The short version of neurotrophic factor fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-07-28 and is reviewed periodically as new material appears.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
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.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
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.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
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。
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。
In MCCs, there is no deconvolution required to determine which compounds are biologically active, because each synthesis in an array has only a single product, thus the identity of the compound should be unequivocally known.
When T. rex was first discovered, the humerus was the only element of the forelimb known. For the initial mounted skeleton as seen by the public in 1915, Osborn substituted longer, three-fingered forelimbs like those of Allosaurus. A year earlier, Lawrence Lambe described the short, two-fingered forelimbs of the closely related Gorgosaurus. This strongly suggested that T. rex had similar forelimbs, but this hypothesis was not confirmed until the first complete T. rex forelimbs were identified in 1989, belonging to MOR 555 (the "Wankel rex"). The remains of Sue also include complete forelimbs. T. rex arms are very small relative to overall body size, measuring only 1 meter (3.3 ft) long, and some scholars have labelled them as vestigial. However, the bones show large areas for muscle attachment, indicating considerable strength. This was recognized as early as 1906 by Osborn, who speculated that the forelimbs may have been used to grasp a mate during copulation. Newman (1970) suggested that the forelimbs were used to assist Tyrannosaurus in rising from a prone position. Since then, other functions have been proposed, although some scholars find them implausible. Padian (2022) argued that the reduction of the arms in tyrannosaurids did not serve a particular function but was a secondary adaptation, stating that as tyrannosaurids developed larger and more powerful skulls and jaws, the arms got smaller to avoid being bitten or torn by other individuals, particularly during group feedings.
Cone snails, or cones, are highly venomous sea snails that constitute the family Conidae. Conidae is a taxonomic family (previously subfamily) of predatory marine gastropod molluscs in the superfamily Conoidea. As of 2014, cone snails are the only member of the superfamily Conoidea. Some previous classifications grouped the cone snails in a subfamily, Coninae. As of March 2015 Conidae contained over 800 recognized species, varying widely in size from lengths of 1.3 cm to 21.6 cm. Working in 18th-century Europe, Carl Linnaeus knew of only 30 species that are still considered valid. Fossils of cone snails have been found from the Eocene to the Holocene epochs. Cone snail species have shells that are roughly conical in shape. Many species have colorful patterning on the shell surface. Cone snails are almost exclusively tropical in distribution. All cone snails are venomous and capable of stinging. Cone snails use a modified radula tooth and a venom gland to attack and paralyze their prey before engulfing it. The tooth, which is likened to a dart or a harpoon, is barbed and can be extended some distance out from the head of the snail at the end of the proboscis. Cone snail venoms are mainly peptide-based, and contain many different toxins that vary in their effects. The sting of several larger species of cone snails can be serious, and even fatal to humans. Cone snail venom also shows promise for medical use.
=== Other === It was approved for treating ankylosing spondylitis, psoriatic arthritis, psoriasis, rheumatoid arthritis. Infliximab is also prescribed (out of indication) for the treatment of Behçet's disease. Infliximab is the most frequently used biological agent in treating relapsing polychondritis. Half of the patients saw benefit from this treatment, and a few other patients experienced infections that in some cases lead to death. There have been numerous case reports of the efficacy of infliximab in various inflammatory skin conditions diseases; the FDA approved infliximab for chronic severe plaque psoriasis in adults in September 2006. Infliximab has been used off-label in treating refractory sarcoidosis, where other treatments have not been effective. Infliximab has been tested in chronic obstructive pulmonary disease (COPD) but there was no evidence of benefit with the possibility of harm. Infliximab is indicated for steroid refractory checkpoint inhibitor induced colitis, at a dose of 5 to 10 mg/kg. Infliximab has been found to be a safe alternative treatment to a second dose of IVIG for Kawasaki Disease resistant to initial IVIG therapy, showing better outcomes in fever resolution and fewer severe adverse effects such as hemolytic anemia.
Sources: en.wikipedia.org
Manual: Healthcare providers or clinical trial coordinators manually review patient records and available trial criteria to identify potential matches. This might also include manually searching in clinical trial databases. Electronic health records (EHR). Some systems integrate with EHRs to automatically flag patients that may be eligible for trials based on their medical data. These systems may leverage machine learning, artificial intelligence or precision medicine methods to more effectively match patients to trials. These methods are faced with the challenge of overcoming the limitations of EHR records such as omissions and logging errors. Direct-to-patient services: Resources are specialized to support patients in finding clinical trials through online platforms, hotlines, and personalized support.
==== Competitive ==== A competitive inhibitor and substrate cannot bind to the enzyme at the same time. Often competitive inhibitors strongly resemble the real substrate of the enzyme. For example, the drug methotrexate is a competitive inhibitor of the enzyme dihydrofolate reductase, which catalyzes the reduction of dihydrofolate to tetrahydrofolate. The similarity between the structures of dihydrofolate and this drug are shown in the accompanying figure. This type of inhibition can be overcome with high substrate concentration. In some cases, the inhibitor can bind to a site other than the binding-site of the usual substrate and exert an allosteric effect to change the shape of the usual binding-site.
=== United States === In the United States, the Controlled Substances Act of 1970 classified most barbiturates as controlled substances; Barbital, mephobarbital, and phenobarbital are designated schedule IV drugs. Additionally, and "Any substance which contains any quantity of a derivative of barbituric acid, or any salt of a derivative of barbituric acid" which includes the oxygenated, methylated, and brominated of compounds like enallylprypam) were designated as being schedule III. Under the original CSA, no barbiturates were placed in schedule I, II, or V; however, amobarbital, pentobarbital, and secobarbital are now schedule II controlled substances unless they are in a suppository dosage form. In 1971, the Convention on Psychotropic Substances was signed in Vienna. Designed to regulate amphetamine and various synthetics compounds, the 34th version of the treaty regulates secobarbital as schedule II, amobarbital, butalbital, cyclobarbital, and pentobarbital as schedule III, and allobarbital, barbital, butobarbital, mephobarbital, phenobarbital, butabarbital, and vinylbital as schedule IV on its "Green List". The combination medication Fioricet, consisting of butalbital, caffeine, and paracetamol (acetaminophen), however, is specifically exempted from controlled substance status, while its sibling Fiorinal, which contains aspirin instead of paracetamol and may contain codeine phosphate, remains a schedule III drug.
== Side effects == Myelosuppression, specifically neutropenia, leukopenia, anemia, and thrombocytopenia Diarrhea, nausea, vomiting, stomatitis, and constipation Increased susceptibility to infections Asthenia
=== Pandemics, disinfectants and healthcare systems === Increased antibiotic use during the early waves of the COVID-19 pandemic may exacerbate this global health challenge. Moreover, pandemic burdens on some healthcare systems may contribute to antibiotic-resistant infections. The use of disinfectants such as alcohol-based hand sanitizers, and antiseptic hand wash may also have the potential to increase antimicrobial resistance. Overuse of disinfectants can lead to mutations that induce antimicrobial resistance. On the other hand, "increased hand hygiene, decreased international travel, and decreased elective hospital procedures may have reduced AMR pathogen selection and spread in the short term" during the COVID-19 pandemic. Critically ill patients are prone to infections, and because of that, they often require antimicrobials. The more antimicrobials, the more resistance one becomes to it. Antimicrobial resistance (AMR) significantly strains healthcare systems and national economies. The World Bank estimates that by 2050, AMR could increase healthcare costs by around US$1 trillion and cause global economic losses of US$1–3.4 trillion annually by 2030. Resistant infections are harder to treat, often requiring longer hospital stays, additional tests, and stronger, more expensive medications, placing extra pressure on hospitals and health systems, especially during pandemics. A 2024 United Nations High-Level Meeting on AMR has pledged to reduce deaths associated with bacterial AMR by 10% over the next six years.
Sources: en.wikipedia.org
== Biomedical Science in the 20th century == At this point in history the field of medicine was the most prevalent sub field of biomedical science, as several breakthroughs on how to treat diseases and help the immune system were made. As well as the birth of body augmentations.
== Principle of operations == In peptide biosensors, peptides serve as the selective recognition element due to their amino acid sequence, which also accounts for their tailored binding affinity and specificity towards various analytes. When the analyte interacts with the peptide recognition elements via non-covalent interactions, this interaction produces a change that can be transduced into a measurable signal. Peptides on their own cannot generate a quantifiable signal after binding events with the analytes, they must be bio-conjugated to signal markers. Common detection strategies include optical methods such as fluorescence resonance energy transfer (FRET), electrochemical outputs such as change in current, impedance, or potential, and sometimes mechanical or piezoelectric signals if the peptide-analyte binding alters mass or surface properties. These methods are commonly employed due to their sensitivity and compatibility with small peptide-based interfaces
The study of proteins in vivo is often concerned with the synthesis and localization of the protein within the cell. Although many intracellular proteins are synthesized in the cytoplasm and membrane-bound or secreted proteins in the endoplasmic reticulum, the specifics of how proteins are targeted to specific organelles or cellular structures is often unclear. A useful technique for assessing cellular localization uses genetic engineering to express in a cell a fusion protein or chimera consisting of the natural protein of interest linked to a "reporter" such as green fluorescent protein (GFP). The fused protein's position within the cell can then be cleanly and efficiently visualized using microscopy. Other methods for elucidating the cellular location of proteins requires the use of known compartmental markers for regions such as the ER, the Golgi, lysosomes or vacuoles, mitochondria, chloroplasts, plasma membrane, etc. With the use of fluorescently tagged versions of these markers or of antibodies to known markers, it becomes much simpler to identify the localization of a protein of interest. For example, indirect immunofluorescence will allow for fluorescence colocalization and demonstration of location. Fluorescent dyes are used to label cellular compartments for a similar purpose. Other possibilities exist, as well. For example, immunohistochemistry usually uses an antibody to one or more proteins of interest that are conjugated to enzymes yielding either luminescent or chromogenic signals that can be compared between samples, allowing for localization information.
In contrast to mirtazapine, the selective serotonin reuptake inhibitors, serotonin–norepinephrine reuptake inhibitors, monoamine oxidase inhibitors, and some tricyclic antidepressants acutely increase the general activity of the 5-HT2A, 5-HT2C, and 5-HT3 receptors, leading to a number of negative changes and side effects, the most prominent of which include anorexia, insomnia, nausea, and diarrhea, among others. However, most of these adverse effects are temporary, since down regulation of 5-HT2A receptors eventually occurs following chronic SSRI treatment, and desensitization of 5-HT3 receptors often occurs within a week or less. This is precisely why SSRIs have a delayed antidepressant and anxiolytic effect, and occasionally, an acute anxiogenic effect before down regulation occurs. Mirtazapine, on the other hand, is an antagonist of the 5-HT2A receptor, and antagonists at this receptor typically induce reverse tolerance. Thus, the antidepressant and anxiolytic effects of mirtazapine occur more rapidly than with SSRIs. Furthermore, its reduced incidence of sexual dysfunction (such as loss of libido and anorgasmia) could be a product of negligible binding to the serotonin transporter and antagonism of the 5-HT2A receptors; however, Mirtazapine's high affinity towards and inverse agonism of the 5-HT2C receptors may greatly attenuate those pro-sexual factors (as evidenced by the pro-sexual effects of drugs like m-CPP and lorcaserin which agonize 5-HT2C receptors in a reasonably selective manner).
Sources: en.wikipedia.org
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
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.