A practical reference on 细胞因子: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-06-23. Anything still debated is marked as such rather than presented as settled.
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.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Soluble in water | Also soluble in aqueous buffers |
| Storage temperature | -20 °C or below | Desiccated, protected from light |
| Typical analytical method | RP-HPLC with mass spectrometry | Purity and identity |
| Common synonyms | Thymalfasin, T alpha 1 | Sequence identical to natural fragment |
在信号层面，Tα1可能通过Toll样受体等模式识别受体发挥作用。部分实验显示，它能激活髓样分化因子88依赖的通路，进而促进核因子κB进入细胞核。这导致白细胞介素2、干扰素γ和白细胞介素12等细胞因子的转录增加。这些细胞因子偏向辅助性T细胞1型应答，有助于细胞免疫。然而，具体受体和结合位点尚未完全确定，不同实验模型的结果存在差异。
临床研究将Tα1用于慢性病毒感染、肿瘤辅助治疗和疫苗佐剂等场景。部分试验报告了免疫学指标改善，但临床终点获益在不同研究中并不一致。系统综述指出，研究间在人群、剂量和联合方案上差异较大，难以汇总结论。因此，Tα1的确切临床地位仍属开放问题，需要更多高质量随机对照试验来澄清。其机制研究也需从体外实验向体内模型推进。
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.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
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.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
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.
The most common response was the possibility of a Metabolic Myopathy that translates to a metabolic muscle illness and are usually caused by the muscle's inability to breakdown nutrients. The muscles begin to break themselves down to yield energy. As Angel gets closer to possibly having a diagnosis, she starts to think about a possible future with children. She worries that if her disease is genetic, she wouldn't want to put her children at risk. A medical student from Italy reaches out to Dr. Sanders. She describes her 4th- year thesis on metabolic gene testing that could be beneficial in narrowing down a diagnosis. Angel travels to Turin, Italy for blood and urine testing. The testing showed that Angel had a normal metabolic gene profile, which eliminated many possible metabolic disorders. The physicians in Italy submitted her genomes into a sequencing trial that could take up to two months to process but could hopefully result with a diagnosis. After the two months, Angel receives a call from the Physician with a complete result and a solid diagnosis of Carnitine Palmitoyltransferase II Deficiency.
A Pakistani newspaper, citing military sources, reported that seven TTP hideouts in Nangarhar, Paktika, and Khost provinces were destroyed and that more than 80 militants were killed; however, Taliban officials only reported airstrikes in the Nangarhar and Paktika provinces, adding that an airstrike in Bihsud District killed 18 civilians, including 11 children. Taliban officials condemned the airstrikes and warned of a calculated response at an appropriate time. Shayesteh Jan Ahadi, former head of the Paktia Provincial Council, stated that Pakistani airstrikes in several districts were very widespread and powerful. The United Nations Assistance Mission in Afghanistan (UNAMA) reported that Pakistan carried out airstrikes between 11:45 p.m. on 21 February and 12:15 a.m. on 22 February. UNAMA also reported that airstrikes in Paktika province damaged or destroyed infrastructure. On 23 February, UNAMA confirmed that over 13 civilians had been killed by the Pakistani airstrikes, with an additional seven injured. Pakistan described the operation as a retributive response to a series of suicide bombings inside Pakistan, including the 6 February bombing of a Shia mosque in Islamabad that killed 31 worshippers (claimed by ISIS–K), and attacks in Bajaur and Bannu districts in Khyber Pakhtunkhwa during the early days of Ramadan. Pakistan also claimed that the strikes were "intelligence-based, selective operations" against seven camps and hideouts belonging to the Tehreek-e-Taliban Pakistan (TTP), its affiliates, and the Islamic State – Khorasan Province (ISKP).
=== Class II === The heme group in class II cytochrome c proteins is attached to a C-terminal binding motif. The structural fold of class II c-type cytochromes contains a four α-helix bundle with the covalently attached heme group at its core. Representatives of class II are the high-spin cytochrome c' and a number of low-spin cytochromes c, e.g. cyt c556. The cyt c' are capable of binding such ligands as CO, NO or CN−, albeit with rate and equilibrium constants 100 to 1,000,000-fold smaller than other high-spin hemeproteins. This, coupled with its relatively low redox potential, makes it unlikely that cyt c' is a terminal oxidase. Thus cyt c' probably functions as an electron transfer protein. The 3D structures of a number of cyt c' have been determined which show that the proteins usually exist as a dimer. The Chromatium vinosum cyt c' exhibits dimer dissociation upon ligand binding.
Sources: en.wikipedia.org
=== 23 December === The Netherlands pledged up to 2.5 billion euros to help Ukraine in 2023. This aid was to pay for military equipment and rebuilding critical infrastructure. President Zelenskyy thanked them for this pledge.
Introduced in 1974, this analyzer used light scattering, absorbance and cell staining to identify the five normal white blood cell types in addition to "large unidentified cells", a classification that usually consisted of atypical lymphocytes or blast cells. The Hemalog D could count 10,000 cells in one run, a marked improvement over the manual differential. In 1981, Technicon combined the Hemalog D with the Hemalog-8 analyzer to produce the Technicon H6000, the first combined complete blood count and differential analyzer. This analyzer was unpopular with hematology laboratories because it was labour-intensive to operate, but in the late 1980s to early 1990s similar systems were widely produced by other manufacturers such as Sysmex, Abbott, Roche and Beckman Coulter.
Concerns expressed by some politicians on the subject of salvia reflect those of the media, with comparisons to LSD and particular focus on "protecting our children" being echoed; and with legislative proposals following soon after news stories breaking. Some arguments against salvia have been of a preventative nature, "We need to stop this before it gets to be a huge problem not after it gets to be a huge problem," or of an imitative nature, "The Australians have clearly found a problem with it. There's obviously a risk in people taking it." Concerns about driving while under the influence of salvia have also been expressed. Opponents of more prohibitive measures against salvia argue that such reactions are largely due to an inherent prejudice and a particular cultural bias rather than any actual balance of evidence, pointing out inconsistencies in attitudes toward other more toxic and addictive drugs such as alcohol and nicotine. While not objecting to some form of legal control, in particular with regard to the sale to minors or sale of enhanced high-strength extracts, most salvia proponents otherwise argue against stricter legislation. Those advocating consideration of Salvia divinorum's potential for beneficial use in a modern context argue that more could be learned from Mazatec culture, where salvia is not really associated with notions of drug taking at all and it is rather considered as a spiritual sacrament. In light of this it is argued that Salvia divinorum could be better understood more positively as an entheogen rather than pejoratively as a hallucinogen.
Cell-Based Bone Tissue Engineering Clinical Tissue Engineering Center. State of Ohio Initiative for Tissue Engineering (National Center for Regenerative Medicine). Organ Printing. Archived 28 August 2008 at the Wayback Machine. Multi-site NSF-funded initiative. LOEX Center. Université Laval Initiative for Tissue Engineering.
Sources: en.wikipedia.org
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.
Mass spectrometry gives the molecular mass, which is compared with the calculated value. Reversed-phase liquid chromatography shows purity and the presence of related impurities. Peptide mapping can verify the amino acid sequence when a higher level of detail is needed.
It reports the tests the supplier performed, which may vary between laboratories and lots. Methods and acceptance criteria are not standardised across suppliers. Buyers often request the actual chromatograms and spectra rather than a summary statement.
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。