Bronchial

Nacconate 100 A lachrymatory liquid b.p. 25l°C. Manufactured from phosgene and 2,4-diaminotoJuene. Used for preparing polyurethane foams and other elastomers by reaction with polyhydroxy compounds. Produces skin irritation and causes allergic eczema and bronchial asthma. 

Gua/aco/ is obtained by chemical treatment of lignum vitae the wood from a species of tree that grows in warm climates It is some times used as an expectorant to help relieve bronchial congestion... 

Physiological responses to prostaglandins encompass a variety of effects Some prostaglandins relax bronchial muscle others contract it Some stimulate uterine con tractions and have been used to induce therapeutic abortions PGEj dilates blood vessels and lowers blood pressure it inhibits the aggregation of platelets and offers promise as a drug to reduce the formation of blood clots... 

Most of the drugs such as epinephrine and albuterol used to treat asthma attacks are bronchodilators—substances that expand the bronchial passages Newer drugs are designed to either inhibit the enzyme 5 lipoxygenase which acts on arachidomc acid m the first stage of leukotriene biosynthesis or to block leukotriene receptors... 

Health and Safety Factors. The following toxicides for acetonitrile have been reported oral LD q (lats), 3030—6500 mg/kg skin LD q (rabbits), 3884—7850 mg/kg and inhalation LC q (i ts), 7500—17,000 ppm (29). Humans can detect the odor of acetonitrile at 40 ppm. Exposure for 4 h at up to 80 ppm has not produced adverse effects. However, exposure for 4 h at 160 ppm results in reddening of the face and some temporary bronchial tightness. 

The use of metered-dose valves in aerosol medical appHcations permits an exact dosage of an active dmg to be deHvered to the respiratory system where it can act locally or be systemicaHy absorbed. For example, inhalers prescribed for asthmatics produce a fine mist that can penetrate into the bronchial tubes (see Antiasthmatic agents). 

In additional EPA studies, subchronic inhalation was evaluated ia the rat for 4 and 13 weeks, respectively, and no adverse effects other than nasal irritation were noted. In the above-mentioned NTP chronic toxicity study ia mice, no chronic toxic effects other than those resulting from bronchial irritation were noted. There was no treatment-related increase ia tumors ia male mice, but female mice had a slight increase in bronchial tumors. Neither species had an increase in cancer. Naphthalene showed no biological activity in other chemical carcinogen tests, indicating Htde cancer risk (44). No incidents of chronic effects have been reported as a result of industrial exposure to naphthalene (28,41). 

Asthma is an extremely complex condition characterized by variable and reversible airways obstmction combiaed with nonspecific bronchial hypersensitivity (1 3). The cause of asthma, which is not always readily diagnosed (4), remains unknown. Days, if not weeks, ate needed to document the spontaneous reversal of the airways obstmction ia some patients. Asthmatics experience both an immediate hypersensitivity response and a delayed late-phase reaction, each mediated by a different pathway. Chronic asthma has come to be viewed as an inflammatory disease (5). The late-phase reaction plays a key role ia iaduciag and maintaining the inflammatory state which ia turn is thought to iaduce the bronchial hyperresponsiveness (6). The airways obstmction results from both contraction of airways smooth muscle and excessive bronchial edema. Edema, a characteristic of inflammatory states, is accompanied, ia this case, by the formation of a viscous mucus which can completely block the small airways. 

Asthma affects 3—5% of the population and is one of the most common chronic illnesses (7—9). Both the frequency and severity of asthma appear to be increasing (10—13). Acute, severe asthma has the potential to be fatal. The disease may first appear ia childhood and iadividuals so affected can suffer recurrent episodes throughout their Hves or they may "outgrow" the condition at puberty. On the other hand, there is also adult-onset asthma. These people show no symptoms as children or as young adults, but suddenly develop symptoms later ia life. There have been many reports of bronchial infections preceding the appearance of asthma. However it is not known whether these infections contributed to the development of the disease or whether iadividuals who are already predisposed to asthma ate more likely to experience bronchospasms as a result of a bronchial infection (14). 

Theophylline s predominant mode of action appears to be bronchocHlation. However, it has also been shown that prophylactic acHriinistration of theophylline provides some protection from asthma attacks and suppresses the late-phase response (67,68). Some researchers beHeve that at therapeutic semm concentrations theophylline may inhibit the development of airway inflammation (69). There are conflicting reports on the effect of theophylline on allergen-induced bronchial hyperresponsiveness some clinical stucHes report a reduction in hyper-responsiveness, others do not (69,70). Theophylline clearly does not reverse the general bronchial hyperresponsiveness over the course of long-term therapy (71). Because of the relationship between... 

Although the mechanism of glucocorticosteriod action in bronchial asthma is not fully understood, various possibiUties have been discussed in... 

Single dose or short-term treatment with aerosolized steroids inhibits both the late asthmatic response and allergen-induced bronchial hyperresponsiveness (45,92). However it does not affect the early asthmatic response nor does it induce bronchodilation (45,92). Long-term treatment with steroids protects against both the early and late asthmatic responses and also reduces bronchial hyperresponsiveness (44,71,86,93). Over time, the airways relax (dilate) and measures of airway function, such as forced expiratory volume in one second (FEV ), gradually return to almost normal levels. 

Health and Safety Factors. Sulfuryl chloride is both corrosive to the skin and toxic upon inhalation. The TLV suggested by the manufacturer is 1 ppm. The vapors irritate the eyes and upper respiratory tract, causing prompt symptoms ranging from coughing to extreme bronchial irritation and pulmonary edema. The DOT label is Corrosive, Poison. 

Soluble Compounds. The mechanism of barium toxicity is related to its ability to substitute for calcium in muscle contraction. Toxicity results from stimulation of smooth muscles of the gastrointestinal tract, the cardiac muscle, and the voluntary muscles, resulting in paralysis (47). Skeletal, arterial, intestinal, and bronchial muscle all seem to be affected by barium. 

The precise mechanism of nitrate action is not cleady understood and may be a combination of many factors. The basic pharmacologic action of nitrates is a relaxation of most vascular smooth muscle, eg, vascular, bronchial, gastrointestinal, uretal, uterine, etc. Vascular smooth muscle relaxation is a... 

Acetyl-P-methylcholine chloride [62-51-1/, commonly called methacholine chloride, is a parasympathornimetic bronchoconstrictor with clinical efficacy in bronchial asthma (45,46). 

Expectorants enhance the production of respiratory tract fluid and thus faciUtate the mobilisation and discharge of bronchial secretions. Historically, expectorants have been divided iato two classes based on specific mechanisms of action. Stimulant expectorants iacrease respiratory tract secretion by a direct effect on the bronchial secretory cells. Sedative expectorants act by gastric reflex stimulation. Many compounds classed as expectorants have been iaadequately studied and the mechanisms of action are not known with certainty. 

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