The short version of peptide purity fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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 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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
| 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 |
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
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.
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.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
== Cell function and characteristics == Unlike other fibroblast cell types, dermal fibroblasts are far less likely to change into other cell types. For example, when a dermal fibroblast and a corneal fibroblasts are placed in the same concentrations of fibroblast growth factor, dermal fibroblast will not differentiate or change. As noted by Dr. J. Lewis and Dr. A. Johnson authors of Microbiology of the Cell, "fibroblasts from the skin are different" and behave differently from other fibroblast cells to identical chemical stimuli. Furthermore, dermal fibroblasts are less likely to replicate in either in vivo and in vitro environments than are other fibroblast types. Dermal fibroblasts require far higher concentrations of fibroblast growth factor (FGF) in order to undergo cell replication. Dermal fibroblasts are responsible for creating the ECM which organizes the stratified squamous epithelial cells of the epidermis into a unified tissue. Furthermore, dermal fibroblasts create long fibrous bands of connective tissue which anchor the skin to the fascia of the body. Therefore, without dermal fibroblasts, the largest and heaviest organ would not tightly adhere to body's frame.
== Awards and honours == 2007: Foreign associate of the National Academy of Sciences of the United States 2007: Robert Koch Gold Medal 1998: Fellow of the Academy of Medical Sciences (FMedSci). 1973: Elected Fellow of the Royal Society
A cigarette is a thin cylinder of tobacco rolled in thin paper for smoking. The cigarette is ignited at one end, causing it to smolder, and the resulting smoke is orally inhaled via the opposite end. Cigarette smoking is the most common method of tobacco consumption. The term cigarette usually refers to a tobacco cigarette, but the word is sometimes used to refer to other substances, such as a cannabis cigarette or a herbal cigarette. A cigarette is distinguished from a cigar by its usually smaller size, use of processed leaf, different smoking method, and paper wrapping, which is typically white.
The USDA removed the table showing the Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods Release 2 (2010) table due to the lack of evidence that the antioxidant level present in a food translated into a related antioxidant effect in the body.
However, β-strands are rarely perfectly extended; rather, they exhibit a twist. The energetically preferred dihedral angles near (φ, ψ) = (–135°, 135°) (broadly, the upper left region of the Ramachandran plot) diverge significantly from the fully extended conformation (φ, ψ) = (–180°, 180°). The twist is often associated with alternating fluctuations in the dihedral angles to prevent the individual β-strands in a larger sheet from splaying apart. A good example of a strongly twisted β-hairpin can be seen in the protein BPTI. The side chains point outwards from the folds of the pleats, roughly perpendicularly to the plane of the sheet; successive amino acid residues point outwards on alternating faces of the sheet.
Sources: en.wikipedia.org
== Treatment == Immunosuppressive treatment is the gold standard management in order to achieve remission of the blood vessel inflammation that occurs in active microscopic polyangiitis. The current immunosuppressive protocols consists of a combination of high dose of glucocorticoids in combination with either cyclophosphamide or Rituximab. In cases of life threatening disease treatment with plasmapheresis can also be applied. The immunosuppressive treatment is slowly tapered down under a period of several months but there is at the moment no consensus about the total duration of the therapy. Discontinuation of immunosuppression can be related to increased risk for disease flares.
== External links == Galerie Loevenbruck (Levé's artistic representation): Photographs Archived 2 October 2011 at the Wayback Machine, biography Archived 2 October 2011 at the Wayback Machine, books Archived 2 October 2011 at the Wayback Machine, reviews and press Editions P.O.L. (Levé's publisher), including a video of the author reading from Œuvres Short essay on Levé's aesthetics, focusing particularly on Works Archived 13 August 2015 at the Wayback Machine Written works online: Excerpt from Lorin Stein's English translation of Autoportrait (Paris Review) Photo series Amérique Obituary notices: Libération, by Philippe Lançon, 17 October 2007; by Jacques Morice, Télérama, 22 October 2007 Adaptations/homages by other artists: Autoportrait(s) Archived 28 August 2012 at the Wayback Machine, an online graphic design tribute to Levé (Grand Prix ETPA 2010) by Anne Gardes; CQPVD, ou Ce que parler veut dire Archived 22 October 2013 at the Wayback Machine, a 2008 theatrical work by Jade Duviquet, adapted in part from Levé's Autoportrait
The colour-fast (non-fading) dye was an item of luxury trade, prized by Romans, who used it to colour ceremonial robes. Used as a dye, the colour shifts from blue (peak absorption at 590 nm, which is yellow-orange) to reddish-purple (peak absorption at 520 nm, which is green). It is believed that the intensity of the purple hue improved rather than faded as the dyed cloth aged. Vitruvius mentions the production of Tyrian purple from shellfish. In his History of Animals, Aristotle described the shellfish from which Tyrian purple was obtained and the process of extracting the tissue that produced the dye. Pliny the Elder described the production of Tyrian purple in his Natural History:
Each single-use vial of reslizumab is formulated as 10 mg/mL reslizumab in an aqueous solution containing 2.45 mg/mL sodium acetate trihydrate, 0.12 mg/mL glacial acetic acid, and 70 mg/mL sucrose, with a pH of 5.5.
=== Missing and identification === According to UNICEF, the standard system for identifying, documenting, tracing and reuniting children with relatives or siblings was barely functional in early December 2023. Additional difficulties arose from the intensity of the fighting and the rapidly changing conditions in Gaza, which hindered efforts to communicate with hospitals and medical staff. Four months into the conflict, the UN estimated that about 40% of all people in Gaza had lost identification cards and documents due to the war, making it more difficult to identify unaccompanied children and reunite them with their families. Humanitarian organizations also reported difficulties with orphaned children who were too young to know their own names. A UNICEF spokesman said: "The youngest ones very often cannot say their name and even the older ones are usually in shock so it can be extremely difficult to identify them". Hospital and emergency workers in Gaza noted that parents and relatives of some children wrote on children's bodies, mostly on their legs and abdomens, so the children would be identifiable if found in the rubble or get lost. One employee stated: "Many of the children are missing, many get here with their skulls broken… and it’s impossible to identify them, only through that writing do they get identified." In June 2024, Save the Children stated approximately 21,000 children were missing in Gaza, including 4,000 children believed to be buried under rubble. The bodies of some of these children remained unrecovered.
Sources: en.wikipedia.org
=== Molecular basis === Research has shown that there are more than 35 specific genetic disorders associated with arthrogryposis. Most of those mutations are missense, which means the mutation results in a different amino acid. Other mutations that could cause arthrogryposis are: single gene defects (X-linked recessive, autosomal recessive and autosomal dominant), mitochondrial defects and chromosomal disorders (for example: trisomy 18). This is mostly seen in distal arthrogryposis. Mutations in at least five genes (TNN12, TNNT3, TPM2, MYH3 and MYH8) could cause distal arthrogryposis. There could be also connective tissue, neurological or muscle development disorders.
Surgery to attempt tumour removal is usually not possible or advisable for DIPG. By nature, these tumors invade diffusely throughout the brain stem, growing between normal nerve cells. Aggressive surgery would cause severe damage to neural structures vital for arm and leg movement, eye movement, swallowing, breathing, and even consciousness. A surgically performed brainstem biopsy for immunotyping of diffuse intrinsic pontine glioma has served a limited role in experimental clinical studies and treatment trials. However, recent studies have shown stereotactic needle biopsies can commonly be done safely and resulted in a histological diagnosis in 96.8% of cases. This has increased the frequency that biopsies have been used for diagnosis. This, however, is not the current standard of care for all patients, as it presents considerable risk depending on the biopsy location. The decision to do a biopsy is generally only done when medical imaging appears atypical enough that a different diagnosis is possible. Pontine biopsy is in no way a therapeutic or curative surgery, and the risks (potentially catastrophic and fatal) are only outweighed when the diagnosis is uncertain or the patient is enrolled in an approved clinical trial.
==== Authority to canonize ==== For several centuries, the bishops, or in some places only the primates and patriarchs, could grant martyrs and confessors public ecclesiastical honour; such honour, however, was always decreed only for the local territory of which the grantors had jurisdiction. Universal acceptance of the cultus was said to be made possible by the pope because he claimed to be the sole ruler the universal Catholic Church. Toward the end of the eleventh century the popes judged it necessary to restrict episcopal authority in this regard, and therefore decreed that the virtues and miracles of persons proposed for public veneration should be examined in councils, more specifically in general councils. Popes Urban II, Calixtus II, and Eugene III conformed to this discipline. It happened, even after these decrees, that "some, following the ways of the pagans and deceived by the fraud of the evil one, venerated as a saint a man who had been killed while intoxicated." Pope Alexander III (1159–81) prohibited his veneration in these words: "For the future you will not presume to pay him reverence, as, even though miracles were worked through him, it would not allow you to revere him as a saint unless with the authority of the Roman Church." Theologians disagree as to the full import of this decretal: either a new law was instituted, in which case the Pope then for the first time reserved the right of beatification to himself, or an existing law was confirmed.
Certain atomic nuclei are able to absorb radio frequency (RF) energy when placed in an external magnetic field; the resultant evolving spin polarization can induce an RF signal in a radio frequency coil and thereby be detected. In other words, the nuclear magnetic spin of protons in the hydrogen nuclei resonates with the RF incident waves and emit coherent radiation with compact direction, energy (frequency) and phase. This coherent amplified radiation is then detected by RF antennas close to the subject being examined. It is a process similar to masers. In clinical and research MRI, hydrogen atoms are most often used to generate a macroscopic polarized radiation that is detected by the antennas. Hydrogen atoms are naturally abundant in humans and other biological organisms, particularly in water and fat. For this reason, most MRI scans essentially map the location of water and fat in the body. Pulses of radio waves excite the nuclear spin energy transition, and magnetic field gradients localize the polarization in space. By varying the parameters of the pulse sequence, different contrasts may be generated between tissues based on the relaxation properties of the hydrogen atoms therein. Since its development in the 1970s and 1980s, MRI has proven to be a versatile imaging technique. While MRI is most prominently used in diagnostic medicine and biomedical research, it also may be used to form images of non-living objects, such as mummies.
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.
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.