免疫组织 raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-03-03 and is reviewed periodically as new material appears.
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.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
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.
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
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。
| Property | Value | Notes |
|---|---|---|
| Amino acid length | 28 residues | Single chain with an acetylated N-terminus |
| Molecular mass | Approximately 3,108 Da | Small shifts occur with counter-ion and water content |
| Isoelectric point | Around 3.5 | Low value follows from the many acidic residues |
| Parent molecule | N-terminal region of prothymosin alpha | Free circulating form in humans is not firmly established |
| Common synonyms | Thymalfasin; T alpha 1 | Older literature also uses the full spelled-out form |
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
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.
Thymosin alpha 1 is a short peptide first isolated from bovine thymus tissue in the early 1970s during fractionation work aimed at identifying factors that influence T cell development. It belongs to a family of acidic thymic peptides, and the original preparations contained several components that were later separated by chromatography. The compound is now produced synthetically rather than extracted from tissue, which removes batch variability tied to animal sourcing. Researchers describe it as an immunomodulatory peptide because laboratory studies show effects on several cell types of the innate and adaptive immune systems.
The molecule consists of 28 amino acid residues with an acetyl group attached to the N-terminal serine. Its sequence is acidic overall, with several glutamic and aspartic acid residues distributed along the chain and no cysteine, so disulfide bridges do not form. The peptide carries a net negative charge at physiological pH. Because the N-terminus is blocked, the intact molecule resists degradation by many aminopeptidases, which contributes to its stability in biological fluids.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids whose sequence matches the amino-terminal region of prothymosin alpha. The chain is acetylated at its first residue and contains one disulfide bridge between two cysteine residues, which folds the molecule into a compact loop. Its molecular formula, C129H215N33O55, corresponds to a monoisotopic mass of roughly 3,106 daltons. Material used in laboratories is made by solid-phase synthesis rather than isolated from animal tissue.
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
Thymosin alpha 1 is a synthetic 28-amino-acid peptide first isolated in 1966 from thymosin fraction 5, a bovine thymus extract. Its chain begins with an acetylated serine residue and ends with asparagine. The native peptide carries a molecular mass near 3,108 daltons. Researchers classify it as an immunomodulatory agent rather than a hormone with a single endocrine target. Early work framed it as a thymus-derived factor that supports T-cell maturation. The synthetic form used in research and clinical products matches the natural sequence.
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
Robert Emmet Finnigan (May 27, 1927 – August 14, 2022) was an American pioneer in the development of gas chromatography–mass spectrometry equipment (GC/MS). Finnigan founded the Scientific Instruments Division of Electronic Associates, Inc., producing the first commercial quadrupole mass spectrometer in 1964. He then formed Finnigan Instruments Corporation to combine a computer system with a quadrupole mass spectrometer and gas chromatograph. Finnigan's GC/MS/computer systems are used to detect and identify trace organic compounds, making them important instruments for the monitoring and protection of the environment. They were adopted by the United States Environmental Protection Agency as a standard instrument for monitoring water quality and were fundamental to the work of the EPA.
The vast majority of insulin used worldwide is biosynthetic recombinant human insulin or its analogues. Recently, another recombinant approach has been used by a pioneering group of Canadian researchers, using an easily grown safflower plant, for the production of much cheaper insulin. Recombinant insulin is produced either in yeast (usually Saccharomyces cerevisiae) or E. coli. In yeast, insulin may be engineered as a single-chain protein with a KexII endoprotease (a yeast homolog of PCI/PCII) site that separates the insulin A chain from a C-terminally truncated insulin B chain. A chemically synthesized C-terminal tail containing the missing threonine is then grafted onto insulin by reverse proteolysis using the inexpensive protease trypsin; typically the lysine on the C-terminal tail is protected with a chemical protecting group to prevent proteolysis. The ease of modular synthesis and the relative safety of modifications in that region accounts for common insulin analogs with C-terminal modifications (e.g. lispro, aspart, glulisine). The Genentech synthesis and completely chemical synthesis such as that by Bruce Merrifield are not preferred because the efficiency of recombining the two insulin chains is low, primarily due to competition with the precipitation of insulin B chain.
Two other 3,6 diesters of morphine invented in 1874–75 along with diamorphine, dibenzoylmorphine and acetylpropionylmorphine, were made as substitutes after it was outlawed in 1925 and, therefore, sold as the first "designer drugs" until they were outlawed by the League of Nations in 1930.
=== Chemical dating/ Total Pb dating === Chemical dating requires measuring the elemental abundances of U, Th and Pb but not isotopes. U-Th-total Pb dating, also known as electron microprobe U–Th–Pb dating, measures the elemental abundances of the three elements by an electron microprobe, and calculates the age (t) by the below equation.
Regorafenib is administered orally for the treatment of colorectal cancer, gastrointestinal stromal cancer and hepatocellular carcinoma. Nintedanib is used for the treatment of idiopathic pulmonary fibrosis. Tests for liver function have to be made to modify doses before the therapy can start. Apatinib is used for the treatment of advanced gastric cancer. It is often diagnosed in late stages because there are no early signs or symptoms.
Sources: en.wikipedia.org
278113 → 274111Rg + α → 270109Mt + α → 266107Bh + α → 262105Db + α → 258103Lr + α → 254101Md + α This decay chain differed from the previous observations at Riken mainly in the decay mode of 262Db, which was previously observed to undergo spontaneous fission, but in this case instead alpha decayed; the alpha decay of 262Db to 258Lr is well-known. The team calculated the probability of accidental coincidence to be 10−28, or totally negligible. The resulting 254Md atom then underwent electron capture to 254Fm, which underwent the seventh alpha decay in the chain to the long-lived 250Cf, which has a half-life of around thirteen years. The 249Bk + 48Ca experiment was repeated at the JINR in 2012 and 2013 with consistent results, and again at the GSI in 2014. In August 2013, a team of researchers at Lund University in Lund, Sweden, and at the GSI announced that they had repeated the 2003 243Am + 48Ca experiment, confirming the findings of the JINR–LLNL collaboration. The same year, the 2003 experiment had been repeated at the JINR, now also creating the isotope 289115 that could serve as a cross-bombardment for confirming their discovery of the element 117 isotope 293117, as well as its daughter 285113 as part of its decay chain. Confirmation of 288115 and its daughters was published by the team at the LBNL in August 2015.
== Origin == There are conflicting stories about the dessert's origin. Some claim that it was first served during the 1893 Chicago World's Fair, where the ice cream sundae was also invented. Though in 1894, a Philadelphia company was given credit for its invention describing: "A small, solid [cake] of the ice cream is enveloped in a thin sheet of pie crust and then dipped into boiling lard or butter to cook the outside to a crisp. Served immediately, the ice cream is found to be as solidly frozen as it was first prepared." It may be derived in part from Baked Alaska, originating earlier in the 19th century, which puts ice cream under a quickly broiled meringue.
The Wagler's pit viper is sexually dimorphic: the females grow to approximately 1 m (39+1⁄4 in) in total length (including tail), their bodies being black with yellow stripes. Males, on the other hand, typically do not exceed 75 cm (29+1⁄2 in). Males have large triangular-shaped heads, with relatively thin green bodies. They are almost entirely arboreal, and their tails are prehensile to aid in climbing. They are found in a wide variety of colors and patterns, often referred to as "phases". In the past, some researchers classified the different phases as subspecies. The phases vary greatly from having a black or brown coloration as a base, with orange and yellow banding, to others having a light green as the base color, with yellow or orange banding, and many variations therein.
In 1738, Swiss physicist and mathematician Daniel Bernoulli postulated that the pressure of gases and heat were both caused by the underlying motion of molecules. Using his model he could predict the ideal gas law at constant temperature and suggested that the temperature was proportional to the velocity of the particles. This success was not followed up, in part because the then new tools of calculus allowed more progress using continuous models for gases. James Clerk Maxwell, a vocal proponent of atomism, revived the kinetic theory in 1860 and 1867. His key insight was that the velocity of particles in a gas would vary around an average value, introducing the concept of a distribution function. In the late 1800s, Ludwig Boltzmann used atomic models to apply kinetic theory to thermodynamics especially the second law relating to entropy. Boltzmann defended the atomistic hypothesis against major detractors from the time like Ernst Mach or energeticists like Wilhelm Ostwald, who considered that energy was the elementary quantity of reality. However an atomic model was not essential for the development of theory of thermodynamics. This became clear when Josiah Willard Gibbs introduced statistical mechanics in his 1902 book Elementary Principles in Statistical Mechanics. His logical and formal development of a new approach specifically avoided requiring an atomic hypothesis. Albert Einstein independently developed an approach similar to Gibbs, but with a completely different aim: Einstein set out to find a way to verify the atomic hypothesis through the kinetic theory.
Sources: en.wikipedia.org
South Africa The model remained in production in South Africa, as an entry-level model until 2003. It was also sold there as the "Midge", the "Sting", and as the "Ford Tonic". A locally designed pickup based on the Familia front end, called the Rustler was also produced, and sold as the "Ford Bantam". From 1991 to 1994 Samcor also produced and sold the 323 with the 2.0 L 16-valve DOHC FE engine from the Mazda 626 and badged it "200i". Along with the 2.0 L 16-valve DOHC engine there were upgrades to the suspension and braking system. Still, the 1.6-litre GT-Ae homologation car was more powerful. This South African built model was also sold in Australia between 1989 and 1991 with minor changes, the most noticeable one being the front indicators having a clear color rather than the normal amber. These models were labeled BF as opposed to the next generation's BG.
== Scientific contributions == Potassium channels demonstrate a seemingly counterintuitive activity: they permit the passage of potassium ions, whereas they do not allow the passage of the much smaller sodium ions. Before MacKinnon's work, the detailed molecular architecture of potassium channels and the means by which they conduct ions were only generally known and indirectly inferred. In 1998, despite barriers to the structural study of integral membrane proteins that had thwarted most attempts for decades, MacKinnon and colleagues determined the three-dimensional molecular structure of a potassium channel from an actinobacterium, Streptomyces lividans, utilizing X-ray crystallography. With this structure and other biochemical experiments, MacKinnon and colleagues were able to explain the exact mechanism by which potassium channel selectivity occurs. His prize-winning research was conducted primarily at the Cornell High Energy Synchrotron Source (CHESS) of Cornell University, and at the National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory. MacKinnon was elected to the American Philosophical Society in 2005. In 2007 he became a foreign member of the Royal Netherlands Academy of Arts and Sciences.
== Overview of AIDA physiological model == AIDA has been described in detail in the medical / scientific / computing / diabetes literature. It incorporates a compartmental model that describes glucose-insulin interaction in people completely lacking endogenous insulin secretion — i.e. insulin-dependent patients with type 1 diabetes mellitus. The AIDA model contains a single extra-cellular glucose compartment into which glucose enters via both absorption from the intestine and glucose production from the liver. The model also contains separate compartments for plasma and 'active' insulin, the latter being responsible for glycemic control while insulin is removed from the former by liver degradation. Full details of the AIDA model are accessible from within the AIDA software package, and can be viewed and printed separately via the AIDA website.
Sources: en.wikipedia.org
It is usually described as an immunomodulatory peptide rather than a classic circulating hormone. No endocrine gland is known to release it as a primary secretory product, and its measured presence in blood is not firmly established.
Prothymosin alpha is a much larger acidic protein, roughly 111 to 113 residues long, and the thymosin alpha-1 sequence matches its N-terminal region. The small peptide is therefore best understood as a fragment of that parent protein rather than a separate gene product.
Trials and clinical reports have examined chronic hepatitis B and C, use as a vaccine adjuvant, and supportive treatment in some immunodeficiency and oncology settings. Results vary by indication, and regulatory approval differs between countries.
它不是经典的内分泌激素，而是一种免疫调节肽。其作用主要通过局部免疫细胞间的信号传递实现，而非经血液循环作用于远隔器官。