Everything below concerns blood-brain barrier. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-02-02. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
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.
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.
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.
If the protactinium remains in the reactor, small amounts of uranium-232 are also produced, which has the strong gamma emitter thallium-208 in its decay chain. Similar to uranium-fueled designs, the longer the fuel and fertile material remain in the reactor, the more of these undesirable elements build up. In the envisioned commercial thorium reactors, high levels of uranium-232 would be allowed to accumulate, leading to extremely high gamma-radiation doses from any uranium derived from thorium. These gamma rays complicate the safe handling of a weapon and the design of its electronics; this explains why uranium-233 has never been pursued for weapons beyond proof-of-concept demonstrations. While the thorium cycle may be proliferation-resistant with regard to uranium-233 extraction from fuel (because of the presence of uranium-232), it poses a proliferation risk from an alternate route of uranium-233 extraction, which involves chemically extracting protactinium-233 and allowing it to decay to pure uranium-233 outside of the reactor. This process is an obvious chemical operation which is not required for normal operation of these reactor designs, but it could feasibly happen beyond the oversight of organizations such as the International Atomic Energy Agency (IAEA), and thus must be safeguarded against.
Machine learning algorithms require large amounts of data. The techniques used to acquire this data have raised concerns about privacy, surveillance and copyright. AI-powered devices and services, such as virtual assistants and IoT products, continuously collect personal information, raising concerns about intrusive data gathering and unauthorised access by third parties. The loss of privacy is further exacerbated by AI's ability to process and combine vast amounts of data, potentially leading to a surveillance society where individual activities are constantly monitored and analysed without adequate safeguards or transparency. Sensitive user data collected may include online activity records, geolocation data, video, or audio. For example, in order to build speech recognition algorithms, Amazon has recorded millions of private conversations and allowed temporary workers to listen to and transcribe some of them. Opinions about this widespread surveillance range from those who see it as a necessary evil to those for whom it is clearly unethical and a violation of the right to privacy. AI developers argue that this is the only way to deliver valuable applications and have developed several techniques that attempt to preserve privacy while still obtaining the data, such as data aggregation, de-identification and differential privacy. Since 2016, some privacy experts, such as Cynthia Dwork, have begun to view privacy in terms of fairness.
The same day, Hitler met with Chamberlain and demanded the swift takeover of the Sudetenland by Nazi Germany under threat of war. Czechoslovakia, Hitler claimed, was slaughtering the Sudeten Germans. Chamberlain referred the demand to the British and French governments, both of which accepted. The Czechoslovak government resisted by arguing that Hitler's proposal would ruin the nation's economy and ultimately lead to German control of all of Czechoslovakia. The United Kingdom and France issued an ultimatum and made a French commitment to Czechoslovakia contingent upon its acceptance. On 21 September, Czechoslovakia capitulated. The next day, however, Hitler added new demands that insisted for the claims of Poland and Hungary to be satisfied as well. Romania was also invited to share in the division of Carpathian Ruthenia but refused because it was an ally of Czechoslovakia (see Little Entente). The Czechoslovak capitulation precipitated an outburst of national indignation. In demonstrations and rallies, Czechs and Slovaks called for a strong military government to defend the integrity of the state. A new cabinet, under General Jan Syrový, was installed, and on 23 September 1938, a decree of general mobilization was issued. The Czechoslovak Army was modern, had an excellent system of frontier fortifications and was prepared to fight. The Soviet Union announced its willingness to come to Czechoslovakia's assistance. Beneš, however, refused to go to war without the support of the Western powers.
=== Food industry === The calcium sulfate hydrates are used as a coagulant in products such as tofu. For the FDA, it is permitted in cheese and related cheese products; cereal flours, bakery products, frozen desserts, artificial sweeteners for jelly & preserves, condiment vegetables, and condiment tomatoes, and some candies. It is known in the E number series as E516, and the UN's FAO knows it as a firming agent, a flour treatment agent, a sequestrant, and a leavening agent.
Sources: en.wikipedia.org
== Academic career == He received the Standard Oil Foundation for Excellence in Undergraduate Teaching Award in 1970; the Tanner Award for Excellence in Undergraduate Teaching in 1986; and he was elected by students to membership in the Society of the Golden Fleece in 1989. He collaborated with 55 M.S. and Ph.D. colleagues resulting in over 160 referred publications in journals and edited volumes. Following Hiskey's retirement in 1996, the department created the Richard G. Hiskey Graduate Student Fellowship dedicated to the recruitment and retention of outstanding graduate students. Hiskey received Outstanding Alumnus Awards from Kansas State University in 1973, Wayne State University in 1978, Emporia State University in 1979, and the UNC-CH General Alumni Association Faculty Service Award in 1992. He also was a John Simon Guggenheim Foundation Fellow and a Kenan Research Leave Fellow in 1970–71 at the Max Planck Institute for Cell Chemistry. Hiskey's initial research concerned the development of methods for the production of "mixed sulfides" and the features which stabilized or destabilized these molecules. Mixed disulfides occur in the folding and stabilization of proteins via cystine-cystine interactions. Pursuit of the synthesis of insulin led to the development of methods for the production of mixed disulfides containing two or more cystine residues differently S-protected. The second major phase of Hiskey's research program concerned the role of protein-bound X-Carboxyglutamic (GLA) residues in blood clot formation.
Occasionally a radiologic diagnosis of disc degeneration is made incidentally when a cervical X-ray, chest X-ray, or abdominal X-ray is taken for other reasons and the abnormalities of the vertebral column are recognized. The diagnosis of DDD is not a radiologic diagnosis, since the interpreting radiologist is not aware whether there are symptoms. Typical radiographic findings include disc space narrowing, displacement of vertebral bodies, fusion of adjacent vertebral bodies, and development of bone in adjacent soft tissue (osteophyte formation). An MRI is typically reserved for those with symptoms, signs, and X-ray findings suggesting a need for surgical intervention. Treatment may include physical therapy for pain relief, ROM (range of motion), and appropriate muscle/strength training, with emphasis on correcting abnormal posture, assisting the paravertebral (paraspinous) muscles in stabilizing the spine, and core muscle strengthening; stretching exercises; massage therapy; oral analgesia with non-steroidal anti-inflammatory agents (NSAIDS); and topical analgesia with lidocaine, ice, and heat. Immediate surgery may be indicated if the symptoms are severe or sudden in onset, or suddenly worsen. Elective surgery may be indicated after six months of conservative therapy with unsatisfactory relief of symptoms.
=== Diarrhea === Opium tincture is indicated for the treatment of severe fulminant (intense, prolific) diarrhea that does not respond to standard therapy (e.g., Imodium or Lomotil). The usual starting dose is 0.3 mL to 0.6 mL (about six to 12 drops) in a glass of water or juice four times a day. Refractory cases (such as diarrhea resulting from the complications of HIV/AIDS) may require higher than normal dosing, for example, 1 to 2 mL every 3 hours, for a total daily dose of up to 16 mL a day. In terminal diseases, there is no ceiling dose for opium tincture; the dose is increased slowly until diarrhea is controlled.
Sources: en.wikipedia.org
== Early life and education == Abdel Fattah al-Burhan was born in 1960 in the village of Gandatu in northern Sudan, to a Ja'ali family. Al-Burhan studied elementary and intermediate level in his village school, and later moved to Shendi to complete his education before joining the Sudanese Military College.
=== Notes === "Inglorious Bastards" features uncredited vocals from DJ Clue. "M.T.B.T.T.F." stands for "Mike Tyson Blow to the Face". Due to sample clearance issues with "So Be It", a "Pt. II" remix with a different instrumental was uploaded onto streaming platforms in its place upon the album's release. A few hours later, the issue would be resolved, with the original track being reinstated. The initial Kaws and Verdy physical versions of the album did not include either version of "So Be It" or Tyler, the Creator's appearance on "P.O.V.".
Large aromatic residues (tyrosine, phenylalanine, tryptophan) and β-branched amino acids (threonine, valine, isoleucine) are favored to be found in β-strands in the middle of β-sheets. Different types of residues (such as proline) are likely to be found in the edge strands in β-sheets, presumably to avoid the "edge-to-edge" association between proteins that might lead to aggregation and amyloid formation. A very simple structural motif involving β-strands is the β-hairpin, in which two antiparallel strands are linked by a short loop of two to five residues, of which one is frequently a glycine or a proline, both of which can assume the dihedral-angle conformations required for a tight turn or a β-bulge loop. Individual strands can also be linked in more elaborate ways with longer loops that may contain α-helices.
Norethisterone acetate (NETA), also known as norethindrone acetate and sold under the brand name Primolut-Nor among others, is a progestin medication which is used in birth control pills, menopausal hormone therapy, and for the treatment of gynecological disorders. The medication is available in low-dose and high-dose formulations and is used alone or in combination with an estrogen. It is ingested orally. Side effects of NETA include menstrual irregularities, headaches, nausea, breast tenderness, mood changes, acne, increased hair growth, and others. NETA is a progestin, or a synthetic progestogen, and hence is an agonist of the progesterone receptor, the biological target of progestogens like progesterone. It has weak androgenic and estrogenic activity and no other important hormonal activity. The medication is a prodrug of norethisterone in the body. NETA was patented in 1957 and was introduced for medical use in 1964. It is sometimes referred to as a "first-generation" progestin. NETA is marketed widely throughout the world. It is available as a generic medication.
Sources: en.wikipedia.org
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.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.