blood-brain barrier comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-01-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
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.
=== Angiogenesis === The formation of new blood vessels is essential for tumor survival and expansion. Intracrines like VEGF and angiogenin regulate angiogenesis within tumor cells and surrounding endothelial cells. Inhibiting intracrine trafficking of angiogenin to the nucleus has been shown to blunt cancer cell proliferation, making this an emerging therapeutic target.
the plastic zone at a crack tip may have a size of the same order of magnitude as the crack size the size and shape of the plastic zone may change as the applied load is increased and also as the crack length increases. Therefore, a more general theory of crack growth is needed for elastic-plastic materials that can account for:
In August 2012, Domino's Pizza changed its name to simply Domino's. At the same time, Domino's introduced a new logo that removed the blue rectangle and text under the domino in the logo, and changed the formerly all-red domino to be blue on the side with two dots and red on the side with one dot. This was done because the company wanted to "expand" menu choices rather than simply rely on its traditional pizza. In April 2022, Domino's Italy franchise operator EPizza SpA filed for bankruptcy at a Milan court after two years of declining sales caused by the COVID-19 lockdowns in Italy. In addition, Domino's Pizza faced competition from local pizza chains and restaurants, which had begun using food delivery app services such as Glovo, Just Eat and Deliveroo. The reason for the failure, however, is mainly that the customer rating of Domino's outlets is very low in Italy, which explains the difficulty of competing with the high quality of Italian pizzas. After the 90-day grace period expired in July 2022, Domino's closed all its Italian stores on 20 July. In 2023, following the Russian invasion of Ukraine, Domino's Russian operations also filed for bankruptcy and Domino's ultimately announced their withdrawal from the country, closing down all of their restaurants shortly after the announcement. On December 12, 2024, Domino's announced that it would transfer its stock to the Nasdaq Global Select Market which took effect on January 2, 2025 at the stock market open. The company retained the ticker symbol "DPZ".
Sources: en.wikipedia.org
=== 23 May === In its evening report, the Ukrainian military reported that there were 25 air strikes and 20 incidents of shelling reported across the country for the day, but no missile attacks. Yevgeny Prigozhin, head of the Wagner Group, promised to transfer control of the Ukrainian city of Bakhmut to the Russian army by 1 June. In an interview, he said that more than 20,000 of his fighters died in the battle for the city, and acknowledged that the Russian military had killed civilians. President Zelenskyy visited naval infantry troops along the Vuhledar-Maryinka defence line in Donetsk Oblast as part of commemorations of the Day of the Ukrainian Marines. He announced that new marine brigades would be added to the Ukrainian military's existing units. The governor of Donetsk Oblast said Russian aerial bombs struck Toretsk, damaging a school but causing no casualties. The Russian Ministry of Defence said that it had forced back "nationalists" who had launched the cross-border attacks in Belgorod Oblast back into Ukraine, adding that its forces had killed more than 70 "Ukrainian terrorists" and destroyed four armored combat vehicles and five pickups. The Governor of Russia's Kursk Oblast said three villages bordering Ukraine were left without power after a drone dropped explosives on an electrical substation. Ukraine accused Russia of blocking access to the port of Pivdennyi to grain exports despite the resumption of the Black Sea Grain Initiative.
=== Natural degradation or clearance === Unfractionated heparin has a half-life of about one to two hours after infusion, whereas low-molecular-weight heparin's half-life is about four times longer. Lower doses of heparin have a much shorter half-life than larger ones. Heparin binding to macrophage cells is internalized and depolymerized by the macrophages. It also rapidly binds to endothelial cells, which precludes the binding to antithrombin that results in anticoagulant action. For higher doses of heparin, endothelial cell binding will be saturated, such that clearance of heparin from the bloodstream by the kidneys will be a slower process.
In conditioned fear models, antalarmin reduced conditioned freezing behavior, suggesting that it blocked the development and expression of conditioned fear, and implicating CRH1 receptors in both processes. Oral administration of antalarmin (3–30 mg/kg) also significantly reduced immobility in a rat model of behavioral despair, with effects similar to the SSRI fluoxetine.
Sources: en.wikipedia.org
=== Canada === Although White Castle has never opened any restaurants in Canada, Canadians have been able to purchase White Castle hamburgers from the frozen foods section in select Canadian grocery and convenience stores since 2015 and more recently at Walmart. For the production of the 2004 film Harold & Kumar Go to White Castle, a full-size outlet was built in Caledon, Ontario, but it was never commissioned or opened to the local public. The store later reopened as Yuppie's Burger, only to go quickly bankrupt. The site was subsequently converted to an Ultramar gas station.
The first time the FDA approved the use of lipid nanoparticles as a drug delivery system was in 2018, when the agency approved the first siRNA drug, Onpattro. Encapsulating the mRNA molecule in lipid nanoparticles was a critical breakthrough for producing viable mRNA vaccines, solving a number of key technical barriers in delivering the mRNA molecule into the host cell. Research into using lipids to deliver siRNA to cells became a foundation for similar research into using lipids to deliver mRNA. However, new lipids had to be invented to encapsulate mRNA strands, which are much longer than siRNA strands. Principally, the lipid provides a layer of protection against degradation, allowing more robust translational output. In addition, the customization of the lipid's outer layer allows the targeting of desired cell types through ligand interactions. However, many studies have also highlighted the difficulty of studying this type of delivery, demonstrating that there is an inconsistency between in vivo and in vitro applications of nanoparticles in terms of cellular intake. The nanoparticles can be administered to the body and transported via multiple routes, such as intravenously or through the lymphatic system. One issue with lipid nanoparticles is that several of the breakthroughs leading to the practical use of that technology involve the use of microfluidics. Microfluidic reaction chambers are difficult to scale up, since the entire point of microfluidics is to exploit the microscale behaviors of liquids.
=== Acute toxicity === Although a low dosis of arenobufagin can be used as a medicine to treat heart rate problems, a high dose can lead to acute heart problems and even death. Arenobufagin is also toxic for hepatocellular carcinoma cells, which is a positive result for the body.
In bioinformatics, the BLOSUM (BLOcks SUbstitution Matrix) matrix is a substitution matrix used for sequence alignment of proteins. BLOSUM matrices are used to score alignments between evolutionarily divergent protein sequences. They are based on local alignments. BLOSUM matrices were first introduced in a paper by Steven Henikoff and Jorja Henikoff. They scanned the BLOCKS database for very conserved regions of protein families (that do not have gaps in the sequence alignment) and then counted the relative frequencies of amino acids and their substitution probabilities. Then, they calculated a log-odds score for each of the 210 possible substitution pairs of the 20 standard amino acids. All BLOSUM matrices are based on observed alignments; they are not extrapolated from comparisons of closely related proteins like the PAM Matrices.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
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.