Arsenicals: Inorganic or organic compounds that contain arsenic.Arsenic: A shiny gray element with atomic symbol As, atomic number 33, and atomic weight 75. It occurs throughout the universe, mostly in the form of metallic arsenides. Most forms are toxic. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), arsenic and certain arsenic compounds have been listed as known carcinogens. (From Merck Index, 11th ed)Arsenic Poisoning: Disorders associated with acute or chronic exposure to compounds containing ARSENIC (ARSENICALS) which may be fatal. Acute oral ingestion is associated with gastrointestinal symptoms and an encephalopathy which may manifest as SEIZURES, mental status changes, and COMA. Chronic exposure is associated with mucosal irritation, desquamating rash, myalgias, peripheral neuropathy, and white transverse (Mees) lines in the fingernails. (Adams et al., Principles of Neurology, 6th ed, p1212)Cacodylic Acid: An arsenical that has been used as a dermatologic agent and as an herbicide.Arsenites: Inorganic salts or organic esters of arsenious acid.Melarsoprol: Arsenical used in trypanosomiases. It may cause fatal encephalopathy and other undesirable side effects.Ion Pumps: A general class of integral membrane proteins that transport ions across a membrane against an electrochemical gradient.Arsenite Transporting ATPases: Efflux pumps that use the energy of ATP hydrolysis to pump arsenite across a membrane. They are primarily found in prokaryotic organisms, where they play a role in protection against excess intracellular levels of arsenite ions.Antimony: A metallic element that has the atomic symbol Sb, atomic number 51, and atomic weight 121.75. It is used as a metal alloy and as medicinal and poisonous salts. It is toxic and an irritant to the skin and the mucous membranes.Arsenates: Inorganic or organic salts and esters of arsenic acid.Roxarsone: An arsenic derivative which has anticoccidial action and promotes growth in animals.Trypanocidal Agents: Agents destructive to the protozoal organisms belonging to the suborder TRYPANOSOMATINA.Dimercaprol: An anti-gas warfare agent that is effective against Lewisite (dichloro(2-chlorovinyl)arsine) and formerly known as British Anti-Lewisite or BAL. It acts as a chelating agent and is used in the treatment of arsenic, gold, and other heavy metal poisoning.Diminazene: An effective trypanocidal agent.Pentamidine: Antiprotozoal agent effective in trypanosomiasis, leishmaniasis, and some fungal infections; used in treatment of PNEUMOCYSTIS pneumonia in HIV-infected patients. It may cause diabetes mellitus, central nervous system damage, and other toxic effects.Oxides: Binary compounds of oxygen containing the anion O(2-). The anion combines with metals to form alkaline oxides and non-metals to form acidic oxides.Aquaglyceroporins: A subgroup of aquaporins that transport WATER; GLYCEROL; and other small solutes across CELL MEMBRANES.Bowen's Disease: A persistent progressive non-elevated red scaly or crusted plaque which is due to an intradermal carcinoma and is potentially malignant. Atypical squamous cells proliferate through the whole thickness of the epidermis. The lesions may occur anywhere on the skin surface or on mucosal surfaces. The cause most frequently found is trivalent arsenic compounds. Freezing, cauterization or diathermy coagulation is often effective. (From Rook et al., Textbook of Dermatology, 4th ed, pp2428-9)Sodium Compounds: Inorganic compounds that contain sodium as an integral part of the molecule.Water Pollutants, Chemical: Chemical compounds which pollute the water of rivers, streams, lakes, the sea, reservoirs, or other bodies of water.Drinking Water: Water that is intended to be ingested.Nucleoside Transport Proteins: Proteins involved in the transport of NUCLEOSIDES across cellular membranes.Methylation: Addition of methyl groups. In histo-chemistry methylation is used to esterify carboxyl groups and remove sulfate groups by treating tissue sections with hot methanol in the presence of hydrochloric acid. (From Stedman, 25th ed)R Factors: A class of plasmids that transfer antibiotic resistance from one bacterium to another by conjugation.Methyltransferases: A subclass of enzymes of the transferase class that catalyze the transfer of a methyl group from one compound to another. (Dorland, 28th ed) EC 2.1.1.Trypanosoma brucei brucei: A hemoflagellate subspecies of parasitic protozoa that causes nagana in domestic and game animals in Africa. It apparently does not infect humans. It is transmitted by bites of tsetse flies (Glossina).Urothelium: The epithelial lining of the URINARY TRACT.Glutathione: A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.Crithidia fasciculata: A species of monogenetic, parasitic protozoa usually found in insects.Trypanosoma: A genus of flagellate protozoans found in the blood and lymph of vertebrates and invertebrates, both hosts being required to complete the life cycle.Skin DiseasesOrganometallic Compounds: A class of compounds of the type R-M, where a C atom is joined directly to any other element except H, C, N, O, F, Cl, Br, I, or At. (Grant & Hackh's Chemical Dictionary, 5th ed)Spectrophotometry, Atomic: Spectrophotometric techniques by which the absorption or emmision spectra of radiation from atoms are produced and analyzed.Trypanosomiasis, African: A disease endemic among people and animals in Central Africa. It is caused by various species of trypanosomes, particularly T. gambiense and T. rhodesiense. Its second host is the TSETSE FLY. Involvement of the central nervous system produces "African sleeping sickness." Nagana is a rapidly fatal trypanosomiasis of horses and other animals.Sulfides: Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties.Medicine, Traditional: Systems of medicine based on cultural beliefs and practices handed down from generation to generation. The concept includes mystical and magical rituals (SPIRITUAL THERAPIES); PHYTOTHERAPY; and other treatments which may not be explained by modern medicine.Sulfhydryl Compounds: Compounds containing the -SH radical.Operon: In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.Multienzyme Complexes: Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.Urinary Bladder: A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.Drug Resistance: Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.Cysteine: A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.Adenosine Triphosphatases: A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.Biotransformation: The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.Carcinogens: Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.Rats, Inbred F344Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Environmental Exposure: The exposure to potentially harmful chemical, physical, or biological agents in the environment or to environmental factors that may include ionizing radiation, pathogenic organisms, or toxic chemicals.Kinetics: The rate dynamics in chemical or physical systems.Drug Resistance, Microbial: The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).Disulfides: Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.