A practical reference on chronic hepatitis B: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-07-25 and is reviewed periodically as new material appears.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Molecular mass | Approximately 3,108 Da | Consistent with a 28-residue acetylated peptide |
| Residue count | 28 | Corresponds to the amino terminal region of prothymosin alpha |
| Appearance of dry powder | White to off-white solid | Slight variation between lots is normal |
| Solubility class | Freely soluble in water | Low solubility in most organic solvents |
| Common synonyms | Thymosin alpha 1, T alpha 1 | The numeral reflects an early fraction numbering scheme |
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.
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.
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.
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.
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.
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.
Only 249Bk is available in large quantities; it has a relatively short half-life of 330 days and emits mostly soft β-particles, which are inconvenient for detection. Its alpha radiation is rather weak (1.45×10−3% with respect to β-radiation), but is sometimes used to detect this isotope. 247Bk is an alpha-emitter with a long half-life of 1,380 years, but it is hard to obtain in appreciable quantities; it is not formed upon neutron irradiation of plutonium because β-decay of curium isotopes with mass number below 248 is not known. (247Cm would actually release energy by β-decaying to 247Bk, but this has never been seen.) The 20 isotopes of californium with mass numbers 237–256 are formed in nuclear reactors; californium-253 is a β-emitter and the rest are α-emitters. The isotopes with even mass numbers (250Cf, 252Cf and 254Cf) have a high rate of spontaneous fission, especially 254Cf of which 99.7% decays by spontaneous fission. Californium-249 has a relatively long half-life (352 years), weak spontaneous fission and strong γ-emission that facilitates its identification. 249Cf is not formed in large quantities in a nuclear reactor because of the slow β-decay of the parent isotope 249Bk and a large cross section of interaction with neutrons, but it can be accumulated in the isotopically pure form as the β-decay product of (pre-selected) 249Bk. Californium produced by reactor-irradiation of plutonium mostly consists of 250Cf and 252Cf, the latter being predominant for large neutron fluences, and its study is hindered by the strong neutron radiation.
=== Unapproved analogues overview === Many experimental insulin analogues are being developed to improve diabetes treatment. These include new injectable types and oral forms. Oral insulin is being studied as a way to avoid injections and better match natural insulin delivery.
The cable sent from NATO headquarters on 11 August 2008 said that "A number of Allies - especially Germany - are parroting Russian points on Georgian culpability for the crisis" and "intelligence releasable to NATO Allies on this point might be a useful tool" to counter these allegations. One cable reported on 14 August: "Merabishvili told us that the escalation of the conflict occurred after the villages of Nuli and Avnevi were destroyed. Since OSCE observers were hunkered down in Tskhinvali, they could not hear the bombing in Avnevi". The cable reported on 15 August that Ainārs Šlesers, Latvian minister of transport, who suggested that Saakashvili was guilty for the war, made money on deals involving Russia. Russian ambassador to Latvia appealed to business interests of Latvian politicians to prevent sanctioning of Russia.
== High-level details == Good manufacturing practice guidelines provide guidance for manufacturing, testing, and quality assurance in order to ensure that a manufactured product is safe for human consumption or use. Many countries have legislated that manufacturers follow GMP procedures and create their own GMP guidelines that correspond with their legislation. All guidelines follow a few basic principles:
Sources: en.wikipedia.org
The trade and Hong Kong concessions were a result of the 1841 Convention of Chuenpi (signed by Qishan and Charles Elliot and the 1842 Treaty of Nanking (signed by Henry Pottinger, Keying, and Yilibu). The opium trade incurred intense enmity from the later British Prime Minister William Ewart Gladstone. As a member of Parliament, Gladstone called it "most infamous and atrocious" referring to the opium trade between China and British India in particular. Gladstone was fiercely against both of the Opium Wars Britain waged in China in the First Opium War initiated in 1840 and the Second Opium War initiated in 1857, denounced British violence against Chinese, and was ardently opposed to the British trade in opium to China. Gladstone lambasted it as "Palmerston's Opium War" and said that he felt "in dread of the judgments of God upon England for our national iniquity towards China" in May 1840. A famous speech was made by Gladstone in Parliament against the First Opium War. Gladstone criticized it as "a war more unjust in its origin, a war more calculated in its progress to cover this country with permanent disgrace". His hostility to opium stemmed from the effects of opium brought upon his sister Helen. Due to the First Opium war brought on by Palmerston, there was initial reluctance to join the government of Peel on part of Gladstone before 1841.
=== Nanoparticles === The most promising drug delivery system is using nanoparticle delivery systems, these are systems where the drug is bound to a nanoparticle capable of traversing the blood–brain barrier. The most promising compound for the nanoparticles is Human Serum Albumin (HSA). The main benefits of this is that particles made of HSA are well tolerated without serious side effects as well as the albumin functional groups can be utilized for surface modification that allows for specific cell uptake. These nanoparticles have been shown to transverse the blood–brain barrier carrying host drugs. To enhance the effectiveness of nanoparticles, scientists are attempting to coat the nanoparticles to make them more effective to cross the blood–brain barrier. Studies have shown that "the overcoating of the [nanoparticles] with polysorbate 80 yielded doxorubicin concentrations in the brain of up to 6 μg/g after i.v. injection of 5 mg/kg" as compared to no detectable increase in an injection of the drug alone or the uncoated nanoparticle. This is very new science and technology so the real effectiveness of this process has not been fully understood. However young the research is, the results are promising pointing to nanotechnology as the way forward in treating a variety of brain diseases.
Singapore has a tropical rainforest climate (Köppen: Af) with no distinctive seasons, uniform temperature and pressure, high humidity, and abundant rainfall. Temperatures usually range from 23 to 32 °C (73 to 90 °F). While temperature does not vary greatly throughout the year, there is a wetter monsoon season from November to February. From July to October, there is often haze caused by bush fires in neighbouring Indonesia, usually from the island of Sumatra. Singapore follows the GMT+8 time zone, one hour ahead of the typical zone for its geographical location. This causes the sun to rise and set particularly late during February, where the sun rises at 7:15 am and sets around 7:20 pm. During July, the sun sets at around 7:15 pm. The earliest the sun rises and sets is in late October and early November when the sun rises at 6:46 am and sets at 6:50 pm. Singapore recognises that climate change and rising sea levels in the decades ahead will have major implications for its low-lying coastline. It estimates that the nation will need to spend $100 billion over the course of the next century to address the issue. In its 2020 budget, the government set aside an initial $5 billion towards a Coastline and Flood Protection Fund. Singapore is the first country in Southeast Asia to levy a carbon tax on its largest carbon-emitting corporations producing more than 25,000 tons of carbon dioxide per year, at $5 per ton.
In the United States alone, sales of the Invega franchise (including Sustenna, Trinza, and Hafyera) reached $3.1 billion in 2024, an 8% increase over the previous year. The market is served primarily by Janssen Pharmaceuticals, with generic competition expected to begin after the key U.S. patent expires on January 26, 2031.
=== Quigley Company asbestos settlement (2013) === The Quigley Company, which sold asbestos-containing insulation products until the early 1970s, was acquired by Pfizer in 1968. In June 2013, asbestos victims and Pfizer negotiated a settlement that required Pfizer to pay a total of $964 million: $430 million to 80% of existing plaintiffs and place an additional $535 million into a settlement trust that will compensate future plaintiffs as well as the remaining 20% of plaintiffs with claims against Pfizer and Quigley. Of that $535 million, $405 million is in a 40-year note from Pfizer, while $100 million is from insurance policies.
Sources: en.wikipedia.org
The name reflects an early convention for naming thymus-derived fractions. The peptide is characterized and measured as a defined molecule, and it does not operate through a single classical endocrine axis.
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。