Respiratory tract/system lower

Phenols are carcinogenic [39-42] and mutagenic thus affect the central nervous system. Long term contact to phenol may even paralyze the body and damage liver, kidneys [41] and heart [43]. Phenol and its vapour are corrosive to the eyes, skin and respiratory tract [44], Renal failure and pulmonary toxicity has been reported with overdose of 89% injectable phenol solution [45]. According to Central Pollution Control Board (CPCB) the discharge limit of phenol in inland water should be lower than 1 mg/1 [46],... 

An increased incidence in mycoplasma infections in rats exposed to 260 ppm hexachloroethane for 6 weeks suggests that hexachloroethane might weaken resistance to infection (Weeks et al. 1979). This could be the result of either a change in the quantity or consistency of the respiratory tract mucus or a systemic weakening of the immune system. The data are inadequate to formulate any hypothesis regarding the mechanism for diminished host resistance or to postulate whether hexachloroethane in the environment might lower the resistance of humans to respiratory infections. 

Relative to body weight, humans have a much lower respiratory rate and cardiac output than rodents. These are the two primary determinants of systemic uptake of volatile chemicals. Therefore, at similar nominal concentrations, rodents absorb substantially more cyanide than primates. From a pharmacokinetic view, lower hepatic rhodanese levels in primates will not be significant at high, acute HCN exposures. It should be noted that Barcroft s subject withstood a 1 min and 31 s exposure at approximately 500 to 625 ppm without immediate effects (Barcroft 1931), whereas mice suffer asphyxia during a 2 min exposure at 500 ppm (Matijak-Schaper and Alarie 1982). Compared with rodents, the respiratory tracts of humans and monkeys are more similar in gross anatomy, the amount and distribution of types of respiratory epithelium, and airflow patterns (Barrow 1986 Jones et al. 1996). 

These two definitions reflect two sides of the same situation. In this book, the term critical effect(s) will be used for the hazard/effect considered as being the essential one(s) for the purpose of the risk characterization, e.g., for the establishment of a health-based guidance value, permissible exposure level, or Reference Dose. It should be noted that the critical effect could be a local as well as a systemic effect. It should also be recognized that the critical effect for the establishment of a tolerable exposure level is not necessarily the most severe effect of the chemical substance. For example, although a substance may cause a serious effect such as liver necrosis, the critical effect for the establishment of, e.g., an occupational exposure limit could be a less serious effect such as respiratory tract irritation, because the irritation occurs at a lower exposure level. 

Yellow phosphorus burns spontaneously in air, and the vapor released is irritating to the respiratory tract. The early signs of systemic intoxication by phosphorus are abdominal pain, jaundice, and a garlic odor of the breath prolonged intake may cause anemia, as well as cachexia and necrosis of bone, involving typically the maxilla and mandible (phossy jaw). In chronic phosphorus intoxication, lowered potassium blood levels or increased chloride concentrations along with leukopenia have also been reported. ... 

Theophylline and other methylxanthines also display a pharmacological effect on a number of other organ systems. Of course the most pronounced effect is relaxation of smooth musculature in the respiratory tract. However, theophylline is a CNS stimulant, and it lowers arterial blood pressure, increases diuresis, displays cardiotonic activity, and has a specific effect on the gastrointestinal tract. The effects listed are the most frequently encountered side effects upon taking theophylline as a broncholytic. 

Systemic Effects.Silver nitrate and/or silver oxide have been reported to cause upper and lower respiratory tract irritation in humans when inhaled. In one case, inhalation of an unknown amount and chemical form of silver during work with molten silver ingots produced respiratory failure the day after exposure (Forycki et al. 1983). Without treatment the worker may have died. However, exposures such as this are not expected to be common and should be examined on a case by case basis. 

The respiratory system is responsible for mediating gas exchange between the external environment and the bloodstream. The upper respiratory tract conducts air to the lower respiratory passages and ultimately to the lungs. It also humidifies and conditions inspired air and serves to protect the lungs from harmful substances. In the lungs, gas exchange takes place between the alveoli and the pulmonary circulation. 

Anatomy and physiology. The human respiratory system is divided into upper and lower respiratory tracts. The upper respiratory system consists of the nose, nasal cavities, nasopharynx, and oropharynx. The lower respiratory tract consists of the larynx, trachea, bronchi, and alveoli, which are composed of respiratory tissues. 

IFN-y, a 20 to 25 kDa lymphokine, is synthesized naturally by activated T cells, and is critical in the immune response against Mycobacterium tuberculosis. Beck et al. [94] have demonstrated the efficacy of aerosol-administered murine IFN-y in pneumocystis-infected mice, while the results of studies in rodents have indicated an antitumor effect [95] and anti-infective potential of IFN-y [96]. Deposition studies indicated that aerosolized IFN-y can be effectively delivered to the lower respiratory tract, and that IFN-y given by this route does not reach the systemic... 

Pneumonitis, noncardiogenic pulmonary edema Ocular and respiratory tract inflammation, pneumonitis central nervous system (CNS), kidney, and systemic effects Upper and lower airway injury, pneumonitis, CNS depression, seizures... 

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