Selank raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-01-07. Anything still debated is marked as such rather than presented as settled.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
=== Aglyphous snakes === Experiments made with the secretion of the parotid gland of Rhabdophis and Zamenis have shown that even aglyphous snakes are not entirely devoid of venom, and point to the conclusion that the physiological difference between so-called harmless and venomous snakes is only one of degree, just as various steps exist in the transformation of an ordinary parotid gland into a venom gland or of a solid tooth into a tubular or grooved fang.
Prodynorphin, also known as proenkephalin B, is an opioid polypeptide hormone involved with chemical signal transduction and cell communication. The gene for prodynorphin is expressed in the endometrium and the striatum, and its gene map locus is 20pter-p12. Prodynorphin is a basic building-block of dynorphins, the chemical messengers in the brain that appear most heavily involved in the anticipation and experience of pain, stress responses, as well appetite and temperature regulation, as well as neoendorphins. The gene is thought to influence perception, as well as susceptibility to drug dependence, and is expressed more readily in human beings than in other primates.
=== Excess facial hair in women === The topical cream is indicated for treatment of facial hirsutism in women. It is the only topical prescription treatment that slows the growth of facial hair. In clinical studies with Vaniqa, 81% of women showed clinical improvement after twelve months of treatment. Positive results were seen after eight weeks. However, discontinuation of the cream caused regrowth of hair back to baseline levels within 8 weeks. Vaniqa treatment significantly reduces the psychological burden of facial hirsutism.
Bush, after receiving a phone call from Boris Yeltsin, delivers a Christmas Day speech acknowledging the end of the Cold War. December 26: The Council of the Republics of the Supreme Soviet of the USSR dissolves the Soviet Union. The United States became the world's only superpower.
=== Mechanotransductive === Additionally, YAP is regulated by mechanical cues such as extracellular matrix (ECM) rigidity, strain, shear stress, or adhesive area, processes that are reliant on cytoskeletal integrity. These mechanically induced localization phenomena are thought to be the result of nuclear flattening induced pore size change, mechanosensitive nuclear membrane ion channels, mechanical protein stability, or a variety of other factors. These mechanical factors have also been linked to certain cancer cells via nuclear softening and higher ECM stiffnesses. Under this framework, the nuclear softening phenotype of cancer cells would promote nuclear flattening in response to a force, causing YAP localization, which could explain its over-expression and promoted proliferation in oncogenic cells. Additionally, the higher ECM stiffness phenotype commonly seen in tumors due to enhanced integrin signaling could flatten the cell and nucleus, once again causing higher YAP nuclear localization. Likewise, the opposite effect of nuclear stiffening as a result of a variety of stimuli such as an over-expression of lamin A, has been shown to decrease nuclear YAP localization.
Sources: en.wikipedia.org
=== Precursor of Others === Arginine is also a precursor for urea, ornithine, and agmatine; is necessary for the synthesis of creatine; and can also be used for the synthesis of polyamines (mainly through ornithine and to a lesser degree through agmatine, citrulline, and glutamate). The presence of asymmetric dimethylarginine (ADMA), a close relative, inhibits the nitric oxide reaction; therefore, ADMA is considered a marker for vascular disease, just as L-arginine is considered a sign of a healthy endothelium. In mammals, arginine can be converted into proline via glutamate-5-semialdehyde and pyrroline-5-carboxylic acid. The conversion of arginine into other amino acids also occurs in bacteria; for example, species of the genus Bacillus can convert arginine into proline or glutamic acid via ornithine. The Solanum alkaloids (from the plant family Solanaceae) and Veratrum alkaloids (genus Veratrum) are synthesized from cholesterol via biosynthesis. Nitrogen is introduced from arginine through transamination. Vargulin is a luciferine formed by shellfish from arginine, tryptophan, and isoleucine, and is used to produce bioluminescence in the form of blue light. During bioluminescence, the reaction of a luciferin with a luciferase generates an energetically excited molecule that emits light. Vargulin is found in the genera Vargula and Cypridina, as well as in certain fish species that consume shellfish and acquire the compound through their diet.
Alcohol dehydrogenases (ADH) (EC 1.1.1.1) are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to NADH. In humans and many other animals, they serve to break down alcohols that are otherwise toxic, and they also participate in the generation of useful aldehyde, ketone, or alcohol groups during the biosynthesis of various metabolites. In yeast, plants, and many bacteria, some alcohol dehydrogenases catalyze the opposite reaction as part of fermentation to ensure a constant supply of NAD+.
=== Proteomics === Screens for biologically relevant protein-protein interactions have been performed using Tandem Affinity Purification (TAP) with the SBP-Tag and Protein A, for interaction proteomics and transcription factor complexes with the SBP-Tag and Protein G, for proteins that interact with the Dengue Virus protein DENV-2 NS4A with the SBP-Tag and the Calmodulin Tag. and for proteins that interact with protein phosphatase 2A (PP2A) with the SBP-Tag and the hemagglutinin (HA)-tag.
The pelycosaurs are synapsids (more closely related to mammals) while the ctenosauriscids are archosaurs (closely related to crocodilians, pterosaurs and dinosaurs). Also, the spinosaurids had sail-like fins on their backs, when they were not closely related to either. Also, Acrocanthosaurus and Ouranosaurus, which are not closely related to either pelycosaurs, ctenosauriscids or spinosaurids, also had similar, but thicker, spines on their vertebrae. Noasaurus, Baryonyx, and Megaraptor, all unrelated, all had an enlarged hand claw that were originally thought to be placed on the foot, as in dromaeosaurs. A similarly modified claw (or in this case, finger) is on the hand of Iguanodon. The ornithopods had feet and beaks that resembled that of birds, but are only distantly related. Three groups of dinosaurs, the Tyrannosauridae, Ornithomimosauria, and the Troodontidae, all evolved an arctometatarsus, independently. Some placodonts (like Cyamodus, Psephoderma, Henodus and especially Placochelys) bear striking resemblance to sea turtles (and turtles in general) in terms of size, shell, beak, mostly toothless jaws, paddle-shaped limbs and possibly other adaptations for aquatic lifestyle.
The collection grew slowly and suffered another major fire in 1851, which destroyed two-thirds of Jefferson's original books. The Library of Congress faced space shortages, understaffing, and lack of funding, until the American Civil War increased the importance of legislative research to meet the demands of a growing federal government. In 1870, the library gained the right to receive two copies of every copyrightable work printed in the United States; it also built its collections through acquisitions and donations. Between 1890 and 1897, a new library building, now the Thomas Jefferson Building, was constructed. Two additional buildings, the John Adams Building (opened in 1939) and the James Madison Memorial Building (opened in 1980), were later added. The LC's Congressional Research Service provides objective non-partisan research to Congress to assist it in passing legislation. The library is open to the public for research, although only members of Congress, their staff, and library employees may borrow materials for use outside the library.
Sources: en.wikipedia.org
The disease progresses by forming granulation tissue at the edges of the synovial lining, pannus with extensive angiogenesis and enzymes causing tissue damage. The fibroblast-like synoviocytes have a prominent role in these pathogenic processes. The synovium thickens, cartilage and underlying bone disintegrate, and the joint deteriorates, with raised calprotectin levels serving as a biomarker of these events. Cytokines and chemokines attract and accumulate immune cells, i.e., activated T- and B cells, monocytes, and macrophages from activated fibroblast-like synoviocytes, in the joint space. By signalling through RANKL and RANK, they eventually trigger osteoclast production, which degrades bone tissue. The fibroblast-like synoviocytes that are present in the synovium during rheumatoid arthritis display altered phenotype compared to the cells present in normal tissues. The aggressive phenotype of fibroblast-like synoviocytes in rheumatoid arthritis and the effect these cells have on the microenvironment of the joint can be summarized into hallmarks that distinguish them from healthy fibroblast-like synoviocytes. These hallmark features of fibroblast-like synoviocytes in rheumatoid arthritis are divided into seven cell-intrinsic hallmarks and four cell-extrinsic hallmarks. The cell-intrinsic hallmarks are: reduced apoptosis, impaired contact inhibition, increased migratory invasive potential, changed epigenetic landscape, temporal and spatial heterogeneity, genomic instability and mutations, and reprogrammed cellular metabolism.
Neutrophils are the most abundant white blood cells in the human body (approximately 1011 are produced daily); they account for approximately 50–70% of all white blood cells (leukocytes). The stated normal range for human blood counts varies between laboratories, but a neutrophil count of 2.5–7.5 × 109/L is a standard normal range. People of African and Middle Eastern descent may have lower counts, which are still normal. A report may divide neutrophils into segmented neutrophils and bands. When circulating in the bloodstream and inactivated, neutrophils are spherical. Once activated, they change shape and become more amorphous or amoeba-like and can extend pseudopods as they hunt for antigens.
== Fiber types == Broadly there are two types of muscle fiber: Type I, which is slow, and Type II which are fast. Type II has two divisions of type IIA (oxidative), and type IIX (glycolytic), giving three main fiber types. These fibers have relatively distinct metabolic, contractile, and motor unit properties. The table below differentiates these types of properties. These types of properties—while they are partly dependent on the properties of individual fibers—tend to be relevant and measured at the level of the motor unit, rather than at the individual fiber.
Ghiorso and co-workers analyzed filter papers which had been flown through the explosion cloud on airplanes (the same sampling technique that had been used to discover 244Pu). Larger amounts of radioactive material were later isolated from coral debris of the atoll, and these were delivered to the U.S. The separation of suspected new elements was carried out in the presence of a citric acid/ammonium buffer solution in a weakly acidic medium (pH ≈ 3.5), using ion exchange at elevated temperatures; fewer than 200 atoms of einsteinium were recovered in the end. Nevertheless, element 99, einsteinium, and in particular 253Es, could be detected via its characteristic high-energy alpha decay at 6.6 MeV. It was produced by the capture of 15 neutrons by uranium-238 nuclei followed by seven beta decays, and had a half-life of 20.5 days. Such multiple neutron absorption was made possible by the high neutron flux density during the detonation, so that newly generated heavy isotopes had plenty of available neutrons to absorb before they could disintegrate into lighter elements. Neutron capture initially raised the mass number without changing the atomic number of the nuclide, and the concomitant beta-decays resulted in a gradual increase in the atomic number:
Two somewhat longer chapters in the book deviate slightly from the rest of the text because they do not contain any image analysis but instead focus on individual persons. Particularly noteworthy is the last part of the second chapter, which movingly describes the life story and the mission of Father Paolo Dall'Oglio, who for Kermani embodies everything he admires about Christianity: a form of unconditional love for one's neighbor that, especially in monks and nuns, goes beyond what a person can achieve without God. Kermani vividly describes the great love for Islam that characterizes Father Paolo and the Mar Musa monastery Paolo founded in Syria, which Kermani characterizes as a place of coexistence between religions. For Father Paolo, his conversion to Islam was not an act of benevolence but rather one that enriched his own life and faith; he is a monk, a disciple of Jesus, who is in love with Islam – as Kermani puts it. Kermani clearly sees this as a model for interfaith dialogue and Christian-Muslim rapprochement. By kidnapping the priest Father Paolo, who loves Islam like no other, the Islamic State has attempted to force Christians to fear Islam as an enemy. Kermani counters this attempt at intimidation with a declaration of his own love for Christianity, responding to Father Paolo and demonstrating how love can be used to counter violence. Kermani also repeatedly explains in his book how he has learned from Christianity—for example, in terms of remembering the suffering and death of others.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.