If you have been reading about 免疫组织 and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-01-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white lyophilized powder | Visual description varies by batch |
| Solubility | Freely soluble in water | Aqueous buffers are commonly used |
| Typical storage temperature | -20 °C or below for powder | Reconstituted liquid kept at 2-8 °C short term |
| Purity method | Reversed-phase HPLC | Value derived from peak area integration |
| Identity method | Mass spectrometry | Confirms mass and sequence integrity |
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Results across trials have been mixed, and several studies were small or conducted under differing protocols. Regulatory status varies by country, and the compound is not approved in every jurisdiction where it is studied. Evidence for any single indication should be read with attention to sample size and endpoint choice.
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
20世纪70年代，研究者从胸腺提取物中纯化出多种小肽，Tα1是其中被较早表征的一种。最初的制备依赖组织匀浆和层析步骤，产量低且成分复杂。随着固相肽合成技术成熟，实验室和工业界能够生产与天然序列一致的合成版本。合成肽的纯度可达95%以上，并可通过反相高效液相色谱和质谱进行鉴定。这一转变使研究不再依赖动物胸腺来源。
Thymosin alpha 1 is a short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
GeV, predicting a longer proton lifetime. However, SUSY also introduces dimension 5 operators that can contribute to proton decay with much shorter decay times. To suppress these contributions extra symmetries are invoked, with the result that decays to quarks and leptons in other generation than (u, d, e,
In other words, short-term high concentrations and long-term low concentrations of estradiol appear to have the same degree of effect in terms of genomic estrogenic signaling, at least in terms of breast cell proliferation over a 24-hour period. On the other hand, non-genomic actions of estradiol, such as signaling through membrane estrogen receptors like the GPER, may be reduced with short-term high concentrations of estradiol relative to more sustained levels. For instance, although daily intranasal administration of estradiol is associated with comparable clinical effectiveness (e.g., for hot flashes) relative to longer acting routes of estradiol administration in postmenopausal women, it is also associated with significantly lower rates of breast tension (tenderness and enlargement) relative to longer acting estradiol routes, and this is thought to reflect comparatively diminished non-genomic signaling.
Fermentation is a type of anaerobic metabolism that harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic molecules, such as glucose or other sugars, are catabolized and their electrons are transferred to other organic molecules (cofactors, coenzymes, etc.). Anaerobic glycolysis is a related term used to describe the occurrence of fermentation in organisms (usually multicellular organisms such as animals) when aerobic respiration cannot keep up with the ATP demand, due to insufficient oxygen supply or anaerobic conditions. Fermentation is important in several areas of human society. Humans have used fermentation in the production and preservation of food for 13,000 years. It has been associated with health benefits, unique flavor profiles, and making products have better texture. Humans and their livestock also benefit from fermentation from the microbes in the gut that release end products that are subsequently used by the host for energy. Perhaps the most commonly known use for fermentation is at an industrial level to produce commodity chemicals, such as ethanol and lactate. Ethanol is used in a variety of alcoholic beverages (beers, wine, and spirits) while lactate can be neutralized to lactic acid and be used for food preservation, as a curing agent, or as a flavoring agent. This complex metabolism utilizes a wide variety of substrates and can form nearly 300 different combinations of end products. Fermentation occurs in both prokaryotes and eukaryotes.
Potassium, in the form of potassium chloride is used as a medication to treat and prevent low blood potassium. Low blood potassium may occur due to vomiting, diarrhea, or certain medications. It is given by slow injection into a vein or by mouth.
== Valence == Vaccines may be monovalent (also called univalent) or multivalent (also called polyvalent). A monovalent vaccine is designed to immunize against a single antigen or single microorganism. A multivalent or polyvalent vaccine is designed to immunize against two or more strains of the same microorganism, or against two or more microorganisms. The valency of a multivalent vaccine may be denoted with a Greek or Latin prefix (e.g., bivalent, trivalent, or tetravalent/quadrivalent). In certain cases, a monovalent vaccine may be preferable for rapidly developing a strong immune response.
Sources: en.wikipedia.org
=== SELEX === Conventional (up to 1016 different oligonucleotides) existing molecule library serves as a starting point for the subsequent SELEX process. Selection, separation, and amplification using the mirror image of the target molecule is performed.
The GoldSrc engine was also used for a variety of third-party games and modifications not directly developed by Valve. Rewolf Software used the engine for the game Gunman Chronicles in 2000, and the PC version of James Bond 007: Nightfire was developed by Gearbox Software using a modified version of GoldSrc in 2002. Unofficial, community-made modifications of GoldSrc have also been produced. Notable games include Natural Selection, Cry of Fear and Sven Co-op, with Valve's Team Fortress Classic, Counter-Strike, and Day of Defeat all being based on GoldSrc mods of the same names. Sven Co-op have since been released for free as a standalone game on Steam, which use a licensed derivative of the engine with their own customizations. The Xash3D project and forks use Quake engine source code in part, as well as the Half-Life SDK, to recreate GoldSrc and run its various mods on different platforms. The FreeHL and FreeCS ports also utilize QuakeWorld code as well as clean-room reverse engineering.
where δ2HA is the delta value of pool A relative to VSMOW. As many delta values do not vary greatly from one another the α value is often very close to unity. A related measure called epsilon (ε) is often used which is given simply by:
== Terminology == Although "transition matrix" is often used interchangeably with "substitution matrix" in fields other than bioinformatics, the former term is problematic in bioinformatics. With regards to nucleotide substitutions, "transition" is also used to indicate those substitutions that are between the two-ring purines (A → G and G → A) or are between the one-ring pyrimidines (C → T and T → C). Because these substitutions do not require a change in the number of rings, they occur more frequently than the other substitutions. "Transversion" is the term used to indicate the slower-rate substitutions that change a purine to a pyrimidine or vice versa (A ↔ C, A ↔ T, G ↔ C, and G ↔ T).
Sources: en.wikipedia.org
Christopher Richard Stein (born 4 January 1947) is an English celebrity chef, restaurateur, writer and television presenter. Along with business partner and first wife Jill Stein, he runs the Stein hotel and restaurant business in the UK. The business has a number of renowned restaurants, shops and hotels in Padstow along with other restaurants in Winchester and Barnes. He is the head chef and a co-owner of the Rick Stein at Bannisters restaurants in Mollymook and Port Stephens in Australia, with his second wife, Sarah. He writes cookery books and has presented numerous cookery series for the BBC.
A synergy of two mechanisms, stabilization of closed conformation and exclusion of catalytic water by the tightly juxtaposed GAMEN loop was proposed as the mechanism of inhibition. Moreover, M1 aminopeptidases use a tyrosine residue in the active site to stabilize the transition state. In the case of IRAP, the catalytic Tyr549 is found in different orientations in the open and closed conformations. For example, in the case of phosphinic pseudopeptide inhibitors, which mimic the transition state of peptide substrates, Tyr549 changes orientation upon ligand binding to interact with one of the oxygen atoms of the phosphinic group, which is equivalent to the oxygen atoms of the substrate in the transition state.
One exception is that thyroid hormones may aggravate heart conditions, especially in older patients; therefore, physicians may start these patients on a lower dose and work up to a larger one to avoid the risk of a heart attack.
Sources: en.wikipedia.org
Cold storage slows the chemical degradation reactions that occur in solution. Lyophilized powder is more stable than reconstituted liquid and tolerates longer storage periods. Repeated temperature cycling should still be avoided because it can drive aggregation and loss of material.
Mass spectrometry is the standard confirmation of molecular mass and acetylation state. Chromatography establishes purity but does not identify the molecule on its own. The two techniques are normally applied together during verification.
No, because the reported value reflects the detection method and wavelength used, which vary between laboratories. A number stated without method details cannot be compared directly with another supplier's figure. Requesting the chromatogram and the method conditions is a common way to interpret it.
Trials differ in patient population, dose schedule, background treatment, and the endpoints used to judge success. Many are small and single-center, so random variation can dominate the reported effects.