The short version of reversed-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-20. Anything still debated is marked as such rather than presented as settled.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
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.
== Second reconstruction (1941–1958) == A second reconstruction was carried out between 1941 and 1958, initiated by François Jourda de Vaux de Foletier (1893–1988), director of the Seine Archives. This effort, referred to as the "second reconstruction," primarily used documents donated by families, biographical works, and dictionaries. It includes over 400 boxes, organized alphabetically by family name, and classified into births, marriages (listed only under the husband’s name), and deaths. The Archives of Paris continue to receive records or copies of documents to supplement the civil records. These contributions usually come from individuals who uncover materials during their research, effectively extending the "second reconstruction" of Parisian civil records.
The cardiac examination includes inspection, feeling the chest with the hands (palpation) and listening with a stethoscope (auscultation). It involves assessment of signs that may be visible on a person's hands (such as splinter haemorrhages), joints and other areas. A person's pulse is taken, usually at the radial artery near the wrist, in order to assess for the rhythm and strength of the pulse. The blood pressure is taken, using either a manual or automatic sphygmomanometer or using a more invasive measurement from within the artery. Any elevation of the jugular venous pulse is noted. A person's chest is felt for any transmitted vibrations from the heart, and then listened to with a stethoscope.
=== Mothers === For women with PKU, it is important for the health of their children to maintain low Phe levels before and during pregnancy. Though the developing fetus may only be a carrier of the PKU gene, the intrauterine environment can have very high levels of phenylalanine, which can cross the placenta. The child may develop congenital heart disease, growth retardation, microcephaly, and intellectual disability as a result. In most countries, women with PKU who wish to have children are advised to lower their blood Phe levels (typically to between 2 and 6 mg/dL) before they become pregnant, and carefully control their levels throughout the pregnancy. This is achieved by performing regular blood tests and adhering very strictly to a diet, in general, monitored on a day-to-day basis by a specialist metabolic dietitian. In many cases, as the fetus' liver begins to develop and produce PAH normally, the mother's blood Phe levels will drop, requiring an increased intake to remain within the safe range of 2–6 mg/dL. The mother's daily Phe intake may double or even triple by the end of the pregnancy, as a result. When maternal blood Phe levels fall below 2 mg/dL, anecdotal reports indicate that the mothers may experience adverse effects, including headaches, nausea, hair loss, and general malaise. When low phenylalanine levels are maintained for the duration of pregnancy, there are no elevated levels of risk of birth defects compared with a baby born to a non-PKU mother.
Subcutaneous fat is the most widely distributed subcutaneous tissue layer. It is composed of adipocytes, which are grouped together in lobules separated by connective tissue. The number of adipocytes varies among different body areas, while their size varies according to the body's nutritional state. It acts as padding and as an energy reserve, as well as providing some minor thermoregulation via insulation. Subcutaneous fat is found just beneath the skin, as opposed to visceral fat, which is found in the peritoneal cavity, and can be measured using body fat calipers to give a rough estimate of total body adiposity.
Sources: en.wikipedia.org
The cyclol model was consistent with the general properties then attributed to folded proteins. (1) Centrifugation studies had shown that folded proteins were significantly denser than water (~1.4 g/mL) and, thus, tightly packed; Wrinch assumed that dense packing should imply regular packing. (2) Despite their large size, some proteins crystallize readily into symmetric crystals, consistent with the idea of symmetric faces that match up upon association. (3) Proteins bind metal ions; since metal-binding sites must have specific bond geometries (e.g., octahedral), it was plausible to assume that the entire protein also had similarly crystalline geometry. (4) As described above, the cyclol model provided a simple chemical explanation of denaturation and the difficulty of cleaving folded proteins with proteases. (5) Proteins were assumed to be responsible for the synthesis of all biological molecules, including other proteins. Wrinch noted that a fixed, uniform structure would be useful for proteins in templating their own synthesis, analogous to the Watson-Francis Crick concept of DNA templating its own replication. Given that many biological molecules such as sugars and sterols have a hexagonal structure, it was plausible to assume that their synthesizing proteins likewise had a hexagonal structure. Wrinch summarized her model and the supporting molecular-weight experimental data in three review articles.
Protons and neutrons are arranged in shells, just like electrons, and so a closed shell can significantly increase stability: the known superheavy nuclei exist because of such a shell closure, probably at around 114–126 protons and 184 neutrons. They are probably close to a predicted island of stability, where superheavy nuclides should be more long-lived than otherwise expected: predictions for the longest-lived nuclides on the island range from microseconds to millions of years. It should nonetheless be noted that these are essentially extrapolations into an unknown part of the chart of nuclides, and systematic model uncertainties need to be taken into account. As the closed shells are passed, the stabilizing effect should vanish. Thus, superheavy nuclides with more than 184 neutrons are expected to have much shorter lifetimes, spontaneously fissioning within 10−15 seconds. If this is so, then it would not make sense to consider them chemical elements: IUPAC/IUPAP theorizes and recommends an element to exist only if the nucleus lives longer than 10−14 seconds, the time needed for it to gather an electron cloud. Nonetheless, theoretical estimates of half-lives are very model-dependent, ranging over many orders of magnitude. The extreme repulsion between protons is predicted to result in exotic nuclear topologies, with bubbles, rings, and tori expected: this further complicates extrapolation. It is not clear if any further-out shell closures exist, due to an expected smearing out of distinct nuclear shells (as is already expected for the electron shells at oganesson).
Occupational therapy practitioners aim to improve and enable a client or group's participation in meaningful, everyday occupations. In this sense, occupation is defined as any activity that "occupies one's time". Examples of those activities include daily tasks (dressing, bathing, eating, house chores, driving, etc.), sleep and rest, education, work, play, leisure (hobbies), and social interactions. The OT profession offers a vast range of services for all stages of life in a myriad of practice settings, though the foundations of OT come from mental health. OT services focused on mental health can be provided to persons, groups, and populations across the lifespan and experiencing varying levels of mental health performance. For example, occupational therapy practitioners provide mental health services in school systems, military environments, hospitals, outpatient clinics, and inpatient mental health rehabilitation settings. Interventions or support can be provided directly through specific treatment interventions or indirectly by providing consultation to businesses, schools, or other larger groups to incorporate mental health strategies on a programmatic level. Even people who are mentally healthy can benefit from the health promotion and additional prevention strategies to reduce the impact of difficult situations. The interventions focus on positive functioning, sensory strategies, managing emotions, interpersonal relationships, sleep, community engagement, and other cognitive skills (i.e. visual-perceptual skills, attention, memory, arousal/energy management, etc.).
Sources: en.wikipedia.org
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。