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Phytol
Phytol (florasol, phytosol) is an acyclic hydrogenated diterpene alcohol that is used as a precursor for the manufacture of synthetic forms of vitamin E and vitamin K1, as well as in the fragrance industry. Its other commercial uses include cosmetics, shampoos, toilet soaps, and detergents, as well as in some cannabis distillates as a diluent or for flavoring. It smells grassy and dominates the aroma of certain green teas. Its worldwide use has been estimated to be approximately 0.1–1.0 metric tons per year. Pharmacology Humans Refsum disease (also known as adult Refsum disease) is an autosomal recessive disorder that results in the accumulation of toxic stores of phytanic acid in tissues and frequently manifests as a variable combination of peripheral polyneuropathy, cerebellar ataxia, retinitis pigmentosa, anosmia, and hearing loss. Although humans cannot derive phytanic acid from chlorophyll, they can convert free phytol into phytanic acid. Thus, patients with Refsum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diterpene
Diterpenes are a class of terpenes composed of four isoprene units, often with the molecular formula C20H32. They are biosynthesized by plants, animals and fungi via the HMG-CoA reductase pathway, with geranylgeranyl pyrophosphate being a primary intermediate. Diterpenes form the basis for biologically important Chemical compound, compounds such as retinol, retinal, and phytol. Some diterpenes are known to be antimicrobial and anti-inflammatory. Structures As with most terpenes a huge number of potential structures exists, which may be broadly divided according to the number of rings present. Biosynthesis Diterpenes are derived from the addition of one Isopentenyl pyrophosphate, IPP unit to Farnesyl pyrophosphate, FPP to form geranylgeranyl pyrophosphate (GGPP). From GGPP, structural diversity is achieved mainly by two classes of enzymes; the diterpene synthases and Cytochrome P450, cytochromes P450. Several diterpenes are produced by plants and cyanobacteria. GGPP is also t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytanic Acid
Phytanic acid (or 3,7,11,15-tetramethyl hexadecanoic acid) is a branched-chain fatty acid that humans can obtain through the consumption of dairy products, ruminant animal fats, and certain fish. Western diets are estimated to provide 50–100 mg of phytanic acid per day. In a study conducted in Oxford, individuals who consumed meat had, on average, a 6.7-fold higher geometric mean plasma phytanic acid concentration than did vegans. Human pathology Unlike most fatty acids, phytanic acid cannot be metabolized by β-oxidation. Instead, it undergoes α-oxidation in the peroxisome, where it is converted into pristanic acid by the removal of one carbon. Pristanic acid can undergo several rounds of β-oxidation in the peroxisome to form medium chain fatty acids that can be converted to carbon dioxide and water in mitochondria. Individuals with adult Refsum disease, an autosomal recessive neurological disorder caused by mutations in the '' PHYH'' gene, have impaired α-oxidation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Median Lethal Dose
In toxicology, the median lethal dose, LD50 (abbreviation for " lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a given substance. The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indicative of higher toxicity. The term LD50 is generally attributed to John William Trevan. The test was created by J. W. Trevan in 1927. The term semilethal dose is occasionally used in the same sense, in particular with translations of foreign language text, but can also refer to a sublethal dose. LD50 is usually determined by tests on animals such as laboratory mice. In 2011, the U.S. Food and Drug Administration approved alternative methods to LD50 for testing the cosmetic drug botox without animal tests. Conventions The LD50 is usually expr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sprague Dawley
Laboratory rats or lab rats are strains of the rat subspecies '' Rattus norvegicus domestica'' (Domestic Norwegian rat) which are bred and kept for scientific research. While less commonly used for research than laboratory mice, rats have served as an important animal model for research in psychology and biomedical science, and "lab rat" is commonly used as an idiom for a test subject. Origins of rat breeding In 18th-century Europe, wild brown rats (''Rattus norvegicus'') ran rampant and this infestation fueled the industry of rat-catching. Rat-catchers would not only make money by trapping the rodents, but also by selling them for food or, more commonly, for rat-baiting. Rat-baiting was a popular sport, which involved filling a pit with rats and timing how long it took for a terrier to kill them all. Over time, breeding the rats for these contests may have produced color variations, notably the albino and hooded varieties. The first time one of these albino mutants was b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerosol
An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be generated from natural or Human impact on the environment, human causes. The term ''aerosol'' commonly refers to the mixture of particulates in air, and not to the particulate matter alone. Examples of natural aerosols are fog, mist or dust. Examples of human caused aerosols include particulate air pollutants, mist from the discharge at hydroelectric dams, irrigation mist, perfume from Spray nozzle, atomizers, smoke, dust, Pesticide, sprayed pesticides, and medical treatments for respiratory illnesses. Several types of atmospheric aerosol have a significant effect on Earth's climate: volcanic, desert dust, sea-salt, that originating from biogenic sources and human-made. Volcanic aerosol forms in the stratosphere after an eruption as droplets of sulfuric acid that can prevail for up to two years, and reflect sunlight, lowering tempera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tissue (biology)
In biology, tissue is an assembly of similar cells and their extracellular matrix from the same embryonic origin that together carry out a specific function. Tissues occupy a Biological organisation#Levels, biological organizational level between cell (biology), cells and a complete organ (biology), organ. Accordingly, organs are formed by the functional grouping together of multiple tissues. The English word "tissue" Morphological derivation, derives from the French word "", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology. Xavier Bichat is considered as the "Father of Histology". Plant histology is Studied Space Shuttle designs, studied in both plant anatomy and Plant physiology, physiology. The classical tools for studying tissues are the Microtome#Applications, paraffin block in which tissue is embedded and then sectioned, the staining, histological stain, and the Microscope, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung
The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their function in the respiratory system is to extract oxygen from the atmosphere and transfer it into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere, in a process of gas exchange. Respiration is driven by different muscular systems in different species. Mammals, reptiles and birds use their musculoskeletal systems to support and foster breathing. In early tetrapods, air was driven into the lungs by the pharyngeal muscles via buccal pumping, a mechanism still seen in amphibians. In humans, the primary muscle that drives breathing is the Thoracic diaphragm, diaphragm. The lungs also provide airflow that makes Animal communication#Auditory, vocalisation including speech possible. Humans have two lungs, a ri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Throat
In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the Human pharynx, pharynx and larynx. An important section of it is the epiglottis, separating the esophagus from the trachea (windpipe), preventing food and drinks being inhaled into the lungs. The throat contains various blood vessels, pharyngeal muscles, the adenoid, nasopharyngeal tonsil, the tonsils, the palatine uvula, the trachea, the esophagus, and the vocal cords. Mammal throats consist of two bones, the hyoid bone and the clavicle. The "throat" is sometimes thought to be synonymous for the Fauces (throat), fauces. It works with the mouth, ears and nose, as well as a number of other parts of the body. Its pharynx is connected to the mouth, allowing speech to occur, and food and liquid to pass down the throat. It is joined to the nose by the nasopharynx at the top of the throat, and to the ear by its Eustachian tube. The throat's trachea carries in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nose
A nose is a sensory organ and respiratory structure in vertebrates. It consists of a nasal cavity inside the head, and an external nose on the face. The external nose houses the nostrils, or nares, a pair of tubes providing airflow through the nose for Respiration (physiology), respiration. Where the nostrils pass through the nasal cavity they widen, are known as nasal fossae, and contain nasal concha, turbinates and olfactory mucosa. The nasal cavity also connects to the paranasal sinuses (dead-end air cavities for pressure buffering and humidification). From the nasal cavity, the nostrils continue into the pharynx, a switch track valve connecting the respiratory system, respiratory and digestive systems. In humans, the nose is located centrally on the face and serves as an alternative respiratory passage especially during suckling for infants. The protruding nose that is completely separate from the mouth part is a characteristic found only in theria, therian mammals. It has b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who is often regarded as one of the founders of modern pathology. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated digestion of cell components. In contrast, ''apoptosis'' is a naturally occurring programmed and targeted cause of cellular death. While apoptosis often provides beneficial effects to the organism, necrosis is almost always detrimental and can be fatal. Cellular death due to necrosis does not follow the apoptotic signal transduction pathway, but rather various receptors are activated and result in the loss of cell membrane integrity and an uncontrolled release of products of cell death into the extracellular space. This initiates an inflammatory response in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Hemorrhage
Pulmonary hemorrhage (or pulmonary haemorrhage) is an acute bleeding from the lung, from the upper respiratory tract and the trachea, and the pulmonary alveoli. When evident clinically, the condition is usually massive.Pulmonary Hemorrhage Intensive Care Nursery House Staff Manual. UCSF Children's Hospital at UCSF Medical Center. 2004:The Regents of the . Retrieved 2008-10-28. The onset of pulmonary hemorrhage is characterized by a cough productive of ( |
Chlorophyll
Chlorophyll is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words (, "pale green") and (, "leaf"). Chlorophyll allows plants to absorb energy from light. Those pigments are involved in oxygenic photosynthesis, as opposed to bacteriochlorophylls, related molecules found only in bacteria and involved in anoxygenic photosynthesis. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion. Conversely, it is a poor absorber of green and near-green portions of the spectrum. Hence chlorophyll-containing tissues appear green because green light, diffusively reflected by structures like cell walls, is less absorbed. Two types of chlorophyll exist in the photosystems of green plants: chlorophyll ''a'' and ''b''. History Chlorophyll was first isolated and named by Joseph Bienaimé Caventou and Pierre Joseph Pelletier in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
