lyophilized powder is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-10-02. Numbers and descriptions here follow the published literature rather than marketing material.
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。
Thymosin alpha-1 is supplied as a lyophilized powder in most research settings. The solid dissolves readily in water and in common aqueous buffers, and it is typically reconstituted shortly before use. Solutions are clear and colourless at ordinary working concentrations. Because the peptide is hygroscopic, weighing and reconstitution are usually performed with minimal exposure to ambient air. Aliquots are prepared to avoid repeated freeze-thaw cycles, and working solutions are kept cold.
Long-term storage is generally at minus twenty degrees Celsius or colder, preferably desiccated and protected from light. Lyophilized material is more stable than reconstituted solution, which degrades faster at room temperature. Stability depends on pH, ionic strength, and the presence of oxidising agents. Published stability data for the peptide are limited, so storage claims in catalogues should be treated as general guidance rather than measured guarantees. Freeze-thaw cycles are kept to a minimum.
Identity and purity are normally confirmed by reversed-phase high-performance liquid chromatography and mass spectrometry. The expected mass for the acetylated 28-residue peptide is close to 3108 daltons, and a mass shift indicates a modification or truncation. Peptide mapping after enzymatic digestion can resolve sequence-level questions. Counter-ion content, water content, and residual solvents are separate quality attributes that a certificate of analysis may or may not report. Aggregation is monitored by size-exclusion chromatography when relevant.
| 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 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.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
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.
The lyophilized peptide is generally stable for extended periods when kept cold and dry. Once dissolved, aqueous solutions are less stable; hydrolysis, oxidation, and aggregation can degrade the material. Storage at -20 °C or lower slows these processes. Repeated freeze-thaw cycles are best avoided because they can promote aggregation. The exact shelf life depends on formulation, pH, and concentration, so stability studies are typically performed for each specific product.
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.
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.
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.
=== Controversy === In 2010, Novo Nordisk breached the Association of the British Pharmaceutical Industry's code of conduct by failing to provide information about side effects, and by promoting it prior to being granted market authorization. In 2012, the non-profit consumer advocacy group Public Citizen petitioned the US Food and Drug Administration (FDA) to immediately remove liraglutide from the market because they concluded that risks of thyroid cancer and pancreatitis outweigh any documented benefits. In 2017, Novo Nordisk agreed to pay $58.65 million to settle multiple whistleblower lawsuits alleging that the company had illegally marketed, promoted, and sold Victoza for off-label uses (such as for type 1 diabetes) in violation of the Federal Food, Drug, and Cosmetic Act and the False Claims Act. Novo Nordisk paid an additional $1.45 million to the states of California and Illinois to settle whistleblower cases alleging fraud against private commercial health insurers.
=== Infection === TPN requires a chronic IV access for the solution to run through, and the most common complication is infection of this catheter. Infection is a common cause of death in these patients, with a mortality rate of approximately 15% per infection, and death usually results from septic shock. When using central venous access, the subclavian (or axillary) vein is preferred due to its ease of access and lowest infectious complications compared to the jugular and femoral vein insertions. Catheter complications include pneumothorax, accidental arterial puncture, and catheter-related sepsis. The complication rate at the time of insertion should be less than 5%. Catheter-related infections may be minimised by appropriate choice of catheter and insertion technique.
The properties of a hydrogel are highly dependent on the type and quantity of its crosslinks, making photopolymerization a popular choice for fine-tuning hydrogels. This technique has seen considerable use in cell and tissue engineering applications due to the ability to inject or mold a precursor solution loaded with cells into a wound site, then solidify it in situ. Physically crosslinked hydrogels can be prepared by different methods depending on the nature of the crosslink involved. Polyvinyl alcohol hydrogels are usually produced by the freeze-thaw technique. In this, the solution is frozen for a few hours, then thawed at room temperature, and the cycle is repeated until a strong and stable hydrogel is formed. Alginate hydrogels are formed by ionic interactions between alginate and double-charged cations. A salt, usually calcium chloride, is dissolved into an aqueous sodium alginate solution, that causes the calcium ions to create ionic bonds between alginate chains. Gelatin hydrogels are formed by temperature change. A water solution of gelatin forms an hydrogel at temperatures below 37–35 °C, as Van der Waals interactions between collagen fibers become stronger than thermal molecular vibrations.
Sources: en.wikipedia.org
In May 2021, Wolfire Games filed a proposed class-action antitrust lawsuit against Valve, alleging that the company exerts monopoly power over the PC gaming market and uses its "gatekeeper role" to "wield extreme power over publishers of PC Desktop Games" and to extract "an extraordinarily high cut from nearly every sale that passes through its store." Although a motion by Valve to dismiss the original lawsuit was granted in November 2021, Wolfire was allowed to file a revised complaint, and in May 2022 US District Court Judge John C. Coughenour ruled that that lawsuit could proceed, finding that Wolfire's allegations were "sufficient to plausibly allege unlawful conduct." In November 2024, it was affirmed into a class-action lawsuit, with any developer affected by Valve's revenue cut able to be part of the class. In June 2024, Vicki Shotbolt, a children's digital rights activist, filed a lawsuit with the Competition Appeal Tribunal in the UK that accuses Valve of "rigging the market" for PC games, alleging that Valve used its market dominance to overcharge 14 million people in the UK and seeking damages of £22 to £44 per affected customer, or £656 million in total.
The gallbladder is a hollow part of the biliary tract that sits just beneath the liver, with the gallbladder body resting in a small depression. It is a small organ where the bile produced by the liver is stored, before being released into the small intestine. Bile flows from the liver through the bile ducts and into the gall bladder for storage. The bile is released in response to cholecystokinin (CCK), a peptide hormone released from the duodenum. The production of CCK (by endocrine cells of the duodenum) is stimulated by the presence of fat in the duodenum. It is divided into three sections, a fundus, body and neck. The neck tapers and connects to the biliary tract via the cystic duct, which then joins the common hepatic duct to form the common bile duct. At this junction is a mucosal fold called Hartmann's pouch, where gallstones commonly get stuck. The muscular layer of the body is of smooth muscle tissue that helps the gallbladder contract, so that it can discharge its bile into the bile duct. The gallbladder needs to store bile in a natural, semi-liquid form at all times. Hydrogen ions secreted from the inner lining of the gallbladder keep the bile acidic enough to prevent hardening. To dilute the bile, water and electrolytes from the digestion system are added. Also, salts attach themselves to cholesterol molecules in the bile to keep them from crystallising. If there is too much cholesterol or bilirubin in the bile, or if the gallbladder does not empty properly the systems can fail.
At 11:07, radar detected another, larger attack. This second wave consisted of 107 aircraft. They were met while still 60 miles (97 km) out, and at least 70 of these aircraft were shot down before reaching the ships. Six attacked Rear Admiral Alfred E. Montgomery's group, nearly hitting two of the carriers and causing casualties on each. Four of the six were shot down. A small group of torpedo aircraft attacked Enterprise, with one torpedo exploding in the wake of the ship. Three other torpedo aircraft attacked the light carrier Princeton and were shot down. In all, 97 of the 107 attacking aircraft were destroyed. A third raid, consisting of 47 aircraft, came in from the north. It was intercepted by 40 fighters at 13:00, while 50 miles (80 km) out from the task force. Seven Japanese aircraft were shot down. A few broke through and made an ineffective attack on Task Group 58.4. Many others did not press home their attacks. This raid therefore suffered less than the others, and 40 of its aircraft managed to return to their carriers. A fourth Japanese raid was launched between 11:00 and 11:30, but pilots had been given an incorrect position for the U.S. fleet and could not locate it. They broke into two loose groups and turned for Guam and Rota to refuel. One group flying toward Rota stumbled upon Montgomery's task group. Eighteen aircraft joined battle with American fighters and lost half their number. A smaller group of nine Japanese dive bombers of this force evaded U.S. aircraft and attacked Wasp and Bunker Hill but scored no hits; eight were shot down.
Sources: en.wikipedia.org
SRM has been used to identify the proteins encoded by wild-type and mutant genes (mutant proteins) and quantify their absolute copy numbers in tumors and biological fluids, thus answering the basic questions about the absolute copy number of proteins in a single cell, which will be essential in digital modelling of mammalian cells and human body, and the relative levels of genetically abnormal proteins in tumors, and proving useful for diagnostic applications. SRM has also been used as a method of triggering full product ion scans of peptides to either a) confirm the specificity of the SRM transition, or b) detect specific post-translational modifications which are below the limit of detection of standard MS analyses. In 2017, SRM has been developed to be a highly sensitive and reproducible mass spectrometry-based protein targeted detection platform (entitled "SAFE-SRM"), and it has been demonstrated that the SRM-based new pipeline has major advantages in clinical proteomics applications over traditional SRM pipelines, and it has demonstrated a dramatically improved diagnostic performance over that from antibody-based protein biomarker diagnostic methods, such as ELISA.
==== Metabolism ==== Not many studies have been conducted on the biotransformation of bromazolam, mainly because this drug is relatively new. However, in a study of Wagmann et al. (2020), the biotransformation of bromazolam is studied in depth. The results of this study are described in the text below. Blood plasma and urine of two individuals suspected of taking bromazolam were analysed for bromazolam and its metabolites. Bromazolam was detected in all four of the samples. One of the urine samples contained 8 bromazolam metabolites these were: phenyl-hydroxy bromazolam, 4-hydroxy bromazolam, α-hydroxy bromazolam, α-4-dihydroxy bromazolam, bromazolam N-glucuronide, phenyl-hydroxy bromazolam glucuronide, α-hydroxy bromazolam glucuronide, and 4-hydroxy bromazolam glucuronide. In the blood plasma sample of the same individual only the three mono-hydroxylated metabolites were found. The urine of the other individual only contained two metabolites, which were also found in the other urine sample, and the blood plasma did not show any metabolite of bromazolam present in the body. A study where pooled human liver S9 fractions (pHLS9) were incubated with bromazolam was conducted. Seven, out of the eight urine, bromazolam metabolites were found in the pHLS9 samples. Phenyl-hydroxylated glucuronide bromazolam was not found in the pHLS9 samples. Several monooxygenases and glucuronosyltransferases have been screened, in vitro, for activity of the biotransformation of bromazolam.
The Scottish Government had wanted it delayed until after a separate hearing into determining the definition of a woman. 6 August – Five people are arrested when protestors interrupt the Men's Elite Road Race at Falkirk. The environmental protest group This Is Rigged claims responsibility. 7 August – Police Scotland confirms that the bodies of three hillwalkers have been found after they failed to return from a trip to Aonach Eagach Ridge in Glen Coe two days earlier. Education staff at ten local authorities who belong to the Unite union vote to take rolling industrial action after rejecting a pay offer from the Scottish Government. 8 August – Jamie Starrs is sentenced to ten and a half years in prison for the rape of Amber Gibson in June 2021, five months before she was murdered by her brother. 9 August – The names of several thousand people adopted as children going back 100 years are removed from the ScotlandsPeople website amid concerns over privacy and safety. 10 August – Social Security Scotland issues an apology over a staff quiz that included pictures of child killers. The Friday Fun Quiz asked staff to identify people called Ian from images, and includes pictures of Ian Brady and Ian Huntley. 11 August – At the High Court in Stirling, James White, the leader of one of Scotland's largest organised crime gangs who was extradited from Brazil to face trial, is sentenced to ten years in prison for series organised crime and firearms offences. 12 August – Police Scotland announces plans to cut civilian staff and freeze recruitment in order to maintain officer numbers.
=== Food additive === Silica gel, also referred to as silicon dioxide or synthetic amorphous silica (SAS), is listed by the FDA in the United States as generally recognized as safe (GRAS), meaning it can be added to food products without needing approval. Silica is allowed to be added to food in the US at up to 2% as permitted under 21 CFR 172.480. In the EU, it can be in up to 5% concentrations. In 2018, a re-evaluation by the EFSA Panel on Food Additives and Nutrient Sources added to Food found no indications of toxicity even at the highest estimates of exposure level. Listed uses include: anticaking agent, defoaming agent, stabilizer, adsorbent, carrier, conditioning agent, chill proofing agent, filter aid, emulsifying agent, viscosity control agent, and anti-settling agent. Silica can be found commonly in foods including baked goods, spices and herbs, dairy products, cocoa products, and more.
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。
Lyophilized powder is normally kept at minus twenty degrees Celsius or below, in a sealed container, desiccated and away from light. Reconstituted solutions are less stable and are usually refrigerated and used quickly. Repeated temperature cycling should be avoided.