This is a working overview of BDNF, written for readers who want more than a one-paragraph summary but less than a textbook.
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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.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
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.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
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.
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.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
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。
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。
== Mechanical bonding and chemical reactivity == The introduction of a mechanical bond alters the chemistry of the sub components of rotaxanes and catenanes. Steric hindrance of reactive functionalities is increased and the strength of non-covalent interactions between the components are altered.
On the other hand, if the idea of a smaller Germany won out, the German crown could of course not possibly go to the Emperor of Austria, but would naturally be offered to the head of the largest and most powerful German state outside of Austria—the King of Prussia. The contest between the two ideas, quickly developed into a contest between Austria and Prussia. After Prussia decisively won the Seven Weeks War, this question was solved; Austria lost no territories to Prussia as long as they remained out of German affairs.
==== MeSH D12.776.964.775.375 – gene products, pol (gene) ==== MeSH D12.776.964.775.375.325 – fusion proteins, gag-pol MeSH D12.776.964.775.375.335 – hiv integrase MeSH D12.776.964.775.375.340 – HIV protease MeSH D12.776.964.775.375.750 – RNA-directed DNA polymerase MeSH D12.776.964.775.375.750.375 – hiv-1 reverse transcriptase
In an article published by Los Alamos National Laboratory, researchers state, "Because of the very high strength of pure fentanyl powder, it's hard to dilute precisely, so small inaccuracies in weight can cause huge variation between batches, and it's all too easy for someone to get too much."
Sources: en.wikipedia.org
The American Way supermercato the year before and Supermarket USA were among the first of several instances in which American supermarkets were deployed internationally at the height of the Cold War as shock and awe instruments of American propaganda to demonstrate the supposed superiority of Western Bloc capitalism over Eastern Bloc communism. Before then, a few countries had already begun to implement supermarkets due to their proximity to or affinity for the United States. Canada, to the north, had implemented the new retail format at the same time during the 1930s. For example, Québec's first supermarket opened in 1934 in Montréal, under the banner Steinberg's. In Canada, the largest supermarket chain is Loblaw, which operates stores under a variety of banners targeted to different segments and regions, including Fortinos, Zehrs, No Frills, the Real Canadian Superstore, and Loblaws, the foundation of the company. Sobeys is Canada's second largest supermarket with locations across the country, operating under many banners (Sobeys IGA in Quebec). In the United Kingdom, self-service shopping took longer to become established, despite its Special Relationship with the United States. In 1947, there were just ten self-service shops in the country. In 1951, ex-US Navy sailor Patrick Galvani, son-in-law of Express Dairies chairman, made a pitch to the board to open a chain of supermarkets across the country.
September 20, 2010: United States The National Bureau of Economic Research state that the US left the recession in June 2009, with managing director Lakshman Achuthan of the Economic Cycle Research Institute saying GDP recovered to 70% of the pre-recession level.
Researchers are investigating biomarkers to help diagnose MS, to inform prognoses, and track response to medication. Ideally, biomarker would be detectable in blood, as cerebrospinal fluid is more difficult to access. Three biomarkers are emerging as candidates for real-world applications: Neurofilament light chain (NfL), chitinase-3-like protein 1 (CHI3L1) and glial fibrillary acidic protein (GFAP). NfL levels are elevated years before people typically get an MS diagnosis, and is of interest as a potential screening tool. GFAP and CHI3L1 may be able to track progression independent if relapse activity, and be used as disease progress markers.
== Detectors == A time-of-flight mass spectrometer (TOFMS) consists of a mass analyzer and a detector. An ion source (either pulsed or continuous) is used for lab-related TOF experiments, but not needed for TOF analyzers used in space, where the sun or planetary ionospheres provide the ions. The TOF mass analyzer can be a linear flight tube or a reflectron. The ion detector typically consists of microchannel plate detector or a fast secondary emission multiplier (SEM) where first converter plate (dynode) is flat. The electrical signal from the detector is recorded by means of a time to digital converter (TDC) or a fast analog-to-digital converter (ADC). TDC is mostly used in combination with orthogonal-acceleration (oa)TOF instruments. Time-to-digital converters register the arrival of a single ion at discrete time "bins"; a combination of threshold triggering and constant fraction discriminator (CFD) discriminates between electronic noise and ion arrival events. CFD converts nanosecond-long Gaussian-shaped electrical pulses of different amplitudes generated on the MCP's anode into common-shape pulses (e.g., pulses compatible with TTL/ESL logic circuitry) sent to TDC. Using CFD provides a time point correspondent to a position of peak maximum independent of variation in the peak amplitude caused by variation of the MCP or SEM gain.
=== Legal status === Migalastat was authorized for medical use in the European Union in May 2016, and approved for medical use in the United States in August 2018. The FDA granted approval of Galafold to Amicus Therapeutics U.S., Inc. The US Food and Drug Administration (FDA) granted the application for migalastat priority review and orphan drug designations. The European Medicines Agency granted it orphan drug designation in 2006.
Sources: en.wikipedia.org
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.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.