Toxicity modification

Muggia FM, Hainsworth JD, Jeffers S, Miller P, Groshen S, Tan M, Roman L, Uziely B, Muderspach L, Garcia A, Burnett A, Greco FA, Morrow CP, Paradise LJ, Liang LJ. Phase II study of liposomal doxorubicin in refractory ovarian cancer antitumor activity and toxicity modification by liposomal encapsulation. J Clin Oncol 1997 15(3) 987-93. 

Muggia, E. M., Hainsworth, J. D., Jeffers, S., Miller, R, Groshan, S., Tan, M., Roman, L., Uziely, B., Muderspach, L., Garcia, A., Burnett, A., Greco, E A. Phase 11 study of liposomal doxorubicin unrefractory ovarian cancer anti-tumor activity and toxicity modification by liposomal encapsulation. J. Clin. Oncol. 1997, 75, 987—993. 

Sulfonylureas. The hypoglycemic effect of sulfonylureas was first noted in the early 1940s when several patients died in hypoglycemic coma after testing glyprothia2ole, a synthetic sulfonamide used to treat typhoid. Chemical modifications which enhanced activity and lowered toxicity led to the development of the first-generation sulfonylureas. Carbutamide [339-43-5] the first commercial sulfonylurea, came onto the European... 

Miscellaneous. Electron beams can be used to decompose a gas such as silver chloride and simultaneously deposit silver metal. An older technique is the thermal decomposition of volatile and extremely toxic gases such as nickel carbonyl [13463-39-3] Ni(CO)4, to form dense deposits or dendritic coatings by modification of coating parameters. 

Elemental phosphoms is produced and marketed in the a-form of white or yellow phosphoms, the tetrahedral ahotrope. A small amount of ted amorphous phosphoms, P, is produced by conversion from white phosphoms. White phosphoms as the element is characterized by its combustion in air to form phosphoms pentoxide. Consequentiy, white phosphoms is generally stored and handled under water. Elemental white phosphoms is also highly toxic, and suitable precautions ate requited by those who manufacture or handle it. The black phosphoms modification prepared under high pressure does not have commercial importance. 

Although the antibacterial spectmm is similar for many of the sulfas, chemical modifications of the parent molecule have produced compounds with a variety of absorption, metaboHsm, tissue distribution, and excretion characteristics. Administration is typically oral or by injection. When absorbed, they tend to distribute widely in the body, be metabolized by the Hver, and excreted in the urine. Toxic reactions or untoward side effects have been characterized as blood dyscrasias crystal deposition in the kidneys, especially with insufficient urinary output and allergic sensitization. Selection of organisms resistant to the sulfonamides has been observed, but has not been correlated with cross-resistance to other antibiotic families (see Antibacterial AGENTS, synthetic-sulfonamides). 

Purification. Hemoglobin is provided by the red blood ceU in highly purified form. However, the red ceU contains many enzymes and other proteins, and red ceU membranes contain many components that could potentially cause toxicity problems. Furthermore, plasma proteins and other components could cause toxic reactions in recipients of hemoglobin preparations. The chemical modification reactions discussed herein are not specific for hemoglobin and may modify other proteins as well. Indeed, multifimctional reagents could actually couple hemoglobin to nonhemoglobin proteins. 

From the various modifications that have been made on the phenylbutazone structure in order to increase activity and reduce toxicity it has been found that the activity persists when methyl, chloro, hydroxy or nitro groups are introduced into the para position of one or both benzene rings (see oxyphenbutazone (712) as an example). Mofebutazone (714) has also been used in Europe for several years as an antirheumatic drug. 

The aqueous micellai solutions of some surfactants exhibit the cloud point, or turbidity, phenomenon when the solution is heated or cooled above or below a certain temperature. Then the phase sepai ation into two isotropic liquid phases occurs a concentrated phase containing most of the surfactant and an aqueous phase containing a surfactant concentration close to the critical micellar concentration. The anionic surfactant solutions show this phenomenon in acid media without any temperature modifications. The aim of the present work is to explore the analytical possibilities of acid-induced cloud point extraction in the extraction and preconcentration of polycyclic ai omatic hydrocai bons (PAHs) from water solutions. The combination of extraction, preconcentration and luminescence detection of PAHs in one step under their trace determination in objects mentioned allows to exclude the use of lai ge volumes of expensive, high-purity and toxic organic solvents and replace the known time and solvent consuming procedures by more simple and convenient methods. 

A further class of ethylene-vinyl acetate copolymer exists where the vinyl acetate content is of the order of 3 mole %. These materials are best considered as a modification of low-density polyethylene, where the low-cost comonomer introduces additional irregularity into the structure, reducing crystallinity and increasing flexibility, softness and, in the case of film, surface gloss. They have extensive clearance as non-toxic materials. 

Information provided in Part III. Section 8. of Form R is optional. In this section, you may identify waste minimization efforts relating to the reported toxic chemical. Waste minimization reduces the amount of the toxic chemicai in wastes by reducing waste generation or by recycling. This can be accomplished by equipment changes, process modifications, product reformulation, chemical substitutions, or other techniques. Waste minimization refers exclusively to practices which prevent the generation of wastes. Treatment or disposal does not minimize waste and should not be reported In this section. Recycling or reuse of a toxic chemical is considered waste minimization. Waste minimization applies to air emissions and wastewater, as well as to liquid or solid mate-... 

Source reduction includes any in-plant actions to reduce the quantity or the toxicity of the waste at the source. Examples include equipment modification, design and operational changes of the process, reformulation or redesign of products, substitution of raw materials, and use of environmentally benign chemical reactions. 

The tank trucks were not fitted with relief valves—normal European practice for toxic liquids. The study showed that the plant was designed for a higher pressure than the tank trucks and that in certain circumstances they could be overpressured. Modifications were made. 

The Chemical Process Industry (CPI) uses various quantitative and qualitative techniques to assess the reliability and risk of process equipment, process systems, and chemical manufacturing operations. These techniques identify the interactions of equipment, systems, and persons that have potentially undesirable consequences. In the case of reliability analyses, the undesirable consequences (e.g., plant shutdown, excessive downtime, or production of off-specification product) are those incidents which reduce system profitability through loss of production and increased maintenance costs. In the case of risk analyses, the primary concerns are human injuries, environmental impacts, and system damage caused by occurrence of fires, explosions, toxic material releases, and related hazards. Quantification of risk in terms of the severity of the consequences and the likelihood of occurrence provides the manager of the system with an important decisionmaking tool. By using the results of a quantitative risk analysis, we are better able to answer such questions as, Which of several candidate systems poses the least risk Are risk reduction modifications necessary and What modifications would be most effective in reducing risk ... 

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