heptapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-10-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
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.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
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.
== Further reading == Picknett, Lynn and Prince, Clive: The Turin Shroud: In Whose Image?, Harper-Collins, 1994 ISBN 0-552-14782-6. Antonacci, Mark : The Resurrection of the Shroud, M. Evans & Co., New York 2000, ISBN 0-87131-890-3 Whiting, Brendan, The Shroud Story, Harbour Publishing, 2006, ISBN 0-646-45725-X Di Lazzaro, Paolo (ed.) : Proceedings of the International Workshop on the Scientific Approach to the Acheiropoietos Images, ENEA, 2010, ISBN 978-88-8286-232-9. Olmi, Massimo, Indagine sulla croce di Cristo, Torino 2015 ISBN 978-88-6737-040-5 Jackson, John, The Shroud of Turin. A Critical Summary of Observations, Data, and Hypotheses, CMJ Marian Publishers, 2017, ISBN 9780692885734. Cozzo, Paolo; Merlotti, Andrea' Nicolotti, The Shroud at Court. History, Usages, Places and Images of a Dynastic Relic. Leiden-Boston: E.J. Brill, 2019.
=== Former markets === Russia – Pizza Hut began operating in Russia in 1991, when food supplies dwindled during the 1991 Soviet coup d'état attempt, prompting Russian president Boris Yeltsin to call Pizza Hut deliveries. Pizza Hut suspended operations in response to the 2022 Russian invasion of Ukraine. Later some restaurants re-opened operations under rebranded new trademark PittsaN (ПиццаН). Panama – In 2022, the Pizza Hut chain ceased its operations in Panamanian lands after reporting economic losses. Argentina – Pizza Hut opened in Argentina in 1983; however, they withdrew some time later. They returned in the mid-1990s but withdrew again in 1998 due to poor sales success. It was announced that it will be brought back to the country in 2025, but the exact date has not been confirmed. Chile – In 2025, the Pizza Hut chain downsized its operations in Chile as one of its two franchising concerns, Food Delivery Brands (which also handled Telepizza), went bankrupt as a result of the economic crisis the country had faced in the past decade and increasing competition from rival chains such as Little Caesars and Papa John's.
One of the key scientific figures that attempted to highlight the promising aspects of genetic engineering was Joshua Lederberg, a Stanford professor and Nobel laureate. While in the 1960s "genetic engineering" described eugenics and work involving the manipulation of the human genome, Lederberg stressed research that would involve microbes instead. Lederberg emphasized the importance of focusing on curing living people. Lederberg's 1963 paper, "Biological Future of Man" suggested that, while molecular biology might one day make it possible to change the human genotype, "what we have overlooked is euphenics, the engineering of human development." Lederberg constructed the word "euphenics" to emphasize changing the phenotype after conception rather than the genotype which would affect future generations. With the discovery of recombinant DNA by Cohen and Boyer in 1973, the idea that genetic engineering would have major human and societal consequences was born. In July 1974, a group of eminent molecular biologists headed by Paul Berg wrote to Science suggesting that the consequences of this work were so potentially destructive that there should be a pause until its implications had been thought through. This suggestion was explored at a meeting in February 1975 at California's Monterey Peninsula, forever immortalized by the location, Asilomar.
==== Absorption and ingestion from water ==== The biological half-life of ingested radon ranges from 30 to 70 minutes, with 90% removal at 100 minutes. In 1999, the US National Research Council investigated the issue of radon in drinking water. The risk associated with ingestion was considered almost negligible. The World Health Organization (WHO) recommends a maximum water contamination level of 100 Bq/L, while the US Environmental Protection Agency recommends a maximum of 11.1 Bq/L. The WHO also advises a maximum annual dose of 1 mSv−1 induced by radon from drinking water. Water from underground sources may contain significant amounts of radon depending on the surrounding rock and soil conditions, whereas surface sources generally do not. Radon is also released from water when temperature is increased, pressure is decreased and when water is aerated. Optimum conditions for radon release and exposure in domestic living from water occurred during showering. Water with a radon concentration of 104 pCi/L can increase the indoor airborne radon concentration by 1 pCi/L under normal conditions. However, the concentration of radon released from contaminated groundwater to the air has been measured at 5 orders of magnitude less than the original concentration in water. Ocean surface concentrations of radon exchange within the atmosphere, causing 222Rn to increase through the air-sea interface. Although areas tested were very shallow, additional measurements in a wide variety of coastal regimes should help define the nature of 222Rn observed.
==== Implications for cardiovascular disease and therapeutics ==== The dual extracellular and intracellular actions of PTHrP make it a promising target for cardiovascular therapies. Given its role in regulating cardiac cell growth and vascular integrity, modulating PTHrP expression or its intracellular signaling pathways could be beneficial in conditions such as heart failure, atherosclerosis, and ischemic heart disease. Additionally, therapeutic strategies that enhance intracrine PTHrP activity could improve angiogenesis and myocardial repair following injury. In conclusion, PTHrP is a key intracrine regulator in the cardiovascular system, influencing both myocardial and vascular function. Its ability to act within the nucleus and cytoplasm of cardiac cells highlights its potential as a therapeutic target for cardiovascular diseases. Future research focusing on the intracrine mechanisms of PTHrP may provide novel insights into cardiac regeneration and vascular remodeling.
Sources: en.wikipedia.org
=== Prime Ministers === Prime Minister for Bosnia and Herzegovina (part of Yugoslav Government) Rodoljub Čolaković (7 March 1945 – 27 April 1945) Prime Ministers Rodoljub Čolaković (27 April 1945 – September 1948) Đuro Pucar (September 1948 – March 1953) Chairmen of the Executive Council Đuro Pucar (March 1953 – December 1953) Avdo Humo (December 1953 – 1956) Osman Karabegović (1956–1963) Hasan Brkić (1963–1965) Rudi Kolak (1965–1967) Branko Mikulić (1967–1969) Dragutin Kosovac (1969 – April 1974) Milanko Renovica (April 1974 – 28 April 1982) Seid Maglajlija (28 April 1982 – 28 April 1984) Gojko Ubiparip (28 April 1984 – April 1986) Josip Lovrenović (April 1986 – April 1988) Marko Ceranić (April 1988 – 20 December 1990) Jure Pelivan (20 December 1990 – 8 April 1992)
== Occurrence == Pyrite is the most common of sulfide minerals and is widespread in igneous, metamorphic, and sedimentary rocks. It is a common accessory mineral in igneous rocks, where it also occasionally occurs as larger masses arising from an immiscible sulfide phase in the original magma. It is found in metamorphic rocks as a product of contact metamorphism. It also forms as a high-temperature hydrothermal mineral, though it occasionally forms at lower temperatures. Pyrite occurs both as a primary mineral, present in the original sediments, and as a secondary mineral, deposited during diagenesis. Pyrite and marcasite commonly occur as replacement pseudomorphs after fossils in black shale and other sedimentary rocks formed under reducing environmental conditions. Pyrite is common as an accessory mineral in shale, where it is formed by precipitation from anoxic seawater, and coal beds often contain significant pyrite. Notable deposits are found as lenticular masses in Virginia, U.S., and in smaller quantities in many other locations. Large deposits are mined at Rio Tinto in Spain and elsewhere in the Iberian Peninsula.
This description highlights the partial double bond that exists between the carbonyl carbon and nitrogen, which raises the rotational barrier. Thus, the molecule is not able to freely rotate around its main axis and the (E)-configuration is preferred due to steric repulsion of the larger substituents. This molecule has been tentatively identified in interstellar space by the ALMA radio telescope. It may have formed on dust grains. This could prove to be a key molecule for interstellar pre-biotic chemistry due to its peptide bond.
== Limitations == One major limitation of PCR is that prior information about the target sequence is necessary in order to generate the primers that will allow its selective amplification. This means that, typically, PCR users must know the precise sequence(s) upstream of the target region on each of the two single-stranded templates in order to ensure that the DNA polymerase properly binds to the primer-template hybrids and subsequently generates the entire target region during DNA synthesis. The limitation is offset when using arbitrarily amplified DNA techniques such as DNA amplification fingerprinting (DAF) or randomly amplification of polymorphic DNA (RAPD). These DNA profiling methods use arbitrary primers in PCR reactions that do not require sequence knowledge. Like all enzymes, DNA polymerases are also prone to error, which in turn causes mutations in the PCR fragments that are generated. Another limitation of PCR is that even the smallest amount of contaminating DNA can be amplified, resulting in misleading or ambiguous results. To minimize the chance of contamination, investigators should reserve separate rooms for reagent preparation, the PCR, and analysis of product. Reagents should be dispensed into single-use aliquots. Pipettors with disposable plungers and extra-long pipette tips should be routinely used. It is moreover recommended to ensure that the lab set-up follows a unidirectional workflow. No materials or reagents used in the PCR and analysis rooms should ever be taken into the PCR preparation room without thorough decontamination.
Sources: en.wikipedia.org
== History == Tetraoxygen was first predicted in 1924 by Gilbert N. Lewis, who proposed it as an explanation for the failure of liquid oxygen to obey Curie's law. Though not entirely inaccurate, computer simulations indicate that although there are no stable O4 molecules in liquid oxygen, O2 molecules do tend to associate in pairs with antiparallel spins, forming transient O4 units. In 1999, researchers thought that solid oxygen in its ε-phase, also known as red oxygen, (at pressures above 10 GPa) was O4. However, in 2006, it was shown by X-ray crystallography that this stable phase is in fact octaoxygen (O8). Nevertheless, positively charged tetraoxygen has been detected as a short-lived chemical species in mass spectrometry experiments.
Pretargeting (imaging) is a tool for nuclear medicine and radiotherapy. Imaging studies require a high contrast of target to background. This can be provided by using a biomarker which has a high affinity and specificity for its target (e.g. an antibody).
The combination of heroin and xylazine produces a potentially more deadly high than heroin alone. Xylazine is also frequently found in "speedball", a mixture of a stimulant drug such as cocaine with a depressant drug such as heroin, morphine and/or fentanyl. As of 2012, causal factors underlying xylazine's increasing popularity were still unknown. As of 2022, more information on the distribution of xylazine in the body, physical symptoms, and factors predictive of chronic use was known: frequency of use depended on social or economic factors, as well as each user's subjective response to the drug's addictive properties. From November 2021 until August 2022, 80% of drug paraphernalia which tested positive for fentanyl at needle exchange programs in Maryland also contained xylazine. As of 2022, xylazine was almost invariably combined with opioids when used recreationally, and the drug produced a characteristic withdrawal syndrome which complicates treatment of addicted users. In April 2023, the Biden administration declared xylazine-laced fentanyl an official emerging drug threat to the nation, the first time such a label has been given. In 2022, the Drug Enforcement Administration (DEA) reported that 23% of seized fentanyl powder and 7% of fentanyl pills were found to have been adulterated with xylazine. In July 2023, the first death following xylazine use outside of North America was reported to have taken place in Solihull, England on May 22. A 43-year-old male was found dead at home with postmortem toxicology detecting heroin, cocaine, fentanyl and xylazine.
For services to Punjabi and Sikh Heritage, and to Charity. Wayne Ellis Griffiths. Chair, Macmillan's Wales Volunteer Forum and Ambassador and Fundraiser, Velindre Cancer Centre. For services to Fundraising for Cancer Care and Cancer Research. Clare Eluned Frances Gummett. For services to the community in the London Borough of Merton. Eileen Hagan. Volunteer, Blackpool Support Adult Services Unit, Scouts Movement. For services to Young People and to the community in Blackpool. Ian Robert Hague. For services to the community in Sheffield, South Yorkshire. Graham Nelson Hall. Vice President, Nottinghamshire Football Association Ltd. For services to Young People and Sport. Godfrey Williams Harrison. For services to the community in Bude-Stratton, Cornwall. Martin Dymock Harrison. For services to the community in Royal Leamington Spa, Warwickshire and the West Midlands. Stephen Michael Harrison. For services to the Church and to the community in South Petherton, Somerset. Shendl Hastings Harvey (Shendl Russell). Teacher and Dancer, Royal Scottish Official Board of Highland Dancing. For services to Dance. David Kingsley Hastings. Branch Secretary, Royal National Lifeboat Institution Durham Fundraising Branch and Community Presenter. For voluntary services to the Royal National Lifeboat Institution. Nicola June Hawkins. For services to the community in Hastings and Rother, East Sussex. Tracy Hawkins. Assistant Secretary, Special Air Service Regimental Association. For Charitable Services. John Bertram Heasman. President, Dulwich Unit.
As an analytical technique, RIS is useful based on some of its working operations – they include extremely low detection limit so that mass of samples could be identified up to the order of 10−15, the extremely high sensitivity and elemental selectivity useful in micro- and trace analysis when coupled with mass spectrometers, and ability of the pulsed laser ion source to produce pure isobaric ion beams. A major advantage of using resonance ionization is that it is a highly selective ionization mode; it is able to target a single type of atom among a background of many types of atoms, even when said background atoms are much more abundant than the target atoms. In addition, resonance ionization incorporates the high selectivity that is desired in spectroscopy methods with ultrasensitivity, thus making resonance ionization useful when analyzing complex samples with several atomic components. Resonance ionization spectroscopy (RIS) thus has a wide range of research and industrial applications. These include characterizing the diffusion and chemical reaction of free atoms in a gas medium, solid state surface analysis using direct sampling, studying the degree of concentration variations in a dilute vapor, detecting the allowable limits of number of particles needed in a semiconductor device, and estimating the flux of solar neutrinos on Earth.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.