Selank raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-08-04. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
However, on the other hand, p53, a well-known tumor suppressor, represses EMT by activating the expression of various microRNAs – miR-200 and miR-34 that inhibit the production of protein ZEB and SNAIL, and thus maintain the epithelial phenotype.
=== Morphology === Polymer morphology generally describes the arrangement and microscale ordering of polymer chains in space. The macroscopic physical properties of a polymer are related to the interactions between the polymer chains.
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=== Spinal disc disease === Spinal disc disease occurs when the nucleus pulposus, a gel-like material in the inner core of the vertebral disc, ruptures. Rupturing of the nucleus pulposus can lead to compression of nerve roots. Symptoms may be unilateral or bilateral, and correlate to the region of the spine affected. The most common region for spinal disk disease is at L4–L5 or L5–S1. The risk for lumbar disc disease is increased in overweight individuals because of the increased compressive force on the nucleus pulposus, and is twice as likely to occur in men. A 2002 study found that lifestyle factors such as night-shift work and lack of physical activity can also increase the risk of lumbar disc disease. Severe spinal-cord compression is considered a surgical emergency and requires decompression to preserve motor and sensory function. Cauda equina syndrome involves severe compression of the cauda equina and presents initially with pain followed by motor and sensory dysfunction. Bladder incontinence is seen in later stages of cauda equina syndrome.
== Further reading == Virtual Textbook of Organic Chemistry Visualizations of the low-temperature crystal structures of alkanes (methane to nonane) Redwood, Boverton (1911). "Paraffin" . Encyclopædia Britannica. Vol. 20 (11th ed.). pp. 752–756.
Sources: en.wikipedia.org
The two substrates of this enzyme are carnitine and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 3-dehydrocarnitine, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is carnitine:NAD+ 3-oxidoreductase.
Researchers at BI discovered that using a buty-2-nyl group resulted in a potent candidate, called BI-1356 (Figure 10). In 2008 BI-1356 was undergoing phase III clinical trials; it was released as linagliptin in May 2011. X-ray crystallography has shown that that xanthine type binds the DPP-4 complex in a different way than other inhibitors: 1. The amino group also interacts with the Glu205, Glu206 and Tyr662 2. The buty-2-nyl group occupies the S1-pocket 3. The uracil group undergoes a π-stacking interaction with the Tyr547 residue 4. The quinazoline group undergoes a π-stacking interaction with the Trp629 residue
Threonine–tRNA ligase 1, cytoplasmic, also called threonyl-tRNA synthetase 1, is an enzyme that in humans is encoded by the TARS1 gene. Like its relatives, TARS2 and TARS3, this enzyme functions as a threonine–tRNA ligase, which means it attaches the animo acid threonine to its corresponding transfer RNA as part of RNA-to-protein translation.
=== Emily Fornell === Emily Fornell (Juliette Angelo) was the daughter of Agent Tobias Fornell and Diane Sterling. Emily first appears during season four, played by Payton Spencer. During season eleven, "Devil's Triad", Emily is kidnapped and subsequently rescued by NSA Analyst Eleanor Bishop, while in season twelve she is visibly distraught following her mother's death. In "Cabin Fever", she enlists Gibbs' assistance when Tobias is arrested for DUI. She later appears in person in the episode "Dead Letter", where she quickly learns about her father being critically wounded by an unknown assassin. Out of anger and grief (especially as it happens just a year after her mother has been murdered), she demands that Gibbs swear to her to find the one who did this and make him pay. She later calls Gibbs requesting his help, as the nurse at the hospital refuses to resuscitate Fornell due to a "do not resuscitate" clause he had written when he was still grieving for her mom's death. While waiting for him to wake up, she attempts to paint his toenails to look like watermelons, but then she notices he is waking up and tries to talk to him. He is only awake for a few moments, but he tells her to tell Gibbs some vital information relating to SISCO regarding stolen cell-phones. This information allows them to track down Jacob Scott (whom they had believed was the man who murdered Terdei and left Fornell under critical condition at the time) who, much to everyone's surprise, has surrendered to NCIS custody at the Navy Yard. In "Family First", she is still waiting for her dad's recovery.
Data from high-throughput chromosome conformation capture experiments, such as Hi-C (experiment) and ChIA-PET, can provide information on the three-dimensional structure and nuclear organization of chromatin. Bioinformatic challenges in this field include partitioning the genome into domains, such as Topologically Associating Domains (TADs), that are organised together in three-dimensional space. Finding the structure of proteins is an important application of bioinformatics. The Critical Assessment of Protein Structure Prediction (CASP) is an open competition where worldwide research groups submit protein models for evaluating unknown protein models.
Sources: en.wikipedia.org
The term "penam" is used to describe the common core skeleton of a member of the penicillins. This core has the molecular formula R-C9H11N2O4S, where R is the variable side chain that differentiates the penicillins from one another. The penam core has a molar mass of 243 g/mol, with larger penicillins having molar mass near 450—for example, cloxacillin has a molar mass of 436 g/mol. 6-APA (C8H12N2O3S) forms the basic structure of penicillins. It is made up of an enclosed dipeptide formed by the condensation of L-cysteine and D-valine. This results in the formations of β-lactam and thiazolidinic rings. The key structural feature of the penicillins is the four-membered β-lactam ring; this structural moiety is essential for penicillin's antibacterial activity. The β-lactam ring is itself fused to a five-membered thiazolidine ring. The fusion of these two rings causes the β-lactam ring to be more reactive than monocyclic β-lactams because the two fused rings distort the β-lactam amide bond and therefore remove the resonance stabilisation normally found in these chemical bonds. An acyl side side chain attached to the β-lactam ring. A variety of β-lactam antibiotics have been produced following chemical modification from the 6-APA structure during synthesis, specifically by making chemical substitutions in the acyl side chain. For example, the first chemically altered penicillin, methicillin, had substitutions by methoxy groups at positions 2' and 6' of the 6-APA benzene ring from penicillin G.
=== Muscle spasticity === Botulinum toxin is used to treat a number of disorders characterized by overactive muscle movement, including cerebral palsy, post-stroke spasticity, post-spinal cord injury spasticity, spasms of the head and neck, eyelid, vagina, limbs, jaw, and vocal cords. Similarly, botulinum toxin is used to relax the clenching of muscles, including those of the esophagus, jaw, lower urinary tract and bladder, or clenching of the anus which can exacerbate anal fissure. Botulinum toxin appears to be effective for refractory overactive bladder.
=== Drug trafficking cases === 1981: Ong Ah Chuan, a Singaporean national, hanged on 20 February 1981 for the trafficking of 209 grams of pure heroin. 1981: Low Hong Eng and her accomplice Tan Ah Tee, both Singaporean nationals, hanged on 9 October 1981 for the joint enterprise of trafficking 459g of heroin. Low was the first woman to be hanged for drug offences in Singapore. 1989: Lau Chi Sing, Hong Kong national, hanged on 17 November 1989 for smuggling 242 grams of heroin. Lau was the first drug mule to be sentenced to death for trafficking narcotics via Changi Airport 1992: Lim Joo Yin and his accomplice Ronald Tan Chong Ngee were both hanged on 3 April 1992 for smuggling heroin. 1994: Cheuk Mei Mei and her accomplice Tse Po Chung, Hongkongers, were hanged on 4 March 1994 for smuggling 2 kg of heroin each. 1994: Johannes van Damme, a Dutch engineer and the first European to be executed in modern-day Singapore, hanged on 23 September 1994 for smuggling 4.32 kg of pure heroin. 1994: Elke Tsang Kai-mong, Hong Kong National, was hanged on 16 December 1994 for smuggling 4 kg of heroin. 1995: Angel Mou Pui Peng, a Macau national hanged on 6 January 1995 for smuggling 4 kg of heroin. 1995: Daniel Chan Chi-pun, Hong Kong national, hanged on 10 March 1995 for smuggling of 464 grams of heroin. 1995: Tong Ching Man and her boyfriend Lam Cheuk Wang, both Hong Kong nationals, hanged on 21 April 1995 for smuggling 1.6 kg and 1.4 kg of heroin respectively. 1995: Poon Yuen Chung, Hong Kong national, hanged on 21 April 1995 for smuggling 3 kg of heroin.
In its native range, mashua is mainly cultivated for its edible tubers. Still, it has ornamental value in the temperate zone because of its trailing habit and showy, bi-colored tubular flowers, which appear in summer and autumn. The sepals are orange-red, while the petals are bright yellow. In areas prone to frost, some protection is required in winter. The cultivar T. tuberosum var. lineamaculatum 'Ken Aslet' has gained the Royal Horticultural Society's Award of Garden Merit.
US decoy attacks by air attacks and naval gunfire the night before Kuwait's liberation were designed to make the Iraqis believe the main coalition ground attack would focus on central Kuwait. For months, American units in Saudi Arabia had been under almost constant Iraqi artillery fire, as well as threats from Scud missiles and chemical attacks. On 24 February 1991, the 1st and 2nd Marine Divisions and the 1st Light Armored Infantry Battalion crossed into Kuwait and headed toward Kuwait City. They encountered trenches, barbed wire, and minefields. However, these positions were poorly defended, and were overrun in the first few hours. Several tank battles took place, but otherwise coalition troops encountered minimal resistance, as most Iraqi troops surrendered. The general pattern was that the Iraqis would put up a short fight before surrendering. However, Iraqi air defenses shot down nine US aircraft. Meanwhile, forces from Arab states advanced into Kuwait from the east, encountering little resistance and suffering few casualties. Despite the successes of coalition forces, it was feared that the Iraqi Republican Guard would escape into Iraq before it could be destroyed. It was decided to send British armored forces into Kuwait 15 hours ahead of schedule, and to send US forces after the Republican Guard. The coalition advance was preceded by a heavy artillery and rocket barrage, after which 150,000 troops and 1,500 tanks began their advance. Iraqi forces in Kuwait counterattacked against US troops, acting on a direct order from Saddam Hussein himself.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
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.