A practical reference on reversed-phase HPLC: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
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。
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。
| Property | Value | Notes |
|---|---|---|
| Primary research models | Rodent studies | Largest share of published data |
| Reported markers | BDNF and NGF expression | Measured mainly in animal tissue |
| Common administration | Intranasal | Matches the registered formulation |
| Blood residence time | Minutes | Rapid enzymatic degradation |
| Evidence quality | Small trials, limited replication | Noted repeatedly in reviews |
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
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.
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.
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.
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
== Informatics == A major challenge for lipidomics, in particular for MS-based approaches, lies in the computational and bioinformatic demands of handling the large amount of data that arise at various stages along the chain of information acquisition and processing. Chromatographic and MS data collection requires substantial efforts in spectral alignment and statistical evaluation of fluctuations in signal intensities. Such variations have a multitude of origins, including biological variations, sample handling and analytical accuracy. As a consequence several replicates are normally required for reliable determination of lipid levels in complex mixtures. Within the last few years, a number of software packages have been developed by various companies and research groups to analyze data generated by MS profiling of metabolites, including lipids. The data processing for differential profiling usually proceed through several stages, including input file manipulation, spectral filtering, peak detection, chromatographic alignment, normalization, visualization, and data export. An example of metabolic profiling software is the freely-available Java-based Mzmine application. Another is Metabolon, Inc's commercial applications for metabolomic analysis using proprietary software. Recently MS-DIAL 4 software was integrated with a comprehensive lipidome atlas with retention time, collision cross-section and tandem mass spectrometry information for 117 lipid subclasses and 8,051 lipids.
The downfall of the overall cyclol model generally led to a rejection of its elements; one notable exception was J. D. Bernal's short-lived acceptance of the Langmuir-Wrinch hypothesis that protein folding is driven by hydrophobic association. Nevertheless, cyclol bonds were identified in small, naturally occurring cyclic peptides in the 1950s. Clarification of the modern terminology is appropriate. The classic cyclol reaction is the addition of the NH amine of a peptide group to the C=O carbonyl group of another; the resulting compound is now called an azacyclol. By analogy, an oxacyclol is formed when an OH hydroxyl group is added to a peptidyl carbonyl group. Likewise, a thiacyclol is formed by adding an SH thiol moiety to a peptidyl carbonyl group. The oxacyclol alkaloid ergotamine from the fungus Claviceps purpurea was the first identified cyclol. The cyclic depsipeptide serratamolide is also formed by an oxacyclol reaction. Chemically analogous cyclic thiacyclols have also been obtained. Classic azacyclols have been observed in small molecules and tripeptides. Peptides are naturally produced from the reversion of azacylols, a key prediction of the cyclol model. Hundreds of cyclol molecules have now been identified, despite Linus Pauling's calculation that such molecules should not exist because of their unfavorably high energy. After a long hiatus during which she worked mainly on the mathematics of X-ray crystallography, Wrinch responded to these discoveries with renewed enthusiasm for the cyclol model and its relevance in biochemistry.
But it was later discovered that this is only true for four of the fifteen lanthanides (lanthanum, cerium, gadolinium, and lutetium), and that the other lanthanide atoms do not have a d-electron. In particular, ytterbium completes the 4f shell and thus Soviet physicists Lev Landau and Evgeny Lifshitz noted in 1948 that lutetium is correctly regarded as a d-block rather than an f-block element; that bulk lanthanum is an f-metal was first suggested by Jun Kondō in 1963, on the grounds of its low-temperature superconductivity. This clarified the importance of looking at low-lying excited states of atoms that can play a role in chemical environments when classifying elements by block and positioning them on the table. Many authors subsequently rediscovered this correction based on physical, chemical, and electronic concerns and applied it to all the relevant elements, thus making group 3 contain scandium, yttrium, lutetium, and lawrencium and having lanthanum through ytterbium and actinium through nobelium as the f-block rows: this corrected version achieves consistency with the Madelung rule and vindicates Bassett, Werner, and Bury's initial chemical placement. In 1988, IUPAC released a report supporting this composition of group 3, a decision that was reaffirmed in 2021.
The most expensive process was to preserve the body by dehydration and protect against pests, such as insects. Almost all of the actions Herodotus described served one of these two functions. First, the brain was removed from the cranium through the nose; the gray matter was discarded. Modern mummy excavations have shown that instead of an iron hook inserted through the nose as Herodotus claims, a rod was used to liquefy the brain via the cranium, which then drained out the nose by gravity. The embalmers then rinsed the skull with certain drugs that mostly cleared any residue of brain tissue and also had the effect of killing bacteria. Next, the embalmers made an incision along the flank with a sharp blade fashioned from an Ethiopian stone and removed the contents of the abdomen. Herodotus does not discuss the separate preservation of these organs and their placement either in special jars or back in the cavity, a process that was part of the most expensive embalming, according to archaeological evidence. The abdominal cavity was then rinsed with palm wine and an infusion of crushed, fragrant herbs and spices; the cavity was then filled with spices including myrrh, cassia, and, Herodotus notes, "every other sort of spice except frankincense", also to preserve the person. The body was further dehydrated by placing it in natron, a naturally occurring salt, for 70 days. Herodotus insists that the body did not stay in the natron longer than 70 days.
Central obesity: waist ≥94 cm (37 in) men; ≥80 cm (31.5 in) women Dyslipidaemia: TG ≥2.0 mmol/L (177 mg/dL) and/or HDL-C <1.0 mmol/L (38.61 mg/dL) or treated for dyslipidaemia Blood pressure ≥140/90 mmHg or antihypertensive medication Fasting plasma glucose ≥6.1 mmol/L (110 mg/dL)
Sources: en.wikipedia.org
Hypoprolactinemia, or serum prolactin deficiency, is associated with ovarian dysfunction in women, and arteriogenic erectile dysfunction, premature ejaculation, oligozoospermia, asthenospermia, hypofunction of seminal vesicles and hypoandrogenism in men. In one study, normal sperm characteristics were restored when prolactin levels were raised to normal values in hypoprolactinemic men. Hypoprolactinemia can result from hypopituitarism, excessive dopaminergic action in the tuberoinfundibular pathway and ingestion of D2 receptor agonists such as bromocriptine. Dextroamphetamine has been shown to reduce serum prolactin, presumably due to its dopaminergic effects, indirectly increasing activation of dopamine D2 receptors with data showing intravenous dextroamphetamine at doses between 7.5 mg to 15 mg reducing serum prolactin by 27-32% and 30-37%, respectively, while an oral dose of 20 mg led to a sustained 40% reduction of serum prolactin in postpartum women.
In the US, even though sildenafil is available only by prescription from a doctor, it was advertised directly to consumers on TV (famously being endorsed by former United States Senator Bob Dole and football star Pelé). Numerous sites on the Internet offer Viagra for sale after an "online consultation", often a simple web questionnaire. Viagra and other products for sexual dysfunction, termed sexuopharmaceuticals, proliferated new types of specialised marketing for such products. Viagra and similar prescription pharmaceuticals were promoted by images in media to the extent of becoming a cultural icon, at the time a relatively new phenomenon known to be permitted only in the United States and New Zealand and which is believed to have significantly contributed to norms regarding male sexuality. One author notes that although the effect of Viagra is only limited to penile blood vessels, advertisements routinely use imagery of couples hugging, smiling and dancing, with the author claiming that pharmaceutical companies were deceptive in the use of such advertisements. In 2000, Viagra sales accounted for 92% of the global market for prescribed erectile dysfunction pills. By 2007, Viagra's global share had plunged to about 50% due to several factors, including the entry of Cialis and Levitra, along with several counterfeits and clones, and reports of vision loss in people taking PDE5 inhibitors. In 2008, the FDA forced Pfizer to remove Viva Cruiser, an advergame for Viagra, from appearing on Forbes, after the game failed to disclose risk information about the drug.
An improvement on the loose-coupled train is the "Instanter" coupling, in which the middle link of a three-link chain is specially triangular shaped, so that when lying "prone" it provides enough slack to make coupling possible, but when the middle link is rotated 90 degrees, the length of the chain is effectively shortened, reducing the amount of slack without the need to wind a screw. The closeness of the coupling allows the use of inter-vehicle pipes for train brakes. Three-link and Instanter couplings can be operated entirely from the side of the wagons, using a shunter's pole, which has a hook on the end, and is safer when shunting is being done. Similarly, the screw-adjustable coupler can be connected by a shunter's pole once it has been unscrewed. Ordinary three-link couplings have been superseded by instanter, screw or buck-eye couplers in UK freight trains today.
Atha sold coffee in the California area, but proposed to James Folger II that he open and manage a Folgers Coffee plant in Texas. The company grew exponentially after Atha opened the Texas plant. Under the mid-20th century leadership of Peter Folger, the brand became one of the principal coffee concerns in North America. In 1960, the construction of a Folger Coffee Company plant in New Orleans was started due to new shipping routes from Central America. Procter & Gamble acquired Folger's in 1963 and removed the apostrophe from its name. On August 9, 1969, company heiress Abigail Folger was stabbed to death in Los Angeles as part of the Manson Family's Tate–LaBianca murders. P&G announced in January 2008 that Folgers would be spun off into a separate Cincinnati-based company but reversed itself that June and announced Folgers would be acquired by the end of 2008 by The J.M. Smucker Company. Utilizing a rare financial technique called a Reverse Morris Trust, Smucker purchased Folgers in November 2008 and made it a subsidiary.
=== EC 2.7.11: Protein-serine/threonine kinases === EC 2.7.11.1: non-specific serine/threonine protein kinase EC 2.7.11.2: [pyruvate dehydrogenase (acetyl-transferring)] kinase EC 2.7.11.3: dephospho-(reductase kinase) kinase EC 2.7.11.4: (3-methyl-2-oxobutanoate dehydrogenase (acetyl-transferring)) kinase EC 2.7.11.5: [isocitrate dehydrogenase (NADP+)] kinase EC 2.7.11.6: [tyrosine 3-monooxygenase] kinase EC 2.7.11.7: myosin-heavy-chain kinase EC 2.7.11.8: Fas-activated serine/threonine kinase EC 2.7.11.9: Goodpasture-antigen-binding protein kinase EC 2.7.11.10: IkB kinase EC 2.7.11.11: cAMP-dependent protein kinase EC 2.7.11.12: cGMP-dependent protein kinase EC 2.7.11.13: protein kinase C EC 2.7.11.14: rhodopsin kinase EC 2.7.11.15: β-adrenergic-receptor kinase EC 2.7.11.16: G-protein-coupled receptor kinase EC 2.7.11.17: Ca2+/calmodulin-dependent protein kinase EC 2.7.11.18: myosin-light-chain kinase EC 2.7.11.19: phosphorylase kinase EC 2.7.11.20: elongation factor 2 kinase EC 2.7.11.21: polo kinase EC 2.7.11.22: cyclin-dependent kinase EC 2.7.11.23: [RNA-polymerase]-subunit kinase EC 2.7.11.24: mitogen-activated protein kinase EC 2.7.11.25: mitogen-activated protein kinase kinase kinase EC 2.7.11.26: tau-protein kinase EC 2.7.11.27: [acetyl-CoA carboxylase] kinase EC 2.7.11.28: tropomyosin kinase EC 2.7.11.29: low-density-lipoprotein receptor kinase EC 2.7.11.30: receptor protein serine/threonine kinase EC 2.7.11.31: [hydroxymethylglutaryl-CoA reductase (NADPH)] kinase EC 2.7.11.32: [pyruvate, phosphate dikinase] kinase EC 2.7.11.33: [pyruvate, water dikinase] kinase
Sources: en.wikipedia.org
Protein nuclear magnetic resonance is performed on aqueous samples of highly purified protein. Usually, the sample consists of between 300 and 600 microlitres with a protein concentration in the range 0.1 – 3 millimolar. The source of the protein can be either natural or produced in a production system using recombinant DNA techniques through genetic engineering. Recombinantly expressed proteins are usually easier to produce in sufficient quantity, and this method makes isotopic labeling possible. The purified protein is usually dissolved in a buffer solution and adjusted to the desired solvent conditions. The NMR sample is prepared in a thin-walled glass tube.
A work of non-fiction Echoes of Life: What Fossil Molecules Reveal about Earth History, published in 2009, provides an up-to-date survey of the interdisciplinary field of organic geochemistry, using the history of discovery, from early experiments in the 1930s to modern areas of research, to make the material accessible to students and scientists in different fields.
For services to the Arts and to the community in Southend-on-Sea, Essex. Dr. Alasdair Cunningham Bruce. Boston Spa Renewed Programme Manager. For services to Libraries. Christopher John Paul Bryant. Director of Tournaments and Events, Football Association. For services to Sport. Jennifer Sheridan Bryer. Teacher, Pony Club. For services to Horse Riding. Peter George Buchan. Managing Director, Shipping, Nuclear Transport Solutions. For services to the Nuclear Industry and to Young People. Khumi Tonsing Burton, JP, DL. For services to the community in Manchester and Cheshire. Ronald Butler. Policy Adviser, Department for Work and Pensions. For services to Disadvantaged People. Carrie Byrom. Director, Stable Lives. For services to Mental Health and the community in North West England. David Corrie Calvert. President, Langholm Town Band. For services to the community in Langholm, Dumfries. Carl Campbell. Founder and Artistic Director, CCDC7. For services to African Caribbean Dance Education and Culture. Catriona Yvonne Fiona Campbell. UK&I Chief Technology and Innovation Officer, EY. For services to Technology and Innovation. George Alan Carney. Executive Officer, Department for Education. For Public Service. Professor Kathryn Janice Carruthers. Professor of French Linguistics, Queen's University Belfast. For services to Modern Languages. Kathryn Melanie Keele Caton. Founder and Managing Director, Brighton Gin. For services to Trade and to the community in Brighton. Amanda Chadwick. Founder and Trustee, Pyjama Fairies. For services to Children in Hospital. Edward Kay Kiu Chan.
The Doctor of Clinical Laboratory Science (DCLS) is a professional degree in clinical laboratory science in the United States for medical laboratory scientists. The DCLS is board eligible and qualifies as a CLIA high complexity laboratory director (HCLD). Doctors of Clinical Laboratory Science may conduct research or serve on healthcare teams. DCLS work closely with physicians, catching pre- analytical, analytical, and post-analytical test and interpretation errors in order to ensure optimal patient care outcomes. Doctors of Clinical Laboratory Science complete a residency at the end of their training. There are four programs:
The mature mRNA finds its way to a ribosome, where it gets translated. In prokaryotic cells, which have no nuclear compartment, the processes of transcription and translation may be linked together without clear separation. In eukaryotic cells, the site of transcription (the cell nucleus) is usually separated from the site of translation (the cytoplasm), so the mRNA must be transported out of the nucleus into the cytoplasm, where it can be bound by ribosomes. The ribosome reads the mRNA triplet codons, usually beginning with an AUG (adenine−uracil−guanine), or initiator methionine codon downstream of the ribosome binding site. Complexes of initiation factors and elongation factors bring aminoacylated transfer RNAs (tRNAs) into the ribosome-mRNA complex, matching the codon in the mRNA to the anti-codon on the tRNA. Each tRNA bears the appropriate amino acid residue to add to the polypeptide chain being synthesised. As the amino acids get linked into the growing peptide chain, the chain begins folding into the correct conformation. Translation ends with a stop codon which may be a UAA, UGA, or UAG triplet. The mRNA does not contain all the information for specifying the nature of the mature protein. The nascent polypeptide chain released from the ribosome commonly requires additional processing before the final product emerges. For one thing, the correct folding process is complex and vitally important. For most proteins it requires other chaperone proteins to control the form of the product.
Sources: en.wikipedia.org
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.
The compound is registered as a medicine in Russia, so clinical work has concentrated there. Trials elsewhere are few and generally small. This geographic concentration is a recognized limitation in evidence reviews.
Some fraction may reach the central nervous system through olfactory pathways, and this is often cited as the rationale for the nasal route. The size of that fraction in humans is not well quantified. Blood concentrations after nasal dosing are low, which complicates measurement.
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。