Chronic prolonged effects

Vanadium compounds, including those which may be involved in the production, processing, and use of vanadium and vanadium alloys, are irritants chiefly to the conjuctivae and respiratory tract. Prolonged exposure may lead to pulmonary compHcations. However, responses are acute, never chronic. Toxic effects vary with the vanadium compound involved. For example, LD q (oral) of vanadium pentoxide dust in rats is 23 mg/kg of body weight (24). 

Because AEDs are administered for long periods of time, adverse effects due to prolonged drug exposure are of concern. Some chronic adverse effects that have been associated with AEDs include peripheral neuropathy and cerebellar atrophy Other chronic adverse effects are extensions of acute adverse effects, for example weight gain. 

In contrast to the documented effect of cotton dust on acute responses, the causation of chronic respiratory effects in occupationally exposed subjects has not been established. The OSHA cotton dust standard is based on the premise that sustained exposure may result in chronic respiratory problems. To test this hypothesis, the pertinent literature is reviewed and discussed in an attempt to decide if convincing epidemiological documentation exists to support a cause and effect connection between prolonged dust exposure and chronic respiratory impairment. There appears to be a need for additional studies to clarify this important aspect of occupational medicine. 

With the promulgation of the OSHA mandatory standards for exposure to cotton dust ( ), it is now assumed that prolonged exposure to cotton dust is a cause of chronic respiratory effects. Thus, there seems to have been a straightforward interpretation of complex and conflicting medical literature. This paper presents a review of the literature with emphasis on cause and effect relationship consistent with reported epidemiological data. 

A low pretreatment platelet count, the dose of interferon alfa, and the haptoglobin phenotype are risk factors for ribavirin-induced anemia, and the fall in hemoglobin is independent of dose in the therapeutic range (16). In five patients with chronic hepatitis C on hemodialysis who received subcutaneous interferon alfa-2b and oral ribavirin for 40 weeks, the dose of ribavirin was titrated based on hemoglobin, with bone marrow support by erythropoietin (17). There was significant bone marrow toxicity in all five. A dose of 200 mg/day produced a steady-state AUC comparable to that obtained with 1000-1200 mg/ day in historical controls with normal renal fnnction. More severe anemia was possibly due to chronic renal insufficiency in addition to the prolonged effects of ribavirin. 

M4. Mackay, I. R., Chronic hepatitis. Effect of prolonged suppressive treatment and comparison of azathioprine with prednisolone. Quart. J. Med. [N. S.] 37, 379-392 (1968). 

CHRONIC HEALTH RISKS a rubber solvent induced chromosomal aberrations in human whole-blood cultures repeated exposure can damage the nervous system, including headache, fatigue, poor concentration, emotional instability, impaired memory and other intellectual functions chronic neruotoxic effects include motor polyneuropathy prolonged contact can cause drying and cracking of skin. 

CHRONIC HEALTH RISKS no chronic systemic effects have been reported in humans can cause dermatitis on prolonged exposure however, persons with pre-existing skin disorders may be more susceptible to its effects may cause exacerbation of symptoms in persons with impaired pulmonary function. 

In addition to acute lung effects and chronic renal effects, long term exposure to cadmium may cause other severe effects on the respiratory system. Reduced pulmonary function and chronic lung disease indicative of emphysema have been observed in workers who have had prolonged exposure to cadmium dust or fumes (Exs. 4-29, 4-22, 4-42, 4-50, 4-63). In a Study of workers conducted by Kazantzis et a ., a statistically significant excess of worker deaths due to chronic bronchitis was found, which in his opinion was directly related to high cadmium exposures of 1 mg/m or more (Tr. 6/8/90, pp. 156-157). 

The external dose to the critical population group in conditions of chronic (prolonged) exposure should be determined on the basis of environmental monitoring data by the use of a simple calculation model in which account is taken of the partial shielding of the human environment in comparison with an open area, human occupation, the ratio between the dose in air and the effective dose, and the seasonal variation of relevant parameters. 

In conditions of chronic (prolonged) exposure, there is usually no danger of deterministic health effects among the population, and therefore methods of dose assessment based on best parameter estimates should be employed, rather than conservative models as used in emergencies. 

Chronic effects develop over a period of time which may extend to many years. The word chronic means with time and should not be confused with severe as its use in everyday speech often implies. Chronic health effects are produced from prolonged or repeated exposures to hazardous substances resulting in a gradual, latent and often irreversible illness, which may remain undiagnosed... 

When dispersed as a dust, adipic acid is subject to normal dust explosion hazards. See Table 3 for ignition properties of such dust—air mixtures. The material is an irritant, especially upon contact with the mucous membranes. Thus protective goggles or face shields should be worn when handling the material. Prolonged contact with the skin should also be avoided. Eye wash fountains, showers, and washing faciUties should be provided in work areas. However, MSDS Sheet400 (5) reports that no acute or chronic effects have been observed. 

Health and Safety Factors. Boron trifluoride is primarily a pulmonary irritant. The toxicity of the gas to humans has not been reported (58), but laboratory tests on animals gave results ranging from an increased pneumonitis to death. The TLV is 1 ppm (59,60). Inhalation toxicity studies in rats have shown that exposure to BF at 17 mg/m resulted in renal toxicity, whereas exposure at 6 mg/m did not result in a toxic response (61). Prolonged inhalation produced dental fluorosis (62). High concentrations bum the skin similarly to acids such as HBF and, if the skin is subject to prolonged exposure, the treatment should be the same as for fluoride exposure and hypocalcemia. No chronic effects have been observed in workers exposed to small quantities of the gas at frequent intervals over a period of years. 

Undiluted DMAMP, AMP-95, and AB cause eye bums and permanent damage, if not washed out immediately. They are also severely irritating to the skin, causing bums by prolonged or repeated contact. Of these three aLkanolarnines, only AMP has been studied in subchronic and chronic oral studies. The principal effect noted was the action of AMP on the stomach as a result of its alkalinity. The no-observed-effect level (NOEL) in a one-year feeding study in dogs was 110 ppm in the diet. In general, the low volatility and appHcations for which these products are used preclude the likelihood of exposure by inhalation. 

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