If you have been reading about thymic extract 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 2025-11-24. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
Reverse-phase high-performance liquid chromatography is the standard technique for assessing purity and concentration, because the peptide's hydrophobicity allows clean separation from related impurities. Mass spectrometry confirms molecular identity and detects sequence errors or truncations. Amino acid analysis and peptide mapping supply additional structural confirmation when required. Chromatographic purity values reported on certificates of analysis describe the proportion of the main peak and do not by themselves establish biological activity.
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.
| 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 |
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.
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
Thymosin alpha 1 is a 28-amino-acid peptide first isolated from thymosin fraction 5, a bovine thymic extract. Its sequence begins with an acetylated serine residue and carries a high proportion of acidic residues, so the molecule has a net negative charge near neutral pH. Despite the shared name, it is unrelated in sequence to the thymosin beta family. Synthetic material prepared by solid-phase peptide synthesis is identical in sequence to the natural peptide.
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
The Revolt, written by Menachem Begin before he became Prime Minister, tells the story of the Lehi (referred to by their translated name's acronym, F.F.I. "Freedom Fighters of Israel" in early English editions) and Begin's own Irgun fighters during the Jewish insurgency in Palestine. The Revolt influenced groups from a wide variety of ideologies. Some of these groups began to use suicide attacks in the 1990s. The book was allegedly found Osama bin Laden's al-Qaeda organization. Begin praised his militants' willingness to die, "These two wonderful young men greeted the sentence with the singing of Hatikvah". The "two wonderful young men" were the two who blew themselves up in 1947, he described their deaths, "even before they put on their red uniforms. They too held their heads high when they faced their judges… But they did not reach the gallows. They too sang on the threshold of death — a song of faith in God: 'Lord of the world who reigned before creation'. But their song ended with a great explosion which shattered the silence of the prison in occupied Jerusalem". In 1977 the author became prime minister, after previously being in opposition. Historical militants featured prominently in his political speeches. He praised the actions of his militants during the insurgency in Palestine in the 1940s, including the leader of the cell who bombed the King David Hotel (killing 91 people and 1 terrorist). His favourites were, again, the two young militants who blew themselves up in Jerusalem prison in 1947.
=== 2025–present: Later work === Freeman returned to the heist franchise acting in Now You See Me: Now You Don't which was released in November 2025. It marks his first theatrical release in several years. Speaking about the possibility of retiring, Freeman said: "Sometimes the idea of retirement would float past me but, as soon as my agent says there's a job or somebody wants you or they've made an offer, the whole thing just boils back into where it was yesterday. 'how much you're going to pay, where we’re gonna be?' The appetite is still there. I will concede that it's dimmed a little. But not enough to make a serious difference."
== Procedure == When performing RK, incisions are made with a diamond knife. The incisions relax the steep central cornea in patients with myopia in order to achieve a decreased need for correction. The original technique – consisting of incisions from periphery to center – was called the "Russian technique", while the later advances of performing controlled incision from center to periphery was called the "American technique". RK may be performed with different types, numbers, and patterns of incisions. Typically, between 4 and 24 radial incisions are made in a number of patterns and orientations based on refractive errors, surgeon style and surgeon training. RK with 8 incisions is most common. Incisions that penetrate only the superficial corneal stroma are less effective than those reaching deep into the cornea, and consequently, incisions are made quite deep. One study cites incisions made to a depth equivalent to the thinnest of four corneal-thickness measurements made near the center of the cornea. Other sources cite surgeries leaving 20 to 50 micrometres of corneal tissue unincised (roughly equivalent to 90% of corneal depth, based on thickness norms).
Because water-soluble B vitamins are eliminated in the urine, taking large doses of most B vitamins usually only produces transient side effects (with the only exception being pyridoxine). General side effects may include restlessness, nausea, and insomnia. These side effects are almost always caused by dietary supplements and not food.
Higher education in Somalia is largely private. Several universities in the country have ranked among the 100 best African universities. Qu'ranic schools are the basic method of traditional religious instruction. They are the most stable method of non-formal education. It teaches the most students compared to other methods. It holds community support and uses local and widely abundant materials. It is often the only system accessible to Somalis in nomadic areas. The Somali government regulates it with the Ministry of Endowment and Islamic Affairs.
Sources: en.wikipedia.org
Those who eat it have visions of fearful things. Magicians or those who wish to harm someone administer it in food or drink. This herb is medicinal and its seed is used as a remedy for gout, ground up and applied to the part affected." Christian Rätsch has said, "A mild dosage produces medicinal and healing effects, a moderate dosage produces aphrodisiac effects, and high dosages are used for shamanic purposes". Wade Davis, an ethnobotanist, also lists it as an essential ingredient of a zombie potion in Haitian Vodou. In Western culture, the same species (Datura stramonium) has been said to have been commonly used by witches as an ingredient for their flying ointments and was regularly included in detailed recipes of magical ointments dating back as far as the early modern period, predominately in New England and Western Europe. During the anti-witchcraft hysteria of colonial times it was considered unlucky or inappropriate to grow D. stramonium in one's garden due to its supposed reputation for aiding in incantations.
=== PG === The hydrostatic pressure within the glomerular capillaries is determined by the pressure difference between the fluid entering immediately from the afferent arteriole and leaving through the efferent arteriole. The pressure difference is approximated by the product of the total resistance of the respective arteriole and the flux of blood through it:
==== 1965 - 1992 ==== Following the assassination of Kennedy in 1963, India-US relations deteriorated gradually. While Kennedy's successor Lyndon B. Johnson sought to maintain relations with India to counter Communist China, he also sought to strengthen ties with Pakistan with the hopes of easing tensions with China and weakening India's growing military buildup as well. Relations then hit an all-time low under the Nixon administration in the early 1970s. Nixon shifted away from the neutral stance which his predecessors had taken towards India-Pakistan hostilities. He established a very close relationship with Pakistan, aiding it militarily and economically, as India, now under the leadership of Indira Gandhi, was leaning towards Soviet Union. He considered Pakistan as a very important ally to counter Soviet influence in the Indian subcontinent and establish ties with China, with whom Pakistan was very close. The frosty personal relationship between Nixon and Indira further contributed to the poor relationship between the two nations. Nixon also harbored sexist and racist sentiments against Indians, describing the empathetic attitude of the American public toward India as a "psychological disorder". During the 1971 Indo-Pakistani War, the US openly supported Pakistan and deployed its aircraft carrier USS Enterprise towards the Bay of Bengal, which was seen as a show of force by the US in support of the West Pakistani forces.
Red blood cells of non-mammalian vertebrates are flattened and ovoid in form, and retain their cell nuclei. There is considerable variation in the types and proportions of white blood cells; for example, acidophils are generally more common than in humans. Platelets are unique to mammals; in other vertebrates, small nucleated, spindle cells called thrombocytes are responsible for blood clotting instead.
Sources: en.wikipedia.org
Both Neanderthals and modern humans took care of the elderly members of their societies during the Middle and Upper Paleolithic. Some sources claim that most Middle and Upper Paleolithic societies were possibly fundamentally egalitarian and may have rarely or never engaged in organized violence between groups (i.e. war). Some Upper Paleolithic societies in resource-rich environments (such as societies in Sungir, in what is now Russia) may have had more complex and hierarchical organization (such as tribes with a pronounced hierarchy and a somewhat formal division of labor) and may have engaged in endemic warfare. Some argue that there was no formal leadership during the Middle and Upper Paleolithic. Like contemporary egalitarian hunter-gatherers such as the Mbuti pygmies, societies may have made decisions by communal consensus decision making rather than by appointing permanent rulers such as chiefs and monarchs. Nor was there a formal division of labor during the Paleolithic. Each member of the group was skilled at all tasks essential to survival, regardless of individual abilities. Theories to explain the apparent egalitarianism have arisen, notably the Marxist concept of primitive communism. Christopher Boehm (1999) has hypothesized that egalitarianism may have evolved in Paleolithic societies because of a need to distribute resources such as food and meat equally to avoid famine and ensure a stable food supply. Raymond C.
== Further reading == Bryant, Alfred T. (1964). A History of the Zulu and Neighbouring Tribes. Cape Town: C. Struik. p. 157. Cana, Frank Richardson (1911). "Zululand" . Encyclopædia Britannica. Vol. 28 (11th ed.). pp. 1050–1055.
Between each step, the plate is typically washed with a mild detergent solution to remove any proteins or antibodies that are non-specifically bound. After the final wash step, the plate is developed by adding an enzymatic substrate to produce a visible signal, which indicates the quantity of antigen in the sample. Of note, ELISA can perform other forms of ligand binding assays instead of strictly "immuno" assays, though the name carried the original "immuno" because of the common use and history of the development of this method. The technique essentially requires any ligating reagent that can be immobilized on the solid phase along with a detection reagent that will bind specifically and use an enzyme to generate a signal that can be properly quantified. In between the washes, only the ligand and its specific binding counterparts remain specifically bound or "immunosorbed" by antigen-antibody interactions to the solid phase, while the nonspecific or unbound components are washed away. Unlike other spectrophotometric wet lab assay formats where the same reaction well (e.g., a cuvette) can be reused after washing, the ELISA plates have the reaction products immunosorbed on the solid phase, which is part of the plate and so are not easily reusable.
2024 United States elections 2024 United States gubernatorial elections 2024 United States House of Representatives elections 2024 United States Senate elections Timeline of the 2024 United States presidential election Republican Party efforts to disrupt the 2024 United States presidential election Fundraising in the 2024 United States presidential election
The use of adsorbent chemicals, such as zeolites, and other hemostatic agents are also used for sealing severe injuries quickly (such as in traumatic bleeding secondary to gunshot wounds). Thrombin and fibrin glue are used surgically to treat bleeding and to thrombose aneurysms. Hemostatic Powder Spray TC-325 is used to treated gastrointestinal bleeding. Desmopressin is used to improve platelet function by activating arginine vasopressin receptor 1A. Coagulation factor concentrates are used to treat hemophilia, to reverse the effects of anticoagulants, and to treat bleeding in people with impaired coagulation factor synthesis or increased consumption. Prothrombin complex concentrate, cryoprecipitate and fresh frozen plasma are commonly used coagulation factor products. Recombinant activated human factor VII is sometimes used in the treatment of major bleeding. Tranexamic acid and aminocaproic acid inhibit fibrinolysis and lead to a de facto reduced bleeding rate. Before its withdrawal, aprotinin was used in some forms of major surgery to decrease bleeding risk and the need for blood products.
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。
The lyophilized solid is normally held at 2 to 8 °C in a sealed, light-protected container. Dry storage limits both hydrolysis and microbial growth. Material kept this way remains stable for the shelf life stated by the supplier.