A practical reference on 免疫组织: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-02-27. Anything still debated is marked as such rather than presented as settled.
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.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography, which separates the peptide from closely related impurities and from truncated or oxidized variants. Mass spectrometry supplies the molecular mass and confirms the expected sequence length, while amino acid analysis can be used to check composition. Because the molecule has no chromophore beyond the peptide backbone, ultraviolet detection is typically performed at a low wavelength, where baseline interference from solvents and buffers is a practical concern. Water content and counter-ion content are often reported alongside purity.
Practical handling focuses on limiting adsorption and contamination. The peptide dissolves readily in water, and dilute solutions tend to adhere to plastic and glass surfaces, so an inert carrier protein or a defined buffer can reduce losses in laboratory work. Workers also record the counter-ion form, since an acetate or trifluoroacetate salt changes the mass balance of the weighed powder. Documentation of lot number, purity value, and storage history supports reproducibility when results from different laboratories are compared.
Lyophilized material is generally held at reduced temperature to slow degradation, and storage at minus twenty degrees Celsius or lower is common practice for long-term retention. Short-term working portions are often kept between two and eight degrees Celsius. Once dissolved, the peptide is less stable than the dry powder, and repeated freeze-thaw cycles are associated with loss of material and with aggregate formation. Vials are usually allowed to reach room temperature before opening so that condensation does not introduce moisture, and solutions are protected from light where practical.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | ≈3,108 Da | Synthetic 28-residue peptide |
| Amino acid count | 28 | N-terminal serine carries an acetyl group |
| Appearance | White to off-white powder | Lyophilized solid |
| Water solubility | Freely soluble | Dissolves in aqueous buffer |
| Common synonyms | Thymalfasin; Tα1 | Thymalfasin is the international nonproprietary name |
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。
Quality control for thymosin alpha-1 focuses on identity, purity, and potency. Identity is confirmed by mass spectrometry and amino acid analysis, while purity is assessed by chromatography with limits on related substances and residual solvents. Potency assays may use cell-based immune readouts, but these are not standardized across laboratories. Regulatory status differs by jurisdiction; no product is approved in the United States for clinical use, whereas some other countries register injectable forms for specific indications.
Quantifying thymosin alpha-1 in a sample usually relies on reverse-phase high-performance liquid chromatography. The peptide lacks strong chromophores, so detection often occurs at 214 nm, where the peptide backbone absorbs. Mass spectrometry provides confirmatory identification and can detect sequence variants or truncations. Immunoassays have been used in biological matrices, but they may cross-react with related fragments. For purity assessment, chromatographic peak area gives the main component percentage, while mass accuracy verifies molecular identity.
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.
Like most short peptides, thymosin alpha-1 is susceptible to hydrolysis under strongly acidic or basic conditions and to oxidation when exposed to air over long periods. The acetylated amino terminus blocks one common degradation route, which contributes to the molecule's relative robustness in solution. Lyophilized material generally retains potency for extended periods when kept cold and dry. Once reconstituted, aqueous solutions are less stable and are typically used within a defined window rather than held indefinitely at ambient temperature.
Routine handling calls for storage of the lyophilized powder at refrigerated temperatures, away from light, in a sealed container. Working solutions are often prepared in sterile water or buffer and kept cold between uses. Repeated freeze-thaw cycles are generally avoided because they can promote aggregation and loss of material. Laboratories usually record lot number, reconstitution date, and storage conditions so that any change in behavior can be traced to a specific preparation.
=== Government and NGO reports === National Drug Threat Assessment 2009 from the United States Department of Justice War On Drugs: Legislation in the 108th Congress and Related Developments, a 2003 report from the Congressional Research Service via the State Department website The Report of the Canadian Government Commission of Inquiry into the Non-Medical Use of Drugs – 1972 Drug Enforcement Administration (2017), Drugs of abuse: A DEA resource guide (PDF) (2017 ed.), Washington, D.C.: Author, archived from the original (PDF) on December 3, 2016, retrieved January 23, 2018 Revealing the missing link to Climate Justice: Drug Policy, a 2023 report from the International Coalition on Drug Policy Reform and Environmental Justice
== Further reading == Kishi, K.; Okabe, K.; Shimizu, R.; Kubota, Y. (2012). "Fetal Skin Possesses the Ability to Regenerate Completely: Complete Regeneration of Skin". The Keio Journal of Medicine. 61 (4): 101–108. doi:10.2302/kjm.2011-0002-ir. PMID 23324304.
BeaverTails pastry (or Queues de Castor pâtisserie in Quebec) is a chain of pastry stands operated by BeaverTails Canada Inc. The chain's namesake product is a line of fried dough pastries, individually hand-stretched to resemble a beaver's tail. The chain began in Ottawa and now has franchises and licensees in six countries: Canada (Atlantic Canada, Ontario, Alberta, Manitoba, British Columbia and Quebec), the United States, Japan, France, U.A.E., and Mexico.
Article 12 protects the interests of pharmaceutical and chemical companies by requiring the Board to take into account the "extent, importance and diversity of the licit use of the substance, and the possibility and ease of using alternate substances both for licit purposes and for the illicit manufacture of narcotic drugs or psychotropic substances." Control of amphetamine-type stimulant precursors has become a major UN priority.
Sources: en.wikipedia.org
== External links == International Chemical Safety Card 0457 NIOSH Pocket Guide to Chemical Hazards. "#0226". National Institute for Occupational Safety and Health (NIOSH). Concise International Chemical Assessment Document 31: N,N-Dimethylformamide
Secondary-ion mass spectrometry (SIMS) is a technique used to analyze the composition of solid surfaces and thin films by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing ejected secondary ions. The mass/charge ratios of these secondary ions are measured with a mass spectrometer to determine the elemental, isotopic, or molecular composition of the surface to a depth of 1 to 2 nm. Due to the large variation in ionization probabilities among elements sputtered from different materials, comparison against well-calibrated standards is necessary to achieve accurate quantitative results. SIMS is the most sensitive elemental surface analysis technique, with elemental detection limits ranging from parts per million to parts per billion.
The H+ gradient can be eliminated either with H+ ionophores (protonophores) such as nigericin or monensin or by inhibiting the V-ATPase that generates the H+ gradient with compounds such as bafilomycin A1 or concanamycin.
The mechanism of the Hofmeister series is not entirely clear, but seems to result mainly from effects on the solvent at higher salt concentrations (> 100 mM). Early members of the series increase solvent surface tension and decrease the solubility of nonpolar molecules (salt out); in effect, they strengthen the hydrophobic interaction. By contrast, later salts in the series increase the solubility of nonpolar molecules (salt in) and decrease the order in water; in effect, they weaken the hydrophobic effect. However, these salts also interact directly with proteins (which are charged and have strong dipole moments) and may even bind specifically (e.g., phosphate and sulfate binding to ribonuclease A). Ions that have a strong salting in effect such as I− and SCN− are strong denaturants, because they salt in the peptide group, and thus interact much more strongly with the unfolded form of a protein than with its native form. Consequently, they pull the unfolding reaction. Moreover, they may have direct interactions with some standard hydrophobic molecules, e.g., benzene. A quantum chemical investigation suggests an electrostatic origin of the Hofmeister series, which appears to quantify this qualitative series (at least for anions).
In the 1970s, bodybuilding had major publicity thanks to the appearance of Arnold Schwarzenegger, Franco Columbu, Lou Ferrigno, Mike Mentzer and others in the 1977 docudrama Pumping Iron. By this time, the IFBB dominated the competitive bodybuilding landscape and the Amateur Athletic Union (AAU) took a back seat. The National Physique Committee (NPC) was formed in 1981 by Jim Manion, who had just stepped down as chairman of the AAU Physique Committee. The NPC has gone on to become the most successful bodybuilding organization in the United States and is the amateur division of the IFBB. The late 1980s and early 1990s saw the decline of AAU-sponsored bodybuilding contests. In 1999, the AAU voted to discontinue its bodybuilding events.
Sources: en.wikipedia.org
The Doobie Brothers are an American rock band formed in San Jose, California, in 1970. Known for their flexibility in performing across numerous genres and their vocal harmonies, the band has been active for over five decades, with their greatest success taking place in the 1970s. The group's current lineup consists of founding members Tom Johnston (guitars, keyboards, harmonica, vocals) and Patrick Simmons (guitars, banjo, recorder, vocals), alongside Michael McDonald (keyboards, synthesizers, mandolin, vocals) and John McFee (guitars, pedal steel guitar, mandolin, banjo, violin, cello, harmonica, vocals), and touring musicians including John Cowan (bass, vocals), Marc Russo (saxophones), Ed Toth (drums), and Marc Quiñones (percussion, backing vocals). Long-serving former members include guitarist Jeff "Skunk" Baxter, bassist Tiran Porter, and drummers John Hartman, Michael Hossack, and Keith Knudsen. Johnston provided the lead vocals from 1970 to 1975, when they featured a mainstream rock sound with elements of folk, country and R&B. McDonald joined the band in 1975 as a keyboardist and additional lead vocalist, to give some relief to Johnston, who was suffering health problems at the time. McDonald's interest in soul music introduced a new sound to the band. Johnston, Simmons, Porter, and McDonald performed together as lead vocalists for one album, Takin' It to the Streets, before Johnston left in 1977.
Copper(II) sulfate remains "the most effective algicidal treatment". A related traditional use is the Bordeaux mixture, used to control fungus on fruits. Hydrated lime, as a biocide, is allowed in the production of organic foods.
=== DCLRE1C mutation === DCLRE1C "Artemis" is a gene required for DNA repair and V(D)J recombination. A recessive loss-of-function mutation found in the Navajo and Apache population causes SCID and radiation intolerance.
The signs and symptoms of paracetamol toxicity occur in three phases. The first phase begins within hours of overdose, and consists of nausea, vomiting, a pale appearance, and sweating. However, patients often have no specific symptoms or only mild symptoms in the first 24 hours of poisoning. Rarely, after massive overdoses, patients may develop symptoms of metabolic acidosis and coma early in the course of poisoning. The second phase occurs between 24 hours and 72 hours following overdose and consists of signs of increasing liver damage. In general, damage occurs in liver cells as they metabolize the paracetamol. Hallmark pathology on liver biopsy includes regions of coagulative necrosis in zone 3 of the liver acinus, around the central venules, as these hepatocytes have higher concentrations of cytochrome P450 enzymes compared to zone 1 hepatocytes surrounding the portal venule of the acinus. Remaining viable hepatocytes frequently show ballooning injury and steatosis. The individual may experience right upper quadrant abdominal pain. The increasing liver damage also changes biochemical markers of liver function; International normalized ratio (INR) and the liver transaminases ALT and AST rise to abnormal levels. Acute kidney failure may also occur during this phase, typically caused by either hepatorenal syndrome or multiple organ dysfunction syndrome. In some cases, acute kidney failure may be the primary clinical manifestation of toxicity. In these cases, it has been suggested that the toxic metabolite is produced more in the kidneys than in the liver.
=== Immunosuppression and myelosuppression === Virtually all chemotherapeutic regimens can cause depression of the immune system, often by paralysing the bone marrow and leading to a decrease of white blood cells, red blood cells, and platelets. Anemia and thrombocytopenia may require blood transfusion. Neutropenia (a decrease of the neutrophil granulocyte count below 0.5 billion/litre) can be improved with synthetic G-CSF (granulocyte-colony-stimulating factor, e.g., filgrastim, lenograstim, efbemalenograstim alfa). In very severe myelosuppression, which occurs in some regimens, almost all the bone marrow stem cells (cells that produce white and red blood cells) are destroyed, meaning allogenic or autologous bone marrow cell transplants are necessary. (In autologous BMTs, cells are removed from the person before the treatment, multiplied and then re-injected afterward; in allogenic BMTs, the source is a donor.) However, some people still develop diseases because of this interference with bone marrow. Although people receiving chemotherapy are encouraged to wash their hands, avoid sick people, and take other infection-reducing steps, about 85% of infections are due to naturally occurring microorganisms in the person's own gastrointestinal tract (including oral cavity) and skin. Dental evaluation and treatment before cytotoxic chemotherapy is recommended for reducing the risk of oral and systemic infections during the neutropenic phase.
Sources: en.wikipedia.org
It is a chain of 28 amino acids, with an acetyl group attached to the first serine residue. The synthetic version replicates this sequence. Its molecular mass is about 3,108 daltons.
It is usually described as an immunomodulatory peptide rather than a classic hormone. It acts on immune cells through receptor pathways. No single endocrine organ target defines its function.
Several countries, including Italy and China, allow it for specific indications. The FDA has not approved it as a drug in the United States. Availability depends on local regulation.
Cool storage below freezing is usual for long-term retention, with a desiccant and protection from light. Portions are often split before first use to avoid repeated handling.