tuftsin 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 2025-12-07. Numbers and descriptions here follow the published literature rather than marketing 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.
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 |
|---|---|---|
| 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 |
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.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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.
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.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
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.
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.
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.
== Side effects == People taking opicapone very commonly (18%) experience dyskinesia. Other common side effects (in 1 to 10% of patients) include dizziness, strange dreams, hallucinations, constipation, dry mouth, orthostatic hypotension (low blood pressure), and muscle spasms. Apart from spasms, these side effects are also known from tolcapone and entacapone. As with entacapone, no relevant liver toxicity has been found in studies. This is in contrast to the first COMT inhibitor tolcapone, which could cause – in some cases lethal – liver insufficiency.
Archives of Biochemistry and Biophysics is a biweekly peer-reviewed scientific journal that covers research in biochemistry and biophysics. It is published by Elsevier. As of 2012, the editors-in-chief were Paul Fitzpatrick (University of Texas Health Science Center at San Antonio), Helmut Sies (University of Düsseldorf), Jian-Ping Jin (Wayne State University School of Medicine), and Henry Jay Forman (University of Southern California). The journal was established in 1942 by Academic Press as the Archives of Biochemistry, obtaining its current name in 1952. It absorbed the journal Molecular Cell Biology Research Communications (formerly section B of Biochemical and Biophysical Research Communications), which was published from 1999 to 2001. An index to authors for the first 75 volumes, covering the period from 1943 to 1958, was published in October 1959.
The ISOLDE COOLer (ISCOOL) is located downstream from the HRS, and extends up to the merging switchyard joining the two mass separator beams. ISCOOL is a general-purpose Radio Frequency Quadrupole Cooler and Buncher (RFQCB), with the purpose of cooling (improving the beam quality) and bunching the RIB from the HRS. Incoming ions collide with the neutral buffer gas, losing their energy, and then are radially confined. The beam is then extracted from ISCOOL.
Glucose uptake is the process by which glucose molecules are transported from the bloodstream into cells through specialized membrane proteins called glucose transporters, primarily via facilitated diffusion or active transport mechanisms: Facilitated Diffusion is a passive process that relies on carrier proteins to transport glucose down a concentration gradient. Secondary Active Transport is transport of a solute in the direction of increasing electrochemical potential via the facilitated diffusion of a second solute (usually an ion, in this case Na+) in the direction of decreasing electrochemical potential. This gradient is established via primary active transport of Na+ ions (a process which requires ATP).
Sources: en.wikipedia.org
81. ArXiv [Preprint]. 2026 Jul 29:arXiv:2605.17186v2. Operator splitting for exploiting linear-rate closure in solving infinite ODE hierarchies. Chang JC. We introduce an operator-splitting method for infinite hierarchies of linear ordinary differential equations (ODEs) indexed by nonnegative integers. When the coupling coefficients depend linearly on the count index, an exact transformation closes the equations on finite count-index windows without an upper-boundary value. For more general hierarchies, Strang splitting applies the linear-rate closure during the linear-rate substeps and a conventional capped solver to the remainder. We derive the closure from generating functions and the method of characteristics and extend it to multi-indexed systems. The derivation requires neither positivity nor mass conservation, so it applies to a wider class of systems than the examplar stochastic models presented here. We discuss branching processes, stochastic predator-prey dynamics, the Schlögl chemical kinetics model, and a telegraph model for gene expression. Through numerical experiments and computational cost analyses we demonstrate that our operator splitting method is typically advantageous for solving large scale systems in terms of memory usage and computational time, while retaining accuracy competitive with finite state projection (FSP) methods. PMCID: PMC13618430
Type I: skin, tendon, vasculature, organs, bone (main component of the organic part of bone) Type II: cartilage (main collagenous component of cartilage) Type III: reticulate (main component of reticular fibers), commonly found alongside type I Type IV: forms basal lamina, the epithelium-secreted layer of the basement membrane Type V: found in the skin (especially around hair follicles and sweat glands) and research suggests it is involved in wound healing and bridging the dermis and epidermis. Also found in the placenta.
=== Cosmetics and pigments === Bismuth oxychloride (BiOCl) is sometimes used in cosmetics, as a pigment in paint for eye shadows, hair sprays, and nail polishes. This compound is found as the mineral bismoclite and in crystal form contains layers of atoms (see figure above) that refract light chromatically, resulting in an iridescent appearance similar to nacre of pearl. It was used as a cosmetic in ancient Egypt and in many places since. Bismuth white (also "Spanish white") can refer to either bismuth oxychloride or bismuth oxynitrate (BiONO3), when used as a white pigment. Bismuth vanadate is used as a light-stable nonreactive paint pigment (particularly for artists' paints), often as a replacement for the more toxic cadmium sulfide yellow and orange-yellow pigments. The most common variety in artists' paints is a lemon yellow, visually indistinguishable from its cadmium-containing alternative.
For example, controlled-release oxycodone (OxyContin) or morphine (MS-Contin) are intended to, via novel delivery mechanisms, permit pain relief for up to twelve hours with an active ingredient which only provides relief for 3 to 6 hours. However, the inherent variability amongst different people with respect to drug metabolism makes this task challenging.
== Pathophysiology == PMD is an idiopathic, non-inflammatory condition. The thinning of the cornea may approach 20% of normal thickness. There may be an increase in the number of mucopolysaccharides in the corneal stroma. The Bowman's layer of the cornea may be absent, irregular, or have ruptured areas.
Sources: pubmed.ncbi.nlm.nih.gov
Large intakes of α-tocopherol result in increased urinary α-CEHC, so this appears to be a means of disposing of excess vitamin E. Alpha-tocopherol transfer protein is coded by the TTPA gene on chromosome 8. The binding site for RRR-α-tocopherol is a hydrophobic pocket with a lower affinity for beta-, gamma-, or delta-tocopherols, or for the stereoisomers with an S configuration at the chiral 2 site. Tocotrienols are also a poor fit because the double bonds in the phytic tail create a rigid configuration that is a mismatch with the α-TTP pocket. A rare genetic defect of the TTPA gene results in people exhibiting a progressive neurodegenerative disorder known as ataxia with vitamin E deficiency (AVED) despite consuming normal amounts of vitamin E. Large amounts of alpha-tocopherol as a dietary supplement are needed to compensate for the lack of α-TTP. The role of α-TTP is to move α-tocopherol to the plasma membrane of hepatocytes (liver cells), where it can be incorporated into newly created very low density lipoprotein (VLDL) molecules. These convey α-tocopherol to cells in the rest of the body. As an example of a result of the preferential treatment, the US diet delivers approximately 70 mg/d of γ-tocopherol, and plasma concentrations are on the order of 2–5 μmol/L; meanwhile, dietary α-tocopherol is about 7 mg/d, but plasma concentrations are in the range of 11–37 μmol/L. Affinity of α-TTP for vitamin E vitamers
== Medical uses == Dezocine is generally administered intravenously (as Dalgan) to relieve post-operative pain in patients. It can also be administered in intramuscular doses, and is given once rather than continuously. It is often administered in post-operative laparoscopy patients as an alternative to fentanyl. Dezocine has potent analgesic effects, and comparable or greater pain-relieving ability than morphine, codeine, and pethidine (meperidine). It is a more effective analgesic than pentazocine, but causes relatively more respiratory depression. Dezocine is a useful drug for the treatment of pain, but side effects such as dizziness limit its clinical application, and it can produce opioid withdrawal syndrome in patients already dependent on other opioids. Because of its high efficacy, dezocine is often administered at a base dose of 0.1 mg/kg. Respiratory depression, a side effect of dezocine, reaches a ceiling at 0.3 to 0.4 mg/kg.
Activated protein C–protein C inhibitor (APC-PCI) is a complex of activated protein C (APC) and protein C inhibitor (PCI). It has been measured in coagulation testing to evaluate coagulation, thrombosis, and other cardiovascular complications. It is a marker of thrombin generation and indicates hypercoagulability or presence of thrombosis. Activated Protein C is a vitamin K-dependent serine protease that cleaves and inactivates Factor Va and Factor VIIIa, thus acting as an anticoagulant. Protein C Inhibitor is a 54-kilodalton glycoprotein of the serpin superfamily. Like other serpins, upon cleavage by PC, PCI undergoes a dramatic conformational rearrangement resulting in a stable covalent bond between the two proteins. The resulting PC-PCI protein dimer lacks enzyme activity and is permanently inactivated, an example of suicide inhibition. Formation of this complex is one of the major means of regulation of protein C activity, so that pro-coagulation and anticoagulant activities are kept in balance.
Prior to founding the Center for Biomedical Mass Spectrometry at Boston University School of Medicine in 1994, Costello was a senior research scientist and the associate director of the National Institutes of Health Research Resource for Mass Spectrometry at Massachusetts Institute of Technology for 20 years. She is a William Fairfield Warren Distinguished Professor and the director of the Center for Biomedical Mass Spectrometry at the Boston University School of Medicine. Costello served as the president of the American Society for Mass Spectrometry (2002–2004), the Human Proteome Organization (2011–2012), and the International Mass Spectrometry Foundation (2014–2018). She currently serves on the board of directors of the US Human Proteome Organization, and the editorial board of Clinical Proteomics.
The medical historian Christoph Gradmann has reconstructed Koch's beliefs regarding the function of tuberculin: the medicine did not kill the bacteria but rather initiated a necrosis of the tubercular tissue, thus "starving" the tuberculosis pathogen. This idea was then outside customary medical theories, as it remains today. The tuberculin scandal was understood as a cautionary tale in regards to testing medicine. Emil von Behring's introduction of his diphtheria antitoxin in 1893 had been preceded by lengthy clinical testing, and the serum was only slowly introduced into practical use, accompanied by a critical discussion among qualified experts. Paul Ehrlich also proceeded with conspicuous caution in 1909 when introducing the first synthetically produced chemotherapeutic agent, Salvarsan, as a cure for an infectious disease, syphilis.
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.
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.