A practical reference on lyophilisation: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-04 and is reviewed periodically as new material appears.
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
| Property | Value | Notes |
|---|---|---|
| 化学类别 | 合成七肽 | ACTH(4-10) 结构类似物 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | 单字母写作 MEHFPGP |
| 分子量 | 约 813.9 Da | 随确切形式和盐型略有变化 |
| 常见同义词 | ACTH(4-10) 类似物 | 俄语文献称 Семакс |
| 开发来源 | 俄罗斯 | 二十世纪八十年代 |
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.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Animals, not humans, serve as reservoir species for rabies and are responsible for passing the virus to humans in the overwhelming majority of cases. Therefore to eliminate rabies in an area is to eliminate rabies from the local animal populations, both wild and domestic. Pre-exposure immunization has been used on domesticated and wild populations. In many jurisdictions, domestic dogs, cats, ferrets, and rabbits are required to be vaccinated.
According to one of Liu's generals, education would make it so that “within ten to twenty years, the people will have forgotten even the names of the minority groups.” He established several schools for Tibetans in the borderlands in order to facilitate "Han-Tibetan language exchange". The language of instruction within schools was a matter of much debate within the provincial government, but by 1942, Liu's administration began prioritizing bilingual education in order to encourage Tibetans to learn Chinese. This came along with a slate of other measures aimed at creating a mobile educational system using geshe or khenpo monks to disseminate nationalist values to isolated and nomadic borderland communities. Liu recognized that the monks and lamas held more power in many areas of Xikang than the government; thus, the government would have to co-opt them. As part of this effort, anti-Japanese war propaganda and bilingual newspapers were posted on the walls of temples. Liu Wenhui criticized the Sinicization policies of past Xikang ruler Zhao Erfeng for being "extremist", saying that Zhao "emphasized force and acted too hastily"; however, this must be placed in light of his own contradictory stances.
Clinical trials are only a small part of the research that goes into developing a new treatment. Potential drugs, for example, first have to be discovered, purified, characterized, and tested in labs (in cell and animal studies) before ever undergoing clinical trials. In all, about 1,000 potential drugs are tested before just one reaches the point of being tested in a clinical trial. For example, a new cancer drug has, on average, six years of research behind it before it even makes it to clinical trials. But the major holdup in making new cancer drugs available is the time it takes to complete clinical trials themselves. On average, about eight years pass from the time a cancer drug enters clinical trials until it receives approval from regulatory agencies for sale to the public. Drugs for other diseases have similar timelines. Some reasons a clinical trial might last several years:
Sources: en.wikipedia.org
== Manufacturing/packaging == The processes used to manufacture orally disintegrating tablets include loose compression tabletting, a process which is not very different than the manufacturing method used for traditional tablets and lyophilization processes. In loose compression, ODTs are compressed at much lower forces (4 – 20 kN) than traditional tablets. However, since ODTs are compressed at very low forces due to the need for them to be soft enough to disintegrate rapidly in the mouth, issues of material sticking to the die walls can be challenging. Typically, as in most tablet blends, lubricants such as magnesium stearate are added to the blend to reduce the amount of material that may stick to the die wall. Differences may be the use of disintegrating aids, such as crospovidone, and binding agents that aid in mouth feel, such as microcrystalline cellulose. Primarily, ODTs contain some form of sugar such as mannitol, which typically serves as the major diluent of the ODTs, and is also the primary contributor to the smooth and creamy mouth feel of most ODTs. Lyophilized ODT formulations may use proprietary technologies but can produce a tablet that has a faster disintegration rate, for example the Zydis ODT typically dissolves in the mouth in less than 5 seconds without water and Lyophilized Freeze drying tablets - ODT typically dissolves in the mouth in few seconds depending on the molecules and strength. ODTs are available in HPDE bottles (Parcopa) or individually sealed in blister packs to protect the tablets from damage, moisture, and oxidation.
Serotonin (), also known as 5-hydroxytryptamine (5-HT), is a monoamine neurotransmitter with a wide range of functions in both the central nervous system (CNS) and also peripheral tissues. It is involved in mood, cognition, reward, learning, memory, and physiological processes such as vomiting and vasoconstriction. In the CNS, serotonin regulates mood, appetite, and sleep. Most of the body's serotonin—about 90%—is synthesized in the gastrointestinal tract by enterochromaffin cells, where it regulates intestinal movements. It is also produced in smaller amounts in the brainstem's raphe nuclei, the skin's Merkel cells, pulmonary neuroendocrine cells, and taste receptor cells of the tongue. Once secreted, serotonin is taken up by platelets in the blood, which release it during clotting to promote vasoconstriction and platelet aggregation. Around 8% of the body's serotonin is stored in platelets, and 1–2% is found in the CNS. Serotonin acts as both a vasoconstrictor and vasodilator depending on concentration and context, influencing hemostasis and blood pressure regulation. It plays a role in stimulating myenteric neurons and enhancing gastrointestinal motility through uptake and release cycles in platelets and surrounding tissue. Biochemically, serotonin is an indoleamine synthesized from tryptophan and metabolized primarily in the liver to 5-hydroxyindoleacetic acid (5-HIAA).
DeMarco was inducted into the Italian-American National Hall of Fame on September 9, 1984 for his scientific and humanitarian work. He received two US patents for his work, the first was titled: Treatment of arteriosclerotic diseases. and the second was: Method of treatment of animal and human tissues damaged by burns and frank visible gangrene.
Sources: en.wikipedia.org
== Function == Protein kinase C (PKC) is a family of serine- and threonine-specific protein kinases that can be activated by calcium and the second messenger diacylglycerol. PKC family members phosphorylate a wide variety of protein targets and are known to be involved in diverse cellular signaling pathways. PKC family members also serve as major receptors for phorbol esters, a class of tumor promoters. Each member of the PKC family has a specific expression profile and is believed to play a distinct role in cells. The protein encoded by this gene is one of the PKC family members. This kinase has been shown to be involved in many different cellular functions, such as apoptosis, cardioprotection from ischemia, heat shock response, as well as insulin exocytosis.
=== Sports === According to Bloodworth and McNamee sports and physical activities are a key contributor to the development of people's well-being. The influence of sports on well-being is conceptualized within a framework which includes impermanence, its hedonistic shallowness and its epistemological inadequacy. Researching the effect of sport on well-being is difficult as some societies are unable to access sports, a deficiency in studying this phenomenon.
Tyrosine hydroxylase activity is increased in the short term by phosphorylation. The regulatory domain of tyrosine hydroxylase contains multiple serine (Ser) residues, including Ser8, Ser19, Ser31 and Ser40, that are phosphorylated by a variety of protein kinases. Ser40 is phosphorylated by the cAMP-dependent protein kinase. Ser19 (and Ser40 to a lesser extent) is phosphorylated by the calcium-calmodulin-dependent protein kinase. MAPKAPK2 (mitogen-activated-protein kinase-activating protein kinase) has a preference for Ser40, but also phosphorylates Ser19 about half the rate of Ser40. Ser31 is phosphorylated by ERK1 and ERK2 (extracellular regulated kinases 1&2), and increases the enzyme activity to a lesser extent than for Ser40 phosphorylation. The phosphorylation at Ser19 and Ser8 has no direct effect on tyrosine hydroxylase activity. But phosphorylation at Ser19 increases the rate of phosphorylation at Ser40, leading to an increase in enzyme activity. Phosphorylation at Ser19 causes a two-fold increase of activity, through a mechanism that requires the 14-3-3 proteins. Phosphorylation at Ser31 causes a slight increase of activity, and here the mechanism is unknown. Tyrosine hydroxylase is somewhat stabilized to heat inactivation when the regulatory serines are phosphorylated. Tyrosine hydroxylase is mainly present in the cytosol, although it also is found in some extent in the plasma membrane. The membrane association may be related to catecholamine packing in vesicles and export through the synaptic membrane.
Through the early stages of the game, Combine Civil Protection units pursue Gordon Freeman, the player character, through City 17 after Gordon's presence is mistakenly revealed to Dr. Breen. Due to Gordon's actions in Half-Life and his subsequent disappearance, which earned him a legendary reputation, Dr. Breen sees Gordon as a significant threat. As Gordon flees the city, Civil Protection units raid the resistance base of Black Mesa East and capture resistance leader Eli Vance, who is transferred to holding facilities at Nova Prospekt. Gordon, along with Eli's daughter Alyx, breaks into the facility to rescue him, but Eli is teleported to the Combine Citadel by double agent Judith Mossman. The strike against Nova Prospekt prompts a revolution by the citizens of Earth and heavy street fighting takes place. In Episode One, the destruction of the teleporter has isolated Combine forces on Earth, and its primary reactor has begun to melt down. This forces Gordon and Alyx to journey back into the critically damaged Citadel to stabilize its reactor while the city's inhabitants are evacuated. The Combine forces, however, instead attempt to accelerate the meltdown in order to contact their native dimension for reinforcements. After Alyx acquires an encrypted copy of the message to be sent, Overwatch forces desperately attempt to stop the pair from escaping the city, spurred on by Combine Advisors. As the pair escape on a train at the end of the game, the Citadel detonates and destroys City 17.
Sources: en.wikipedia.org
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。
Semax 被描述为 ACTH(4-10) 的结构类似物，两者共享部分序列特征。它保留了该片段的部分神经相关活性方向，但去除了完整片段带来的激素释放效应。二者并非同一物质，也不能互相替代。
加入的 Pro-Gly-Pro 三肽被普遍认为能提升分子对蛋白水解酶的稳定性。这种设计让短肽在体内维持时间更长。具体延长的程度以及不同组织中是否一致，文献中仍存在不同报告。
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.