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.
Last reviewed on 2026-04-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
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.
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.
Thanks to the protective function of radioprotectors, the dose of radiation used to treat malignant tumors (cancer) can be increased, thereby increasing the effectiveness of the therapy. There are also radiosensitizers, which increase the sensitivity of malignant tumor cells to ionizing radiation. As early as 1921, the German radiologist Hermann Holthusen (1886-1971) described that oxygen increases the sensitivity of cells.
=== Positioning, latch and breast milk drainage === Clinically, proper positioning and latch of infants to the nipple can resolve persistent nipple pain brought by inefficient milk flow and tongue-tie, avoid nipple trauma and fissure, prevent breast mastitis and allow efficient wound healing. Mothers can place the nipple asymmetrically in the top half of the infant's mouth. On the other hand, the continuation of effective and frequent breast milk drainage, especially draining the first milk production after childbirth called colostrum, can prevent the development of mastitis and engorgement. Common practices include manual expression, pumping and pressure-relief of the areola. Tools such as effective breast pumps and lubricants can be used to achieve the goal of successful draining and prevent the blockage of milk ducts. In addition, moderating the oversupply and the rapid flow of breast milk can effectively ameliorate painful feelings. If the pain is so severe that the drainage cannot be carried out, painkillers such as ibuprofen can be taken to minimize nipple ache for successful lactation.
Musicians of these decades, especially in jazz and folk music, were influenced by the shadow of nuclear war. Probably the most famous, passionate and influential of all was Bob Dylan, notably in his songs "Masters of War" and "A Hard Rain's a-Gonna Fall" (written just before the Cuban Missile Crisis). In 1965 Barry McGuire's version of P. F. Sloan's apocalyptic "Eve of Destruction" was a number one hit in the United States and elsewhere. Van Cliburn was a pianist who was celebrated with a ticker tape parade after winning a musical competition in the Soviet Union. From 1956 through the late 1970s, the US State Department sent its finest jazz musicians to show off music that appealed to youth, to demonstrate racial harmony at home, and to undergird freedom as jazz was a democratic music form, free flowing and improvised. Jazz tours of the Soviet Union were organized in 1956, and lasted through the 1970s. In addition to jazz, the US State Department also supported the performance of classical music by noteworthy American orchestras and soloists as part of its cultural diplomacy initiatives during the Cold War. During the 1950s, the bass-baritone William Warfield was recruited by the Department of State to perform in six separate European tours which featured productions of the opera Porgy and Bess . In 1961-1962 Howard Hanson's Eastman Philharmonia Orchestra at the Eastman School of Music was selected to represent the nation on an international concert tour which included thirty four cities and sixteen countries in Europe, the Middle East and Russia.
Field rations can be eaten at any temperature, but are preferably heated or cooked. However, as the use of cooking appliances or fire may be unavailable or tactically unwise, smokeless solid fuel and a portable stove are typically included in rations to heat meals. Hexamine fuel tablets have traditionally been preferred, though gelatinized ethanol is also sometimes used. Some modern field rations use a flameless ration heater instead of fuel tablets. NATO standardization states that, while main courses and entrées must be consumable without heating, main course components and hot beverages should be provided with a heater, with such items intended to be heated to a minimum temperature of 62 °C from an ambient temperature of 20 °C within 12 minutes.
Sources: en.wikipedia.org
== Lateral and mid support structures == The midsection of the vagina is supported by its lateral attachments to the arcus tendineus. Some describe the pubocervical fascia as extending from the pubic symphysis to the anterior vaginal wall and cervix. Anatomists do not agree on its existence.
== Prognosis == Twenty-five percent of psychiatric patients with catatonia will have more than one episode throughout their lives. Treatment response for patients with catatonia is 50–70%, with treatment failure being associated with a poor prognosis. Many of these patients will require long-term and continuous mental health care. The prognosis for people with catatonia due to schizophrenia is much worse compared to other causes. In cases of malignant catatonia, the mortality rate is as high as 20%.
== Critical analysis == In Posthumanism in the Novels of Kurt Vonnegut, ice-nine is described as an example of a wampeter in the fictional Bokononism religion, the pivot around which a karass, or a group of randomly interrelated people, revolves. Calling it both the cause of the apocalypse and one of the book's main sources of humor, the book argues that ice-nine sets the entire tone for the novel, which is "rendered inert" by its fragmentary structure and fundamental tension. The book also states that ice-nine reverses the normal hierarchy in which living organisms use water as a resource, becoming the "successor of organic life on planet Earth". Theoretical physicist and expert on string theory Leonard Susskind, in his book The Cosmic Landscape, calls Cat's Cradle and its use of ice-nine a "cautionary tale about madness and instability in a world full of nuclear weapons", as well as being based on the real scientific principle of metastability. Saying that: while in the real world liquid water at room temperature is stable, he explains that in Vonnegut's universe, normal water is only metastable, and since ice-nine is more stable than water, it will form naturally "sooner or later" even without the introduction of the seed crystal. It describes the fact that supercooled water takes on similar traits, and will completely freeze if a normal chunk of ice is introduced. The book also relates this to the metastability of vacuums in string theory and their ability to create a diverse universe. In Dr. Strangelove's America, Margot A.
Sources: en.wikipedia.org
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.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
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.