If you have been reading about mass spectrometry and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-09-08. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
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.
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.
On 1 June, Humboldt and his party arrived in Washington, which had become the United States capital in 1800. The city was still under construction, with fewer than 5,000 inhabitants and about 800 houses clustered around the Capitol, the President’s residence, and the Navy Yard along the Potomac River. The Executive Mansion, where Humboldt was invited to lunch with President Thomas Jefferson, was also incomplete and surrounded by unfinished grounds. Jefferson’s study, serving as his Cabinet room, was filled with a variety of personal and official items, including his books, maps, gardening tools, and a cage for his favorite mockingbird. It was in this space that Jefferson and Humboldt engaged in detailed discussions. Jefferson, at sixty-one, was known for his unpretentious lifestyle and devotion to family. The luncheon, attended by figures such as Charles Willson Peale, was informal, focusing on topics like natural history and international customs rather than politics. Jefferson and Humboldt quickly developed mutual respect, sharing scientific interests and political ideals. Jefferson was knowledgeable in various scientific fields, having conducted meteorological studies, experimented with agricultural techniques, and designed a plow. He was well-acquainted with the works of leading European scientists and demonstrated expertise in astronomy and paleontology. He offered Humboldt access to his Washington residence and invited him to visit Monticello in Virginia.
Driver, who is incarcerated at Salinas Valley State Prison (CDCR #D-35391), has filed numerous pro se civil rights actions under 42 U.S.C. § 1983 at multiple California facilities. While his lawsuits have consistently been dismissed on procedural grounds, he has appealed some decisions to the U.S. Court of Appeals for the Ninth Circuit. In May and June 2022, Adilah Patton, a 28‑year‑old pretrial detainee in Indianapolis, was forcibly injected twice with Invega Sustenna while in custody at the Marion County Adult Detention Center. A federal lawsuit filed on her behalf alleges that the injections were administered without a medical assessment, a prescription, or the consent of her court‑appointed guardian. The lawsuit describes the injections as assault, battery, excessive force, and violations of the Fourteenth Amendment right to informed consent. In September 2024, Haitian immigrant Cassandra Fameux filed a criminal complaint alleging that her husband, Michigan anesthesiologist Dr. Paul Gregory St. Claire, and psychiatrist Dr. Dominic Barberio forcibly injected her monthly from 2017 to 2021 with unprescribed Invega Sustenna—sometimes at doses up to 256 mg—as "punishment" when her husband was angry. Divorce court testimony and a recorded conversation indicate Barberio admitted she was not schizophrenic; two psychiatrists found she had PTSD, not bipolar disorder or schizophrenia. A subsequent police investigation led to a recommendation that her husband be charged with domestic assault.
=== 1950–1980: Pivot to pharmaceutical research and global expansion === Due to price declines for penicillin, Pfizer searched for new antibiotics with greater profit potential. Pfizer discovered oxytetracycline in 1950, and this changed the company from a manufacturer of fine chemicals to a research-based pharmaceutical company. Pfizer developed a drug discovery program focused on in vitro synthesis to augment its research in fermentation technology. In 1959, the company established an animal health division with a 700-acre (280 ha) farm and research facility in Terre Haute, Indiana. By the 1950s, Pfizer had established offices in Belgium, Brazil, Canada, Cuba, Mexico, Panama, Puerto Rico, and the United Kingdom. In 1960, the company moved its medical research laboratory operations out of New York City to a new facility in Groton, Connecticut. In 1980, Pfizer launched Feldene (piroxicam), a prescription anti-inflammatory medication that became Pfizer's first product to reach $1 billion in revenue. In 1965, John Powers, Jr. became chief executive officer (CEO) of the company, succeeding John McKeen. As the area surrounding its Brooklyn, NY plant fell into decline in the 1970s and 1980s, the company formed a public-private partnership with New York City that encompassed the construction of low- and middle-income housing, the refurbishment of apartment buildings for the homeless and the establishment of a charter school. In 1972, Edmund T. Pratt Jr. became CEO of the company, succeeding John Powers, Jr.
==== Alzheimer's disease ==== There is indirect evidence to suggest that system Xc- might be upregulated in Alzheimer's patients. It has been found in Alzheimer's patients that there is an increase in phosphorylation of the alpha subunit of eukaryotic initiation factor 2 and in expression of transcription factor 4, both of which increase system Xc- expression. It has also been shown that administration of N-acetylcysteine leads to a significant improvement in certain cognitive tasks for Alzheimer's patients.
Sources: en.wikipedia.org
Similarly, damaged RNAs released from UVB-exposed keratinocytes activate TLR3 on intact keratinocytes. TLR3 activation stimulates TNF-alpha and IL-6 production, which initiate the cutaneous inflammation associated with sunburn. S100 proteins: S100 is a multigenic family of calcium modulated proteins involved in intracellular and extracellular regulatory activities with a connection to cancer as well as tissue, particularly neuronal, injury. Their main function is the management of calcium storage and shuffling. Although they have various functions, including cell proliferation, differentiation, migration, and energy metabolism, they also act as DAMPs by interacting with their receptors (TLR2, TLR4, RAGE) after they are released from phagocytes. Mono- and polysaccharides: The ability of the immune system to recognize hyaluronan fragments is one example of how DAMPs can be made of sugars.
Alcohol interacts with cocaine in vivo to produce cocaethylene, another psychoactive substance which may be substantially more cardiotoxic than either cocaine or alcohol by themselves. In 2024, a systematic review of human studies concluded that, despite some inconsistencies in the findings, the co-use of cocaine and alcohol poses a significantly greater risk of cardiovascular fatalities compared to cocaine use alone. This elevated risk is largely attributed to the formation of cocaethylene, a unique and toxic metabolite produced only when both substances are consumed together. Cocaethylene is associated with an 18- to 25-fold increased risk of sudden death, as well as a higher incidence of myocardial injury and cardiac arrest, underscoring the serious health risks of simultaneous cocaine and alcohol use.
Higher magnetization Higher stability in acidic and basic solution as well as organic solvents Chemistry on the graphene surface via methods already known for carbon nanotubes Magnetic nanoparticals have also be coated with a molecularly imprinted polymer which adds a specific recognition element to the particles, enabling them to be used to specifically capture target molecules of interest.
Sources: en.wikipedia.org
=== Mutations === Cystinosis is presented in patients with a range of CTNS mutations; as of 2017, over 100 have been identified. The most common mutation is a 57,257 base pair deletion commonly referred to as the 57 kb deletion. This was formally known as the 65 kb deletion; a misnomer originating from early incorrect estimates. Other reported mutations include other deletions, missense mutations, and in-frame deletions and insertions. The type and extent of mutation determines the type and severity of cystinosis in the carrier. This is a result of the degree of transport inhibition caused by the misfolding of cystinosin. For example, mild cystinosis is typically associated with mutations that do not affect the amino acids in the transmembrane domains of cystinosin. In contrast, infantile nephropathic cystinosis, the most severe form of the disease, is most commonly associated with a total loss of activity. Gene deletion resulting in the absence of either of the sorting motifs results in the delocalization of cystinosin to the cellular plasma membrane.
=== Economics === Trastuzumab costs about US$70,000 for a full course of treatment. Australia has negotiated a lower price of A$50,000 per course of treatment. Since October 2006, trastuzumab has been made available for Australian women and men with early-stage breast cancer via the Pharmaceutical Benefits Scheme. This is estimated to cost the country over A$470 million for 4–5 years supply of the drug. Roche has agreed with Emcure in India to make an affordable version of this cancer drug available to the Indian market. Roche has changed the brand name of the drug and has re-introduced an affordable version of the same in the Indian market. The new drug named Herclon would cost approximately RS75,000 INR (US$ 870) in the Indian market. On 16 September 2014, Genentech notified hospitals in the United States that, as of October, trastuzumab could only be purchased through their selected specialty drugs distributors not through the usual general line wholesalers. By being forced to purchase through specialty pharmacies, hospitals lost rebates from the big wholesalers and the ability to negotiate cost-minus discounts with their wholesalers.
12 November 2013: Kamrul Hasan Abdul Quddus, a Bangladeshi who murdered his Indonesian girlfriend in 2007. He was initially found guilty of murder and sentenced to death in 2010, and had his appeal to the Court of Appeal dismissed in 2012. After changes to the law took effect in 2013, he applied for re-sentencing and was re-sentenced to life imprisonment and 10 strokes of the cane. He tried filing an appeal for a lighter sentence but was turned down by the Court of Appeal in 2014. 13 November 2013: Wang Wenfeng, a Chinese national who robbed and murdered a taxi driver in 2009, was initially convicted of murder and sentenced to death in 2011. He had also lost his appeal to the Court of Appeal in 2012. When changes to the law took effect in 2013, he applied for re-sentencing and was re-sentenced to life imprisonment and 24 strokes of the cane. The prosecution filed an appeal but withdrew it in 2015 in light of the outcome of the prosecution's appeal against Kho Jabing's life sentence. 20 May 2016: Kho Jabing, a Malaysian hanged for the 2008 robbery and murder of a construction worker. After changes to the law took effect in 2013, he applied for re-sentencing and was initially re-sentenced to life imprisonment and 24 strokes of the cane on 14 August 2013. However, after the prosecution appealed, he was sentenced to death again in a landmark ruling by a majority decision of 3–2 in the Court of Appeal and eventually hanged in the afternoon of the same day his final appeal was dismissed.
== Businesses and organizations == Korea Land and Housing Corporation, a South Korean state-owned housing company LabCorp (stock symbol LH), a clinical laboratory company Lernout & Hauspie, a former Belgium-based speech and language technology company Literary and Historical Society (University College Dublin) Lufthansa (IATA airline designator), large European airline
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.
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.