Everything below concerns peptide stability. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-02-15. Numbers and descriptions here follow the published literature rather than marketing material.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
== Treatment == There have been no controlled studies to define the optimal treatment for BPDCN. Studies on small numbers of individuals with the disease have found that the standard chemotherapy regimens used for the initial induction treatments of AML, acute lymphoblastic leukemia, and high-grade lymphoma give complete remission rates of 77%, 93%, and 80%, respectively, in childhood PBDN and 47%, 77%, and 53%, respectively, in adult PBDN. However, these remissions were short-lived: post-treatment mean times to relapse or death were 12 months for children and 6.8 months for adults. Given these poor remission and survival rates, other treatments have been added to the initial treatment regimens. Studies have shown that the addition of intrathecally administered drugs (administered directly into the spinal canal) as prophylaxis prolongs the period of CNS-free disease and increases overall survival. Hematopoietic stem cell transplantation following initial chemotherapy-induced remission also prolongs these remissions and, it is suggested, offers potential for curing the disease. (A graft-versus-leukemia effect may have contributed to the benefits seen after transplantation.) Studies have not yet determined whether allogenic (i.e. taken from others) or autologous (i.e. taken from self) stem cells achieve better results, although one retrospective study in Japan found that autologous stem cells gave significantly better overall and progression-free survival rates.
There are additives, such as STP Oil Treatment, and some racing oils such as PurOl, PennGrade 1, and Valvoline VR-1, Kixx Hydraulic Oil which are available in the retail market with the necessary amount of ZDDP for engines using increased valve spring pressures.
Systematic botany is part of systematic biology, which is concerned with the range and diversity of organisms and their relationships, particularly as determined by their evolutionary history. It involves, or is related to, biological classification, scientific taxonomy and phylogenetics. Biological classification is the method by which botanists group organisms into categories such as genera or species. Biological classification is a form of scientific taxonomy. Modern taxonomy is rooted in the work of Carl Linnaeus, who grouped species according to shared physical characteristics. These groupings have since been revised to align better with the Darwinian principle of common descent – grouping organisms by ancestry rather than superficial characteristics. While scientists do not always agree on how to classify organisms, molecular phylogenetics, which uses DNA sequences as data, has driven many recent revisions along evolutionary lines and is likely to continue to do so. The dominant classification system is called Linnaean taxonomy. It includes ranks and binomial nomenclature. The nomenclature of botanical organisms is codified in the International Code of Nomenclature for algae, fungi, and plants (ICN) and administered by the International Botanical Congress. Kingdom Plantae belongs to Domain Eukaryota and is broken down recursively until each species is separately classified. The order is: Kingdom; Phylum (or Division); Class; Order; Family; Genus (plural genera); Species.
== Production == Naturally, it is produced in the human placenta by the syncytiotrophoblast. Like any other gonadotropins, it can be extracted from the urine of pregnant women or produced from cultures of genetically modified cells using recombinant DNA technology. In Pubergen, Pregnyl, Follutein, Profasi, Choragon and Novarel, it is extracted from the urine of pregnant women. In Ovidrel, it is produced with recombinant DNA technology.
Sources: en.wikipedia.org
The RNA world is a hypothetical stage in the evolutionary history of life on Earth in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage. Alexander Rich first proposed the concept of the RNA world in 1962, and Walter Gilbert coined the term in 1986. Among the characteristics of RNA that suggest its original prominence are that:
Naltrexone is available and most commonly used in the form of an oral tablet (50 mg). Vivitrol, a naltrexone formulation for depot injection containing 380 mg of the medication per vial, is also available. Additionally, naltrexone subcutaneous implants are available. While these are manufactured in Australia, they are not authorized for use within Australia (but only for export). By 2009, naltrexone implants showed superior efficacy in the treatment of heroin dependence when compared to the oral form.
== Applications == Aerogels are used in a wide range of applications because of their low density, low thermal conductivity, and high surface area. Silica aerogels were the first to be developed commercially and remain the most widely used type. Flexible polymer-based aerogels have been developed to overcome the brittleness of traditional silica aerogels and enable thin, mechanically compliant insulating materials for aerospace and electronic systems. Polyimide aerogel films derived from NASA-developed aerogel technology have been commercialized for such applications; examples include the polyimide aerogel film AeroZero.
Omega-alicyclic fatty acids typically contain an omega-terminal propyl or butyryl cyclic group and are some of the major membrane fatty acids found in several species of bacteria. The fatty acid synthetase used to produce omega-alicyclic fatty acids is also used to produce membrane branched-chain fatty acids. In bacteria with membranes composed mainly of omega-alicyclic fatty acids, the supply of cyclic carboxylic acid-CoA esters is much greater than that of branched-chain primers. The synthesis of cyclic primers is not well understood but it has been suggested that mechanism involves the conversion of sugars to shikimic acid which is then converted to cyclohexylcarboxylic acid-CoA esters that serve as primers for omega-alicyclic fatty acid synthesis
The following year a formal statement was issued to the General Assembly which proclaimed that South Africa had no intention of complying with trusteeship, nor was it obligated to release new information or reports pertaining to its administration. Simultaneously, the South West Africa Affairs Administration Act, 1949, was passed by South African parliament. The new legislation gave white South West Africans parliamentary representation and the same political rights as white South Africans. The UN General Assembly responded by deferring to the International Court of Justice (ICJ), which was to issue an advisory opinion on the international status of South West Africa. The ICJ ruled that South West Africa was still being governed as a mandate; hence, South Africa was not legally obligated to surrender it to the UN trusteeship system if it did not recognise the mandate system had lapsed. Conversely, however, it was still bound by the provisions of the original mandate. Adherence to the original mandate meant South Africa could not unilaterally modify the international status of South West Africa. Malan and his government rejected the court's opinion as irrelevant. The UN formed a Committee on South West Africa, which issued its own independent reports regarding the administration and development of that territory. The Committee's reports became increasingly scathing of South African officials when the National Party imposed its harsh system of racial segregation and stratification—apartheid—on South West Africa.
Sources: en.wikipedia.org
mismatch Also mispairing. An incorrect pairing of nucleobases on complementary strands of DNA or RNA; i.e. the presence in one strand of a duplex molecule of a base that is not complementary (by Watson–Crick pairing rules) to the base occupying the corresponding position in the other strand, which prevents normal hydrogen bonding between the bases. For example, a guanine paired with a thymine would be a mismatch, as guanine normally pairs with cytosine.
Mabel Tolkien was received into the Roman Catholic Church in 1900 despite vehement protests by her Baptist family, which stopped all financial assistance to her. In 1904, when J. R. R. Tolkien was 12, his mother died of acute diabetes at Fern Cottage in Rednal, which she was renting. She was then about 34 years of age, about as old as a person with diabetes mellitus type 1 could survive without treatment—insulin would not be discovered until 1921, two decades later. Nine years after her death, Tolkien wrote, "My own dear mother was a martyr indeed, and it is not to everybody that God grants so easy a way to his great gifts as he did to Hilary and myself, giving us a mother who killed herself with labour and trouble to ensure us keeping the faith." Before her death, Mabel Tolkien had assigned the guardianship of her sons to her close friend, Father Francis Xavier Morgan of the Birmingham Oratory, who was assigned to bring them up as good Catholics. In a 1965 letter to his son Michael, Tolkien recalled the influence of the man whom he always called "Father Francis": "He was an upper-class Welsh-Spaniard Tory, and seemed to some just a pottering old gossip. He was—and he was not.
=== Myomesin 1 === Myomesin 1 is the most researched of the forms of myomesin due to its presence in all striated muscles and that it is the largest of the myomesin class. It is sometimes just simply called myomesin because of it widespread expression. Myomesin 1 is found in mainly on the M4/M4' lines of the M-band. It is encoded by the MYOM1 gene. There are two variants of myomesin 1, one located between the My6 and My7 domains, and the other at the end of the C-terminal after the My13 domain. The prior is known as the embryonic heart (EH)-sequence and the latter, which has only been found in birds, is called the H or S splice variant (H is for heart and S is for skeletal). EH-myomesin can be found during embryonic development of the human heart (later replaced by myomesin 2). As the muscle matures, EH-myomesin is downregulated in favor of myomesin 1 with no genetic variations.
The venous system is the system of veins in the systemic and pulmonary circulations that return blood to the heart. In the systemic circulation the return is of deoxygenated blood from the organs and tissues of the body, and in the pulmonary circulation the pulmonary veins return oxygenated blood from the lungs to the heart. Almost 70% of the blood in the body is in the veins, and almost 75% of this blood is in the small veins and venules. All of the systemic veins are tributaries of the largest veins, the superior and inferior vena cava, which empty the oxygen-depleted blood into the right atrium of the heart. The thin walls of the veins, and their greater internal diameters (lumens) enable them to hold a greater volume of blood, and this greater capacitance gives them the term of capacitance vessels. This characteristic also allows for the accommodation of pressure changes in the system. The whole of the venous system, bar the post-capillary venules is a large volume, low pressure system. The venous system is often asymmetric, and whilst the main veins hold a relatively constant position, unlike arteries, the precise location of veins varies among individuals.
== Chemical composition == The flavonol miquelianin, as well as the alkaloids (+)-(1R)-coclaurine and (−)-(1S)-norcoclaurine, can be found in the leaves of N. nucifera. The plant also contains nuciferine, neferine, and many other benzylisoquinoline alkaloids with medicinal properties.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.