The short version of prothymosin alpha fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-27 and is reviewed periodically as new material appears.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids whose sequence matches the amino-terminal region of prothymosin alpha. The chain is acetylated at its first residue and contains one disulfide bridge between two cysteine residues, which folds the molecule into a compact loop. Its molecular formula, C129H215N33O55, corresponds to a monoisotopic mass of roughly 3,106 daltons. Material used in laboratories is made by solid-phase synthesis rather than isolated from animal tissue.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
Like most short peptides, thymosin alpha-1 is susceptible to hydrolysis under strongly acidic or basic conditions and to oxidation when exposed to air over long periods. The acetylated amino terminus blocks one common degradation route, which contributes to the molecule's relative robustness in solution. Lyophilized material generally retains potency for extended periods when kept cold and dry. Once reconstituted, aqueous solutions are less stable and are typically used within a defined window rather than held indefinitely at ambient temperature.
Routine handling calls for storage of the lyophilized powder at refrigerated temperatures, away from light, in a sealed container. Working solutions are often prepared in sterile water or buffer and kept cold between uses. Repeated freeze-thaw cycles are generally avoided because they can promote aggregation and loss of material. Laboratories usually record lot number, reconstitution date, and storage conditions so that any change in behavior can be traced to a specific preparation.
| Property | Value | Notes |
|---|---|---|
| Class | Synthetic peptide | 28 residues; not a small-molecule compound |
| Molecular mass | About 3,106 Da | Monoisotopic mass of the unmodified chain |
| N-terminal group | Acetylated serine | Present in both native and synthetic forms |
| Secondary structure | Disulfide-constrained loop | One bridge between two cysteine residues |
| Typical source | Solid-phase synthesis | Early isolates came from bovine thymus extracts |
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.
Quantifying thymosin alpha-1 in a sample usually relies on reverse-phase high-performance liquid chromatography. The peptide lacks strong chromophores, so detection often occurs at 214 nm, where the peptide backbone absorbs. Mass spectrometry provides confirmatory identification and can detect sequence variants or truncations. Immunoassays have been used in biological matrices, but they may cross-react with related fragments. For purity assessment, chromatographic peak area gives the main component percentage, while mass accuracy verifies molecular identity.
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.
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。
== Astrophysical dating == Knowledge of current and theoretical production ratios of uranium-235 to uranium-238 allows radiometric dating, the time since modern uranium nuclei were formed in stellar nucleosynthesis. The 1957 B2FH landmark paper in astrophysics explained the r-process by which both nuclei form. The authors predicted their relative abundances, and those of their rapidly alpha-chain decaying parent nuclides. Thus they predicted 1.64 as the 235U/238U ratio contributed to the interstellar medium by r-process events (supernovae and subsequently discovered kilonovae). This takes billions of years to diminish to their present value of 0.0072 (see natural uranium). They investigate scenarios for historical contribution to the solar nebula, before contribution is cut off at the Sun's formation 4.5 billion years ago. The scenarios are: a single supernova, a finite continuous uniform series of supernovae representing the lifetime of the Milky Way, and an infinite series representing the steady-state universe. From the second scenario, they estimated an age of the Milky Way at around 10 billion years, compared to a modern value of 13.61 billion years. At the time, the oldest known objects were globular clusters, of which the oldest were estimated to be about 6.5 billion years old.
== Side effects and contraindications == The withdrawal of troglitazone has led to concerns of the other thiazolidinediones also increasing the incidence of hepatitis and potential liver failure, an approximately 1 in 20,000 individual occurrence with troglitazone. Because of this, the FDA recommends two to three month checks of liver enzymes for the first year of thiazolidinedione therapy to check for this rare but potentially catastrophic complication. To date, 2008, the newer thiazolidinediones, rosiglitazone and pioglitazone have been free of this problem. The main side effect of all thiazolidinediones is water retention, leading to edema, generally a problem in less than 5% of individuals, but a big problem for some and potentially, with significant water retention, leading to a decompensation of potentially previously unrecognized heart failure. Therefore, thiazolidinediones should be prescribed with both caution and patient warnings about the potential for water retention/weight gain, especially in patients with decreased ventricular function (NYHA grade III or IV heart failure). Though older studies suggested there may be an increased risk of coronary heart disease and heart attacks with rosiglitazone, pioglitazone treatment, in contrast, has shown significant protection from both micro- and macro-vascular cardiovascular events and plaque progression. These studies led to a period of Food and Drug Administration advisories (2007 – 2013) that, aided by extensive media coverage, led to a substantial decrease in rosiglitazone use.
==== Mycotoxins ==== In April 2014, aflatoxin B1, a known carcinogenic toxin, melamine, and cyanuric acid were all found in various brands of USA pet food imported into Hong Kong. Since 1993, the FDA has confirmed concerns of toxins in feed grade (animal grade) ingredients, yet to date no comprehensive federal regulation exists on mycotoxin testing in feed grade (animal grade) ingredients used to make pet food. In 1997, the Journal of Food Additives and Contaminants established that low levels of various mycotoxins could cause health concerns in pets, and was found in feed grade ingredients. A study published in the Journal of Food Protection in 2001 cited concerns regarding fungi (the source of mycotoxins) in commercial pet foods and warned about the "risk for animal health". In 2006, a study published in the Journal of Agricultural and Food Chemistry confirmed mycotoxins in pet foods around the world and concluded that contamination of mycotoxins in pet foods can lead to chronic effects on the health of pets. In 2007, the International Journal of Food Microbiology published a study that claimed "mycotoxin contamination in pet food poses a serious health threat to pets", and listed them: aflatoxins, ochratoxins, trichothecenes, zearalenone, fumonisins and fusaric acid. A 2008 study published in the Journal of Animal Physiology and Animal Nutrition found high levels of mycotoxins in the raw ingredients used for pet food in Brazil. A 2010 study in the Journal of Mycotoxin Research tested 26 commercial dog foods and found mycotoxins at concerning sub-lethal levels.
Sources: en.wikipedia.org
Bayer's original trade name of heroin is typically used in non-medical settings. It is used as a recreational drug for the euphoria it induces. Anthropologist Michael Agar once described heroin as "the perfect whatever drug." Tolerance develops quickly, and increased doses are needed in order to achieve the same effects. Its popularity with recreational drug users, compared to morphine, reportedly stems from its perceived different effects. Short-term addiction studies by the same researchers demonstrated that tolerance to heroin and morphine developed at a similar rate. When compared to the opioids hydromorphone, fentanyl, oxycodone, and pethidine (meperidine), former addicts showed a strong preference for heroin and morphine, suggesting that heroin and morphine are particularly susceptible to misuse and causing dependence. Morphine and heroin were also much more likely to produce euphoria and other positive subjective effects when compared to these other opioids. Heroin came into widespread use in South Africa in 2009 but the epidemic of heroin addiction has escalated since 2013 as prices have fallen rapidly in recent years. Heroin is primarily used by unemployed young men. Heroin generates intense feelings of euphoria, deep contentment, and relaxation. It also reduces appetite. Effects may last two to four hours. The drug can be inhaled after being warmed in a glass pipe but can be also smoked with cannabis in the form of a joint. It is primarily injected intravenously.
==== Open wounds ==== Incisions or incised wounds – caused by a clean, sharp-edged object such as a knife, razor, or glass splinter. Lacerations – irregular tear-like wounds caused by some blunt trauma. Lacerations and incisions may appear linear (regular) or stellate (irregular). The term laceration is commonly misused in reference to incisions. Abrasions (grazes) – superficial wounds in which the topmost layer of the skin (the epidermis) is scraped off. Abrasions are often caused by a sliding fall onto a rough surface such as asphalt, tree bark or concrete. Avulsions – injuries in which a body structure is forcibly detached from its normal point of insertion; a type of amputation where the extremity is pulled off rather than cut off. When used in reference to skin avulsions, the term 'degloving' is also sometimes used as a synonym. Puncture wounds – caused by an object puncturing the skin, such as a splinter, nail, knife or sharp tooth. Penetration wounds – caused by an object such as a knife entering and coming out from the skin. Gunshot wounds – caused by a bullet or similar projectile driving into or through the body. There may be two wounds, one at the site of entry and one at the site of exit, generally referred to as a "through-and-through." Critical wounds – Including large burns that have been split. These wounds can cause serious hydroelectrolytic and metabolic alterations including fluid loss, electrolyte imbalances, and increased catabolism.
=== Non-canonical/alternate pathway === A select set of cell-differentiating or developmental stimuli, such as lymphotoxin β-receptor (LTβR), BAFF or RANKL, activate the non-canonical NF-κB pathway to induce NF-κB/RelB:p52 dimer in the nucleus. In this pathway, activation of the NF-κB inducing kinase (NIK) upon receptor ligation led to the phosphorylation and subsequent proteasomal processing of the NF-κB2 precursor protein p100 into mature p52 subunit in an IKK1/IKKa dependent manner. Then p52 dimerizes with RelB to appear as a nuclear RelB:p52 DNA binding activity. RelB:p52 regulates the expression of homeostatic lymphokines, which instructs lymphoid organogenesis and lymphocyte trafficking in the secondary lymphoid organs. In contrast to the canonical signaling that relies on NEMO-IKK2 mediated degradation of IκBα, -β, -ε, non-canonical signaling depends on NIK mediated processing of p100 into p52. Given their distinct regulations, these two pathways were thought to be independent of each other. However, it was found that syntheses of the constituents of the non-canonical pathway, viz RelB and p52, are controlled by canonical IKK2-IκB-RelA:p50 signaling. Moreover, generation of the canonical and non-canonical dimers, viz RelA:p50 and RelB:p52, within the cellular milieu are mechanistically interlinked. These analyses suggest that an integrated NF-κB system network underlies activation of both RelA and RelB containing dimer and that a malfunctioning canonical pathway will lead to an aberrant cellular response also through the non-canonical pathway.
Sources: en.wikipedia.org
Pipradrol, also known by its brand name Meratran, is a mild central nervous system stimulant that acts as a norepinephrine-dopamine reuptake inhibitor. Developed in the United States in the 1940s and patented in 1953, pipradrol was initially marketed as an antidepressant in the mid-1950s. It was subsequently used as an adjunct treatment for various conditions, including obesity, senile dementia, narcolepsy, and schizophrenia. Despite its initial promise and relatively mild stimulant effects compared to stronger alternatives, concerns about its abuse potential led to its regulation and withdrawal from widespread use in many countries during the late 1970s. Pipradrol is now classified as a controlled substance in several nations, including the United Kingdom, where it is typically placed in less restrictive drug schedules due to its lower abuse potential compared to other stimulants.
=== Australia === An Australian edition was briefly published in early 2004, for less than six months. The Australian edition consisted mostly of content from the UK edition, along with news on the local games industry.
==== New Zealand ==== Rosiglitazone was withdrawn from the New Zealand market April 2011 because Medsafe concluded the suspected cardiovascular risks of the medicine for patients with type 2 diabetes outweigh its benefits.
Sources: en.wikipedia.org
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.
The single bridge between two cysteine residues holds the chain in a folded loop that influences its shape and its behavior in solution. Loss of the bridge through reduction or oxidation shifts chromatographic retention and is tracked during stability work.
It is a defined 28-residue sequence derived from a larger precursor, whereas many other thymic preparations are mixtures of several polypeptides. Its acetylated amino terminus and single disulfide bridge distinguish it chemically from unrelated thymic extracts.
The lyophilized solid is normally held at 2 to 8 °C in a sealed, light-protected container. Dry storage limits both hydrolysis and microbial growth. Material kept this way remains stable for the shelf life stated by the supplier.