Heptapeptide 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 2026-04-20. Numbers and descriptions here follow the published literature rather than marketing material.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
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.
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.
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.
== Discovery == In 1994, Mollereau et al. cloned a receptor that was highly homologous to the classical opioid receptors (OPs) μ-OR (MOP), κ-OR (KOP), and δ-OR (DOP) that came to be known as the Nociceptin Opioid Peptide receptor (NOP). As these “classical” opioid receptors were identified 30 years earlier in the mid-1960s, the physiological and pharmacological characterization of NOP as well as therapeutic development targeting this receptor remain decades behind. Although research on NOP has blossomed into its own sub-field, the lack of widespread knowledge of NOP's existence means that it is commonly omitted from studies that investigate the OP family, despite its promising role as a therapeutic target.
=== Evaluation === The thyroid is examined by observation of the gland and surrounding neck for swelling or enlargement. It is then felt, usually from behind, and a person is often asked to swallow to better feel the gland against the fingers of the examiner. The gland moves up and down with swallowing because of its attachments to the thyroid and cricoid cartilages. In a healthy person the gland is not visible yet is palpable as a soft mass. Examination of the thyroid gland includes the search for abnormal masses and the assessment of overall thyroid size. The character of the thyroid, swellings, nodules, and their consistency may all be able to be felt. If a goitre is present, an examiner may also feel down the neck consider tapping the upper part of the chest to check for extension. Further tests may include raising the arms (Pemberton's sign), listening to the gland with a stethoscope for bruits, testing of reflexes, and palpation of the lymph nodes in the head and neck. An examination of the thyroid will also include observation of the person as a whole, to look for systemic signs such as weight gain or loss, hair loss, and signs in other locations – such as protrusion of the eyes or swelling of the calves in Graves' disease.
Sfinxul is a natural rock formation in the Bucegi Natural Park which is in the Bucegi Mountains of Romania. This rock formation is named for its resemblance to the Sphinx of Giza, and is located at an altitude of 2,216 metres (7,270 feet) within the Babele complex of rock formations.
(1999), "Conditioned Arising Evolves: Variation and Change in Textual Accounts of the Paticca-samupadda Doctrine", Journal of the International Association of Buddhist Studies, 22 (2) Jurewicz, Joanna (2000), "Playing with Fire: The pratityasamutpada from the perspective of Vedic thought", Journal of the Pali Text Society, 26: 77–103 Shulman, Eviatar (2008), "Early Meanings of Dependent-Origination" (PDF), Journal of Indian Philosophy, 36 (2): 297–317, doi:10.1007/s10781-007-9030-8, S2CID 59132368, archived from the original (PDF) on 10 October 2016 Gombrich, Richard (2009), "Chaper 9. Causation and non-random process", What the Buddha Thought, Equinox Jones, Dhivan Thomas (2009), "New Light on the Twelve Nidanas", Contemporary Buddhism, 10 (2): 241–259, doi:10.1080/14639940903239793, S2CID 145413087
==== Sweden ==== In 2008, an 18-year-old Swedish woman died in Stockholm after taking mephedrone. The newspaper Svenska Dagbladet reported the woman went into convulsions and turned blue in the face. Doctors reported she was comatose and suffering from hyponatremia and severe hypokalemia; the woman died one and a half days after the onset of symptoms. An autopsy showed severe brain swelling. Mephedrone was scheduled to be classified as a "dangerous substance" in Sweden even before the woman's death at Karolinska University Hospital on 14 December, but the death brought more media attention to the drug. The possession of mephedrone became classified as a criminal offence in Sweden on 15 December 2008.
Sources: en.wikipedia.org
Aspartic acid was first discovered in 1827 by Auguste-Arthur Plisson and Étienne-Ossian Henry by hydrolysis of asparagine, which had been isolated from asparagus juice in 1806. Their original method used lead hydroxide, but various other acids or bases are now more commonly used instead. There are two forms or enantiomers of aspartic acid. The name "aspartic acid" can refer to either enantiomer or a mixture of two. Of these two forms, only one, "L-aspartic acid", is directly incorporated into proteins. The biological roles of its counterpart, "D-aspartic acid" are more limited. Where enzymatic synthesis will produce one or the other, most chemical syntheses will produce both forms, "DL-aspartic acid", known as a racemic mixture. In the human body, aspartate is most frequently synthesized through the transamination of oxaloacetate. The biosynthesis of aspartate is facilitated by an aminotransferase enzyme: the transfer of an amine group from another molecule such as alanine or glutamine yields aspartate and an alpha-keto acid.
The plutonium present in spent nuclear fuel contains about 12% of 241Pu. Because it converts to 241Am, 241Pu can be extracted and may be used to generate further (isotopically pure) 241Am. However, this process is rather slow: half of the original amount of 241Pu decays to 241Am after about 14 years, and the 241Am amount reaches a maximum after 70 years. The obtained 241Am can be used for generating heavier americium isotopes by further neutron capture inside a nuclear reactor. In a light water reactor (LWR), 79% of neutron captures on 241Am convert to 242Am and 10% to its nuclear isomer 242mAm:
=== Lixisenatide in neurodegenerative diseases === Results from a research work which was done by McClean PL et al. demonstrated that the GLP-1 receptor agonists liraglutide and lixisenatide which are on the market as treatments for type 2 diabetes show promise as potential drug treatments of Alzheimer disease AD. Lixisenatide was equally effective at a lower dose compared to liraglutide in some of the measured parameters after ten weeks of daily intraperitoneal injections with liraglutide (2.5 or 25 nmol/kg) or lixisenatide (1 or 10 nmol/kg) or saline of APP/PS1 mice at an age when amyloid plaques had already formed. When analyzing synaptic plasticity in the hippocampus, LTP was strongly increased in APP/PS1 mice by either drug, with more effectiveness accomplished with lixisenatide. The reduction of synapse numbers seen in APP/PS1 mice was prevented by the two drugs. The amyloid plaque load and dense-core Congo red positive plaque load in the cortex were reduced by both drugs at all doses. The chronic inflammation response (microglial activation) was also reduced by all treatments. Cai HY et al. demonstrated in a study that lixisenatide could reduce amyloid plaques, neurofibrillary tangles and neuroinflammation in the hippocampi of 12-month-old APP/PS1/tau female mice; activation of PKA-CREB signaling pathway and inhibition of p38-MAPK might be the important mechanisms in the neuroprotective function of lixisenatide. So, lixisenatide might have the potential to be developed as a novel therapy for AD.
Russia expert Leon Aron said: "The next target of opportunity is Ukraine – not the entire country, but the Crimean peninsula and Sebastopol, which is home to the Black Sea fleet." The Times wrote on 17 August 2008, "The US intelligence services had been warning that the Russians were preparing for war, but it did not occur to them that fighting would break out just as the world was settling down to watch the Beijing Olympics." Los Angeles Times wrote on 17 August 2008, "A trove of evidence strongly suggests that Russia was preparing the logistics for war well before Aug. 7." Russia began anti-Georgian campaign as early as 2005 and the newspaper noted that Russia began preparing for the war after Georgia submitted a bid to NATO in April 2008 which was "a decisive factor in the decision to escalate the conflict." On 25 August 2008, journalist Matthew Continetti argued that "Whatever the precise sequence of events, however, nothing Saakashvili did provided a reason for Putin to invade Georgia proper; or to bomb Georgian targets in the days after the initial ceasefire; or to charge Saakashvili with crimes against humanity; or to attempt regime change in a democracy that abides by international norms". Continetti also denied the claim that the ultimate blame for the war laid with the United States, NATO and EU.
== Determination == Death was historically believed to be an event that coincided with the onset of clinical death. It is now understood that death is a series of physical events, not a single one, and determination of permanent death is dependent on other factors beyond simple cessation of breathing and heartbeat. Clinical death that occurs unexpectedly is treated as a medical emergency. CPR is initiated. In a United States hospital, a Code Blue is declared and Advanced Cardiac Life Support procedures used to attempt to restart a normal heartbeat. This effort continues until either the heart is restarted, or a physician determines that continued efforts are useless and recovery is impossible. If this determination is made, the physician pronounces legal death and resuscitation efforts stop. If clinical death is expected due to terminal illness or withdrawal of supportive care, often a Do Not Resuscitate (DNR) or "no code" order is in place. This means that no resuscitation efforts are made, and a physician or nurse may pronounce legal death at the onset of clinical death. A patient with working heart and lungs who is determined to be brain dead can be pronounced legally dead without clinical death occurring. However, some courts have been reluctant to impose such a determination over the religious objections of family members, such as in the Jesse Koochin case. Similar issues were also raised by the case of Mordechai Dov Brody, but the child died before a court could resolve the matter.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.