This is a working overview of melanocortin signalling, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-31 and is reviewed periodically as new material appears.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | ≥ 95 % of peak area by HPLC | Some suppliers quote 98 % or higher |
| Identity confirmation | Mass spectrometry (electrospray or MALDI) | Observed mass is compared with the calculated mass |
| Common analytical method | Reversed-phase HPLC on a C18 column | Acetonitrile and water gradients with trifluoroacetic acid |
| Primary degradation route | Oxidation of the methionine residue | Yields a sulfoxide that separates cleanly on chromatography |
| Storage of dissolved material | Aliquoted and frozen at −20 °C or below | Single-use aliquots avoid repeated temperature cycling |
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
After death, a body will decay. Burial is not necessarily a public health requirement. Contrary to conventional wisdom, the World Health Organization advises that only corpses carrying an infectious disease strictly require burial. Human burial practices are the manifestation of the human desire to demonstrate "respect for the dead". Cultures vary in their mode of respect. Some reasons follow:
have also presented a TFO targeting the promoter sequence of bcl-2, a gene inhibiting apoptosis. The observed inhibition of transcription can also have negative health effects like its role in the recessive, autosomal gene for Friedreich's Ataxia. In Fredrick's Ataxia, triplex DNA formation impairs the expression of intron 1 of the FXN gene. This results in the degeneration of the nervous system and spinal cord, impairing the movement of the limbs. To combat this triplex instability, nucleotide excision repair proteins (NERs) have been shown to recognize and repair triple-stranded DNA structures, reinstating full availability of the previously inhibited and unstable gene.
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Sources: en.wikipedia.org
In 1801, the civil parishes that form the modern borough had a total population of 2,022. This rose slowly throughout the nineteenth century, as the district became built up; reaching 5,646 in the middle of the century. When the railways arrived the rate of population growth increased. The population took five decades to rebound to the more muted peak of the 1950s, when much industry relocated from London, further boosting the speed of the wave of new housing then built. Brent is the most diverse locality in the UK by country of birth. It in 2019 became the only local authority with over 50% of residents, namely 52%, born abroad. Large Asian and Indian, Black African, Black Caribbean, Irish, and Eastern European communities exist. 45 per cent of the population was a minority ethnicity in the 1991 census, the most in England at the time. In 1991 17.2% were Indian, 10.2% were Black Caribbean and 9% were Irish. Brent was the only Outer London borough combining high proportions of Indian and Afro-Caribbean ethnicities. The 2001 UK Census found that the borough had a population of 263,464 residents, of whom 127,806 were male, and 135,658 female. Of those stating a choice, 47.71% described themselves as Christian, 17.71% as Hindus, 12.26% as Muslims and 10% as having no religion. Among residents, 39.96% were in full-time employment and 7.86% in part-time employment – compared to a London average of 42.64% and 8.62%, respectively.
=== Violence towards voters === On October 30, 2024, an 18-year-old man in Jacksonville, Florida, was arrested for aggravated assault and improper exhibition of a dangerous weapon after brandishing a machete at two women outside an early voting center. He, along with seven other teenagers, allegedly approached and antagonized members of the opposing political party as they were demonstrating. Neither the teenager's nor the women's political parties were disclosed, although later posts by the Duval Democratic Party described the teenager's party as a "group of young men carrying Trump flags". On November 1, 2024, a voter wearing a "Let's Go Brandon" hat was reportedly struck by a poll worker after a verbal altercation over his hat at an Orangeburg County, South Carolina, polling location. Also on November 1, a man in Bath, New York, was arrested for assaulting someone in a supermarket for wearing a Trump hat.
The March of the Chinese People's Liberation Army was adopted as the military anthem by the Central Military Commission on 25 July 1988. The lyrics of the anthem were written by composer Gong Mu (real name: Zhang Yongnian; Chinese: 张永年) and the music was composed by Korea-born Chinese composer Zheng Lücheng.
== Reproduction and life cycle == Most Hydras can reproduce sexually under certain conditions, though they typically choose to reproduce asexually instead. Unlike many members of the Hydrozoa, which alternate between the polyp form and the medusa form (the life stage where sexual reproduction occurs), Hydra never progress beyond the polyp phase in their life cycle. Instead, when food is plentiful, many Hydra opt to reproduce asexually by budding. A section of the body wall and an extension of the digestive cavity develop, creating a bud. The buds grow into miniature adults and break away when mature. When a Hydra is well fed, a new bud can form every two days. When conditions are harsh, often before winter or in poor feeding conditions, sexual reproduction then occurs in some Hydra. Either the ovaries or testes develop from interstitial cells of the epidermis, resulting in swellings in the body wall. The testes release free-swimming gametes into the water, and these can fertilize the egg in the ovary of another individual. The fertilized eggs secrete a tough outer coating, and, as the adult dies (due to starvation or cold), these resting eggs fall to the bottom of the lake or pond to await better conditions, whereupon they hatch into nymph Hydra. The male Hydra is typically smaller in size and bears 1 to 8 conical testes, while the female is larger and has 1 to 2 ovaries. Some Hydra species, like Hydra circumcincta and Hydra viridissima, are hermaphrodites and may produce both testes and ovaries at the same time.
Sources: en.wikipedia.org
The state prosecuted the accused as Marxist revolutionaries seeking to establish a Soviet-backed regime in South West Africa. In what became known as the "1967 Terrorist Trial", six of the accused were found guilty of committing violence in the act of insurrection, with the remainder convicted for armed intimidation, or having received military training for the purpose of insurrection. During the trial, the defendants unsuccessfully argued against allegations that they were privy to an external communist plot. All but three received sentences ranging from five years to life imprisonment on Robben Island.
== Structural studies == As of late 2007, 8 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1A0G, PDB: 1DAA, PDB: 1G2W, PDB: 2DAA, PDB: 2DAB, PDB: 3DAA, PDB: 4DAA, and PDB: 5DAA.
In May 2024, Cerebras in collaboration with researchers from Sandia National Laboratories, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, and the National Nuclear Security Administration, simulated 800,000 atoms interacting with each other, calculating the interactions in increments of one femtosecond at a time. Each step took just microseconds to compute on the Cerebras WSE-2, much faster than on the Frontier supercomputer. Cerebras was named to the "100 Most Influential Companies list" by Time in May 2024. In June 2024, Cerebras announced a collaboration with Dell Technologies, for AI compute infrastructure for generative AI. In August 2024, Cerebras launched its AI inference service, which it claimed to be ten to twenty times faster than systems built using Nvidia's H100 Hopper graphics processing units. In January 2025, the Mayo Clinic announced a collaboration with Cerebras to combine genomic data with de-identified data from patient records and medical evidence to explore the ability to predict a patient's response to treatments to manage disease. In January 2025, Cerebras announced support for DeepSeek's R1 70B reasoning model at 1,600 tokens/second. In February 2025, Mistral AI began using Cerebras products to power its Le Chat service and reached a speed record. Also in February 2025, Cerebras announced a partnership with Perplexity AI's Sonar model, which runs on Cerebras chips at 1,200 tokens per second.
Sources: en.wikipedia.org
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.
The methionine residue at the start of the chain is vulnerable to oxidation, producing a sulfoxide variant. Amide bonds can also hydrolyze, though more slowly under neutral conditions. Cold storage, oxygen exclusion and minimization of freeze-thaw cycles slow both processes but do not stop them.
A purity number on a certificate does not establish that a powder is the same product as a registered nasal medicine. Counter-ion content, residual solvents and peptide-related impurities may differ between the two. Independent verification is the only way to narrow that gap.
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.