tetrapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-08-03. Anything still debated is marked as such rather than presented as settled.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four amino acid residues |
| Residue sequence | Ala-Glu-Asp-Gly | Abbreviated AEDG |
| Approximate mass | 390.35 Da | Monoisotopic, free base form |
| Parent preparation | Epithalamin extract | Derived from pineal tissue |
| Common spelling variants | Epithalon, epithalone, AEDG | Affects literature retrieval |
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
The first elections took place in January 1889 and the county council formally came into being on 1 April 1889. On that day its first official meeting was held at the old Shire Hall on Old Elvet in Durham, the courthouse (built 1811) which had served as the meeting place of the quarter sessions which preceded the county council. The first chairman of the council was John Lloyd Wharton, who was the Conservative Member of Parliament for Ripon (in Yorkshire); he had also been chairman of the Durham Quarter Sessions since 1871. Durham was the first county council to be controlled by the Labour Party, which won the most seats in 1919. In 1974, the county was redesignated as a non-metropolitan county under the Local Government Act 1972. As part of those reforms the county ceded territory in the north-east to the new county of Tyne and Wear and in the south-east to the new county of Cleveland, but gained the former Startforth Rural District covering the part of Teesdale south of the River Tees from the North Riding of Yorkshire, and Darlington was brought back under the county council's control. Until 1974, the lower tier of local government comprised numerous boroughs, urban districts and rural districts. The districts were also reorganised in 1974 into eight non-metropolitan districts: Chester-le-Street, Darlington, Derwentside, Durham, Easington, Sedgefield, Teesdale, and Wear Valley. In 1997, Darlington became a unitary authority, removing it from county council control.
Venous access is any method used to access the bloodstream through the veins, either to administer intravenous therapy such as medication, or fluid, parenteral nutrition, to obtain blood for analysis, or to provide an access point for blood-based treatments such as dialysis or apheresis. Access is most commonly achieved via the placement of a central venous catheter, a Seldinger technique, and guidance tools such as ultrasound and fluoroscopy can also be used to assist with access location.
Tyrosine or its precursor N-acetyl-L-tyrosine are commonly used to purportedly boost levels of dopamine and noradrenaline. Some brands may contain L-dopa (generally as Mucuna pruriens extract), but this is classified as a prescription medicine in many countries. Theanine is often used as an ingredient (sometimes as "green tea extract", though this may alternatively be used to refer to EGCG, which may also be present), to supposedly improve mental and physical performance, and reduce anxiety. Piperine (often as "black pepper extract") is often included possibly to improve absorption of other ingredients, and for its supposed ability to improve muscle recovery. B vitamins are another common ingredient, most commonly vitamin B3 and vitamin B12 in various forms, but also often thiamine (sometimes as sulbutiamine), pantothenic acid (vitamin B5) and folic acid. Carnitine or its precursor acetylcarnitine are sometimes added to the mix for their supposed ability to enhance exercise performance and aid recovery, though evidence for these benefits is weak. Betaine (trimethylglycine) is often used as an ingredient, despite limited evidence for effectiveness in increasing athletic performance. Phenethylamines such as β-phenethylamine, β-methylphenethylamine, deterenol, halostachine, N-methyltyramine, hordenine, or synephrine (sometimes as "bitter orange extract") may be included as thermogenics to aid in weight loss. Higenamine (norcoclaurine) is also often added for its supposed weight loss and mild stimulant properties.
== Paralogs == Escherichia coli (E. coli) expresses two different forms of shikimate dehydrogenase, AroE and YdiB. These two forms are paralogs of each other. The two forms of shikimate dehydrogenase have different primary sequences in different organisms but catalyze the same reactions. There is about 25% similarity between the sequences of AroE and YdiB, but their two structures have similar structures with similar folds. YdiB can utilize NAD or NADP as a cofactor and also reacts with quinic acid. They both have high affinity of their ligands as shown by their similar enzyme (Km) values. Both forms of the enzyme are independently regulated.
Sources: en.wikipedia.org
== Risk factors == The most prominent risk factors for myocardial infarction are older age, actively smoking, high blood pressure, diabetes mellitus, and total cholesterol and high-density lipoprotein levels. Many risk factors of myocardial infarction are shared with coronary artery disease, the primary cause of myocardial infarction, with other risk factors including male sex, low levels of physical activity, a past family history, obesity, and alcohol use. Risk factors for myocardial disease are often included in risk factor stratification scores, such as the Framingham Risk Score. At any given age, men are more at risk than women for the development of cardiovascular disease. High levels of blood cholesterol is a known risk factor, particularly high low-density lipoprotein, low high-density lipoprotein, and high triglycerides. Many risk factors for myocardial infarction are potentially modifiable, with the most important being tobacco smoking (including secondhand smoke). Smoking appears to be the cause of about 36% and obesity the cause of 20% of coronary artery disease. Lack of physical activity has been linked to 7–12% of cases. Less common causes include stress-related causes such as job stress, which accounts for about 3% of cases, and chronic high stress levels.
== Early life and education == Sur did his early schooling at the St. Joseph's Collegiate School, Allahabad. He received a Bachelor of Technology degree in electrical engineering from the Indian Institute of Technology in Kanpur (IIT Kanpur) in 1974, and Master of Science and PhD degrees in electrical engineering in 1975 and 1978, respectively, from Vanderbilt University in Nashville. After postdoctoral research at Stony Brook University, he was appointed to the faculty of Yale University School of Medicine in 1983.
In addition, medicine can be administered through the skin, by ointments or by means of adhesive patch, such as the nicotine patch or iontophoresis. The skin is an important site of transport in many other organisms. Water resistance: The skin acts as a water-resistant barrier so essential nutrients are not washed out of the body.
A 2018 systematic review and network meta-analysis of 50 trials involving 12 different psychosocial interventions for amphetamine, methamphetamine, or cocaine addiction found that combination therapy with both contingency management and community reinforcement approach had the highest efficacy (i.e., abstinence rate) and acceptability (i.e., lowest dropout rate). Other treatment modalities examined in the analysis included monotherapy with contingency management or community reinforcement approach, cognitive behavioral therapy, 12-step programs, non-contingent reward-based therapies, psychodynamic therapy, and other combination therapies involving these. As of December 2019, there is no effective pharmacotherapy for methamphetamine addiction. A systematic review and meta-analysis from 2019 assessed the efficacy of 17 different pharmacotherapies used in randomized controlled trials (RCTs) for amphetamine and methamphetamine addiction; it found only low-strength evidence that methylphenidate might reduce amphetamine or methamphetamine self-administration. There was low-to moderate-strength evidence of no benefit for most of the other medications used in RCTs, which included antidepressants (bupropion, mirtazapine, sertraline), antipsychotics (aripiprazole), anticonvulsants (topiramate, baclofen, gabapentin), naltrexone, varenicline, citicoline, ondansetron, prometa, riluzole, atomoxetine, dextroamphetamine, and modafinil. Medication-Assisted Treatment (MAT) combines FDA-approved medications with behavioral therapies to address substance use disorders.
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Sources: en.wikipedia.org
=== Organic acidemias === Most jurisdictions did not start screening for any of the organic acidemias before tandem mass spectrometry significantly expanded the list of disorders detectable by newborn screening. Quebec has run a voluntary second-tier screening program since 1971 using urine samples collected at three weeks of age to screen for an expanded list of organic acidemias using a thin layer chromatography method. Newborn screening using tandem mass spectrometry can detect several organic acidemias, including propionic acidemia, methylmalonic acidemia and isovaleric acidemia.
== Research progress == Cannabinoids have multiple therapeutic potentials, including pain, nausea and vomiting, feeding disorder, glaucoma, neurodegeneration, multiple sclerosis, schizophrenia, cancer, epilepsy, stress and anxiety. There are ongoing investigations on the currently marketed drugs, exploring their therapeutic potentials on top of the existing medical uses. For instance, some recent studies have illustrated the antitumor effects of CBD, with the underlying mechanisms being the induction of cell cycle arrest and autophagy, promotion of apoptosis, modulation of angiogenesis, and inhibition of tumor cell migration and invasion. Several clinical reports also showed that CBD can be used to treat cancer. The use of other cannabinoid receptor modulators are also under investigations. Olorinab, Ajulemic acid, NTRX-07 and CNTX-6016 are examples of the new cannabinoid receptors modulators undergoing different stages of clinical trials for their respective therapeutic uses, such as treating Alzheimer's disease and diabetic neuropathy.
"Sympathetic skin response versus maximum motor and sensory conduction velocity to detect subclinical neuropathy in non-insulin-dependent diabetics". Acta Neurologica Belgica. 91 (4): 213–22. PMID 1746243. Hilz, Max J.; Stemper, Brigitte; Axelrod, Felicia B. (1 May 1999). "Sympathetic skin response differentiates hereditary sensory autonomic neuropathies III and IV". Neurology. 52 (8): 1652–1657. doi:10.1212/wnl.52.8.1652. PMID 10331694. S2CID 24227146. Tsementzis, S A; Hitchcock, E R (1 April 1985). "The spoon test: a simple bedside test for assessing sudomotor autonomic failure". Journal of Neurology, Neurosurgery & Psychiatry. 48 (4): 378–380. doi:10.1136/jnnp.48.4.378. PMC 1028306. PMID 3998743. Khurana, Ramesh K.; Russell, Colin (April 2017). "The spoon test: a valid and reliable bedside test to assess sudomotor function". Clinical Autonomic Research. 27 (2): 91–95. doi:10.1007/s10286-017-0401-2. PMID 28188384. S2CID 8755293.
Bilberries are non-climacteric berries with a smooth, circular outline at the end opposite the stalk, whereas American blueberries retain persistent sepals there, leaving a rough, star-shaped pattern of five flaps. Bilberries grow singly or in pairs rather than in clusters, as American blueberries do, and American blueberries have more evergreen leaves. Bilberries are dark in colour, and often appear near black with a slight shade of purple.
Acoustic metamaterials, sometimes referred to as sonic or phononic crystals, are architected materials designed to manipulate sound waves or phonons in gases, liquids, and solids. By tailoring effective parameters such as bulk modulus (β), density (ρ), and in some cases chirality, they can be engineered to transmit, trap, or attenuate waves at selected frequencies, functioning as acoustic resonators when local resonances dominate. Within the broader field of mechanical metamaterials, acoustic metamaterials represent the dynamic branch where wave control is the primary goal. Acoustic metamaterials control, direct and manipulate sound in the form of sonic, infrasonic or ultrasonic waves in gases, liquids and solids. As with electromagnetic waves, sonic waves can exhibit negative refraction. Control of sound waves is mostly accomplished through the bulk modulus β, mass density ρ and chirality. The bulk modulus and density are analogs of permittivity and permeability in electromagnetic metamaterials. Related to this is the mechanics of sound wave propagation in a lattice structure. Also materials have mass and intrinsic degrees of stiffness. Together, these form a resonant system and the mechanical (sonic) resonance may be excited by appropriate sonic frequencies (for example audible pulses). Willis materials exhibit additional nonlocal material parameters for elastic-wave manipulation—analogous to the bianisotropic moduli in electromagnetic media—that couple stress with particle velocity and linear momentum with strain, known as Willis couplings. They are named after J. R.
Sources: en.wikipedia.org
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.
No. Epithalamin is a heterogeneous extract containing many peptides, while epitalon is a single synthesised tetrapeptide. Publications sometimes treat findings from the two as equivalent, which is a common source of confusion. Their compositions differ and they are not interchangeable in analytical terms.
Most published work uses cell cultures or rodents because those models are faster and less costly to run. The few human trials that have been reported are small, and several lack control groups or blinding. This restricts what can reasonably be concluded about effects in people.
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.