If you have been reading about clinical endpoint 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.
Updated 2025-09-07. Numbers and descriptions here follow the published literature rather than marketing material.
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 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.
| Property | Value | Notes |
|---|---|---|
| Class | Synthetic peptide | 28 residues; not a small-molecule compound |
| Molecular mass | About 3,106 Da | Monoisotopic mass of the unmodified chain |
| N-terminal group | Acetylated serine | Present in both native and synthetic forms |
| Secondary structure | Disulfide-constrained loop | One bridge between two cysteine residues |
| Typical source | Solid-phase synthesis | Early isolates came from bovine thymus extracts |
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.
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.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
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.
== Neurobiology and behavior == In 1971, Ron Konopka and Seymour Benzer published "Clock mutants of Drosophila melanogaster", a paper describing the first mutations that affected an animal's behavior. Since then, Benzer and others have used behavioral screens to isolate genes involved in vision, olfaction, audition, learning/memory, courtship, pain, aggression, grooming, and other processes, such as longevity.
=== Table of standard amino acid alpha-helical propensities === Estimated differences in free energy change, Δ(ΔG), estimated in kcal/mol per residue in an α-helical configuration, relative to alanine arbitrarily set as zero. Higher numbers (more positive free energy changes) are less favoured. Significant deviations from these average numbers are possible, depending on the identities of the neighbouring residues.
==== Chromogenic microbiological media ==== Chromogenic microbiological media use colored enzymes to detect the presence of certain bacteria. In conventional bacteria culturing, bacteria are allowed to grow on a medium that supports many strains. Since it is hard to isolate bacteria, many cultures of different bacteria are able to form. To identify a particular bacteria culture, scientists must identify it using only its physical characteristics. Then further tests can be performed to confirm the presence of the bacteria, such as serology tests that find antibodies formed in organisms as a response to infection. In contrast, chromogenic microbiological media use particular color-producing enzymes that are targeted for metabolism by a certain strain of bacteria. Thus, if the given cultures are present, the media will become colored accordingly as the bacteria metabolize the color-producing enzyme. This greatly facilitates the identification of certain bacteria cultures and can eliminate need for further testing. To guard against misidentification of bacteria, the chromogenic plates typically incorporate additional enzymes that will be processed by other bacteria. Now, as the non-target bacteria interact with the additional enzymes, they will produce colors that distinguish them from the target bacteria.
Sources: en.wikipedia.org
The two substrates of this enzyme are (R)-3-hydroxybutyric acid and oxidised nicotinamide adenine dinucleotide (NAD+}. Its products are acetoacetic acid, reducad NADH, and a proton. This enzyme belongs to the family of oxidoreductases, to be specific, those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. This enzyme participates in the synthesis and degradation of ketone bodies and the metabolism of butyric acid.
The legislative election of 1957 was followed by several years of political stability that was accompanied by economic stagnation and curtailment of reforms and reformists. One of the last initiatives of the brief reform era was a nuclear weapons–free zone in Central Europe proposed in 1957 by Adam Rapacki, Poland's foreign minister. Culture in the Polish People's Republic, to varying degrees linked to the intelligentsia's opposition to the authoritarian system, developed to a sophisticated level under Gomułka and his successors. The creative process was often compromised by state censorship, but significant works were created in fields such as literature, theater, cinema and music, among others. Journalism of veiled understanding and varieties of native and Western popular culture were well represented. Uncensored information and works generated by émigré circles were conveyed through a variety of channels. The Paris-based Kultura magazine developed a conceptual framework for dealing with the issues of borders and the neighbors of a future free Poland, but for ordinary Poles Radio Free Europe was of foremost importance.
Jalapeños are a pod type of Capsicum annuum. The growing period is 70–80 days. When mature, the plant stands 70–90 cm (2 ft 4 in – 2 ft 11 in) tall. Typically, a plant produces 25 to 35 pods. During a growing period, a plant will be picked multiple times. As the growing season ends, the peppers turn red, as seen in sriracha sauce. Jalapeños thrive in a number of soil types and temperatures, though they prefer warmer climates, provided they have adequate water. The optimum temperature for seed germination is 29 °C (84 °F), with degradation of germination seen above 30 °C (86 °F) and little to no germination occurring at 40 °C (104 °F); at 29 °C (84 °F) the time to 50% germination rate depends on cultivar and seed lot but was tested as being between 4 and 5 days, which is shorter than cayenne. A pH of 4.5 to 7.0 is preferred for growing jalapeños, and well-drained soil is essential for healthy plants. Jalapeños need at least 6 to 8 hours of sunlight per day. Experiments show that unlike bell peppers at least 7.5 millimolar (mM) nitrogen is needed for optimal pod production, and 15 to 22 mM nitrogen produces the best result: the plant produces both more leaves and more pods, rather than just more leaves. Once picked, individual peppers may turn to red of their own accord. The peppers can be eaten green or red. Though usually grown as an annual they are perennial and if protected from frost can produce during multiple years, as with all Capsicum annuum.
Sources: en.wikipedia.org
== External links == Mediscuss on ESR Brigden ML (October 1999). "Clinical utility of the erythrocyte sedimentation rate". American Family Physician. 60 (5): 1443–50. PMID 10524488. ESR at Lab Tests Online
=== Pharmacokinetics === There have been several clinical studies to examine the pharmacokinetics of deramciclane, which can readily cross the blood–brain barrier. Overall, studies show that deramciclane follows linear pharmacokinetics in humans with oral daily doses ranging from 3–150 mg and twice daily doses ranging from 10–60 mg. Additionally, no differences have been found in adsorption, distribution, metabolism, or elimination when an oral dose is administered in tablet or capsule form. Deramciclane is rapidly absorbed from the gastrointestinal tract. Studies show that the drug can be detected in plasma as quickly as 20 minutes after dosing. Deramciclane demonstrates a Tmax of 2–4 hours and is unaffected by dosage. The Cmax at this time is approximately 140 ng/mL. A typical PTF (peak trough fluctuation) is 70-80% over four weeks of administration, and is unaffected by dose. The oral tablet of deramciclane yields a bioavailability of 36% on average, which is considered decent enough for oral administration and avoid the necessity of a more invasive route. The pharmacokinetics of deramciclane are also studied in rats, mice, rabbits, and dogs. Rat and rabbits show the fastest metabolism rates of the drug, and dogs are the only animals to show non-linear pharmacokinetics of deramciclane. Phase I metabolism in rat hepatocytes is similar enough to that in humans that the rat can be used as a predictive model for human metabolism of deramciclane. In rats, the Tmax is found to be 0.5 hours after a single 10 mg/kg dose and the half-life of deramciclane is about 3.5-5.5 hours.
A number of different methods have been described in the literature for preparing porous structures to be employed as tissue engineering scaffolds. Each of these techniques presents its own advantages, but none are free of drawbacks.
Sources: en.wikipedia.org
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.
The single bridge between two cysteine residues holds the chain in a folded loop that influences its shape and its behavior in solution. Loss of the bridge through reduction or oxidation shifts chromatographic retention and is tracked during stability work.
It is a defined 28-residue sequence derived from a larger precursor, whereas many other thymic preparations are mixtures of several polypeptides. Its acetylated amino terminus and single disulfide bridge distinguish it chemically from unrelated thymic extracts.
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.