If you have been reading about Lyophilisation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-09-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Circulation time for the peptide is short because peptidases cleave it readily. The Pro-Gly-Pro tail is thought to slow breakdown compared with the bare ACTH fragment, but the gain appears modest. Absorption after intranasal dosing is limited, and only a fraction of a dose is expected to reach the central nervous system. Laboratory concentrations therefore sit well above levels achieved systemically, a gap that complicates translation from bench findings to clinical claims.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
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。
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilized solid from research suppliers |
| Solubility | Freely soluble in water | Also dissolves in aqueous buffers; solutions are used fresh |
| Typical storage temperature | -20 °C for lyophilized powder | Short-term transport at 2-8 °C is common |
| Common analytical method | Reverse-phase HPLC | Paired with mass spectrometry for identity confirmation |
| Common synonyms | ACTH(4-10) analogue; MEHFPGP | N-terminal methionine retained in the chain |
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.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
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。
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.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
== Production == After removal from the horse, the hide is measured from the root of the tail 18 inches (460 mm) forward on the backbone. The hide is cut at right angles to the backbone and the resulting pieces termed a "front" (the forward part) and the "butt". The term cordovan leather applies to the product of both the tanned fronts and tanned butts, but is especially used in connection with the term galoshes, meaning the vamps or boot-fronts cut from the shell of the butt. After being tanned, leather from the "front" is typically used in the fabrication of gloves, or blackened, to be used in the tops of shoes. The "butt", after tanning, is passed through a splitting-machine which removes the grain, or hair side, revealing what is termed the "shell". The close fibers of the shell result in a smooth and pliable material.
Debridement, referring to the removal of dead tissue by surgical or non-surgical means, is the standard therapy for necrosis. Depending on the severity of the necrosis, this may range from removal of small patches of skin to complete amputation of affected limbs or organs. Chemical removal of necrotic tissue is another option in which enzymatic debriding agents, categorised as proteolytic, fibrinolytic or collagenases, are used to target the various components of dead tissue. In select cases, special maggot therapy using Lucilia sericata larvae has been employed to remove necrotic tissue and infection. In the case of ischemia, which includes myocardial infarction, the restriction of blood supply to tissues causes hypoxia and the creation of reactive oxygen species (ROS) that react with, and damage proteins and membranes. Antioxidant treatments can be applied to scavenge the ROS. Wounds caused by physical agents, including physical trauma and chemical burns, can be treated with antibiotics and anti-inflammatory drugs to prevent bacterial infection and inflammation. Keeping the wound clean from infection also prevents necrosis. Chemical and toxic agents (e.g. pharmaceutical drugs, acids, bases) react with the skin leading to skin loss and eventually necrosis. Treatment involves identification and discontinuation of the harmful agent, followed by treatment of the wound, including prevention of infection and possibly the use of immunosuppressive therapies such as anti-inflammatory drugs or immunosuppressants.
(Stone, 2017) Depression is a major problem globally, affecting an estimated 4.4 percent of the world population in 2017, roughly equivalent to 300 million people. The depression is multifactorial and has been on the increase due to societal pressure, genetic association and increase in use of drugs (Zhang et al. 2016). incorporation of nursing in management of depression may seem important in that nursing hold a pivotal role in health care delivery where they are they are the health practitioners that have been trained to be versatile from clinical to psychological care Their incorporation shared decision making in treating depression may be important as nurses are known to have the best interpersonal relationship with the patients thus a better collaborative model can be achieved due to this fact (Williams et al. 2016). With this in mind, the nurses may serve to administer drugs in management, prepare and maintain the patient's records, interaction with other care staff to achieve optimum care, and organizing therapy sessions (Lu et al. 2019). Kathleen Walsh, 2017, recognizes that Dr. Velligan stated that SDM is of importance in demonstrating patient preferences in decision making when there is no clear approach to treatment. In addition, numerous tools can be used to make the decision making the process easier these include the Controlled Preferences Scale that informs clinicians on how to actively involve patients.
Sources: en.wikipedia.org
== Research == Animal models have shown that low-dose methamphetamine improves cognitive and behavioural functioning following TBI (traumatic brain injury). This is in contrast to high, repeated doses which cause neurotoxicity. These models demonstrate that low-dose methamphetamine increases neurogenesis and reduces apoptosis in the dentate gyrus of the hippocampus following TBI. It has also been found that TBI patients testing positive for methamphetamine at the time of emergency department admission have lower rates of mortality. It has been suggested, based on animal research, that calcitriol, the active metabolite of vitamin D, can provide significant protection against the DA- and 5-HT-depleting effects of neurotoxic doses of methamphetamine. Protection against methamphetamine-induced neurotoxicity has also been observed following administration of ascorbic acid (vitamin C), cobalamin (vitamin B12), and vitamin E.
25 July What would become known as the "Nixon Doctrine" was outlined for the first time in an informal press conference with reporters who had accompanied Nixon to Guam during his Asian tour. In remarks later published, but given at the time "for attribution but not direct quotation", Nixon said, "I believe that the time has come when the United States, in our relations with all of our Asian friends, be quite emphatic on two points: One, that we will keep our treaty commitments... but, two, that as far as the problems of internal security are concerned, as far as the problems of military defense... that the United States is going to encourage and has a right to expect that... the responsibility for it taken by, the Asian nations themselves."
== Technology == Dr. Werner Baumgartner was responsible for founding Psychemedics and spearheading its initial research. A nationally recognized expert on drug testing through hair samples, Dr. Baumgartner gained acclaim by procuring some strands of hair from the 19th-century poet John Keats. Despite the age of the hair, Baumgartner was able to detect that the poet, who died at the age of 26 from tuberculosis, had been taking an increasing amount of opium before his death, most likely used in painkillers. Dr. Baumgartner's find created a minor sensation, enough to warrant a mention in a 1985 Time magazine cover story about drugs in the workplace. After years of research proved that drugs deposited in the hair can be accurately measured, the company was formed in 1987 and pioneered the use of hair testing in commercial markets including banks, manufacturers, retailers, mining operations, hotels and casinos. The technology capitalizes on the way the body metabolizes ingested drugs as they flow through the blood stream and deposit in the cortex of the hair. Hair is stable and the deposits are permanently embedded in the hair, so hair acts like a tape recorder — “recording” drug deposits in proportion to use over time as drugs are deposited in proportion to use. Hair grows at approximately the rate of ½ an inch per month and takes about 5 days to grow out past the external layer of skin. Psychemedics’ standard test uses a 1 ½ inch sample of head hair, which provides an approximate 3 month history of drug use. Body hair can also be collected if head hair is not available.
==== Rare side effects ==== Infrequent adverse reactions in patients taking opioids for pain relief include: dose-related respiratory depression (especially with more potent opioids), confusion, hallucinations, delirium, urticaria, hypothermia, bradycardia/tachycardia, orthostatic hypotension, dizziness, headache, urinary retention, ureteric or biliary spasm, muscle rigidity, myoclonus (with high doses), and flushing (due to histamine release, except fentanyl and remifentanil). Both therapeutic and chronic use of opioids can compromise the function of the immune system. Opioids decrease the proliferation of macrophage progenitor cells and lymphocytes, and affect cell differentiation (Roy & Loh, 1996). Opioids may also inhibit leukocyte migration. However the relevance of this in the context of pain relief is not known.
Sources: en.wikipedia.org
== Signs and symptoms == Signs and symptoms of TIA are widely variable and can mimic other neurologic conditions, making the clinical context and physical exam crucial in ruling in or out the diagnosis. The most common presenting symptoms of TIA are focal neurologic deficits, which can include, but are not limited to:
For women, the Population Reference Intake is 13 mg/day for ages 15–17 years, 16 mg/day for women ages 18 and up who are premenopausal, and 11 mg/day postmenopausal; for pregnancy and lactation, 16 mg/day. For men, the Population Reference Intake is 11 mg/day for ages 15 and older. For children ages 1 to 14, the Population Reference Intake increases from 7 to 11 mg/day. The Population Reference Intakes are higher than the US RDAs, with the exception of pregnancy.
The US and USSR began discussions on the peaceful uses of space as early as 1958, presenting issues for debate to the United Nations, which created a Committee on the Peaceful Uses of Outer Space in 1959. On May 10, 1962, Vice President Johnson addressed the Second National Conference on the Peaceful Uses of Space revealing that the United States and the USSR both supported a resolution passed by the Political Committee of the UN General Assembly in December 1962, which not only urged member nations to "extend the rules of international law to outer space," but to also cooperate in its exploration. Following the passing of this resolution, Kennedy commenced his communications proposing a cooperative American and Soviet space program. In 1963, the Partial Nuclear Test Ban Treaty was signed by more than 100 signatories, including both the United States and the Soviet Union. This treaty followed the US test of a nuclear bomb detonated in outer space the year earlier called Starfish Prime. The UN ultimately created a Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, which was signed by the United States, the USSR, and the United Kingdom on January 27, 1967, and came into force the following October 10.
Sources: en.wikipedia.org
It consists mainly of animal experiments and small clinical reports, with much of the clinical material published in Russian-language journals. Large independent trials are scarce. Separating reliable effects from chance findings is consequently difficult.
A fraction of an intranasal dose is thought to reach the central nervous system, and this route is favoured partly for that reason. The proportion is not well characterized. Direct measurement in humans remains difficult with current methods.
Raised BDNF and NGF expression has been reported across several animal studies, which makes the signal fairly consistent. Whether the same change occurs in humans at usable doses is not established. It is best treated as a working hypothesis rather than a confirmed clinical mechanism.
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。