This is a working overview of melanocortin signalling, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-15 and is reviewed periodically as new material appears.
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.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
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。
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 |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
Automated cell counters sample the blood, and quantify, classify, and describe cell populations using both electrical and optical techniques. Electrical analysis involves passing a dilute solution of the blood through an aperture across which an electrical current is flowing. The passage of cells through the current changes the impedance between the terminals (the Coulter principle). A lytic reagent is added to the blood solution to selectively lyse the red cells (RBCs), leaving only white cells (WBCs), and platelets intact. Then the solution is passed through a second detector. This allows the counts of RBCs, WBCs, and platelets to be obtained. The platelet count is easily separated from the WBC count by the smaller impedance spikes they produce in the detector due to their lower cell volumes. Optical detection may be utilised to gain a differential count of the populations of white cell types. A dilute suspension of cells is passed through a flow cell, which passes cells one at a time through a capillary tube past a laser beam. The reflectance, transmission and scattering of light from each cell is analysed by sophisticated software giving a numerical representation of the likely overall distribution of cell populations. Some of the latest haematology instruments may report Cell Population Data that consist in Leukocyte morphological information that may be used for flagging Cell abnormalities that trigger the suspect of some diseases. Reticulocyte counts can now be performed by many analysers, giving an alternative to time-consuming manual counts.
There are three main fermentation methods, warm, cool, and wild or spontaneous. Fermentation may take place in open or closed vessels. There may be a secondary fermentation which can take place in the brewery, in the cask or in the bottle. Brewing yeasts have traditionally been described as "top-fermenting" or "bottom-fermenting", and may be "top-cropped" or "bottom-cropped" according to where the yeast is collected from the fermentation vessel to be reused for the next brew. The yeasts classed as top-fermenting are generally used in warm fermentations, where they ferment quickly, and the yeasts classed as bottom-fermenting are used in cooler fermentations where they ferment more slowly. This terminology is somewhat inappropriate in the modern era; after the widespread application of brewing mycology it was discovered that the two separate collecting methods involved two different yeast species that favoured different temperature regimes, namely Saccharomyces cerevisiae in top-cropping at warmer temperatures and Saccharomyces pastorianus in bottom-cropping at cooler temperatures. As brewing methods changed in the 20th century, cylindro-conical fermenting vessels became the norm and the collection of yeast for both Saccharomyces species is done from the bottom of the fermenter. Thus the method of collection no longer implies a species association. There are a few remaining breweries who collect yeast by top-cropping, such as Samuel Smith's in Yorkshire using Yorkshire Squares, and several German hefeweizen producers.
Birds' diets are varied and often include nectar, fruit, plants, seeds, carrion, and various small animals, including other birds. The digestive system of birds is unique, with a crop for storage and a gizzard that contains swallowed stones for grinding food to compensate for the lack of teeth. Some species such as pigeons and some psittacine species do not have a gallbladder. Most birds are highly adapted for rapid digestion to aid with flight. Some migratory birds have adapted to use protein stored in many parts of their bodies, including protein from the intestines, as additional energy during migration. Birds that employ many strategies to obtain food or feed on a variety of food items are called generalists, while others that concentrate time and effort on specific food items or have a single strategy to obtain food are considered specialists. Avian foraging strategies can vary widely by species. Many birds glean for insects, invertebrates, fruit, or seeds. Some hunt insects by suddenly attacking from a branch. Those species that seek pest insects are considered beneficial 'biological control agents' and their presence encouraged in biological pest control programmes. Combined, insectivorous birds eat 400–500 million metric tons of arthropods annually. Nectar feeders such as hummingbirds, sunbirds, lories, and lorikeets amongst others have specially adapted brushy tongues and in many cases bills designed to fit co-adapted flowers.
Sources: en.wikipedia.org
Corticosteroids such as prednisolone, deflazacort, and vamorolone (Agamree) lead to short-term improvements in muscle strength and function up to 2 years. Corticosteroids have also been reported to help prolong walking, though the evidence for this is not robust. Disease-specific physical therapy helps maintain muscle strength, flexibility, and function. It aims to: Minimize the development of contractures and deformity by developing a program of stretches and exercises where appropriate Anticipate and minimize other secondary complications of physical nature by recommending bracing and durable medical equipment Monitor respiratory function and advise on techniques to assist with breathing exercises and methods of clearing secretions Orthopedic appliances (such as braces and wheelchairs) may improve mobility and the ability for self-care. Form-fitting removable leg braces that hold the ankle in place during sleep can defer the onset of contractures. Appropriate respiratory support as the disease progresses is important. Cardiac problems may require a pacemaker. The medication eteplirsen, a Morpholino antisense oligo, has been approved in the United States for the treatment of mutations amenable to dystrophin exon 51 skipping. The US approval has been controversial as eteplirsen failed to establish a clinical benefit; it has been refused approval by the European Medicines Agency. The medication ataluren (Translarna) is approved for use in the European Union.
1993/729) Income Tax (Sub-contractors in the Construction Industry) Regulations 1993 (S.I. 1993/743) Income Tax (Employments) Regulations 1993 (S.I. 1993/744) Health and Safety (Miscellaneous Modifications) Regulations 1993 (S.I. 1993/745) Access to Health Records (Control of Access) Regulations 1993 (S.I. 1993/746) Prevention of Terrorism (Temporary Provisions) Act 1989 (Continuance) Order 1993 (S.I. 1993/747) Combined Probation Areas (Northumbria) Order 1993 (S.I. 1993/748) Combined Probation Areas (Staffordshire) Order 1993 (S.I. 1993/749) Combined Probation Areas (Surrey) Order 1993 (S.I. 1993/750) Medicines Control Agency Trading Fund Order 1993 (S.I. 1993/751) Bingo Duty (Exemptions) Order 1993 (S.I. 1993/752) Finance Act 1989, section 158(1) and (2), (Appointed Days) Order 1993 (S.I. 1993/753) Finance Act 1989, section 178(1), (Appointed Day) Order 1993 (S.I. 1993/754) Income Tax (Indexation) Order 1993 (S.I. 1993/755) Personal Equity Plan (Amendment) Regulations 1993 (S.I. 1993/756) Retirement Benefits Schemes (Indexation of Earnings Cap) Order 1993 (S.I. 1993/757) Taxes (Interest Rate) (Amendment No. 2) Regulations 1993 (S.I. 1993/758) Inheritance Tax (Indexation) Order 1993 (S.I. 1993/759) Capital Gains Tax (Annual Exempt Amount) Order 1993 (S.I. 1993/760) Value Added Tax (Accounting and Records) (Amendment) Regulations 1993 (S.I. 1993/761) Value Added Tax (Cash Accounting) (Amendment) Regulations 1993 (S.I. 1993/762) Value Added Tax (Education) Order 1993 (S.I. 1993/763) Value Added Tax (General) (Amendment) (No. 2) Regulations 1993 (S.I.
== Taxonomy == Amanita virosa was first described in 1838 by Swedish mycologist Elias Magnus Fries as Agaricus virosus, but this name is illegitimate since it had already been used for an earlier and different species. Amanita virosa was legitimately published by French mycologist Louis-Adolphe Bertillon in 1866.
Sources: en.wikipedia.org
In the version often prepared in the United States today in restaurants and hotels, it consists of strips of beef filet with a mushroom, onion, and sour cream sauce, and is served over rice or noodles. Today, the dish is generally served over wide or twisted egg noodles in the United States.
As governor, Newsom has focused on infrastructure, housing, climate, gun control and LGBTQ rights. In 2025, he began hosting the podcast This Is Gavin Newsom, which has featured guests from across the political spectrum. He oversaw the passage of California Proposition 50, a gerrymandering proposal developed in response to 2025 Texas redistricting. Newsom is a potential 2028 presidential candidate.
==== Cleavage of precursor proteins ==== Many proteins and hormones are synthesized in the form of their precursors - zymogens, proenzymes, and prehormones. These proteins are cleaved to form their final active structures. Insulin, for example, is synthesized as preproinsulin, which yields proinsulin after the signal peptide has been cleaved. The proinsulin is then cleaved at two positions to yield two polypeptide chains linked by two disulfide bonds. Removal of two C-terminal residues from the B-chain then yields the mature insulin. Protein folding occurs in the single-chain proinsulin form which facilitates formation of the ultimate inter-peptide disulfide bonds, and the ultimate intra-peptide disulfide bond, found in the native structure of insulin. Proteases in particular are synthesized in the inactive form so that they may be safely stored in cells, and ready for release in sufficient quantity when required. This is to ensure that the protease is activated only in the correct location or context, as inappropriate activation of these proteases can be very destructive for an organism. Proteolysis of the zymogen yields an active protein; for example, when trypsinogen is cleaved to form trypsin, a slight rearrangement of the protein structure that completes the active site of the protease occurs, thereby activating the protein. Proteolysis can, therefore, be a method of regulating biological processes by turning inactive proteins into active ones.
Sources: en.wikipedia.org
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.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
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。