The short version of thymus extract fits in a sentence. The long version — which is the one that helps — is below.
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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。
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.
| 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 |
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.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
Thymosin alpha 1 is a short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
=== Modulation techniques === Modulation techniques make use of the fact that technical noise usually decreases with increasing frequency (which is why it is often referred to as 1/f noise) and improve the signal to noise ratio by encoding and detecting the absorption signal at a high frequency, where the noise level is low. The most common modulation techniques are wavelength modulation spectroscopy (WMS) and frequency modulation spectroscopy (FMS). In WMS the wavelength of the light is continuously scanned across the absorption profile, and the signal is detected at a harmonic of the modulation frequency. In FMS, the light is modulated at a much higher frequency but with a lower modulation index. As a result, a pair of sidebands separated from the carrier by the modulation frequency appears, giving rise to a so-called FM-triplet. The signal at the modulation frequency is a sum of the beat signals of the carrier with each of the two sidebands. Since these two sidebands are fully out of phase with each other, the two beat signals cancel in the absence of absorbers. However, an alteration of any of the sidebands, either by absorption or dispersion, or a phase shift of the carrier, will give rise to an unbalance between the two beat signals, and therefore a net-signal. Although in theory baseline-free, both modulation techniques are usually limited by residual amplitude modulation (RAM), either from the laser or from multiple reflections in the optical system (etalon effects).
=== Sensor === The Dexcom sensor operates as an implantable electrochemical device that continuously measures glucose levels in the interstitial fluid beneath the skin. It consists of a non-conductive body housing three electrodes: a working electrode that reacts with glucose, a reference electrode that maintains a constant voltage, and a counter electrode that completes the electrical circuit. The counter electrode is designed with a larger reactive surface area to enhance measurement accuracy. These components are inserted into the subcutaneous tissue using an applicator. A multi-layer membrane covers the electrodes, regulating the diffusion of substances to the sensor and promoting stable, reliable readings. The resulting electrical signal is transmitted by the Dexcom transmitter to a compatible receiver or smart device for real-time glucose monitoring. Until the release of the Dexcom G7 and Stelo, the sensor and transmitter were separate components, with the transmitter snapping into the sensor. However, the G7 and Stelo models integrate both the sensor and transmitter into a single, disposable system.
==== Transport through the nuclear membrane ==== The actin sequence does not contain a nuclear localization signal. The small size of actin (about 43 kDa) allows it to enter the nucleus by passive diffusion. The import of actin into the nucleus (probably in a complex with cofilin) is facilitated by the import protein importin 9. Low levels of actin in the nucleus seems to be important, because actin has two nuclear export signals (NES) in its sequence. Microinjected actin is quickly removed from the nucleus to the cytoplasm. Actin is exported at least in two ways, through exportin 1 and exportin 6. Specific modifications, such as SUMOylation, allows for nuclear actin retention. A mutation preventing SUMOylation causes rapid export of beta actin from the nucleus.
=== Decrypting proteins of unknown biological function === The biochemical function of protein targets identified through gene knockout or proteomics approaches are often obscure if they have low amino acid sequence homology with proteins of known function. In many cases some useful information can be gained through the identification of binding cofactors or substrate analogs in classifying protein function, information useful in using Thermofluor can assist in "decrypting" the function of proteins whose biochemical function might otherwise be unknown.
Sources: en.wikipedia.org
== Etymology == The term "polymer" derives from Greek πολύς (polus) 'many, much' and μέρος (meros) 'part'. The term was coined in 1833 by Jöns Jacob Berzelius, though with a definition distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, who spent the next decade finding experimental evidence for this hypothesis.
Belizean Creoles are primarily mixed-raced descendants of West and Central Africans who were brought to the British Honduras (modern Belize along the Bay of Honduras) as well as the English and Scottish log cutters, known as the Baymen. Over the years they have also intermarried with Miskito from Nicaragua, Jamaicans and other Caribbean people, Mestizos, Europeans, Garifunas, Maya, etc. The majority of Creoles trace their ancestry to several of the aforementioned groups. The creole and African slaves came to British Honduras (modern day Belize) from Jamaica, as Jamaica was the closest British colony administering British Honduras at the time and it was the slave ships' final destination. It is also mentioned that many slaves brought to Belize were trouble makers and resisters from Jamaican sugar cane plantations. Belize town was the epicentre of the colony and many slaves ended up in the logwood and timber industry. Women and children stayed doing domestic and farm work. Slaves in Belize were more free to travel and roam around the colony due to their work. This caused the rapid integration of African slaves from different tribes and parts of Africa to mingle with the free coloureds and sons and daughters of slave owners with slaves. Some predominant coloured or light-skinned creole communities were in the Belize river valley: Crooked Tree, Isabela Bank, Bermudian Landings and Lemonal, among others. Most of them have light or blue eyes and light skin.
=== Pharmacokinetics === Topilutamide is a topical medication and is applied to the scalp. Topilutamide degrades in human serum at 37 °C with a half-life of approximately 6 hours and is undetectable after 48 hours. Perfluoroacylamido-arylpropanamides decompose hydrolytically to BP-34 and their corresponding perfluorocarboxylic acid. In the case of topilutamide, that perfluorocarboxylic acid is trifluoroacetic acid. The two metabolites of topilutamide namely BP-34 and trifluoroacetic acid were undetectable in human serum (below the detection limit of 5 ng/mL) along with the parent compound topilutamide, in human studies. BP-34 was shown to be devoid of anti-androgenic activity.
Historic England. "Bawdsey Chain Home Station (1309533)". Research records (formerly PastScape). Retrieved 9 October 2015. Historic England. "Great Bromley Chain Home Station (1476819)". Research records (formerly PastScape). Retrieved 9 October 2015. Historic England. "Canewdon Chain Home Station (1412472)". Research records (formerly PastScape). Retrieved 9 October 2015. Historic England. "Dunkirk Chain Home Station (1377189)". Research records (formerly PastScape). Retrieved 9 October 2015. Historic England. "High Street Chain Home Station (1476863)". Research records (formerly PastScape). Retrieved 9 October 2015. Historic England. "Pevensey Chain Home Station (1476551)". Research records (formerly PastScape). Retrieved 9 October 2015. Historic England. "Rye Chain Home Station (1476520)". Research records (formerly PastScape). Retrieved 9 October 2015. Historic England. "Ventnor Chain Home Station (1306901)". Research records (formerly PastScape). Retrieved 9 October 2015. Early Radar Memories Archived 2 September 2010 at the Wayback Machine Memories of Sgt. Jean Semple, one of Britain's pioneer radar operators RAF Bawdsey Chain Home Radar Station at Subterranean Britain RAF Radar Museum RAF High Street picture Life at Darsham Deprecated link archived 19 April 2013 at archive.today – BBC Great Baddow Chain Home Mast & Radar Anniversary Chain Home Radar – A Personal Reminiscence, M Scanlan, GEC Review, 1993 Early radar development in the UK at purbeckradar.co.uk 60 (Signals) Group, Fighter Command Archived 16 November 2017 at the Wayback Machine (pdf)
The order offered sickness and death insurance, assuring its members would be buried by Jewish law and become good American citizens. Order of United Hebrew Brothers - Founded in 1915. in 1917 was reported to have 1,800 members and 12 lodges in New York City. Orders stated objectives included promoting social intercourse, discussions of subjects relating to their community, and acting upon them. Provided free burials, helped members in distress, and encouraged enrollment in the Postal Life Insurance Company. United Order of True Sisters - Founded by Henrietta Bruckman, wife of a prominent New York doctor, with 12 other ladies to assist Hebrew housewives. Had 5,991 members in 21 lodges in 1918. Had 12,000 members in 1995. Headquarters in New York. National structure called "Grand Lodge". Has degrees, secret ritual regalia, etc. Originally German-speaking, the first English lodge was organized in 1892, by 1918 German language was "essentially discontinued in all lodges". Although originally a benevolent society for sick and widows, by the late 1970s, had become primarily a philanthropic group, particularly with cancer-related causes. The United Order True Sister Inc, Cancer Service created in 1947, contributes $300,000 a year to cancer patients and specialized care hospitals in 13 and Israel. Workmen's Circle
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 a fragment of the larger protein prothymosin alpha, which is present in many tissues. The isolated 28-amino-acid peptide was originally obtained from thymus preparations, and the pharmaceutical product is synthesized rather than extracted. The term therefore describes both a natural fragment and a manufactured drug substance.