If you have been reading about systematic review and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Molecular mass | About 3.1 kDa | 28 residues, N-terminally acetylated |
| Appearance | White to off-white powder | Lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in aqueous buffers |
| Storage temperature | 2 to 8 °C | Protect from light and moisture |
| Common synonyms | Thymalfasin; Tα1 | Same peptide sequence |
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.
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.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Results across trials have been mixed, and several studies were small or conducted under differing protocols. Regulatory status varies by country, and the compound is not approved in every jurisdiction where it is studied. Evidence for any single indication should be read with attention to sample size and endpoint choice.
Thymosin alpha-1 is a 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
A tablet of micronized progesterone which is marketed under the brand name Luteina is indicated for sublingual administration in addition to vaginal administration and is available in Poland and Ukraine. A progesterone suppository which is marketed under the brand name Cyclogest is indicated for rectal administration in addition to vaginal administration and is available in Cyprus, Hong Kong, India, Malaysia, Malta, Oman, Singapore, South Africa, Thailand, Tunisia, Turkey, the United Kingdom, and Vietnam. An aqueous solution of progesterone complexed with β-cyclodextrin for subcutaneous injection is marketed under the brand name Prolutex in the Czech Republic, Hungary, Italy, Poland, Portugal, Slovakia, Spain, and Switzerland. A non-systemic topical gel formulation of progesterone for local application to the breasts to treat breast pain is marketed under the brand name Progestogel and is available in Belgium, Bulgaria, Colombia, Ecuador, France, Georgia, Germany, Hong Kong, Lebanon, Peru, Romania, Russia, Serbia, Switzerland, Tunisia, Venezuela, and Vietnam. It was also formerly available in Italy, Portugal, and Spain, but was discontinued in these countries. A progesterone intrauterine device was previously marketed under the brand name Progestasert and was available in Canada, France, the United States, and possibly other countries, but was discontinued. Progesterone vaginal rings are marketed under the brand names Fertiring and Progering and are available in Chile, Ecuador, and Peru.
The Moskovskaya Okruzhnaya Zheleznaya Doroga (orbital railway line) has formed a ring around Moscow's current downtown since 1903. However, this line was a non-electrified, locomotive-only railway before reconstruction into the MCC during the 2010s. The Moscow Central Circle is a 54-kilometer (34 mi) orbital urban rail transit line that encircles historic Moscow. This line was built alongside the Little Ring of the Moscow Railway, incorporating some of its tracks. The MCC was opened for passenger use on 10 September 2016. The MCC line is operated by the Moscow government-owned company MKZD through the Moscow Metro, with the federal government-owned Russian Railways as the operations subcontractor.
Subsequent activation of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid), NMDA (N-methyl-D-aspartate) and kainate subtypes of ionotropic glutamate receptors follows. It is the activation of these receptors that potentiates the pain signal up the spinal cord. This idea, although true, is an oversimplification of pain transduction. A litany of other neurotransmitter and neuromodulators, such as calcitonin gene-related peptide (CGRP), adenosine triphosphate (ATP), brain-derived neurotrophic factor (BDNF), somatostatin, vasoactive intestinal peptide (VIP), galanin, and vasopressin are all synthesized and released in response to noxious stimuli. In addition to each of these regulatory factors, several other interactions between pain-transmitting neurons and other neurons in the dorsal horn have added impact on pain pathways.
TATP has been used in bomb and suicide attacks and in improvised explosive devices, including the London bombings on 7 July 2005, where four suicide bombers killed 52 people and injured more than 700. It was one of the explosives used by the "shoe bomber" Richard Reid in his 2001 failed shoe bomb attempt and was used by the suicide bombers in the November 2015 Paris attacks, 2016 Brussels bombings, Manchester Arena bombing, June 2017 Brussels attack, Parsons Green bombing, the Surabaya bombings, and the 2019 Sri Lanka Easter bombings. Hong Kong police claim to have found 2 kg (4.4 lb) of TATP among weapons and protest materials in July 2019, when mass protests were taking place against a proposed law allowing extradition to mainland China. TATP shockwave overpressure is 70% of that for TNT, and the positive phase impulse is 55% of the TNT equivalent. TATP at 0.4 g/cm3 has about one-third of the brisance of TNT at 1.2 g/cm3 as measured by the Hess test. TATP is attractive to terrorists because it is easily prepared from readily available retail ingredients like hair bleach and nail polish remover. It was also able to evade detection because it is one of the few high explosives which does not contain nitrogen, and could therefore pass undetected through standard explosive detection scanners, which were hitherto designed to detect nitrogenous explosives. By 2016, explosives detectors had been modified to be able to detect TATP, and new types were developed.
== Types and examples == The most important progestogen in the body is progesterone (P4). Other endogenous progestogens, with varying degrees of progestogenic activity, include 16α-hydroxyprogesterone (16α-OHP), 17α-hydroxyprogesterone (17α-OHP) (very weak), 20α-dihydroprogesterone (20α-DHP), 20β-dihydroprogesterone (20β-DHP), 5α-dihydroprogesterone (5α-DHP), 5β-dihydroprogesterone (5β-DHP) (very weak), 3β-dihydroprogesterone (3β-DHP), 11-deoxycorticosterone (DOC), and 5α-dihydrodeoxycorticosterone (5α-DHDOC). They are all metabolites of progesterone, lying downstream of progesterone in terms of biosynthesis.
Sources: en.wikipedia.org
Current issues for the CV reside in outbreaks of violence with criminal organizations for control of drug routes and turf wars with militias over territories, such as the Complexo do Alemão (which is sometimes considered the "headquarters" of the organization).
== History == Gramicidin S was discovered by Russian microbiologist Georgyi Frantsevitch Gause and his wife Maria Brazhnikova in 1942. Within the year Gramicidin S was being used in Soviet military hospitals to treat infection and eventually found usage at the front lines of combat by 1946. Gause was awarded the Stalin Prize for Medicine for his discovery in 1946. In 1944, Gramicidin S was sent by the Ministry of Health of the USSR to Great Britain via the International Red Cross in a collaborative effort to establish the exact structure. English chemist Richard Synge proved that the compound was an original antibiotic and a polypeptide using paper chromatography. He would later go on to receive the Nobel Prize for his work in chromatography. The crystal structure was finally established by Dorothy Hodgkin and Gerhard Schmidt; Margaret Thatcher worked for a term in 1947 with Gerhard Schmidt on the antibiotic Gramicidin S, as an undergraduate research project. The importance of Gramicidin S and antibiotic research in general was so great that Gause was not persecuted during the period of Lysenkoism in the USSR, while many of his colleagues were. Indeed, it was his need for developing new strains to mass-produce antibiotics that allowed politically sanctioned collaborations with geneticists like Joseph Rapoport and Alexander Malinovsky, who would both actively participate in the downfall of Lysenkoism.
The mammalian excretory system involves many components. Like amphibians, mammals are ureotelic, and convert ammonia into urea, which is done by the liver as part of the urea cycle. Bilirubin, a waste product derived from blood cells, is passed through bile and urine with the help of enzymes excreted by the liver. The passing of bilirubin via bile through the intestinal tract gives mammalian feces a distinctive brown coloration. Distinctive features of the mammalian kidney include the presence of the renal pelvis and renal pyramids, and of a clearly distinguishable cortex and medulla, which is due to the presence of elongated loops of Henle. Only the mammalian kidney has a bean shape, although there are some exceptions, such as the multilobed reniculate kidneys of pinnipeds, cetaceans and bears. Most adult placentals have no remaining trace of the cloaca. In the embryo, the embryonic cloaca divides into a posterior region that becomes part of the anus, and an anterior region that has different fates depending on the sex of the individual: in females, it develops into the vestibule or urogenital sinus that receives the urethra and vagina, while in males it forms the entirety of the penile urethra. However, the afrosoricids and some shrews retain a cloaca as adults. In marsupials, the genital tract is separate from the anus, but a trace of the original cloaca does remain externally. Monotremes, which translates from Greek into "single hole", have a true cloaca. Urine flows from the ureters into the cloaca in monotremes and into the bladder in placentals.
Although Barker had previously worked with White, he was feuding with her over the treatment of an elephant at the Los Angeles Zoo. White instead did not attend and pre-recorded her comments that she was scheduled to make about another awardee, Mark Goodson. That same year, Barker donated $1 million (equivalent to $1.4 million in 2021) to the University of Virginia Law School to support the study of animal rights. He made similar donations to Harvard Law School, Stanford Law School, Georgetown University Law Center, Duke University School of Law, Northwestern University Pritzker School of Law, and University of California, Los Angeles. In 2010, the Sea Shepherd Conservation Society announced that it had purchased and outfitted a ship to interdict Japanese whaling operations in the Southern Ocean using $5 million (equivalent to $7.4 million in 2025) provided by Barker. The ship was then named the MY Bob Barker, and its existence was first revealed when it helped discover the location of the Japanese whaling fleet. Barker participated in several PETA public service announcements over the years, including one that claimed that vegetarian diets prevent Alzheimer's disease. In 2010, he donated $2.5 million (equivalent to $3.7 million in 2025) toward the purchase of office space for the organization in Los Angeles. The Bob Barker Building opened in 2012.
Sources: en.wikipedia.org
While some diseases like lupus exhibit familial aggregation, suggesting a genetic predisposition, other cases have been associated with infectious triggers or exposure to environmental factors, implying a complex interplay between genes and environment in their etiology. Some of the most common diseases that are generally categorized as autoimmune include coeliac disease, type 1 diabetes, Graves' disease, inflammatory bowel diseases (such as Crohn's disease and ulcerative colitis), multiple sclerosis, alopecia areata, Addison's disease, pernicious anemia, psoriasis, rheumatoid arthritis, and systemic lupus erythematosus. Diagnosing autoimmune diseases can be challenging due to their diverse presentations and the transient nature of many symptoms. Treatment modalities for autoimmune diseases vary based on the type of disease and its severity. Therapeutic approaches primarily aim to manage symptoms, reduce immune system activity, and maintain the body's ability to fight diseases. Nonsteroidal anti-inflammatory drugs (NSAIDs) and immunosuppressants are commonly used to reduce inflammation and control the overactive immune response. In certain cases, intravenous immunoglobulin may be administered to regulate the immune system. Despite these treatments often leading to symptom improvement, they usually do not offer a cure and long-term management is often required. In terms of prevalence, a UK study found that 10% of the population were affected by an autoimmune disease. Women are more commonly affected than men.
=== Pregnancy === Methocarbamol is labeled by the FDA as a pregnancy category C medication. The teratogenic effects of the medication are not known and it should be given to pregnant women only when indicated.
On the same day, the talks between the US and Iran—the highest-level discussions between the two since the 1979 Islamic Revolution—were held in Islamabad, Pakistan, lasting 21 hours. JD Vance announced no agreement was reached and Iran had refused "to accept our terms". Trump stated he no longer cared about negotiations. Trump declared that the US Navy would begin its blockade of "all Ships trying to enter, or leave, the Strait of Hormuz" from 13 April. He said the US Navy would stop any ships that paid tolls to Iran. However, United States Central Command clarified that the blockade would only be enforced on ships traveling to or from Iranian ports. The IRGC Navy said any military vessel approaching the strait would be considered a ceasefire violation and meet a "severe response." Trump threatened to strike fast-attack ships of the IRGC Navy, similar to US strikes on drug traffickers during Operation Southern Spear. Iran had 13 days of oil storage capacity, forcing it to shut down its oil fields and potentially damaging them. An analyst estimated loss of import and export capacity would be US$435 million per day. On 16 April, Trump announced that Israel and Lebanon agreed to a ten-day truce. Iran announced that passage of commercial vessels through the strait would be allowed during the truce, however, Trump said that the blockade would continue, with Iran reimposing restrictions on the strait. The US stated that its blockade had intercepted 23 ships. Despite Iran's seizure of two cargo ships, Trump claimed total control over the strait.
==== Pilosan research ==== Casali et al. (2026) identify a poorly developed dental alveolus in a specimen of Nothrotherium maquinense from the Pleistocene strata from Brazil, occupying the position of caniniform alveolus in Neogene nothrotheriids, and interpreted as a possible case of partial re-expression of a lost ancestral dental condition in the studied individual. Revision of nematheriine scelidotheriid sloths from the Miocene Santa Cruz Formation (Argentina) is published by Boscaini et al. (2026), who assign all studied fossils to the genus Nematherium, with the majority of them assigned to the species N. angulatum New fossil material of Ocnotherium giganteum, including a nearly complete skull and two partial skeletons, is described from the Pleistocene strata from Brazil by Pujos et al. (2026), who recover O. giganteum as a mylodontine mylodontid. Evidence from the study of a mylodontid coprolite from the Pleistocene strata from the Cueva Cacao 1.A site (Argentina) indicative of a grazing-browsing dietary niche of the producer is presented by Velázquez et al. (2026). Zicos et al. (2026) compare the utility of three ancient DNA extraction methods for recovery of DNA from coprolites of Mylodon darwinii and soil samples from Cueva del Milodón (Chile), and report recovery of both sloth mitochondrial genomes and signatures of local flora. Harper et al.
=== Role in wound healing === Macrophages are essential for wound healing. They replace polymorphonuclear neutrophils as the predominant cells in the wound by day two after injury. Attracted to the wound site by growth factors released by platelets and other cells, monocytes from the bloodstream enter the area through blood vessel walls. Numbers of monocytes in the wound peak one to one and a half days after the injury occurs. Once they are in the wound site, monocytes mature into macrophages. The spleen contains half the body's monocytes in reserve ready to be deployed to injured tissue. The macrophage's main role is to phagocytize bacteria and damaged tissue, and they also debride damaged tissue by releasing proteases. Macrophages also secrete a number of factors such as growth factors and other cytokines, especially during the third and fourth post-wound days. These factors attract cells involved in the proliferation stage of healing to the area. Macrophages may also restrain the contraction phase. Macrophages are stimulated by the low oxygen content of their surroundings to produce factors that induce and speed angiogenesis and they also stimulate cells that re-epithelialize the wound, create granulation tissue, and lay down a new extracellular matrix. By secreting these factors, macrophages contribute to pushing the wound healing process into the next phase.
Sources: en.wikipedia.org
It is a 28-residue synthetic peptide studied as an immune-modulating agent and approved as a drug in some countries. The sequence matches a naturally occurring fragment isolated from thymus tissue. It is not a hormone in the endocrine sense.
The name traces back to thymosin fraction 5, a crude thymus extract examined in the 1970s. Individual peptides in that mixture were labeled with Greek letters, and alpha-1 was one of them. The international nonproprietary name thymalfasin was assigned later.
No. Thymosin beta-4 contains 43 residues and binds actin, while thymosin alpha-1 contains 28 residues and acts on immune cells. The two sit in a historical naming group but share no sequence similarity, and they are not substitutes for one another.
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。