Everything below concerns tuftsin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-09-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
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.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
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.
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.
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.
== Notable academic journal articles == "Intracellular reduction of selenite into glutathione peroxidase... " - US National Library of Medicine - 2000 "Vestibular Dysfunction in DFNB1 Deafness" - US National Library of Medicine - 2011
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deoxyguanosine Abbreviated in shorthand with dG. One of the four standard deoxyribonucleosides used in DNA molecules, consisting of a guanine base with its N9 nitrogen bonded to the C1 carbon of a deoxyribose sugar. Guanine bonded to ribose forms an alternate compound known simply as guanosine, which is used in RNA.
de Lorenzo, Victor; Schmidt, Markus (April 2016). "Synthetic bugs on the loose: containment options for deeply engineered (micro)organisms". Current Opinion in Biotechnology. 38: 90–96. doi:10.1016/j.copbio.2016.01.006. PMID 26874261.
Sources: en.wikipedia.org
the damage to Mr. Banki's life brought about by his lengthy incarceration, occasioned by his confinement, cannot be measured only by the 22 months in which he lost his liberty and which he cannot get back".
==== Endogenous DMT ==== N,N-Dimethyltryptamine (DMT), a psychedelic compound identified endogenously in mammals, is biosynthesized by aromatic L-amino acid decarboxylase (AADC) and indolethylamine-N-methyltransferase (INMT). Studies have investigated brain expression of INMT transcript in rats and humans, coexpression of INMT and AADC mRNA in rat brain and periphery, and brain concentrations of DMT in rats. INMT transcripts were identified in the cerebral cortex, pineal gland, and choroid plexus of both rats and humans via in situ hybridization. Notably, INMT mRNA was colocalized with AADC transcript in rat brain tissues, in contrast to rat peripheral tissues where there existed little overlapping expression of INMT with AADC transcripts. Additionally, extracellular concentrations of DMT in the cerebral cortex of normal behaving rats, with or without the pineal gland, were similar to those of canonical monoamine neurotransmitters including serotonin. A significant increase of DMT levels in the rat visual cortex was observed following induction of experimental cardiac arrest, a finding independent of an intact pineal gland. These results show for the first time that the rat brain is capable of synthesizing and releasing DMT at concentrations comparable to known monoamine neurotransmitters and raise the possibility that this phenomenon may occur similarly in human brains. The first claimed detection of endogenous DMT in mammals was published in June 1965: German researchers F. Franzen and H.
Narrated by Stephen Rashbrook, produced by Nick Catliff, directed by Henry Singer, made by Lion Television and Sandpaper Films. Shown on Monday 7 February 2000 on The Nature of Things in Canada 27 September Near Miss, about ATC, the 1960 New York mid-air collision in December 1960; around 7,500 aircraft visit the three airports each day; LaGuardia Airport has two conjoined runways that operate in a strange mixed way; on 3 April 1998 there was a near miss; USAir Flight 5050 in September 1989; Colombian Avianca Flight 52 in January 1990 approached John F. Kennedy International Airport when running out of fuel, when a 4-hour flight turned into 6 hours due to weather. Narrated by Jack Davenport, directed by Jeremy Llewellyn-Jones, produced by Emma Bowman, made by Windfall Films and The Learning Channel (TLC). On All 4 4 October Curing the Incurable, the strange teratoma cells; Paul R. Sanberg of the University of South Florida; Irving Weissman of Stanford University; pathologist John Goepel; Peter Andrews (biologist); neurosurgeon Douglas Kondziolka of the University of Pittsburgh Medical Center, and stereotactic surgery; John Sinden of ReNeuron; Ann Tsukamoto of CytoTherapeutics. Narrated by David Malone, made by Boa Picture Company 20 December Talking with Aliens, an Equinox Special, with zoologist Denise L. Herzing, made by Pioneer Films
== Structure and reactivity == The structure of α-PMTX consists of 13 amino acid residues with the sequence Arg-Ile-Lys-Ile-Gly-Leu-Phe-Asp-Gln-Leu-Ser-Lys-Leu-NH2. Replacement of the lysine residue at position 12 of α-PMTX with arginine results in β-PMTX. This single amino acid difference appears to be responsible for a difference in potency, as β-PMTX appeared to be five times as potent as α-PMTX in lobster neuromuscular junctions. The location of the three basic residues at positions 1, 3 and 12 was found to be crucial for toxin action. The length of the compound also appeared to be crucial for its function. Analogues of α- and β-PMTX have been synthesized by implementing changes in the amino acid sequence to understand the structure-activity relationship (SAR) with respect to activity for human voltage-gated sodium channel 1.1 (hNaV1.1) and selectivity over other isoforms of human Na+ channels such as hNaV1.2-1.7. 3D models have suggested that β-PMTX may adopt a kinked conformation assisted by its Gly-5 residue and is further stabilised by electrostatic interaction between its negatively charged Asp-8 and positively charged residues Arg-1 and/or Lys-3. This led to the hypothesis that a β-turn-like conformation depending on Gly-5, since it is the most sterically flexible amino acid, could be an important feature of the pharmacologically active conformation. This was tested by replacing Gly-5 with other (β-)turn-favouring residues, but this change was not tolerated.
Schröder (1993, 2002) reviewed the issue of CPA dosage and recommended a dosage of 200 to 300 mg/day for CPA as a monotherapy and a dosage of 100 to 200 mg/day for CPA in combined androgen blockade (that is, CPA in combination with surgical or medical castration). However, the combination of CPA with castration for prostate cancer has been found to significantly decrease overall survival compared to castration alone. Hence, the use of CPA as the antiandrogen component in combined androgen blockade would appear not to be advisable. When used by intramuscular injection to treat prostate cancer, CPA is used at a dosage of 300 mg once a week. The combination of CPA with an estrogen such as ethinylestradiol sulfonate or low-dose diethylstilbestrol has been used as a form of combined androgen blockade and as an alternative to the combination of CPA with surgical or medical castration.
Sources: en.wikipedia.org
Impaired wound healing and thrombocytopenia are possible side effects of sirolimus; therefore, some transplant centers prefer not to use it immediately after the transplant operation, but instead administer it only after a period of weeks or months. Its optimal role in immunosuppression has not yet been determined, and it remains the subject of a number of ongoing clinical trials.
the alternation of late wood and early wood increments within the annual ring; the influence of wood rays on the radial direction; the features of the cell wall structure such as microfibril angle modifications and pits; the chemical composition of the middle lamella. Wood drying may be described as the art of ensuring that gross dimensional changes through shrinkage are confined to the drying process. Ideally, wood is dried to that equilibrium moisture content as will later (in service) be attained by the wood. Thus, further dimensional change will be kept to a minimum. It is probably impossible to completely eliminate dimensional change in wood, but elimination of change in size may be approximated by chemical modification. For example, wood can be treated with chemicals to replace the hydroxyl groups with other hydrophobic functional groups of modifying agents. Among all the existing processes, wood modification with acetic anhydride has been noted for the high anti-shrink or anti-swell efficiency (ASE) attainable without damage to wood. However, acetylation of wood has been slow to be commercialised due to the cost, corrosion and the entrapment of the acetic acid in wood. There is an extensive volume of literature relating to the chemical modification of wood. Drying timber is one method of adding value to sawn products from the primary wood processing industries.
== Visibility to humans == The lens of the human eye and surgically implanted lenses block most radiation in the near UV wavelength range of 300–400 nm; shorter wavelengths are blocked by the cornea. Humans also lack color receptor adaptations for ultraviolet rays. However, the photoreceptors of the human retina are quite sensitive to UVA photons but the lens does not focus this light properly, causing UVA light bulbs to look fuzzy. People lacking a lens (a condition known as aphakia) perceive UVA as whitish-blue or whitish-violet. Near-UV radiation is visible to insects, some mammals, and some birds. Birds have a fourth color receptor for ultraviolet rays; this, coupled with eye structures that transmit more UV gives smaller birds "true" UV vision.
In addition to burying human remains, many human cultures also regularly bury animal remains. Pets and other animals of emotional significance are often ceremonially buried. Most families bury deceased pets on their own properties, mainly in a yard, with a shoe box or any other type of container served as a coffin. The ancient Egyptians are known to have mummified and buried cats, which they considered deities.
This can happen, for example, when a recombinant DNA fragment containing an active promoter becomes located next to a previously silent host cell gene, or when a host cell gene that functions to restrain gene expression undergoes insertional inactivation by recombinant DNA.
Sources: en.wikipedia.org
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
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.