The short version of lyophilized powder fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-04-13. Anything still debated is marked as such rather than presented as settled.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
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.
| Property | Value | Notes |
|---|---|---|
| 外观 | 白色至类白色粉末 | 常见于冻干制剂 |
| 溶解度 | 易溶于水 | 在极性溶剂中一般也可溶 |
| 建议储存温度 | -20 °C | 冻干粉，避光密封 |
| 常见分析手段 | 反相高效液相色谱 | 常与质谱联用 |
| 主要降解路径 | 水解与氧化 | 溶液状态更显著 |
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.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
The human body is composed of elements including hydrogen, oxygen, carbon, calcium and phosphorus. These elements reside in trillions of cells and non-cellular components of the body. The adult male body is about 60% total body water content of some 42 litres (9.2 imp gal; 11 US gal). This is made up of about 19 litres (4.2 imp gal; 5.0 US gal) of extracellular fluid including about 3.2 litres (0.70 imp gal; 0.85 US gal) of blood plasma and about 8.4 litres (1.8 imp gal; 2.2 US gal) of interstitial fluid, and about 23 litres (5.1 imp gal; 6.1 US gal) of fluid inside cells. The content, acidity and composition of the water inside and outside cells is carefully maintained. The main electrolytes in body water outside cells are sodium and chloride, whereas within cells it is potassium and other phosphates.
Sir Charles Sydly ... [came] in open day into the Balcone and showed his nakedness, ... and abusing of scripture and as it were from thence preaching a mountebank sermon from the pulpit, saying that there he had to sell such a powder as should make all the [women] in town run after him, 1000 people standing underneath to see and hear him. And that being done he took a glass of wine … and then drank it off, and then took another and drank the King’s health.
The production of 293Og and its daughter 289Lv, as well as the even heavier isotope 297Og, is also possible using this reaction. The isotopes 295Og and 296Og may also be produced in the fusion of 248Cm with 50Ti projectiles. These heavier and likely more stable isotopes may be useful in probing the chemistry of oganesson. A search in 2017 at RIKEN using this reaction was unsuccessful.
== Location and characteristics == The location of prolactin cells within the pituitary gland is regulated largely by the hypothalamus. The pituitary gland is divided into posterior and anterior regions. Within the anterior pituitary gland are the prolactin cells, where they secrete the hormone prolactin. Prolactin cells vary in number, size, and appearance depending on female reproductive status. Prolactin cells specifically increase in response to the physiological state of pregnancy, in particular, the need for the development of breast tissues and milk production. During pregnancy, prolactin cells will undergo hypertrophy (enlarging to support increased prolactin production) as well as hyperplasia (an increase in cell number). The pituitary gland increases in size due to the amount of prolactin cells. The secretory granules of prolactin cells fluctuate from sparsely granulated (during periods of low prolactin production) to densely granulated (during periods of high prolactin production). Prolactin cells contain a large amount of rough endoplasmic reticulum, where prolactin synthesis occurs. The trans-Golgi layer is responsible for storing the prolactin hormone into secretory granules, which are dissolved upon secretion out of the cell. Lysosomal enzymes are involved in the degradation of the secretory granules. The prolactin hormone is a single polypeptide chain protein composed of 199 amino acids in humans. It consists of “three intramolecular disulfide bonds located between six cysteine residues (Cys4-Cys11, Cys58-Cys174, and Cys191-Cys199”.
Sources: en.wikipedia.org
== Contraindications == Anyone who is unstable for surgery should not undergo flap surgery. As with most surgeries, people who are sicker may have more difficulties with wound healing. Comorbidities include diabetes, smoking, immunosuppression, and vascular disease.
Homoarginine is an nonproteinogenic alpha-amino acid. It is structurally equivalent to a one-methylene group-higher homolog of arginine and to the guanidino derivative of lysine. L-Homoarginine is the naturally occurring enantiomer. Physiologically, homoarginine increases nitric oxide (NO) supply and betters endothelial functions in the body, with a particular correlation and effect towards cardiovascular outcome and mortality. At physiological pH, homoarginine is cationic: the guanidino group is protonated.
== 90Sr contamination in the environment == 90Sr is not quite as likely as 137Cs to be released as a part of a nuclear reactor accident because it is much less volatile, but is probably the most dangerous component of the radioactive fallout from a nuclear weapon. A study of hundreds of thousands of deciduous teeth, collected by Dr.Louise Reiss and her colleagues as part of the Baby Tooth Survey, found a large increase in 90Sr levels through the 1950s and early 1960s. The study's final results showed that children born in St. Louis, Missouri, in 1963 had levels of 90Sr in their deciduous teeth that was 50 times higher than that found in children born in 1950, before the advent of large-scale atomic testing. Reviewers of the study predicted that the fallout would cause increased incidence of disease in those who absorbed 90Sr into their bones. However, no follow up studies of the subjects have been performed, so the claim is untested. An article with the study's initial findings was circulated to U.S. President John F. Kennedy in 1961, and helped convince him to sign the Partial Nuclear Test Ban Treaty with the United Kingdom and Soviet Union, ending the above-ground nuclear weapons testing that placed the greatest amounts of nuclear fallout into the atmosphere. The Chernobyl disaster released roughly 10 PBq, or about 5% of the core inventory, of 90Sr into the environment. The Kyshtym disaster released 90Sr and other radioactive material into the environment. It is estimated to have released 20 MCi (800 PBq) of radioactivity.
Sources: en.wikipedia.org
== Early life and education == Meir Wilchek was born in Warsaw, Poland, scion of a rabbinical family. During the Holocaust, he escaped from the German-occupied territories to the territories occupied by Russia, and was transferred to Siberia, while his father, who served as a community rabbi in Warsaw, was killed in Flossenbürg concentration camp. He survived, and immigrated to Israel in 1949 with his mother and sister. He graduated with B.Sc. in chemistry from Bar Ilan university and Ph.D. in biochemistry from the Weizmann Institute of Science. Wilchek has published over 400 scientific papers, and consulted various biotech companies. He was also in the party list of Mafdal and Meimad for the Knesset.
== Receptors == Relaxin interacts with the relaxin receptor LGR7 (RXFP1) and LGR8 (RXFP2), which belong to the G protein-coupled receptor superfamily. They contain a heptahelical transmembrane domain and a large glycosylated ectodomain, distantly related to the receptors for the glycoproteohormones, such as the LH-receptor or FSH-receptor. Relaxin receptors have been found in the heart, smooth muscle, the connective tissue, and central and autonomous nervous system.
US international involvement in drug control rests on the premise that assisting foreign governments in their anti-drug efforts reduces drug supply within the US. Scholars have claimed that the war on drugs, a metaphorical war, is propaganda cloaking an extension of earlier military or paramilitary operations. Others have argued that large amounts of anti-drug foreign aid money, training, and equipment actually goes to fighting leftist insurgencies and is often provided to groups who themselves are involved in large-scale narco-trafficking, such as corrupt members of the Colombian military.
An onkoknife, iKnife, or intelligent scalpel is a surgical knife that tests tissue as it contacts it during an operation and immediately gives information as to whether that tissue contains cancer cells. During a surgery this information is given continuously to the surgeon, significantly accelerating biological tissue analysis and enabling identification and removal of cancer cells. Electroknives have been in use since the 1920s and smart knife surgery is not limited only to cancer detection. In clinical studies the iKnife has shown impressive diagnostic accuracy - distinguishing benign ovarian tissue from cancerous tissue (97.4% sensitivity, 100% specificity), breast tumour from normal breast tissue (90.9% sensitivity, 98.8% specificity) and recognises histological features of poor prognostic outcome in colorectal carcinoma. Furthermore, the technology behind iKnife - rapid evaporative ionisation mass spectrometry (REIMS) - can identify Candida yeasts down to species level.
Sources: en.wikipedia.org
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。
公开资料对此没有统一答案。普遍建议现配现用，或冷藏并在数日内用完。含甲硫氨酸的序列更易氧化，放置时间越长风险越高。
反相高效液相色谱是最常用的手段，配合质谱确认分子量。氨基酸组成分析和肽图分析可补充序列层面的验证。
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.