The short version of tetrapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-14. 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 peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
| 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 |
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
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.
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.
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.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
Solid-liquid extraction based ambient ionization is based on the use of a charged spray, for example electrospray to create a liquid film on the sample surface. Molecules on the surface are extracted into the solvent. The action of the primary droplets hitting the surface produces secondary droplets that are the source of ions for the mass spectrometer. Desorption electrospray ionization (DESI) is one of the original ambient ionization sources and uses an electrospray source to create charged droplets that are directed at a solid sample. The charged droplets pick up the sample through interaction with the surface and then form highly charged ions that can be sampled into a mass spectrometer. Desorption atmospheric pressure photoionization (DAPPI) is a solid-liquid extraction ambient ionization method that enables the direct analysis of samples deposited on surfaces by means of a jet of hot solvent vapour and ultraviolet light. The hot jet thermally desorbs the sample from a surface and the vaporized sample is ionized by a vacuum ultraviolet light and consequently sampled into a mass spectrometer.
The aerosol or spallation frangible powder produced by impact and combustion of depleted uranium munitions (or armour) can potentially contaminate wide areas around the impact sites, leading to possible inhalation by human beings. The actual level of acute and chronic toxicity of DU is also controversial. Several studies using cultured cells and laboratory rodents suggest the possibility of leukemogenic, genetic, reproductive, and neurological effects from chronic exposure. A 2005 epidemiology review concluded "In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU." A 2021 study concluded that DU from exploding munitions did not lead to Gulf War illness in American veterans deployed in the Gulf War. A 2011 study found elevated levels of uranium in soil and hair samples from Fallujah, Iraq, but it was from slightly enriched uranium instead of DU.
== Contraindications == Pioglitazone cannot be used in patients with a known hypersensitivity to pioglitazone, other thiazolidinediones or any of the components of its pharmaceutical forms. It is ineffective and possibly harmful in diabetes mellitus type 1 and diabetic ketoacidosis. Its safety in pregnancy, lactation (breastfeeding) and people under 18 is not established. Given previous experiences with the related drug troglitazone, acute diseases of the liver are regarded as a contraindication for pioglitazone.
Cambrex Corporation is a contract manufacturing organization in the pharmaceutical industry. Cambrex has manufacturing facilities in the US (Agawam, MA; Charles City, IA; Durham, NC; High Point, NC; Longmont, CO; Waltham, MA) and Europe (Edinburgh, UK; Karlskoga, Sweden, Milan, Italy, and R&D centers in Tallinn, Estonia, Wiesbaden, Germany). The headquarters are located in East Rutherford, NJ.
Sources: en.wikipedia.org
== Medical uses == Sufentanil offers properties of sedation and can be used as analgesic component of anesthetic regimen during an operation. Because of its extremely high potency, it is often used in surgery and post-operative pain management for patients that are heavily opioid dependent/opioid tolerant because of long term opiate use for chronic pain or illicit opiate use. It is also used in surgery and post-operative pain control in people that are taking high dose buprenorphine for chronic pain because it has the potency and binding affinity strong enough to displace buprenorphine from the opioid receptors in the central nervous system and provide analgesia. In 2018, the Food and Drug Administration (FDA) approved Dsuvia, a sublingual tablet form of the drug, that was developed in a collaboration between AcelRx Pharmaceuticals and the United States Department of Defense for use in battlefield settings where intravenous (IV) treatments may not be readily available. The decision to approve this new potent synthetic opioid came under criticism from politicians and from the chair of the FDA advisory committee, who fear that the tablets will be easily diverted to the illegal drug market. Dsuvia has since been withdrawn from the market due to "unresolvable manufacturing constraints."
=== Neoantigens === Many tumors express mutations. These mutations potentially create new targetable antigens (neoantigens) for use in T-cell immunotherapy. The presence of CD8+ T cells in cancer lesions, as identified using RNA sequencing data, is higher in tumors with a high mutational burden. The level of transcripts associated with the cytolytic activity of natural killer cells and T cells positively correlates with mutational load in many human tumors. In non–small cell lung cancer patients treated with lambrolizumab, mutational load shows a strong correlation with clinical response. In melanoma patients treated with ipilimumab, the long-term benefit is also associated with a higher mutational load, although less significantly. The predicted MHC binding neoantigens in patients with a long-term clinical benefit were enriched for a series of tetrapeptide motifs that were not found in tumors of patients with no or minimal clinical benefit. However, human neoantigens identified in other studies do not show the bias toward tetrapeptide signatures. Finally, effectiveness of neoantigens may also be regulated by the specific HLA repertoire possessed by specific patient sub-groups.
=== Terrace function and structure === The Inca faced many problems with living in areas with steep terrain. Two large issues were soil erosion and area to grow crops. The solution to these problems was the development of terraces, called Andenes. These terraces allowed the Inca to utilize the land for farming that they never could in the past. Everything about how the terrace functions, looks, its geometric alignment, etc. all depend on the slope of the land. The different layering of materials is part of what makes the terraces so successful. It starts with a base layer of large rocks, followed by a second layer of smaller rocks, then a layer of sand-like material, and finally the topsoil. You can practice this in a simulation here. The most impressive part of the terraces was their drainage systems. Drain outlets were placed in the numerous stone retaining walls. The larger rocks at the base of each terrace level are what allowed the water to flow more easily through the larger spaces in between the rocks, eventually coming out at the “Main Drain”. The Inca even constructed different types of drainage channels that are used for different purposes throughout the city.
l-DOPA is produced from the amino acid l-tyrosine by the enzyme tyrosine hydroxylase. l-DOPA can act as an l-tyrosine mimetic and be incorporated into proteins by mammalian cells in place of l-tyrosine, generating protease-resistant and aggregate-prone proteins in vitro and may contribute to neurotoxicity with chronic l-DOPA administration. It is also the precursor for the monoamine or catecholamine neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). Dopamine is formed by the decarboxylation of l-DOPA by aromatic l-amino acid decarboxylase (AADC). l-DOPA can be directly metabolized by catechol-O-methyl transferase to 3-O-methyldopa, and then further to vanillactic acid. This metabolic pathway is nonexistent in the healthy body, but becomes important after peripheral l-DOPA administration in patients with Parkinson's disease or in the rare cases of patients with AADC enzyme deficiency. l-Phenylalanine, l-tyrosine, and l-DOPA are all precursors to the biological pigment melanin. The enzyme tyrosinase catalyzes the oxidation of l-DOPA to the reactive intermediate dopaquinone, which reacts further, eventually leading to melanin oligomers. In addition, tyrosinase can convert tyrosine directly to l-DOPA in the presence of a reducing agent such as ascorbic acid.
A photograph of the deceased in good health is often sought to guide the embalmer's hand in restoring the body to a more lifelike appearance. Blemishes and discolorations (such as bruises, in which the discoloration is not in the circulatory system, and cannot be removed by arterial injection) occasioned by the last illness, the settling of blood, or the embalming process itself are also dealt with at this time (although some embalmers utilize hypodermic bleaching agents, such as phenol-based cauterants, during injection to lighten discoloration and allow easier cosmeticizing). It is also common for the embalmer to perform minor restoration of the deceased's appearance with tissue building chemicals and a hypodermic syringe. Tissue building chemicals (Tissue Builders) become solid with the introduction of liquids such as water or interstitial fluids. Commonly the area where the sphenoid and temporal bones meet; this can also be referred to the temples. In the event of trauma or natural depressions on the face or hands, tissue builder can also be utilised to return those regions of the face to the expectations of the family.
Sources: en.wikipedia.org
==== The Yellow Emperor's Classic of Internal Medicine (475 BC – 8 AD) ==== Huángdì Nèijīng (黃帝內經), or The Yellow Emperor's Classic of Internal Medicine, is a fundamental ancient text in Chinese medicine and a major book of Daoist philosophy and lifestyle. It is generally dated to the late Warring States period (475–221 BC) and the Western Han dynasty (206 BC – 8 AD). The text named the condition xiāo kě (消渴; "wasting-thirst") and elaborated on it through 25 clauses. It recorded such symptoms as "three increases [excess] and one decrease [loss]": excessive thirst (polydypsia), excessive hunger (polyphagia), excessive urine (polyuria), and weight loss. Three sub-phases of xiāo kě were given, characterized by their dominant symptoms. These roughly correspond to the progressive stages of diabetes in modern-day Western medicine.
Hyperthyroidism (an example is Graves' disease) is the clinical syndrome caused by an excess of circulating free thyroxine, free triiodothyronine, or both. It is a common disorder that affects approximately 2% of women and 0.2% of men. Thyrotoxicosis is often used interchangeably with hyperthyroidism, but there are subtle differences. Although thyrotoxicosis also refers to an increase in circulating thyroid hormones, it can be caused by the intake of thyroxine tablets or by an over-active thyroid, whereas hyperthyroidism refers solely to an over-active thyroid. Hypothyroidism (an example is Hashimoto's thyroiditis) is the case where there is a deficiency of thyroxine, triiodothyronine, or both. Clinical depression can sometimes be caused by hypothyroidism, whereas bipolar disorder can sometimes be caused by hyperthyroidism. Some research has shown that T3 is found in the junctions of synapses, and regulates the amounts and activity of serotonin, norepinephrine, and γ-aminobutyric acid (GABA) in the brain. Hair loss can sometimes be attributed to a malfunction of T3 and T4. Normal hair growth cycle may be affected disrupting the hair growth. Both thyroid excess and deficiency can cause cardiovascular disorders or make preexisting conditions worse. The link between excess and deficiency of thyroid hormone on conditions like arrhythmias, heart failure, and atherosclerotic vascular diseases, have been established for nearly 200 years.
=== Manufacture === The development of the fluorocarbon industry coincided with World War II. Prior to that, fluorocarbons were prepared by reaction of fluorine with the hydrocarbon, i.e., direct fluorination. Because C-C bonds are readily cleaved by fluorine, direct fluorination mainly affords smaller perfluorocarbons, such as tetrafluoromethane, hexafluoroethane, and octafluoropropane.
=== Rule of 13 === The Rule of 13 is a simple procedure for tabulating possible chemical formula for a given molecular mass. The first step in applying the rule is to assume that only carbon and hydrogen are present in the molecule and that the molecule comprises some number of CH "units" each of which has a nominal mass of 13. If the molecular weight of the molecule in question is M, the number of possible CH units is n and
== Routine Immunization Schedule for Infants == The standard routine immunization schedule for infants in the Philippines is adopted to provide maximum immunity against the seven vaccine preventable diseases in the country before the child's first birthday. The fully immunized child must have completed BCG 1, DPT 1, DPT 2, DPT 3, OPV 1, OPV 2, OPV 3, HB 1, HB 2, HB 3 and measles vaccines before the child is 12 months of age.
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.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.