This is a working overview of Selank, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-27 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
=== Excessive sugar intake === Too much sugar intake can negatively impact the body, including damage to collagen. Excess sugar consumption results in glycation that produces AGEs. This occurs naturally, and when too much sugar is consumed, the AGE molecules stick to the collagen molecules turning them stiff, thus damaging them. The process of glycation does not only damage the collagen existing in the body but also makes some alterations to its stability. When an individual consumes excessive amounts of sugar, the glycation process converts collagen into an unstable type 1, which becomes more vulnerable and can be easily broken down, potentially leading to premature aging.
Traditionally, tendons have been considered to be a mechanism by which muscles connect to bone as well as muscles itself, functioning to transmit forces. This connection allows tendons to passively modulate forces during locomotion, providing additional stability with no active work. However, over the past two decades, much research has focused on the elastic properties of some tendons and their ability to function as springs. Not all tendons are required to perform the same functional role, with some predominantly positioning limbs, such as the fingers when writing (positional tendons) and others acting as springs to make locomotion more efficient (energy storing tendons). Energy storing tendons can store and recover energy at high efficiency. For example, during a human stride, the Achilles tendon stretches as the ankle joint dorsiflexes. During the last portion of the stride, as the foot plantar-flexes (pointing the toes down), the stored elastic energy is released. Furthermore, because the tendon stretches, the muscle is able to function with less or even no change in length, allowing the muscle to generate more force. The mechanical properties of the tendon are dependent on the collagen fiber diameter and orientation. The collagen fibrils are parallel to each other and closely packed, but show a wave-like appearance due to planar undulations, or crimps, on a scale of several micrometers.
Super Mario Bros. (originally released in 1985) In Edge's 10th anniversary issue in 2003, GoldenEye 007 (1997) was included as one of the magazine's top ten shooters, along with a note that it was perhaps "the only other game" that should have received a ten out of ten rating. The game had originally been awarded a nine out of ten, with the magazine later stating that "a ten was considered, but eventually rejected". Resident Evil 4, which came second in Edge Presents The 100 Best Videogames, originally obtained a nine, but according to the 100 Best Videogames issue, it came "as near as dammit to the sixth (at the time) Edge ten". The 20th anniversary issue (E258) published in August 2013 carried a feature called "The Ten Amendments", in which the following seven games' scores were retrospectively adjusted to ten-out-of-ten. A rationale was provided for each.
Tolbutamide is a first-generation potassium channel blocker, sulfonylurea oral hypoglycemic medication. This drug may be used in the management of type 2 diabetes if diet alone is not effective. Tolbutamide stimulates the secretion of insulin by the pancreas. It is not routinely used due to a higher incidence of adverse effects compared to newer, second-generation sulfonylureas, such as Glibenclamide. It generally has a short duration of action due to its rapid metabolism, so is safe for use in older people. It was discovered in 1956.
Sources: en.wikipedia.org
A white blood cell differential is a medical laboratory test that provides information about the types and amounts of white blood cells in a person's blood. The test, which is usually ordered as part of a complete blood count (CBC), measures the amounts of the five normal white blood cell types – neutrophils, lymphocytes, monocytes, eosinophils and basophils – as well as abnormal cell types if they are present. These results are reported as percentages and absolute values, and compared against reference ranges to determine whether the values are normal, low, or high. Changes in the amounts of white blood cells can aid in the diagnosis of many health conditions, including viral, bacterial, and parasitic infections and blood disorders such as leukaemia. White blood cell differentials may be performed by an automated analyzer – a machine designed to run laboratory tests – or manually, by examining blood smears under a microscope. The test was performed manually until white blood cell differential analyzers were introduced in the 1970s, making the automated differential possible. In the automated differential, a blood sample is loaded onto an analyzer, which samples a small volume of blood and measures various properties of white blood cells to produce a differential count. The manual differential, in which white blood cells are counted on a stained microscope slide, is now performed to investigate abnormal results from the automated differential, or upon request by the healthcare provider.
Carpipramine (Prazinil, Defekton) is an atypical antipsychotic used for the treatment of schizophrenia and anxiety in France and Japan. In addition to its neuroleptic and anxiolytic effects, carpipramine also has hypnotic properties. It is structurally related to both tricyclics like imipramine and butyrophenones like haloperidol.
includes measurements of radioactivity in plasma, including metabolite correction. From the two-tissue compartment model and by assuming there is only passive diffusion across the blood brain barrier, one obtains:
== History == On 28 September 1969 at approximately 10:58 a.m. local time, near Murchison, Victoria, in Australia, a bright fireball was observed to separate into three fragments before disappearing, leaving a cloud of smoke. About 30 seconds later, a tremor was heard. Many fragments were found scattered over an area larger than 13 km2 (5.0 mi2; 3,200 acres), with individual mass up to 7 kilograms (15.4 lb); one, weighing 680 grams (1.5 lb), broke through a roof and fell in hay. The total collected mass of the meteorite exceeds 100 kilograms (220 lb).
== Epidemiology == Juvenile Idiopathic Arthritis is the most common chronic rheumatic disease of childhood. In high-income countries, yearly incidence has been estimated at 2–20 cases per 100,000 population; prevalence in these areas is estimated at 16–150 cases per 100,000 population. However, there is also a suggestion that these numbers underestimate disease prevalence: one community-based survey of school children in Western Australia reported a prevalence of 400 per 100,000. Overall prevalence is often reported as one per thousand children. Incidence and prevalence data vary across different population and ethnic groups, with lower overall prevalence in Afro-Caribbean and Asian populations. There are also ethnic differences in the frequency of JIA subtypes: for example, oligoarthritis is the most common subtype in European populations, whilst polyarticular disease predominates in many other countries including Costa Rica, India, New Zealand, and South Africa.
Sources: en.wikipedia.org
ersticken/stikken meaning "to choke or suffocate") and still remains in English in the common names of many nitrogen compounds, such as hydrazine and compounds of the azide ion. Finally, it led to the name "pnictogens" for the group headed by nitrogen, from the Greek πνίγειν "to choke". The English word nitrogen (1794) entered the language from the French nitrogène, coined in 1790 by French chemist Jean-Antoine Chaptal (1756–1832), from the French nitre (potassium nitrate, also called saltpetre) and the French suffix -gène, "producing", from the Greek -γενής (-genes, "begotten"). Chaptal's meaning was that nitrogen is the essential part of nitric acid, which in turn was produced from nitre. In earlier times, nitre had been confused with Egyptian "natron" (sodium carbonate) – called νίτρον (nitron) in Greek – which, despite the name, contained no nitrate. The earliest military, industrial, and agricultural applications of nitrogen compounds used saltpetre (sodium nitrate or potassium nitrate), most notably in gunpowder, and later as fertiliser. In 1910, Lord Rayleigh discovered that an electrical discharge in nitrogen gas produced "active nitrogen", a monatomic allotrope of nitrogen. The "whirling cloud of brilliant yellow light" produced by his apparatus reacted with mercury to produce explosive mercury nitride. For a long time, sources of nitrogen compounds were limited. Natural sources originated either from biology or deposits of nitrates produced by atmospheric reactions.
Akram Elias is a businessman from Lebanon living in Washington, D.C., who was the founder and CEO of a private consulting firm in the city called Capital Communications Group. Elias was initiated as a Freemason in 1996, and by 2008 was the Most Worshipful Brother (former Master) of Potomac Lodge No. 5, but had also been raised into stature within the Grand Lodge of Masonic Education and the Grand Lodge of Washington, D. C. The first time he toured Cuba was in 2001, and he made several trips over the years. On one of those trips, in 2004, he personally met Grand Master Collera Venta to discuss Freemasonry in America (e.g., the Americas), and the future of Cuban Freemasonry. In 2004, Alan Gross, a Maryland man from DAI Global, a subcontracting company for USAID, carried a package of electronics equipment and money to Cuba for Marc Wachtenheim. Gross didn't know any Spanish, and was not an expert on Cuba. Gross delivered this package to Grand Master Collera Venta. Gross made five trips to the island between 2004 and 2009, smuggling communications equipment to Collera Venta every time. Certain items that Alan Gross carried into Cuba were BGAN satellite internet links into Jewish communities to circumvent the Cuban firewall. Gross also reached out to Jewish American humanitarian organizations like the Jewish Federations of North America and their chapter in Broward County, Florida, to smuggle contraband items into Jewish communities in Cuba to allow them to communicate to the outside world.
Effects on the skin: skin and the soft tissues immediately underneath the skin undergo greater compression and shear loading than usual, thus explaining the onset of tissue damage so deeply correlated to traumatic ulceration processes. Besides this, the skin of the diabetic foot loses autonomic nervous control and consequently reduced hydration, making it less elastic and thus more vulnerable to the action of increased mechanical stress; effects on tendons and ligaments: protein glycosylation and the resulting collagen abnormalities lead to greater transversal section – i.e., thickening – of tendons and ligaments and a greater coefficient of elasticity. Particularly affected by this process are the Plantar Fascia and Achilles Tendon. Both causes lead to increased stiffness of those structures. Effects on cartilage: similar to what happens to tendons and ligaments, cartilage changes its composition mainly due to the modification of collagen fibers. This increases its stiffness and decreases the range of motion of all joints in the foot and ankle. Effects on muscles: Diabetes mellitus causes severe damage to nerve conduction, thus causing a worsening in the management of the related muscle fibers. As a consequence, both intrinsic and extrinsic muscles of the foot-ankle complex are damaged in structure (reduction of muscle volume) and function (reduction of muscle strength); Effects on the peripheral sensory system: Impaired nerve conduction has a dramatic effect on the peripheral sensory system since it leads to loss of protective sensation under the sole of the foot.
A purported reason was the appearance of high potency cannabis. They believe skunk accounts for between 70% and 80% of samples seized by police (despite the fact that skunk can sometimes be incorrectly mistaken for all types of herbal cannabis). Extracts such as hashish and hash oil typically contain more THC than high potency cannabis infructescences.
Low-velocity: Less than 335 m/s (1,100 ft/s) Low velocity wounds are typical of small caliber handguns. They do not usually cause extensive soft tissue damage, and in the Gustilo open fracture classification are classified as Type 1 or 2 wounds.
Sources: en.wikipedia.org
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.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.