Isolation toxicity

Surprisingly little research has been performed on the otic effects of chemicals on workers. However, several widely used chemicals are known to be ototoxic. However, the combination of toxin exposure and noise may be additive or synergistic in the production of hearing loss. This has made investigation of the isolated toxic effects on exposed workers difficult (Table 3). 

In summary, for uew classes of compouuds, the recommeudatiou is that either the situatiou may be ideutified (humau illuess outbreak, new species or strain of algae or new symptoms of toxicity in mouse test), toxicological evaluation of the crude toxin extracts made or, ideally, isolated toxic compound should be carried out in order to assess the risk before deciding not to regulate or set a tolerable level. 

Tetracyclines are produced by various Streptomyces strains and are extensively applied in human and veterinary medicine. They display a broad spectrum of antimicrobial activity in combination with low toxicity and can be applied orally. The most commonly prescribed tetracycline drugs are tetracycline itself and oxytetracycline, an oxygenated derivative, which are directly isolated from fermentation liquors, and doxycycline whose partial synthesis from oxy-... 

Nebulanne is a toxic nucleoside isolated from a species of mushroom Its systematic name IS 9 P D nbofuranosylpurine Write a structural formula for nebulanne... 

Lycorine (69) was recognized as a potent emetic and a moderately toxic base from the time of its initial isolation from Narcissus pseudonarcissus E. (in about 1877) (48). Since that time its isolation from many other AmaryUidaceae, for example, Lpcom radiate Herb., has served to estabUsh it as the most cosmopohtan alkaloid of the family. TypicaUy, as much as 1% of the dry weight of daffodil bulbs may consist of lycorine (69), which has been reported to... 

Because PTFE resins decompose slowly, they may be heated to a high temperature. The toxicity of the pyrolysis products warrants care where exposure of personnel is likely to occur (120). Above 230°C decomposition rates become measurable (0.0001% per hour). Small amounts of toxic perfiuoroisobutylene have been isolated at 400°C and above free fluorine has never been found. Above 690°C the decomposition products bum but do not support combustion if the heat is removed. Combustion products consist primarily of carbon dioxide, carbon tetrafluoride, and small quantities of toxic and corrosive hydrogen fluoride. The PTFE resins are nonflammable and do not propagate flame. 

Arsenic Peroxides. Arsenic peroxides have not been isolated however, elemental arsenic, and a great variety of arsenic compounds, have been found to be effective catalysts ia the epoxidation of olefins by aqueous hydrogen peroxide. Transient peroxoarsenic compounds are beheved to be iavolved ia these systems. Compounds that act as effective epoxidation catalysts iaclude arsenic trioxide, arsenic pentoxide, arsenious acid, arsenic acid, arsenic trichloride, arsenic oxychloride, triphenyl arsiae, phenylarsonic acid, and the arsenates of sodium, ammonium, and bismuth (56). To avoid having to dispose of the toxic residues of these reactions, the arsenic can be immobi1i2ed on a polystyrene resia (57). 

Gapreomycin, Viomycin, and Enviomycin. Capreomycin (Capastat, Lilly), a bacteriostatic, antimycobacterial peptide mixture isolated from Streptomjces capreolus was first reported in 1961 (106—108). This tuberactinomycin family member, shown in Table 4, was introduced into the U.S. market in 1971 where it has remained a usehil but nephrotoxic and ototoxic second-line alternative to first-line tuberculosis therapies. Because capreomycin is somewhat less toxic than viomycin (tuberoactinomycin B [32988-50-4]) C25H42N23O2Q (109,110), capreomycin has now displaced viomycin in the United States and most other markets. The stmcture of viomycin is shown in Figure 2. The related enviomycin (tuberactinomycin N [33103-22-9]), C23H43N23O2Q,... 

Other Lethal Agents. There are a number of substances, many found in nature, which are known to be more toxic than nerve agents (6). None has been weaponized. Examples of these toxic natural products include shellfish poison, isolated from toxic clams puffer fish poison, isolated from the viscera of the puffer fish the active principle of curare "heart poisons" of the digitaUs type the active principle of the sea cucumber active principles of snake venom and the protein ricin, obtained from castor beans (See Castor oil). 

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