The short version of vaccine adjuvant fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-30. Anything still debated is marked as such rather than presented as settled.
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。
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。
Thymosin alpha-1 is a 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
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.
| Property | Value | Notes |
|---|---|---|
| 化学分类 | 线性肽 | 由28个氨基酸组成 |
| 分子量 | 约3108 Da | 合成版本一致 |
| 外观 | 白色至类白色粉末 | 冻干品 |
| 溶解度 | 易溶于水 | 微溶于有机溶剂 |
| 储存温度 | -20°C（冻干） | 溶解后2-8°C |
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.
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.
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.
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.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
239Pu is a key fissile component in nuclear weapons, due to its ease of fission and availability. Encasing the bomb's plutonium pit in a tamper (a layer of dense material) decreases the critical mass by reflecting escaping neutrons back into the plutonium core. This reduces the critical mass from 16 kg to 10 kg, which is a sphere with a diameter of about 10 centimeters (4 in). This critical mass is about a third of that for uranium-235. The Fat Man plutonium bombs used explosive compression of plutonium to obtain significantly higher density than normal, combined with a central neutron source to begin the reaction and increase efficiency. Thus only 6 kg of plutonium was needed for an explosive yield equivalent to 20 kilotons of TNT. Hypothetically, as little as 4 kg of plutonium—and maybe even less—could be used to make a single atomic bomb using very sophisticated assembly designs.
IP3, DAG, and Ca2+ are second messengers in the phosphoinositol pathway. The pathway begins with the binding of extracellular primary messengers such as epinephrine, acetylcholine, and hormones AGT, GnRH, GHRH, oxytocin, and TRH, to their respective receptors. Epinephrine binds to the α1 GTPase Protein Coupled Receptor (GPCR) and acetylcholine binds to M1 and M2 GPCR. Binding of a primary messenger to these receptors results in conformational change of the receptor. The α subunit, with the help of guanine nucleotide exchange factors (GEFS), releases GDP, and binds GTP, resulting in the dissociation of the subunit and subsequent activation. The activated α subunit activates phospholipase C, which hydrolyzes membrane bound phosphatidylinositol 4,5-bisphosphate (PIP2), resulting in the formation of secondary messengers diacylglycerol (DAG) and inositol-1,4,5-triphosphate (IP3). IP3 binds to calcium pumps on ER, transporting Ca2+, another second messenger, into the cytoplasm. Ca2+ ultimately binds to many proteins, activating a cascade of enzymatic pathways.
== History == 1. FC Lokomotive Leipzig claims to be the successor to the VfB Leipzig and SC Sportbrüder Leipzig teams, established in 1896 and 1893, respectively, and therefore, one of the oldest clubs of the German Football Association. However, they are not nominal successors. In 2018, 1. FC Lokomotive announced a merger with the formally extant but dormant VfB Leipzig in order to be entitled to the forerunner's titles. Due to the significant breaks and turmoil in the club's history, especially during the post-World War II era, their exact establishment date remains a source of contention.
Sources: en.wikipedia.org
== Causes == FOP is caused by an autosomal dominant allele on chromosome 2q23-24. The allele has variable expressivity, but complete penetrance. Most cases are caused by spontaneous mutation in the gametes; most people with FOP cannot or choose not to have children. A similar but less catastrophic disease is fibrous dysplasia, which is caused by a post-zygotic mutation. A mutation in the gene ACVR1 (also known as activin-like kinase 2 (ALK2)) is responsible for the disease. ACVR1 encodes activin receptor type-1, a BMP type-1 receptor. The mutation causes substitution of codon 206 from arginine to histidine in the ACVR1 protein. This substitution causes abnormal activation of ACVR1, leading to the transformation of connective tissue and muscle tissue into a secondary skeleton. This causes endothelial cells to transform to mesenchymal stem cells and then to bone. Normally, the ACVR1 gene encodes the activin receptor type-1 transmembrane kinase that bind BMP receptors (Type I BMPR and Type II BMPR) for chondrogenesis signaling. BMPs belong to a superfamily of proteins known as Transforming growth factor-beta (TGF-β) proteins. The binding of ACVR1 protein to BMP receptors start a signaling cascade that is crucial for inducing endochondral bone formation during development, as well as, skeletal and tissue homeostasis.
== Signs and symptoms == Generally, the majority of individuals with creatine transporter defect express the following symptoms with varying levels of severity: developmental delay and regression, intellectual disability, and abnormalities in expressive and cognitive speech. However, several studies have shown a wider variety of symptoms including, but not limited to attention deficit and hyperactivity with impulsivity, myopathy, hypotonia, semantic-pragmatic language disorder, oral dyspraxia, extrapyramidal movement disorder, constipation, absent speech development, seizures, and epilepsy. Furthermore, symptoms can significantly vary between hemizygous males and heterozygous females, although, symptoms are generally more severe in hemizygous males. Hemizygous males more commonly express seizures, growth deficiency, severe intellectual disability, and severe expressive language impairment. Heterozygous females more commonly express mild intellectual disability, impairments to confrontational naming and verbal memory, and learning and behavior problems.
==== E-I balance as crucial for visual cortex function ==== By computational modeling, Sur’s group proposed that a key feature of visual cortex networks - local and long-range connections between excitatory neurons critically balanced by inhibition - is essential for explaining feature-selective responses. They demonstrated that inhibition and excitation are exquisitely tuned across cortical sites, as demonstrated by imaging and intracellular recordings.
Sources: en.wikipedia.org
== Cost == In Canada, PET scan funding varies by province. In Ontario, as of October 2025, there is no charge to the patient for any PET scans funded as part of the PET Scans Ontario Program. The program funds routine PET services for indications where sufficient evidence exists that the scan benefits the patient and offers advantages over other imaging tests. In the United States, PET scan costs vary significantly by location, facility type, and insurance status. According to Medicare's 2026 payment data, a whole-body PET scan has a national average total cost of $872, with the patient paying approximately $174 after Medicare coverage. In the United Kingdom, the National Health Service provides PET-CT scans free at point of use for eligible patients. In Australia, Medicare subsidies are available for eligible PET services.
In 1990, the USDA's Food Safety and Inspection Service (FSIS) approved the use of the technology for manufacturing finely textured meat. At the time of its approval, the FSIS called the remaining product "meat", although one FSIS microbiologist dissented, arguing it contained both muscle and connective tissue. In 1994, in response to public health concerns over pathogenic E. coli in beef, the founder of BPI, Eldon Roth, began work on the "pH Enhancement System", which disinfects meat using injected anhydrous ammonia in gaseous form, rapid freezing to 28 °F (−2 °C), and mechanical stress. In 2001, the FSIS approved the gaseous disinfection system as an intermediate step before the roller press freezer, and approved the disinfected product for human consumption, as an additive. The FSIS agreed with BPI's suggestion that ammonia was a "processing agent" which did not need to be listed on labels as an ingredient. FSIS microbiologists Carl Custer and Gerald Zirnstein stated that they argued against the product's approval for human consumption, saying that it was not "meat" but actually "salvage", and that the USDA should seek independent verification of its safety, but they were overruled. In 2003, BPI commissioned a study of the effectiveness and safety of the disinfection process; the Iowa State University researchers found no safety concern in the product or in ground beef containing it. The term "pink slime", a reference to the product's "distinctive look", was coined in 2002 by Zirnstein in an internal FSIS e-mail.
=== Physiology === Rhabdomyolysis causes the myosin and actin to degenerate into smaller proteins that travel into the circulatory system. The body reacts by increasing intracellular swelling to the injured tissue to send repair cells to the area. This allows creatine kinase and myoglobin to be flushed from the tissue where it travels in the blood until reaching the kidneys. In addition to the proteins released, large quantities of ions such as intracellular potassium, sodium, and chloride find their way into the circulatory system. Intracellular potassium ion has deleterious effects on the heart's ability to generate action potentials leading to cardiac arrhythmias. Consequently, this can affect peripheral and central perfusion which in turn can affect all major organ systems in the body. When the protein reaches the kidneys it causes a strain on the anatomical structures reducing its effectiveness as a filter for the body. The protein acts as a dam as it forms into tight aggregates when it enters the renal tubules. In addition, the increased intracellular calcium has greater time to bind due to the blockage allowing for renal calculi to form. As a result this causes urine output to decrease allowing for the uric acid to build up inside the organ. The increased acid concentration allows the iron from the aggregate protein to be released into the surrounding renal tissue. Iron then strips away molecular bonds of the surrounding tissue which eventually will lead to kidney failure if the tissue damage is too great.
In 1912, the first deposit of distinct, single-crystal turquoise was discovered at Lynch Station in Campbell County, Virginia. The crystals, forming a druse over the mother rock, are very small; 1 mm (0.04 in) is considered large. Until the 1980s Virginia was widely thought to be the only source of distinct crystals; there are now at least 27 other localities. In an attempt to recoup profits and meet demand, some American turquoise is treated or enhanced to a certain degree. These treatments include innocuous waxing and more controversial procedures, such as dyeing and impregnation (see Treatments). There are some American mines which produce materials of high enough quality that no treatment or alterations are required. Any such treatments which have been performed should be disclosed to the buyer on sale of the material.
Sources: en.wikipedia.org
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。
天然胸腺素α1主要从胸腺组织提取，也可在脾脏和淋巴结中检出。目前研究和临床使用的多为化学合成版本，不再依赖动物组织。
胸腺素组分5是牛胸腺提取物的粗组分，包含多种肽。胸腺素α1是其中一种被纯化和表征的单一肽，具有明确的28个氨基酸序列。
It corresponds to the first 28 amino acids of thymosin beta-4, a larger protein found in many tissues. The fragment is acetylated at its N-terminus and is produced synthetically for research and pharmaceutical use. Synthetic and natural forms share the same sequence.