The short version of 细胞因子 fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-11-07. Anything still debated is marked as such rather than presented as settled.
The lyophilized peptide is a white to off-white powder that dissolves freely in water and in aqueous buffers near neutral pH. Because the molecule carries a net negative charge under physiological conditions, saline and phosphate solutions are the usual vehicles, while strongly acidic media are avoided. Stock solutions are commonly divided into small aliquots so that repeated freezing and thawing can be limited, since cycling may encourage aggregation. Solubility in organic solvents is poor and those solvents are seldom used as primary diluents.
Recommended storage for the dry powder is a freezer near minus twenty degrees Celsius, kept desiccated and away from light. Once dissolved, the peptide is less stable and is usually held at two to eight degrees Celsius for short intervals or frozen for longer storage. Stability studies focus on the acetylated terminus and the disulfide linkage because those features define the intact molecule. Common degradation routes include cysteine oxidation, deamidation of asparagine or glutamine side chains, and slow formation of higher-molecular-weight species.
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.
Several names appear in the literature for this peptide, including thymalfasin and the abbreviation T-alpha-1. Naming conventions differ among research articles, regulatory documents, and supplier catalogs, which complicates literature searches. Both synthetic and recombinant production routes yield a peptide with the same 28-residue sequence as the thymic isolate. Because the thymosin label also covers unrelated peptides, sources should be compared by sequence rather than by name alone.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Assessed by visual inspection at release |
| Solubility class | Freely soluble in water | Aqueous buffers near neutral pH |
| Typical storage temperature | Minus 20 degrees Celsius | Lyophilized, desiccated, protected from light |
| Typical analytical method | Reverse-phase HPLC with mass spectrometry | Used together for purity and identity |
| Common synonyms | T-alpha-1; thymalfasin | Older reports use several designations |
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。
Lyophilized thymosin alpha 1 is typically stored refrigerated at 2 to 8 degrees Celsius and kept away from light. Reconstituted solutions are less stable and are usually used promptly after preparation. Repeated freeze-thaw cycles are avoided because they can promote aggregation and loss of activity. The peptide adsorbs to some plastic and glass surfaces, so a carrier protein is often added to dilute working solutions. Manufacturer instructions and published protocols both govern handling.
Identity and purity testing for thymosin alpha 1 relies mainly on reversed-phase high-performance liquid chromatography and mass spectrometry. Chromatography separates the parent peptide from truncated or modified variants, while mass spectrometry confirms the expected molecular mass. Amino acid analysis and peptide mapping provide additional sequence confirmation. Counterion content, water content, and residual solvents are measured separately as part of specification testing. No single method captures every attribute, so laboratories combine several techniques.
The peptide lacks cysteine, methionine, and tryptophan, so disulfide scrambling and sulfur oxidation are not major degradation routes. Instead, aspartate residues can undergo isomerization or cyclization to succinimide intermediates, generating isoaspartate variants. Hydrolysis of peptide bonds also occurs slowly in solution. These changes may reduce biological activity even when the main peak remains detectable. Stability studies therefore track both potency and the appearance of related substances.
It aids in normal mammary gland development. It is necessary for maintenance of the mammary bud cells. Loss of PTHrP or its receptor causes the mammary bud cells to change back into epidermal cells. In lactation, it may regulate the mobilization and transfer of calcium to the milk in conjunction with the calcium sensing receptors, as well as placental transfer of calcium.
The enzyme characterised from Saccharopolyspora erythraea converts erythromycin D into erythromycin C by introduction of a hydroxy group at the C-12 position of the macrocycle. It uses reduced nicotinamide adenine dinucleotide phosphate (NADPH) and oxygen as cofactors. Erythromycin C is subsequently converted to the antibiotic, erythromycin A, by the enzyme erythromycin 3''-O-methyltransferase.
The two-fold purpose of the double-lumen technology was: (i) the aesthetic benefits of silicone gel (contained in the inner lumen) that is enclosed within the outer lumen, which is filled with saline solution; and (ii) a breast prosthesis whose volume is post-operatively adjustable. In surgical practise, the double-lumen prosthetic breast is used primarily in reconstructive surgery of the breasts.
Sources: en.wikipedia.org
=== Irrigation === Proper cleansing of a wound is critical in preventing infection and promoting healing of any wound. Irrigation is defined as constant flow of a solution over the surface of a wound. The goal of irrigation is not only to remove debris and potential contaminants from a wound, but also to assist in visual inspection of a wound and hydrate the wound. Irrigation is typically achieved with either a bulb or syringe and needle/catheter. The preferred solution for irrigation is normal saline which is readily accessible in the emergency department, although recent studies have shown no difference in emergency department infection rates when comparing normal saline to potable tap water. Irrigation can also be achieved with a diluted 1% povidone iodine solution, but studies have again shown no difference in infection rates when compared to normal saline. Irrigation with antiseptic solutions, such as non-diluted povidone iodine, chlorhexidine, and hydrogen peroxide is not preferred since these solutions are toxic to tissue and inhibit wound healing. The exact volume of irrigation used will vary depending on the appearance of the wound, although some sources have reported 50–100 mL of irrigation per 1 cm of wound length as a guideline.
Other countries to do so are Canada, Georgia, Germany, Luxembourg, Malta, South Africa, and Thailand. In the U.S., the recreational use of cannabis is legalized in 24 states, 3 territories, and the District of Columbia, though the drug remains federally illegal. In Australia, it is legalized only in the Australian Capital Territory.
== Causes == The American Cancer Society noted that several factors contributed to escalating nationwide drug shortages, which included decreased or restricted drug manufacturing capacity, increased drug demands coupled with corresponding shortages in supplies, and lower profit margins for several generic drugs decreasing corporate desires towards creating surpluses. The organization also noted that the Food and Drug Administration's means to prevent drug shortages were fundamentally centered around contact with the drug manufacturers involved, giving early warnings that requested them to increase production instead of directly pushing for specific drug quotas. The ASHP reported that one of the main causes of continuous severe shortages was due to "extreme price competition" between generic drug manufacturers. Challenges to quick-enough production of high-quality medications coupled with possible supply chain disruptions pushed many of these companies to shift their manufacturing to producing drugs with higher profit margins, with some completely stopping production of less lucrative drugs. The organization also pointed out the role that difficult and multi-year federal regulatory approval processes for new manufacturers played in lowering the number of new drug manufacturers and resulting supply decreases. Generic drug user fees noted in section 506C(g) of the Federal Food Drug and Cosmetics Act further made it difficult for companies to keep their businesses profitable. U.S.
== Prognosis == Prognosis depends on the condition itself. Some conditions such as MS depend on the subtype of the disease and various attributes of the patient such as age, sex, initial symptoms, and the degree of disability the patient experiences. Life expectancy in MS patients is 5 to 10 years lower than unaffected people. MS is an inflammatory demyelinating disease of the central nervous system (CNS) that develops in genetically susceptible individuals after exposure to unknown environmental trigger(s). The bases for MS are unknown but are strongly suspected to involve immune reactions against autoantigens, particularly myelin proteins. The most accepted hypothesis is that dialogue between T-cell receptors and myelin antigens leads to an immune attack on the myelin-oligodendrocyte complex. These interactions between active T cells and myelin antigens provoke a massive destructive inflammatory response and promote continuing proliferation of T and B cells and macrophage activation, which sustains secretion of inflammatory mediators. Other conditions such as central pontine myelinolysis have about a third of patients recover and the other two-thirds experience varying degrees of disability. In some cases, such as transverse myelitis, the patient can begin recovery as early as 2 to 12 weeks after the onset of the condition.
Sources: en.wikipedia.org
== History == Kwashiorkor was present in the world long before 1933 when Cicely Williams published research that took the Ga name for the disease. There were already many names for the illness which referenced the cessation of breastfeeding, or the consumption of monotonous diets high in starch. However, Williams was the first to suggest that this might be a deficiency of protein or an amino acid. Despite publishing in 1933, it was only in 1949 that the World Health Organization officially recognized kwashiorkor as a public health concern. This period also correlated with the promotion of infant formula, often by European colonial powers. The substitution of formula for breastmilk contributed significantly to the increasing visibility of kwashiorkor throughout the twentieth century. Cicely Williams later described the promotion of formula as "the most criminal form of sedition, and that those deaths should be regarded as murder." These arguments underpinned the 1970s Nestlé boycott.
Benzodiazepines can be useful for short-term treatment of insomnia. Their use beyond 2 to 4 weeks is not recommended due to the risk of dependence. It is preferred that benzodiazepines be taken intermittently and at the lowest effective dose. They improve sleep-related problems by shortening the time spent in bed before falling asleep, prolonging sleep time, and reducing wakefulness. Like alcohol, benzodiazepines are commonly used to treat insomnia in the short-term (both prescribed and self-medicated), but worsen sleep in the long-term. While benzodiazepines can put people to sleep (i.e., inhibit NREM stage 1 and 2 sleep), while asleep, the drugs disrupt sleep architecture by decreasing sleep time, delaying time to REM sleep, and decreasing deep slow-wave sleep (the most restorative part of sleep for both energy and mood). Other drawbacks of hypnotics, including benzodiazepines, are possible tolerance to their effects, rebound insomnia, and reduced slow-wave sleep and a withdrawal period typified by rebound insomnia and a prolonged period of anxiety and agitation. The list of benzodiazepines approved for the treatment of insomnia is similar among most countries, but which benzodiazepines are officially designated as first-line hypnotics prescribed for the treatment of insomnia can vary distinctly between countries. Longer-acting benzodiazepines, such as nitrazepam and diazepam, have residual effects that may persist into the next day and are, in general, not recommended.
Research has shown that a mutation of G—>C in the −6 position of the β-globin gene (β+45; human) disrupted the haematological and biosynthetic phenotype function. This was the first mutation found in the Kozak sequence and showed a 30% decrease in translational efficiency. It was found in a family from the Southeast Italy and they suffered from thalassaemia intermedia. Similar observations were made regarding mutations in the position −5 from the start codon, AUG. Cytosine in this position, as opposed to thymine, showed more efficient translation and increased expression of the platelet adhesion receptor, glycoprotein Ibα in humans. Mutations to the Kozak sequence can also have drastic effects upon human health; in particular, certain forms of congenital heart disease are caused by Kozak sequence mutations in the GATA4 gene's 5' untranslated region. The GATA4 gene is responsible for gene expression in a wide variety of tissues including the heart. When the guanosine at the -6 position in the Kozak sequence of GATA4 is mutated to a cytosine, a reduction in GATA4 protein levels results, which leads to a decrease in the expression of genes regulated by the GATA4 transcription factor and linked to the development of atrial septal defect. The ability of the Kozak sequence to optimize translation can result in novel initiation codons in the typically untranslated region of the 5′ (5′ UTR) end of the mRNA transcript. A G to A mutation was described by Bohlen et al.
Sources: en.wikipedia.org
Reconstituted solutions are typically kept refrigerated at two to eight degrees Celsius when used within a short window, or frozen in aliquots for longer periods. Repeated freeze-thaw cycles are avoided because they can reduce recovery of intact peptide.
It establishes that the measured mass matches the expected value for the intact molecule. It also helps detect modifications such as oxidation or truncation that shift the mass by a known amount.
Cycling between frozen and liquid states can promote aggregation and adsorption to container walls. Dividing a stock into single-use aliquots limits the number of cycles a given vial undergoes.
It is a 28-amino-acid peptide originally purified from a bovine thymic extract and later produced synthetically. It is studied mainly for its effects on immune cell function.