Spondylarthritis: Inflammation of the joints of the SPINE, the intervertebral articulations.HLA-B27 Antigen: A specific HLA-B surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-B*27 allele family.Rats, Transgenic: Laboratory rats that have been produced from a genetically manipulated rat EGG or rat EMBRYO, MAMMALIAN. They contain genes from another species.Sacroiliac Joint: The immovable joint formed by the lateral surfaces of the SACRUM and ILIUM.Sacroiliitis: Inflammation of the SACROILIAC JOINT. It is characterized by lower back pain, especially upon walking, fever, UVEITIS; PSORIASIS; and decreased range of motion. Many factors are associated with and cause sacroiliitis including infection; injury to spine, lower back, and pelvis; DEGENERATIVE ARTHRITIS; and pregnancy.Spondylitis, Ankylosing: A chronic inflammatory condition affecting the axial joints, such as the SACROILIAC JOINT and other intervertebral or costovertebral joints. It occurs predominantly in young males and is characterized by pain and stiffness of joints (ANKYLOSIS) with inflammation at tendon insertions.Synovial Membrane: The inner membrane of a joint capsule surrounding a freely movable joint. It is loosely attached to the external fibrous capsule and secretes SYNOVIAL FLUID.Arthritis, Rheumatoid: A chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. Etiology is unknown, but autoimmune mechanisms have been implicated.C-Reactive Protein: A plasma protein that circulates in increased amounts during inflammation and after tissue damage.Benzoylarginine-2-Naphthylamide: An enzyme substrate which permits the measurement of peptide hydrolase activity, e.g. trypsin and thrombin. The enzymes liberate 2-naphthylamine, which is measured by colorimetric procedures.Spondylitis: Inflammation of the SPINE. This includes both arthritic and non-arthritic conditions.Medical History Taking: Acquiring information from a patient on past medical conditions and treatments.Spine: The spinal or vertebral column.Translational Medical Research: The application of discoveries generated by laboratory research and preclinical studies to the development of clinical trials and studies in humans. A second area of translational research concerns enhancing the adoption of best practices.Research: Critical and exhaustive investigation or experimentation, having for its aim the discovery of new facts and their correct interpretation, the revision of accepted conclusions, theories, or laws in the light of newly discovered facts, or the practical application of such new or revised conclusions, theories, or laws. (Webster, 3d ed)Biomedical Research: Research that involves the application of the natural sciences, especially biology and physiology, to medicine.Clinical Trials as Topic: Works about pre-planned studies of the safety, efficacy, or optimum dosage schedule (if appropriate) of one or more diagnostic, therapeutic, or prophylactic drugs, devices, or techniques selected according to predetermined criteria of eligibility and observed for predefined evidence of favorable and unfavorable effects. This concept includes clinical trials conducted both in the U.S. and in other countries.Research Design: A plan for collecting and utilizing data so that desired information can be obtained with sufficient precision or so that an hypothesis can be tested properly.Research Personnel: Those individuals engaged in research.Research Support as Topic: Financial support of research activities.New JerseyTreatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Drug Substitution: The practice of replacing one prescribed drug with another that is expected to have the same clinical or psychological effect.Drug Administration Schedule: Time schedule for administration of a drug in order to achieve optimum effectiveness and convenience.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Antirheumatic Agents: Drugs that are used to treat RHEUMATOID ARTHRITIS.Arthritis, Psoriatic: A type of inflammatory arthritis associated with PSORIASIS, often involving the axial joints and the peripheral terminal interphalangeal joints. It is characterized by the presence of HLA-B27-associated SPONDYLARTHROPATHY, and the absence of rheumatoid factor.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Cross-Over Studies: Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Safety: Freedom from exposure to danger and protection from the occurrence or risk of injury or loss. It suggests optimal precautions in the workplace, on the street, in the home, etc., and includes personal safety as well as the safety of property.Rheumatology: A subspecialty of internal medicine concerned with the study of inflammatory or degenerative processes and metabolic derangement of connective tissue structures which pertain to a variety of musculoskeletal disorders, such as arthritis.Arthritis, Juvenile: Arthritis of children, with onset before 16 years of age. The terms juvenile rheumatoid arthritis (JRA) and juvenile idiopathic arthritis (JIA) refer to classification systems for chronic arthritis in children. Only one subtype of juvenile arthritis (polyarticular-onset, rheumatoid factor-positive) clinically resembles adult rheumatoid arthritis and is considered its childhood equivalent.Pediatrics: A medical specialty concerned with maintaining health and providing medical care to children from birth to adolescence.Rheumatic Diseases: Disorders of connective tissue, especially the joints and related structures, characterized by inflammation, degeneration, or metabolic derangement.DimethylformamideDermatomyositis: A subacute or chronic inflammatory disease of muscle and skin, marked by proximal muscle weakness and a characteristic skin rash. The illness occurs with approximately equal frequency in children and adults. The skin lesions usually take the form of a purplish rash (or less often an exfoliative dermatitis) involving the nose, cheeks, forehead, upper trunk, and arms. The disease is associated with a complement mediated intramuscular microangiopathy, leading to loss of capillaries, muscle ischemia, muscle-fiber necrosis, and perifascicular atrophy. The childhood form of this disease tends to evolve into a systemic vasculitis. Dermatomyositis may occur in association with malignant neoplasms. (From Adams et al., Principles of Neurology, 6th ed, pp1405-6)TexasMaackia: A plant genus of the family FABACEAE. It contains a hemagglutinin.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Erythrina: A genus of leguminous shrubs or trees, mainly tropical, yielding useful compounds such as ALKALOIDS and PLANT LECTINS.Polymorphism, Genetic: The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.Antibody Affinity: A measure of the binding strength between antibody and a simple hapten or antigen determinant. It depends on the closeness of stereochemical fit between antibody combining sites and antigen determinants, on the size of the area of contact between them, and on the distribution of charged and hydrophobic groups. It includes the concept of "avidity," which refers to the strength of the antigen-antibody bond after formation of reversible complexes.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Microscopy, Phase-Contrast: A form of interference microscopy in which variations of the refracting index in the object are converted into variations of intensity in the image. This is achieved by the action of a phase plate.Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.Killer Cells, Natural: Bone marrow-derived lymphocytes that possess cytotoxic properties, classically directed against transformed and virus-infected cells. Unlike T CELLS; and B CELLS; NK CELLS are not antigen specific. The cytotoxicity of natural killer cells is determined by the collective signaling of an array of inhibitory and stimulatory CELL SURFACE RECEPTORS. A subset of T-LYMPHOCYTES referred to as NATURAL KILLER T CELLS shares some of the properties of this cell type.Tumor Necrosis Factor-alpha: Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.Receptors, Tumor Necrosis Factor: Cell surface receptors that bind TUMOR NECROSIS FACTORS and trigger changes which influence the behavior of cells.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.