ACTH 片段 comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-04-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
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.
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。
PCP is well known for its primary action on the NMDA receptor, an ionotropic glutamate receptor. As such, PCP is a non-competitive NMDA receptor antagonist. The role of NMDAR antagonism in the effect of PCP, ketamine, and related dissociative agents was first published in the early 1980s by David Lodge and colleagues. Other NMDA receptor antagonists include ketamine, tiletamine, dextromethorphan, nitrous oxide, and dizocilpine (MK-801). Research also indicates that PCP inhibits nicotinic acetylcholine receptors (nAChRs) among other mechanisms. Analogues of PCP exhibit varying potency at nACh receptors and NMDA receptors. Findings demonstrate that presynaptic nAChRs and NMDA receptor interactions influence the postsynaptic maturation of glutamatergic synapses and consequently impact synaptic development and plasticity in the brain. These effects can lead to inhibition of excitatory glutamate activity in certain brain regions such as the hippocampus and cerebellum thus potentially leading to memory loss as one of the effects of prolonged use. Acute effects on the cerebellum manifest as changes in blood pressure, breathing rate, pulse rate, and loss of muscular coordination during intoxication. PCP, like ketamine, also acts as a potent dopamine D2High receptor partial agonist in rat brain homogenate and has affinity for the human cloned D2High receptor. This activity may be associated with some of the other more psychotic features of PCP intoxication, which is evidenced by the successful use of D2 receptor antagonists (such as haloperidol) in the treatment of PCP psychosis.
The 2002 sign language law requires government authorities and public agencies to accept and provide information in Língua Brasileira dos Sinais or "LIBRAS", the Brazilian Sign Language, while a 2005 presidential edict extends this to require teaching of the language as a part of the education and speech and language pathology curricula. LIBRAS teachers, instructors and translators are recognized professionals. Schools and health services must provide access ("inclusion") to deaf people. Minority languages are spoken throughout the nation. One hundred and eighty Amerindian languages are spoken in remote areas and a significant number of other languages are spoken by immigrants and their descendants. In the municipality of São Gabriel da Cachoeira, Nheengatu (a currently endangered creole language that, together with its southern relative língua geral paulista, once was a major lingua franca in Brazil), Baniwa and Tucano languages had been granted co-official status with Portuguese. There are significant communities of German (mostly the Brazilian Hunsrückisch, a High German language dialect) and Italian (mostly the Talian, a Venetian dialect) origins in the Southern and Southeastern regions, whose ancestors' native languages were carried along to Brazil, and which, still alive there, are influenced by the Portuguese language. Talian is officially a historic heritage of Rio Grande do Sul, and two German dialects possess co-official status in a few municipalities. Italian is also recognized as "ethnic language" in Santa Teresa and Vila Velha, in the state of Espírito Santo.
In those with the common cold, the color of the sputum or nasal secretion may vary from colorless to yellow to green and does not indicate the class of agent causing the infection. The color of the sputum is determined by immune cells fighting an infection in the nasal area. Vitamin C does not prevent or treat the common cold, although it may have a protective effect during intense cold-weather exercise. If taken daily, it may slightly reduce the duration and severity of colds, but it has no effect if taken after the cold starts. Hand-washing temperature is purely preferential; cold and warm water remove the same amount of germs when using hand soap. To kill germs, water would have to be hot enough to scald one’s hands. Supplements of the plant echinacea do not prevent or reduce the severity of colds as widely believed. A 2014 review of 24 different randomized controlled trials found echinacea supplements do not prevent colds, with most showing no benefit over placebo.
Sources: en.wikipedia.org
=== 238Pu === Plutonium-238 has a half-life of 87.7 years, reasonable power density of 0.57 watts per gram, and exceptionally low gamma and neutron radiation levels. 238Pu has the lowest shielding requirements. Only three candidate isotopes meet the last criterion (not all are listed above) and need less than 25 mm of lead shielding to block the radiation. 238Pu (the best of these three) needs less than 2.5 mm, and in many cases, no shielding is needed in a 238Pu RTG, as the casing itself is adequate. 238Pu has become the most widely used fuel for RTGs, in the form of plutonium(IV) oxide (PuO2). However, plutonium(IV) oxide containing a natural abundance of oxygen emits neutrons at the rate of roughly 2.3×104 n/sec/g of 238Pu. This emission rate is relatively high compared to the neutron emission rate of plutonium-238 metal. The metal containing no light element impurities emits roughly 2.8×103 n/sec/g of 238Pu. These neutrons are produced by the spontaneous fission of 238Pu. The difference in the emission rates of the metal and the oxide is due mainly to the alpha, neutron reaction with the oxygen-18 and oxygen-17 in the oxide. The normal amount of oxygen-18 present in the natural form is 0.204% while that of oxygen-17 is 0.037%. The reduction of the oxygen-17 and oxygen-18 present in the plutonium dioxide will result in a much lower neutron emission rate for the oxide; this can be accomplished by a gas phase 16O2 exchange method.
Hydrophobic molecules: water-insoluble molecules such as diacylglycerol, and phosphatidylinositols, which are membrane-associated and diffuse from the plasma membrane into the intermembrane space where they can reach and regulate membrane-associated effector proteins. Hydrophilic molecules: water-soluble molecules, such as cAMP, cGMP, IP3, and Ca2+, that are located within the cytosol. Gases: nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S) which can diffuse both through cytosol and across cellular membranes. These intracellular messengers have some properties in common:
In fantasy fiction, a lich () is a type of undead creature with magical powers. Various works of fantasy fiction, such as Clark Ashton Smith's "The Empire of the Necromancers" (1932), had used lich as a general term for any corpse, animate or inanimate, before the term's specific use in fantasy role-playing games. The more recent use of the term lich for a specific type of undead creature originates from the 1976 Dungeons & Dragons role-playing game booklet Greyhawk, written by Gary Gygax and Rob Kuntz. Often such a creature is the result of a willful transformation, as a powerful wizard skilled in necromancy who seeks eternal life uses rare substances in a magical ritual to become undead. Unlike zombies, which are often depicted as mindless, liches are sapient revenants, retaining their previous intelligence and magical abilities. Liches are often depicted as holding power over lesser mindless undead soldiers and servants. A lich's most commonly depicted distinguishing feature, compared to other undead in fantasy fiction, is the method by which it achieves immortality: liches surrender their souls to create "soul-artifacts" (often called a "soul gem" or "phylactery" in other fantasy works), which serve as the source of their magic and immortality. Many liches take precautions to hide and/or protect one or more of these soul-artifacts, which anchor parts of their souls to the material world.
== Etymology == The name pyrite is derived from the Greek πυρίτης λίθος (pyritēs lithos), 'stone or mineral which strikes fire', in turn from πῦρ (pŷr), 'fire'. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what is now called pyrite. By Georgius Agricola's time, c. 1550, the term had become a generic term for all of the sulfide minerals.
Sources: en.wikipedia.org
In 1933, Schoenheimer emigrated to the United States, where his scientific research took a different focus. Prior to his emigration, his work was mostly focused on the metabolism of cholesterol. In 1934 Schoenheimer began his work on intermediary metabolism, and how stable isotopes could be applied to the study. Schoenheimer worked alongside David Rittenburg and later Konrad Bloch. Schoenheimer and his colleagues began their research by conducting experiments with the use of deuterium. Deuterium, which is a stable isotope of hydrogen, was discovered by physical chemist Harold Urey in 1932. One of the methods used in the experiment involved heavy water administered into animals in order to analyse the deuterium present in the different constituents of the body. This suggested which type of substances were utilising the hydrogen present in body fluids and revealed the role water posed in metabolic processes. Their experiment also provided information regarding the breakdown process of lipid compounds containing deuterium in experimental animals. Prior to this study, it was assumed that animals utilised fats directly from foods that they had recently ingested, and that fat stores were only used amid starvation. The experiment revealed that fatty acids remained stored in body depots even during starvation. Schoenheimer and his colleagues then began a study of protein metabolism using the isotope of nitrogen as it became available. Schoenheimer and his colleague David Rittenberg, analysed how synthesised amino acids containing nitrogen would operate within an animal's body.
Occasionally a radiologic diagnosis of disc degeneration is made incidentally when a cervical X-ray, chest X-ray, or abdominal X-ray is taken for other reasons and the abnormalities of the vertebral column are recognized. The diagnosis of DDD is not a radiologic diagnosis, since the interpreting radiologist is not aware whether there are symptoms. Typical radiographic findings include disc space narrowing, displacement of vertebral bodies, fusion of adjacent vertebral bodies, and development of bone in adjacent soft tissue (osteophyte formation). An MRI is typically reserved for those with symptoms, signs, and X-ray findings suggesting a need for surgical intervention. Treatment may include physical therapy for pain relief, ROM (range of motion), and appropriate muscle/strength training, with emphasis on correcting abnormal posture, assisting the paravertebral (paraspinous) muscles in stabilizing the spine, and core muscle strengthening; stretching exercises; massage therapy; oral analgesia with non-steroidal anti-inflammatory agents (NSAIDS); and topical analgesia with lidocaine, ice, and heat. Immediate surgery may be indicated if the symptoms are severe or sudden in onset, or suddenly worsen. Elective surgery may be indicated after six months of conservative therapy with unsatisfactory relief of symptoms.
== Pathophysiology == GPS is caused by abnormal plasma cell production of anti-GBM antibodies. The major target of these abnormal antibodies is the non-collagen domain of the alpha-3 chain of type 4 collagen, which is mostly found in the basal membranes of glomerular and alveolar capillaries, explaining the obscurely specific symptoms of this condition. This preferred targeting of these alpha-3 collagen chains specifically in the basal membranes of glomerular and alveolar capillaries can be explained by the higher accessible exposure of epitopes, a larger expansion of the alpha-3 collagen units, and because these alpha-3 collagen chains structurally provide higher accessibility for the targeting antibodies. These antibodies bind their reactive epitopes to the basement membranes and activate the complement cascade, leading to the death of tagged cells. A specific antibody and epitope binding that shows the highest affinity and is pathogenic occurs between GPA antibodies and the anti-GBM epitope region, designated EA, which is residues 17–31 of the alpha 3 subunit of non-collagenous domain of type IV collagen. T cells are also implicated, though it is generally considered a type II hypersensitivity reaction.
== Prognosis == Necrobiosis Lipoidica is classically chronic, difficult to manage, and treat. The prognosis is not reassuring. Squamous cell carcinoma is often a concern with NL. However, this occurs very late into the diagnosis Treatment can typically stop the growth of lesions and ulcers. Lesion treatment is often exquisitely painful and requires intensive wound care. Aesthetically, wounds rarely heal without scarring.
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Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.