This is a working overview of RP-HPLC, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-08. Anything still debated is marked as such rather than presented as settled.
The molecule consists of 28 amino acid residues with an acetyl group attached to the N-terminal serine. Its sequence is acidic overall, with several glutamic and aspartic acid residues distributed along the chain and no cysteine, so disulfide bridges do not form. The peptide carries a net negative charge at physiological pH. Because the N-terminus is blocked, the intact molecule resists degradation by many aminopeptidases, which contributes to its stability in biological fluids.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
Thymosin alpha 1 is a short peptide first isolated from bovine thymus tissue in the early 1970s during fractionation work aimed at identifying factors that influence T cell development. It belongs to a family of acidic thymic peptides, and the original preparations contained several components that were later separated by chromatography. The compound is now produced synthetically rather than extracted from tissue, which removes batch variability tied to animal sourcing. Researchers describe it as an immunomodulatory peptide because laboratory studies show effects on several cell types of the innate and adaptive immune systems.
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。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Acetylated peptide | N-terminal acetyl group blocks aminopeptidase attack |
| Residue count | 28 amino acids | Matches the N-terminus of prothymosin alpha |
| Molecular mass | About 3,108 Da | Value for the free, unmodified peptide |
| Isoelectric point | Approximately 4.2 | Acidic; net negative charge at neutral pH |
| Encoding gene | PTMA | Human gene for the precursor protein |
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.
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.
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.
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
The compound has been investigated as an adjunct in chronic viral hepatitis and as a vaccine adjuvant, with results that vary by study design and population. Regulators in some countries have approved a synthetic form for specific indications, while other agencies have not. Whether the peptide produces consistent clinical benefit across diverse patient groups is still an open question, and many trials have been small. Its status is therefore best described as investigational in many contexts and established only narrowly.
The name itself causes confusion, because several unrelated thymic peptides share the thymosin label. Thymosin beta-4, for example, is a different molecule with different functions. Naming conventions in the literature also mix descriptive research terms with assigned nonproprietary names, so a reader should confirm which entity a given paper addresses. Clarifying that point is usually the first step in interpreting any claim about this peptide.
March 4–5 – The Senate and House of Representatives reject War Powers Resolutions to halt Trump's actions in the 2026 Iran War without congressional approval. March 5–17 – The 2026 World Baseball Classic is held in the United States, including Puerto Rico, as well as in Japan. The championship game is held at LoanDepot Park in Miami.
Ansuvimab, sold under the brand name Ebanga, is a monoclonal antibody medication used for the treatment of Ebolavirus (Zaire ebolavirus) infection. The most common symptoms include fever, tachycardia (fast heart rate), diarrhea, vomiting, hypotension (low blood pressure), tachypnea (fast breathing) and chills; however, these are also common symptoms of Ebolavirus infection. Ansuvimab was approved for medical use in the United States in December 2020. It is on the World Health Organization's List of Essential Medicines. Ansuvimab is composed of a single monoclonal antibody (mAb) and was initially isolated from immortalized B-cells that were obtained from a survivor of the 1995 outbreak of Ebola virus disease in Kikwit, Democratic Republic of the Congo. In work supported by the United States National Institutes of Health and the Defense Advanced Projects Agency, the heavy and light chain sequences of ansuvimab mAb were cloned into Chinese hamster ovary cell lines and initial production runs were produced by Cook Phamica d.b.a. Catalent under contract with Medimmune.
There was initial resistance to these results on the part of Ernst Antevs, the palaeobotanist who had worked on the Scandinavian varve series, but his objections were eventually discounted by other geologists. In the 1990s samples were tested with AMS, yielding (uncalibrated) dates ranging from 11,640 BP to 11,800 BP, both with a standard error of 160 years. Subsequently, a sample from the fossil forest was used in an interlaboratory test, with results provided by over 70 laboratories. These tests produced a median age of 11,788 ± 8 BP (2σ confidence) which when calibrated gives a date range of 13,730 to 13,550 cal BP. The Two Creeks radiocarbon dates are now regarded as a key result in developing the modern understanding of North American glaciation at the end of the Pleistocene.
=== Environmental agents === Teratogens are environmental agents that cause birth defects. Some agents that are theorized to cause birth defects have also been suggested as potential autism risk factors, although there is little to no scientific evidence to back such claims. These include exposure of the embryo to valproic acid, thalidomide or misoprostol. These cases are rare. Questions have also been raised whether ethanol (grain alcohol) increases autism risk, as part of fetal alcohol syndrome or alcohol-related birth defects. All known teratogens appear to act during the first eight weeks from conception, and though this does not exclude the possibility that autism can be initiated or affected later, it is strong evidence that autism arises very early in development.
The Colombia national football team (Spanish: Selección de fútbol de Colombia), nicknamed Los Cafeteros, represents Colombia in men's international association football. It is administered by the Colombian Football Federation (Spanish: Federación Colombiana de Fútbol), the governing body for football in Colombia. The federation has been affiliated with FIFA and CONMEBOL since 1936. Colombia have appeared at seven FIFA World Cups, first qualifying for the 1962 FIFA World Cup. Their best performance came at the 2014 FIFA World Cup, where they reached the quarter-finals for the first time; James Rodríguez won the Golden Boot after scoring six goals. Colombia have also reached the knockout stage at the 1990, 2018 and 2026 tournaments. Colombia won the 2001 Copa América as hosts, winning all six matches without conceding a goal. The team has also finished as runners-up in 1975 and 2024, and third in 1987, 1993, 1995, 2016 and 2021.
Sources: en.wikipedia.org
Familial intrahepatic cholestasis (FIH) is a group of disorders that lead to intrahepatic cholestasis in children. Most often, FIH occurs during the first year of life, with an incidence rate of 1/50,000 to 1/100,000. There are three different versions of FIH, with each causing a different severity of jaundice. Typically, children exhibit recurrent jaundice episodes, which eventually become permanent. Diagnosis usually occurs by analyzing laboratory features, liver biopsy results, DNA/RNA sequences, and biliary lipid analysis. The definitive treatment for FIH is liver transplant which usually results in a high recovery rate. Each type of FIH is a result of a different mutation. The three genes thought to be involved include APT8B1, which encodes for the FIC1 protein. The ABCB11 gene encodes for the bile salt export pump (BSEP) protein, and the ABCB4 gene encodes for the multidrug resistance 3 (MDR3) protein. BSEP and MDR3 are respectively responsible for transporting bile salt and phospholipid, two major constituents of bile, across the apical membrane of hepatocytes.
== Function == As well as C. maenas, CCAP has cardioacceleratory properties in Manduca sexta and Drosophila melanogaster; it is a highly conserved protein found in species as diverse as moths and fruit flies in addition to the crustacean it was originally identified in. Under specific conditions, CCAP has also been shown to induce cardiac reversal in M. sexta and D. melanogaster. Since CCAP was first identified and its possible role suggested, it has been proven it serves many other functions. It regulates release of adipokinetic hormone during sustained flight in L. migratoria. It is also important in metabolism and digestion in other species; CCAP is involved as a hormone in the cockroach Periplaneta americana by upregulating digestive hormones after the insect has fed on nutritional matter. In the crab Cancer borealis CCAP controls passage of food through the foregut by modulating the stomatogastric ganglion's pyloric rhythm. This suggests CCAP is involved primarily in movement of food along the gut, facilitating digestion by secretion of digestive hormones and increasing flow of blood. The effects of CCAP on the reproductive organs of females of the species L. migratoria have also been studied. The peptide stimulates the contraction of the oviducts and spermatheca. There is no CCAP or CCAP-like immunoreactivity shown in the oviduct or the nerves innervating the oviduct so it is probable that CCAP acts as a neurohormone to perform these functions. CCAP is one of several peptides and hormones to be involved in the moulting process of crustaceans and insects.
== Epigenetics == The MTHFR aberrant promoter hypermethylation is associated with male infertility. Furthermore, this improper epigenetic phenomenon was observed in semen samples of infertile males belonging to couples with a history of recurrent spontaneous abortion. The MTHFR improper promoter hypermethylation may affect the two essential roles of DNA methylation in spermatogenetic cells, the global genome methylation process and the genomic imprinting of paternal genes. In addition, MTHFR gene promoter hypermethylation has also been associated with methylation loss at H19 imprinted gene in semen samples from infertile males.
=== Random drug testing === Can occur at any time, usually when the investigator has reason to believe that a substance is possibly being used by the subject by behavior or immediately after an employee-related incident occurs during work hours. Testing protocol typically conforms to the national medical standard, candidates are given up to 120 minutes to reasonably produce a urine sample from the time of commencement (in some instances this time frame may be extended at the examiner's discretion).
Sources: en.wikipedia.org
In 1995, the Insurance Institute for Highway Safety (IIHS) began frontal offset crash tests. Also in the same year, Volvo introduced the world's first car with side airbags: the 850. In 1996, the European New Car Assessment Programme (Euro NCAP) was established to test new vehicles' safety performance and publish the results for vehicle shoppers' information. The NHTSA crash tests are presently operated and published as the U.S. branch of the international NCAP programme.
ASH1L (also called huASH1, ASH1, ASH1L1, ASH1-like, or KMT2H) is a histone-lysine N-methyltransferase enzyme encoded by the ASH1L gene located at chromosomal band 1q22. ASH1L is the human homolog of Drosophila Ash1 (absent, small, or homeotic-like). Ash1 was discovered as a gene causing an imaginal disc mutant phenotype in Drosophila. Ash1 is a member of the trithorax-group (trxG) of proteins, a group of transcriptional activators that are involved in regulating Hox gene expression and body segment identity. Drosophila Ash1 interacts with trithorax to regulate ultrabithorax expression. The human ASH1L gene spans 227.5 kb on chromosome 1, band q22. This region is rearranged in a variety of human cancers such as leukemia, non-Hodgkin's lymphoma, and some solid tumors. The gene is expressed in multiple tissues, with highest levels in brain, kidney, and heart, as a 10.5-kb mRNA transcript. Mutations in ASH1L in humans have been associated with autism, epilepsy, and intellectual disability.
== Personal life == Guillaume was married twice; first to Marlene Williams in 1955, with whom he had two sons. Guillaume's daughter was born in 1980. They divorced in 1984. He married Donna Brown in 1986. The couple had a daughter. He also fathered a daughter by a different mother, who was born in 1950. In 1999, Guillaume suffered a stroke while working on Sports Night at Walt Disney Studios in Burbank, California. The stroke was minor, causing relatively slight damage and little effect on his speech. After six weeks in the hospital, he underwent therapy consisting of walks and gym sessions.
=== Legal status === In September 2025, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Kyinsu, intended for treatment of type 2 diabetes mellitus. The applicant for this medicinal product is Novo Nordisk A/S. Insulin icodec/semaglutide was authorized for medical use in the European Union in November 2025.
Phenethylamine is a primary amine, the amino-group being attached to a benzene ring through a two-carbon, or ethyl group. It is a colourless liquid at room temperature that has a fishy odor, and is soluble in water, ethanol and ether. Its density is 0.964 g/ml and its boiling point is 195 °C. Upon exposure to air, it combines with carbon dioxide to form a solid carbonate salt. Phenethylamine is strongly basic, pKb = 4.17 (or pKa = 9.83), as measured using the HCl salt, and forms a stable crystalline hydrochloride salt with a melting point of 217 °C. Its experimental log P is 1.41.
Sources: en.wikipedia.org
Thymosin fraction 5 is a mixture of many peptides obtained from thymus tissue, while thymosin alpha 1 is a single defined 28-residue molecule. The two names appear together in older literature because the purified peptide was first obtained from that mixture.
The precursor, prothymosin alpha, is encoded by the PTMA gene in humans. The 28-residue peptide corresponds to the N-terminal segment released from that larger protein.
It is produced as a fragment of prothymosin alpha and is present in many tissues. Circulating concentrations are low, which makes routine measurement difficult.
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。