A practical reference on Selank: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-10-27. Anything still debated is marked as such rather than presented as settled.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
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 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.
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.
| 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 |
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
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.
Topography has been applied to different science fields. In neuroscience, the neuroimaging discipline uses techniques such as EEG topography for brain mapping. In ophthalmology, corneal topography is used as a technique for mapping the surface curvature of the cornea. In tissue engineering, atomic force microscopy is used to map nanotopography. In human anatomy, topography is superficial human anatomy. In mathematics the concept of topography is used to indicate the patterns or general organization of features on a map or as a term referring to the pattern in which variables (or their values) are distributed in a space.
Glutamine supplementation was investigated for its possible effects in critically ill people or after abdominal surgery, but the low quality of research prevented conclusions about any effect. Supplementation does not appear to have an effect in infants with significant stomach or intestinal disorders.
=== DuPont and the invention of nylon === Researchers at DuPont began developing cellulose-based fibers, culminating in the synthetic fiber rayon. DuPont's experience with rayon was an important precursor to its development and marketing of nylon. DuPont's invention of nylon spanned an eleven-year period, ranging from the initial research program in polymers in 1927 to its announcement in 1938, shortly before the opening of the 1939 New York World's Fair. The project grew from a new organizational structure at DuPont, suggested by Charles Stine in 1927, in which the chemical department would be composed of several small research teams that would focus on "pioneering research" in chemistry and would "lead to practical applications". Harvard instructor Wallace Hume Carothers was hired to direct the polymer research group. Initially he was allowed to focus on pure research, building on and testing the theories of German chemist Hermann Staudinger. He was very successful, as research he undertook greatly improved the knowledge of polymers and contributed to the science. Nylon was the first commercially successful synthetic thermoplastic polymer. DuPont began its research project in 1927. The first nylon, nylon 66, was synthesized on February 28, 1935, by Wallace Hume Carothers at DuPont's research facility at the DuPont Experimental Station. In response to Carothers' work, Paul Schlack at IG Farben developed nylon 6, a different molecule based on caprolactam, on January 29, 1938. In the spring of 1930, Carothers and his team had already synthesized two new polymers.
Sources: en.wikipedia.org
The surgeon designs the nasolabial flap and sets its central axis at a 45-degree angle from the (long) axis of the nasal dorsum. The shape of the skin flap is cut from the wound template fabricated by the surgeon. An incision is made to the flap (without an anaesthetic injection of epinephrine), which then is elevated and oriented, in an inferior-to-superior direction, between the subcutaneous fat and the muscle fascia. The cutting continues until the skin flap can be freely transposed upon the nasal defect. A Burrow's triangle is excised from the skin between the medial border of the flap and the nasal dorsum; the triangle can be cut either before or after the elevation of the nasolabial. The flap then is bent back (reflected), and can be thinned (cut) under loupe magnification; however, a nasolabial flap cannot be thinned as easily as an axial skin-flap. After the nasolabial flap has been emplaced, the flap donor-site wound is sutured closed. For a wound of the lateral nasal wall that is less than 15 mm wide, the flap donor-site can be closed primarily, with sutures. For a wound wider than 15 mm—especially a wound that comprehends the alar lobule and the lateral wall of the nose—primary closure is not indicated, because such a wound closure imposes excessive stresses upon the skin flap, thereby risking either blanching (whitening) or distortion, or both. Such risks are avoided by advancing (moving) the skin of the cheek towards the nasofacial junction, where it is sutured to the deep tissues.
Methylene blue is used in endoscopic polypectomy as an adjunct to saline or epinephrine, and is used for injection into the submucosa around the polyp to be removed. This allows the submucosal tissue plane to be identified after the polyp is removed, which is useful in determining if more tissue needs to be removed or if there is a high risk for perforation. Methylene blue is also used as a dye in chromoendoscopy, and is sprayed onto the mucosa of the gastrointestinal tract to identify dysplasia, or pre-cancerous lesions. Intravenously injected methylene blue is readily released into the urine. In surgeries such as sentinel lymph node dissections, methylene blue can be used to visually trace the lymphatic drainage of tested tissues. Similarly, methylene blue is added to bone cement in orthopedic operations to provide easy discrimination between native bone and cement. Additionally, methylene blue accelerates the hardening of bone cement, increasing the speed at which bone cement can be effectively applied. Methylene blue is used as an aid to visualisation/orientation in several medical devices, including a surgical sealant film. It can also be used during gastrointestinal surgeries (such as bowel resection or gastric bypass) to test for leaks. It is sometimes used in cytopathology, in mixtures including Wright-Giemsa and Diff-Quik. It confers a blue color to both nuclei and cytoplasm, and makes the nuclei more visible. When methylene blue is "polychromed" (oxidized in solution or "ripened" by fungal metabolism, as originally noted in the thesis of Dr. D. L.
Somalia's network of roads is 22,100 km (13,700 mi) long. As of 2000, 2,608 km (1,621 mi) streets are paved and 19,492 km (12,112 mi) are unpaved. A 750 km (470 mi) highway connects major cities in the northern part of the country, such as Bosaso, Galkayo and Garowe, with towns in the south. Sixty-two airports across Somalia accommodate aerial transportation; seven of these have paved runways. Among the latter, four airports have runways of over 3,047 metres (9,997 ft); two are between 2,438 and 3,047 m (7,999 and 9,997 ft) and one is 1,524 to 2,437 m (5,000 to 7,995 ft) long. There are fifty-five airports with unpaved landing areas. One has a runway of over 3,047 m; four are between 2,438 m and 3,047 m in length; twenty are 1,524 m to 2,437 m; twenty-four are 914 m to 1,523 m; and six are under 914 metres (2,999 ft). Major airports in the nation include the Aden Adde International Airport in Mogadishu, the Hargeisa International Airport in Hargeisa, the Kismayo Airport in Kismayo, the Baidoa Airport in Baidoa, and the Bender Qassim International Airport in Bosaso. Established in 1964, Somali Airlines was the flag carrier of Somalia. It suspended operations during the civil war. However, a reconstituted Somali government later began preparations in 2012 for an expected relaunch of the airline, with the first new Somali Airlines aircraft scheduled for delivery by the end of December 2013. According to the Somali Chamber of Commerce and Industry, the void created by the closure of Somali Airlines has since been filled by various Somali-owned private carriers.
When cold air damming occurs, it allows for cold air to surge toward the equator in the affected area. In calm, non-stormy situations, the cold air will advance unhindered until the high-pressure area can no longer exert any influence because of a lack of size or its leaving the area. The effects of cold air damming become more prominent (and also more complicated) when a storm system interacts with the spreading cold air. The effects of cold air damming east of the Cascades in Washington are strengthened by the bowl or basin-like topography of Eastern Washington. Cold Arctic air flowing south from British Columbia through the Okanogan River valley fills the basin, blocked to the south by the Blue Mountains. Cold air damming causes the cold air to bank up along the eastern Cascade slopes, especially into the lower passes, such as Snoqualmie Pass and Stevens Pass. Milder, Pacific-influenced air moving east over the Cascades is often forced aloft by the cold air in the passes, held in place by cold air damming east of the Cascades. As a result, the passes often receive more snow than higher areas in the Cascades, which supports skiing at Snoqualmie and Stevens passes.
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.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.