If you have been reading about Tuftsin analogue 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 2025-09-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
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.
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.
=== Other conditions === Previous hand injury Ledderhose disease (plantar fibromatosis) Epilepsy (possibly due to anti-convulsive medication) Higher-than-average fasting blood glucose level Diabetes mellitus HIV Macrophallism Previous myocardial infarction
=== Clotted samples === Coagulation within the sample leads to undercounting, because the analyzer samples the liquid part of the blood, while some of the platelets remain in the tube, trapped in the clot. Overfilling the sample, or inadequately mixing with anticoagulant, may allow small clots to form. Unlike platelet clumps, clots usually cannot be detected by reviewing the peripheral blood smear, but may be detected by probing with wooden sticks, including checking under the cap.
Ukrainian officials criticized the move. In January 2021, Sputnik Light commenced phase I/II trials. In February, Sputnik Light commenced phase III trials. Effectiveness is generally expected to slowly decrease over time. A real-world study with participants aged 60–79 years in Argentina found that the single-injection vaccine is 79% (95% CI, 75–82%) effective in preventing infections, 88% (95% CI, 80–92%) effective against hospitalization, and 85% (95% CI, 75–91%) against death. A phase III clinical trial in Russia also found an efficacy of 79%. According to Nextstrain, lineage B.1.1.317 was the dominant variant in Russia during the study period (5 December 2020 to 15 April 2021), while in Argentina (29 December 2020 to 21 March 2021) lineage N.5 dominated at first, but soon many lineages coexisted in similar proportions. Preliminary data from a study in Moscow in July 2021 indicate that the vaccine is 70% (95% CI, 64–75%) effective against symptomatic disease from the Delta variant for three months after vaccination. In August 2021, RDIF announced that preliminary results from a study on heterologous prime-boost vaccination indicate that it is safe to administer Sputnik Light as the first dose, then the Oxford–AstraZeneca, Moderna or Sinopharm BIBP vaccine as the second dose, as well as the homologous course consisting of Sputnik Light as the second dose. On 11 August 2021, the developers of the Sputnik V vaccine offered its 'Sputnik Light' (Ad26) vaccine to Pfizer for trial against the Delta variant.
Sources: en.wikipedia.org
In selective laser sintering, powdered food materials are heated and bonded together forming a solid structure. This process is completed by bonding the powdered material layer by layer with a laser as the heat source. After a layer is completed with the desired areas bonded, it is then covered by a new unbonded layer of powder. Certain parts of this new unbonded layer are heated by the laser in order to bond it with the structure. This process continues in a vertical upwards manner until the desired food model is constructed. After construction, unbonded material can then be recycled and used to print another food model. Selective laser sintering enables the construction of complex shapes and models and the ability to create different food textures. It is limited by the range of suitable food materials, namely powdered ingredients. Due to this limitation, selective laser sintering has been used primarily for creating sweets/candies.
=== Diabetes === In contrast to previous studies, a recent study of streptozotocin-induced and high-fat diet-induced murine models of diabetes found that the FFAR3-activating drug, AR420626, increased blood plasma insulin levels and stimulated skeletal muscle to take up glucose and thereby improved glucose tolerance test results. Other recent studies have reported that activated FFAR3 may reduce, increase, or have little effect on insulin secretion depending on 1) the levels of ambient glucose and FFAR3 activators studied, (2) human or animal species studied, (3) age of the animals studied, and (4) variations in the proportions of alpha, beta, and delta cells in the pancreatic islets of humans. The role of FFAR3 in human as well as animal models of insulin secretion and diabetes requires further studies.
Sample preparation for mass spectrometry is used for the optimization of a sample for analysis in a mass spectrometer (MS). Each ionization method has certain factors that must be considered for that method to be successful, such as volume, concentration, sample phase, and composition of the analyte solution. Quite possibly the most important consideration in sample preparation is knowing what phase the sample must be in for analysis to be successful. In some cases the analyte itself must be purified before entering the ion source. In other situations, the matrix, or everything in the solution surrounding the analyte, is the most important factor to consider and adjust. Often, sample preparation itself for mass spectrometry can be avoided by coupling mass spectrometry to a chromatography method, or some other form of separation before entering the mass spectrometer. In some cases, the analyte itself must be adjusted so that analysis is possible, such as in protein mass spectrometry, where usually the protein of interest is cleaved into peptides before analysis, either by in-gel digestion or by proteolysis in solution.
=== Project PREPARE === The European PREPARE project aims to fill gaps in nuclear and radiological emergency preparedness identified after the Fukushima accident. The project aims to review emergency response concepts for long-lived releases, to address issues of measurement methods and food safety in the case of transboundary contamination, and to fill gaps in decision support systems (source term reconstruction, improved dispersion modeling, consideration of aquatic dispersion pathways in European river systems).
Sources: en.wikipedia.org
Denny (Denisova 11) is an ~90,000 year old fossil specimen belonging to a ~13-year-old Neanderthal-Denisovan hybrid girl. To date, she is the only first-generation hybrid hominin ever discovered. Denny's remains consist of a single fossilized fragment of a long bone discovered among over 2,000 visually unidentifiable fragments excavated at the Denisova Cave in the Altai Mountains, Russia in 2012. A team of researchers at Oxford University led by Tom Higham used a method of collagen peptide mass fingerprinting, called Zooarchaeology by Mass Spectrometry (ZooMS), and mitochondrial DNA (mtDNA) analysis to identify the fragment as belonging to an archaic human with Neanderthal ancestry. Genomic sequencing and analysis led by paleo-geneticists Viviane Slon and Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology revealed that Denny was the offspring of a Neanderthal mother and a Denisovan father. Additionally, her genome suggests that her father also carried a small degree of Neanderthal ancestry from 300 to 600 generations prior to his lifetime. These surprising genomic data have caused some paleontologists to speculate that interspecies mating between Denisovans and Neanderthals could have occurred with some frequency during several periods of contact over many thousands of years. Additionally, these findings lend support to the hypothesis that similar patterns of admixture, or interbreeding between archaic and modern humans, may have resulted in the partial absorption of Denisovans and Neanderthals into modern human populations.
In case of above-normal intraocular pressure, the mechanism of open-angle glaucoma is believed to be the impeded exit of aqueous humor through the trabecular meshwork, while in closed-angle glaucoma, the iris blocks the trabecular meshwork. Diagnosis is achieved by performing an eye examination. Often, the optic nerve shows an abnormal amount of cupping.
Bone fractures occur because the stress state within collagen fibrils is altered at the locations of mutations, where locally larger shear forces lead to rapid failure of fibrils even at moderate loads because the homogeneous stress state normally found in healthy collagen fibrils is lost. OI is therefore a multi-scale phenomenon, where defects at the smallest levels of tissues (genetic, nano, micro) domino to affect the macro level of tissues.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.