If you have been reading about electrospray ionization and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-10-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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 |
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.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
==== Addition of nitrous and nitric acids ==== Reaction of ethylene oxide with aqueous solutions of barium nitrite, calcium nitrite, magnesium nitrite, zinc nitrite, or sodium nitrite leads to the formation of 2-nitroethanol:
== See also == The FASTQ format, used to represent DNA sequencer reads along with quality scores. The SAM and CRAM formats, used to represent genome sequencer reads that have been aligned to genome sequences. The GVF format (Genome Variation Format), an extension based on the GFF3 format.
In early 1902, British tactics of containment, denial, and harassment finally began to yield results against the Boer guerrillas. The sourcing and co-ordination of intelligence became increasingly efficient with regular reporting from observers in the blockhouses, from units patrolling the fences and conducting "sweeper" operations, and from native Africans in rural areas who increasingly supplied intelligence, as the Scorched Earth policy took effect and they found themselves competing with the Boers for food supplies. Kitchener's forces at last began to affect the Boers' fighting strength and freedom of manoeuvre, and made it harder for the Boers and their families to survive. Despite this success, almost half the Boer fighting strength, around 15,000 men, were still in the field fighting by May 1902. However, Kitchener's tactics were costly: Britain was running out of time, patience, and money needed for the war. The British offered terms of peace on various occasions, notably in March 1901, but all them were rejected by Botha and the "Bitter-enders" among the Boers, who pledged to fight until the bitter end and rejected the demand for surrender or any compromise made by the "Hands-uppers". Their reasons included their hatred of the British, loyalty to their dead comrades, solidarity with fellow Boer commandos, a desire for independence, religious arguments, and fear of captivity or punishment. On the other hand, their women and children were dying in prison camps every day, and independence seemed more and more impossible.
Intrinsic disorder can be either annotated from experimental information or predicted with specialized software. Disorder prediction algorithms can predict intrinsic disorder (ID) propensity with high accuracy (approaching around 80%) based on primary sequence composition, similarity to unassigned segments in protein x-ray datasets, flexible regions in NMR studies and physico-chemical properties of amino acids.
Sources: en.wikipedia.org
29 September Ekranoplan - the Caspian Sea Monster, about the Caspian Sea Monster and ground-effect vehicles; the US accidentally discovered the Ekranoplan in 1970 by the Defense Intelligence Agency; the vehicle was 300 ft long, and 540 tonnes, and twice as big as the B-52; the Soviets called it a 'prototype ship'; the Alekseyev Central Hydrofoil Design Bureau was in Nizhny Novgorod; Igor Vasilevsky and Vladimir Kirillovikh, the chief designer; the company invented the hydrofoil in the late 1950s, winning the Lenin Prize in 1957; hydroaerodynamics engineer Kirril Rozhdestvensky; Victor Dygalo; construction of the KM began in 1963, first tested in October 1966, flown by Vladimir Loginov, reaching 350 mph; designer Dmitri Sinitsyn; Ivan Kapitanets, and its military version; designer Vladimir Bulanov; Günther Jörg of Germany; the possible Spasatel; the Naval Air Warfare Center at Naval Air Station Patuxent River. Narrated by Heather Couper, produced by Grant McKee, directed by Hamish Barbour, made by Ideal World and the Discovery Channel 6 October Homicide in Kennewick, about Kennewick Man, investigated by Jim Chatters; on 6 July 1996 evidence was found; forensic anthropologist Katie Macmillan; anthropological geneticist David Smith of University of California, Davis; forensic anthropologist Doug Owsley; Stephen McNallen of the Asatru Folk Assembly; Samuel George Morton; the Ainu people of Japan. Produced by Eve Kay, directed by Mark Halliley, made by RDF Television with the Discovery Channel
== Class D peptidomimetics == These mechanistic mimetics do not directly recapitulate the side chains or conformation of a peptide but mimic its mode-of-action. Class D peptidomimetics can be directly designed from a small peptide sequence or identified the screening of compound libraries. For example, Nirmatrelvir is an orally-active small molecule drug derived from lufotrelvir, a modified L-peptide.
=== Kidneys === The renal parenchyma is divided into two major structures: the outer renal cortex and the inner renal medulla. Grossly, these structures take the shape of 7 to 18 cone-shaped renal lobes, each containing renal cortex surrounding a portion of medulla called a renal pyramid.
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.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.