If you have been reading about counter-ion 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 2026-07-21. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
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。
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
Identity and purity are normally assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities and truncation products. Mass spectrometry confirms molecular mass and detects modifications such as deamidation or oxidation. Amino acid analysis and peptide mapping provide additional sequence-level confirmation. For research material, a certificate of analysis typically reports these results together with water content and counter-ion identity, since the lyophilized powder is often supplied as an acetate or trifluoroacetate salt.
| 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.
Laboratory supplies of the peptide usually arrive as a lyophilized powder in sealed vials. The powder is hygroscopic, so a vial should be allowed to reach room temperature before it is opened to prevent condensation on the contents. Weighing and transfer are best performed in a low-humidity environment with clean tools. Once dissolved, the solution should be mixed gently rather than vortexed, because foaming and shear can reduce recovery of the peptide.
Storage recommendations center on low temperature, dryness, and protection from repeated freezing and thawing. The intact powder is commonly held at 20 degrees below zero Celsius or colder, while a working solution is divided into single-use aliquots to limit freeze-thaw cycles. Buffered saline or phosphate-buffered saline at neutral pH is frequently used as a diluent. Light sensitivity is not well documented, yet amber vials or foil wrapping are common practice for long-term storage of peptide stocks.
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.
Other viruses have been implicated in its etiology, including cytomegalovirus, rubella virus, rotavirus, mumps virus, and SARS-CoV-2. Maternal infection during pregnancy has been associated with the development type 1 diabetes in the offspring; these studies implicated maternal infections with enteroviruses, cytomegalovirus and rubella virus.
=== Vaccinations === People with RA have an increased risk of infections and mortality, and recommended vaccinations can reduce these risks. The inactivated influenza vaccine should be received annually. The pneumococcal vaccine should be administered twice for people under the age 65 and once for those over 65. Lastly, the live-attenuated zoster vaccine should be administered once after the age 60, but is not recommended in people on a tumor necrosis factor alpha blocker.
Following the deaths of children in China from powdered milk in 2008, the Joint Research Centre (JRC) of the European Commission in Belgium set up a website about methods to detect melamine. In May 2009, the JRC published the results of a study that benchmarked the ability of labs around the world to accurately measure melamine in food. The study concluded that the majority of labs can effectively detect melamine in food. In October 2008, the U.S. Food and Drug Administration (FDA) issued new methods for the analysis of melamine and cyanuric acid in infant formulations in the Laboratory Information Bulletin No 4421. Similar recommendations have been issued by other authorities, like the Japanese Ministry of Health, Labor and Welfare, both based on liquid chromatography – mass spectrometry (LC/MS) detection after hydrophilic interaction liquid chromatography (HILIC) separation. The existing methods for melamine determination using a triple quadrupole liquid chromatography – mass spectrometry (LC/MS) after solid phase extraction (SPE) are often complex and time-consuming. However, electrospray ionization methods coupled with mass spectrometry allow a rapid and direct analysis of samples with complex matrices: the native liquid samples are directly ionized under ambient conditions in their original solution. In December 2008, two new fast and inexpensive methods for detecting melamine in liquids have been published.
Sources: en.wikipedia.org
No human pathogens of comparable virulence have yet emerged from marine species. In 2024 aquaculture production was concentrated in Asia which accounted for around 89% of global aquatic animal aquaculture production, followed by Latin America and the Caribbean (3%), Europe (2%), Africa (2%), Northern America (0.4%) and Oceania (0.2%). The top five countries together produced 82% of the total output; China, Indonesia, India, Viet Nam and Bangladesh. Freshwater systems dominate aquaculture production of aquatic animals, accounting for 64 million tonnes (63%), compared to 38 million tonnes (37%) from marine and coastal systems. Biological control methods to manage parasites are already being used, such as cleaner fish (e.g. lumpsuckers and wrasse) to control sea lice populations in salmon farming. Models are being used to help with spatial planning and siting of fish farms in order to minimize impact.
Often, when British allies attempted military actions within several dozen miles or so of the sea, the Royal Navy would arrive, land troops and supplies, and aid the coalition's land forces in a concerted operation. Royal Navy ships even provided artillery support against French units when fighting strayed near enough to the coastline. The ability and quality of the land forces governed these operations. For example, when operating with inexperienced guerrilla forces in Spain, the Royal Navy sometimes failed to achieve its objectives because of the lack of manpower that the Navy's guerrilla allies had promised to supply.
Subcutaneous adipose tissue is also a source of mesenchymal stem cells and have demonstrated positive outcomes in terms of cardiovascular tissue remodeling. Mammal hearts also host naturally occurring cardiac stem cells which may be capable of differentiating themselves into cardiomyocytes, endothelial cells and cardiac fibroblasts. This self-regeneration capacity gives rise to alternatives to classical cellular therapies whereby administration of growth factors such as Thymosin β4 for cell activation and migration are solely necessary. Largely democratized in terms of population information, embryonic stem cells are known for their strong capacity for expansion and differentiation into cardiomyocytes, endothelial cells and cardiac fibroblasts. However, if non autologous, immunosuppression therapy is associated with such treatment. Hence, research has been focused on induced pluripotent stem cells (iPSCs) from somatic human tissue. Further to cell and necessary relevant growth factor selection, cell delivery is an important issue. Indeed, the intracoronary route is the most straightforward cell delivery route as associated with intramyocardial cellular retention; retention rates are however low, i.e. exceed 10%. Washed off cells reach other organs or die, which can be an issue at the time of prepare ICH module 8. Other alternative injection routes have been studied, namely injection via sternotomy, endomyocardial and intracoronary routes.
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。
Dry lyophilized powder tolerates short ambient exposure during handling and shipping. Long-term room-temperature storage is not recommended because moisture uptake and slow degradation can occur over months. Storage at minus twenty degrees Celsius is the common practice for extended periods.