If you have been reading about counterion 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 2025-09-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Identity and purity are commonly assessed by reversed-phase high-performance liquid chromatography, with ultraviolet detection near 214 nanometers for the peptide backbone. Mass spectrometry, either electrospray or matrix-assisted laser desorption, confirms molecular mass and detects truncation or modification products. Amino acid analysis can verify composition. Because the sequence contains no strongly absorbing aromatic residue apart from phenylalanine, detection wavelengths are chosen carefully. Purity values above 95 percent are typical for research-grade material.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analogue of the ACTH(4-10) fragment |
| Amino acid sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Single-letter form MEHFPGP |
| Molecular formula | C37H51N9O10S | Free peptide, nominal mass near 814 Da |
| First registration | 1994, Russia | Nasal formulation for neurological indications |
| Typical purity grade | 95% or higher by HPLC | Research material; higher grades used as reference standards |
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
Scientific literature on semax is unevenly distributed. A substantial share of published work originates from a small number of laboratories in Russia, while independent replication elsewhere is limited. Human data consist mostly of small trials with short follow-up, and several reported outcomes rely on subjective rating scales. Questions about how much intact peptide reaches the central nervous system after nasal administration, and how long it persists there, are still unresolved. The compound is best described as an active research subject rather than a settled pharmacological agent.
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.
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.
The Boer government later handed the men over to the British for trial and the British prisoners were returned to London. A few days after the raid, the Kaiser of Germany sent a telegram (the "Kruger telegram") congratulating President Kruger and the Transvaal government on their success "without the help of friendly powers", alluding to potential support by Germany. When this was disclosed in the British press, it raised a storm of anti-German feeling. Dr. Jameson was lionised by the press and London society, inflamed by anti-Boer and anti-German feeling and in a frenzy of jingoism. Jameson was sentenced to 15 months for leading the raid, which he served in Holloway Prison, while his second-in-command Willoughby was sentenced to 10 months.. The Transvaal government was paid almost £1 million in compensation by the British South Africa Company. For conspiring with Jameson, the members of the Reform Committee (Transvaal), including Colonel Frank Rhodes and John Hays Hammond, were jailed in deplorable conditions, found guilty of high treason, and sentenced to death by hanging. This sentence was later commuted to 15 years' imprisonment, and in June 1896, all surviving members of the committee were released on payment of stiff fines. As further punishment for his support of Jameson, the highly decorated Col. Rhodes was placed on the retired list by the British Army and barred from active involvement in army business.
pinocytosis A form of endocytosis in which liquid and suspended solids from the extracellular environment are captured in inward invaginations of the cell membrane which then "bud off" into enclosed vesicles in the cytoplasm. The contents of these vesicles are then passed to organelles such as endosomes by fusion of the vesicular and organellar membranes. Pinocytosis is the predominant form of endocytosis occurring in most cells, such that the term is often used interchangeably with endocytosis as a whole.
== Structure and bonding == Most organomercury compounds feature diamagnetic Hg(II) and adopt a linear C−Hg−X structure. Indeed, no organic derivatives of Hg2+2 are known, as Hg2+2 requires electronegative substituents for condensed-phase stability. Hg(II) derivatives are neither Lewis basic or Lewis acidic. They are stable to oxygen and water, indicating the low polarity of the Hg−C bond. The structure of "mercurocene" is instructive. When made in the 1950s, it was too sensitive for structural determination. Later analysis determined that the products have the mercury σ-bonded to just one carbon of each ring, rather than a metallocene with the metal bonded to the rings' π systems.
One person was killed in a Russian attack in Kherson Oblast. Russian-installed officials in Luhansk Oblast claimed that a gas pipeline was damaged by a missile attack in Pervomaisk. The HUR claimed that it had destroyed two Russian KS-701 Tunets patrol boats and damaged two other vessels in Vuzka Bay in Chornomorske, Crimea, using naval drones. SBU drones destroyed a Russian Nebo-SVU radar system in Armiansk, Crimea. President Biden gave Ukraine permission to use weapons provided by the U.S. to attack Russian units in Russian soil in the vicinity of Kharkiv. Germany announced another military aid package for Ukraine worth €500 million ($540 million) that would include artillery, air defence and drones.
== Specialty areas == Many medical laboratory scientists are generalists, skilled in most areas of the clinical laboratory. However, some are specialists, qualified by unique undergraduate education or additional training to perform more complex analyses than usual within a specific field. Specialties include clinical biochemistry, hematology, coagulation, microbiology, bacteriology, toxicology, virology, parasitology, mycology, immunology, immunohematology (blood bank), histopathology, histocompatibility, cytopathology, genetics, cytogenetics, electron microscopy, and IVF labs. Medical technologists specialty may use additional credentials, such as "SBB" (specialist in blood banking), "SM" (specialist in microbiology), "SC" (specialist in chemistry), or "SH" (specialist in hematology) from the American Society for Clinical Pathology (ASCP). These additional notations may be appended to the base credential, for example, "MLS (ASCP), SBB (ASCP)". Additional information can be found in the ASCP Procedures for Examination & Certification. Andrology laboratory scientist (such as those working for a sperm bank), embryology laboratory scientist, and molecular diagnostics technologist certifications are provided by the American Association of Bioanalysts; those with the certifications are classified as ALS (AAB), ELS (AAB), and MDxT (AAB), respectively.
Sources: en.wikipedia.org
Subsequent addition of three 5-carbon IPP units to a single 5-carbon DMAPP unit generates the 20-carbon central precursor, geranylgeranyl diphosphate (GGPP). Bicyclization of GGPP by the class II diterpene synthase, ent-clerodienyl diphosphate synthase (SdCPS2), produces a labdanyl diphosphate carbocation, which is subsequently rearranged through a sequence of 1,2-hydride and methyl shifts to form the ent-clerodienyl diphosphate intermediate. SdCPS2 catalyzes the first committed reaction in the biosynthesis of salvinorin A by producing its characteristic clerodane scaffold. A series of oxygenation, acylation and methylation reactions is then required to complete the biosynthesis of salvinorin A.
Nalmefene acts as an inverse agonist of the μ-opioid receptor (MOR) (KiTooltip Inhibitor constant = 0.24 nM) and as a weak partial agonist (Ki = 0.083 nM; Emax = 20–30%) of the κ-opioid receptor (KOR), with similar binding for these two receptors but a several-fold preference for the KOR. In another study however, nalmefene had approximately equal affinity for the MOR and KOR. In vivo evidence indicative of KOR activation, such as elevation of serum prolactin levels due to dopamine suppression and increased hypothalamic–pituitary–adrenal axis activation via enhanced adrenocorticotropic hormone and cortisol secretion, has been observed in humans and animals. Side effects typical of KOR activation such as hallucinations and dissociation have also been observed with nalmefene in human studies. It is thought that nalmefene activation of KOR may produce dysphoria and anxiety. In addition to MOR and KOR binding, nalmefene also possesses some, albeit far lower affinity for the δ-opioid receptor (DOR) (Ki = 16 nM), where it behaves as an antagonist. Nalmefene is structurally related to naltrexone and differs from it by substitution of the ketone group at the C6 position of naltrexone with a methylene group (CH2). It binds to the MOR with similar affinity relative to naltrexone, but binds "somewhat more avidly" to the KOR and DOR in comparison. Nalmefene with a single 1 mg dose by intravenous injection has been found to produce brain MOR blockade of 99% at 5 minutes, 90% at 2 hours, 33% at 4 hours, and 10% at 8 hours.
For weight loss to be permanent, changes in diet and lifestyle must be permanent as well. There is evidence that counseling or exercise alone do not result in weight loss, whereas dieting alone results in meaningful long-term weight loss, and a combination of dieting and exercise provides the best results. Meal replacements, orlistat, a very-low-calorie diet, and primary care intensive medical interventions can also support meaningful weight loss.
== History == The disease was first noted by German pathologist Karl Theodor Fahr in 1930. A less common name for the condition is Chavany-Brunhes syndrome and Fritsche's syndrome, the former named after Jacques Brunhes, Jean Alfred Émile Chavany, while the later named after R. Fritsche. Fewer than 20 families had been reported in the literature up to 1997.
Sources: en.wikipedia.org
The developing lung is particularly vulnerable to changes in the levels of vitamin A. Vitamin A deficiency has been linked to changes in the epithelial lining of the lung and in the lung parenchyma. This can disrupt the normal physiology of the lung and predispose to respiratory diseases. Severe nutritional deficiency in vitamin A results in a reduction in the formation of the alveolar walls (septa) and to notable changes in the respiratory epithelium; alterations are noted in the extracellular matrix and in the protein content of the basement membrane. The extracellular matrix maintains lung elasticity; the basement membrane is associated with alveolar epithelium and is important in the blood-air barrier. The deficiency is associated with functional defects and disease states. Vitamin A is crucial in the development of the alveoli which continues for several years after birth.
In the Hellenistic world the art of alchemy first proliferated, mingling magic and occultism into the study of natural substances with the ultimate goal of transmuting elements into gold and discovering the elixir of eternal life. Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. Alchemy continued to be developed and practised throughout the Arab world after the Muslim conquests, and from there, and from the Byzantine remnants, diffused into medieval and Renaissance Europe through Latin translations. The Arabic works attributed to Jabir ibn Hayyan introduced a systematic classification of chemical substances, and provided instructions for deriving an inorganic compound (sal ammoniac or ammonium chloride) from organic substances (such as plants, blood, and hair) by chemical means. Some Arabic Jabirian works (e.g., the "Book of Mercy", and the "Book of Seventy") were later translated into Latin under the Latinized name "Geber", and in 13th-century Europe an anonymous writer, usually referred to as pseudo-Geber, started to produce alchemical and metallurgical writings under this name. Later influential Muslim philosophers, such as Abū al-Rayhān al-Bīrūnī and Avicenna disputed the theories of alchemy, particularly the theory of the transmutation of metals.
Xi's foreign policy thoughts are collectively known as Xi Jinping Thought on Diplomacy. Xi has promoted major-country diplomacy, stating that China is already a "big power" and breaking away from previous Chinese leaders who had a more precautious diplomacy. Diplomats under Xi have adopted a hawkish foreign policy posture called "wolf warrior diplomacy" starting from the late 2010s; this form of diplomacy peaked in the early 2020s and declined afterwards. Xi frequently says that the world is seeing "great changes unseen in a century", referring to geopolitical shifts in which the United States is seen as a declining power and in which the rise of populism, economic securitization, and advancing technology create an environment of uncertainty that results in both opportunities and threats for China. In October 2020, he said that "the East is rising and the West is declining", saying that the power of the Western world was in decline as exemplified by their COVID-19 response, and that China was entering a period of opportunity because of this. Xi has frequently alluded to community with a shared future for mankind, which Chinese diplomats have said does not imply an intention to change the international order, but which foreign observers say China wants a new order that puts it more at the centre. During the Xi administration, China seeks to shape international norms and rules in emerging policy areas where China has an advantage as an early participant.
Sources: en.wikipedia.org
Registered medical products are most often 0.1% nasal drops. Research suppliers ship lyophilized powder, usually in milligram quantities, which is dissolved before use. The active peptide is the same in both cases; presentation and excipients differ.
No. The peptide is synthetic, although it is modelled on a fragment of a naturally occurring hormone. ACTH(4-10) is generated when ACTH is cleaved, but the Pro-Gly-Pro extension is not a known endogenous sequence. It is therefore a designed analogue rather than a natural metabolite.
The label reflects reported effects on attention, memory and recovery after neurological injury in regional clinical reports. Those reports are mostly small and have not been widely replicated outside the region. The classification is descriptive and does not imply a single defined mechanism.
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.