The short version of reverse-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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。
胸腺素α1对免疫系统的影响涉及多种细胞类型。研究表明，它可促进未成熟T细胞向成熟T细胞分化，并增强T细胞对抗原刺激的增殖反应。树突状细胞在Tα1存在下表达更高水平的共刺激分子，从而更有效地呈递抗原。此外，自然杀伤细胞的活性也观察到上升。这些效应并非直接杀伤病原体，而是调节宿主免疫应答的强度与方向。
Several factors accelerate degradation: alkaline pH, elevated temperature, exposure to oxidants, and the presence of residual moisture. Deamidation of asparagine residues and oxidation of methionine are the most commonly reported degradation routes. Because the peptide lacks disulfide bonds, it does not undergo the thiol-related aggregation seen in some other biologics, but physical aggregation can still occur at high concentration. Stability data are product-specific, and extrapolating shelf life between formulations is not reliable.
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
| Property | Value | Notes |
|---|---|---|
| 主要靶细胞 | T细胞、树突状细胞 | 也影响NK细胞 |
| 信号通路 | TLR/MyD88/NF-κB | 部分实验模型 |
| 细胞因子偏向 | Th1型 | 增加IL-2、IFN-γ |
| 给药途径 | 皮下注射 | 临床常用 |
| 半衰期 | 约2小时 | 血浆中较短 |
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
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.
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.
Lyophilized material is generally held at reduced temperature to slow degradation, and storage at minus twenty degrees Celsius or lower is common practice for long-term retention. Short-term working portions are often kept between two and eight degrees Celsius. Once dissolved, the peptide is less stable than the dry powder, and repeated freeze-thaw cycles are associated with loss of material and with aggregate formation. Vials are usually allowed to reach room temperature before opening so that condensation does not introduce moisture, and solutions are protected from light where practical.
Identity and purity are usually checked by reverse-phase high-performance liquid chromatography, which separates the intact chain from truncated products, together with mass spectrometry for confirmation of the expected mass. Peptide mapping after enzymatic digestion and amino acid analysis add sequence-level evidence. Release testing also covers water content, residual solvents, and counter-ions, all of which influence measured mass and stability. Related-peptide limits are commonly expressed as a percentage of total peak area, with individual unspecified impurities held below a lower threshold.
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.
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.
=== Yeast and bacteria === Unlike humans, yeast and bacteria (except lactic acid bacteria, and E. coli in certain conditions) do not ferment glucose to lactate. Instead, they ferment it to ethanol and CO2. The overall reaction can be seen below:
=== Enzymes === Peripheral enzymes participate in metabolism of different membrane components, such as lipids (phospholipases and cholesterol oxidases), cell wall oligosaccharides (glycosyltransferase and transglycosidases), or proteins (signal peptidase and palmitoyl protein thioesterases). Lipases can also digest lipids that form micelles or nonpolar droplets in water.
== Examples == Only two elements are liquid at standard conditions for temperature and pressure: mercury and bromine. Four more elements have melting points slightly above room temperature: francium, caesium, gallium and rubidium. Pure substances that are liquid under normal conditions include water, ethanol and many other organic solvents. Liquid water is of vital importance in chemistry and biology, and it is necessary for all known forms of life. Inorganic liquids in this category include inorganic nonaqueous solvents and many acids. Mixtures that are liquid at room temperature include alloys such as galinstan (a gallium-indium-tin alloy that melts at −19 °C or −2 °F) and some amalgams (alloys involving mercury). Certain mixtures, such as the sodium-potassium metal alloy NaK, are liquid at room temperature even though the individual elements are solid under the same conditions (see eutectic mixture). Everyday liquid mixtures include aqueous solutions like household bleach, other mixtures of different substances such as mineral oil and gasoline, emulsions like vinaigrette or mayonnaise, suspensions like blood, and colloids like paint and milk. Many gases can be liquefied by cooling, producing liquids such as liquid oxygen, liquid nitrogen, liquid hydrogen and liquid helium. However, not all gases can be liquefied at atmospheric pressure. Carbon dioxide, for example, solidifies directly into dry ice rather than becoming a liquid, and it can only be liquified at pressures above 5.1 atm. Most liquids solidify as the temperature is decreased further.
The United States accused Maduro of electoral fraud and presiding over a "narco-state". In March 2020, during Trump's first term, the United States Justice Department indicted Maduro on cocaine-trafficking conspiracy charges, which Maduro denied. Trump designated two Venezuelan drug gangs, the Tren de Aragua and the Cartel of the Suns, as Foreign Terrorist Organizations (FTOs) in January and July 2025 respectively, and alleged that the latter was led by Maduro. Maduro denied being involved in cartel leadership and characterized the designations as an attempt to use the war on drugs for regime change. Some Latin American crime experts have described the Cartel of the Suns as more of a general network of Venezuelan government and military corruption than as an organized group. Also in July 2025, a secret order instructed the US military to use force against cartels listed as terrorist organizations. In August 2025, the reward for Maduro's arrest increased to $50 million with US attorney general Pam Bondi calling Maduro "one of the largest narco-traffickers in the world and a threat to our national security." However, the Associated Press reported in January 2026 that while the US government has never publicly accused Delcy Rodríguez of criminal wrongdoing related to the drug trade, the Drug Enforcement Administration has nonetheless gathered an extensive intelligence file on Rodríguez since 2018 and designated her as a "priority target" in 2022—which the agency does for individuals suspected of having "significant impact" on the drug trade.
Bird said he was not trying to sabotage Clark's effort. He said he merely had told several witnesses for the state that "I don't think you should jeopardize your reputation with the way [the trial] is being handled." Clark stated he was considering legal action against Bird, whose actions, he said, were "tantamount to tampering with justice."
Sources: en.wikipedia.org
Guidelines released by the Clinical Pharmacogenomics Implementation Consortium (CPIC) advise against administering codeine to ultrarapid metabolizers, where this genetic information is available. The CPIC also suggests that codeine use be avoided in poor metabolizers, due to its lack of efficacy in this group. Codeine and its salts are readily absorbed from the gastrointestinal tract, and ingestion of codeine phosphate produces peak plasma concentrations in about one hour. Plasma half life is between 3 and 4 hours, and oral/intramuscular analgesic potency ratio is approximately equal to 1:1.5. The most common conversion ratio, given on equianalgesia charts used in the United States, Canada, the UK, Republic of Ireland, the European Union, Russia and elsewhere as 130 mg IM equals 200 mg PO—both of which are equivalent to 10 mg of morphine sulphate IV and 60 mg of morphine sulphate PO. The salt:freebase ratio of the salts of both drugs in use are roughly equivalent, and do not generally make a clinical difference. Codeine is metabolised by O- and N-demethylation in the liver to morphine and norcodeine. Hydrocodone is also a metabolite of codeine in humans. Codeine and its metabolites are mostly removed from the body by the kidneys, primarily as conjugates with glucuronic acid. The active metabolites of codeine, notably morphine, exert their effects by binding to and activating the μ-opioid receptor. People that can metabolize codeine to an extensive degree could result in a 30 mg dose yielding 4 mg of morphine.
Many countries have stockpiled first generation smallpox vaccines. In a 2006 predictive analysis of casualties if there were a mass vaccination of the populations of Germany and the Netherlands, it was estimated that a total of 9.8 people in the Netherlands and 46.2 people in Germany would die from uncontrolled vaccinia infection after being vaccinated with the New York City Board of Health strain. More deaths were predicted for vaccines based other strains: Lister (55.1 Netherlands, 268.5 Germany) and Bern (303.5 Netherlands, 1,381 Germany).
=== Sales === The Xbox 360 version was the third best-selling game of August 2007, with 490,900 copies. The Wall Street Journal reported that shares in Take-Two Interactive "soared nearly 20%" in the week following overwhelmingly favorable early reviews of the game. Take-Two Interactive announced that by June 5, 2008, over 2.2 million copies of BioShock had been shipped. In a June 10, 2008 interview, Roy Taylor, Nvidia's VP of Content Business Development, stated that the PC version has sold over one million copies. According to Take-Two Interactive's chairman Strauss Zelnick, the game had sold around 3 million copies by June 2009. By March 2010, BioShock had sold 4 million copies, with the release of its sequel, BioShock 2, boosting sales of the original game.
==== College of Interdisciplinary and Continuing Studies ==== The College of Interdisciplinary and Continuing Studies provides degree programs to learners with previously earned college credits but no degree, affording the opportunity of degree completion. The interdisciplinary nature of the programs allows students to draw from expertise and resources across campus to design a program of study aligned with local, national and global workforce opportunities.
== Limitations == Although well ordered nanostructures have already been successfully formed from self-assembling peptides, their potential will not be fully fulfilled until useful functionality is incorporated into the structures. Moreover, so far most of the peptide structures formed are in one or two dimensions. In contrast, in nature, most biological structures are in three dimensions. Criticism has come because there is a lack of theoretical knowledge about the self-assembling behaviours of peptides. Further knowledge could prove to be very useful in facilitating rational designs and precise control of the peptide assemblies. Lastly, although an extensive amount of work is being conducted on developing self-assembling peptide-related applications, issues such as commercial viability and processability have not been paid the same amount of attention. Yet these issues must be assessed if further useful applications are to be realized.
Sources: en.wikipedia.org
The study of proteins in vivo is often concerned with the synthesis and localization of the protein within the cell. Although many intracellular proteins are synthesized in the cytoplasm and membrane-bound or secreted proteins in the endoplasmic reticulum, the specifics of how proteins are targeted to specific organelles or cellular structures is often unclear. A useful technique for assessing cellular localization uses genetic engineering to express in a cell a fusion protein or chimera consisting of the natural protein of interest linked to a "reporter" such as green fluorescent protein (GFP). The fused protein's position within the cell can then be cleanly and efficiently visualized using microscopy. Other methods for elucidating the cellular location of proteins requires the use of known compartmental markers for regions such as the ER, the Golgi, lysosomes or vacuoles, mitochondria, chloroplasts, plasma membrane, etc. With the use of fluorescently tagged versions of these markers or of antibodies to known markers, it becomes much simpler to identify the localization of a protein of interest. For example, indirect immunofluorescence will allow for fluorescence colocalization and demonstration of location. Fluorescent dyes are used to label cellular compartments for a similar purpose. Other possibilities exist, as well. For example, immunohistochemistry usually uses an antibody to one or more proteins of interest that are conjugated to enzymes yielding either luminescent or chromogenic signals that can be compared between samples, allowing for localization information.
==== Antipseudomonal antibiotics ==== The Gram-negative species, Pseudomonas aeruginosa, is naturally resistant to many antibiotic classes. There were many efforts in the 1960s and 1970s to develop antibiotics that are active against Pseudomonas species. There are two chemical classes within the group: carboxypenicillins and ureidopenicillins. All are given by injection: none can be given by mouth.
In cosmetic applications, botulinum toxin is considered relatively safe and effective for reduction of facial wrinkles, especially in the uppermost third of the face. Commercial forms are marketed under the brand names Botox Cosmetic/Vistabel from Allergan, Dysport/Azzalure from Galderma and Ipsen, Xeomin/Bocouture from Merz, Jeuveau/Nuceiva from Evolus, manufactured by Daewoong in South Korea. The effects of botulinum toxin injections for glabellar lines ("11's lines" between the eyes) typically last two to four months and in some cases, product-dependent, with some patients experiencing a longer duration of effect of up to six months or longer. Injection of botulinum toxin into the muscles under facial wrinkles causes relaxation of those muscles, resulting in the smoothing of the overlying skin. Smoothing of wrinkles is usually visible three to five days after injection, with maximum effect typically a week following injection. Muscles can be treated repeatedly to maintain the smoothed appearance. DaxibotulinumtoxinA (Daxxify) was approved for medical use in the United States in September 2022. It is indicated for the temporary improvement in the appearance of moderate to severe glabellar lines. DaxibotulinumtoxinA is an acetylcholine release inhibitor and neuromuscular blocking agent. The FDA approved daxibotulinumtoxinA based on evidence from two clinical trials (Studies GL-1 and GL-2), of 609 adults with moderate to severe glabellar lines. The trials were conducted at 30 sites in the United States and Canada.
== Clinical significance == PAT1 mRNA is expressed in the GI tract between the stomach and descending colon, but is generally absent in the esophagus, caecum, and rectum. This allows for different treatments that affect the affinity of the carrier protein for its substrates, giving the potential to treat various amino-acid related diseases. HPAT1 and HPAT2 are important in the absorption of certain drugs, especially pharmaceutically active amino acids derivatives. They have also been targeted with medications used as anticonvulsants, for prostate cancer, and for bladder cancer. HPAT1 and 2 are integral to the central nervous system because they transport GABA and its analogues which can induce and inhibitory and excitatory effect in the brain.
Sources: en.wikipedia.org
它促进未成熟T细胞分化并增强成熟T细胞的增殖与细胞因子分泌。这些作用有助于放大抗原特异性免疫应答。
目前认为它可能通过Toll样受体等模式识别受体传递信号，但精确的受体身份和结合机制尚未完全阐明。
不同试验在患者选择、给药方案、联合治疗和终点定义上差异很大。这些异质性使得跨研究比较困难，结论难以统一。
Dry lyophilized powder tolerates short ambient exposure during handling and shipping. Long-term room-temperature storage is not recommended because moisture uptake and slow degradation can occur over months. Storage at minus twenty degrees Celsius is the common practice for extended periods.