Neurotrophic factor 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.
Last reviewed on 2025-09-26. Where a claim depends on a specific study, the study is described rather than over-claimed.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
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.
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.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
In March 2023, Collins collaborated with Seventy Hyal 2000 to promote their skin boosting product, in which she appeared in a series of online advertisement campaigns as well as on a billboard alongside a phone number, encouraging consumers to call "The Hydration Hotline". In April 2024, Collins collaborated with the cosmetics brand e.l.f., during which she rode a rollercoaster whilst applying the brand's SKIN Bronzing Drops in a video promoting the product. In October 2024, Collins partnered with Superdrug and was appointed "The Beauty Boss" in a campaign promoting the store's seasonal offering and in-store beauty services. Of the collaboration, Collins said she was "so excited about the partnership [...] because since [she was] a young girl [Superdrug] was her go-to place". As part of her role, Collins also fronted a YouTube mini-series in which she explored the companies' products and was joined by special guests including Chloe Sims, whom she had a conversation with whilst receiving beauty treatments. In February 2025, Collins collaborated with the sportswear brand TLC Sport to front their "Find Your Supermodel" campaign and launch a new collection of activewear. The brand subsequently put out a casting call for thirty women to join her for a photoshoot as part of the launch, in which they used no editing or airbrushing on the photos. Collins praised the brand as "inclusive" and encouraged consumers to "empower each other to be [their] best selves".
=== Brand names === Buprenorphine is available under the brand names Cizdol, Brixadi (approved in the US by FDA for addiction treatment in 2023), Suboxone (with naloxone), Subutex (typically used for opioid use disorder), Zubsolv, Bunavail, Buvidal (approved in the UK, Europe and Australia for addiction treatment in 2018), Sublocade (approved in the US in 2018), Probuphine, Temgesic (sublingual tablets for moderate to severe pain), Buprenex (solutions for injection often used for acute pain in primary-care settings), Norspan, and Butrans (transdermal preparations used for chronic pain). In Poland buprenorphine is available under the trade names Bunondol (for pain treatment, when morphine is too little; amounts of 0.2 mg and 0.4 mg) and Bunorfin (for addicts substitution in amount of 2 and 8 mg).
=== LS-SCLC === Chest X-rays are typically the first step to evaluate someone for any type of lung cancer. If images show suspicious spots on the patient's lung, a healthcare provider may order chest CT, PET, needle biopsy or bronchoscopy for further check. It is possible to use bronchoscopic biopsy to diagnose Lung small-cell carcinoma. However, small-cell carcinoma tissue obtained through bronchoscopy is prone to tissue compression and unclear morphology. However, pathologists can stain lesions with immunohistochemistry Ki-67, CD56, TTF-1, CgA, Syn, P63, CK5/6, LCA, and 34βE12 to help, in order to make a differential diagnosis.
==== Animal models ==== The safety of adjuvants are often tested using animal models. Model animals are given a dose of the adjuvant (sometimes comparable to real human/animal vaccines, sometimes higher) by injection, at a site that may or may not be analogous to real-life use. For example, aluminium adjuvants can kill motor neurons when subcutaneously injected at the scruff of a mouse's neck; oil–water suspensions such as pristane produces a precursor to lupus when given to mice by intraperitoneal injection; and arthritis-prone rat strains develop rheumatoid arthritis when injected with 0.2–0.3 mL squalene at the tail. All three examples above concern the classical "grandfathered" adjuvants: if a new adjuvant candidate shows these ill effects in animal testing, it would likely not be further developed, let alone becoming widely used. But more importantly, no effect similar to the above has been found in humans during the decades of their use (including among people genetically predisposed to autoimmunity), showing that animal models are not perfect models – nothing can be a perfect model of another thing, after all.
It would then be possible to detect structures belonging to Type II in our galaxy or in those nearby. Type III structures can also be observed at large cosmological distances. Kardashev recalls that a study was conducted on 3000 sources of the IRAS catalog from the four directions of the sky. Two temperature bands were targeted: from 110 to 120 K and from 280 to 290 K. The analysis showed that the 110–120 K sources are clustered in the Galactic plane and in its center. Kardashev explains that only more powerful observations in the infrared and submillimeter range can reveal possible artificial sources of radiation. He then refers to projects that he has proposed, in particular that of putting into orbit a cryogenic space telescope (the Millimetron Project). According to Kardashev, these results, combined with those of other research on the age of certain cosmic objects, suggest that civilizations dating from 6 to 8 billion years ago may exist in our galaxy. It is likely that they have long since discovered our own civilization, a hypothesis that could answer the question posed by Enrico Fermi when he formulated his paradox: "Where are they?". Without the discovery of artificial sources, however, Shklovsky's theory that civilizations self-destruct as a result of large-scale social conflicts would be proven.
Sources: en.wikipedia.org
== Contraindications == Anyone who is unstable for surgery should not undergo flap surgery. As with most surgeries, people who are sicker may have more difficulties with wound healing. Comorbidities include diabetes, smoking, immunosuppression, and vascular disease.
Thus, protein is not normally used for fuel, and so should not be counted as a food calorie in normal situations; nevertheless, it is usually taken into account. In a calorimeter (and in most diet references) all protein and carbohydrate is worth 4 calories/gram, while fat/oils are worth 9 calories/gram, and various alcohols and other (largely artificial) chemicals are worth fewer. A gram is about 1/25 of an ounce for those more familiar with English measures. The amount of usable calories in food is less than the amount measured in a calorimeter, and requires more care to determine. For instance, starch in plant foods is not readily available to be processed in digestion. Cooked starch (especially when cooked in the presence of moisture) is far more available digestively than raw starch (perhaps 60% vs nearly 100%). Capillary a very small blood vessel. At one end of a capillary is a connection to the body's arteries and at the other end of a capillary is a connection to the body's veins. It is in the capillaries that most gas exchange takes place (oxygen out of the blood into the tissues, and carbon dioxide into the blood). The reverse exchange happens in the capillaries of the lungs. Capillaries are controlled by very small muscles which, together, affect blood pressure very substantially. Those muscles are in turn controlled by, among other things, the presence or absence of insulin (and probably C-peptide) in the blood. Capsaicin a substance found in some plant products, especially hot peppers, which causes human nerves to report a hot sensation.
The ambassador from the Netherlands explained his negative vote as being due to the reference in the preamble to the resolution "to potential harmful effects of the use of depleted uranium munitions on human health and the environment [which] cannot, in our view, be supported by conclusive scientific studies conducted by relevant international organizations." None of the other permanent members of the United Nations Security Council supported the resolution as China was absent for the vote, Russia abstained and the United States voted against the resolution. In September 2008, and in response to the 2007 General Assembly resolution, the UN Secretary General published the views of 15 states alongside those of the International Atomic Energy Agency (IAEA) and World Health Organization (WHO). The IAEA and WHO evidence differed little from previous statements on the issue. The report was largely split between states concerned about depleted uranium's use, such as Finland, Cuba, Japan, Serbia, Argentina, and predominantly NATO members, who do not consider the use of depleted uranium munitions problematic. In December 2008, 141 states supported a resolution requesting that three UN agencies: United Nations Environment Programme (UNEP), WHO and IAEA update their research on the impact of uranium munitions by late 2010—to coincide with the General Assembly's 65th Session, four voted against, 34 abstained and 13 were absent. As before Britain and France voted against the resolution.
On 15 May 2015, the FDA issued a warning that certain SGLT2 diabetes drugs, including canagliflozin, may lead to ketoacidosis, a condition where the body produces higher levels of ketone bodies. The FDA is continuing to investigate the issue, and cautions that patients should not stop taking canagliflozin without first talking to their doctor. On 10 September 2015, the FDA issued a drug safety communication for canagliflozin to address risks for bone fracture and decreased bone density. A label warning for fractures was already included in the Adverse Reactions section; however, the FDA made the addition to the Warnings and Precautions section to reflect new information from a placebo study. They advised that health care professionals should consider fracture risk factors before prescribing canagliflozin, and patients should disclose any bone fracture risk factors to their doctors, but that patients should not stop taking the medication without first talking to their doctor. On 4 December 2015, the FDA issued another safety communication for SGLT2 inhibitors, indicating that it would require new warnings to be added to the canagliflozin label about elevated blood acid levels and urinary tract infections. In June 2016, the FDA strengthened the warning about the risk of acute kidney injury for the type 2 diabetes medicines canagliflozin (Invokana, Invokamet) and dapagliflozin (Farxiga, Xigduo XR).
She saw the base of the Battalion "Vostok" in Gudermes somewhere in that time frame. Chechen soldiers were preparing to go to South Ossetia. It was claimed that they were going to support the peacekeeping mission. At 3:30 am they began preparing for departure with military official reminding them not to forget their passports and military IDs. However, the article does not mention that there was any war in South Ossetia. On 10 August 2008, Moskovskij Komsomolets published a report by journalist who was in Tskhinvali on the night of 7 August. The report states, "There are 1700 peacekeepers here." According to Russian Defence Ministry official, the 1990s ceasefire agreement allowed Russia to station 500 peacekeepers in the conflict zone with 300 additional peacekeepers being reserved to be deployed during emergency. On 10 August 2008, Izvestia published a report by journalist who had been in Tskhinvali. Journalist Yuri Snegirev wrote that he had witnessed Russian military servicemen, who were not peacekeepers, in Tskhinvali bomb shelter on 8 August 2008. On 12 August 2008, Komsomolskaya Pravda reported that in South Ossetia, several soldiers were wounded and one was killed, who were from Tatarstan. Five days before he was killed in South Ossetia, Evgeny Parfenov warned his parents not to call him because it would be hard to reach him by phone. Lieutenant Aleksandr Popov was participating in the exercises on the height near Tskhinvali when his group was requested by the intelligence to reinforce them.
Sources: en.wikipedia.org
Dakin's solution is a dilute solution of sodium hypochlorite (0.4% to 0.5%) and other stabilizing ingredients, traditionally used as an antiseptic, e.g. to cleanse wounds in order to prevent infection. The preparation was for a time called also Carrel–Dakin solution or Carrel–Dakin fluid.
== Memberships == She was a member of the American Chemical Society and the Society of Biological Chemists. She became a Fellow of the American Association for the Advancement of Science in 1947, and was also a Fellow of the American Society of Refrigerating Engineers. She was also a member of the Philadelphia Pathological Society, Sigma Xi, and the Kappa Kappa Gamma sorority.
==== Experimental observations ==== Graphene samples prepared on nickel films, and on both the silicon face and carbon face of silicon carbide, show the anomalous effect directly in electrical measurements. Graphitic layers on the carbon face of silicon carbide show a clear Dirac spectrum in angle-resolved photoemission experiments, and the effect is observed in cyclotron resonance and tunneling experiments.
Activation energies consistent with proline isomerization, which typically has an activation of about 20 kcal/mol. Two-state folding kinetics indicative of both fast-folding and slow-folding populations in the unfolded or denatured state. "Double-jump" assays in which proline-containing proteins are unfolded and refolded, and the population of non-native proline conformations are studied as a function of the extent of folding. Acceleration of the in vitro folding rate by the addition of a prolyl isomerase. Acceleration of the in vitro folding rate in mutant protein variants with one or more proline residues replaced by another amino acid. Not every proline peptide bond is critical to the structure or function of a protein, and not every such bond has a significant influence on folding kinetics, especially trans bonds. Furthermore, some prolyl isomerases have a degree of sequence specificity and therefore may not catalyze the isomerization of prolines in certain sequence contexts.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
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.