The short version of Melanocortin receptor fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-05-01. Anything still debated is marked as such rather than presented as settled.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide (ACTH fragment analog) | Not a steroid; does not belong to the melanocortin agonist drugs by marketing category |
| Molecular formula | C37H51N9O10S (commonly cited) | Reported values vary slightly with salt and counter-ion content |
| Appearance | White to off-white lyophilized powder | A single batch may appear as a loose cake or fluffy solid |
| Solubility | Freely soluble in water and aqueous buffer | Stock solutions are usually prepared in sterile water or saline |
| Typical storage | −20 °C or below, desiccated and protected from light | Seal opened vials promptly to limit moisture uptake |
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
The consensus view in contemporary palaeontology is that the flying theropods, or avialans, are the closest relatives of the deinonychosaurs, which include dromaeosaurids and troodontids. Together, these form a group called Paraves. Some basal members of Deinonychosauria, such as Microraptor, have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small. This evidence raises the possibility that the ancestor of all paravians may have been arboreal, have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, studies suggest that the first avialans were omnivores. The Late Jurassic Archaeopteryx is well known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to display both clearly traditional reptilian characteristics—teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor.
When Noriega created the PDF in 1983, he brought into its control Panama's customs and immigration apparatus, as well as the country's whole transportation network. This expansion of the military's role occurred simultaneously with a large growth in the cocaine trade, as well as in markets for weapons in various military conflicts in Central America. The profits the military reaped from these activities gave Noriega's military regime considerable financial clout. Noriega took control of most major newspapers by either buying a controlling stake in them or forcing them to shut down. The government also harassed, intimidated, or exiled individual journalists and editors. The newspaper La Prensa, which remained independent and was frequently critical of Noriega, had its staff intimidated and its offices damaged; eventually, it too was forced to close. In May 1984, Noriega allowed the first presidential elections in 16 years. Noriega and Díaz Herrera picked Nicolás Ardito Barletta Vallarino to be the PRD's candidate, with the intention of keeping him under close control. When the initial results showed Arias, who had the support of much of the opposition, on his way to a landslide victory, Noriega halted the count. After brazenly manipulating the results, the government announced that Barletta had won by a slim margin of 1,713 votes. Independent estimates suggested that Arias would have won by as many as 50,000 votes had the election been conducted fairly. More than 60,000 votes were not included in the final count.
== External links == Sophora flavescens Ait. Ya Ling, Jian; Ying Zhang, Guo; Jie Cui, Zhao; Kai Zhang, Chang (2007). "Supercritical fluid extraction of quinolizidine alkaloids from Sophora flavescens Ait. and purification by high-speed counter-current chromatography" (PDF). Journal of Chromatography A. 1145 (1–2): 123–127. doi:10.1016/j.chroma.2007.01.080. PMID 17289059. Krishna, Panthati Murali; Knv, Rao; S, Sandhya; Banji, David (2012). "A review on phytochemical, ethnomedical and pharmacological studies on genus Sophora, Fabaceae". Revista Brasileira de Farmacognosia. 22 (5): 1145–1154. doi:10.1590/S0102-695X2012005000043.
cooperativity Also cooperative binding. A phenomenon observed in some enzymes, receptor proteins, and protein complexes which have multiple binding sites, whereby the binding of a ligand to one or more sites apparently increases or decreases the affinity of one or more other binding sites for other ligands. This concept highlights the sensitive nature of the chemistry that governs interactions between biomolecules: the strength and specificity of interactions between protein and ligand are influenced, sometimes substantially, by nearby interactions (often conformational changes) and by the local chemical environment in general. Cooperativity is frequently invoked to account for the non-linearity of data resulting from attempts to measure the association/dissociation constants of particular protein–protein interactions.
In May 2014, researchers announced that they had successfully introduced two new artificial nucleotides into bacterial DNA, alongside the four naturally occurring nucleotides, and by including individual artificial nucleotides in the culture media, were able to passage the bacteria 24 times; they did not create mRNA or proteins able to use the artificial nucleotides.
Sources: en.wikipedia.org
== Poiseuille's equation for an ideal isothermal gas == For a compressible fluid in a tube the volumetric flow rate Q(x) and the axial velocity are not constant along the tube; but the mass flow rate is constant along the tube length. The volumetric flow rate is usually expressed at the outlet pressure. As fluid is compressed or expanded, work is done and the fluid is heated or cooled. This means that the flow rate depends on the heat transfer to and from the fluid. For an ideal gas in the isothermal case, where the temperature of the fluid is permitted to equilibrate with its surroundings, an approximate relation for the pressure drop can be derived. Using ideal gas equation of state for constant temperature process (i.e.,
=== Hydrates and aqueous solution === The hexahydrate Dy(ClO4)3·6H2O is a commonly used crystalline form. In dilute aqueous solution, Dy3+ is strongly hydrated, while perchlorate behaves mainly as a weakly coordinating counterion. Raman-spectroscopic studies of aqueous dysprosium perchlorate solutions support an inner hydration shell containing approximately eight to nine water molecules around Dy3+, with increasing ion pairing only at higher concentrations. Thermodynamic measurements of aqueous rare-earth perchlorates likewise show that dysprosium perchlorate behaves as a strongly hydrated electrolyte, with non-ideal solution behavior arising from both hydration and ionic association.
21CFR50.3: Code of Federal Regulations, Title 21--Food and Drugs, Chapter I--Food and Drug Administration, Department of Health and Human Services, Part 50--Protection of Human Subjects, Subpart A--General Provisions, Sec. 50.3 Definitions 21CFR312.3: Code of Federal Regulations, Title 21--Food and Drugs, Chapter I--Food and Drug Administration, Department of Health and Human Services, Part 312--Investigational New Drug Application, Subpart A--General Provisions, Sec. 312.3 Definitions and Interpretations, archived from the original on June 26, 2003 ICH E6: Guidance for Industry - E6 Good Clinical Practice: Consolidated Guidance (PDF), U.S. Department of Health and Human Services, Food and Drug Administration, April 1996, archived from the original (PDF) on July 9, 2009 ICH E9: Guidance for Industry - E9 Statistical Principles for Clinical Trials (PDF), U.S. Department of Health and Human Services, Food and Drug Administration, September 1998, archived from the original (PDF) on July 10, 2009 NCI: Dictionary of Cancer Terms, National Cancer Institute, archived from the original on 2008-10-25, retrieved 2008-10-05 NLM: Glossary of Clinical Trials Terms, U.S. National Library of Medicine, archived from the original on 2011-09-02, retrieved 2008-10-05
The myosin-binding protein C, cardiac-type is a protein that in humans is encoded by the MYBPC3 gene. This isoform is expressed exclusively in heart muscle during human and mouse development, and is distinct from those expressed in slow skeletal muscle (MYBPC1) and fast skeletal muscle (MYBPC2).
Sources: en.wikipedia.org
Furthermore, a study examining 20 different human tumors uncovered a recurrent mutation in ANKRD26 that adversely affects the interaction between ANKRD26 and PIDD1 with centrosomes, thereby increasing the survival of cells with more than required number of centrosomes. The process of centrosome accumulation initiates a signaling pathway characterized by the involvement of Caspase-2 and the PIDDosome, which collectively contribute to the stabilization of p53 and the induction of p21 expression. This series of events can lead to an increase in PIDD1 levels over time, as it is also a downstream target of p53. The observed rise in PIDD1 expression is likely a result of subsequent DNA damage occurring in cells that fail to effectively arrest their cell cycle in the presence of excess centrosomes. Consequently, this situation may activate p53 through either the conventional DNA damage response mechanism or as a result of delayed M-phase progression caused by complications in chromosome alignment. This mechanism guarantees the effective operation of the p21 checkpoint, which, in turn, promotes the viability of aneuploid cells. At the same time, a lack of CASP2 intensifies tumor advancement in this cancer model following treatment with cisplatin, leading to an accelerated progression of the malignancy. PIDDosome-deficient animals provide an intriguing model for exploring the effects of ploidy on liver function and regenerative processes, avoiding the complications that arise from a global deficiency of p53.
== Leslie Ettre Award == In 2008, the Leslie Ettre Award of the International Symposium on Capillary Chromatography was established by the PerkinElmer Corporation. The award is given each year to a scientist, 35 years old or younger, for the most interesting original research in capillary gas chromatography in environmental and food safety.
Druze tradition honors several "mentors" and "prophets", and Elijah (Khidr) is honored as a prophet. Druze venerate Elijah, and he is considered a central figure in Druzism. And due to his importance in Druzism, the settlement of Druze on Mount Carmel had partly to do with Elijah's story and devotion. There are two large Druze towns on the eastern slopes of Mount Carmel: Daliyat al-Karmel and Isfiya. The Druze regard the Cave of Elijah as holy, and identify Elijah as "El-Khidr", the green prophet who symbolizes water and life, a miracle who cures the sick.
Sources: en.wikipedia.org
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.
It was developed in the Soviet Union during the early 1980s by groups at the Institute of Molecular Genetics in Moscow. Russian approval for intranasal use followed, and it has been marketed there since. Western laboratories encountered it mainly through translated literature and, later, through online research-chemical trade.
It holds a Russian registration as a prescription nasal product but has no approval from the European Medicines Agency or the United States Food and Drug Administration. Buyers outside Russia usually receive material sold strictly for laboratory research. That distinction matters because research-grade and pharmaceutical-grade products carry different documentation and testing expectations.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.