The short version of actin-binding motif fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-08-05. Anything still debated is marked as such rather than presented as settled.
No major regulatory agency has approved TB-500 for therapeutic use, and it holds no pharmacopoeial monograph. The name appears on the World Anti-Doping Agency prohibited list within the class covering peptide hormones, growth factors, and related substances. Detection in doping control relies on mass spectrometric methods applied to urine, often after preparation steps that concentrate the analyte. Discussion of TB-500 therefore clusters in biochemistry, sports medicine, and anti-doping literature rather than in registered clinical trials.
TB-500 is a synthetic peptide preparation marketed under a name derived from thymosin beta-4, a 43-residue actin-binding protein first isolated from thymus tissue. The full-length protein has a reported molecular mass near 4963 Da, while material sold as TB-500 is often described as a fragment containing the actin-binding motif LKKTETQ. Because suppliers use the name inconsistently, published sources sometimes refer to the same label as a fragment, a synthetic copy, or a related analog. This naming ambiguity complicates direct comparison of reports across studies.
Laboratory work on thymosin beta-4 describes binding to monomeric actin and effects on cell migration, angiogenesis, and inflammatory signaling in cultured cells. Animal models have examined skin, corneal, and cardiac repair after injury, with outcomes reported mainly in preclinical literature. Most of that evidence concerns the parent protein rather than preparations labelled TB-500, so extrapolation from animal findings to a specific commercial product remains uncertain. Whether the two behave identically in living systems has not been established in controlled human studies.
Interest in the peptide grew during the 2000s and 2010s, when studies of tendon and ligament injuries in horses reported changes in lesion size after treatment. Those reports circulated widely outside the scientific literature and shaped much of the current online discussion. Subsequent reviews noted inconsistent study design, small groups, and a shortage of independent replication. Popular descriptions often blur the line between the fragment, the complete protein, and unrelated growth factors, which complicates comparisons across sources.
TB-500 is a synthetic peptide whose sequence corresponds to a short fragment near the N-terminus of thymosin beta-4, a small protein present in most mammalian cells. The fragment is commonly cited as containing the actin-binding region of the parent molecule, which is why it appears in laboratory work on cell migration and tissue repair. Suppliers distribute it as a lyophilised powder intended for research use. Its identity is defined by amino acid sequence and by the presence of an acetyl group on the N-terminal residue.
Full-length thymosin beta-4 consists of roughly forty-three amino acids and ranks among the more abundant small proteins in the cytoplasm. The fragment is much shorter, so it cannot reproduce every function attributed to the intact molecule. In cell culture, short actin-binding motifs can interfere with filament dynamics and cell movement, but such observations come from controlled experiments rather than from whole-animal work. Whether a truncated fragment produces the same effects as the parent protein remains an open question.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | Approximately 4963 Da for full-length thymosin beta-4 | Value applies to the parent protein; fragment products may differ |
| Appearance | White to off-white lyophilized powder | Typical form of supplied synthetic peptide |
| Solubility | Freely soluble in water | Polar peptide; dissolves readily in aqueous buffer |
| Storage of dry powder | −20 °C, desiccated, protected from light | Standard laboratory practice for peptides |
| Typical detection method | Liquid chromatography–tandem mass spectrometry | Used in purity testing and anti-doping analysis |
Controlled human trials of the short fragment are scarce. Much of what appears in review articles is extrapolated from animal models or from studies of the parent protein, and literature searches return a larger body of cardiac and ophthalmic work on thymosin beta-4 than on the abbreviated peptide. Regulatory treatment differs by jurisdiction, and in several countries the material is handled as a research chemical rather than an approved therapeutic. Statements about human benefit should be read as provisional.
Biological interest in this peptide centers on its relationship to actin dynamics. Thymosin beta-4 binds monomeric actin through an LKKTET motif, and a short sequence carrying that motif can compete with other actin-binding proteins in cell-free preparations. Investigators propose that such competition shifts the balance between filament assembly and disassembly, which in turn affects how readily a cell extends protrusions and migrates. Most of the supporting observations come from cultured cells and purified protein systems rather than from intact organisms.
Animal work has examined the peptide in models of cardiac injury, skin wounding, and corneal repair, with reported outcomes covering cell migration, inflammatory cell influx, and tissue remodeling. Several of those experiments used the full-length protein or longer fragments instead of the seven-residue sequence, which makes direct comparison between reports difficult. Results are generally described as tissue-dependent, and effect sizes vary considerably across laboratories. Independent replication is uneven, so the overall picture is incomplete rather than settled.
Thymosin beta-4 is a 43-residue actin-binding protein found in most mammalian cell types, where it participates in cytoskeletal regulation and cell migration. TB-500 represents only a short fragment of that protein and does not include the remaining residues. Whether the isolated fragment reproduces the full range of activities reported for the intact protein remains an open question. Researchers commonly treat the two as related but distinct entities when comparing results.
Published work involving this sequence spans actin-binding assays, cell-migration studies, wound-healing models, and cardiovascular or musculoskeletal experiments. Much of the biological rationale derives from in vitro systems and animal models, and the number of controlled human studies is small. Reported outcomes vary across preparations, doses, and routes, which complicates comparison between studies. Reviews generally describe the evidence base as preliminary rather than settled. Mechanistic explanations are often proposed by analogy to the parent protein rather than demonstrated directly.
TB-500 is a synthetic seven-amino-acid peptide with the sequence LKKTETQ, corresponding to residues 17 through 23 of the protein thymosin beta-4. The N-terminus is typically acetylated in the described form, giving a monoisotopic mass near 888.5 Da and an average mass of about 889 Da. The designation TB-500 is a catalogue label rather than a formal chemical name, and the same sequence appears in the literature under several alternative abbreviations. It is handled as a research reagent rather than a pharmaceutical product.
Lyophilized peptide powder is normally held desiccated at −20 °C, with −80 °C used for longer storage periods. Allowing a sealed vial to reach room temperature before opening is standard practice, because condensation forming on cold powder introduces moisture. Once dissolved, solutions are typically kept cold and shielded from light. Repeated freeze-thaw cycles are avoided because they encourage aggregation and gradual loss of material. These conventions are general to synthetic peptides rather than unique to any one sequence.
Purity and identity are separate measurements and are often confused. Reverse-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, reports the share of total peak area belonging to the target compound. Mass spectrometry by electrospray or matrix-assisted laser desorption then checks whether the observed mass matches the expected sequence. Neither measurement alone shows that a vial holds the intended peptide. Peptide content, meaning the fraction of vial mass that is genuine peptide rather than counter-ion, water or residual acid, is reported separately and is frequently lower than the stated purity figure.
The seven-residue chain carries several polar and charged side chains, so it dissolves readily in water and in aqueous buffers near neutral pH. No cysteine is present, so disulphide formation is not a concern and reducing agents are unnecessary. Dilute ammonium hydroxide or acetonitrile-water mixtures are sometimes used for stock solutions when initial dissolution is slow. Strongly alkaline conditions and prolonged contact with oxidising agents are avoided because they can modify lysine-containing stretches, and haze in solution usually signals incomplete dissolution or aggregated material.
Identity and purity are checked with reversed-phase high-performance liquid chromatography, which separates the target sequence from truncated or deletion analogues, and with mass spectrometry, which confirms the expected molecular mass. Amino acid analysis and peptide mapping give orthogonal confirmation but are used less often outside specialist laboratories. Counter-ion content varies: material purified on trifluoroacetic acid gradients retains trifluoroacetate, and ion exchange can convert the salt form. Residual water and solvent are measured by Karl Fischer titration or thermogravimetric analysis, and any purity figure should be read together with the method used to obtain it.
Lyophilised peptide powders are hygroscopic, and the fragment absorbs atmospheric moisture when a vial is opened at room temperature. Weighing and aliquoting are normally done quickly in a dry environment, and stock solutions are divided into single-use portions before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and can shift the measured content of a vial. These practices are general to synthetic peptides rather than unique to this sequence, but they matter more for short chains kept for long periods.
Robert Emmet Finnigan (May 27, 1927 – August 14, 2022) was an American pioneer in the development of gas chromatography–mass spectrometry equipment (GC/MS). Finnigan founded the Scientific Instruments Division of Electronic Associates, Inc., producing the first commercial quadrupole mass spectrometer in 1964. He then formed Finnigan Instruments Corporation to combine a computer system with a quadrupole mass spectrometer and gas chromatograph. Finnigan's GC/MS/computer systems are used to detect and identify trace organic compounds, making them important instruments for the monitoring and protection of the environment. They were adopted by the United States Environmental Protection Agency as a standard instrument for monitoring water quality and were fundamental to the work of the EPA.
Larry Friedman (Mulligan) performed in the musical Rasputin with Ted Neeley and John Hurt. Mion Hahm (Micki) is a realtor in Florida. Steve Einbender (Mike) is Senior Manager of Customer Analytics for The Home Depot, in Atlanta, Georgia. He still plays drums. Benjamin Sands (Manny) is a music teacher in the Washington, D.C. area. Sherry Wright (Maggie) pursued an acting and singing career while living in Alexandria, Virginia; she died in July 2009. Barry Michlin (Wilbur) had a number of minor roles throughout the 1970s and 1980s, and also made recurring appearances in several TV commercials including for Arm & Hammer Baking Soda with actress Beverly Sanders. He is a photographer based in Los Angeles.
In addition to management of the diabetes, it is recommended to have routine follow up with a primary care physician or endocrinologist in addition to a variety of specialists who assist in managing possible common complications such as foot ulcers, vision changes, and hearing loss.
Strained cyclooctenes and other activated alkenes react with tetrazines in an inverse electron-demand Diels-Alder reaction followed by a retro [4+2] cycloaddition (see figure). Three-membered and four-membered cycloalkenes, due to their high ring strain, also make ideal alkene substrates. Similar to other [4+2] cycloadditions, electron-donating substituents on the dienophile and electron-withdrawing substituents on the diene accelerate the inverse-demand Diels-Alder reaction. The diene, the tetrazine, by virtue of having the additional nitrogens, is a good diene for this reaction. The dienophile, the activated alkene, may often be attached to electron-donating alkyl groups on target molecules, thus making the dienophile more suitable for the reaction.
Whole lung lavage. this method involves repeatedly flushing the lungs with saline under intravenous anesthesia, together with mechanical ventilation, to remove the pathogenic factor Stopping further exposure to airborne silica, silica dust and other lung irritants, including tobacco smoking. Cough suppressants. Antibiotics for bacterial lung infection. Tuberculosis (TB) prophylaxis for those with positive tuberculin skin test or IGRA blood test. Prolonged anti-tuberculosis (multi-drug regimen) for those with active TB. Chest physiotherapy to help the bronchial drainage of mucus. Oxygen administration to treat hypoxemia, if present. Bronchodilators to facilitate breathing. Lung transplantation to replace the damaged lung tissue is the most effective treatment, but is associated with severe risks of its own from the lung transplant surgery as well as from consequences of long-term immunosuppression (e.g., opportunistic infections). For acute silicosis, bronchoalveolar lavage may alleviate symptoms, but does not decrease overall mortality. Preliminary work utilizing whole lung lavage for patients with artificial stone-associated silicosis has shown significant radiological improvement following the treatment.
Sources: en.wikipedia.org
Unlike most wealthy OECD countries, Australian law enables employers to not provide all rights of employment, particularly paid holidays and job security, if people are classed as "casual" employees, and in 2023 this meant around 22% of employees. To compensate for the absence of rights, modern awards typically grant a 25% "casual loading" additional pay, but potentially no holidays at all, putting Australia at odds with European Union practice There is also no legal mechanism to prevent employers rates of pay before the 25% loading is added. Under the Fair Work Act 2009 section 15A a casual employee exists if the relationship has an "absence of a firm advance commitment to continuing and indefinite work", replacing the previous notion that an employee simply accepts they do in a contract. This reversed the decision of the High Court in Workpac Pty Ltd v Rossato, that where a contract states someone is casual, even if the employer is providing them with ongoing work in regular and systematic shifts in reality, they are still casual employees and not entitled to paid holidays under FWA 2009 section 86. Casual workers are protected by unfair dismissal after 6 months, or 12 months for a small business, if they are deemed to work 'on a regular and systematic basis' and have a reasonable expectation of continued employment, but otherwise risk losing job security rights. Since 2021 casual workers must get an offer of a permanent contract offer after 12 months unless there are reasonable grounds to not make the offer.
=== Television === Australian actress Zoe Caldwell's performance in the 1982 Broadway adaptation of the Jeffers' script was recorded for broadcast on the PBS series Kennedy Center Tonight. Lars von Trier made a version for television in 1988, based on the script adaptation by Carl Theodor Dreyer. Theo van Gogh directed a miniseries version that aired 2005, the year following his murder. OedipusEnders, a documentary broadcast on BBC Radio 4 on 13 April 2010, discussed similarities between soap opera and Greek theatre. One interviewee revealed that the writers for the ITV police drama series The Bill had consciously and directly drawn on Medea in writing an episode for the series. Playwright Mike Bartlett was inspired to create a modern-day suburban Medea after adapting the Euripides play for a theatre production in 2012. Bartlett's 2015–2017 BBC1 miniseries Doctor Foster follows the structure of the Greek tragedy. A Korean remake of the series, The World of the Married, became the highest-rated cable drama in Korean history, with its final episode reaching a nationwide rating of 28.371%.
French Armed Forces Minister Sébastien Lecornu announced that France would donate dozens of armoured vehicles to the Lebanese military to help it carry out patrol missions. Since June 2024, the foreign ministries of Canada, Kuwait, Germany, the Netherlands and North Macedonia issued statements urging their citizens to leave Lebanon due to fears of an escalation of the conflict. The Canadian Armed Forces said that it was planning to evacuate its 20,000 citizens from Lebanon in the event of an escalation, although it would require support from its allies. On 8 November 2023, two men were arrested by Brazilian police in São Paulo following a warning from Mossad that Hezbollah was planning an attack against the country's Jewish community. Searches were also conducted in Brasília and Minas Gerais in connection with the alleged plot.
The American Journal of Respiratory Cell and Molecular Biology is a monthly peer-reviewed medical journal and an official publication of the American Thoracic Society. It covers research on the structure and function of the respiratory system under physiologic and pathophysiologic conditions. It was established in July 1989. The founding editors-in-chief were Jerome S. Brody, Robert M. Senior, and Mary C. Williams. John A. Mcdonald served as editor from 1993 to 1998. Kenneth B. Adler (North Carolina State University) served as editor from 2009 to 2016. Paul Schumacker (Northwestern University) served as editor from October 1, 2016, to October 21, 2023. Andrew Halayko (University of Manitoba) assumed the editorship on November 1, 2023. The journal is abstracted and indexed in BIOSIS Previews, Current Contents/Life Sciences, Current Contents/Critical Care Medicine, Embase, Index Medicus/MEDLINE/PubMed, Science Citation Index Expanded, and Scopus. According to the Journal Citation Reports, the journal has a 2024 impact factor of 5.3. Official website
Actinides are typical metals. All of them are soft and have a silvery color (but tarnish in air), relatively high density and plasticity. Some of them can be cut with a knife. Their electrical resistivity varies between 15 and 150 μΩ·cm. The hardness of thorium is similar to that of soft steel, so heated pure thorium can be rolled in sheets and pulled into wire. Thorium is nearly half as dense as uranium and plutonium, but is harder than either of them. All actinides are radioactive, paramagnetic, and, with the exception of actinium, have several crystalline phases: plutonium has seven, and uranium, neptunium and californium three. The crystal structures of protactinium, uranium, neptunium and plutonium do not have clear analogs among the lanthanides and are more similar to those of the 3d-transition metals. All actinides are pyrophoric, especially when finely divided, that is, they spontaneously ignite upon reaction with air at room temperature. The melting point of actinides does not have a clear dependence on the number of f-electrons. The unusually low melting point of neptunium and plutonium (~640 °C) is explained by hybridization of 5f and 6d orbitals and the formation of directional bonds in these metals.
Sources: en.wikipedia.org
== Discovery == Members of the Hsp70 family are very strongly upregulated by heat stress and toxic chemicals, particularly heavy metals such as arsenic, cadmium, copper, mercury, etc. Heat shock was originally discovered by Ferruccio Ritossa in the 1960s when a lab worker accidentally boosted the incubation temperature of Drosophila (fruit flies). When examining the chromosomes, Ritossa found a "puffing pattern" that indicated the elevated gene transcription of an unknown protein. This was later described as the "Heat Shock Response" and the proteins were termed the "Heat Shock Proteins" (Hsps).
The team is commonly known as Los Cafeteros ("The Coffee Growers"), after Colombia's coffee industry, and as La Tricolor, after the yellow, blue and red of the national flag. The Colombian state broadcaster's archive service has described the shirt as having become "a new national symbol", worn across regions and social classes on match days. Colombia's yellow shirt, blue shorts and red socks are a relatively recent settlement rather than an inherited palette. Early sides alternated white and blue, with white worn at the 1945 South American Championship and dark blue at the 1962 FIFA World Cup. From 1971 the team wore orange, known domestically as zapote. In 1985 the Colombian Football Federation commissioned the designer María Elvira Pardo to base a kit on the national flag; her design made red the first-choice shirt, worn through the 1990 FIFA World Cup, with yellow as the alternative. Yellow was promoted to first choice in the early 1990s. Subsequent departures have been tournament-specific: a red change kit at the 2014 FIFA World Cup referencing the 1990s alternates, and a white first-choice shirt at the Copa América Centenario echoing the 1945 side. Adidas has supplied the team since January 2011 under an agreement signed in November 2010, subsequently extended to 2030; earlier suppliers included Le Coq Sportif, Adidas, Puma, Kelme, Umbro, Reebok and Lotto.
== History == In May 2020, artesunate was approved for medical use in United States. Prior to this approval, intravenous (IV) artesunate was only available through the Expanded Access program of the U.S. Food and Drug Administration (FDA), which allowed the Centers for Disease Control and Prevention (CDC) to provide IV artesunate to people in the U.S. with severe malaria and to people with uncomplicated malaria who are unable to take oral medications under an investigational new drug (IND) protocol. There has been no FDA-approved drug for treatment of severe malaria in the United States since the marketing of quinidine was discontinued by the manufacturer in March 2019. The safety and efficacy of IV artesunate for the treatment of severe malaria was primarily evaluated in a randomized controlled trial in Asia (Trial 1) and a supportive published randomized controlled trial in Africa (Trial 2). Trial 1 was conducted at 10 sites in Myanmar, Bangladesh, India, and Indonesia. Trial 1 enrolled 1,461 participants who received either IV artesunate or the comparator drug quinine and included 202 pediatric participants younger than 15 years. Trial 2 included 5,425 randomized pediatric participants younger than 15 years of age with severe malaria who were treated with artesunate or quinine. In both trials, the number of participants treated with artesunate who died in the hospital was significantly lower than the number who died in the control group treated with quinine. Trial 2 was conducted during 2005–2010 in nine African countries.
(No prize had previously been awarded for that year.) They described him as "Linus Carl Pauling, who ever since 1946 has campaigned ceaselessly, not only against nuclear weapons tests, not only against the spread of these armaments, not only against their very use, but against all warfare as a means of solving international conflicts." Pauling himself acknowledged his wife Ava's deep involvement in peace work, and regretted that she was not awarded the Nobel Peace Prize with him.
Sources: en.wikipedia.org
Not necessarily. TB-500 is a commercial label that suppliers apply to synthetic peptides described as thymosin beta-4 or a fragment of it. Published research most often studies the full-length protein, so statements about one do not automatically transfer to the other.
No. No major regulatory authority lists an approved product under this name, and no pharmacopoeial monograph exists for it. Material sold under the label is therefore supplied outside approved pharmaceutical channels, which affects the quality documentation available.
It falls within a prohibited class covering peptide hormones and growth factors, based on presumed effects on tissue repair and blood vessel formation. Anti-doping laboratories have published mass spectrometry methods for detecting thymosin beta-4 related peptides in urine samples.
It is a synthetic peptide based on a short sequence near the start of thymosin beta-4. It is supplied as a research chemical rather than as a licensed pharmaceutical product.