Respiratory tract, penetration

The sites of action and effects of ozone and other photochemical oxidants are described in Chapters 8 and 9. Recent work with primates has suggested that ozone is absorbed along the entire respiratory tract, penetrates more into the peripheral nonciliated airways, and causes more lesions in the respiratory bronchioles and alveolar ducts as the inhaled ozone concentration increases from 0.2 to 0.8 ppm. The most common and most severe tissue damage was observed in the respiratory bronchioles. The ciliated cells in the terminal bronchioles and the Type 1 cells in the epithelial layer of the proximal alveoli of rats were the... 

Chlorine gas is a respiratory irritant and is readily detectable at concentrations of <1 ppm in air because of its penetrating odor. Chlorine gas, after several hours of exposure, causes mild irritation of the eyes and of the mucous membrane of the respiratory tract. At high concentrations and in extreme situations, increased difficulty in breathing can result in death through suffocation. The physiological response to various levels of chlorine gas is given in Table 19. 

Tlie respiratory system is tlie main target organ for vapour, gas or mist. Readily-soluble cheirticals, e.g. chlorine or phosgene, attack the upper respiratory tract less soluble gases, e.g. oxides of nitrogen, penetrate more deeply into the conducting airways and, in some cases, may cause pulmonary oedema, often after a time delay. 

Studies on the particulate distributions from compressed natural gas (CNG) or diesel-fuelled engines with diesel oxidation catalyst (DOC) or partial diesel particle filter (pDPF) have also been performed. The results obtained are used as data for the model, to study the particle penetration into the human respiratory tracts. As a result, the number distribution of particles in different parts of lungs can be modeled [99-101]. Understanding the particle formation and their effects and finding the methods to ehminate the formed particulates from exhaust gas contribute to a cleaner urban environment and thus to a better quality of life. 

Pulmonary dynamics, the dimension and geometry of the respiratory tract and the structure of the lungs, together with the solubility and chemical reactivity of the inhalants greatly influence the magnitude of penetration, retention, and absorption of inhaled gases, vapors (Dahl, 1990), and aerosols (Raabe, 1982 Phalen, 1984). The quantity of an inhalant effectively retained in the pulmonary system constitutes the inhaled dose that causes pharmacotoxic responses. 

In general, slow, deep inhalation followed by a period of breath holding increases the deposition of aerosols in the peripheral parts of the lungs, whereas rapid inhalation increases the deposition in the oropharynx and in the large central airways. Thus, the frequency of respiration (the flow velocity) and the depth of breath (tidal volume) influence the pattern of pulmonary penetration and deposition of inhaled aerosols. Therefore, an aerosol of ideal size will penetrate deeply into the respiratory tract and the lungs only when the aerosols are inhaled in the correct manner (Sackner, 1978 and Sackner et al., 1975). 

Even less is known about the effects of ozone on carbohydrates. Buell et al. observed a decrease in the depolymerization of hyaluronic acid after treatment of the lungs of ozone-exposed rabbits (1 ppm for 1 h) with hyaluronidase. B. Goldstein et al. reported a loss in membrane neuraminic acid of red cells exposed in vitro to high concentrations of ozone. It would be important to study the effects of ozone on respiratory tract mucus, which is rich in carbohydrates, including neuraminic acid. This could indude determination of foe extent to which ozone is able to penetrate mucus that is unaltered, whether foe reaction of ozone with mucus results in the formation of cytotoxic intermediates, and evaluation of the interaction in mucus of ozone with other air pollutants, particularly sulfur dioxide. Of possible pertinence is a study by Falk et who observed that ozone produced a loss in foe viral hemagglutinating ability of snail mucus. 

Aerosols must be respirable, that is, have a mean aerodynamic diameter of less than 5 xm, to ensure that a reasonable proportion will penetrate the respiratory tract defence systems of the nasal passages and the mucociliary clearance mechanisms. 

The critical factor in the development of the syndrome is the size of the ultrafine zinc oxide particles produced when zinc is heated to temperatures approaching its boiling point in an oxidizing atmosphere." The particles must be small enough (zinc oxide powder is either inhaled or taken orally. Only freshly formed fume causes the illness, presumably because flocculation occurs in the air with formation of larger particles that are deposited in the upper respiratory tract and do not penetrate deeply into the lungs. ... 

If spilled on the skin or in the eyes liquid N2IL, can cause severe local damage or burns and can cause dermatitis. In addition it can penetrate skin to cause systemic effects similar to those produced when the compound is swallowed or inhaled. Inhalation of the vapor causes local irritation of the respiratory tract and eyes. On short exposure systemic effects involve the central nervous system. Resultant symptoms include tremors, on exposure to higher concentrations, convulsions and possibly death follow. Repeated exposures may cause toxic damage to the liver (fatty liver) and kidney (interstitial nephritis), as well as anemia. The threshold limit value of hydrazine is 1 ppm (1.3 mg/m3)(Ref 20) (See also Refs 27 c and 33a)... 

From the environmental point of view, the three principal routes of entry of xenobiot-ics into the human body are percutaneous, respiratory, and oral. In multicellular animals, the extracellular space is filled with interstitial fluid. Thus, regardless of how a compound enters the body (with the exception of intravenous administration), it enters interstitial fluid after penetrating the initial cellular barrier (such as skin, intestinal mucosa, or the lining of the respiratory tract). From the interstitial fluid, the compound penetrates the capillaries and enters the bloodstream, which distributes it throughout the body. 

Dirty Purulence or abscess preoperative perforation of respiratory, gastrointestinal, biliary, or oropharyngeal tract penetrating trauma more than 4 hours old expected infection rate about 40%. 

As mentioned above, gas has been widely used and it is a powerful vesicant agent. In the form of vapor, it damages the respiratory tract. Eyes become temporarily blind and the skin in contact with the substance becomes inflammatory. The sweaty zones of skin are the most damaged as well as sensitive mucous membranes. If no treatment is applied, the cutaneous reaction provokes blisters full of liquid after 4-8 h. Spread in the form of particles, the gas penetrates the respiratory tract and destroys the mucous membranes with a respiration distress syndrome. Lungs suffer from emphysemae and edema due to the presence of fluids, which may cause a death similar to a drowning if the dose is too strong. 

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