The short version of ACTH 片段 fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-09-03 and is reviewed periodically as new material appears.
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。
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。
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
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.
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.
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.
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.
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.
perché alla terra alfin torna repente / precipitevolissimevolmente The word technically violates Italian grammar rules, the correct form being precipitevolissimamente, which is three letters and one syllable shorter. The poet coined the new word to have 11 syllables in the second verse. Other words can be created with a similar (and grammatically correct) mechanism starting from a longer root, winding up with a longer word. Some examples are:
== Disadvantages == The primary disadvantage of in vitro experimental studies is that it may be challenging to extrapolate from the results of in vitro work back to the biology of the intact organism. Investigators doing in vitro work must be careful to avoid over-interpretation of their results, which can lead to erroneous conclusions about organismal and systems biology. For example, scientists developing a new viral drug to treat an infection with a pathogenic virus (e.g., HIV-1) may find that a candidate drug functions to prevent viral replication in an in vitro setting (typically cell culture). However, before this drug is used in the clinic, it must progress through a series of in vivo trials to determine if it is safe and effective in intact organisms (typically small animals, primates, and humans in succession). Typically, most candidate drugs that are effective in vitro prove to be ineffective in vivo because of issues associated with delivery of the drug to the affected tissues, toxicity towards essential parts of the organism that were not represented in the initial in vitro studies, or other issues.
Each trajectory in a Pfold calculation can be relatively short, but many independent trajectories are needed. Long continuous-trajectory simulations have been performed on Anton, a massively parallel supercomputer designed and built around custom application-specific integrated circuits (ASICs) and interconnects by D. E. Shaw Research. The longest published result of a simulation performed using Anton is a 1.112-millisecond simulation of NTL9 at 355 K; a second, independent 1.073-millisecond simulation of this configuration was also performed (and many other simulations of over 250 μs continuous chemical time). In How Fast-Folding Proteins Fold, researchers Kresten Lindorff-Larsen, Stefano Piana, Ron O. Dror, and David E. Shaw discuss "the results of atomic-level molecular dynamics simulations, over periods ranging between 100 μs and 1 ms, that reveal a set of common principles underlying the folding of 12 structurally diverse proteins." Examination of these diverse long trajectories, enabled by specialized, custom hardware, allow them to conclude that "In most cases, folding follows a single dominant route in which elements of the native structure appear in an order highly correlated with their propensity to form in the unfolded state." In a separate study, Anton was used to conduct a 1.013-millisecond simulation of the native-state dynamics of bovine pancreatic trypsin inhibitor (BPTI) at 300 K. Another important application of MD method benefits from its ability of 3-dimensional characterization and analysis of microstructural evolution at atomic scale.
Sources: en.wikipedia.org
=== Hair drug testing === Hair drug testing is a method that can detect drug use over a much longer period of time than saliva, sweat or urine tests. Hair testing is also more robust with respect to tampering. Thus, hair sampling is preferred by the US military and by many large corporations, which are subject to Drug-Free Workplace Act of 1988. Head hair normally growth at the rate of 0.5 inches per month. Thus, the most common hair sample length of 1.5" from the scalp would detect drug use within the last 90-100 days. 80-120 strands of hair are sufficient for the test. In the absence of hair on the head, body hair can be used as an acceptable substitute. This includes facial hair, the underarms, arms, and legs or even pubic hair. Because body hair usually grows slower than head hair, drugs can often be detected in body hair for longer periods, e.g. up to 12 months. Most drugs are analysed in hair samples not as the original psychoactive molecules, but rather as their metabolytes. For example, ethanol is determined as ethyl glucuronide, while cocaine use is confirmed using ecgonine. Testing for metabolytes reduces the likelihood of false positive results due to contamination. One disadvantage of hair testing is, that it cannot detect recent drug use, because it takes at least a week after a drug intake for the metabolytes to show up in a growing hair above the skin. Urine tests are better suited for detecting recent (within a week) drug use.
His plan fails and he rejoins Freeman's group. Freeman then finds Bubby stuck in his old test tube, who had also been betrayed by the military, along with Benry. Freeman reluctantly allows them to rejoin the group. The science team proceed to Black Mesa's Mixology Department, headed by Darnold (Logmore), who gives Freeman a potion that causes his missing arm to regrow into a machine gun. The team fight their way to the Lambda Complex, where they teleport to Xen. In Xen, they find Benry has grown into a giant and begins floating around the others, taunting them. Benry is revealed to be the source of the resonance cascade, transforming into a monstrous alien form and attacking the rest of the science team, who work together to eventually defeat him, by time traveling to the beginning of the game to retrieve their passports. After defeating Benry, Freeman is captured by the G-Man (Spaghoner), who thanks him for taking down Benry and invites him to the birthday party of Tommy, revealed to be the G-Man's adopted son. In the credits sequence, the science team and the G-Man celebrate Tommy's birthday at a Chuck E. Cheese, much to Freeman's despair. In a post-credits scene, Dr. Coomer calls Freeman and congratulates him for beating the game, thanking him for taking the science team with him on his adventure.
Although sublingual administration of estradiol has a relatively short duration, the medication can be administered multiple times per day in divided doses to compensate for this. Studies that used high doses of sublingual estradiol in the treatment of severe postpartum depression have administered a dose of 1 mg 3 to 8 times per day. In one study, which administered a mean total dosage of sublingual estradiol of 4.8 mg/day, estradiol levels remained elevated at about 130 pg/mL on average in the morning before the first dose of the day. Oral micronized estradiol valerate tablets can be taken sublingually as well. The administration of 2 mg oral micronized estradiol valerate tablets (Progynova, Schering) sublingually 3 or 4 times per day resulted in circulating estradiol levels of about 290 pg/mL to 460 pg/mL in premenopausal women (time of measurements not given). Steady-state levels of estradiol were achieved within about 5 or 6 days. Levels of progesterone, luteinizing hormone, and follicle-stimulating hormone were all considerably suppressed, and ovulation, as well as the associated mid-cycle hormonal surges, were prevented. Sublingual estradiol valerate is used for cycle control in egg donation and surrogacy in cisgender women and is used in hormone therapy for transgender women. Cyclodextrin-containing formulations of sublingual estradiol with improved water solubility and absorption have been developed and studied.
Sources: en.wikipedia.org
== Scientific use == α-Amanitin is a selective inhibitor of RNA polymerase II and III but not I. This mechanism makes it a deadly toxin. α-Amanitin can also be used to determine which types of RNA polymerase are present. This is done by testing the sensitivity of the polymerase in the presence of α-amanitin. RNA polymerase I is insensitive, RNA polymerase II is highly sensitive (inhibited at 1μg/ml), RNA polymerase III is moderately sensitive (inhibited at 10μg/ml), and RNA polymerase IV is slightly sensitive (inhibited at 50μg/ml).
In the body, elastin is usually associated with other proteins in connective tissues. Elastic fiber in the body is a mixture of amorphous elastin and fibrous fibrillin. Both components are primarily made of smaller amino acids such as glycine, valine, alanine, and proline. The total elastin ranges from 58 to 75% of the weight of the dry defatted artery in normal canine arteries. Comparison between fresh and digested tissues shows that, at 35% strain, a minimum of 48% of the arterial load is carried by elastin, and a minimum of 43% of the change in stiffness of arterial tissue is due to the change in elastin stiffness.
Collagen is a primary structural protein in the human body, necessary for healthy blood vessels, muscle, skin, bone, cartilage, and other connective tissues. Defective connective tissue leads to fragile capillaries, resulting in abnormal bleeding, bruising, and internal hemorrhaging. Collagen is an important part of bone, so bone formation is also affected. Teeth loosen, bones break more easily, and once-healed breaks may recur. Defective collagen fibrillogenesis impairs wound healing. Untreated scurvy is invariably fatal. Vitamin C deficiency may cause pulmonary hypertension by several mechanisms. It participates in the synthesis of type IV collagen, which is required for basement membrane formation and endothelial cell adhesion. It also participates in the synthesis of NO and carnitine, and may increase prostacyclin levels. Vitamin C also participates in the hydroxylation of specific proline residues of HIF-1α and thereby increases its rate of degradation, leading to decreased HIF-1α levels.
Sources: en.wikipedia.org
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。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.