Everything below concerns AEDG. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-11-29. Numbers and descriptions here follow the published literature rather than marketing material.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Freeze-dried solid |
| Solubility class | Freely soluble in water | Aqueous buffers also suitable |
| Typical storage temperature | Minus 20 degrees Celsius or colder | Desiccated and light protected |
| Typical analytical method | RP-HPLC with UV detection | 214 nm on C18 column |
| Identity confirmation | Electrospray mass spectrometry | Sequence verified separately |
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
=== Based on absorption === Drugs that change intestinal motility may impact the level of other drugs taken. For example, prokinetic agents increase the intestinal motility, which may cause drugs to go through the digestive system too fast, reducing absorption. The pharmacological modification of pH can affect other compounds. Drugs can be present in ionized or non-ionized forms depending on pKa, and neutral compounds are usually better absorbed by membranes. Medication like antacids can increase pH and inhibit the absorption of other drugs such as zalcitabine, tipranavir and amprenavir. The opposite is more common, with, for example, the antacid cimetidine stimulating the absorption of didanosine. Some resources describe that a gap of two to four hours between taking the two drugs is needed to avoid the interaction. Factors such as food with high-fat content may also alter the solubility of drugs and impact its absorption. This is the case for oral anticoagulants and avocado. The formation of non-absorbable complexes may occur also via chelation, when cations can make certain drugs harder to absorb, for example between tetracycline or the fluoroquinolones and dairy products, due to the presence of calcium ions. . Other drugs bind to proteins. Some drugs such as sucralfate bind to proteins, especially if they have a high bioavailability. For this reason its administration is contraindicated in enteral feeding. Some drugs also alter absorption by acting on the P-glycoprotein of the enterocytes.
Non-focal symptoms such as amnesia, confusion, incoordination of limbs, unusual cortical visual symptoms (such as isolated bilateral blindness or bilateral positive visual phenomena), headaches and transient loss of consciousness are usually not associated with TIA, however patient assessment is still needed. Public awareness on the need to seek a medical assessment for these non-focal symptoms is also low, and can result in a delay by patients to seek treatment Symptoms of TIAs can last on the order of minutes to one–two hours, but occasionally may last for a longer period of time. TIA is defined as ischemic events in the brain that last less than 24 hours. Given the variation in duration of symptoms, this definition holds less significance. A pooled study of 808 patients with TIAs from 10 hospitals showed that 60% lasted less than one hour, 71% lasted less than two hours, and 14% lasted greater than six hours. Importantly, patients with symptoms that last more than one hour are more likely to have permanent neurologic damage, making prompt diagnosis and treatment important to maximize recovery.
=== 1990s === In 1990, following the Grace's Grace Energy public offering in 1989, Grace Energy purchased all of the minority shares of its common stock of its Grace Drilling from Panhandle Eastern Corporation, which gave Grace Energy 99.45% ownership of Grace Drilling. In 1992, Grace sold its 21%-percent interest of Grace Cocoa (Grace Cocoa Associates, LP,), for $300 million. Grace Cocoa was classified as a discontinued operation by Grace in 1993, but due to market conditions, the Grace later sold the rest of the company along with its paper drying, polymer, and filtration units in 1996 for over $300 million. In 1995, Albert Costello became the CEO of the company, replacing J. Peter Grace, as well as became the new president, replacing J.P. Bolduc. Costello was the former CEO and chairman of the board at American Cyanamid (1993-1994). Bolduc (CEO from 1993-1995) was considered to have successfully sold off some of the unprofitable noncore businesses and to have expanded some of the successful businesses within the company at that point in time.
In a systematic review of published evidence, the United States Preventive Services Task Force in 2017 concluded that there was uncertainty about the accuracy or clinical utility of all potential screening tools for OSA, and recommended that evidence is insufficient to assess the balance of benefits and harms of screening for OSA in asymptomatic adults. The diagnosis of OSA syndrome is made when the patient shows recurrent episodes of partial or complete collapse of the upper airway during sleep resulting in apneas or hypopneas, respectively. Criteria defining an apnea or a hypopnea vary. The American Academy of Sleep Medicine (AASM) defines apnea as a reduction in airflow of ≥ 90% lasting at least 10 seconds. A hypopnea is defined as a reduction in airflow of ≥ 30% lasting at least 10 seconds and associated with a ≥ 4% decrease in pulse oxygenation, or as a ≥ 30% reduction in airflow lasting at least 10 seconds and associated either with a ≥ 3% decrease in pulse oxygenation or with an arousal. To define the severity of the condition, the Apnea-Hypopnea Index (AHI) or the Respiratory Disturbance Index (RDI) are used. While the AHI measures the mean number of apneas and hypopneas per hour of sleep, the RDI adds to this measure the respiratory effort-related arousals (RERAs). The OSA syndrome is thus diagnosed if the AHI is > 5 episodes per hour and results in daytime sleepiness and fatigue or when the RDI is ≥ 15 independently of the symptoms.
== Genetics == The enzyme is coded by the gene with the symbol MTHFR on chromosome 1 location p36.3 in humans. There are DNA sequence variants (genetic polymorphisms) associated with this gene. In 2000 a report brought the number of polymorphisms up to 24. Two of the most investigated are C677T (rs1801133) and A1298C (rs1801131) single nucleotide polymorphisms (SNPs). While multiple published studies have drawn relationships between these SNPs and a wide variety of diseases, the American College of Medical Genetics has issued an official Practice Guideline recommending against testing or reporting on these two variants, citing "Recent meta-analyses have disproven an association between hyperhomocysteinemia and risk for coronary heart disease and between MTHFR polymorphism status and risk for venous thromboembolism. There is growing evidence that MTHFR polymorphism testing has minimal clinical utility.". However, a more recent study has shown that the presence of the C677T and/or A1298C polymorphisms may have a critical impact on leukemic cell response to MYC-targeting therapies. This study demonstrates that MTHFR deficiency indeed increases leukemic cell resistance to a variety of MYC-targeting pharmacological agents, including BET protein small-molecule inhibitors.
Sources: en.wikipedia.org
The synthesis of fentanyl and its analogues are illustrated in these skeletal diagrams. The synthesis of fentalogs is done by reacting the ring structure as a base, 4-ANPP also called 4-anilino-N-phenethylpiperidine and despropionylfentanyl. 4-ANPP acts as a base because of its two amine nitrogens, the secondary amine acts as a base to react with an organic acid which condenses into an amide. Depending on the organic acid used in the amide condensation, different analogues of fentanyl will be produced. To help align this phenomenon in the eyes of chemists, we have numerated the precursor 4-ANPP with a [0.], and then the reactions synthesizing fentanyl, acetylfentanyl, butyrylfentanyl, and benzoylfentanyl with a [1.], [2.], [3.], and [4.] respectively. To further aid in the chemical pedagogy we have aligned each number with a reaction number -> precursor -> product system that follows the following scheme: EXAMPLE: reaction number -> precursor -> product [compound name] 1 -> α -> a [fentanyl] 2 -> β -> b [acetylfentanyl] 3 -> γ -> c [butyrylfentanyl] 4 -> δ -> d [benzoylfentanyl] Using the above scheme, a chemist can quickly extrapolate the reactions necessary for other fentanyl analogues with more complex organic acids, such as cyclopropryl fentanyl or cyclopentyl fentanyl, or any other fentanyl analogue derived from a reaction of 4-ANPP with a novel organic acid.
gene therapy The insertion of a functional or wild-type gene or part of a gene into an organism (especially a patient) with the intention of correcting a genetic defect, either by direct substitution of the defective gene or by supplementation with a second, functional version.
== Clinical significance == ALT is commonly measured clinically as part of liver function tests and is a component of the AST/ALT ratio. When used in diagnostics, it is almost always measured in international units/liter (IU/L) or μkat. While sources vary on specific reference range values for patients, 0-40 IU/L is the standard reference range for experimental studies.
Bryant Park is a 9.6-acre (3.9 ha), privately managed public park in the New York City borough of Manhattan. It is located between Fifth Avenue and Avenue of the Americas (Sixth Avenue) and between 40th and 42nd Streets in Midtown Manhattan. The eastern half of Bryant Park is occupied by the Main Branch of the New York Public Library. The western half contains a lawn, shaded walkways, and amenities such as a carousel, and is located entirely over an underground structure that houses the library's stacks. The park hosts several events, including a seasonal "Winter Village" with an ice rink and shops during the winter. The first park at the site was opened in 1847 and was called Reservoir Square due to its proximity to the Croton Distributing Reservoir. Reservoir Square contained the New York Crystal Palace, which hosted the Exhibition of the Industry of All Nations in 1853 and burned down in 1858. The square was renamed in 1884 for abolitionist and journalist William Cullen Bryant. The reservoir was demolished in 1900 and the New York Public Library's main branch was built on the site, opening in 1911. Bryant Park was rebuilt in 1933–1934 to a plan by Lusby Simpson. After a period of decline, it was restored in 1988–1992 by landscape architects Hanna/Olin Ltd. and architects Hardy Holzman Pfeiffer Associates, during which the park was rebuilt and the library's stacks were built underneath. Further improvements were made in the late 20th and early 21st centuries.
== Work == Born in Melbourne, Australia, Bottomley earned a BSc in physics from Monash University in Australia in 1974. In 1975, he started his PhD in physics at the University of Nottingham in England, in one of the three original groups that began MRI. In Raymond Andrew's group, alongside that of Peter Mansfield, they built the first MRI system producing radiographic-quality images of the human wrist, and he performed the initial work on RF-field and power deposition in human MRI. Upon completing his PhD in 1978, he went to Johns Hopkins University in Baltimore in the USA to adapt MRI methods for spatially localizing MRS signals, initially using surface coils to demonstrate localized metabolite depletion and reversal in regional myocardial ischemia in vivo. In 1980, Paul joined the GE Research Center in Schenectady NY. Together with William A. Edelstein and others, this group began GE's entry into MRI technology. They ordered the biggest magnet available at the time – a 1.5 tesla system – and built the first high-field whole-body MRI/MRS scanner, overcoming problems of coil design, RF penetration and signal-to-noise concerns. The results translated into the highly successful 1.5 tesla clinical MRI products of which there are well over 20,000 systems today, representing 60-70% of all systems. Using a combination of switched MRI localizing magnetic field gradients with MRS acquisition, Paul and his colleagues performed the first noninvasive localized MRS of the human heart and brain.
Sources: en.wikipedia.org
Differential scanning calorimetry (DSC) is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and a reference is measured as a function of temperature. Both the sample and reference are maintained at nearly the same temperature throughout the experiment. Generally, the temperature program for a DSC analysis is designed such that the sample holder temperature increases linearly as a function of time. The reference sample should have a well-defined heat capacity over the range of temperatures to be scanned. Additionally, the reference sample must be stable, of high purity, and must not experience much change across the temperature scan. Typically, reference standards have been metals such as indium, tin, bismuth, and lead, but other standards such as polyethylene and fatty acids have been proposed to study polymers and organic compounds, respectively. The technique was developed by E. S. Watson and M. J. O'Neill in 1962, and introduced commercially at the 1963 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. The first adiabatic differential scanning calorimeter that could be used in biochemistry was developed by P. L. Privalov and D. R. Monaselidze in 1964 at Institute of Physics in Tbilisi, Georgia. The term DSC was coined to describe this instrument, which measures energy directly and allows precise measurements of heat capacity.
In 1980, Lady Hamilton Fairley, the widow of Sir Neil Hamilton Fairley began a campaign to have a memorial to Florey in London. The Premier of South Australia, David Tonkin, agreed to provide South Australian marble for a memorial stone. South Australian sculptor Paul Trappe was commissioned to engrave it from a design by John Peters. The 60-by-90-centimetre (24 by 35 in) stone was flown to London by the Royal Australian Air Force, and unveiled by Lady (Margaret) Florey on 2 November 1981. The inscription on the stone reads:
Uranium–lead radiometric dating involves using uranium-235 or uranium-238 to date a substance's absolute age. This scheme has been refined to the point that the error margin in dates of rocks can be as low as less than two million years in two-and-a-half billion years. An error margin of 2–5% has been achieved on younger Mesozoic rocks. Uranium–lead dating is often performed on the mineral zircon (ZrSiO4), though it can be used on other materials, such as baddeleyite and monazite (see: monazite geochronology). Zircon and baddeleyite incorporate uranium atoms into their crystalline structure as substitutes for zirconium, but strongly reject lead. Zircon has a very high closure temperature, is resistant to mechanical weathering and is very chemically inert. Zircon also forms multiple crystal layers during metamorphic events, which each may record an isotopic age of the event. In situ micro-beam analysis can be achieved via laser ICP-MS or SIMS techniques. One of its great advantages is that any sample provides two clocks, one based on uranium-235's decay to lead-207 with a half-life of about 700 million years, and one based on uranium-238's decay to lead-206 with a half-life of about 4.5 billion years, providing a built-in crosscheck that allows accurate determination of the age of the sample even if some of the lead has been lost. This can be seen in the concordia diagram, where the samples plot along an errorchron (straight line) which intersects the concordia curve at the age of the sample.
== Other uses == Additional district magistrate, a civil service officer in India, below district magistrate Adel–De Soto–Minburn Community School District, in Adel, Iowa, US A.D.M. (album), by New Zealand band Snapper, 1996 ADM (Amsterdam), a former squat in the Port of Amsterdam Alex de Minaur, an Australian professional tennis player
== History == Caleb Hillier Parry first made the association between the goiter and eye protrusion in 1786; however, he did not publish his findings until 1825. In 1835, Irish doctor Robert James Graves discovered a link between the protrusion of the eyes and goiter, giving his name to the autoimmune disease now known as Graves' Disease.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.
Aspartate can cyclise into a succinimide intermediate that later hydrolyses back as isoaspartate. Both forms share the same molecular mass, so mass spectrometry alone cannot tell them apart. This shapes how purity data should be interpreted.
Freeze-dried material is normally kept desiccated below minus twenty degrees Celsius and shielded from light. Solutions are prepared shortly before use and held cold. Repeated thawing is avoided because it accelerates aggregation and degradation.
No. Epithalamin is a peptide-containing extract of bovine pineal glands, while epitalon is a single synthetic tetrapeptide. The extract contains many peptides and other tissue components, so its composition varies between batches in ways that a synthesised sequence does not.