Everything below concerns TKPRPGP. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-10-26. 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.
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.
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.
| 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 |
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
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.
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.
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.
Critical fission reactors are the most common type of nuclear reactor. In a critical fission reactor, neutrons produced by fission of fuel atoms are used to induce yet more fissions, to sustain a controllable amount of energy release. Devices that produce engineered but non-self-sustaining fission reactions are subcritical fission reactors. Such devices use radioactive decay or particle accelerators to trigger fissions. Critical fission reactors are built for three primary purposes, which typically involve different engineering trade-offs to take advantage of either the heat or the neutrons produced by the fission chain reaction:
In another case, a man ingested 200 castor beans mixed with juice in a blender and survived. Victims often manifest nausea, diarrhea, fast heart rate, low blood pressure, and seizures persisting for up to a week. Blood, plasma, or urine ricin or ricinine concentrations may be measured to confirm diagnosis. The laboratory testing usually involves immunoassay or liquid chromatography-mass spectrometry.
== Mechanism of action == Chlorothalonil reacts with glutathione giving an glutathione adduct with elimination of HCl. Its mechanism of action is similar to that of trichloromethyl sulfenyl fungicides such as captan and folpet.
On August 23, 1879, 26 members of the Christian Scientists' Association were granted a charter to form the Church of Christ (Scientist). Services were held in people's homes in Lynn and later in Hawthorne Hall, Boston. On January 31, 1881, Eddy was granted a charter to form the Massachusetts Metaphysical College to teach "pathology, ontology, therapeutics, moral science, metaphysics, and their application to the treatment of disease." The college lived wherever Eddy did; a new sign appeared on 8 Broad Street. In October 1881 there was a revolt. Eight church members resigned, signing a document complaining of Eddy's "frequent ebullitions of temper, love of money, and the appearance of hypocrisy." Only a few students remained, including Calvin Frye, who became Eddy's most loyal personal assistant. They appointed Eddy pastor of the church in November 1881, and drew up a resolution in February 1882 that she was "the chosen messenger of God to the nations." Despite the support, the resignations ended Eddy's time in Lynn. The church was struggling and her reputation had been damaged by the disputes. By now 61 years old, she decided to move to Boston, and in early 1882 rented a house at 569 Columbus Avenue, a silver plaque announcing the arrival of the Massachusetts Metaphysical College.
Trauma to the region Inflammation (bug bites, acne) Varicose veins Infections Tumors (malignant or benign) Diseases of connective tissue Hypercalcemia Hyperphosphatemia Calcinosis cutis is associated with systemic sclerosis.
Sources: en.wikipedia.org
On the other hand, significantly more patients drop off from the antidepressant treatment than from psychotherapy, likely because of the side effects of antidepressants. Successful psychotherapy appears to prevent the recurrence of depression even after it has been terminated or replaced by occasional "booster" sessions. The same degree of prevention can be achieved by continuing antidepressant treatment. Two studies suggest that the combination of psychotherapy and medication is the most effective way to treat depression in adolescents. Both TADS (Treatment of Adolescents with Depression Study) and TORDIA (Treatment of Resistant Depression in Adolescents) showed very similar results. TADS resulted in 71% of their teen subjects having "much" or "very much" improvement in mood over the 61% with medication alone and 43% with CBT alone. Similarly, TORDIA showed a 55% improvement with CBT and drugs versus a 41% with drug therapy alone. However, a more recent meta-analysis of 34 trials of 14 drugs used with children and adolescents found that only fluoxetine produced significant benefit compared to placebo, with a medium-sized effect (standardize mean difference = .5).
The CMP continued in later years to replace some of Guimard's designs with more sober entrances by Cassien-Bernard, often a plain balustrade in white stone, for example at Gare de l'Est, Madeleine, Montparnasse, and Saint-François-Xavier. Modernization beginning after World War I also led to the demolition of many, especially the more elaborate. Shortly before World War II, it was suggested that those remaining should be scrapped for their metal. Art Nouveau had only briefly been in fashion and only became popular once more in the last quarter of the 20th century.
Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage. Disturbances in the normal redox state of cells can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins, lipids, and DNA. Oxidative stress from oxidative metabolism causes base damage, as well as strand breaks in DNA. Base damage is mostly indirect and caused by the reactive oxygen species generated, e.g., O−2 (superoxide radical), OH (hydroxyl radical) and H2O2 (hydrogen peroxide). Short-term oxidative stress is required to initiate stress response processes in plants.
=== Gallbladder and biliary risk === Semaglutide treatment is associated with an increased risk of biliary disease, specifically gallstones (cholelithiasis). While initially thought to be solely a byproduct of rapid weight loss, the exact mechanism may involve reduced gallbladder motility and changes in bile acid composition.
== Publications == Eltenton, G. C. (1938). "Direct Evidence for the N2H+ Ion in the Discharge Reaction between N2 and H2". Nature. 141 (3578): 975–976. Bibcode:1938Natur.141..975E. doi:10.1038/141975b0. S2CID 4041283. Eltenton, G. C. (1942). "The Detection of Free Radicals by Means of a Mass Spectrometer". Journal of Chemical Physics. 10 (6): 403. Bibcode:1942JChPh..10..403E. doi:10.1063/1.1723738. Eltenton, G. C. (1947). "The Study of Reaction Intermediates by Means of a Mass Spectrometer Part I. Apparatus and Method". Journal of Chemical Physics. 15 (7): 455–481. Bibcode:1947JChPh..15..455E. doi:10.1063/1.1746565. Eltenton, G. C. (1954). "Some instruments for quality control in petroleum refineries". Journal of Applied Chemistry. 4 (5): 245–256. doi:10.1002/jctb.5010040503.
Sources: en.wikipedia.org
=== Depression === There is evidence suggesting that activation of the AMPA receptor, downstream activation of mammalian target of rapamycin (mTOR), and upregulation of brain-derived neurotrophic factor (BDNF) are central to the antidepressant effects of certain NMDA receptor antagonists such as ketamine. Blockage of the AMPA receptor nullifies the antidepressant actions of ketamine in rodents. By potentiating the effect of endogenous glutamate at the AMPA receptor, osavampator more directly influences AMPA receptor-mediated transcription. The potential use of osavampator as a non-psychotomimetic antidepressant is cited as reason for its investigation. Initial research found that osavampator, unlike ketamine, did not induce hyperlocomotor responses in rats. However, a later human trial investigating the central nervous system (CNS) stimulatory properties and tolerability of osavampator reported that although the CNS stimulatory properties of the drug were less pronounced than other psychostimulants, osavampator did appear to possess at least some stimulant-like effects. No severe adverse effects were noted in the trial. AMPA receptor agonists are likely not viable for clinical applications as they present a risk of inducing seizures and overexcitation-induced neurotoxicity at doses close to their therapeutic window. Osavampator possesses minimal direct AMPA agonist properties. Osavampator provides a 419-fold safety margin against convulsions relative to therapeutic doses in rats.
27 May A new compact CRISPR gene editing tool better suited for therapeutic (temporary) RNA editing than Cas13 is reported, Cas7-11, – of which an early version was used for in vitro editing in 2021. Science and the 2022 Russian invasion of Ukraine:According to a news report academics in Russia are compiling or circulating a list of researchers who have supported Russia's invasion to prevent them from being elected to the Russian Academy of Sciences. An editorial published in a journal notes that remote surgery and types of videoconferencing for sharing expertise (e.g. ad hoc assistance) have been and could be used to support doctors in Ukraine (3 May). A forum contribution analyzes Russian users' reactions to the Bucha massacre on social media – on nationalist Telegram channels (9 May). The FAO estimates that "at least 20 percent of Ukraine's winter crops" "may not be harvested or planted" (13 May). A preprint estimates potential impacts of the EU embargoing fossil fuels from Russia, suggesting implementing such via a partial embargo with tariffs may be beneficial (25 May). 28 May – A new direct air capture system using isophorone diamine is demonstrated, able to remove carbon dioxide with 99% efficiency and more than twice as fast as existing systems. 30 May – Frontier is announced by Oak Ridge National Laboratory as the world's first exascale supercomputer. 31 May – Success of record-long (3 days rather than usually <12 hours) of human transplant organ preservation with machine perfusion of a liver is reported.
== Applications == HPTLC finds extensive application in various fields, including pharmaceutical industries, clinical chemistry, forensic chemistry, biochemistry, cosmetology, food and drug analysis, environmental analysis, and more, owing to its numerous advantages. It distinguishes itself by being the only chromatographic method capable of presenting results as images and offers simplicity, cost-effectiveness, parallel analysis of samples, high sample capacity, rapid results, and the option for multiple detection methods. Le Roux's research team assessed HPTLC for determining salbutamol serum levels in clinical trials and concluded that it is a suitable method for analyzing serum samples. HPTLC has proven valuable in lichenology for analyzing and identifying lichen substances. Compared to standard TLC, the technique offers several advantages for screening lichen compounds: it allows twice as many samples to be run on one plate, requires significantly less solvent (4 mL per plate versus 250 mL), completes chromatographic separation in under 10 minutes per plate, and can detect substances at much lower concentrations. The method's increased sensitivity has enabled detection of previously unidentified lichen compounds and revealed greater chemical variation within lichen species. Since the early 1990s, HPTLC has been used as an improved alternative to standard TLC for routine screening of lichen substances, though proper plate drying is critical as the technique is more sensitive to atmospheric humidity than standard TLC.
Crosslinking of peptidyl moieties of adjacent glycan strands is a two-step reaction. The first step involves the cleavage of the D-alanyl-D-alanine bond of a peptide unit precursor acting as carbonyl donor, the release of the carboxyl-terminal D-alanine, and the formation of the acyl-enzyme. The second step involves the breakdown of the acyl-enzyme intermediate and the formation of a new peptide bond between the carbonyl of the D-alanyl moiety and the amino group of another peptide unit. Most discussion of DD-peptidase mechanisms revolves around the catalysts of proton transfer. During formation of the acyl-enzyme intermediate, a proton must be removed from the active site serine hydroxyl group and one must be added to the amine leaving group. A similar proton movement must be facilitated in deacylation. The identity of the general acid and base catalysts involved in these proton transfers has not yet been elucidated. However, the catalytic triad tyrosine, lysine, and serine, as well as serine, lysine, serine have been proposed.
The first true chromatography is usually attributed to the Russian-Italian botanist Mikhail Tsvet. Tsvet applied his observations with filter paper extraction to the new methods of column fractionation that had been developed in the 1890s for separating the components of petroleum. He used a liquid-adsorption column containing calcium carbonate to separate yellow, orange, and green plant pigments (what are known today as xanthophylls, carotenes, and chlorophylls, respectively). The method was described on December 30, 1901, at the 11th Congress of Naturalists and Doctors (XI съезд естествоиспытателей и врачей) in Saint Petersburg. The first printed description was in 1903, in the Proceedings of the Warsaw Society of Naturalists, section of biology. He first used the term chromatography in print in 1906 in his two papers about chlorophyll in the German botanical journal, Berichte der Deutschen Botanischen Gesellschaft. In 1907 he demonstrated his chromatograph for the German Botanical Society. Mikhail's surname "Цвет" means "color" in Russian, so there is the possibility that his naming the procedure chromatography (literally "color writing") was a way that he could make sure that he, a commoner in Tsarist Russia, could be immortalized. In a 1903 lecture (published in 1905), Tsvet also described using filter paper to approximate the properties of living plant fibers in his experiments on plant pigments—a precursor to paper chromatography.
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.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.