This is a working overview of reverse-phase HPLC, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Recommended storage for the dry powder is a freezer near minus twenty degrees Celsius, kept desiccated and away from light. Once dissolved, the peptide is less stable and is usually held at two to eight degrees Celsius for short intervals or frozen for longer storage. Stability studies focus on the acetylated terminus and the disulfide linkage because those features define the intact molecule. Common degradation routes include cysteine oxidation, deamidation of asparagine or glutamine side chains, and slow formation of higher-molecular-weight species.
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.
| Property | Value | Notes |
|---|---|---|
| First described | 1977 | Reported as a component of thymosin fraction 5 |
| Sequence length | 28 amino acids | N-terminal residue is acetylated |
| Net charge at neutral pH | Negative | Reflects a high proportion of acidic residues |
| Principal studied uses | Chronic hepatitis B and vaccine adjuvant | Research uses outnumber approved indications |
| Regulatory status | Approved in a limited number of countries | Not approved in the United States or most of Europe |
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
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.
Light therapy is used to treat cases of neonatal jaundice. Bilirubin, a yellow pigment normally formed in the liver during the breakdown of old red blood cells, cannot always be effectively cleared by a neonate's liver causing neonatal jaundice. Accumulation of excess bilirubin can cause central nervous system damage, and so this buildup of bilirubin must be treated. Phototherapy uses the energy from light to isomerize the bilirubin and consequently transform it into compounds that the newborn can excrete via urine and stools. Bilirubin is most successful absorbing light in the blue region of the visible light spectrum, which falls between 460 and 490 nm. Therefore, light therapy technologies that utilize these blue wavelengths are the most successful at isomerizing bilirubin.
Brenner has been funded by agencies including the March of Dimes, the Burroughs Wellcome Fund, the Beckman Foundation, the Lung Cancer Research Foundation, the Bill & Melinda Gates Foundation, the Leukemia & Lymphoma Society, the National Science Foundation the National Institutes of Health and the Sigrid Juselius Foundation.
Epitope tags include ALFA-tag, V5-tag, Myc-tag, HA-tag, Spot-tag, T7-tag and NE-tag. These tags are particularly useful for western blotting, immunofluorescence and immunoprecipitation experiments, although they also find use in antibody purification. First described in 1984 by Munro and Pelham to detect and track proteins in COS cells, epitope tags were quickly adapted to track proteins in Xenopus oocytes; to detect and immunoaffinity purify proteins from yeast and E. coli; and to detect, pull down, and clone interaction partners of ligands in mammalian cells. At first, these tags were referred to as "peptide tag", "epitope insertion", "marker sequence", and "epitope addition", until "epitope tag" was coined and popularized. Fluorescence tags are used to give visual readout on a protein. Green fluorescent protein (GFP) and its variants are the most commonly used fluorescence tags. More advanced applications of GFP include using it as a folding reporter (fluorescent if folded, colorless if not). Protein tags may allow specific enzymatic modification (such as biotinylation by biotin ligase) or chemical modification (such as coupling to other proteins through SpyCatcher or reaction with FlAsH-EDT2 for fluorescence imaging). Often tags are combined, in order to connect proteins to multiple other components. However, with the addition of each tag comes the risk that the native function of the protein may be compromised by interactions with the tag. Therefore, after purification, tags are sometimes removed by specific proteolysis (e.g.
JINR did not propose a name after their first report claiming synthesis of element 105, which would have been the usual practice. This led LBL to believe that JINR did not have enough experimental data to back their claim. After collecting more data, JINR proposed the name bohrium (Bo) in honor of the Danish nuclear physicist Niels Bohr, a founder of the theories of atomic structure and quantum theory; they soon changed their proposal to nielsbohrium (Ns) to avoid confusion with boron. Another proposed name was dubnium. When LBL first announced their synthesis of element 105, they proposed that the new element be named hahnium (Ha) after the German chemist Otto Hahn, the "father of nuclear chemistry", thus creating an element naming controversy. In the early 1970s, both teams reported synthesis of the next element, element 106, but did not suggest names. JINR suggested establishing an international committee to clarify the discovery criteria. This proposal was accepted in 1974 and a neutral joint group formed. Neither team showed interest in resolving the conflict through a third party, so the leading scientists of LBL—Albert Ghiorso and Glenn Seaborg—traveled to Dubna in 1975 and met with the leading scientists of JINR—Georgy Flerov, Yuri Oganessian, and others—to try to resolve the conflict internally and render the neutral joint group unnecessary; after two hours of discussions, this failed. The joint neutral group never assembled to assess the claims, and the conflict remained unresolved.
Sources: en.wikipedia.org
Susan Weintraub is an American scientist. She is a professor at the University of Texas Health Science Center at San Antonio (UTHSCSA). She received a BS in chemistry from the University of Pennsylvania in 1967, MS in chemistry from Trinity University in 1970 and a PhD in biochemistry from UTHSCSA in 1979. She was the president of the American Society for Mass Spectrometry for the period of 2012-2014. In 2017 she was named a Fellow of the American Association for the Advancement of Science (AAAS), and Fellow of the American Society for Mass Spectrometry in 2025. She is an associate editor of the Journal of Proteome Research. Her research focuses on biomedical mass spectrometry where she used mass spectrometry in the early 1970s for quantitative analysis of brain neurochemicals. She has been director of the mass spectrometry core resource at UTHSCSA since 1979.
The terminal half-life of elagolix is typically about 4 to 6 hours. A study found that its half-life was 2.4 to 6.3 hours with a single dose and was 2.2 to 10.8 hours with continuous administration. The oral clearance of elagolix is 123 L/hour at 150 mg once per day and 144 L/hour at 200 mg twice per day. The major pathway of elimination of elagolix is hepatic metabolism. Elagolix is taken up from the circulation into the liver by the hepatic OATP1B1 carrier. In people with two reduced function alleles of the gene that encodes OATP1B1 (SLCO1B1 521T>C; SLCO1B1 521 C/C genotype), plasma levels of elagolix have been found to be increased by 78% relative to in people with normal OATP1B1 function (SLCO1B1 521T/T genotype). The frequency of this reduced function OATP1B1 genotype is generally less than 5% in most racial and ethnic groups. Elagolix is excreted less than 3% in urine and 90% in feces. Exposure to elagolix is not affected by renal impairment or mild hepatic impairment, but is increased by approximately 3-fold in women with moderate hepatic impairment and by approximately 7-fold in women with severe hepatic impairment. There were no differences in the pharmacokinetics of elagolix between individuals of different racial and ethnic groups. Similarly, the pharmacokinetics of elagolix were unaffected by body weight and body mass index. Peak and area-under-the-curve levels of elagolix have been shown to be altered by CYP3A4 inhibitors like ketoconazole and CYP3A4 inducers like rifampin.
==== Platelet-rich plasma ==== The effectiveness of injections of platelet-rich plasma (PRP) is unclear; there are suggestions that such injections improve function but not pain, and are associated with increased risk. A 2014 Cochrane review of studies involving PRP found the evidence to be insufficient.
== Description == Datura species are herbaceous, leafy annuals and short-lived perennials, which can reach up to 2 m (6 ft 7 in) in height. The leaves are alternate, 10–20 cm (3.9–7.9 in) long, and 5–18 cm (2.0–7.1 in) broad, with a lobed or toothed margin. The flowers are erect or spreading (not pendulous like those of Brugmansia), trumpet-shaped, 5–20 cm (2.0–7.9 in) long, and 4–12 cm (1.6–4.7 in) broad at the mouth; colours vary from white to yellow and pale purple. The fruit is a spiny capsule, 4–10 cm (1.6–3.9 in) long and 2–6 cm (0.8–2 in) broad, splitting open when ripe to release the numerous seeds. The seeds disperse freely over pastures, fields and even wasteland locations. Datura belongs to the classic "witches' weeds", along with deadly nightshade, henbane and mandrake. All parts of the plants are toxic, and the genus has a long history of use for causing delirious states and death. It was well known as an essential ingredient of magical ointments, potions and witches' brews, most notably Datura stramonium. In India, D. metel has long been regarded as a poison and aphrodisiac, having been used in Ayurveda as a medicine since ancient times. It features in rituals and prayers to Shiva and also in Ganesh Chaturthi, a festival devoted to the deity Ganesha. The larvae of some Lepidoptera (butterfly and moth) species, including Hypercompe indecisa, eat some Datura species. It has been observed that while insects may prefer to feed on Datura leaves, other animals such as cows will generally avoid consuming them.
== Normal levels == Progesterone is used as part of hormone replacement therapy in people who have low progesterone levels, and for other reasons. For purposes of comparison with normal physiological circumstances, luteal phase levels of progesterone are 4 to 30 ng/mL, while follicular phase levels of progesterone are 0.02 to 0.9 ng/mL, menopausal levels are 0.03 to 0.3 ng/mL, and levels of progesterone in men are 0.12 to 0.3 ng/mL. During pregnancy, levels of progesterone in the first 4 to 8 weeks are 25 to 75 ng/mL, and levels are typically around 140 to 200 ng/mL at term. Production of progesterone in the body in late pregnancy is approximately 250 mg per day, 90% of which reaches the maternal circulation.
Sources: en.wikipedia.org
== Beneficial and conditional mutations == Although mutations that cause changes in protein sequences can be harmful to an organism, on occasions the effect may be positive in a given environment. In this case, the mutation may enable the mutant organism to withstand particular environmental stresses better than wild-type organisms, or reproduce more quickly. In these cases a mutation will tend to become more common in a population through natural selection. That said, the same mutation can be beneficial in one condition and disadvantageous in another condition. Examples include the following: HIV resistance: a specific 32 base pair deletion in human CCR5 (CCR5-Δ32) confers HIV resistance to homozygotes and delays AIDS onset in heterozygotes. One possible explanation of the etiology of the relatively high frequency of CCR5-Δ32 in the European population is that it conferred resistance to the bubonic plague in mid-14th century Europe. People with this mutation were more likely to survive infection; thus its frequency in the population increased. This theory could explain why this mutation is not found in Southern Africa, which remained untouched by bubonic plague. A newer theory suggests that the selective pressure on the CCR5 Delta 32 mutation was caused by smallpox instead of the bubonic plague. Malaria resistance: An example of a harmful mutation is sickle-cell disease, a blood disorder in which the body produces an abnormal type of the oxygen-carrying substance haemoglobin in the red blood cells.
Countries requiring passports valid for at least 4 months on arrival include Micronesia and Zambia. Countries requiring passports with a validity of at least 3 months beyond the date of intended departure include Azerbaijan, Bosnia and Herzegovina, Honduras, Montenegro, Nauru, Moldova and New Zealand. Similarly, the EEA countries of Iceland, Liechtenstein, Norway, all European Union countries (except Ireland) together with Switzerland also require 3 months validity beyond the date of the bearer's intended departure unless the bearer is an EEA or Swiss national. Countries requiring passports valid for at least 3 months on arrival include Albania, North Macedonia, Panama, and Senegal. Bermuda requires passports to be valid for at least 45 days upon entry. Countries that require a passport validity of at least one month beyond the date of intended departure include Eritrea, Hong Kong, Lebanon, Macau, the Maldives and South Africa.
Properdin is a protein that in humans is encoded by the CFP (complement factor properdin) gene. Properdin and factor H are regulatory proteins in the alternative complement pathway. Properdin is an up-regulator, stabilizing the C3bBb complex, and factor H is the down-regulator, promoting proteolytic degradation of C3b. Factor H is primarily produced in the liver, whereas properdin is sourced in neutrophils, monocytes, T cells and bone marrow progenitor cell line. Properdin is plasma glycoprotein that activates the complement system of the innate immune system. It is found in plasma and primarily produced by leukocytes. This protein binds to bacterial cell walls and dying human cells to stabilize the C3 and C5-convertase enzyme complexes to form an attack complex that leads to the lysis of the cell. The complement system is made of plasma and membrane-bound proteins that go through the blood to get rid of pathogens and damaged cells. Activation of the complement system occurs via three pathways, the classical, lectin, and alternative pathways. Activation of the alternative pathway occurs in bacteria, yeast, and parasites and is stimulated by antibody-antigen complexes made of IgG or IgA. Properdin and factor H are important regulatory proteins of the alternative pathway, which is initiated by a conformational change in C3 cleaved at a single site by the serine protease C3 convertase.
is time (unit s). Further simulations and analysis of this equation show that the square root dependence on the time is originated from the decrease of the concentrations near the surface under ideal adsorption conditions. Also, this equation only works for the beginning of the adsorption when a well-behaved concentration gradient forms near the surface. Correction on the reduction of the adsorption area and slowing down of the concentration gradient evolution have to be considered over a longer time. Under real experimental conditions, the flow and the small adsorption area always make the adsorption rate faster than what this equation predicted, and the energy barrier will either accelerate this rate by surface attraction or slow it down by surface repulsion. Thus, the prediction from this equation is often a few to several orders of magnitude away from the experimental results. Under special cases, such as a very small adsorption area on a large surface, and under chemical equilibrium when there is no concentration gradience near the surface, this equation becomes useful to predict the adsorption rate with debatable special care to determine a specific value of
Two people were killed in a Russian airstrike in Zolochiv, Kharkiv Oblast. Two people were also killed in a Russian missile strike in Hirnyk, Donetsk Oblast. A missile strike on Odesa injured 14 people. In Russia, the governor of Ryazan Oblast claimed that an oil refinery was set on fire by a drone. The governor of Voronezh Oblast claimed that a drone was shot down over Voronezh city, while energy infrastructure was also damaged by drones in Kursk and Oryol Oblasts. Ukrainian special forces claimed to have disabled two Russian Buk missile systems in Sumy Oblast using attack drones. Several Russian personnel were claimed killed and equipment destroyed during a Ukrainian strike on Rohove, Luhansk Oblast. It is believed three missiles, either ATACMS or Tochka-U, were used with cluster munitions. The head of the SBU's cybersecurity unit, Illia Vitiuk, was dismissed by Zelenskyy following investigations into suspicious financial activities by the former's wife while he was in office and attempts by SBU personnel to harass journalists. The United States Department of State alleged the use of chloropicrin by Russian forces in Ukraine and imposed fresh sanctions against Russian individuals and entities as a response. Russia placed several captured and destroyed Western armored vehicles on display at Moscow, including an M1A1 Abrams, M2A2 Bradley, Leopard 2A6 and several types of lighter NATO-origin armored vehicles.
Sources: en.wikipedia.org
Trials differ in patient population, dose schedule, background treatment, and the endpoints used to judge success. Many are small and single-center, so random variation can dominate the reported effects.
Authorization is limited to a small number of countries and covers specific indications such as chronic hepatitis B and vaccine adjuvant use. Availability and labelling differ by jurisdiction.
Most reviews describe it as an immunomodulatory agent with an uncertain clinical effect. They generally call for larger, better-controlled trials before firm conclusions are drawn.
Reconstituted solutions are typically kept refrigerated at two to eight degrees Celsius when used within a short window, or frozen in aliquots for longer periods. Repeated freeze-thaw cycles are avoided because they can reduce recovery of intact peptide.