Congo Red: An acid dye used in testing for hydrochloric acid in gastric contents. It is also used histologically to test for AMYLOIDOSIS.Congo: A republic in central Africa lying between GABON and DEMOCRATIC REPUBLIC OF THE CONGO and south of Cameroon. Its capital is Brazzaville.Democratic Republic of the Congo: A republic in central Africa, east of the REPUBLIC OF THE CONGO, south of the CENTRAL AFRICAN REPUBLIC and north of ANGOLA and ZAMBIA. The capital is Kinshasa.Amyloid: A fibrous protein complex that consists of proteins folded into a specific cross beta-pleated sheet structure. This fibrillar structure has been found as an alternative folding pattern for a variety of functional proteins. Deposits of amyloid in the form of AMYLOID PLAQUES are associated with a variety of degenerative diseases. The amyloid structure has also been found in a number of functional proteins that are unrelated to disease.Amyloidosis: A group of sporadic, familial and/or inherited, degenerative, and infectious disease processes, linked by the common theme of abnormal protein folding and deposition of AMYLOID. As the amyloid deposits enlarge they displace normal tissue structures, causing disruption of function. Various signs and symptoms depend on the location and size of the deposits.Shigella flexneri: A bacterium which is one of the etiologic agents of bacillary dysentery (DYSENTERY, BACILLARY) and sometimes of infantile gastroenteritis.Phenolsulfonphthalein: Red dye, pH indicator, and diagnostic aid for determination of renal function. It is used also for studies of the gastrointestinal and other systems.Monkeypox: A viral disease infecting PRIMATES and RODENTS. Its clinical presentation in humans is similar to SMALLPOX including FEVER; HEADACHE; COUGH; and a painful RASH. It is caused by MONKEYPOX VIRUS and is usually transmitted to humans through BITES or via contact with an animal's BLOOD. Interhuman transmission is relatively low (significantly less than smallpox).Microscopy, Polarization: Microscopy using polarized light in which phenomena due to the preferential orientation of optical properties with respect to the vibration plane of the polarized light are made visible and correlated parameters are made measurable.Monkeypox virus: A species of ORTHOPOXVIRUS causing an epidemic disease among captive primates.Birefringence: The property of nonisotropic media, such as crystals, whereby a single incident beam of light traverses the medium as two beams, each plane-polarized, the planes being at right angles to each other. (Cline et al., Dictionary of Visual Science, 4th ed)Porphyromonas: A genus of gram-negative, anaerobic, nonsporeforming, nonmotile rods or coccobacilli. Organisms in this genus had originally been classified as members of the BACTEROIDES genus but overwhelming biochemical and chemical findings indicated the need to separate them from other Bacteroides species, and hence, this new genus was created.Pentosan Sulfuric Polyester: A sulfated pentosyl polysaccharide with heparin-like properties.Hemin: Chloro(7,12-diethenyl-3,8,13,17-tetramethyl-21H,23H-porphine-2,18-dipropanoato(4-)-N(21),N(22),N(23),N(24)) ferrate(2-) dihydrogen.Staining and Labeling: The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.Agar: A complex sulfated polymer of galactose units, extracted from Gelidium cartilagineum, Gracilaria confervoides, and related red algae. It is used as a gel in the preparation of solid culture media for microorganisms, as a bulk laxative, in making emulsions, and as a supporting medium for immunodiffusion and immunoelectrophoresis.Helicobacter pylori: A spiral bacterium active as a human gastric pathogen. It is a gram-negative, urease-positive, curved or slightly spiral organism initially isolated in 1982 from patients with lesions of gastritis or peptic ulcers in Western Australia. Helicobacter pylori was originally classified in the genus CAMPYLOBACTER, but RNA sequencing, cellular fatty acid profiles, growth patterns, and other taxonomic characteristics indicate that the micro-organism should be included in the genus HELICOBACTER. It has been officially transferred to Helicobacter gen. nov. (see Int J Syst Bacteriol 1989 Oct;39(4):297-405).Helicobacter Infections: Infections with organisms of the genus HELICOBACTER, particularly, in humans, HELICOBACTER PYLORI. The clinical manifestations are focused in the stomach, usually the gastric mucosa and antrum, and the upper duodenum. This infection plays a major role in the pathogenesis of type B gastritis and peptic ulcer disease.Gastric Acid: Hydrochloric acid present in GASTRIC JUICE.Anti-Ulcer Agents: Various agents with different action mechanisms used to treat or ameliorate PEPTIC ULCER or irritation of the gastrointestinal tract. This has included ANTIBIOTICS to treat HELICOBACTER INFECTIONS; HISTAMINE H2 ANTAGONISTS to reduce GASTRIC ACID secretion; and ANTACIDS for symptomatic relief.Omeprazole: A 4-methoxy-3,5-dimethylpyridyl, 5-methoxybenzimidazole derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits an H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS.Amoxicillin: A broad-spectrum semisynthetic antibiotic similar to AMPICILLIN except that its resistance to gastric acid permits higher serum levels with oral administration.Gastritis, Atrophic: GASTRITIS with atrophy of the GASTRIC MUCOSA, the GASTRIC PARIETAL CELLS, and the mucosal glands leading to ACHLORHYDRIA. Atrophic gastritis usually progresses from chronic gastritis.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.Dietary Fiber: The remnants of plant cell walls that are resistant to digestion by the alimentary enzymes of man. It comprises various polysaccharides and lignins.Fibronectins: Glycoproteins found on the surfaces of cells, particularly in fibrillar structures. The proteins are lost or reduced when these cells undergo viral or chemical transformation. They are highly susceptible to proteolysis and are substrates for activated blood coagulation factor VIII. The forms present in plasma are called cold-insoluble globulins.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Polymers: Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).Bacteriology: The study of the structure, growth, function, genetics, and reproduction of bacteria, and BACTERIAL INFECTIONS.Environmental Microbiology: The study of microorganisms living in a variety of environments (air, soil, water, etc.) and their pathogenic relationship to other organisms including man.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Microbiology: The study of microorganisms such as fungi, bacteria, algae, archaea, and viruses.Bacteria: One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.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.Neutral Red: A vital dye used as an indicator and biological stain. Various adverse effects have been observed in biological systems.Nitroblue Tetrazolium: Colorless to yellow dye that is reducible to blue or black formazan crystals by certain cells; formerly used to distinguish between nonbacterial and bacterial diseases, the latter causing neutrophils to reduce the dye; used to confirm diagnosis of chronic granulomatous disease.Alcian Blue: A copper-containing dye used as a gelling agent for lubricants, for staining of bacteria and for the dyeing of histiocytes and fibroblasts in vivo.Xylenes: A family of isomeric, colorless aromatic hydrocarbon liquids, that contain the general formula C6H4(CH3)2. They are produced by the destructive distillation of coal or by the catalytic reforming of petroleum naphthenic fractions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Azo CompoundsTetrazolium Salts: Quaternary salts derived from tetrazoles. They are used in tests to distinguish between reducing sugars and simple aldehydes, for detection of dehydrogenase in tissues, cells, and bacteria, for determination of corticosteroids, and in color photography. (From Mall's Dictionary of Chemistry, 5th ed, p455)Methylene Blue: A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN.Amido Black: A dye used to stain proteins in electrophoretic techniques. It is used interchangeably with its acid form.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Aequorin: A photoprotein isolated from the bioluminescent jellyfish Aequorea. It emits visible light by an intramolecular reaction when a trace amount of calcium ion is added. The light-emitting moiety in the bioluminescence reaction is believed to be 2-amino-3-benzyl-5-(p-hydroxyphenyl)pyrazine (AF-350).Luminescent Measurements: Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.Transition Elements: Elements with partially filled d orbitals. They constitute groups 3-12 of the periodic table of elements.Inventions: A novel composition, device, or process, independently conceived de novo or derived from a pre-existing model.Intellectual Property: Property, such as patents, trademarks, and copyright, that results from creative effort. The Patent and Copyright Clause (Art. 1, Sec. 8, cl. 8) of the United States Constitution provides for promoting the progress of science and useful arts by securing for limited times to authors and inventors, the exclusive right to their respective writings and discoveries. (From Black's Law Dictionary, 5th ed, p1014)PubMed: A bibliographic database that includes MEDLINE as its primary subset. It is produced by the National Center for Biotechnology Information (NCBI), part of the NATIONAL LIBRARY OF MEDICINE. PubMed, which is searchable through NLM's Web site, also includes access to additional citations to selected life sciences journals not in MEDLINE, and links to other resources such as the full-text of articles at participating publishers' Web sites, NCBI's molecular biology databases, and PubMed Central.Periodicals as Topic: A publication issued at stated, more or less regular, intervals.Amyloid beta-Peptides: Peptides generated from AMYLOID BETA-PEPTIDES PRECURSOR. An amyloid fibrillar form of these peptides is the major component of amyloid plaques found in individuals with Alzheimer's disease and in aged individuals with trisomy 21 (DOWN SYNDROME). The peptide is found predominantly in the nervous system, but there have been reports of its presence in non-neural tissue.BooksPublishing: "The business or profession of the commercial production and issuance of literature" (Webster's 3d). It includes the publisher, publication processes, editing and editors. Production may be by conventional printing methods or by electronic publishing.MEDLINE: The premier bibliographic database of the NATIONAL LIBRARY OF MEDICINE. MEDLINE® (MEDLARS Online) is the primary subset of PUBMED and can be searched on NLM's Web site in PubMed or the NLM Gateway. MEDLINE references are indexed with MEDICAL SUBJECT HEADINGS (MeSH).