This is a working overview of mass spectrometry, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-29. 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.
Once in solution, short peptides are generally less stable than the dry powder, and repeated freeze-thaw cycles are a common cause of loss. Laboratory guidance usually calls for aliquoting on first dissolution and storing aliquots at -20 °C or below, away from light. Adsorption to plastic and glass surfaces can lower measured concentration, particularly at low concentrations, so container material and buffer choice can affect results. Visible cloudiness, colour change or unexpected precipitate is a signal to re-check the material.
Purity is normally assessed by reversed-phase HPLC, with the main peak reported as a percentage of total peak area, while identity is confirmed by mass spectrometry. Electrospray and MALDI-TOF instruments are both used, and the observed mass is compared with the value calculated from the stated sequence. Ion-exchange or size-exclusion methods appear where aggregation or charge variants are of interest. Water content, counter-ion content and residual trifluoroacetate from purification are separate variables that can shift the measured mass and should be weighed when reading a certificate of analysis.
| 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 |
Identity and purity are normally assessed with reversed-phase high-performance liquid chromatography, paired with mass spectrometry to confirm molecular mass. A certificate of analysis reports a purity percentage, usually derived from chromatographic peak area, but that figure does not by itself prove a correct sequence or the absence of counterions. Independent verification may include amino acid analysis or peptide mapping. Batch-to-batch variation is a documented concern in the research chemical market, and the gap between a quoted purity value and actual peptide content can be substantial when the material is a salt or retains residual water.
Lyophilized peptide arrives as a dry cake that should stay sealed until use. Reconstitution is generally performed with sterile water or a buffered solution, and the resulting liquid should be handled gently to limit mechanical stress. Repeated freeze-thaw cycles are widely described as harmful to short peptides, so dividing a reconstituted batch into single-use portions is a common practice. Laboratories also record the solvent, concentration, and date of preparation on the vial label to keep later measurements traceable.
Detection in biological samples relies on mass spectrometry, typically liquid chromatography coupled to tandem mass spectrometry after peptide extraction and enrichment. Intact peptides can also be confirmed by high-resolution mass measurement together with fragmentation data. Detection windows in urine are short because the peptide is degraded by proteases and cleared quickly, and concentrations are low. Many jurisdictions treat the compound as a prohibited substance in sport, grouped with peptide hormones and related factors, while it is not an approved therapeutic product. Identity and purity statements therefore rest on certificates of analysis, ideally issued by an independent laboratory.
Material is normally supplied as a lyophilised powder in a sealed vial. The powder is hygroscopic, so exposure to humid air leads to water uptake, caking and gradual loss of the fluffy texture that indicates a good freeze-dry. Vials are best kept sealed with desiccant, protected from light and stored cold. Letting a cold vial warm to room temperature before opening reduces condensation on the contents. Purity is normally reported from a chromatographic run, and that figure applies to the batch as tested rather than to the vial after repeated opening.
Lichen systematics is the study of how lichens are classified and related to each other, combining the naming of lichen taxa, the reconstruction of their evolutionary history, and the organization of this diversity into a coherent framework. In contrast to an individual fungus or plant, a lichen is not a single organism but a miniature ecosystem—a symbiotic partnership between a fungus (the mycobiont) and a photosynthetic partner (the photobiont, typically an alga or cyanobacterium). Because a lichen has no independent evolutionary lineage apart from its partners, classification is based chiefly on the fungus's family tree. Lichen systematics underpins broader biodiversity research and conservation. Species are the fundamental units in ecology and biogeography, so a stable taxonomy is essential for tracking environmental changes and protecting vulnerable species. Inaccurate taxonomy can mislead science and policy. One audit of conservation data found that database records for a rare lichen had been misidentified or filed under obsolete names, distorting assessments of its geographic range. Modern lichen systematics therefore emphasizes rigorous definition of species boundaries and thorough documentation as the foundation for studying lichens' ecology and evolution. At its core, lichen systematics rests on four interlinked pillars.
ABS-201 is an AI-designed monoclonal antibody against the prolactin receptor (PRLR) currently in Phase 1/2a clinical trial for the treatment of androgenic alopecia (pattern hair loss) and endometriosis. It is taken by subcutaneous injection. ABS-201 is a possible first-in-class drug with a novel mechanism of action in the potential treatment of hair loss. ABS-201 is under development by Absci. It is believed that ABS-201 works by activating dormant hair follicles and causing them to move from the telogen phase to the anagen phase. In human ex vivo scalp model studies, ABS-201 stimulated hair regrowth, prolonged anagen phase, blocked catagen phase, inhibited telogen effluvium, and blocked hair from losing color. ABS-201 has been found to produce robust hair regrowth as compared with minoxidil in mice and balding macaques. The clinical trial for ABS-201 is being overseen by prominent hair loss researcher Rodney Sinclair, one of the principal investigators in minoxidil clinical trials. The chemical structure of the drug does not yet appear to have been disclosed.
CRISPR gene editing is a revolutionary technology that allows for precise, targeted modifications to the DNA of living organisms. Developed from a natural defense mechanism found in bacteria, CRISPR-Cas9 is the most commonly used system. Gene editing with CRISPR-Cas9 involves a Cas9 nuclease and an engineered guide RNA, which come together to allow for the precise "cutting" of one or both strands of DNA at specific locations within the genome. It makes use of the cell's natural DNA repair systems, including non-homologous end joining, homology-directed repair, or mismatch repair, to modify, insert, or delete genetic material at these specific cut sites. This technology has transformed fields such as genetics, medicine, and agriculture, offering potential treatments for genetic disorders, advancements in crop engineering, and research into the fundamental workings of life. However, its ethical implications and potential unintended consequences have sparked significant debate.
Auto-oxidation reaction is also observed with common ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran, and 1,4-dioxane. An illustrative product is diethyl ether peroxide. Such compounds can result in a serious explosion when distilled. To minimize this problem, commercial samples of THF are often inhibited with butylated hydroxytoluene (BHT). Distillation of THF to dryness is avoided because the explosive peroxides concentrate in the residue. Although ether hydroperoxide often form adventitiously (i.e. autoxidation), they can be prepared in high yield by the acid-catalyzed addition of hydrogen peroxide to vinyl ethers: C2H5OCH=CH2 + H2O2 → C2H5OCH(OOH)CH3 Many industrial peroxides are produced using hydrogen peroxide. Reactions with aldehydes and ketones yield a series of compounds depending on conditions. Specific reactions include addition of hydrogen peroxide across the C=O double bond: R2C=O + H2O2 → R2C(OH)OOH In some cases, these hydroperoxides convert to give cyclic diperoxides:
Sources: en.wikipedia.org
80. Coll Antropol. 2005 Jun;29(1):321-5. Gastric pentadecapeptide BPC 157 promotes corneal epithelial defects healing in rats. Lazić R(1), Gabrić N, Dekaris I, Bosnar D, Boban-Blagaić A, Sikirić P. Author information: (1)Eye Clinic, Svjetlost, Zagreb, Croatia. ratimir.lazic@zg.htnet.hr We evaluated the role of human gastric pentadecapeptide BPC 157 in corneal epithelial defects healing in rats. 48 rats, in 4 groups (N=12). Total debridement of corneal epithelium preformed unilaterally and lesions stained and photographed. Animals medicated as follows: distilled water (control group) or BPC 157 2 pg/ml, 2 ng/ml, 2 microg/ml, 2 drops/rat eye started immediately after injury induction, every 8 hours up to 40 hours (i.e., at 0, 8, 16, 24, 32, 40 h). Lesions were photographed before application or sacrifice (at 48 h). Defect area was analyzed using a special program. Through 48 hour period a steady recovery is noted in controls. Recovery was markedly accelerated in eyes on microg- or ng-topical regimen of BPC 157 (p < 0.05). Of note, unlike control lesion present also after 48 h, these lesions disappeared already following 40 h (microg) or 48 h (ng) post-injury. BPC 157 was shown to be effective in promoting corneal defects healing in rats. Results were dose dependent.
=== Wound healing === As a component of skin tissue, collagen is a base material for medical products to support wound healing. When collagen is made available to the wound bed, closure can occur, avoiding wound deterioration and severe surgical procedures, such as amputation. Collagen is used as a natural wound dressing because it has properties that artificial wound dressings do not have. It resists bacteria, which is vitally important in wound dressing. As a burn dressing, collagen aids healing by enabling granulation tissue to grow over the burn. Throughout the four phases of wound healing, collagen performs the following functions:
Further separation was carried out by ion exchange, yielding a certain isotope of curium. The separation of curium and americium was so painstaking that those elements were initially called by the Berkeley group as pandemonium (from Greek for all demons or hell) and delirium (from Latin for madness). Initial experiments yielded four americium isotopes: 241Am, 242Am, 239Am and 238Am. Americium-241 was directly obtained from plutonium upon absorption of two neutrons. It decays by emission of a α-particle to 237Np; the half-life of this decay was first determined as 510±20 years but then corrected to 432.2 years.
=== Sales === US sales of the drug were of $2.2 billion in 2006. Sales in 2Q 2007 down 22% compared to 2006. 4Q 2007 sales down to $252 million. Though sales have gone down since 2007 due to safety concerns, Avandia sales for 2009 totalled $1.2 billion worldwide.
== Natural occurrence == Phenethylamine is produced by a wide range of species throughout the plant and animal kingdoms, including humans; it is also produced by certain fungi and bacteria (genera: Lactobacillus, Clostridium, Pseudomonas and the family Enterobacteriaceae) and acts as a potent antimicrobial against certain pathogenic strains of Escherichia coli (e.g., the O157:H7 strain) at sufficient concentrations.
Sources: pubmed.ncbi.nlm.nih.gov
== Products == The company's research and development activities are focused on drugs for the treatment of severe, resistant bacterial infections and life-threatening, invasive fungal diseases. Basilea's products are aimed at diseases that have so far been insufficiently treatable. The company markets the following products exclusively through licence and distribution partners: Ceftobiprole (trade name Zevtera/Mabelio) is a broad-spectrum antibiotic administered intravenously for community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP) in adults. It has an active effect against the bacterium Staphylococcus aureus (MRSA), including methicillin-resistant strains, and against penicillin-resistant Streptococcus pneumoniae (PRSP) bacteria, as well as against gram-negative pathogens such as Enterobacteriaceae. Isavuconazole (trade name Cresemba) is an intravenous and oral antifungal agent for the treatment of patients with invasive aspergillosis and invasive mucormycosis. While Astellas is responsible for the commercialisation of Cresemba in the USA, the pharmaceutical group Pfizer covers the commercialisation in most of Europe and also distributes Cresemba in China and the Asia–Pacific (APAC) area. Basilea's distribution partner in the MENA region is Hikma Pharmaceuticals LLC; Knight Therapeutics Inc. commercialises the antifungal Cresemba in South America.
Ceftaroline has low water solubility but this problem was overcome by attaching a N-phosphonoamino group to the molecule making the intravenous prodrug ceftaroline fosamil. The prodrug is dephosphorylated in plasma to form active ceftaroline.
Exposure to PFAS, some of which are carcinogens or endocrine disruptors, has been linked to diseases and health conditions including cancers, ulcerative colitis, thyroid disease, suboptimal antibody response or decreased immunity, decreased fertility, hypertensive disorders in pregnancy, fetal and child developmental issues, obesity, and high cholesterol. Due to the health and environmental concerns associated with many PFAS, PFOS and PFOA were listed in the Stockholm Convention on Persistent Organic Pollutants in 2009 and 2019, respectively. However, it is challenging to assess the potential risks of all PFAS due to the large data-gaps in toxicity and physicochemical properties. With thousands of compounds used in various application, only a few have undergone comprehensive biological testing. In some jurisdictions, such as the European Union, further reductions and phase-outs of PFAS are planned. Several companies are voluntarily ending or planning to end the sale of PFAS and PFAS-containing products due to health and litigation concerns. However, major producers and users such as the United States, Israel, and Malaysia have not ratified the agreement and the chemical industry has lobbied governments to reduce regulations.
=== 24 May === Ukrainian authorities ordered the mandatory evacuation of 123 children from 36 settlements in Kharkiv Oblast due to Russian attacks. The United States sent another military aid package for Ukraine, valued at $275 million. It included HIMARS, munitions, 155 mm and 105 mm high-demand artillery rounds, Javelin and AT4 antitank systems, antitank mines, tactical vehicles, small arms and ammunition. The Ukrainian Air Force announced that it had begun using air dropped Small Diameter Bombs, which had "proved resilient to jamming" and had a "nearly 90 percent" accuracy rate, since November 2023.
==== Using detrital zircon age abundance ==== In a global scale, detrital zircon age abundance can be used as a tool to infer significant tectonic events in the past. In Earth's history, the abundance of magmatic age peaks during periods of supercontinent assembly. This is because supercontinent provides a major crustal envelop selectively preserve the felsic magmatic rocks, resulting from partial melts. Thus, many detrital zircons originate from these igneous provence, resulting similar age peak records. For instance, the peak at about 0.6–0.7 Ga and 2.7 Ga (Figure 6) may correlate the break-up of Rodinia and supercontinent Kenorland respectively.
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.
Sealed, desiccated and protected from light, at -20 °C or lower for long-term storage. Short-term storage at refrigerator temperature is common in working laboratories.