin and to be used on a daily basis with minimal side effects. Excessive use of soap for skin cleansing can dismpt the natural barrier function of skin through the removal of skin oils and dismption of the Hpid bdayer in skin. This can result in imperfect desquamation or a dry appearance to skin and cause an irritation response or erythema, ie, reddening of the skin. Neither of these is a permanent response and the eHcitation of this type of skin reaction depends on the individual s skin type, the product formulation, and the frequency of use. 

The so-called El-emission class describes a wood panel presenting formaldehyde emission which is low enough to prevent any danger, irritation or inflammation of the eyes, nose and mouth mucous membranes. However, it is important that not only the boards themselves, but also the veneering and carpenter s adhesive resins, laquers, varnishes and other sources of formaldehyde are under control, since they also might contribute to the mixture steady state formaldehyde concentration [9]. Table 3 gives an overview on some European regulations. However, it is necessary here to introduce the principal types of composite wood products, especially panels, that are produced in this industry ... 

Halothane (Fluothane) is a volatile liquid given by inhalation for induction and maintenance of anesthesia Induction and recovery from anesthesia are rapid, and the depth of anesthesia can be rapidly altered. Halothane does not irritate the respiratory tract, and an increase in tracheobronchial secretions usually does not occur. Halothane produces moderate muscle relaxation, but skeletal muscle relaxants may be used in certain types of surgeries. This anesthetic may be given with a mixture of nitrous oxide and oxygen. 

Comparative primary skin irritation scores of surfactant solutions (15% active content) show various types of sulfosuccinates as being the least irritant materials, well below sodium laureth-3 sulfate. It was also shown that an increase in degree of ethoxylation reduces skin and eye irritation, leading to laureth-3 (lauryl alcohol with 3 mol ethylene oxide) as the ideal organic raw material [17]. The results are given in Fig. 9 for eye irritation and in Fig. 10 for skin irritation. 

Furthermore, we found that the two types of tumor promoters induced common biological effects, such as irritation of mouse ear, and stimulation of prostaglandin E2 production and of arachidonic acid metabolism in rat macrophages. These common effects seem to be the most essential biological activities in tumor promotion (6). 

---