The short version of Selank fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
== Adverse effects == The most common adverse event reported in phase III trials for ripasudil was mild conjunctival hyperemia. Additionally, up to 3.8% of trial participants reported ocular irritation after using the drug with up to 5.7% reporting conjunctival hemorrhage. There were several cases of “abnormal sensation in the eye” reported. On a cellular level, Okumura et al. found that ripasudil produced "guttae-like" formations in ocular endothelial cells post-administration, which was attributed to, "protrusion formation along intracellular borders caused by the reduction in actomyosin contractility of the CECs." However, these morphological changes to the eye were considered transient and therefore quick to reverse, unlike symptoms Fuchs endothelial corneal dystrophy, a disorder for which these short-lived symptoms could be mistaken.
=== Evolution of vertebrate hemoglobin === Scientists agree that the event that separated myoglobin from hemoglobin occurred after lampreys diverged from jawed vertebrates. This separation of myoglobin and hemoglobin allowed for the different functions of the two molecules to arise and develop: myoglobin has more to do with oxygen storage while hemoglobin is tasked with oxygen transport. The α- and β-like globin genes encode the individual subunits of the protein. The predecessors of these genes arose through another duplication event also after the gnathosome common ancestor derived from jawless fish, approximately 450–500 million years ago. Ancestral reconstruction studies suggest that the preduplication ancestor of the α and β genes was a dimer made up of identical globin subunits, which then evolved to assemble into a tetrameric architecture after the duplication. The development of α and β genes created the potential for hemoglobin to be composed of multiple distinct subunits, a physical composition central to hemoglobin's ability to transport oxygen. Having multiple subunits contributes to hemoglobin's ability to bind oxygen cooperatively as well as be regulated allosterically. Subsequently, the α gene also underwent a duplication event to form the HBA1 and HBA2 genes. These further duplications and divergences have created a diverse range of α- and β-like globin genes that are regulated so that certain forms occur at different stages of development.
== Diagnosis == The diagnosis of JIA can be difficult, in part because joint pain in children is so common and may be from many causes other than JIA. The characteristic feature of arthritis is joint swelling which is sometimes – but not always – associated with pain. The presence of joint stiffness is another typical feature, particularly when present in the morning and improving with activity. No single test can confirm a diagnosis of JIA: a combination of presenting signs and symptoms, blood tests, and if necessary medical imaging, is used to make the diagnosis. The blood tests may measure levels of inflammatory markers, as well as the presence of specific immune markers which may include anti-nuclear antibody, HLA-B27, rheumatoid factor and anti–citrullinated protein antibody. These serological markers may be negative in children with JIA, and are often present in healthy children; as such they should not be interpreted in isolation but in the context of the clinical presentation. Many children with JIA have normal blood work. X-rays may be required to ensure that the joint pain and swelling is not from a fracture, cancer, infection, or congenital abnormality. In some cases, fluid from the joint can be aspirated and analysed to assist in making a diagnosis. This test can assist by ruling out other causes of arthritis such as infection.
Sources: en.wikipedia.org
=== Biomedical aspects === Due to increased blood glucose levels, methylglyoxal has higher concentrations in diabetics and has been linked to arterial atherogenesis. Damage by methylglyoxal to low-density lipoprotein through glycation causes a fourfold increase of atherogenesis in diabetics. Methylglyoxal binds directly to the nerve endings and by that increases the chronic extremity soreness in diabetic neuropathy.
Coverage for people with obesity and at least one comorbidity like (elevated LDL-cholesterol, high blood pressure and/or MASLD), will be implemented as early as 1 April 2026. The cost will be significantly higher to taxpayers due to the fact that most insurance companies do not cover it in their formulary. Prior to this change, most Medicaid and CHIP patients only paid $3 a month, the same price for brand-name medication. In May 2026, Amazon Pharmacy announced that it would provide same‑day prescription delivery for the Ozempic pill, used to treat type 2 diabetes.
The term "isotope", Greek for "at the same place", was suggested to Soddy by Margaret Todd, a Scottish physician and family friend, during a conversation in which he explained his ideas to her. He received the 1921 Nobel Prize in Chemistry in part for his work on isotopes.
290 aircraft; more than 20,000 employees; 5.2 million square feet of building space (about 90 football fields). the capacity to handle 115 packages per second (equivalent to 416,000 packages flowing through its facilities every hour);
Sources: en.wikipedia.org
Communication satellite – an artificial satellite used as a telecommunications relay to transmit data between widely separated points on Earth. These are used because the microwaves used for telecommunications travel by line of sight and so cannot propagate around the curve of the Earth. As of 1 January 2021, there were 2,224 communications satellites in Earth orbit. Most are in geostationary orbit 22,200 miles (35,700 km) above the equator, so that the satellite appears stationary at the same point in the sky, so the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track it. In a satellite ground station a microwave transmitter and large satellite dish antenna transmit a microwave uplink beam to the satellite. The uplink signal carries many channels of telecommunications traffic, such as long-distance telephone calls, television programs, and internet signals, using a technique called frequency-division multiplexing (FDM). On the satellite, a transponder receives the signal, translates it to a different downlink frequency to avoid interfering with the uplink signal, and retransmits it down to another ground station, which may be widely separated from the first. There the downlink signal is demodulated and the telecommunications traffic it carries is sent to its local destinations through landlines. Communication satellites typically have several dozen transponders on different frequencies, which are leased by different users.
The jacket harness, also known as AR vest, is a waistcoat (vest) style garment with strong adjustable webbing straps which are adjustable and securely buckled over the shoulders, across the chest and waist, and through the crotch or around each thigh, so that the diver can not slide out under any predictable circumstance. The harness is fitted with several heavy duty D-rings, fixed to the webbing in such a way that the full weight of the diver and all their equipment can be safely supported. A minimum strength for a safe working load of 500 kgf is recommended or required by some codes of practice. A jacket harness is usually provided with webbing straps or a cloth pocket on the back to support the bailout cylinder, may have a variety of pockets to carry tools, and may also carry ditchable or fixed main weights. There are usually several strong D-rings to secure the umbilical and other equipment.
Many marine organisms use chemical defenses to deter predators. For example, some crustaceans and mesograzers, such as the Pseudamphithoides incurvaria, use toxic algae and seaweeds as a shield against predation by covering their bodies in these plants. These plants produce phycotoxins, diterpenes such as pachydictyol-A and dictyol-E, which have been shown to deter predators. Demonstrating this symbiotic relationship are cyanobacteria and shrimp. The snapping shrimp Alpheus frontalis has been observed in utilizing Moorena bouillonii, a cyanobacterium, for shelter and food. M. bouillonii produces compounds that are toxic to other marine organisms and coral but its relationship with A. frontalis demonstrates the use of M. bouillonii as a deterrent and shelter to protect A. frontalis. Other marine organisms produce chemicals endogenously to defend themselves. For example, the finless sole (Pardachirus marmoratus) produces a toxin that paralyzes the jaws of would-be predators. Many zoanthids produce potent toxins, such as palytoxin, which is one of the most poisonous known substances. Some species of these zooanthids are very brightly colored, which may be indicative of aposematic defense. Another defensive measure that involves chemical ecology and marine ecology is the bobtail squid's light organ. The bobtail which is located in Hawaii contains a light organ that houses consumed bacterium Vibrio fischeri, V. fisheri bacterium utilizes quorum sensing to indicate expression for bioluminescence, for down welling light intensity.
=== Marketing ethics issue === Although a "functional" beverage may be marketed as a panacea or a performance-enhancing substance, there is no scientific evidence for any specific health effects of such beverages or for their uniform regulation internationally, as of 2020.
Pakistani forces under "Operation 11 Garaj" killed 10 TTP militants, eight in the Darbi Khel and Batan areas of Khyber District and two in Shakro area of Bajaur district. Eight more militants of HGB groups were killed in an attempt to infiltrate the Pakistan-Afghanistan border in the Datta Khel area of North Waziristan. Pakistan also claimed to have killed a senior TTP commander, Amir Muawiya during an operation (IBO) in Chapri Naryab area of Hangu District. Two insurgents including a suicide bomber were killed by the military in the Hundi Khel area of Bannu District. An IED attack on a police vehicle in Peshawar wounded two personnel, while an attempted ambush on a police convoy in Boya Tehsil led to no casualties. On 3 August, a cleric Mufti Jan Mir, was killed in an explosion in Wana, likely carried out by TTP. A mortar strike by militants on a nomadic camp in Ahmadwam area of Sararogha tehsil killed three and wounded five. Police repelled an attempted militant assault on the Kharai Dara Police Post in Ambar tehsil. A TTP insurgent was killed in an operation in Bara Tehsil while two Lashkar-e-Islam insurgents were killed in Bhutan Sharif area of Tirah Valley. Three militants were killed in a military operation in Lakki Marwat District while two were killed in a police encounter in Peshawar. TTP attacked and damaged a United Bank Limited branch in Dallan area of Hangu District kidnapping two employees. On 5 August, a mortar strike in the Shaktoi Shaga Anay Khel area of South Waziristan wounded a civilian.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
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.