A practical reference on Research chemical: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-07-24 and is reviewed periodically as new material appears.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
24496Cm + 126C → 256102No* → 252102No + 4 10n Meanwhile, in Dubna, experiments were carried out in 1958 and 1960 aiming to synthesize element 102 as well. The first 1958 experiment bombarded 239Pu and 241Pu with 16O ions. Some alpha decays with energies just over 8.5 MeV were observed, and they were assigned to 251,252,253No, although the team wrote that formation of isotopes from lead or bismuth impurities (which would not produce nobelium) could not be ruled out. While later 1958 experiments noted that new isotopes could be produced from mercury, thallium, lead, or bismuth impurities, the scientists still stood by their conclusion that element 102 could be produced from this reaction, mentioning a half-life of under 30 seconds and a decay energy of (8.8 ± 0.5) MeV. Later 1960 experiments proved that these were background effects. 1967 experiments also lowered the decay energy to (8.6 ± 0.4) MeV, but both values are too high to possibly match those of 253No or 254No. The Dubna team later stated in 1970 and again in 1987 that these results were not conclusive. In 1961, Berkeley scientists claimed the discovery of lawrencium in the reaction of californium with boron and carbon ions. They claimed the production of the isotope 257Lr, and also claimed to have synthesized an alpha-decaying isotope of element 102 that had a half-life of 15 s and alpha decay energy 8.2 MeV. They assigned this to 255No without giving a reason for the assignment.
Promising results of health and medical research are reported: further evidence that breastfeeding is important for the cognitive child development due to its unique ingredients (11 July), trialed hydroxyapatite toothpaste – which can also include fluoride in addition – against caries (18 July), gene therapy eyedrops of Vyjuvek, which was approved in May, against blindness (24 July), the second release from the global WikiGuidelines, a practically oriented guideline on the diagnosis and management of infective endocarditis, demonstrates a novel approach that incorporates uncertainties more than conventional guideline reviews (31 July).
Ghana is a unitary presidential constitutional democracy with a parliamentary multi-party system that is dominated by two parties—the National Democratic Congress (NDC) and the New Patriotic Party (NPP). Ghana alternated between civilian and military governments until January 1993, when the military government gave way to the Fourth Republic of Ghana after presidential and parliamentary elections in late 1992. The 1992 constitution of Ghana divides powers among a commander-in-chief of the Ghana Armed Forces (President of Ghana), parliament (Parliament of Ghana), cabinet (Cabinet of Ghana), council of state (Ghanaian Council of State), and an independent judiciary (Judiciary of Ghana). The government is elected by universal suffrage after every four years. The 2012 Fragile States Index indicated that Ghana is ranked the 67th-least fragile state in the world and the fifth-least fragile state in Africa. Ghana ranked 112th out of 177 countries on the index. Ghana ranked as the 64th-least corrupt and politically corrupt country in the world out of all 174 countries ranked and ranked as the fifth-least politically corrupt country in Africa out of 53 countries in the 2012 Transparency International Corruption Perception Index. Ghana was ranked seventh in Africa out of 53 countries in the 2012 Ibrahim Index of African Governance. The Ibrahim Index is a comprehensive measure of African government, based on variables that reflect the success with which governments deliver essential political goods to its citizens.
Sources: en.wikipedia.org
Next, he co-starred in the action Lucy (2014), about a woman (Scarlett Johansson) who gains psychokinetic abilities when a nootropic drug is absorbed into her bloodstream. Freeman plays Professor Samuel Norman, who helps her research the condition. Producer Virginie Silla wanted Freeman for the part because of his experience in portraying a character of wisdom. "He was the perfect actor", she said. Upon the release of Lucy, critical reception ranged from mixed-to-positive. In the same year Freeman appeared in Dolphin Tale 2, the sequel to 2011's Dolphin Tale, and 5 Flights Up, a comedy-drama. At the end of 2014, Freeman appeared as himself, among other celebrities, in the documentary Lennon or McCartney.
=== Non-human infection === Treponema pallidum has been found in non-human primates in multiple different geographical regions. In Tanzania specifically, T. pallidum geographical distribution closely aligns with the distribution of yaws in humans. The most common strains in NHPs are T. p. pertenue and T. p.endemicum. It is unclear however whether or not these NHP strains can naturally infect humans, but flies have been proposed as possible vectors in an alternative transmission route. Clinically, these infections range from asymptomatic to severe skin ulceration that affect the face or genitalia in these primates. Infection of NHPs is largely reliant on ecological patterns, behaviors, and interactions between the species. There are no current treatments available for infected NHPs.
In August 2024, the SURMOUNT-1 three-year study (176-week treatment period) found that tirzepatide reduced the risk of developing type 2 diabetes by 94% in adults with pre-diabetes and obesity or overweight.
In this bilateral Snowflake, whitish opacities appear throughout the cornea. The stromal lamellae are abnormal and may be separated by amorphous deposits. Moderate to severe vision loss may occur due to corneal opacity. In case of severe vision loss, treatment of choice is penetrating keratoplasty. Peters anomaly: Peters anomaly, also known as iridocorneal adhesions or keratolenticular adhesions, is a posterior corneal defect with an overlying stromal opacity, often accompanied by adherent iris strands (Peters anomaly type 1). The size and density of the opacity can range from a mild to dense central leukoma. Congenital anterior staphyloma: Congenital anterior staphyloma is a rare form of anterior segment dysgenesis that shares similarities with Peters anomaly. It is characterized by an ectatic protrusion of a central opacified cornea lined by uveal tissue. The protrusion extends beyond the plane of the eyelid margins and it can be unilateral or bilateral. Lattice corneal dystrophy: Lattice corneal dystrophy is an autosomal-dominant characterized by amyloid deposition in the corneal stroma. Due to deposits, lattice-like corneal opacities may occur in stroma. Three types of dystrophies are there, type 1, type 2 and type 3. Type 1 is also known as Biber-Haab-Dimmer corneal dystrophy, TGFBI type Lattice Dystrophy, or Classic Lattice Dystrophy. LCD type II is not included in corneal dystrophies. Granular corneal dystrophy: Two types, Type 1 and Type 2 are there. Both have autosomal dominant inheritance.
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
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.