Raccoon Dogs: The lone species in the genus Nyctereutes, family CANIDAE. It is found in the woodland zone from southeastern Siberia to Vietnam and on the main islands of Japan.Bites and StingsBonding, Human-Pet: The emotional attachment of individuals to PETS.Pets: Animals kept by humans for companionship and enjoyment, as opposed to DOMESTIC ANIMALS such as livestock or farm animals, which are kept for economic reasons.Cat Diseases: Diseases of the domestic cat (Felis catus or F. domesticus). This term does not include diseases of the so-called big cats such as CHEETAHS; LIONS; tigers, cougars, panthers, leopards, and other Felidae for which the heading CARNIVORA is used.Wolves: Any of several large carnivorous mammals of the family CANIDAE that usually hunt in packs.Dirofilaria immitis: A filarial parasite primarily of dogs but occurring also in foxes, wolves, and humans. The parasite is transmitted by mosquitoes.Dirofilariasis: Infection with nematodes of the genus DIROFILARIA, usually in animals, especially dogs, but occasionally in man.Leishmania infantum: A parasitic hemoflagellate of the subgenus Leishmania leishmania that infects man and animals and causes visceral leishmaniasis (LEISHMANIASIS, VISCERAL). Human infections are confined almost entirely to children. This parasite is commonly seen in dogs, other Canidae, and porcupines with humans considered only an accidental host. Transmission is by Phlebotomus sandflies.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Animals, Domestic: Animals which have become adapted through breeding in captivity to a life intimately associated with humans. They include animals domesticated by humans to live and breed in a tame condition on farms or ranches for economic reasons, including LIVESTOCK (specifically CATTLE; SHEEP; HORSES; etc.), POULTRY; and those raised or kept for pleasure and companionship, e.g., PETS; or specifically DOGS; CATS; etc.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Coronary Circulation: The circulation of blood through the CORONARY VESSELS of the HEART.Rabies: Acute VIRAL CNS INFECTION affecting mammals, including humans. It is caused by RABIES VIRUS and usually spread by contamination with virus-laden saliva of bites inflicted by rabid animals. Important animal vectors include the dog, cat, bat, fox, raccoon, skunk, and wolf.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Anesthesia: A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.Flea Infestations: Parasitic attack by members of the order SIPHONAPTERA.Heart: The hollow, muscular organ that maintains the circulation of the blood.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Distemper: A name for several highly contagious viral diseases of animals, especially canine distemper. In dogs, it is caused by the canine distemper virus (DISTEMPER VIRUS, CANINE). It is characterized by a diphasic fever, leukopenia, gastrointestinal and respiratory inflammation and sometimes, neurologic complications. In cats it is known as FELINE PANLEUKOPENIA.Vagus Nerve: The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).Hip Dysplasia, Canine: A hereditary disease of the hip joints in dogs. Signs of the disease may be evident any time after 4 weeks of age.Tick Infestations: Infestations with soft-bodied (Argasidae) or hard-bodied (Ixodidae) ticks.Leishmaniasis, Visceral: A chronic disease caused by LEISHMANIA DONOVANI and transmitted by the bite of several sandflies of the genera Phlebotomus and Lutzomyia. It is commonly characterized by fever, chills, vomiting, anemia, hepatosplenomegaly, leukopenia, hypergammaglobulinemia, emaciation, and an earth-gray color of the skin. The disease is classified into three main types according to geographic distribution: Indian, Mediterranean (or infantile), and African.Consciousness: Sense of awareness of self and of the environment.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Vascular Resistance: The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.Rhipicephalus sanguineus: A species of tick (TICKS) in the family IXODIDAE, distributed throughout the world but abundant in southern Europe. It will feed on a wide variety of MAMMALS, but DOGS are its preferred host. It transmits a large number of diseases including BABESIOSIS; THEILERIASIS; EHRLICHIOSIS; and MEDITERRANEAN SPOTTED FEVER.Myocardium: The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.Ehrlichia canis: Species of gram-negative bacteria in the family ANAPLASMATACEAE, causing EHRLICHIOSIS in DOGS. The most common vector is the brown dog tick. It can also cause disease in humans.Zoonoses: Diseases of non-human animals that may be transmitted to HUMANS or may be transmitted from humans to non-human animals.Cardiac Output: The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Halothane: A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)Distemper Virus, Canine: A species of MORBILLIVIRUS causing distemper in dogs, wolves, foxes, raccoons, and ferrets. Pinnipeds have also been known to contract Canine distemper virus from contact with domestic dogs.Feces: Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.Cardiac Pacing, Artificial: Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.Pressoreceptors: Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.Fatal Outcome: Death resulting from the presence of a disease in an individual, as shown by a single case report or a limited number of patients. This should be differentiated from DEATH, the physiological cessation of life and from MORTALITY, an epidemiological or statistical concept.Injections, Intravenous: Injections made into a vein for therapeutic or experimental purposes.Carotid Sinus: The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure.Ctenocephalides: A genus of FLEAS in the family Pulicidae. It includes the cat flea (Ctenocephalides felis), one of the most common species on earth.Propranolol: A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.Rabies Vaccines: Vaccines or candidate vaccines used to prevent and treat RABIES. The inactivated virus vaccine is used for preexposure immunization to persons at high risk of exposure, and in conjunction with rabies immunoglobulin, for postexposure prophylaxis.Ehrlichiosis: A tick-borne disease characterized by FEVER; HEADACHE; myalgias; ANOREXIA; and occasionally RASH. It is caused by several bacterial species and can produce disease in DOGS; CATTLE; SHEEP; GOATS; HORSES; and humans. The primary species causing human disease are EHRLICHIA CHAFFEENSIS; ANAPLASMA PHAGOCYTOPHILUM; and Ehrlichia ewingii.Foxes: Any of several carnivores in the family CANIDAE, that possess erect ears and long bushy tails and are smaller than WOLVES. They are classified in several genera and found on all continents except Antarctica.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Coronary Vessels: The veins and arteries of the HEART.Regional Blood Flow: The flow of BLOOD through or around an organ or region of the body.Vagotomy: The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.Euthanasia, Animal: The killing of animals for reasons of mercy, to control disease transmission or maintain the health of animal populations, or for experimental purposes (ANIMAL EXPERIMENTATION).Administration, Oral: The giving of drugs, chemicals, or other substances by mouth.Norepinephrine: Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.Atropine: An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.Reflex: An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.Adrenocortical Hyperfunction: Excess production of ADRENAL CORTEX HORMONES such as ALDOSTERONE; HYDROCORTISONE; DEHYDROEPIANDROSTERONE; and/or ANDROSTENEDIONE. Hyperadrenal syndromes include CUSHING SYNDROME; HYPERALDOSTERONISM; and VIRILISM.Breeding: The production of offspring by selective mating or HYBRIDIZATION, GENETIC in animals or plants.Lameness, Animal: A departure from the normal gait in animals.Denervation: The resection or removal of the nerve to an organ or part. (Dorland, 28th ed)Disease Reservoirs: Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (DISEASE VECTORS) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks.Babesia: A genus of tick-borne protozoan parasites that infests the red blood cells of mammals, including humans. There are many recognized species, and the distribution is world-wide.Stellate Ganglion: A paravertebral sympathetic ganglion formed by the fusion of the inferior cervical and first thoracic ganglia.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.Heart Conduction System: An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.Electrocardiography: Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.Ehrlichia: Small, often pleomorphic, coccoid to ellipsoidal organisms occurring intracytoplasmically in circulating LYMPHOCYTES. They are the etiologic agents of tick-borne diseases of humans; DOGS; CATTLE; SHEEP; GOATS; and HORSES.Acaricides: A pesticide or chemical agent that kills mites and ticks. This is a large class that includes carbamates, formamides, organochlorines, organophosphates, etc, that act as antibiotics or growth regulators.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Acepromazine: A phenothiazine that is used in the treatment of PSYCHOSES.Carnivora: An order of MAMMALS, usually flesh eaters with appropriate dentition. Suborders include the terrestrial carnivores Fissipedia, and the aquatic carnivores PINNIPEDIA.Chloralose: A derivative of CHLORAL HYDRATE that was used as a sedative but has been replaced by safer and more effective drugs. Its most common use is as a general anesthetic in animal experiments.Bile: An emulsifying agent produced in the LIVER and secreted into the DUODENUM. Its composition includes BILE ACIDS AND SALTS; CHOLESTEROL; and ELECTROLYTES. It aids DIGESTION of fats in the duodenum.Random Allocation: A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.Babesiosis: A group of tick-borne diseases of mammals including ZOONOSES in humans. They are caused by protozoa of the genus BABESIA, which parasitize erythrocytes, producing hemolysis. In the U.S., the organism's natural host is mice and transmission is by the deer tick IXODES SCAPULARIS.Epinephrine: The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.Parasitic Diseases, Animal: Infections or infestations with parasitic organisms. The infestation may be experimental or veterinary.Isoflurane: A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.Heart Ventricles: The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.Ventricular Function: The hemodynamic and electrophysiological action of the HEART VENTRICLES.Sertoli Cell Tumor: Gonadal neoplasm composed entirely of SERTOLI CELLS or may have a component of GRANULOSA CELLS. Some of the Sertoli cell tumors produce ESTROGEN or ANDROGENS, but seldom in sufficient quantity to cause clinical symptoms such as FEMINIZATION or masculinization (VIRILISM).Canidae: A family of terrestrial carnivores with long snouts and non-retractable claws. Members include COYOTES; DOGS; FOXES; JACKALS; RACCOON DOGS; and WOLVES.Veterinary Medicine: The medical science concerned with the prevention, diagnosis, and treatment of diseases in animals.Rabies virus: The type species of LYSSAVIRUS causing rabies in humans and other animals. Transmission is mostly by animal bites through saliva. The virus is neurotropic multiplying in neurons and myotubes of vertebrates.Stifle: In horses, cattle, and other quadrupeds, the joint between the femur and the tibia, corresponding to the human knee.Thelazioidea: A superfamily of parasitic nematodes which includes three genera: Thelazia, Spirocerca, and GNATHOSTOMA. Only Thelazia and GNATHOSTOMA occasionally occur in man.Medetomidine: An agonist of RECEPTORS, ADRENERGIC ALPHA-2 that is used in veterinary medicine for its analgesic and sedative properties. It is the racemate of DEXMEDETOMIDINE.Stomach: An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Pressure: A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Blood Volume: Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.Angiostrongylus: A genus of parasitic nematodes of the superfamily METASTRONGYLOIDEA. Two species, ANGIOSTRONGYLUS CANTONENSIS and A. vasorum, infest the lungs of rats and dogs, respectively. A. cantonensis is transmissible to man where it causes frequently fatal infection of the central nervous system.Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Neospora: A genus of protozoan parasites of the subclass COCCIDIA. Its species are parasitic in dogs, cattle, goats, and sheep, among others. N. caninum, a species that mainly infects dogs, is intracellular in neural and other cells of the body, multiplies by endodyogeny, has no parasitophorous vacuole, and has numerous rhoptries. It is known to cause lesions in many tissues, especially the brain and spinal cord as well as abortion in the expectant mother.Sciuridae: A family of the order Rodentia which contains 49 genera. Some of the more common genera are MARMOTA, which includes the marmot and woodchuck; Sciurus, the gray squirrel, S. carolinensis, and the fox squirrel, S. niger; Tamias, the eastern and western chipmunk; and Tamiasciurus, the red squirrel. The flying squirrels, except the scaly-tailed Anomaluridae, also belong to this family.Microspheres: Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.Seroepidemiologic Studies: EPIDEMIOLOGIC STUDIES based on the detection through serological testing of characteristic change in the serum level of specific ANTIBODIES. Latent subclinical infections and carrier states can thus be detected in addition to clinically overt cases.Refractory Period, Electrophysiological: The period of time following the triggering of an ACTION POTENTIAL when the CELL MEMBRANE has changed to an unexcitable state and is gradually restored to the resting (excitable) state. During the absolute refractory period no other stimulus can trigger a response. This is followed by the relative refractory period during which the cell gradually becomes more excitable and the stronger impulse that is required to illicit a response gradually lessens to that required during the resting state.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Respiration: The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).Anesthesia, Inhalation: Anesthesia caused by the breathing of anesthetic gases or vapors or by insufflating anesthetic gases or vapors into the respiratory tract.Infusions, Parenteral: The administration of liquid medication, nutrient, or other fluid through some other route than the alimentary canal, usually over minutes or hours, either by gravity flow or often by infusion pumping.Histocytochemistry: Study of intracellular distribution of chemicals, reaction sites, enzymes, etc., by means of staining reactions, radioactive isotope uptake, selective metal distribution in electron microscopy, or other methods.Meningoencephalitis: An inflammatory process involving the brain (ENCEPHALITIS) and meninges (MENINGITIS), most often produced by pathogenic organisms which invade the central nervous system, and occasionally by toxins, autoimmune disorders, and other conditions.Models, Animal: Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.Diuresis: An increase in the excretion of URINE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Bartonella Infections: Infections by the genus BARTONELLA. Bartonella bacilliformis can cause acute febrile anemia, designated Oroya fever, and a benign skin eruption, called verruga peruana. BARTONELLA QUINTANA causes TRENCH FEVER, while BARTONELLA HENSELAE is the etiologic agent of bacillary angiomatosis (ANGIOMATOSIS, BACILLARY) and is also one of the causes of CAT-SCRATCH DISEASE in immunocompetent patients.Arrhythmias, Cardiac: Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.Sympathetic Nervous System: The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.Ectoparasitic Infestations: Infestations by PARASITES which live on, or burrow into, the surface of their host's EPIDERMIS. Most ectoparasites are ARTHROPODS.Influenza A Virus, H3N8 Subtype: A subtype of INFLUENZA A VIRUS comprised of the surface proteins hemagglutinin 3 and neuraminidase 8. The H3N8 subtype has frequently been found in horses.Echinococcus granulosus: A species of hydatid tapeworm (class CESTODA) in the family Taeniidae, whose adult form infects the DIGESTIVE TRACT of DOGS, other canines, and CATS. The larval form infects SHEEP; PIGS; HORSES; and may infect humans, where it migrates to various organs and forms permanent HYDATID CYSTS.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Portal Vein: A short thick vein formed by union of the superior mesenteric vein and the splenic vein.Parvovirus, Canine: A species of the genus PARVOVIRUS and a host range variant of FELINE PANLEUKOPENIA VIRUS. It causes a highly infectious fulminating ENTERITIS in dogs producing high mortality. It is distinct from CANINE MINUTE VIRUS, a species in the genus BOCAVIRUS. This virus can also infect cats and mink.Ownership: The legal relation between an entity (individual, group, corporation, or-profit, secular, government) and an object. The object may be corporeal, such as equipment, or completely a creature of law, such as a patent; it may be movable, such as an animal, or immovable, such as a building.Hematocrit: The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.Isoproterenol: Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.Adenoviruses, Canine: Species of the genus MASTADENOVIRUS that causes fever, edema, vomiting, and diarrhea in dogs and encephalitis in foxes. Epizootics have also been caused in bears, wolves, coyotes, and skunks. The official species name is Canine adenovirus and it contains two serotypes.Coccidiosis: Protozoan infection found in animals and man. It is caused by several different genera of COCCIDIA.Injections, Intra-Arterial: Delivery of drugs into an artery.Glucagon: A 29-amino acid pancreatic peptide derived from proglucagon which is also the precursor of intestinal GLUCAGON-LIKE PEPTIDES. Glucagon is secreted by PANCREATIC ALPHA CELLS and plays an important role in regulation of BLOOD GLUCOSE concentration, ketone metabolism, and several other biochemical and physiological processes. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1511)Renin: A highly specific (Leu-Leu) endopeptidase that generates ANGIOTENSIN I from its precursor ANGIOTENSINOGEN, leading to a cascade of reactions which elevate BLOOD PRESSURE and increase sodium retention by the kidney in the RENIN-ANGIOTENSIN SYSTEM. The enzyme was formerly listed as EC 3.4.99.19.Anal Gland Neoplasms: Tumors or cancer of the anal gland.Dirofilaria: A genus of filarial nematodes. Various immature species have been found to infect the eyes or subcutaneous tissue in humans.Histiocytic Sarcoma: Malignant neoplasms composed of MACROPHAGES or DENDRITIC CELLS. Most histiocytic sarcomas present as localized tumor masses without a leukemic phase. Though the biological behavior of these neoplasms resemble lymphomas, their cell lineage is histiocytic not lymphoid.Endocardium: The innermost layer of the heart, comprised of endothelial cells.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Blood Gas Analysis: Measurement of oxygen and carbon dioxide in the blood.Tachycardia: Abnormally rapid heartbeat, usually with a HEART RATE above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia.Pentobarbital: A short-acting barbiturate that is effective as a sedative and hypnotic (but not as an anti-anxiety) agent and is usually given orally. It is prescribed more frequently for sleep induction than for sedation but, like similar agents, may lose its effectiveness by the second week of continued administration. (From AMA Drug Evaluations Annual, 1994, p236)Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Liver Circulation: The circulation of BLOOD through the LIVER.Hindlimb: Either of two extremities of four-footed non-primate land animals. It usually consists of a FEMUR; TIBIA; and FIBULA; tarsals; METATARSALS; and TOES. (From Storer et al., General Zoology, 6th ed, p73)Adrenergic alpha-Antagonists: Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma.Echinococcosis: An infection caused by the infestation of the larval form of tapeworms of the genus Echinococcus. The liver, lungs, and kidney are the most common areas of infestation.Heart Block: Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects.Coronavirus, Canine: A species of CORONAVIRUS infecting dogs. Onset of symptoms is usually sudden and includes vomiting, diarrhea, and dehydration.Natriuresis: Sodium excretion by URINATION.Macaca fascicularis: A species of the genus MACACA which typically lives near the coast in tidal creeks and mangrove swamps primarily on the islands of the Malay peninsula.Depression, Chemical: The decrease in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.Horses: Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Metabolic Clearance Rate: Volume of biological fluid completely cleared of drug metabolites as measured in unit time. Elimination occurs as a result of metabolic processes in the kidney, liver, saliva, sweat, intestine, heart, brain, or other site.Intercostal Muscles: Respiratory muscles that arise from the lower border of one rib and insert into the upper border of the adjoining rib, and contract during inspiration or respiration. (From Stedman, 25th ed)Bartonella: A genus of gram-negative bacteria characteristically appearing in chains of several segmenting organisms. It occurs in man and arthropod vectors and is found only in the Andes region of South America. This genus is the etiologic agent of human bartonellosis. The genus Rochalimaea, once considered a separate genus, has recently been combined with the genus Bartonella as a result of high levels of relatedness in 16S rRNA sequence data and DNA hybridization data.Ticks: Blood-sucking acarid parasites of the order Ixodida comprising two families: the softbacked ticks (ARGASIDAE) and hardbacked ticks (IXODIDAE). Ticks are larger than their relatives, the MITES. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many TICK-BORNE DISEASES, including the transmission of ROCKY MOUNTAIN SPOTTED FEVER; TULAREMIA; BABESIOSIS; AFRICAN SWINE FEVER; and RELAPSING FEVER. (From Barnes, Invertebrate Zoology, 5th ed, pp543-44)Tissue Distribution: Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.Aminohippuric Acids: A group of glycine amides of aminobenzoic acids.Mite Infestations: Infestations with arthropods of the subclass ACARI, superorder Acariformes.Phentolamine: A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Gastric Fistula: Abnormal passage communicating with the STOMACH.Adrenergic beta-Antagonists: Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.Siphonaptera: An order of parasitic, blood-sucking, wingless INSECTS with the common name of fleas.Enflurane: An extremely stable inhalation anesthetic that allows rapid adjustments of anesthesia depth with little change in pulse or respiratory rate.Capnocytophaga: A gram-negative gliding bacterium isolated from the oral cavity. It is a pathogen often causing PERIODONTITIS.Hexamethonium Compounds: Compounds containing the hexamethylenebis(trimethylammonium) cation. Members of this group frequently act as antihypertensive agents and selective ganglionic blocking agents.Pericardium: A conical fibro-serous sac surrounding the HEART and the roots of the great vessels (AORTA; VENAE CAVAE; PULMONARY ARTERY). Pericardium consists of two sacs: the outer fibrous pericardium and the inner serous pericardium. The latter consists of an outer parietal layer facing the fibrous pericardium, and an inner visceral layer (epicardium) resting next to the heart, and a pericardial cavity between these two layers.Leishmaniasis: A disease caused by any of a number of species of protozoa in the genus LEISHMANIA. There are four major clinical types of this infection: cutaneous (Old and New World) (LEISHMANIASIS, CUTANEOUS), diffuse cutaneous (LEISHMANIASIS, DIFFUSE CUTANEOUS), mucocutaneous (LEISHMANIASIS, MUCOCUTANEOUS), and visceral (LEISHMANIASIS, VISCERAL).Animals, Wild: Animals considered to be wild or feral or not adapted for domestic use. It does not include wild animals in zoos for which ANIMALS, ZOO is available.Catecholamines: A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.Nitroglycerin: A volatile vasodilator which relieves ANGINA PECTORIS by stimulating GUANYLATE CYCLASE and lowering cytosolic calcium. It is also sometimes used for TOCOLYSIS and explosives.Adenosine: A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.Pancreas: A nodular organ in the ABDOMEN that contains a mixture of ENDOCRINE GLANDS and EXOCRINE GLANDS. The small endocrine portion consists of the ISLETS OF LANGERHANS secreting a number of hormones into the blood stream. The large exocrine portion (EXOCRINE PANCREAS) is a compound acinar gland that secretes several digestive enzymes into the pancreatic ductal system that empties into the DUODENUM.Toxocariasis: Infection by round worms of the genus TOXOCARA, usually found in wild and domesticated cats and dogs and foxes, except for the larvae, which may produce visceral and ocular larva migrans in man.Ventricular Function, Left: The hemodynamic and electrophysiological action of the left HEART VENTRICLE. Its measurement is an important aspect of the clinical evaluation of patients with heart disease to determine the effects of the disease on cardiac performance.Antibodies, Protozoan: Immunoglobulins produced in a response to PROTOZOAN ANTIGENS.Duodenum: The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.Ventricular Fibrillation: A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.Anal Sacs: A pair of anal glands or sacs, located on either side of the ANUS, that produce and store a dark, foul-smelling fluid in carnivorous animals such as MEPHITIDAE and DOGS. The expelled fluid is used as a defensive repellent (in skunks) or a material to mark territory (in dogs).Renal Circulation: The circulation of the BLOOD through the vessels of the KIDNEY.Enzyme-Linked Immunosorbent Assay: An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.VeratrineConstriction: The act of constricting.Physical Exertion: Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.Sinoatrial Node: The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).Hospitals, AnimalHalf-Life: The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.Secretin: A peptide hormone of about 27 amino acids from the duodenal mucosa that activates pancreatic secretion and lowers the blood sugar level. (USAN and the USP Dictionary of Drug Names, 1994, p597)Gastrointestinal Motility: The motor activity of the GASTROINTESTINAL TRACT.Radioisotopes: Isotopes that exhibit radioactivity and undergo radioactive decay. (From Grant & Hackh's Chemical Dictionary, 5th ed & McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Arteries: The vessels carrying blood away from the heart.Anti-Arrhythmia Agents: Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade.Nitro Compounds: Compounds having the nitro group, -NO2, attached to carbon. When attached to nitrogen they are nitramines and attached to oxygen they are NITRATES.Phenoxybenzamine: An alpha-adrenergic antagonist with long duration of action. It has been used to treat hypertension and as a peripheral vasodilator.Drug Evaluation, Preclinical: Preclinical testing of drugs in experimental animals or in vitro for their biological and toxic effects and potential clinical applications.Gangliosidosis, GM1: An autosomal recessive neurodegenerative disorder caused by the absence or deficiency of BETA-GALACTOSIDASE. It is characterized by intralysosomal accumulation of G(M1) GANGLIOSIDE and oligosaccharides, primarily in neurons of the central nervous system. The infantile form is characterized by MUSCLE HYPOTONIA, poor psychomotor development, HIRSUTISM, hepatosplenomegaly, and facial abnormalities. The juvenile form features HYPERACUSIS; SEIZURES; and psychomotor retardation. The adult form features progressive DEMENTIA; ATAXIA; and MUSCLE SPASTICITY. (From Menkes, Textbook of Child Neurology, 5th ed, pp96-7)Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Infusions, Intravenous: The long-term (minutes to hours) administration of a fluid into the vein through venipuncture, either by letting the fluid flow by gravity or by pumping it.Blood Flow Velocity: A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.Raccoons: Carnivores of the genus Procyon of the family PROCYONIDAE. Two subgenera and seven species are currently recognized. They range from southern Canada to Panama and are found in several of the Caribbean Islands.Gastric Dilatation: Abnormal distention of the STOMACH due to accumulation of gastric contents that may reach 10 to 15 liters. Gastric dilatation may be the result of GASTRIC OUTLET OBSTRUCTION; ILEUS; GASTROPARESIS; or denervation.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Spirurida Infections: Infections with nematodes of the order SPIRURIDA.Motilin: A peptide of about 22-amino acids isolated from the DUODENUM. At low pH it inhibits gastric motor activity, whereas at high pH it has a stimulating effect.